Cy 1201 Environmental Science and Engineering
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LECTURE NOTES ON
ENVIRONMENTAL SCIENCE AND ENGINEERINGERING
Prepared By
D.PARTHIBAN LECTURER IN CHEMISTRY PRATHYUSHA INSTITUTE OF TECHNOLOGY AND MANAGEMENT ARANVOYALKUPPAM THIRUVALLUR PIN-602 025
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SYLLABUS
TOTAL PERIOD = 45 TEXT BOOKS 1. Gilbert M.Masters, Introduction to Environmental Engineering and Science, Pearson Education Pvt., Ltd., Second Edition, Isbn 81-297-0277-0, 2004. 2. Miller T.G., Jr., Environmental Science, Wadsworth Publishing Co. 3. Townsend C., Harper J and Michael Begon, Essentials of Ecology, Blackwell Science. 4. Trivedi R.K. and P.K. Geol, Introduction to Air Pollution, Techno-Science Publication. REFERENCES 1. Bharucha Erach, The Biodiversity of India, Mapin Publishing Pvt. Ltd., Ahmedabad, India. 2. Trivedi R.K., Handbook of Environmental Laws, Rules, Guidelines, Compliances and Standards, Vol. I and II, Environ Media. 3. Cunningham, W.P. Cooper, T.H. Gorhani, Environmental Encyclopedia, Jaico Publ., House, Mumbai, 2001. 4. Wager K.D., Environmental Management, W.B. Saunders Co., Philadelphia, USA, 1998.
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// ENGINEERING AND SCIENCE ENVIRONMENTAL
1. INTRODUCTION TO ENVIRONMENTAL STUDIES AND NATURAL RESOURCES 10 Definition, Scope and Importance – Need for Public Awareness – Forest Resources: Use and Over – Exploitation, Deforestation, Case Studies. Timber Extraction, Mining, Dams and their Ground water, Floods, Droughts, Conflicts Over Water, Dams – Benefits and Problems – Mineral Resources: Use Effects On Forests and Tribal People – Water Resources: Used and Over-Utilization of Surface and Exploitation, Environmental Effects of Extracting and Using Mineral Resources, Case Studies – Food Resources: World Food Problems, Changes Caused by Agriculture and Overgrazing, Effects of Modern Agriculture, Fertilizer – Pesticide Problems, Water Logging, Salinity, Case Studies – Energy Resources: Growing Energy Needs, Renewable and Non Renewable Energy Sources, Use of Alternate Energy Sources. Case Studies – Land Resources: Land as a Resource, Land Degradation, Man Induced Landslides, Soil Erosion and Desertification – Role of an Individual in Conservation of Natural Resources – Equitable use of resources for sustainable lifestyles.Field Study of Local Area to Document Environmental Assets – River / Forest / Grassland / Hill / Mountain. 2. ECOSYSTEMS AND BIODIVERSITY 14 Concepts of an Ecosystem – Structure and Function of an Ecosystem – Producers, Consumers and Decomposers – Energy Flow in the Ecosystem – Ecological Succession – Food Chains, Food Webs and Ecological Pyramids – Introduction, Types, Characteristics Features, Structure and Function of the (A) Forest Ecosystem (B) Grassland Ecosystem (C) Desert Ecosystem (D) Aquatic Ecosystems (Ponds, Streams, Lakes, Rivers, Oceans, Estuaries) – Introduction to Biodiversity – Definition: Genetic, Species and Ecosystem Diversity – Biogeographically Classification of India – Value of Biodiversity: Consumptive Use, Productive Use, Social, Ethical, Aesthetic and Option Values – Biodiversity at Global, National and Local Levels – India as A Mega-Diversity Nation – Hot-Spots of Biodiversity – Threats to Biodiversity: Habitat Loss, Poaching of Wildlife, Man-Wildlife Conflicts – Endangered and Endemic Species of India – Conservation of Biodiversity: In-Situ and Ex-Situ Conservation of Biodiversity. 3. ENVIRONMENTAL POLLUTION 8 Definition – Causes, Effects and Control Measure of: (A) Air Pollution (B) Water Pollution (C) Soil Pollution (D) Marine Pollution (E) Noise Pollution (F) Thermal Pollution (G) Nuclear Hazards – Soil Waste Management: Causes, Effect and Control Measures of Urban and Industrial Wastes – Role of an Individual in Prevention of Pollution – Pollution Case Studies – Disaster Management: Floods, Earthquake, Cyclone and Landslides. Field Study of Local Polluted Site – Urban / Rural / Industrial / Agricultural. 4. SOCIAL ISSUES AND THE ENVIRONMENT 7 From Unsustainable to Sustainable Development – Urban Problems Related to Energy – Water Conservation, Rain Water Harvesting, Watershed Management – Resettlement and Rehabilitation of People; Its Problems and Concerns, Case Studies – Environmental Ethics: Issues and Possible Solutions – Climate Change, Global Studies – Wasteland Reclamation – Consumerism and Waste Products – Environment Production Act – Air (Prevention and Control of Pollution) Act – Water (Prevention and Control of Pollution) Act – Wildlife Protection Act – Forest Conservation Act – 23ssues Involved in Enforcement of Environmental Legislation – Public Awareness. 5. HUMAN POPULATION AND THE ENVIRONMENT 6 Population Growth, Variation Among Nations – Population Explosion – Family Welfare Programme – Environment and Human Health – Human Rights – Value Education – HIV / Aids – Women and Child Welfare – Role of Information Technology in Environment and Human Health – Case Studies.
D.PARTHIBAN
CY 1201 ENIVRONMENTAL SCIENCE AND ENGINEERING
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CHAPTER-I PROVIDES INFORMATION ON:
DEFINITION, SCOPE AND IMPORTANCE FOREST RESOURCES WATER RESOURCES MINERAL RESOURCES FOOD RESOURCES ENERGY RESOURCES LAND RESOURCES
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ENVIRONMENTAL
SCIENCE
AND
ENGINEERING
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D.PARTHIBAN
െ ͳǣ
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INTRODUCTION TO ENVIRONMENTAL STUDIES AND NATURAL RESOURCES NATURAL RESOURCES
Natural resources are goods and services supplied by our environment. These include forest, water, mineral, food, energy, land (soil), Atmosphere (air), plants and animals.
1) Renewable Resources (Inexhaustible Resources): Inexhaustible resources have the ability to reappear or replenish themselves by recycling, reproduction or replacement. These renewable sources include
2) Non-renewable Resources (Exhaustible Resources): The non- renewable resources are the earth’s materials. These renewable sources include Minerals, Fossil fuels, Non-mineral resources
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ENGINEERING
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Sunlight, Plants, Animals, Soil, Water Living organisms
NATURAL RESOURCES- AN OVERVIEW Resources are needed for the development of civilization. Natural resources are the materials provided by the nature that are required to sustain life and livelihood. They include air, water, land, food, timber, paper, medical plants, minerals, fuel, etc. Everything that human beings use is drawn from the nature. Due to increased standards of living results in excessive utilization of natural resources. However, the natural resources are limited. They should be properly and optimally used for a comfortable living. The entire living system will collapse when the utility exceeds the regeneration capacity. Forest Wealth Forests are valuable source of biodiversity from which we derive various benefits like medicines, domesticated plants, animals, etc. Forest reduces the impact of raindrop by covering
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SCIENCE
D.PARTHIBAN
Some resources are get exhausted soon, whereas other resources would be lasting for a long period of time. Depending on this factor, these resources are divided into two categories.
ENVIRONMENTAL
“There
is enough for everyone’s need, but not enough for everyone’s greed”
- M.K.GANDHI
UNIT – 1
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the surface of the land with litter and leaves. This results in reduction of soil erosion, in turn floods in rivers. It moderates climate. Forest provides livelihood for large sector of tribal people. It also fulfills timber, fuel-wood, fruits, fibre, recreation and other benefits. These are self managed ecosystems by way of managing and maintaining themselves in the absence of human interference. It maintains the natural ecological balance by providing habitat for various species of plants and animals.
Minerals are formed through geochemical process over a long span of period. India is rich in mineral reserves. Coal resource is the largest. India is the 5th largest producer of coal in the world with total reserve of coal estimated at 186044 million. India has the 5th largest deposit of bauxite in the world. 95% of India’s lead-zinc resources are located in Rajasthan and Gujarat. Limestone is found in all the states of India. The country is relatively poor in gold, base metals, platinum, diamond, nickel, and tungsten and rock phosphate. As population increases the demands on the mineral usage is also increasing rapidly. In the next 50 years most of our mineral resources will get exhausted. Therefore these non-renewable resources are to be consumed less and preventing wastage, recycling and reuse, choosing renewable alternative.
The mining extraction, purifying, refining and processing operations are likely to cause the following effects, 1. 2. 3.
Disturbing landscape, forest, wildlife, Releasing of toxic pollutants Water and air pollution
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// ENGINEERING AND
Mineral Resources
SCIENCE
In India, 22% of the land is covered by forest i.e., around 60 million hectare. This works out to be 0.06 hectare/person which are far less than the world’s average of 0.64 hectare/capita. It is required to know the prime causes of deforestation which includes increased population and industrialization, mineral exploration, construction of dam, transportation, over grazing, agricultural operation, illegal human trade, etc.
ENVIRONMENTAL
Deforestation is thought to induce regional and global climate changes. Trees releases substantial amount of moisture into the air, and about 97% of water through roots absorb from the soil is evaporated directly into the atmosphere as transpiration. The moisture finds its way back to the earth in the hydrologic cycle. When large form is decimated, rainfall is likely to decline and drought may become more common in that region. The effective forest management includes restricting cutting tress, reforestation, control of forest fire, replacing and recycling of forest products.
D.PARTHIBAN
They provide shelter to large number of animals and birds. In fact tropical rain forests are the best sources of diversity of animals. These animals are not only aesthetically valuable but represent a tremendous store of genes. These genes have been evolving over millions of years, so when one species of animals or plant become extinct, a very valuable source of genetic information is lost. Our wheat, rice, ragi, sugar cane, etc., are also descendants of once wild grasses.
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Land degradation
Water Resources Precipitation is the primary source of water which may be in the form of surface water and groundwater available for our use. Much of this will be known in the subsequent lectures.
Land is a declinable area of the earth’s terrestrial surface, encompassing all attributes of the biosphere immediately above or below this surface including those of the near surface climate the soil and terrain forms the surface hydrology (including shallow lakes, river, marshes and swamps), the near surface sedimentary layers and associated groundwater resource, the plant and animal populations, the human settlement pattern and physical results of past and present human activity (terracing, water storage or drainage structures, roads, buildings, etc.). Conservation of Natural Resources As the human population increases, greater demands are placed upon the available resources. Large areas of earth are being converted for in exclusive use of human beings. This result in several changes does occur in various components of the biosphere such as pollution of seas, rivers and lakes, denudation of forest, degradation of land. The problem lies is what will happen to our future generation, if the natural resources are used injudiciously at a rapid rate. At present, world environment is suffering critical stress not only by our utilization of natural resources but the greater environmental change. For all these Sustainable Environmental Management System has to be adopted through individuals, value system and prevention of pollution.
“THE” FOREST RESOURCES pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA
// ENGINEERING
Land Resources
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Global food supply has improved enormously since 1960’s. Agricultural production has increased and world food supplies are 18% higher than 30 years ago. Food security is the ability of all people at all time to access enough food for an active and healthy life. Food insecurity is not just a problem related to food production; it is closely linked to poverty and economic stagnation.
SCIENCE
Food Resources
ENVIRONMENTAL
The power we use is mostly Hydel or thermal or nuclear origin. Alternate energy refers renewable energy sources (rather than burning the fossil fuels like petroleum and coal production) which will never exhaust viz.; wind energy, geothermal energy, biomass, solar energy, etc. The renewable energy is the need of the hour because fossil fuels are getting exhausted very fast. In India, for every year 300 million tons of agro residues produced to get biogas. The biomass programme propagates the protection of fast growing species of trees to meet fuel fodder and power requirements particularly rural areas. Wind energy produces electricity at a very lower cost with no emission and no big investment. Tidal and geothermal energy are yet to be exploited to economical scale.
D.PARTHIBAN
Energy Resources
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Forests are important renewable resources. A forest is a vast biotic community of trees, shrubs or any other woody vegetation. Forests contribute a lot to the economic development of a country. Some of the uses of forest are:
Fuel wood, Timber Wildlife habitat* Pasture for livestock Industrial forest products Animal products Recreation Soil moisture retention Climate regulation Production of atmospheric oxygen Source of new agricultural land Grazing land
Nearly 96% of the forests are owned by the Government, 2.6% by corporate bodies and the rest are in private ownership.
USES OF THE FORESTS: 1. Economical uses: Forests provide us a large number of commercial products which include timber, firewood, pulpwood, food items, gum, resins, non-edible oils, rubber, fibers, bamboo canes, animal food, medicine, drugs etc. 2. Ecological uses: Production of oxygen: The trees produce oxygen by photo synthesis. Oxygen is very vital for human life. Hence forests are called as earth's lungs. Reducing global warming:
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// ENGINEERING
38.7% 30.9% 6.9%
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Tropical dry deciduous forest = Tropical moist deciduous forest = Tropical thorn forest =
SCIENCE
` ` `
ENVIRONMENTAL
The total forest area of India is 637,293 square kilometers, which is 19.39% of the total geographical area of our country.
D.PARTHIBAN
*Habitat: The type of environment in which an organism or group of organisms lives or occurs
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The main green house gas carbon dioxide (CO2) is absorbed by the forests as a raw material for photosynthesis. Thus forest acts as a sink for CO2 thereby reducing global warming. Wild life habitat: Forests are the homes of millions of wild animals and green plants. Nearly seven million species are found in the tropical forests alone. Regulation of hydrological cycle: Forested watersheds act like big sponges, absorbing the rainfall, slowing down the runoff. About 50-80 % of the moisture in the air above tropical forests comes from their transpiration which helps in bringing rains. It also helps in control of floods. Soil Conservation: Forests bind the soil particles tightly in their roots and prevent soil erosion.
The total forest area of the world in 1900 = 7,000 million hectares The total forest area of the world in 1975 = 2,890 million hectares The total forest area of the world in 2000= 2,300 million hectares CAUSES OF DEFORESTATION
Shifting cultivation: More than 5 lakh hectares of forests are cleared for shifting cultivation annually. In India, we have this shifting cultivation in Andhra Pradesh, Bihar and Mathya Pradesh.
Fuel requirements: There are great demands for fuel wood due to growing population. This situation increases the pressure on forests, In India, Fuel wood requirement in 1950’s = 65 million tons Fuel wood requirement in 2000’s = 300-500 million tons
Raw materials for industries: Wood for making boxes, furniture, railway-sleepers, plywood, match-boxes, pulp for paper industry etc. have exerted a great pressure on forests.
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// ENGINEERING
DEFORESTATION
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Many forest lands are used for mining, agriculture, grazing, recreation and for development of dams. Excessive use of fuel wood and charcoal, expansion of urban, agricultural and industrial areas and overgrazing have together lead to over-exploitation and degradation of the forests.
SCIENCE
OVEREXPLOITATION:
ENVIRONMENTAL
Forests can absorb many toxic gases and can help in keeping the air pure. They also absorb noise and thus help in preventing air and noise pollution.
D.PARTHIBAN
Pollution moderators:
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Development projects: Due to development projects like hydroelectric power plants, dams construction, road construction, mining, a massive destruction of forests occurs.
Growing food needs: To meet the demands of rapidly growing population, agricultural lands are expanded and new homes and avenues are created by clearing forests.
Overgrazing: Overgrazing by the domestic animals like cattle leads to destruction of forests. EFFECTS OF DEFORESTATION
Soil erosion: the soil in slope area gets washed away with rain water, since soil become loose due to the absence of forests/trees.
Expansions of deserts: barren land is getting converted into deserts due to the action of strong winds. Since there is no barrier to strong wind because of absence of trees.
products and loss of long-term productivity on the site.
Loss of biodiversity: Loss of flora and fauna leads to disturbances in ecological balance worldwide. Certain species of flora and fauna are getting extinct.
Loss of medicinal plants: There are many species of plants which have medicinal and other advantages, like Neem (“Vempoo” in Tamil) which has been used in India for centuries
as insecticide, fungicide, in medicine and in bio-fertilizers. Such medicinal plants are destructed. Environmental changes: The air is purified by forests. So, deforestation will lead to increase in carbon dioxide and other air pollutants concentration. This will lead to global warming, In many places the lack of fuel wood due to deforestation challenges local/tribal people,(economically poor people cannot afford LPG gas for domestic cooking) Agriculture may be negatively impacted if deforestation causes soil loss or compaction, or sedimentation of irrigation systems. Indigenous people may be forced into a new way of life for which they are unprepared.
Human life in the downstream of a river may be endangered by floods that may be intensified by clearing forests on upstream watersheds.
MINING:
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// ENGINEERING
Economic losses: Deforestation will cause loss of industrial timber and non-timber
AND
SCIENCE
vegetation. Effect on climate: The climate of a region is mainly controlled by the rainfall, snowfall, etc. Deforestation causes decrease in rainfall, which in turn increases the climatic temperature. Lowering of water table: Decrease in rainfall results into a lowered water table due to lack of recharging of underground reservoirs.
ENVIRONMENTAL
precipitation. In the absence of forests, rainfall declines considerably.
Loss of fertile land: Less rainfall results into the loss of fertile land owing to less natural
D.PARTHIBAN
Decrease in rainfall: Forests bring rains due to high rate of transpiration and
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Mining operations for extracting minerals and fossil fuels like coal often involves destruction of vast forest areas. Mining from shallow deposits is done by surface mining while that from deep deposits is done by sub-surface mining. More than 80,000 ha of land of the country is presently under the stress of mining activities. Mining and its associated activities require removal of vegetation along underlying soil. This results in change and destruction of the landscape area.
with
ILL-EFFECTS OF MINING
→ → → → → →
No of big dams in India = more than 1550 No of big dams in Maharashtra = more then 600 No of big dams in Gujarat = more then 250 No of big dams in Madhya Pradesh = more than 130 The highest dam is Tehri dam, on river Bhagirathi in Uttaranchal The largest in terms of capacity is Bhakra dam on river Satluj in H.P.
IMPACTS OF DAMS CONSTRUCTION Degradation of catchment areas. Reservoir induced seismicity. Deforestation and loss of fauna and flora including gene pool reserves due to submergence. Increased incidence of water-borne diseases like malaria, filaria, diaria, etc. Disturbance of the dam (or reservoir) site forest ecosystem may result in important changes in the neighboring and other ecosystems that may be separated by great distances. Scarcity of fuel wood and other forest products for tribal people.
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DAMS:
AND
ø ø ø ø ø ø ø
SCIENCE
ø ø
Degradation of lands. Loss of top soil due to deforestation. Pollution of surface and ground water resources due to the discharge of highly mineralized mine waters. Lowering of ground water table. Air pollution due to release of greenhouse gases and other toxic gases during mining, e.g. release of CH4 during coal mining. Deforestation including loss of flora and fauna. Ore transport hazards. Fire/explosive hazards. Subsidence above and near mine areas. Drying up of the perennial sources of water like springs and streams in hilly areas. Tribal people may be forced into a new way of life for which they are unprepared. Migration of tribal people from mining areas to other areas in search of land and food.
ENVIRONMENTAL
ø ø ø
D.PARTHIBAN
The major effects of mining operations on forests and tribal people include:
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Rehabilitation and resettlement of tribal people affected. loss of vegetal cover submergence of large area of land(human settlement) soil erosion, Resettlement and rehabilitation problem of displaced
variation in water table and Enhanced seismic activities due to pressure of water. Salts left behind by evaporation increase salinity of the river and make it unusable. Dams - Benefits
increase river depths for navigational purposes; control water flow during times of flood and drought; create artificial lakes for recreational use.
CASE STUDIES # 1
reactant,
coolant,
@ Water is a vital natural resource which forms the basis of all life. It is an essential raw material in the process of photosynthesis of green plants. Aquaculture has come up as a very potent industry. Water is source for generation of Hydroelectric Power. Water is used as a raw material, solvent, chemical and cleaning agent.
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ENVIRONMENTAL
“THE” WATER RESOURCES
SCIENCE
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The Sardar Sarovar dam is situated on river Narmada and is spread over three states of Gujarat, Maharashtra and Madhya Pradesh. The project is aimed at providing irrigation water, drinking water and electricity to the three states. A total of 1,44,731 hectares of land will be submerged by the dam, out of which 56,547 hectares are forest land. A total of 573 villages are to be submerged by the Narmada Dam. Submergence area is very rich in wildlife e.g. .tigers, panthers, bears, wolves, pangolins, hyenas, jackals, flying squirrels, antelopes, black bucks, chinkara, marsh crocodiles, turtles etc.
D.PARTHIBAN
concentrate the natural fall of a river at a given site; generate electricity; direct water from rivers into canals ,irrigation and water-
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To To To supply systems; To To To
ENGINEERING
Egypt was developed on the bank of the Nile; Babylon on the bank of the Tigris; North India on the bank of the Ganges; Europe on the bank of the Rhine, China on the bank of Yellow River.
Rivers were centre for many civilization
people.
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@ Water is very abundant on this earth, yet it is very precious. Out of the total water reserves of the world, about 97% is salty water (marine) and only 3% is fresh water. Even this small fraction of fresh water is not available to us as most of it is locked up in polar ice caps and less than 1% is readily available to us in the form of groundwater and surface water. @ United Nations estimates (2002), at least 101 billion people do not even have access to safe drinking water and 2.4 billion do not have adequate sanitation facilities. @ Increasing population and expanding development would further increase the demands for wastes. It is estimated that by 2024, 2/3rd of the world population would be suffering from severe water shortage. Ground Water: # A layer of sediment or rock that is highly permeable and contains water is called an aquifer.
S.NO
RESERVOIR
VOLUME
TOTAL WATER
1
Oceans
1,338,000 x 1000 km3
96.5 %
2
Ice and snow
24,364
x 1000 km3
1.76 %
3
Saline ground water
12,870
x 1000 km3
0.93 %
4
Fresh ground water
10,530
x 1000 km3
0.76 %
5
Fresh lakes
91
x 1000 km3
0.007 %
6
Saline lakes
85
x 1000 km3
0.006 %
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ENVIRONMENTAL
WATER RESERVOIRS
SCIENCE
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# Groundwater is becoming contaminated with industrial effluents discharged on land and septic systems, as well as illegal and uncontrolled hazardous waste sites. Once contaminated, groundwater is difficult to restore.
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# Groundwater is the source of about 90% countries’s drinking water. In rural areas, groundwater is the only source for water
ENGINEERING
# Rain water move downward and get stopped when the water meets rock that has no porosity.
D.PARTHIBAN
# Layers of sand and gravel are good aquifers while clay and crystalline rocks (like granite) are not since they have low permeability.
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Soil moisture
16.5
x 1000 km3
0.001 %
8
Atmosphere
12.9
x 1000 km3
0.001 %
9
Wetlands
11.5
x 1000 km3
0.001 %
10
Rivers &streams
2.12
x 1000 km3
0.0002 %
11
Living organisms
1.12
x 1000 km3
0.0001 %
Total
1,386,000 x1000 km3
13
100 %
o o o
Subsidence: When groundwater withdrawal is more than its recharge rate, the sediments in the aquifer get compacted, a phenomenon known as ground subsidence. Lowering of water table: Mining of groundwater is done extensively in arid and semiarid regions for irrigating crop fields. Water logging: When excessive irrigation is done with brackish(salty)it raises the water table gradually leading to water-logging and salinity problems.
D.PARTHIBAN
Effects of Groundwater Usage
ENVIRONMENTAL
SCIENCE
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Surface waters are available as a result of natural precipitation. Precipitation that doesn't seep into the ground or does not return to the atmosphere by evaporation or transpiration is called surface water. It forms streams, ponds, ocean, lakes, wetlands and artificial reservoirs.
ENGINEERING
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Surface Water:
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Overutilization ion of Surface and Ground Water: | |
SOURCES OF POLLUTION: Industries: Pulp, paper mills and steel industries, tanneries, distilleries, rayon mills, caustic soda mills, Fertilizer, fly ash from steel mills, Automobile workshops, chemical, metal and surgical industries; tanneries, textile mills, suspended coal, Thermal power stations, Jute, and domestic sewage of highly organic nature, Power stations; jute, textile mills; chemical, paint, varnishes, metal, steel, hydrogenated
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SCIENCE
Water moves from the ocean to air to land to ocean in a set cyclic pattern called hydrologic cycle. The factors which control the process of evaporation and transpiration include wind, temperature and humidity.
ENVIRONMENTAL
HYDROLOGICAL CYCLE OR WATER CYCLE
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ENGINEERING
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D.PARTHIBAN
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Population growth has created much demand of water due to increasing population and rapid industrialization The amount of water used in one toilet flush = drinking requirements of an adult (IL/day) for about three weeks; The water used for one load in washing machine = drinking for almost 6 months. The water used to refine a tonne of petroleum = 200 loads in a washing machine. Water required to grow a tonne of grain = manufacture a tonne of most industrial materials (e.g., e.g., metals or plastics, etc.).
Page: vegetable oil, soap, match, shellac and polythene industries, sulphur and sugar mills; cement industries.
industries;
yarn,
tin
and
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glycerin,
Floods: Floods occur when water from heavy rainfall, melting ice or snow or a combination of these, exceeds the carrying capacity of the receiving river system. During the floods, the river carries fertile sediment and deposits it on the level land along its lower course, Such areas are called flood plains which are very fertile. Causes of Floods
Floods occur when soil and vegetation cannot absorb all the water; water then runs off the land in quantities that cannot be carried in river channels or retained in natural ponds and constructed reservoirs held behind dams. Effects of Floods Rapid run-off cause’s soil erosion. The National Commission on floods has calculated that the land area prone to floods has doubled from 20 million hectares in 1971 to 40 million hectares in 1980.
Economical loss was Rs. 121 crore per year during the decade 1960-70, increasing to Rs. 739 crore per year during 197l- 78The worst suffering States are Assam, Bihar, Orissa, U.P. and West Bengal. So it is to be given serious thought to save further destruction of mankind.
Severe floods like that in 1970, 1988 and 1991 resulting from excessive Himalayan runoff and storms, had very disastrous consequences causing massive deaths and damages.
In 1970, about one million people were affected while 1, 40,000 people were died in 1991.
The basic methods to control floods practiced since ancient times are reforestation and the construction of dams, reservoirs, and floodways (artificial channels that divert floodwater).
The National Remote Sensing Agency (NRSA) sends regular flood maps along with data obtained through Radar satellite/ microwave satellite for assessing the intensity of flood situation in various States.
DROUGHTS
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AND SCIENCE ENVIRONMENTAL
Control of Floods
ENGINEERING
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D.PARTHIBAN
When it rains or snows, some of the water is retained by the soil, some is absorbed by vegetation, some evaporates, and the remainder, which reaches river channels, is called run-off.
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16
@
Definition: When annual rainfall drought conditions are created.
@
About 80 countries in the world lying in the arid and semi-arid regions that experience frequent spells of droughts.
is
below
normal and
less
than
evaporation,
Causes for drought: Due to several anthropogenic causes like over grazing, deforestation, mining etc. there is spreading of the deserts tending to convert more areas to drought affected areas. Consequences of Drought (a) Desertification: The processes by which an area becomes even more barren, less capable of retaining vegetation, and progresses towards becoming a desert. This is often a cause of long-term disasters.
(i) Reclamation of sewage and waste water (ii) Development of ground water sources and surface storages (iii) Long range forecasting of rain;
D.PARTHIBAN
Remedies for water problems
Irrigation water-supply systems in North Vietnam were bombed by the US in the late 1960's. Dam's, desalination plants and water reservoir systems were targeted during the 1991 Gulf War. Jordan River Basin is a small river, its basin is shared by Israel, Syria, Jordan and Lebanon. During 1967 Arab-Israeli War, Israel occupied much of the headwaters of the Jordan River, ensuring for itself a more reliable water supply . 97% of Egypt's water comes from the Nile River. Greater than 95% of the Nile's runoff originates in 8 other nations of the Basin: Sudan, Ethiopia, Kenya, Rwanda, Burundi, Uganda, Tanzania and Zaire. The construction of the Farakka Barrage across the Ganga by India to divert water into the Hoogley River to protect the Calcutta port from problems of silting, has been the subject of dispute between India and Bangladesh.
RIVER DISPUTES IN INDIA
S.NO
RIVER
DISPUTES
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AND
Conflicts over water
SCIENCE
(vi) Desalination of sea water.
ENVIRONMENTAL
(v) Transfer of surplus water; and
ENGINEERING
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(iv) Rain making;
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1
Yamuna
Delhi, Haryana, Rajasthan, Himachal Pradesh and U.P.
2
Narmada
Maharashtra, Gujarat, Rajasthan and Madhya Pradesh.
3
Krishna
Andhra Pradesh, Maharashtra, Tamilnadu , Karnataka
4
Godavari
Andhra Pradesh, Maharashtra, Orissa and Madhya Pradesh
5
Cauvery
Karnataka, Tamilnadu and Kerala
17
NATIONS TO DISPUTES
Ganga
India, Bangladesh and Nepal
Brahmaputra
India, Bangladesh
Euphrates
Turkey, Jordan, Syria, Iraq and Iran
Parana
Brazil, Paraguay, and Argentina
Danube
Hungary and Czechoslovakia (now Czech and Slovak Republics)
Colorado
US and Mexico
Zambezi
Zambia and Zimbabwe
Han
South Korea and North Korea
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AND SCIENCE ENVIRONMENTAL
“THE” MINERAL RESOURCES
ENGINEERING
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RIVER
D.PARTHIBAN
INTERNATIONAL WATER DISPUTES:
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Mineral: Any naturally occurring chemical element or compound that have been formed through inorganic processes. Minerals are exhaustible, non-renewable resources found in the earth's crust. More than 3,000 mineral species are known, most of which are characterized by definite chemical composition, crystalline structure, and physical properties. India has large reserves of iron, manganese, lime stone, dolomite, silica, and mica but has little reserves of copper, gold, silver, lead and phosphate.
Uses of Minerals Metals are classified into various category
4. Construction materials include sand, gravel, aggregates, brick clays and limestone, cement. Also included in this group are slate for roofing, and the polished stones, such as limestone, granite, travertine, and marble, collectively known as dimension stones. 5. Gemstones include diamonds, rubies, sapphires, and emeralds. METALS AND THEIR EXPECTED YEAR OF DEPLETION S.NO
RESOURCES
YEARS TO DEPLETION
1
Aluminium
31
2
Chromium
95
3
Copper
21
4
Iron
93
5
Lead
21
6
Manganese
46
7
Mercury
13
8
Molybdenum
34
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agriculture inputs,
ENGINEERING
3. Number of minerals used in industries, production of consumer's goods, hospitals and defense and research equipments
AND
2. Many minerals are essential for growth and functioning of the living organisms.
D.PARTHIBAN
sulphur,
SCIENCE
Precious metals: gold, silver, and the platinum group metals; Steel industry metals: iron, nickel, cobalt, titanium, vanadium, chromium; Base metals: copper, lead, tin, and zinc; magnesium and aluminium; Nuclear metals: uranium, radium, and thorium; Specialty metals: lithium, germanium, gallium, and arsenic. Industrial minerals: quartz, salt, potash, asbestos, talc, feldspar, phosphates.
ENVIRONMENTAL
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9
Nickel
53
10
Silver
13
11
Tin
15
12
Tungsten
28
13
Zinc
18
19
Some Major Minerals of India
Table . Major reserves and important uses of some of the major metals Major World Reserves
Major Uses
Aluminium
Australia, Guinea, Jamaica
Packaging food items, transportation, utensils, electronics
Chromium
CIS, South Africa
For making high strength steel alloys, In textile/tanning industries
Copper
U.S.A., Canada, CIS, Chile, Zambia
Electric and electronic goods, building, construction, vessels
Iron
CIS, South America, Canada, U.S.A.
Heavy machinery, steel production transportation means
Lead
North America, U.S.A., CIS
Leaded gasoline, Car batteries, paints, ammunition
Manganese
South Africa, CIS, Brazil, Gabon
For making high strength, heatresistant steel alloys
Platinum group
South Africa, CIS
Use in automobiles, catalytic converters, electronics, medical uses.
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ENVIRONMENTAL
SCIENCE
AND
ENGINEERING
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Metal
D.PARTHIBAN
Coal and lignite: West Bengal, Jharkhand, Orissa, M.P, A.P Uranium (Pitchblende or Uranite ore): Jharkhand, Andhra Pradesh (Nellore, Nalgonda), Meghalaya, Rajasthan (Ajmer). Aluminium (Bauxite ore): Jharkhand, West Bengal, Maharashtra, M.P, Tamilnadu. Iron (haematite and magnetite ore): Jharkhand, Orissa, M.P, A.P, Tamilnadu, Karnataka, Maharashtra and Goa. Copper (Copper Pyrites): Rajasthan, Bihar, Jharkhand, Karnataka, M.P, West Bengal, Andhra Pradesh and Uttaranchal.
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Gold
South Africa, CIS, Canada
Ornaments, medical use, electronic use, use in aerospace
Silver
Canada, South Africa, Mexico
Photography, electronics jewellery
Nickel
CIS, Canada, New Caledonia
Chemical industry, steel alloys
20
Environmental Effects of Extraction and Using Mineral Resources
ACID MINE DRAINAGE PROCESS
Jaduguda Uranium Mine, Jharkhand—-exposing local people to radioactive hazards. Jharia coal mines, Jharkhand—underground fire leading to land subsidence and forced displacement of people. Sukinda chromite mines, Orissa—seeping of hexavalent chromium into river causes serious health hazard, Cr6+ being highly toxic and carcinogenic. Kudremukh iron ore mine, Karnataka—causing river pollution and threat to biodiversity. East coast Bauxite mine, Orissa—Land encroachment and issue of rehabilitation unsettled. North-Eastern Coal Fields, Assam—Very high sulphur- contamination of groundwater.
Environmental Effects caused by mining activities are :
De-vegetation /Loss of biodiversity Subsidence of land: This is mainly associated with underground mining. Subsidence of mining areas often results in tilting of buildings, cracks in houses, buckling of roads, bending of rail tracks and leaking of gas from cracked pipelines leading to serious disasters. Groundwater Pollution: Sulphur, usually present as an impurity in many ores is known to get converted into sulphuric acid through microbial action, thereby making the water
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AND
4. Mine Closure - waste dumps, dismantling of buildings - surface water contamination, revegetation failure, and wind pollution.At least six major mines need a mention here which are known for causing severe problems:
SCIENCE
3. Smelting and Refining - processing of mineral concentrate by heat or electro-chemical processes.-use of toxic chemicals for processing, sulphur dioxide emissions contribute to acid rain, require high energy.
ENVIRONMENTAL
2. Mining and Milling - Ore extraction, crushing /grinding of ore, chemical concentration of ore.-wind borne dust, acid generation from waste rock, heavy metal leaching from acid mine drainage
D.PARTHIBAN
1. Exploration - Drilling, sampling. - Noise pollution, road damage, loss of vegetation.
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appetite. To meet physiological needs for growth, to supply energy, to do work, to maintain body temperature. Foods differ in the amount of the nutrients. Plants: Four crops-wheat, rice, corn, and potato make up most of the world's total food production than all other crops combined. Grains (mainly rice, wheat, and corn) provide about half the world's calories. Fruits &Vegetables are rich in vitamins, Minerals, Dietary fibre and complex carbohydrate. Livestock: Domesticated animals eg.Cattle, sheep,goat, camel,etc. People consume meat, eggs, milk, cheese, and other products of domesticated livestock. Aquaculture: Marine and fresh water food contribute to high quality protein In addition, onethird of the world's fish catch is converted into fish meal to feed livestock consumed by meat eaters. Fish and sea food contribute about 70 million metric tons of high quality protein to the world’s diet. One-third of the world's fish catch is converted into fish meal to feed livestock. Fish and sea food contribute to one fourth of the total dietary protein in Japan.
WORLD FOOD PROBLEM
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D.PARTHIBAN //
16th October is declared as the World Food Day. Food: It is a Organic matter taken to satisfy
ENGINEERING
“THE” FOOD RESOURCES
AND
SCIENCE
acidic. Some heavy metals also get leached into the groundwater and contaminate it posing health hazards. Surface water pollution: The acid mine drainage often contaminates the nearby streams and lakes. The acidic water is detrimental to many forms of aquatic life. Heavy metal pollution of water bodies near the mining areas is a common feature creating health hazards. Air pollution: In order to separate and purify the metal from other impurities in the ore, smelting is done which emits enormous quantities of air pollutants damaging the vegetation nearby and has serious environmental health impacts. The suspended particulate matter (SPM), SOx, soot, arsenic particles, cadmium, lead etc. shoot up in the atmosphere near the smelters and the public suffers from several health problems. Occupational Health Hazards: Most of the miners suffer from various respiratory and skin diseases due to constant exposure to the suspended particulate matter and toxic substances. Miners working in different types of mines suffer from asbestosis, silicosis, black lung disease etc.
ENVIRONMENTAL
21
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World
food problems involve complex interactions among Food production, Population growth, Poverty, Environmental effects, Economic, Political systems, and Ethics. In 1996, the World Bank estimated that more than one billion of the world's people do not have enough food to lead healthy and productive lives. Food and Agriculture Organization (FAO) estimates that about 840 million people remain hungry, though the number has been decreasing 2.5 million per year over the last eight years. The Food and Agriculture Organization (FAO) of United Nations estimated that on an average the minimum caloric intake on a global scale is 2,500 calories/day.
Undernourishment: People receiving less than 90% of these minimum dietary calories
still undernourished. Malnutrition: The dietary condition caused by an insufficiency of one or more nutrients in the diet. The two most common forms of PEM, Marasmus and kwashiorkor Overnutrition: In richer countries, the most common dietary problem is too many calories. The average daily calorific intake in North America and Europe is above 3,500 calories. Overnutrition contributes to overweight ,high blood pressure,heart attack, and other cardiovascular diseases.
Balanced Diet: A balanced diet includes a variety of foods from all 5 food
KWASHIORKAR
MARASMUS
THE EFFECTS OF AGRICULTURE ON THE ENVIRONMENT
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ENVIRONMENTAL
SCIENCE
AND
groups.(Grains,Vegetables,Fruits, Meat & dairy products, Sugar & Fats). It should provide enough calories to ensure desirable weight and should include all the necessary daily nutrients. About 50% of your calories should come from complex carbohydrates. About 20% should come from proteins. About 30% should come from fats.
D.PARTHIBAN
India is the third largest producer of staple crops; an estimated 300 million Indians are
//
ENGINEERING
are called undernourished and if it is less than 80% they are said to be seriously undernourished. As a result, the body begins to break down its own stored fats and proteins. Children in this category are suffer from permanently stunted growth , mental retardation, and other developmental disorders. Every year 40 million people (fifty percent of which are young children between 1 to 5 years) die of undernourishment and malnutrition.
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A.
Local Effects: These occur at or near the site of farming. It includes soil erosion and increase in sedimentation. It destroys aquatic life. B. Regional Effects: It includes deforestation, desertification, large scales pollution, fertility of the soil is also affected. C. Global Effects: These include climatic changes as well as potentially extensive changes in chemical cycles. Overgrazing: Livestock wealth plays a crucial role in the rural life of our country. The live stock grazing on a particular piece of grassland is called as Overgrazing. Impact of Overgrazing:
More food
Supported a larger population
Longer life expectancy
Higher standard of living Formation cities
of villages ,towns and
Destruction of wild life habitats from clearing forests and grasslands Killing of wild animals feeding on grass and crops Fertile land turn into desert by live stock overgrazing Soil eroded into lakes and streams Towns and cities concentrated wastes and pollution
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// ENGINEERING AND
Disadvantages AGRICULTURAL REVOLUTION
Advantages
SCIENCE
It makes use of hybrid seeds of selected and single crop variety, high-tech equipments and lots of energy subsidies , fertilizers, pesticides and irrigation water.Impacts related to high yielding varieties (HYV): The uses of HYVs encourage monoculture i.e. the same genotype is grown over vast areas. In case of an attack by some pathogen, there is total devastation of the crop by the disease due to exactly uniform conditions, which help in rapid spread of the disease. Without the availability of proper toxicological information on the chemicals (fertilizer,pesticides) they are used extensively into the environment.
ENVIRONMENTAL
EFFECT OF MODERN AGRICULTURE:
D.PARTHIBAN
Land Degradation, Soil Erosion, Loss of useful species, overgrazing vast areas in Arunachal Pradesh and Meghalaya are getting invaded by thorny bushes, weeds etc. of low fodder value.
S.NO 1 2 3
TYPE OF PESTICIDE Insecticides Weedicides/herbicides Fungicides
4
Rodenticides
5
Molluscicides
6
Nematicides
USED TO CONTROL insects weeds fungi Rodents molluscs nematodes
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// ENVIRONMENTAL
Classification # 1
SCIENCE
AND
Fertilizer – pesticide Problems: Fertilisers are defined as materials having definite chemical composition that supply plant nutrients. Fertilzers are added to the soil to restore and enhance the soil fertility to improve the quality and quantity of plant growth. Most of the chemical fertilizers used in modern agriculture have nitrogen, phosphorus and potassium (N, P, K) which are essential macronutrients. The excess fertilizers which are not taken up by the plants are leached out of the soil and contaminate the subsoil water sources. They pass through the different trophic levels of the food chain. Nitrogenous fertilizers applied in the fields often leach deep into the soil and ultimately contaminate the ground water. High concentrations of nitrates consumed through drinking water and leafy vegetables are reduced to nitrites by bacterial action in the intestines. when their concentration exceeds 25 mg/L, they become the cause of a serious health hazard. On reaching blood stream it becomes attached to haemoglobin forming a complex methaemoglobin which reduces the oxygen carrying capacity of the blood and produces a condition known as "Blue Baby Syndrome" or methaemoglobinemia in young babies. In adult humans, gastric cancer is caused in case these nitrates are further converted into amines and nitrosoamines. Large proportion of nitrogen and phosphorus used in crop fields is washed off and alongwith runoff water reach the water bodies causing over nourishment of the lakes, a process known as Eutrophication (eu=more, trophic=nutrition). Due to eutrophication the lakes get invaded by algal blooms. These algal species grow very fast by rapidly using up the nutrients. They are often toxic and badly affect the food chain. The algal species quickly complete their life cycle and die thereby adding a lot of dead organic matter. The fishes are also killed and there is a lot of dead matter that starts getting decomposed. Oxygen is consumed in the process of decomposition and very soon the water gets depleted of dissolved oxygen. This further affects aquatic fauna and ultimately anaerobic conditions are created where only pathogenic anaerobic bacteria can survive, thus, due to excessive use of fertilizers in the agricultural fields the lake ecosystem gets degraded. Pesticide Problems: The chemical compounds that are used for the control of pests are called Pesticides Pest: Any organism that causes an economic loss or damage to the physical well being of the plant is a pest.
D.PARTHIBAN
24
ENGINEERING
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Classification # 2
Dieldrin
on bio-amplication in predatory birds affects the calcium metabolism and as a result the eggs laid by these birds have thin shells that are unable to bear the weight of the incubating birds resulting in reproductive failure.
High
concentration of DDT (Dichloro Diphenyl trichloroethane) in human beings is suspected to result in cerebral haemorrhage, hypertension, cancer, liver damage etc.
Pesticides contribute to ecological imbalance by upsetting the predatory – prey population. Prolonged use of pesticides produces pesticide resistant pests called “Super pests".
DDT
and Fragile Eggshells : During 1960s, several predatory bird species including bald eagles, peregrine falcons, osprey and brown pelicans suddenly disappeared from territories in eastern North America. Studies carried out by biologists revealed that eggs laid down by these predatory birds had thin, fragile shells that broke before hatching. PERSISTENT ORGANIC INSECTICIDES Insecticide used on corn, potatoes, cotton and for ALDRIN termite control Insecticide used on vegetables, small grains, maize, CLORDANE sugarcane, fruits, nuts and cotton Insecticide used on cotton, corn, potatoes and for DIELDRIN termite control Insecticide-primarily used for disease vector control DDT Insecticide used on cotton, grains and also used as ENDTRIN Rodenticides
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// ENGINEERING
the most effective herbicides are the compounds of 2,4-D (2,4dichlorophenoxyacetic acid).Organochlorines like DDT , dieldrin, aldrin, are hazardous because of their persistent* nature. Their concentration increases as it moves along the food chain comprosing aquatic plants, fish, predatory birds/man.
AND
Among
SCIENCE
1 pesticide is sprayed to agricultural field thro helicopter, tractor and hand spray
D.PARTHIBAN
Organochlorines – DDT , heptachlor , dieldrin, aldrin, endrin Organophosphates – Parathion, Malathion and dimethoate. Organocarbomates – Phenyl carbamates , Thiocarbamates Inorganic insecticides – Arsenic and sulphur compounds.
ENVIRONMENTAL
1) 2) 3) 4)
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HEXACHLOROBENZENE HEPTACHLOR MIREX
26
Fungicide used for the treatment of seeds and also used as industrial chemical Insecticide used against soil insects, termites and grasshoppers Insecticide used to kill ants, termites and also used as fire retardant
“THE” ENERGY RESOURCES
Energy: Energy is the physical quantity, which can manifest itself as heat, as mechanical work, as motion and in the binding of matter by nuclear or chemical forces. The two laws of thermodynamics describe the behavior of energy: First law: states that energy may be transformed from one form to the other, but cannot be created or destroyed: Second law states that because some energy is always dispersed into unavailable heat energy, no spontaneous transformation of energy from one to other form (light to protoplasm, for example) is 100 per cent efficient.
WORLDWIDE COMMERCIAL ENERGY PRODUCTION
Gas, 23%
Nuclear,solar wind,hydro, 9%
Classification of energy sources
Renewable Energy Resources Non-Renewable Energy Resources
RENEWABLE ENERGY RESOURCES Renewable energy are such sources as the sun, wind, water, agricultural residue, firewood, and animal dung which do not exhaust. Measurement of Energy / Units of Energy Abbreviation
Name
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ENVIRONMENTAL
SCIENCE
Wood,peat, charcoal, manure, 6%
AND
Oil, 36%
ENGINEERING
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Coal, 26%
D.PARTHIBAN
Page: 1) 2) 3) 4) 5) 6)
J BTU Cal erg KWh MWd
27
Joule Standard SI Unit of Energy British Thermal Unit Calories Erg Kilowatt/hour Megawatt/day
WORLD ENERGY CONSUMPTION
17% BOIMASS 7% NUCLEAR 7% HYDRO POWER
12% SOLAR
Sun is an inexhaustible and pollution free source of energy. Solar equipments have been developed to harness sun-rays to heat water, cook meals, and light our houses. The solar energy originates from the thermonuclear fusion reaction taking place in the Sun. It is one of the important non-conventional energy sources. Solar energy being non- polluting and non-deplets is considered as renewable energy and thus fills into the principle of sustainability. But only 0.25 to 0.5 % of the solar energy reaching the earth is utilized for photosynthesis. Utilization of solar energy is to gain popularity among the masses due to expensive nature. In India, solar photovoltaic systems are being installed by Department of Non- Conventional energy resources for lighting, running of TV sets, water pumping etc. Solar cells are used to convert the impinging solar radiation into electricity The reliability of the operation is extraordinarily high. Even under severe space conditions a maintenance free life span of ten or more years has been achieved. Only disadvantage is that, its cost is very high. For a solar power station with a capacity of 1000 Mw, a land of surface of about 12 km2 is required. Solar energy is currently being used to generate electricity using three technologies:
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// ENGINEERING AND
I.SOLAR ENERGY:
SCIENCE
19% OIL
ENVIRONMENTAL
13% COAL
22% NATURAL GAS
D.PARTHIBAN
3% WIND
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Direct Heating process, Solar photo-voltaic cells, Solar thermal process.
Direct Heating method Plate collectors, solar panels, reflectors, concentrators etc a are re used to collect and concentrate solar energy. Solar energy increases the temperature. This technology is being used in solar cookers, solar ovens, solar dryers, solar water heaters, solar distillation etc.
1. 2. 3. 4. 5. 6. 7.
Solar energy is free and it is available locally in abundance. Solar energy is pollution free. Systems are easy to install, generate and maintain. System can be specifically designed according to individual requirements. Supply of hot water is instant and un interrupted Recurring fuel costs are zero Heating 100 liters of water to 60o c by solar system results in an energy saving of 1200-1500 1200 units (kilowatts hours) of electricity per year.
II.HYDRO ELECTRICAL ENERGY
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AND SCIENCE
Advantages of solar energy
ENVIRONMENTAL
fig-solar solar cel Solar thermal process method Solar energy is converted into solar thermal energy. There are several methods to convert solar energy e into thermal energy, the common one is to use a member of heliostats or mirrors and to focus them over a absorber some devices based upon solar thermal energy are - solar cookers, solar water heaters, solar air heaters, solar green ho houses, solar huts etc.
ENGINEERING
//
D.PARTHIBAN
Solar Photo-voltaic Cells (SPVC) method Solar photovoltaic technology is used for direct conversion of solar radiation into electricity using solar cells. SPVC are thin wafers of silicon,(semi conductors ), gallium, arsenide or cadmium telluride. When light falls over the semi conductor surface a part of this light is absorbed and a voltage is generated. This is only 0.5 volts. Therefore, a large number of photovoltaic cells are connected both in parallel and in series to form PV model. Solar cells are use used d in street lighting, domestic lighting, community lighting, small power plans and operation of railway signals.
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29
Electricity produces from waterpower is known as hydroelectric energy. The potential energy of falling water captured and converted to mechanical energy by water wheel powered the start of industrial revolution.
Large Scale Hydro power:
in this case a high dam is built across a large river to create a reservoir, water is allowed to flow to through huge pipes laid along the steep hill slopes (falling) at controlled rates, thus spinning turbines ( prime movers) and in turn generators producing electricity. Small hydropower: In this case a low dam with no reservoir (or only a small one) is built across a small stream and the water used to spin turbine to produce electricity. Pumped Storage hydropower: In this case the surplus electricity conventional power plant is used to lift water from a lake or tail race to another reservoir at a higher elevator, water in the upper reservoir is released to spin the turbine for generating electricity
Hydropower is an economical, renewable and non-polluting source of energy. It includes construction of dams to produce the waterfalls that fall on power turbines.
UTILIZATION OF HYDRO POWER* 7% of the world’s total commercial energy, D.PARTHIBAN
20% of the world’s electricity. 99% of the electricity in Norway, 75% of the electricity in New Zealand 43% of the electricity in india. 50% of the electricity in developing countries
India was able to generate 6.9 thousand MW of hydro electricity, contributing 42% of the total power generation capacity at the end of 4 th plan.
But, the amount of hydropower generation decreased to 25% by the end of Eighth plan due to increase in demand.
The hydropower potential of India is estimated to be 4 X 10 11 k w /hours.
Hydropower in tropical countries is a major emitter of green house gases. This occurs because reservoirs that power the dams can trap rotting vegetation, which can emit green house gases such as Carbon dioxide and Methane. (According to a study by world commission on Dams)
Moderate to high net energy High efficiency (80%) Low cost electricity
HYDRO POWER GENERATION
Advantages of and disadvantages of hydropower generation
ADVANTAGES
DISADVANTAGES High construction cost Coverts habitat
land
habitat
AND
India decided to give importance for the generation of hydro electricity in 1 st Five Year plan.
ENVIRONMENTAL
SCIENCE
*data based on survey conducted in the year-2001
ENGINEERING
//
25% of the electricity in China.
to
lake
Floods natural areas.
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Provides irrigation
water
for
year year-round
30
High carbon dioxide emission from biomass decay in shallow tropical reservoir
Long life span
High environmental impact
No carbon dioxide emission
Danger of collapse
Reservoir is useful for fishing and recreation.
Decreases fish harvest dam
May provide flood control
Uproots People.
below
Hydel power has several advantages such as: A. It is a clean source of energy. B. It provides irrigation facilities. C. It provides drinking water to people living in desert area
//
In some regions of the earth this molten material sometimes breaks through the earth's crust and produces volcanoes. In other regions, th the e hot material is close enough to the earth's surface to heat the underground water trapped by impermeable rock and form steam. Geysers and hot springs are natural areas where hot water and steam come to the surface. In such areas geo geothermal thermal energy is tapped by drilling wells to obtain steam. At present, geothermal energy is only practical in areas where the molten mass is
ENGINEERING
AND
The availability of geothermal energy depends on geographical regions. The earth contains large amounts of geothermal energy with temperature as high as 4400°C.This energy comes from magma, molten rock material beneath the surface of the earth or from radioactive decay of thorium, potassium and uranium dispersed throughout the earth's interior.
ENVIRONMENTAL
SCIENCE
D.PARTHIBAN
III.GEO-THERMAL THERMAL ENERGY:
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near the surface.
IV.WIND POWER: High-speed speed winds (kinetic energy) have a great capacity to generate power (electrical energy). Wind energy is inexhaustible, cost effective, and eco eco-friendly, friendly, non-polluting non and freely available source of energy all over the day and night. The instrument inst for harnessing wind power is called wind mill.
Small windmills are in use in rural areas for power generation, pumping water and other domestic purposes, particularly in the rural areas, such as threshing, winnowing, cutting wooden logs, grinding grains and pump water etc. Wind energy can also be used for battery charging to run generators.
To generate electricity, the speed of wind should be from 10 10-20 20 km/hour, which is available on coast, mountain, certain valleys and plains. T The he force of wind rotates the wheel, which is connected to a generator or turbine for generation of electricity. It is a Fast growing technology.
Denmark, Spain, Germany USA and India are the leaders development and d more cover than 80 per cent of world capacity.
World Watch Institute (The Washington, USA) ranked India as a Wind Superpower. Wind power development in India has been rapid at selected sites. Muppandal (Tamil Nadu), has the highest concentration (400 MW) of wind farms in Asia and the third highest in the t world.
energy
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SCIENCE
wind
ENVIRONMENTAL
in
AND
ENGINEERING
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Tamil Nadu State is one of the windiest regions of the world accounting for about 10% of the total installed global wind energy capacity and over 70 per cent of the country's total
Disadvantage of wind generators are i) Noise Pollution ii) Blades may interfere with television reception or with microwave communication
ENVIRONMENTAL
SCIENCE
installed capacity. The estimated cost of setting up wind farm project comes to Rs. 35 to 45 million per MW.
AND
ENGINEERING
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D.PARTHIBAN
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V.TIDEL ENERGY The tidal movement of water has vast potential of energy. It is estimated by the National oceanographic and Atmospheric Administration (US) the tidal potential at global level is 30,00,000 MW. The tides are daily movement of large bodies of water driven by gravitational attractions between the sun, earth and moon.
In India, the tidal power potential of Ganga delta of Sunderbans (1,000 MW), Gulf of Cambay (7,000 MW) and Gulf of Kutch (1,000 MW) has been identified and India has around 9,000 MW tidal power potential.
VI.BIOMASS ENERGY
This is the energy from garbage. The garbage of houses contains waste paper, plastics and several other waste materials. It can be used to produce electricity. Biomass energy can
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ENVIRONMENTAL
SCIENCE
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ENGINEERING
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play important and vital role to meet energy crisis of the world. Biomass can be used as renewable source of energy. Plants traps solar energy and store through the process of photosynthesis in which carbon dioxide and water are transformed and form energy rich compounds. Biomass conversion is done by using non biological and biological process. Plants are the major source of biomass.
Biomass is the term used to describe the organic matter produced by photo synthesis that exists on the Earth’s surface. The source of all energy in biomass is the Sun, the biomass acting as a kind of chemical energy store. Traditionally the extraction of energy from biomass is split into three distinct categories:
Solid biomass: The use of trees, crop residues animal and human waste, house hold or industrial residues for direct combustion to provide heat.
Temperate regions: Produce wood, crop residues like straw, vegetable leaves, human and animal waste. Arid and Semi arid regions: Produce very little excess vegetation for fuel. People living in these areas are often the most affected by desertification and have differently in finding sufficient wood fuel. Humid tropical regions: Produce abundant wood supplies, crop produces, animal and human wastes, commercial industrial agro and food processing residues. Many of the world’s poorer countries are found in these regions and hence there is a high incidence of domestic biomass use. Benefits of Biomass energy: Renewable or recyclable energy source (Stored solar energy) Less waste directed to landfills.
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AND SCIENCE
Biomass resources: They are renewable energy recourses. Natural Biomass resources vary in type and content depending upon the geographical location. World’s biomass producing areas are classifieds into three distinctive regions.
ENVIRONMENTAL
Biomass use in the development world More than two billion people in the developing world use biomass for the majority of their household energy needs. Biomass is also used widely used for non-domestic appliances. Biomass is available in varying quantities through out the developing world. In recent decades, with the threat of global deforestation much focus has been given to the efficient use of biomass.
ENGINEERING
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Liquid bio-fuels: They are obtained by subjecting organic materials to one of the various chemical or physical processes to produce a usable, combustible liquid fuel. Bio fuels such as vegetable oils or ethanol are often processed from industrial or commercial residues such as biogas or from energy crops crown especially for these purposes.
D.PARTHIBAN
Biogas: it is obtained an aerobically (without air) digesting the organic material to produce ethane. Animal waste and municipal waste are two common feed stocks for anaerobic digestion.
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Decrease reliance on imported energy sources. Potential rural development and job creation. It can generate renewable electricity when the Sun is not shining and the wind is not blowing.
It is generated by fission (splitting the nucleus) and fusion (combining the small nucleus) of the atoms of certain elements such as Uranium-235. Both the processes result in the release of enormous amount of energy. Fission of 1 amu* of Uranium-235 can generate energy equivalent to that obtainable from burning of 15 metric tons of coal or about 14 barrels of crude oil. In our country atomic power station have been set up in
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AND SCIENCE
Nuclear energy is non- renewable source of energy, which is released during fission (disintegration) or fusion (union) of selected radioactive materials. Nuclear power appears to be the only hope for large scale energy requirements when fossil fuels are exhausted. The major advantage is that even small quantities of radioactive material can produce enormous amounts of energy. Example: Energy produced by a ton of U235 = 3 million tones of coal = 12 million barrels of oil. Nuclear energy has been used in: the generation of electricity in spaceships, marine vessels, chemical and food-processing industry. Nuclear fission: Nuclear fission reaction are based on the fission of U235 nuclei by thermal neutrons Environmental impact: Nuclear fission power reactors generate large quantities of radio active fission waste products, which may remain dangerous for thousand of years. In addition these are no safe disposal methods.
ENVIRONMENTAL
VII.NUCLEAR ENERGY
ENGINEERING
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Biogas is obtained by an aerobically (without air) digesting organic material to produce a combustible gas known as methane. Animal waste and municipal waste are two common feed stocks for an aerobic digestion. At present biogas technology provides an alternative source of energy in rural India for cooking. It is particularly useful for village households that have their own cattle. Through a simple process cattle dung is used to provide the gas. The residual dung is used as manure. India has world’s largest cattle population – 400 million, thus offering tremendous potential for biogas plants. Biogas production has the capacity to provide us with about half of our energy needs either burned for electricity production or piped into current gas lines for use. It just has to be done and made a priority. Though about 3.71 million biogas plants in India up to March 2003 are successfully in operation but still it is utilizing only 31% of the total estimated potential of 12 million plants. The pay back period of the biogas plant is only 2 to 3 years. Rather in the case of community and industrial Biogas plants is even less. Therefore biogas electrification at Community Panchayat level is required to be implemented. A sixty cubic feet approx 2 m3 biogas plant can serve the needs of one average family. The average composition of biogas is methane 55%. Hydrogen 7.4%, Carbon dioxide 39%, Nitrogen 2.6%, Waster- traces. The average gross calorific value of the gas is 5300 kilo cals /cubic meters.
D.PARTHIBAN
BIOGAS
Energy liberation is carried out in nuclear reactors. The fissionable material decays liberating huge energy as heat, which is picked up by coolant for transfer to electric generator. Thorium and Uranium are the two naturally occurring elements which have the potential of being used as fuel in a nuclear power plant. India has reasonable deposits of natural uranium, while thorium deposits are quite vast.
D.PARTHIBAN ENVIRONMENTAL
Natural uranium consists of two isotopes, of which U235 constitutes about 0.7% of natural uranium, can be easily undergo fission in a nuclear reactor to produce energy. Thorium, a fertile material, cannot be easily fissionable in a nuclear reactor to produce energy, However, like uranium-238, thorium also gets partially converted to a fissile material uranium-233, when used as a part of nuclear fuel mix
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Advantage: Production of an enormous amount of energy from a small quantity of radioactive material. For example - One kg of Uranium (having 0.7 per cent of U235) liberates energy equivalent to 35000 kg of coal.
ENGINEERING
Tarapur (Bombay), Narora (Uttar Pradesh), Kota (Rajasthan) Kalpakkam (Tamil Nadu). to atomic mass unit, please refer Engineering Chemistry by Ravikrishnan
AND
*amu refers
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SCIENCE
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VIII.FUEL CELL
AND
Fossil fuels are the highest grade fuels, which contain nothing but hydrogen and carbon formed in the past through the effect of heat and compression on forest and other organic matter buried underneath due to landslides, earth quakes and lava.
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These are energy raw materials, which are available in limited quantity and are of greatest practical significance. These are Fossil Fuels they are organic fuel resources found in earth's crust formed due to coalification.
ENGINEERING
NON-RENEWABLE ENERGY RESOURCES:
D.PARTHIBAN
Hydrogen-oxygen fuel cell.
Majority of fossil fuels are being used in Transportation Industries heating Generation of electricity.
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ENVIRONMENTAL
Fossils fuels (oil, coal, natural gas) are energy rich substances that have formed from the residues of dead organisms lived 200 to 500 million years ago. This matter was buried under layers of sediment and converted by heat and pressure into coal, oil and natural gas. Fossil fuels largely consist of hydrocarbons, which are compounds of hydrogen and carbon. Some fossils fuel also contains smaller quantities of other compounds. Most common and important fossil fuels are: Coal,lignite = solid fuel Petroleum = liquid fuel Natural gas = gas fuel
SCIENCE
FOSSILS FUELS
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Manufacture of gasoline Manufacture of diesel Manufacture of jet fuel Once we discovered the fossil fuel we began consuming them at an increasing rate. From 1860 to 1970, total oil production was 227 billion barrels (1 barrel=159 lts). 50% of this total was extracted during the first 100 years, while the next 50% was extracted in next 10 years.
90% carbon content 85% carbon content 70% carbon content
The present annual extraction rate of coal is about 3000 million metric tones, at this rate coal reserves may lasts for about 200 hundred years and if its use is increased by 2% per year then it will last for another 65 years. Advantages Low cost (with huge substitutes) Mining and combustion technology well developed High net energy yield Disadvantages land, air water pollution Very high environmental impact Releases radio active particles and mercury into air. Severe threat to human health High CO2 emission Limited availability supplies (225-900years)
____________________________________________ PETROLEUM ___________________________________________
Significance of petroleum over coal is that its greater energy content than coal. Petroleum is cleaner fuel when compared to wood or coal, since it burns completely and leaves no residue.
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= = =
ENGINEERING
Mainly, there are three types of coal: Anthracite or hard coal Bituminous or soft coal Lignite or brown coal
AND
SCIENCE
Nearly 27,350 billion metric tones of known coal deposits occur on our planet. 56% of world coal reserves are located in Russia, 28% of world coal is located in USA and Canada. 5% of world coal are located India. The major coal producing states in India are. West Bengal, Jharkhand, Orissa, Andhra Pradesh, Madhya Pradesh Maharastra
ENVIRONMENTAL
D.PARTHIBAN
____________________________________________COAL_________________________________________________
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ADVANTAGES
Ample supplies (125 years)
High net energy yield
Low cost ( with huge subsidies)
Less air pollution than other fossil FUEL
Moderate environmental import
Easily transported by pipelines
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D.PARTHIBAN
Natural gas mainly consists of Methane (CH4) along with other inflammable gases like Ethane and propane. Natural gas is least polluting due to its low Sulphur content and hence is clearest source of energy. It is used both for domestic and industrial purposes. Natural gas is used as : a source of hydrogen gas in fertilizing industry as a fuel in thermal plants for generating electricity as a source of carbon in tyre industry. The total natural gas reserves of the world is about 600 000 billion meters, Annual production of natural gas is about 1250 billion cubic meters Hence it is expected to last for about 50-100 years. In India gas reserves are found in Tripura, Jaisalmer, Off shore areas of Bombay and Off shore areas Krishna-Godavari Delta.
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ENGINEERING
__________________________________________NATURAL GAS_____________________________________________
AND
SCIENCE
There are 13 countries in the world having 67% of the petroleum reserves which together form the OPEC (Organization of petroleum exporting countries). About 40% of the total energy consumed in the entire world is now contributed by oil. Saudi Arabia oil producing has ¼th of the world oil reserves. Six regions in the world are rich in petroleum: USA, Mexico, Russia Iran Iraq Saudi Arabia The total oil reserves of our planet is about 356.2 billion metric tones Hence the existing reserves would last for about 40 – 50 years. There are little of petroleum reserves in India. It is estimated to be >1 million sq.km area. Ganga-Brahmaputra valley Gujarat Thar Desert Andaman and Nicobar Islands
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Low land use
Releases carbon dioxide when burnt
Methane ( a green house gas) can leak from pipelines
Shipped across ocean as highly explosive
Requires pipelines
Sometimes burnt off and wasted
____________________ENVIRONMENTAL EFFECTS OF USING FOSSIL FUELS__________________________
Acid rain When fossil fuels are buried, Sulphur, Nitrogen and Carbon combine with oxygen to form toxic compounds. These oxides when released into the atmosphere, they react with water form and result in the formation of Sulfuric acid, Nitric acid and Carbonic acid. This leads to acid rain
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ENVIRONMENTAL
Global warming Carbon dioxide is a major by product of fossil combustion and this gas is known as green hour gas. Green hour gas absorbs solar heat reflected off the earth’s surface and retains this heat, keeping the Earth warm and habitats for living organisms. Rapid industrialization between 19th and 20th centuries however has resulted in increasing fossils fuel emissions, raining the percentage of carbon dioxide by about 28%. This drastic increase has led to global warming that could cause environmental problems, including disrupted weather patterns and polar ice cap melting.
SCIENCE
AND
Ash particles Ash particles are the unburnt fuel particle. Petro and natural gas generate less ash particles than coal, diesel or gasoline. They may cause lungs problem
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Non renewable resources
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DISADVANTAGES
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“THE” LAND RESOURCES Land is a major constituent of the lithosphere. It is an important source of many materials essential to man and other organisms. It provides essential medium for development of agriculture, forestry etc. The per-capita land availability in different continents of the world varies widely. Area : Land forms about one fifth of the earth's surface covering about 13,393 million hectares.
About 36.6 % of the land area is occupied by human dwellings, factories, roads, railways, deserts, mountains, rocks, glaciers and polar ice marshes. About 30 % of the total land mass in under forests. About 22 % of land is occupied by meadows and pastures. Only 11 % of land is suitable for ploughing.
Soil fertility is determined by the inorganic matter, organic matter, water and air spaces in the soil. The mineral portion of the soil consists of various mixtures of sand, silt and clay particles. SOIL TEXTURE: The physical structure of a soil is called soil texture. It depends upon the % of its mineral particles. Soil texture determines the porosity and nutritional status of the soil. There are three important textural soil types-sandy, clayey and loamy.
(i) Sandy soils: contain < 10 % each of clay and silt + remaining part is sand. Porous and well aerated,Little water holding capacity, chemically inert. Generally called light soils because of the absence of moisture. So it is unfit for plant growth.
(ii) Clayey soils: 40 % or more clay.Heavy soils because the soils are compactly packed with little aeration.small sized pores, which retain water very firmly.Clayey soils are rich in nutrients but do not support good plant growth due to poor aeration.
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// ENGINEERING
*pedo means soil
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(ii) pedo*-genesis-maturation of soil through development of humus.
SCIENCE
(i) weathering-breaking down of rock into small particles and
ENVIRONMENTAL
Soil is an organized mixture of minerals, organic material, living organisms, air and water. It deals with the origin, formation and geographic distribution of the soil. Soil is formed by two processes
D.PARTHIBAN
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(iii) Loamy soils: They contain sand, silt and clay approximately in the ratio of 2 : 2 : 1.Ideally suited for plant growth because they possess good aeration, sufficient nutritive salts and good water retaining capacity. Composition of Soil: Soil is composed of five constituents: (i) (ii) (iii) (iv) (v)
mineral matter organic matter soil water soil air living organisms.
3. Soil water: The spaces between soil particles are occupied by water or air. The water in the soil is present as capillary water, hygroscopic water, combined water and water vapour. Soil receives water either by rains or irrigation. The maximum amount of water retained per unit dry weight of soil after the stoppage of gravitational flow is called water holding capacity or field capacity of the soil.It is 25 - 35 % in loam soil.Soil moisture beyond field capacity causes water-logging. It is harmful to the plants, as it drives away soil air. 4. Soil air: Soil contains air in the pour spaces. In a good soil such as loam about 20-25 % of the total volume is soil air. The composition of soil is dependent upon air circulation or connection of the pore spaces with the soil surface. In a poorly ventilated soil concentration of O2 decreases while that of CO2 increases because of the respiration of plant roots and soil organisms.High concentration of CO2 in the soil is toxic to the soil organisms.
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It is derived from plant refuse (leaves, twigs, roots), dead bodies of organisms and their excreta(wastes). The organic matter is broken down by microbes and is converted into dark amorphous substance called humus. Humus is a very useful substance in the soil. It acts as natural fertilizer.
AND
2. Organic matter:
SCIENCE
Depending upon their size ,soil particles are of following types : Gravel [ 2.00 -5.00 mm], Coarse Sand[0.20 -2.00 mm],Fine Sand[0.02 -0.20 mm],Silt [0.002-0.02 mm],Clay[ less than 0.002 mm
ENVIRONMENTAL
Derived from the underlying parent rock by its weathering and occurs in the soil as particles. The mineral particles are irregular in outline and therefore enclose spaces called interstices for circulation of air and water.
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1. Mineral matter:
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O2 in soil is essential for humus formation, nitrification, respiration of microorganisms and activities of roots (absorption of water and mineral salts).
5.
Soil organisms:
A variety of living organisms such as bacteria, actinomycetea, fungi, algae, protozoa, nematodes, earthworms occur in the soil. The soil organisms perform following activities in the soil : Decomposition of dead organic matter- Saprophytic soil microorganisms Nitrogen fixation- Cyanobacteria. Aeration of the soil - Burrowing (earth digging) insects and worms Several soil organisms secrete mucus, which help in cementing soil particles to form soil aggregates. (5) Some microorganisms chemical substances that have stimulating effect on the growth of higher plants. (6) Some soil fungi form mycorrhizal association with the roots of higher plants and assist them in obtaining water and nutrients from the soil. (7) Several soil organisms take part in biogeochemical cycles.
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Types of Indian Soils
D.PARTHIBAN
(1) (2) (3) (4)
@ @ @ @
Red Colour -iron components. Low water retention capacity. Poor in N,P,K and organic matter. Andhra Pradesh, Tamilnadu,Bihar, Orissa, U.P. ,West Bengal.
AND
Red soils:
ENGINEERING
Soils of India are classified into six major types based on their nature and composition
Good for cotton and sugarcane cultivation. Maharashtra, Mysore and Madhya Pradesh.
Skeletal soils: @ @ @ @ @
Also called as Mountain soil Altitude between 2000 m and 3000 m. Undergoes land slides and snowfall. North-western hills or the Aravallis Used for forestry and growing potatoes, and subtropical fruits.
Desert soils: @
Annual rainfall is less than 50 centimetres.
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ENVIRONMENTAL
@ @
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Black soils:
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These soils cover 1.4 lakh square kilometres. Desert soils can be reclaimed through good irrigation. Rajasthan, semi-desert areas of Kutch.
Land Degradation: Any change in the land that reduces its condition or quality and hence its productivity or productive potential is called “land degradation”
Wind and high velocity flowing water
2
Salination
Improper irrigation and faulty drainage system
3
Acidification
Leaching of soluble chemical substances
4
Deposition of salt
Flood and water logging
5
Developmental activities such as.
Construction of dams, roads, railways, urban encroachment, industrialization and mining
Soil Erosion
S.NO
POINTS TO BE REMEMBERED
1
It takes up to 300 years for 1 inch of agricultural topsoil to form, soil that is lost is Nutrient-rich topsoil erosion
2
The effect of these losses of topsoil on the farm is devastating. Eroded soils can become useless for crop production.
3
As wind and water remove the finer particles, the subsoil that is left is coarser, with less organic matter to break up the soil, and more fertilizers are needed to make it support plant growth.
4
Erosion is less severe with crops such as wheat (covers the ground uniformly), than with crops such as corn and tobacco (grown in rows)
5
The factors enhancing soil erosion:@ Intensity of rainfall @Slope of the ground @Soil type @Vegetal cover area @ Uncontrolled grazing by cattle etc
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Soil erosion
ENGINEERING
1
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REASON
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FACTOR
ENVIRONMENTAL
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Factors affecting the land resources are:
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Desertification
Desertification is a slow process of land degradation that leads to desert formation.
Erosion of the top fertile soil leads to in loss of soil productivity and formation of deserts.
Many deserts in the world are a result of human activities.
The destruction of natural vegetation results in accelerated soil erosion due to the removal of the vegetation cover.
The Thar desert in India was formed by destroying thousands of hectares productive land. Excessive grazing by livestock is another factor resulting in desertification especially in Rajasthan.
energy intensive sectors and introducing energy taxes
Improving the quality of materials -to get products which are more durable, repairable and
ENVIRONMENTAL
SCIENCE
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recyclable and avoiding the use hazardous materials Reducing transportation-providing goods and services as close as possible to the consumers
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renewable substitutes.
Rate of pollution emission do not exceed assimilative capacities of the environment. Aiming to achieve complete reuse, recycle and repair Reducing fossil fuel use - maximizing the use of energy conservation measures, shrinking
ENGINEERING
Rate of use of renewable resources do not exceed regeneration rates. Rate of use of non-renewable resources do not exceed rates of development of
D.PARTHIBAN
Equitable use of Resources for sustainable Lifestyles
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CONCEPT OF AN ECOSYSTEM STRUCTURE AND FUNCTION OF AN ECOSYSTEM FOOD CHAIN, FOOD WEB,ECOLOGICAL SUCCESSION GRASSLAND,FOREST,DESERT,AQUATIC ECOSYSTEM BIODIVERSITY-GENETIC,SPECIES GENETIC,SPECIES AND ECOSYSTEM DIVERSITY VALUE OF BIODIVERSITY THREATS TO BIODVERSITY CONSERVATION OF BIODIVERSITY
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ENVIRONMENTAL
CHAPTER-III PROVIDES INFORMATION ON:
SCIENCE
AND
ENGINEERING
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D.PARTHIBAN
ۼ܃۷ ܂െ ǣ ۳۱܂܁܇܁۽۳ۼۯۻ۲۰۷۽۲۷܄۳܁܀۷܇܂
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UNIT – 2 ECOSYSTEM AND BIODIVERSITY
Components of Environment
Introduction Classification of Environment Components of Environment Environment, Ecology and Ecosystem
CLASSIFICATION OF ENVIRONMENT
SCIENCE
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Physical environment Cultural environment Biological environment
COMPONENTS OF ENVIRONMENT Classification 1
Biotic Components 1) 2) 3)
Producers Consumers Decomposers
Abiotic Components 1) Water 2) Air 3) Land
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ENVIRONMENTAL
1) 2) 3)
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DEFINITION 1 Environment can be defined as the natural surroundings of that organism which directly or indirectly influences the growth and development of the organism. DEFINITION 2 Environment is defined as the surroundings in which an organization operates including air, water, land and natural resources, flora, fauna, humans and their inter relations” DEFINITION 3 Environment is the sum total of all living and non living factors that compose the surroundings of man.
ENGINEERING
Every organism is surrounded by other organisms, plants, water, air, light, land etc. These surroundings of the organism, all the living and non-living things constitute its environment.
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INTRODUCTION
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Classification 2 1. 2. 3. 4. 5.
Hydrosphere(Water) Atmosphere(Air) Lithosphere(Land) Biosphere(Flora/Fauna/Microbes) Anthrosphere (man made things)
ENVIRONMENT, ECOLOGY AND ECOSYSTEM
CAUSES OF SUCCESSION Ecologists have recognized the following three primary causes of succession: 1. Initiating causes: These are climatic as well as biotic in nature. The climatic causes include factors such as erosion and deposits, wind, fire, etc., which are caused by lightening or volcanic: activity. The biotic causes include various activities of organisms. All these causes produce the bare areas or destroy the existing populations in an area. 2. Continuing causes: These are processes as migration, aggregation, competition, reaction, etc., which cause successive waves of populations as a result of changes, chiefly in the soil features of the area. 3. Stabilizing causes: These include factors such as climate of the area which result in the stabilization of the community. BASIC TYPES OF SUCCESSION 1. Primary succession. @
If an area in any of the basic environments (such as terrestrial, fresh-water or marine) is colonized by organisms for the first time, the succession is called primary succession.
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D.PARTHIBAN //
In a particular area, one community of species may be replaced by another community; the progressive replacement of one community by another till the development of stable community in a particular area is called “ecological succession”
ENGINEERING
ECOLOGICAL SUCCESSION
AND
@
SCIENCE
@
Environment, Ecology and Ecosystem are three different terms. But they are inter related. The natural surroundings of an organism, both living and physical are its environment. Let’s say you are an organism. Light, Water, Air, Land etc are your physical surroundings. Humans, Rats, Lizards, Dogs etc are your living surroundings. They are your environment. The ecology that takes place in a defined area is called ecosystem. Say your relation with water, light, humans, dogs etc in a city, or in a forest, sea etc.
ENVIRONMENTAL
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ENERGY FLOW AND NUTRIENT CYLCING IN ECOSYSTEM
The two major functions within an ecosystem are the transfer of energy through, and the recycling of nutrients within the ecosystem.
ENERGY FLOWS I N ECOSYSTEMS PHOTOSYNTHESIS
Photosynthesis (or phototrophism) is the process, by which light energy from the sun is absorbed by plants, blue-green algae and certain bacteria. It is then used to produce new plant cell material, which forms the food source for plant eating animals (herbivores).
Plants are able to convert light energy and inorganic substances (carbon dioxide, water and various mineral nutrients) into carbon based organic molecules through the process of photosynthesis, hence they are called phototrophs or autotrophs (‘self-feeders’).
In a plant, most photosynthesis is carried out by the leaves, and in order for the process to occur they must contain “Chlorophyll”, which is able to absorb energy from sunlight. The plant also
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// ENGINEERING
2. Succession in xeric habitat Xerosere or xerarch succession begins on exposed parent rocks (lithosere) or dry sand (psammosere).
AND
1. Hydrarch succession or hydrosere in which a pond and its community are converted into a land community.
SCIENCE
Some examples of succession:
ENVIRONMENTAL
Thus, primary succession begins on a sterile area (an area not occupied previously by a community), such as newly exposed rock or sand dune where the conditions of existence may not be favorable initially. 1. Secondary succession. @ If the area under colonization has been cleared by whatsoever agency (such as burning, grazing, clearing, felling of trees, sudden change in climatic factors, etc.) of the previous plants, it is called secondary succession. @ Usually the rate of secondary' succession is faster than that of primary succession because of better nutrient and other conditions in area previously under plant cover. 2. Autogenic succession. @ After the succession has begun, in most of the cases, it is the community itself (as a result of its reactions with the environment) modifies its own environment and, thus, causing its own replacement by new communities. This course of succession is known as autogenic succession. 3. Allogenic succession. @ In some cases replacement of one community by another is largely due to forces other than the effects of communities on the environment. This is called allogenic succession and it may occur in a highly disturbed or eroded area or in ponds where nutrients and pollutants enter from outside and modify the environment and in turn the communities.
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requires carbon dioxide, from the atmosphere, and water from the soil. As a result of the process, and carbohydrates are produced.
Glucose
Oxygen
6O2
+
6H2O
Water
The carbohydrates produced by photosynthesis are: Combined with elements such as nitrogen, phosphorous and sulphur to produce proteins and nucleic acids. Converted into starch and stored in the plant. Converted into cellulose (the main plant structural material). Used by the plant for respiration i.e. biochemical processes, cell maintenance and growth. The factors which affect the rate of photosynthesis are temperature, light intensity, carbon dioxide concentration and the availability of water.
ENERGY FLOW THROUGH AN ECOSYSTEM
The energy produced by photosynthesis will pass through the food chains and food webs of an ecosystem, with some of it being stored as chemical energy in plant and animal tissue. Some of it will be lost from the system, as respiration (heat energy) and excreta products. Energy is lost at each level in the food chain, with the average efficiency of transfer from plants to herbivores being about 10 per cent, and about 20 per cent from animal. As a result of the loss of energy at each transfer between trophic levels, ecosystems are usually limited to three or four trophic levels. The actual number will depend upon the size of the initial autotrophy (producer) biomass, and the efficiency of energy transfer between the trophic levels.
NUTRIENT (GASEOUS AND BIOGEOCHEMI CAL) CYCLES
D.PARTHIBAN
Water
+
//
C6H12O6
ENGINEERING
Carbon Dioxide
12 H2O →
AND
+
SCIENCE
6CO2
The nutrients, or elements used by all organisms for growth and reproduction, are termed essential elements or macronutrients, and include
Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), Phosphorus (P), Sodium (Na),
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ENVIRONMENTAL
MACRONUTRIENTS:
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Sulphur (S), Chlorine (Cl), Potassium (K), Calcium (Ca) Magnesium (Mg).
MICRONUTRIENTS: Other elements are also required for growth of a plant. They are called trace elements or micronutrients, It includes
Iron (Fe), Manganese (Mn), Copper (Cu), Zinc (Zn) Cobalt (Co)
The two types of cycle are interrelated, as nutrients pass from abiotic nutrient stores, such as the soil and the atmosphere, into biotic, plant and anim animal al stores (the biomass). The nutrients are then recycled, within the ecosystem, following death and decomposition.
All living things are composed mainly of water, but most of the water on Earth lies in the environment (e.g. in lakes, oceans, streams, and the air). The movement of water from the physical environment, and through the biological environment is driven by the sun. In the physical environment, the sun radiates the Earth's surface with heat, evaporating the water, slowly turning liquid water to water vapor, gaseous water. As a gas, water rises from the ground, the surface of streams, lakes, but water mainly rises from our oceans. Once in the air, air currents move the gaseous water around the Earth. But when molecules of water hits a particle, or when temperatures and pressures reach the point where water liquefied or even solidifies, water begins to condense. condense As water
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ENVIRONMENTAL
___________________________________________ ___________________________________________WATER CYCLE_________________________________________ _________________________________________
SCIENCE
AND
Bio-Geo Geo-Chemical Cycle- Notes: 1
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From the atmosphere through various gaseous cycles or in precipitation, or From the soil via the weathering of parent rock, Through several biogeochemical or Sedimentary cycles.
ENGINEERING
D.PARTHIBAN
The nutrients required by plants are obtained as inputs
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condenses, it forms into rain or snow, thus the water begins to fall to the ground as it is now too heavy to remain in the air. As the water strikes the ground, some of it seeps into the soil, gathering within water tables under the earth. But the he majority of the water runs across the ground, slowly collecting until streams, then rivers form. Where the ground has large divots, lakes form. But eventually, most of the water again reaches the oceans. But the biological environment lives along side of the physical environment. Along this route, organisms live in, bath in, and drink the water, taking water into their bodies. This is important for many organisms, but it is especially important to those who live on land. Terrestrial organisms generally lose tremendous amounts of water, as it evaporates from their bodies. All organisms lose some water as they remove waste from their bodies
___________________________________________CARBON CYCLE_________________________________________
Earth's atmosphere contains 0.035%
Photosynthesis takes carbon dioxide and water er and produces carbohydrates and oxygen. The outputs of respiration are the inputs of photosynthesis, and the outputs of photosynthesis are the inputs of respiration. These The reactions are also complementary to each other. other Photosynthesis takes energy from tthe he sun and stores it in the carbon-carbon carbon bonds of carbohydrates;
Respiration releases that energy. Both plants and animals carry on respiration, but only plants (and other producers) can carry on photosynthesis.
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AND
Respiration takes carbohydrates and oxygen and reduces them to produce carbon dioxide, water, and energy.
SCIENCE
The key reactions are respiration and
ENVIRONMENTAL
photosynthesis.
ENGINEERING
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carbon dioxide
D.PARTHIBAN
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through photosynthesis.
Carbon returns to the physical environment in a number of ways. Both plants and animals
respire, so they release CO2 during respiration. Another route of CO2 back to the physical environment occurs through the death of plants and animals. When organisms die, decomposers consume their bodies. In the process, some of the carbon returns to the physical environment by way of fossilization.
Some of it remains in tthe he biological environment as other organisms eat the decomposers.
ENVIRONMENTAL
SCIENCE
AND
But by far, most of the carbon returns to the physical environment through the respiration of CO2.
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On land and in the water, plants take up carbon dioxide and convert it into carbohydrates
ENGINEERING
dissolves readily in water. It may precipitate as a solid rock known as calcium carbonate (limestone). Corals and algae encourage this reaction and build up limestone reefs in the process.
D.PARTHIBAN
The chief reservoirs for carbon dioxid dioxide e are in the oceans and in rock. Carbon dioxide
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C. D. E.
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AND
B.
If you look back at the carbon cycle, you will see that we have also described the oxygen cycle, since these atoms often are combined. Oxygen is present in the carbon dioxide, in the carbohydrates, in water, and as a molecule of two oxygen atoms. Oxygen is released to the atmosphere by autotrophs during photosynthesis and taken up by both autotrophs and heterotrophs during respiration. In fact, all of the oxygen in the atmosphere is biogenic; that is, it was released from water through photosynthesis by autotrophs. It took about 2 billion years for autotrophs (mostly cyanobacteria) to raise the oxygen content of the atmosphere to the 21% that it is today; this opened the door for complex organisms such as multicellular animals, which need a lot of oxygen.
SCIENCE
A.
ENVIRONMENTAL
___________________________________________OXYGEN CYCLE______________________________________
ENGINEERING
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D.PARTHIBAN
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______________________________________NITROGEN CYCLE________________________________________ CYCLE______________________________
ENVIRONMENTAL
SCIENCE
AND
This process is called nitrification nitrification. Some plants can use NO3-,, consuming nitrate and making proteins. Some soil bacteria, ho however, takes NO3-,, and converts it into N2, returning nitrogen gas back into the atmosphere. This last process is called denitrification,, because it breaks nitrate apart.
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Some soil bacteria does not convert NH3 into proteins, but they make nitrate NO3NO3 instead.
ENGINEERING
Nitrogen makes up 79% of Earth's atmosphere, but most organisms can not use nitrogen gas (N2). N2 enters the trophic system through a process called nitrogen fixation. Bacteria found on the roots of some plants can fix N2 to organic molecules, making proteins. prot Again, animals get their nitrogen by eating plants. But after this point, the nitrogen cycle gets far more complicated than the carbon cycle. Animals releases nitrogen in their urine. Fish releases NH3, but NH3 when concentrated, is poisonous to liv living ing organisms. So organisms must dilute NH3 with a lot of water. Living in water, fish have no problem with these requirements, but terrestrial animals have problems. They convert NH3 into urine, or another chemical that is not as poisonous as NH3. The pro process cess of releases NH3 is called ammonification. Because NH3 is poisonous, most of the NH3 which is released is untouchable. But soil bacteria have the ability to assimilate NH3 into proteins. These bacteria effectively eat the NH3, and make proteins from it.. This process is called assimilation.
D.PARTHIBAN
Proteins, nucleic acids, and other organic chem ica ls contain nitrogen, so nitrogen is a very importan t atom in biological organisms.
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D.PARTHIBAN
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ENVIRONMENTAL
SCIENCE
AND
_______________________________________PHOSPHOROUS CYCLE______________________________________
ENGINEERING
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.
The phosphorous cycle is the simplest of the cycles that we will examine. Phosphorous has only one form, phosphate, which is a phosphorous atom with 4 oxygen atoms.
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ENVIRONMENTAL
D.PARTHIBAN
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ENGINEERING
This heavy molecule (phosphates) never makes its way into the atmosphere; it is always part of an organism, dissolved in water, or in the form of rock. When rock with phosphate is exposed to water (especially water with a little acid in it), the rock is weathered out and goes into solution. Autotrophs take this phosphorous up and use it in a variety of ways. It is an important constituent of cell membranes, DNA, RNA, and, of course ATP, which, after all, stands for adenosine triphosphate. Heterotrophs (animals) obtain their phosphorous from the plants they eat, although one type of heterotroph, the fungi, excel at taking up phosphorous and may form mutualistic symbiotic relationships with plant roots. The plant gets phosphate from the fungus and gives the fungus sugars in return. Animals, by the way, may also use phosphorous as a component of bones, teeth and shells. When animals or plants die (or when animals defecate), the phosphate may be returned to the soil or water by the decomposers. There, it can be taken up by another plant and used again. This cycle will occur over and over until at last the phosphorous is lost at the bottom of the deepest parts of the ocean, where it becomes part of the sedimentary rocks forming there. Ultimately, this phosphorous will be released, if the rock is brought to the surface and weathered. Two types of animals play a unique role in the phosphorous cycle. Humans often mine rock rich in phosphorous. For instance, in Florida, which was once sea floor, there are extensive phosphate mines. The phosphate is then used as fertilizer. This mining of phosphate and use of the phosphate as fertilizer greatly accelerates the phosphorous cycle and may cause local overabundance of phosphorous, particularly in coastal regions, at the mouths of rivers, and anyplace where there is a lot of sewage released into the water (the phosphate placed on crops finds its way into our stomachs and from there to our toilets). Local abundance of phosphate can cause overgrowth of algae in the water; the algae can use up all the oxygen in the water and kill other aquatic life. This is called eutrophication. The other animals that play a unique role in the phosphorous cycle are marine birds. These birds take phosphorous containing fish out of the ocean and return to land, where they defecate. Their guano contains high levels of phosphorous and in this way marine birds return phosphorous from the ocean to the land. The guano is often mined and may form the basis of the economy in some areas.
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SCIENCE
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The macro-nutrients are C, H, O, P, K, I, N, S, Mg, Ca, etc., which have cycles with atmosphere while micro-nutrients like Cu, Fe, Co, etc., are soil based form edophic cycles. The bio-geo-chemical cycles are of two varieties – sedimentary cycles and gaseous cycles. In sedimentary cycles the main reservoir is the soil, the sedimentary and other types of rocks of earth’s crust. The gaseous cycles have their main reservoir of nutrients in the atmosphere and oceans. Examples are the oxygen, carbon, nitrogen, sulphur, etc. Both are driven by the flow of energy and both are tied up with the water cycle or the hydrologic cycle. In nutrient cycle, various chemical compounds of the main element are transferred while in hydrologic cycle a compound i.e., water is circulated as solid liquid and vapour phase. CARBON CYCLE Carbon is an essential constituent of carbohydrates, proteins, fats and a large number of organic compounds. CO2 of the atmosphere and that dissolved in the natural waters is the main source of carbon. Green plants use CO2 in the process of photosynthesis to make carbohydrates. In doing so the green plants lock the radiant energy of the sun in the synthesized food. This energy is utilized by all living beings for their own activities. The evolved oxygen by the process of photosynthesis is used for
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// ENGINEERING AND
Nutrients, unlike energy are recycled in the ecosystem. There are about 40 chemical elements considered to be essential for living organisms. Materials are in limited quantity in the earth’s system and to keep the system going continuously the only possibility is to regenerate the materials. The unique method evolved in nature is recycling materials continuously is by linking them in cyclic changes.
SCIENCE
Bio-Geo-Chemical Cycle- Notes: 2
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ENVIRONMENTAL
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most of the living things, the plants and animals. Thus all animals depend for their food on plants and animals. Thus all animals depend for their food on plants directly or indirectly. All organic compounds are also oxidized to CO2 and water, both of which are utilized by plants in the process of photosynthesis. C6H12O6 + 6O2 6CO2 + 6H2O + Free Energy
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ENVIRONMENTAL
The atmosphere and natural waters must be replenished with CO2. Most of the CO2 is returned to atmosphere and natural water by plants and animals through the process of respiration. Bacteria and fungi also return CO2 to the atmosphere and natural water into the soil by acting chemicals upon the dead plants and animals and their waste such as urine and faeces. It should also be noted that coal, petroleum, etc., are also noted that coal, petroleum, etc., are also the part of carbon cycle and are formed in nature by living organisms. Decomposition of micro-organism are very important in breaking down dead material with the release of carbon back to the carbon cycle. All the carbon of plants, herbivores, carnivores and decomposers is not respired, but some are fermented and some are stored. The carbon compounds such as methane that are lost to the food chain after fermentation are readily oxidized to CO2 by a number of reactions occurring in the atmosphere.
SCIENCE
AND
Figure 1 Carbon Cycle
ENGINEERING
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D.PARTHIBAN
The water goes down into the soil for the use of plants.
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NITROGEN CYCLE Of all the elements that plants absorb from soil, nitrogen is the most important element for plants growth. It is required for amino acids, proteins, enzymes, chlorophyll, nucleic acids and many other compounds. But the atmospheric nitrogen is not utilized directly. Nitrogen undergoes many changes in the nitrogen cycle like, nitrogen fixation, nitrogen assimilation, ammonification, nitrification, and denitrification Nitrogen fixation or conversion of free nitrogen of atmosphere into biologically acceptable form or nitrogenous compounds is referred to as nitrogen fixation. The fixation of nitrogen requires an investment of energy. Before nitrogen can be fixed, it must be activated so that the molecular nitrogen must be split into two atoms of free nitrogen. In physico-chemical process nitrogen combines with oxygen (as ozone) during lightening or electrical discharges in the clouds and produces different oxygen oxides. These nitrogen oxides get dissolved in rain water and on earth’s surface, they react with mineral compounds to form nitrates and nitrogenous compounds.
ENVIRONMENTAL
Biological nitrogen fixation is carried by some blue-green algae in the oceans, lakes and soils. Symbiotic bacteria (rhizobium) living in root nodules of leguminous plants and few other plants can fix nitrogen. Certain free living nitrogen fixing bacteria also fix nitrogen. Fixed nitrogen means nitrogen incorporated in a chemical compound that can be utilized by plants and animals. The actual fixation steps involves with two atoms of nitrogen combined with 3 atoms of hydrogen to form 2 molecules of ammonia. The activation and fixing, the two steps require a net input of 147 Kilo Calories. Once ammonia or ammonium ion appeared in the soil, it can be absorbed by the roots of plants and the nitrogen can be incorporated into amino acids and then to protein.
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2HNO3 + CaCO3 Ca(NO3)2 + CO2 + H2O
ENGINEERING
N2O5 + H2O 2HNO3
AND
2NO2 + (O) N2O5
SCIENCE
2NO + 2(O) 2NO2
D.PARTHIBAN
N2 + 2(O) electric changes 2NO
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Unlike carbon and oxygen cycles (gaseous cycles), sulphur and phosphorus cycles are sedimentary cycle. Sulphur is present normally as sulphates or sulphides. In sulphur springs and volcanic eruptions sulphur di-oxide oxide is present to some extent. Sulphur is a component of 3 amino acids. Sulphur cycle is going to be importa important nt from protein synthesis point of view. Almost all proteins contain these amino acids. Sulphur is also present in the fossil fuels which emit sulphur di-oxide, di in the automobile exhaust. Under anaerobic conditions sulphates are used to supply oxygen for sulphur organisms. In some of the sulphur bacteria elements of sulphur is precipitated. Hydrogen sulphide produced under anaerobic conditions can be oxidized to suplhur or sulphates. Sulphur di-oxide di in the atmosphere gets converted to sulphorou sulphorous s and sulphuric acid causing the acid rain problem in many urban and industrial areas. In sewers, because of anaerobic conditions, H2S is produced. This get oxidized with oxygen present in the sewer pipe and become SO2 which dissolves in water to form sulphuric ulphuric acid. Accumulation of this inside the pipe results in ‘crown corrosion’ in sewers.
Sulphur cycle links soil, water (Figure 3). Sulphur also occurs in soils and rocks as sulphides (FeS, ZnS, etc.). Except a few organisms which need organi organic c form of suplhur as amino acids and cystein,
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// ENGINEERING AND
SULPHUR CYCLE
SCIENCE
Denitrofication in conversion of nitrite and nitrate into nitrogen by Thiobacillus denitrifications, micro coccus, denitrificans, pseudomonas aerusinosa aerusinosa, etc.
ENVIRONMENTAL
Nitrogen assimilation means that the inorganic nitrates, nitrites or ammonia must be incorporated into organic compounds. Ammonification means that the dead organic remains of plants and animals and excreta creta are acted upon by bacteria, actinomycetes releasing nitrogen as ammonia. Enitrification means conversion of ammonia into nitrate by nitrosomonas, nitro coccus, in oceans and soils. Conversion of nitrite into nitrate by nitrobacter is also nitrifi nitrification.
D.PARTHIBAN
Figure 2 Nitrogen Cycle
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Functions of an ecosystem
When we consider the function of an ecosystem, we must describe the flow of energy and the cycling of nutrients. That is, we are interested in things like how much sunlight is trapped by plants in a year, how much plant material is eaten by herbivores, and how many herbivores are eaten by carnivores. Thus, the producers, the green plants, fix radiant energy and with the help of minerals (such as C, H, O, N, P, Ca, Mg, Zn, Fe, etc.) taken from their cdaphic (soil) or aerial environment (the nutrient pool) they hey build up complex organic matter (carbohydrates, fats, proteins, nucleic acids, etc.). Some ecologists prefer to refer to the green plants as converters or transducers, since in their view, the most popular and prevalent term 'producer' from energy vie view w point is somewhat misleading. T
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ENGINEERING
Sedimentary nature of sulphur cycling involves precipitation of sulphur in presence of iron, under anaerobic conditions. Sulphides of iron, co copper, pper, zinc, cadmium, cobalt are insoluble in neutral and alkalie waters and sulphur is bound to limit the amount of these elements.
AND
Green and purple photosynthetic bacteria use hydrog hydrogen of H2S as oxygen acceptor in reducing carbon-di-oxide. oxide. Green bacteria are also to oxidize sulphide to elemental sulphur, whereas purple sulphur bacteria can carry oxidation of sulphate stage. In the ecosystem sulphur is transferred from autotrophs to animals, their to decomposers and finally it returns to environment through death and decay of dead organisms.
SCIENCE
Figure 3 Sulphur Cycle
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D.PARTHIBAN
Under aerobic conditions sulphur can be
ENVIRONMENTAL
most of the organisms take sulphur as inorganic sulphates. reduced to directly sulphides.
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heir view point is that green plants produce carbohydrates and not energy and since they convert or transduce radiant energy intochemical form, they must be better called converters or transducers. The two ecological processes of energy flow and mineral cycling involving interaction between the physico-chemical environment and the biotic communities, may be considered the 'heart' of ecosystem dynamics. In an ecosystem, energy flows in non-cyclic manner (unidirectional) from sun 4o the decomposers via producers and macroconsumcrs (herbivores and carnivores), whereas the minerals keep on moving in a cyclic manner.
Productivity of Ecosystem The productivity of an ecosystem refers to the rate of production, i.e., the amount of organic matter accumulated in any unit time. It is of following types
3. Net productivity. It is the rate of storage of organic matter not used by the heterotrophs or consumers, i.e., equivalent to net primary production minus consumption by the heterotrophs during the unit period as a season or year, etc.
Food Chains in Ecosystems
In an ecosystem one can observe the transfer or flow of energy from one trophic level to other in succession. A trophic level can be defined as the number of links by which it is separated from the producer, or as the which position of the organism in the food chain. The patterns of eating and being , eaten forms a linear chain called food chain which can always be traced back to the producers. Thus, primary producers trap radiant energy of sun and transfer that to chemical or potential energy of organic compounds such as carbohydrates, proteins and fats. When a herbivore animal eats a plant (or when bacteria decompose it) and these organic compounds are oxidized, the energy liberated is just equal to the amount of energy used in
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// ENGINEERING
2. Secondary productivity. It is the rate ofencrgy storage at consumer's levels herbivores,carnivores and decomposers. Consumers tend to utilise already produced food materials in their respiration and also convert the food matter to different tissues by an overall process. So, secondary productivity is not divided into 'gross' and 'net' amounts. Due to this fact some ecologists such as Odum (1971), prefer to use the term assimilation rather than production at this level - the consumers level. Secondary productivity, in fact, remains mobile (i.e., keeps on moving from one organism to another) and does not live in situ like the primary productivity.
AND
Primary production is measured by following methods—harvest method, oxygen measurement method (or light or dark method), oxygen diurnal curve method, carbon dioxide measurement method (enclosure method), the aerodynamic method, the pH method, radioisotope method, chlorophyll estimation method (see Dash, 1993).
SCIENCE
(ii) Net primary productivity. It is the rale of storage of organic matter in plant tissues in excess of the respiratory utilization by plants during the measurement period.
ENVIRONMENTAL
(i) Gross primary productivity. It refers to the total rate of photosynthesis including the organic matter used up in respiration during the measurement period. GPP depends on the chlorophyll content. The rate of primary productivity are estimated in terms of either chlorophyll content as chl/g dry weight/unit area or photosynthctic number, i.e., amount of CO, fixed/g chl/hour.
D.PARTHIBAN
1. Primary productivity. It is defined as the rate at which radiant energy is stored by photosynthctic and chemosynthetic activity of producers. Primary productivity is of following types:
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synthesizing the substances (first law of thermodynamics), but some of the energy is heat and not useful energy (second law of thermodynamics). If this animal, in rum, is eaten by another one, along with transfer of energy from a herbivore to carnivore a further decrease in useful energy occurs as the second animal (carnivore) oxidizes the organic substances of the first (herbivore or omnivore) to liberate energy to synthesize its own cellular constituents. Such transfer of energy from organism to organism sustains the ecosystem and when energy is transferred from individual to individual in a particular community, as in a pond or a lake or a river, we come across the food chains.
ENVIRONMENTAL
SCIENCE
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ENGINEERING
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D.PARTHIBAN
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1. Grazing food chain. | |
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This type of food chain starts from the living green plants, goes to grazing herbivores and on to the carnivores. Ecosystems with such type of food chain are directly dependent on an influx of solar radiation. Thus, this type of food chain depends on autotrophic energy capture and the movement of this energy to herbivores. Most of the ecosystems in nature follow this type of food chain. These chains are very significant from energy standpoint. The phytoplankton -> zooplanktons -» fish sequence or the grasses -> rabbit -> fox sequence arc the examples of grazing food chain.
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ENVIRONMENTAL
In nature, basically two types of food chains arc recognized—grazing food chain and detritus food chain.
SCIENCE
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ENGINEERING
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D.PARTHIBAN
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Further the producer -> herbivore -> carnivore chain is a predator chain. Parasitic chains also exist wherein smaller organisms consume larger ones without outright killing as the case of the predators.
2. Detritus food chain.
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Significance of food chain. The food chain studies/help under stand the feeding relationships and the interaction between organisms in an ecosystem. They also help us to appreciate the energy flow mechanism and matter circulation in eco- system, and understand the movement of toxic substances in the eco-system and the problem of biological magnification
Food web
Ecological Pyramids
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In the successive steps of grazing food chain-photosynthetic autotroph, herbivorous heterotroph, carnivores heterotroph, decay bacteria-the number and mass of the organisms in each step is limited by the amount of energy available. Since some energy is lost as heat, in each transformation the steps become progressively smaller near the top. This relationship is sometimes called "ecological pyramid". The ecological pyramids represent the trophic structure and also trophic function of the ecosystem. In many ecological pyramids, the producer form the base and the successive trophic levels make up the apex.
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In nature simple food chains occur rarely The same organism may operate in the ecosystem at more than one trophic level i.e it may derive its food from more than one source. Even the same organism may be eaten by several organisms of a higher trophic level or an organism may feed upon several different organisms of a lower trophic level. usually the kind of food changes with the age of the organism and the food availability. Thus in a given ecosystem various food chains are linked together and interested each other to form a complex network called food Web.
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The organic wastes, exudates and dead matter derived from the grazing food chain are generally termed detritus. The energy contained in this detritus in not lost to the ecosystem as a whole; rather it serves as the source of energy for a group of organisms (dctritivorcs that are separate from the grazing food chain, and generally termed as the detritus food chain. Detritus food chain represents an exceedingly important component in the energy (low of an ecosystem. Indeed in some ecosystems, considerably more energy flows through the detritus food chain than through the grazing food chain. In the detritus food chain the energy flow remains as a continuous passage rather than as a stepwise flow between discrete entities. The organisms of the detritus food chain are many and include algae, bacteria, slime molds, actinomycetes, fungi. Protozoa, insects mites. Crustacea, centipedes, molluscs, rotifers, annelid worms, nematodes and some vertebrates. .
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Thus.communiticsof terrestrial ecosystems and shallow water ecosystems contain gradually sloping ecological pyramids because these producers remain large and characterized by an accumulation of organic matter. This trend, however, does not hold for all ecosystems. In such aquatic ecosystems as lakes and open sea, primary production is concentrated in the microscopic algae. These algae have a short-cycle, multiply rapidly, accumulate little organic matter and are heavily exploited by herbivorous zooplankton. At any one point in time the standing crop is low. As a result, the pyramid of biomass for these aquatic ecosystems is inverted: the base is much smaller than the structure it supports. Types of Ecological Pyramids
2. Pyramid of biomass. The biomass of the members of the food chain present at any one time forms the pyramid of the biomass. Pyramid of biomass indicates decrease of biomass in each trophical level from base to apex. For example, the total biomass of the producers ingested by herbivores is more than the total biomass of the herbivores in an ecosystem. Likewise, the total biomass of the primary carnivores (or secondary consumer) will be less man the herbivores and so on.
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1. Pyramid of number. It depicts the number of individual organisms at different trophic levels of food chain. This pyramid was advanced by Charles Elton (1927), who pointed out the great difference in the number of the organisms involved in each step of the food chain. The animals at the lower end (base of pyramid) of the chain are the most abundant. Successive links of carnivores decrease rapidly in number until there are very few carnivores at the top. The pyramid of number ignores the biomass of organisms and it also docs not indicate the energy transferred or the use of energy by the groups in vol ved. The lake ecosystem provides a typical example for pyramid of number.
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The ecological pyramids may be of following three kinds :
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3. Pyramid of energy. When production is considered in terms of energy, the pyramid indicates not only the amount of energy flow at each level, but more important, the actual role the various organisms play in the transfer of energy. The base upon which the pyramid of energy is constructed is the quantity of organisms produced per unit lime, or in other words, the rate at which food material passes through the food chain. Some organisms may have a small biomass, but the total energy they jssimilate and pass on, may be considerably greater than that of organisms with a much larger biomass. Energy pyramids are always slopping because less energy is transferred from each level than was paid into it. In cases such as in open water communities the producers have less bulk than consumers but the energy they store and pass on must be greater than that of the next level. Otherwise the biomass that producers support could not be greater than that of the producers themselves. This high energy flow is maintained by a rapid turn over of individual plankton, rather than an increase of total mass.
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Classification of Ecosystems / Ecology
Ecosystems are broadly classified as : Terrestrial Ecosystems – which encompass the activities that take place on land, and Aquatic ecosystems - the system that exists in water bodies These ecosystems can be further subdivided as: Terrestrial ecosystem - Forest ecosystem, Mountain ecosystem Desert ecosystem Grassland ecosystem Urban ecosystem Aquatic ecosystem Marine ecosystem Fresh water ecosystem Estuarine ecosystem
An ecosystem which is fully designed and controlled by man is called ‘Engineered ecosystem’. A paddy field or a fish pond can be quoted as an example for this ecosystem
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Engineered ecosystem:
Tropical rain forests
They are found near the equator. These forests have a warm annual mean temperature. These forests have high humidity and heavy rainfall almost daily. These forests consists of broadleaf ever green plants’ These trees have larger surface on their leaves that allows them to collect more sunlight and do photosynthesis extensively. Tropical rain forests have wide varieties of species.
Temperate Deciduous forests: refer book Boreal/Conifer forests: refer book
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Tropical rain forests Temperate deciduous forests Boreal/coniferous forests
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There are three important types of forests are
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Undisturbed areas with moderate to high average annual rain precipitation tend to be covered with forest, which contains various species of trees and smaller forms of vegetation.
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FOREST ECOSYSTEM
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DESERT ECOSYSTEM
Deserts are dry places with unpredictable and infrequent precipitation. A desert is an area where evaporation exceeds precipitation.
Daily and seasonal temperature of the desert will vary since desert has very little moisture to absorb and store sun radiation.
Deserts with less than 2.5 cm of precipitation supports almost zero vegetation. Deserts with 2.5 to 5.0 cm precipitation have thin (scanty) vegetation(less than 10% of the ground is covered).
Seasonal leaf production, water-storage tissues and thick epidermal layer help reduce water loss. A combination of low rainfall and different average temperatures creates tropical, temperate and cold deserts.
Precipitation is too low
It consists of drought resistant shrubs, cacti and other succulents* and few animals
Small shrubs
Mojave in south California
Gobi desert in China
*They are the plants survive in dry climates by having no leaves / wax coated leaves and storing water. Many desert animals avoid the drying sun by feeding at night and acquire water from the seeds and green vegetation.
Warm, dry high pressure atmospheric conditions create broad bands of deserts around the world at 300 north and south latitude.
This band includes deserts in the southwest America, north and south Africa, China and Australia. GRASSLAND ECOSYSTEM
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There is more precipitation than tropical deserts
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Winters are too cold, summers are too hot
Grasslands are regions with enough average annual rain precipitation to allow grass to grow extensively. But drought and fire does not allow trees to grow taller. Grasslands are rich biological communities of grasses, seasonal flowering plants and open savannas*. Great Plains of central North America, Russian steppes, African veldt and South American pampas are some of the important grasslands in the world. There are three types of grasslands
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Ex: Sahara in Africa
Day time temperature are high in summer & low in winter
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These driest places on the earth have few plants along with wind blown sands and rocks
COLD DESERTS
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There is very little rainfall during 1 or 2 months of a year.
TEMPERATE DESERTS
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TROPICAL DESERTS Temperatures are high year around
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A. Tropical grasslands B. Temperate grasslands C. Polar grasslands
*grassland with scattered trees Grasslands are an important part of the earth’s many ecological communities, originally covering as much as 25% of the earth’s surface. They have provided expansive grazing land for both wild and domesticated animals, and offered flat areas that have been ploughed to grow crops. Grasslands occur in areas with hot summer temperatures and low precipitation. Areas with less rainfall are deserts and areas with more rainfall tend to be forested. There are two broad types of grasslands in the world: Tropical Savannah and Temperate Grassland. --------------------------------------TROPICAL SAVANNA-----------------------------------
Tropical Savannah occurs in Africa, Australia, South America and Indonesia. Rainfall of 50 to 130 centimetres a year is concentrated in six to eight months with drought the rest of the year. Soils are usually very thin, supporting only grasses and forbs (flowering plants), with only scattered trees and shrubs. Differences in climate and soils create many variations in the plant communities and animal species throughout the Savannah. In many areas, the grasslands have been burned to maintain a healthy grass crop for grazing animals. In some areas the Savannah has been expanded by cutting the forest and burning the area each year to prevent the return of trees.
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Seasonal cycles of temperature and precipitation contributes to abundant vegetative growth that enriches and protects the soil of the grasslands. There is enough water to support small crops to do photosynthesis Grasslands have few trees because inadequate rainfall, large daily and seasonal temperature ranges and frequently grass fires kill woody seedlings. Major impacts on grasslands are: Conversion of grasslands into cropland Overgrazing of grasslands by livestock Exploitation of polar grassland by oil, water and air pollution
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Tropical grasslands They has warm temperature year around with two prolonged dry seasons. They are the shelter for animals like zebras, giraffes, black rhino, and African elephant. Savanna grassland in Africa is good example for tropical grassland. Temperate grasslands Winters are too cold, summers are hot and dry, annual precipitation is less and falls unevenly through the year. Drought, fire and overgrazing inhibits the growth of trees and bushes. The soil in temperate grassland is fertile since grass die and decomposes to for organic manure. Prairies in Canada, Pampas in South America and Veldt in Africa are examples for temperate grasslands. Polar grasslands It is also known as arctic tundra. They occur in arctic polar ice caps. The land is covered with ice and show. Winter is very dark, long and cold.
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-----------------------------------------TEMPERATE GRASSLANDS---------------------------------------Temperate grasslands have less rainfall (25 to 90 centimetres) than tropical grasslands and a much greater range of temperatures from winter to summer than Savannah. There are two broad types of grasslands in temperate latitudes: Prairie and Steppe.
PRAIRIE GRASSLANDS Prairie grasslands are found across the globe. They have a variety of names in other parts of the world: pampas in South America, veldt in South Africa and puszta in Hungary. These areas have deep, rich soils and are dominated by tall grasses; trees and shrubs are restricted to river valleys, wetlands and other areas with more moisture. Over the years the native grass species on the extensive areas of level ground have been ploughed and fields seeded. Many of these grasslands have been lost to cereal crops.
Steppe grasslands receive only 25 to 50 centimetres of rainfall each year and the grasses are much shorter than those on prairie grasslands. They are also not as widespread, occurring only in Central and Eastern Europe, Northern Eurasia and Western North America.
Herbivores eat only plants, such as the elk that graze the grasslands of the Columbia valley, or an insect nibbling on the leaf of a sticky geranium.
Omnivores eat both plants and animals, such as the black bear. Carnivores eat only animals, such as the red-tailed hawk or western rattlesnake. Decomposers include the insects, fungi, algae and bacteria both on the ground and in the soil that help to break down the organic layer to provide nutrients for growing plants. There are many millions of these organisms in each square metre of grassland.
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Consumers are organisms that do not have the ability to capture the energy produced by the sun, but consume plant and/or animal material to gain their energy for growth and activity. Consumers are further divided into three types based on their ability to digest plant and animal material:
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Producers are able to capture the sun’s energy through photosynthesis and absorb nutrients from the soil, storing them for future use by themselves and by other organisms. Grasses, shrubs, trees, mosses, lichens, and cyanobacteria are some of the many producers found in a grassland ecosystem. When these plants die they provide energy for a host of insects, fungi and bacteria that live in and on the soil and feed on plant debris. Grasses are an important source of food for large grazing animals such as California Bighorn Sheep, Mule Deer and Elk, and for much smaller animals such as marmots, Pocket Gophers and mice.
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The biotic components of a grassland ecosystem are the living organisms that exist in the system. These organisms can be classified as producers, consumers or decomposers.
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STEPPE GRASSLANDS
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WATER ECOSYSTEMS Fresh water ecosystems: Marine ecosystems: Freshwater Ecosystems Wetlands:
once considered useless, disease disease-ridden places (e.g., malaria and yellow fever)
among the most productive ecosystems in the world, comparable to rain forests and coral reefs. They also are a source of substantial biodiversity in supporting numero numerous us species from all of the major groups of organisms – from microbes to mammals.
Limnetic zone - the open water area where light does not generally penetrate all the way to the bottom Euphotic zone - the layer from the surface down to the depth where light levels become too low for photosynthesis Benthic zone - the bottom sediment
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Littoral zone - light penetrates to the bottom, allowing aquatic plants to grow
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divided into zones based on photosynthetic activity & proximity to bottom:
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Lakes
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provide many benefits to society: o fish and wildlife habitats o natural water quality improvement o flood storage o shoreline erosion protection o opportunities for recreation and aesthetic appreciation
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Major threats to our lakes: o An overabundance of nutrients. This leads to algal blooms and excessive plant growth which ultimately deplete oxygen supplies for fish and some other aquatic life. o An overabundance of sediment. This "runoff" soil can fill lake lakes s and destroy habitat for plants and animals, as well as clog fish gills and smother fish eggs. o Metals and other organic chemicals such as polychlorinated biphenyls (PCBs), contaminating fish and shellfish.
Sources of lake pollution: o Agricultural manage management ment practices can lead to pollutants like nitrogen, phosphorous, sediment, & pesticides and entering a lake. o Runoff from pavement and lawns in urban areas picks up oil, metals, bacteria (including E. coli), ), nutrients, and transports them through the stor storm m sewer system. o Septic systems also contribute to lake pollution when they leak into the shallow groundwater. This can also increase the load of nutrients, bacteria (including E. coli) and other organic wastes.
70% of the earth’s surface Zones:
The ocean bottom is the benthic zone and the water itself (or the water column) is the pelagic zone. The neritic zone is that part of the pelagic zone that extends from the high tide line to an ocean bottom less than 600 feet deep. Water deeper than han 600 feet is called the oceanic zone,, which itself is divided on the basis of water depth into the epipelagic, mesopelagic, and bathypelagic zones. These zones roughly correspond to the three other zones divided on the basis of the amount of sunlight they th receive. In the sunlit zone,, enough light penetrates to support photosynthesis. Below that lies the twilight zone, zone where very small amounts of light penetrate. Ninety percent of the space in the ocean lies in the midnight zone, which is entirely devoid of light.
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Oceans
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Two important communities found in the neritic province are: Tidal marshes & estuaries o a partially enclosed body of water formed where freshwater from rivers and streams flows into the ocean, mixing with the salty sea watere o among the most productive ecosystems on earth, creating more organic matter each year than comparably-sized areas of forest, grassland, or agricultural land o provide habitat for more than 75% of America's commercial fish catch, and for 80-90% of the recreational fish catch
Coral reefs o cover less than 1% of the planet's surface o the world's most biologically diverse marine ecosystems o Reef ecosystems are now being rapidly degraded & destroyed worldwide due to: increased sediments in the water trampling by tourists and divers ship groundings, pollution, overfishing fishing with poisons and explosives that destroy coral habitat
Whaling Incidental take or bycatch o the unintended catch of animals associated with commercial fishing operations, the vast majority of which is discarded back into the ocean already dead or dying. o Bycatch is pervasive the world's fisheries. It includes undersized or juvenile fish of targeted species as well as non-target species of fish, turtles, marine mammals, birds, and other wildlife.
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Environmental problems facing our oceans:
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ESTUARIES
They are bays or partially enclosed bodies of brackish water* that form where river enter into ocean. Estuaries contain rich sediments carried down river, forming mudflats that act as home for many aquatic lives. The combination of certain physical factors makes them very protective and of high species diversity. Deltas, broad, shallow deposits of river borne sand and mud, can be part of the larger estuary zone; a steady flow of nutrients makes deltas biologically rich. *Salty water
Biodiversity and its conservation
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Wetlands are ecosystem in which the land surface is covered with standing water for at least part of the year. Wetland vegetation is adapted for growth under saturated condition. There are 3 types of wetlands: 1. Swamps: they are wetlands with trees 2. Marshes: they are wetlands without trees 3. Bogs & fens: they are waterlogged areas saturated by ground/rainwater Water in marshes and swamps is shallow enough so that sun light cab easily penetrates through the water, hence photosynthesis is high. Biomass production and species diversity are high compared to surrounding uplands. Activities like breeding, nesting and migration of water birds and shore birds are high. Wetlands are acting as natural water purifying system by removing slit and absorbing toxins. Most popular wetlands are in Canadian and Russian arctic tundra.
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WETLANDS
Biodiversity is the variety of life on earth It includes all life forms-from the unicellular fungi, protozoa and bacteria to complex multi-cellular organisms such as plants, birds, fishes and animals. Biodiversity is the variety of flora and fauna on this planet earth. According to the World Resources Institute-"Biodiversity is the variety of the world's organisms, including their genetic diversity and the assemblage they form.” The concept reflects the inter-relatedness of genes, species and ecosystems. Because genes are the components of species, and species are the components of ecosystems. From the driest deserts to the dense tropical rainforests and from the high snow-clad mountain peaks to the deepest of ocean trenches, life occurs in a marvelous spectrum of forms, size,
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ENVIRONMENTAL
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Introduction:
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colour and shape, each with unique ecological inter-relationships. Diversity may be defined as the number of species present in a community, a measure termed as 'species richness'.
GENETIC DIVERSITY
Rice grown in Asia is protected from the four main rice diseases by genes brought in from a wild species from India. The sugarcane industry in the US was saved from collapse by disease – resistance genes brought in from wild Asiatic species. A tomato discovered in Andes has been used to increase the sugar content of cultivated varieties, increasing their commercial value.
SPECIES DIVERSITY A species generally consists of all the individual organisms of a natural population which are able to interbreed, generally sharing similar appearance, characteristics and genetics. A species is one of the basic units of biodiversity.
Measurement of species:
Species richness is the simplest measure of biodiversity and is simply a count of the number of different species in a given area. Species evenness is a diversity index, a measure of biodiversity which quantifies how equal the populations are numerically. So if there are 40 foxes, and 1000 dogs, the population is not very even. But if there are 40 foxes and 42 dogs, the population is quite even. This is the variability found within the population of a species or between different species of a community. It represents broadly the species richness and their abundance in a community.
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Value of Genes
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It refers to the total genetic information contained in the genes of individuals of plants, animals and microorganisms. The genes found in organisms can form enormous number of combinations each of which gives rise to some variability. Genes are the basic units of hereditary information transmitted from one generation to other. When the genes within the same species show different versions due to new combinations, it is called genetic variability. For example, all rice varieties belong to the species Oryza sativa, but there are thousands of varieties of rice which show variations at the genetic level and differ in their color, size, shape, aroma and nutrient content of the grain. This is the genetic diversity of rice. New genetic variation arises due to in individuals, by gene and chromosome mutation.
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ECOSYSTEM DIVERSITY
environment, how it "fits into" an ecosystem.
A niche may apply to species, populations or even individuals. The concept of the ecological niche is an important one; it helps us to understand how
organisms in an ecosystem interact with each other. The ecological niche of an organism depends not only on where it lives but also on what it does. By analogy, it may be said that the habitat is the organism's "address", and the niche is its “profession", biologically speaking.
What do oak trees do?
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habitat, and place in the food chain.
A niche is the sum total of an organism’s use of biotic and abiotic resources in its
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The description of a niche may include descriptions of the organism's life history,
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Ecological Niche
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This is the diversity of ecological variations in ecological niches(places), trophic structure, food-webs, nutrient cycling etc. The ecosystems also show variations with respect to physical parameters like moisture, temperature, altitude, precipitation etc. The ecosystem diversity is of great value that must be kept intact. This diversity has developed over millions of years of evolution. If we destroy this diversity, it would disrupt the ecological balance. We cannot even replace the diversity of one ecosystem by that of another. Coniferous trees of boreal forests cannot take up the function of the trees' of tropical deciduous forest lands and vice versa.
absorb sunlight by photosynthesis; absorb water and mineral salts from the soil; provide shelter for many animals and other plants; act as a support for creeping plants; serve as a source of food for animals; Cover the ground with their dead leaves in the autumn.
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ENVIRONMENTAL
Know the oak trees "profession" or its ecological niche.
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These six things are the "profession" or ecological niche of the oak tree;If the oak trees were cut down or destroyed by fire or storms they would no longer be doing their job and this would have a disastrous effect on all the other organisms living in the same habitat.
Measurement of biodiversity There are three other indices which are used by ecologists: Alpha diversity It refers to diversity within a particular area, community or ecosystem, and is measured by counting the number of distinct groups of animals (taxa) within the ecosystem.Ex. Families, species
It is species diversity between ecosystems; this involves comparing the number of distinct groups of animals (taxa) that are unique to each of the ecosystems. It gives a quantitative measure of diversity of communities that experience changing environments. Gamma diversity
Some fundamentals in biogeography are
Evolution (change in genetic composition of a population) Extinction (disappearance of a species) Dispersal (movement of populations away from their point of origin, related to migration) Range and distribution Endemic areas
Biogeography is of two types
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Biogeography: It is the science which deals with patterns of species distribution and the processes that result in such patterns.
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Bio-Geographical Classification of India
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It is a measure of the overall diversity for different ecosystems within a region. It refers to the total biodiversity over a large area or region.
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Beta diversity
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India has different types of climate and topography in different parts of the country and these variations have induced enormous variability in flora and fauna. India has a rich heritage of biological diversity Bio-geographic zones: Major zones representing distinctive units of similar ecology, biome representation, community and species. e.g. Himalaya, Gangetic plain. Biotic provinces: Next level of detail within the zones. e.g. Northwestern Himalaya, Western Himalaya. Biomes: Major ecosystem groupings found within each province and region. e.g. Alpine, subalpine. In order to gain insight about the distribution and environmental interactions of flora and fauna of our country, it has been classified into ten bio-geographic zones. Each of these zones has its own characteristic climate, soil, topography and biodiversity. Within India the classification recognizes 10 Zones, divided into 26 Provinces
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Trans-Himalaya with 2 provinces The Himalaya with 4 provinces The Indian Desert with 2 provinces The Semi-Arid Zone with 2 provinces The Western Ghats with 2 provinces The Deccan Peninsula with 5 provinces The Gangetic Plain with 2 provinces The Coasts with 3 provinces North East India with 2 provinces The Islands with 2 provinces
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The zones are:
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Bio-geographic Zones 1. Trans-Himalaya:
Biotic Province: Ladakh (J&K) and Lahaul - Spiti (Himachal)[1] Biome: Tundra valley, lakes and marshes. Wildlife: Chiru, Black-necked Crane, Himalayan pit viper.
2. Himalaya:
Biotic Province: Northwestern Himalaya (2a), Western Himalaya (2b), Central Himalaya (2c), Eastern Himalaya (2d). Biome: All alpine, temperate conifer, temperate broadleaf, subtropical Wildlife: Ibex, red panda, Monal Pheasant.
5. Western Ghats:
Biotic Province: Western Ghats[5] Biome: Evergreen, moist deciduous, wetlands, Montane forests, grasslands. Wildlife: Lion-tailed macaque, Malabar civet, hornbill, draco.
6. Deccan Peninsula:
Biotic Province: Southern Plateau (6a), Central Plateau (6b), Eastern Plateau (6c), ChhotaNagpur (6d), Central Highlands (6e). Biome: Dry deciduous, thorn forests, wetlands, subtropical, moist deciduous. Wildlife: Swamp deer, Jerdon’s Courser, mugger.
7. Gangetic Plains:
Biotic Province: Lower and upper Gangetic plains (7). Biome: Alluvial plain, wetlands, rivers. Wildlife: Rhino, otter, Gangetic dolphin, terrapin.
8. Northeast India:
Biotic Province: Assam Plains (8a), Shillong Plateau (8b).
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Biotic Province: Punjab and Gujarat-Rajwara[4] Biome: Scrublands, Bhabar forests, wetlands, dry deciduous, hill and thorn forests. Wildlife: Tiger, Asiatic lion, Great Indian Bustard, gharial.
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4. Semi-arid:
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Biotic Province: Kutchh (3a), Thar (3b). Biome: Saltflats,scrublands, desert grasslands. Wildlife: Wild ass, blackbuck, flamingo,desert monitor.
ENVIRONMENTAL
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3. Indian Desert:
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Biome: All plain grasslands, woodlands, Bhabar terai, evergreen moist deciduous, wetlands andrivers, subtropical temperate. Wildlife: Pygmy hog ,serow, Yellow-backed Sunbird.
9. Islands:
Biotic Province: Andaman and Nicobar (9a), Lakshadweep (9b). Biome: Evergreen, moist deciduous, subtropical temperate wetlands, coastal habitat. Wildlife: Dolphin, Narcondam Hornbill, olive ridley turtle.
10. Coasts:
These are direct use values where the biodiversity product can be harvested and consumed directly e.g. fuel, food, drugs, fibre etc.
Drugs and medicines:
About 75% of the world's population Depends upon plants or plant extracts for medicines. The wonder drug Penicillin used as an antibiotic is derived from a fungus called "Penicillium. we get Tetracyclin from a bacterium. Quinine, the cure for malaria is obtained from the bark of Cinchona tree, Digitalin is obtained from foxglove (Digitalis) which is an effective cure for heart disease. Vinblastin and vincristine, two anticancer drugs, have been obtained from Periwinkle (Catharanthus) plant, which possesses anticancer alkaloids.
Table 1 . Natural medicinal products
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Consumptive value:
SCIENCE
Value of Bio-Diversity
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Biotic Province: West Coast (10a), East Coast (10b). Biome: Mangrove, brackish lakes and lagoons, mudflats, sandy or rocky littoral. Wildlife: dugong, Brahminy Kite, sand skink.
ENVIRONMENTAL
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S.NO
PRODUCT
SOURCE
1.
Aspirin
Willow bark
2.
Allantoin
Blowfly larva
3-
Bacitracin
Bacterium
Antibiotic
4.
Bee venom
Bee
Arthritis relief
5.
Cytarabine
Sponge
Leukemia cure
6.
Cortisone
USE Anti-inflammatory Wound healer
Anti-inflammatory
7.
Digitalis
Foxglove plant
Heart stimulant
8.
Diosgenin
Mexican yam
9.
Erythromyci
Bacterium
Antibiotic
10.
Morphine
Poppy plant
Analgesic
11.
Penicillin
Fungus
Antibiotic
12.
Quinine
Chincona bark
Malaria treatment
13.
Reserpine
Rauwolfia
Hypertension drug
14.
Tetracycline
Bacterium
Antibiotic
15.
Vinblastine
Rosy periwinkle
Anti-cancer drug plant
16.
Vincristine
Rosy periwinkle
Anti-cancer drug plant
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Fuel: Our forests have been used since ages for fuel wood. The fossil fuels coal, petroleum and natural gas are also products of fossilized biodiversity. Productive Values: These are the commercially usable values where the product is marketed and sold. These may include the animal products like tusks of elephants, musk from musk deer, silk from silk-worm, wool from sheep, fir of many animals etc, all of which are traded in the market. Genetic Value: Biological diversity is a valuable genetic resource. Most of the hybrid varieties of crops under cultivation have been developed by incorporating useful genes from different species of plants to produce better quality of the product with longer self-life or having better resistance to pests. The genes from the Kans grass (Saccharum Spontaneum) grown in Indonesia helped in imparting resistance to red rot disease of sugarcane.
ENVIRONMENTAL
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Birth-control drug
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Mexican yam
85
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A wild variety of rice from UP. Saved millions of hectares of paddy crop from Grossy-Stunt virus.
Social Values/Ethical values: These are the values associated with the social life, customs, religion and aspects of the people. Many of the plants are considered holy and sacred in our country like Tulsi (holy basil), Peepal, Mango, Lotus, Neem etc. The leaves, fruits or flowers of these plants are used in worship or the plant itself is worshipped. The tribal people are very closely linked with the wild life in the forests.
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Aesthetic value: Great aesthetic value is attached to biodiversity. We will not like to visit vast barren lands with no signs of visible life. People from far and wide spend a lot of time and money to visit wilderness areas where they can enjoy the aesthetic value of biodiversity and this type of tourism is now known as ecotourism.
Ecological value:
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prevention of soil erosion, prevention of floods, maintenance of soil fertility, nutrients cycles, fixation of nitrogen, hydrological cycle, acts as carbon sinks, pollutant absorption Reduction of the threat of global warming etc.
Levels of Bio-Diversity BIODIVERSITY AT GLOBAL LEVEL: ö
ö ö ö
Cellular life has existed on Earth for probably more than 3,500 million years, but for more than half this time consisted only of prokaryotes (i.e. unicellular organisms such as bacteria and blue-green algae).Multi-cellular animals (metazoans) first appeared some 600 million years ago. The present geological era is perhaps the richest in biological diversity. About 2.1 million species have been identified till date, while many more species are believed to exist, The total number of species that might exist on Earth range between 9.0 – 52 million Invertebrate animals and plants make-up most of the species. About 70% of all known species are invertebrates (animals without backbones such as insects, sponges, worms, etc.); while, about 15% are plants.
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It refers to the services provided by ecosystems such as
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Tropical deforestation alone is reducing the biodiversity by half a percent every year. Many of these species are more vulnerable to extinction when their natural home is destroyed. About 50 to 80% of global biodiversity lies in these rainforests. More than one-fourth of the world's prescription drugs are extracted from plants growing in tropical forests. Temperate forests have much less biodiversity. Globally, we have roughly 1, 70,000 = flowering plants 30,000 = vertebrates 2, 50,000 = other groups of species
It is estimated that there exists 5-30 million species of living forms on our earth .Of these only 1.5 million are identified. :
300,000
species
Insects
:
8, 00,000
species
Vertebrates
:
40,000
species
Microorganisms
:
3, 60,000
species
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Green Plants and Fungi
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Warmer areas hold more species than the colder areas; Wetter areas hold more species than the drier ones; Areas of varied climate and topography hold more species than the areas of uniform climate and topography; Areas at lower altitude (elevation) hold more species than the high altitude areas; Less seasonal areas hold more species than the highly seasonal areas.
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The species richness depends on the following environmental conditions:
Every country is characterized by its own biodiversity depending mainly on its climate. India has a rich biological diversity of flora and fauna. Overall six percent of the global species are found in India. It is estimated that India ranks 10th among the plant rich countries of the world, India ranks 11th in terms of number of endemic species of higher vertebrates. India ranks 6th place among the centers of diversity and origin of agricultural crops. The total number of living species identified in our country is 150,000. Indian is also one of the 12 mega-biodiversity countries in the world. Out of a total of 25 biodiversity hot-spots in the world, India possesses 2, one in the northeast region and second one in the western ghats.
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ENVIRONMENTAL
Indian Biodiversity:
SCIENCE
BIOLOGICAL DIVERSITY AT NATIONAL LEVEL :
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India as a mega-diversity nation The country has a rich heritage of biodiversity, a wide spectrum of habitats from rainforests to alpine vegetation, and from temperate forests to coastal wetlands.
tropical
Endemism: Species which are restricted only to a particular area are known as endemic. About 62% of amphibians and 50% of lizards are endemic to India. Western ghats are the site of maximum endemism. India has 26 recognized endemic centers. Biosphere reserves : which protect larger areas of natural habitat ,it includes National Parks, preserves, along buffer zones that are open to some economic uses. The World has 482 biosphere reserves in 102 countries. India has World heritage sites Biosphere reserves Wetlands Botanical gardens National parks Sanctuaries
5 12 6 33 89 504
The Ministry of Forests and Environment (MOEF) reports that India has at present 89,317 species of fauna and 45,364 species of flora representing about 7.31% of the world fauna and 10.88% the world flora described so far. Center of origin: India has been the center of origin for Flowering plants Cultivated crop plants Wild crops
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5000 species 166 species 320 species
Marine diversity:. The number of zooplankton recorded is about 16,000 species. Over 30 species of marine algae and 14 species of sea grass have been reported. There are over 45 species of mangroove plants. Over 342 species of corals have been reported and about 50% of the world's reef building corals are found in India.
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India occupies 2.4% of the total land area of the world, but India contributes 8.22% of the known global biodiversity. India is one of the 12 mega-diversity nations of the world. India is in the 10th position in the world and fourth in the Asia in terms of plant diversity. India ranks 10th in the world in terms of number of mammalian species,; India ranks 11th in the world in terms of endemic species of higher vertebrates In terms of number of species contributed to agriculture and animal husbandry, it ranks 7th in the world. India has two major realms called the Palaearctic and the Indo- Malayan; India has three biomes, namely the tropical humid forests, the tropical dry deciduous forests and the warm desert/semi-deserts. India can be divided into ten biogeographic zones and 26 biotic provinces which represent the major ecosystems of the world. Out of 25 hotspots in the world, India has two 'hotspots'—the Western Ghats and the Eastern Himalayas.
ENVIRONMENTAL
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Almost all the bio-geographical regions of the world are represented here in India.
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2.
Keoladeo Ghana National Park
Rajasthan
3.
Manas Wildlife Sanctuary
Assam
4.
Nanda Devi National Park
Uttar Pradesh
5.
Sundarban National Park
West Bengal
Hot spots of Bio-Diversity:
Hotspots are the main areas of focus for biodiversity conservation. These are the areas that are extremely rich in biodiversity, have high level of endemism, and are under constant threat of species extinctions and habitat destruction.
Myers et al (2000) recognized 25 hot spots ay global level. Out of 25, two are present in India, namely the Eastern Himalayas and Western Ghats.
Nearly 70% of the bird species in this hotspot are endemic. These are the areas of high diversity, endemism and are also threatened by human activities. About 40% of terrestrial plants and 25% of vertebrate species are endemic and found in these hotspots. These identified hotspots of biodiversity are:Caribbean,
California Floristic Province and Mesoamereca in North and Central America ; Tropical Andes, Choco-Darien-Western Ecuador, Atlantic Forest, Brazilian Cerrado and Central Chilein South America ; Caucasus and Mediterranean Basin in Europe and Central Asia; Madgascar and Indian Ocean Islands, Eastern Arc Mountains and Coastal Forests, Guinean Forests of West Africa,Cape Floristic Region and Succulent Karoo in Africa; Mountains of Southwest China, Indo-Burma and Western Ghats of India in Mainland Asia; and Philippines, Sundaland, Wallacea, Southwest Australia, Newzeland, New Calenonia and Polynesia and Micronesia in Asia Pacific region.
It has been estimated that 50,000 endemic plants,which comprise 20% of global plant life, probably occur in only 18 ‘hotsopts’ in the world. Countries which have a relatively large proportion of these biodiversity hotspots are referred to as ‘mega-diversity nations.’
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Assam
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Kaziranga National Park
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LOCATION
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SITE
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S.NO.
89
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Hotspots in India: Eastern Himalayas:
# # # #
All Himalayan forests lie north of the Tropic of Cancer, and some of them are at attitudes of 1780 -3500 m, they can be considered tropical forests. The Eastern Himalayas display an varied topography, a factor that fosters species diversity and endemism. Many deep and semi-isolated valleys are exceptionally rich in endemic plant species, In Sikkim, in an area of 7298 km2 , of the 4250 plant species , 2550 (60%) are endemic. In India’s sector of the area, there are about 5800 plant species,of which roughly 2000(36%) are endemic. In Nepal, there are around 7000 plant species, many of which overlap with those of India, Bhutan, and even Yunnan. OF these speices, atleast 500(8%) are believed to be endemic to Nepal. Bhutan possesses an estimated 5000 species, of which as many as 750 (15%) are considered to be endemic to the Eastern Himalyas.
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Western Ghats:
D.PARTHIBAN
#
The area comprises Nepal,Bhutan, and neighbouring states of northern India, along with some place of the Yunnan province in Southwest china.
Extinction, the elimination of a species, is a normal process in nature. Species however, human impacts on populations and ecosystems have accelerated that rate of extinction, causing hundreds of species, sub-species and varieties to become extinct every year. The causes of extinction are:
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Population Risk: uneven change in population rates (i.e. birth rates and death rates) can cause a species in low abundance to become extinct.. For example—blue whales. As they swim over the vast areas of ocean, and if in one year most whales were unsuccessful in finding a mate then births could be dangerously low.
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Environmental Risk: Environmental risk means variation in the physical or biological environment, including variations in predator, prey, symbiotic or
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ENVIRONMENTAL
Threats to Bio-Diversity
SCIENCE
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Out of India’s 49219 plant species , 1600 endemics(40% of the total number of endemics) are found in an 17000km2 along the sea side of the Western Ghats in Maharasthtra, Karnataka, Tamil Nadu, Kerala Forest track up to 500 in elevation, comprising one – fifth of the entire forest expanse, are mostly evergreen, while those in 500-1500 m range are semi- evergreen. There are two main centres of diversity, the Agasthyamalai Hills and the Silent Valley/New Amambalam Reserve Basin. The forest cover in western ghats has reduced 34 % from 1972- 1989.
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Human Actions: human activities like hunting ; development of agriculture,rise of civilization, rapid deforestation and introduction of industrial chemicals and emissions, pesticides and pollution are also leads to extinction of species.
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Habitat Loss and Degradation: Habitat loss and degradation are the major proximate causes of species extinction, affecting 89% of all threatened birds, 83% of mammals and 91% of all threatened plants assessed globally .The main causes of habitat loss are agricultural activities, harvesting or extraction (including mining, fishing, logging, etc.) and development of human settlements, industry and associated infrastructure.
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Habitat Fragmentation: Habitat fragmention may take place due to the development of roads, towers, canals, fields, industries, etc. in an original large habitat. Habitat fragmentation divides populations into isolated groups.These isolated, small, scattered populations are increasingly vulnurable to inbreeding depression, high infant mortality and susceptible to environmental hardships, and consequently, in the end, possible extinction.
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Diseases: Pathogens, or disease organisms, may cause extinction. Animals [in sanctuaries and reserves] are more prone to infection when they are under stress.
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Poaching: Poaching is another threat to living species. Wildlife is sold for live specimens, folk medicines, furs, hides, skin (or leather) and other products such as ivory, antlers and horns.
MAN - WILDLIFE CONFLICTS We have discussed about the need to preserve and protect our wildlife. However, sometimes we come across conflicting situations when wildlife starts causing immense damage and danger to man and under such conditions it becomes very difficult for the forest department to pacify the affected villagers and gain local support for wild-life conservation. Instances of man animal conflicts keep on coming to lime light from several states in our country. In Sambalpur, Orissa 195 humans were killed in the last 5 years by elephants. In retaliation the villagers killed 98 elephants and badly injured 30 elephants. Several instances of killing of elephants in the border regions of Kote-Chamarajanagar belt in Mysore have been reported recently. The man- elephant conflict in this region has arisen because of the massive damage done by the elephants to the farmer's cotton and sugarcane crops. The agonized villagers electrocute the elephants and sometimes hide explosives in the sugarcane fields, which explode as the elephants intrude into their fields. In fact, more killings are done by locals than by poachers. Recently, in early 2004, a man-eating tiger was reported to kill 16 Nepalese people and one 4- year old child inside the Royal Chitwan National Park, 240 Km South-west of Kathmandu. The Park renowned for its wildlife conservation effort has became a zone of terror for the locals. At times, such conflicting situations have been reported from the border regions of Corbett, Dudhwa,
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Genetic Risk: Change in genetic characteristics in a small population of a species, due to reduced genetic variation, genetic drift or mutation, genetic assimilation[cross-breeding] makes the species more vulnerable to extinction
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SCIENCE
Natural calamities: A natural catastrophe is a sudden change in the environment .It includes fires, storms, floods, earthquakes, volcanic eruptions etc. Such a natural catastrophe may cause the extinction of most forms of life there.
ENVIRONMENTAL
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D.PARTHIBAN
competitor species. In case of species that are sufficiently rare and isolated, such normal environmental variations can lead to their extinction.
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Palamau and Ranthambore National Parks in our country as well. Very recently in June, 2004 two men were killed by leopards in Powai, Mumbai. A total of 14 persons were killed during 19 attacks since January by the leopards from the Sanjay Gandhi National Park, Mumbai which has created a panic among the local residents. nts.
ENVIRONMENTAL
Endangered Species of India
SCIENCE
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Dwindling habitats of tigers, elephants, rhinos and bears due to shrinking forest cover compels them to move outside the forest and attack the field or sometimes even humans. Human encroachment into tthe he forest areas raises a conflict between man and the wildlife, perhaps because it is an issue of survival of both. Usually the ill, weak and injured animals have a tendency to attack man. Also, the female tigress attacks the human if she feels that her ne newborn wborn cubs are in danger. But the biggest problem is that if human human-flesh is tasted once then the tiger does not eat any other animal. At the same time, it is very difficult to trace and cull the man man-eating eating tiger and in the process many innocent tigers are also killed. Earlier, forest departments used to cultivate paddy, sugarcane etc. within the sanctuaries when the favourite staple food of elephants i.e. bamboo leaves were not available. Now due to lack of such practices the animals move out of the forest in search of food. It may be noted that, One adultelephant needs 2 quintals of green fodde fodderr and 150 kg of clean water daily and if it is not available,the animal strays out. Very often the villagers put electric wiring around their ripe crop fields. The elephants get injured, suffer in pain and turn violent. Earlier there used to be wild wild-life life corridors through which the wild animals used to migrate seasonally in groups to other areas. Due to development of human settlements in these corridors, the path of wildlife has been disrupted and the animals attack the settlements. The cash compensation paid by the government in lieu of the damage caused to the farmers crop is not enough. In Mysore, a farmer gets a compensation of Rs. 40074007 per quintal of expected yield while the market price is Rs. 2400/ 2400/- per quintal. The agonized agoni farmer therefore gets revengeful and kills the wild animals.
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Causes of Man- Wild life conflicts:
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In India, nearly 450 plant species have been identified in the categories of endangered, threatened or rare. Existence of about 150 mammals and 150 species of birds is estimated to be threatened while an unknown number of species of insects are endangered. It may not be of direct relevance here to give a complete list of endangered flora and fauna of our country. However, a few species of endangered reptiles, birds, mammals and plants are given below:
D.PARTHIBAN
The International Union of Conservation of Nature and Natural Resources (IUCN) maintains what may be called a 'Red Database' at the World Conservation Monitoring Centre (WCMC) in which information on endangered and vulnerable species of plants and animals is kept. From time to time, this database is translated into popular form and published as 'Red Data Books'. The red data symbolizes the warning arning signal for those species which are endangered and if not protected are likely to become extinct in near future.
ö ö ö ö
Great Indian bustard, Peacock, Pelican, Great Indian Hornbill, Siberian White Crane
Carnivorous: ö ö ö ö ö ö ö ö ö ö
Indian wolf, red fox, Sloth bear, red panda, Mammals tiger, leopard, striped hyena, Indian lion, golden cat, desert cat
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Birds:
SCIENCE
Gharial, green sea turtle, tortoise, python
ENVIRONMENTAL
ö ö ö ö
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Reptiles:
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Primates: ö ö ö ö ö
Hoolock gibbon, lion-tailed macaque, Nilgiri langur, Capped monkey, golden monkey
Plants: ö ö ö ö ö
A large number of species of orchids, Rhododendrons, medicinal plants like Rauvolfia serpentina, the sandal wood tree Santalum, Cycas beddonei
ENVIRONMENTAL
SCIENCE
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The species that are under threat such that they may have to be classified as endangered in the near future if causal factors continue to operate. These include species whose populations have been seriously depleted and whose ultimate security is not assured, as well as those species whose populations are still abundant but are under threat throughout their range.
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Vulnerable Species:
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A species is said to be endangered when its number has been reduced to a critical level or whose habitats, have been drastically reduced and if such a species is not protected and conserved, it is in immediate danger of extinction.
D.PARTHIBAN
Endangered Species:
Rare Species:
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These are species with small total population size in the world. In their distribution, they are usually localized within restricted habitats or geographical area or are thinly scattered over an extensive range. It is necessary to mention here that a speci species es that is rare is not necessarily in danger of becoming extinct; some species, like the whooping crane, are naturally rare. However, rarity does raise concerns about the possibility of extinction. Rare species, thus, are not at present endangered and , vulnerable but are at risks.
Threatened Species:
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D.PARTHIBAN
The term 'threatened' is used in the context of conservation of the species which are in any one of the above three categories. These are species that have declined significantly in total numbers and may be on the verge of extinction in certain localities.
According to the Red data book ANIMALS 10 54 143 99
AND
= = = =
PLANTS
Critically endangered plants Endangered plants Vulnerable plants Near threatened
= = = =
44, 113 87 38
Some of the animal species that have been identified as endangered or threatened mammals are listed below:
Golden monkey Indian wolf Jackal Red fox
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Critically endangered Endangered animals Vulnerable animals Near threatened
ENVIRONMENTAL
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Indian fox Wild dog Himalayan brown beer Red panda Tiger Indian Lion Leopard Desert Cat Jungle Cat Leopard Cat Golden Cat Indian wild ass
Of the 49,219 plant species, 5,150 are endemic (not found elsewhere) and distributed into 141 genera under 47 families corresponding to about 30% of the world's recorded flora, which means 30% of the world's recorded flora are endemic to India . About 15,000 species of flowering plants (angiosperms) are known to occur in India, out of which 4,950 species of flowering plants had a birth in India. Of-all these enedemic plant species, 3,500 are found in the Himalayas and adjoining regions and 1,600 in the Western Ghats alone. Many deep and semi-isolated valleys are exceptionally rich in endemic plant species. Such as, in Sikkim, in an area of 7,298 square kilometer, of the 4,250 plant species, 2,550 (60%) are endemic.
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Out of about 47,000 species of plants in our country 7000 are endemic. Thus, Indian subcontinent has about 62% endemic flora, restricted mainly to Himalayas, Khasi Hills and Western Ghats. Some of the important endemic flora include orchids and species like Sapria himalayana, Uvaria lurida, Nepenthes khasiana, Pedicularis perroter etc. A large number out of a total of 81,000 species of animals in our country is endemic. The Western Ghats are particularly rich in amphibians (frogs, toads etc.) and reptiles (lizards, crocodiles etc.). About 62% amphibians and 50% lizards are endemic to Western Ghats. Different species of monitor lizards (Varanus), reticulated python and Indian Salamander and Viviparous toad Nectophhryne are some important endemic species of our country.
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India has two biodiversity hot spots and thus possesses a large number of endemic species.
SCIENCE
The endemism of Indian biodiversity is quite high. About 33% of the country's flora are endemic to the country and are concentrated mainly in the North-East, Western Ghats, North-West Himalaya and the Andaman and Nicobar Islands.
ENVIRONMENTAL
Endemics are species that are found in a single locality/area and nowhere else in the world. They, thus, have a value in their uniqueness. Areas of endemism containing several endemic species, genera or even families have generally been isolated for a long time, thus enabling the original species to evolve into new genetic entities better adopted to local area. Isolated mountain tops, valleys and large oceanic Islands are usually areas of endemism.
D.PARTHIBAN
Endemic Species of India:
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Conservation of resources of these areas is very difficult as each area will pose its other peculiar problems. 1. Toothbrush orchid endemic to Sikkim 2. Nepenthes khasiana (Pitcher plant) Endangered and endemic 3. An endangered endemic orchid of Eastern Himalayas 4. Piatycerium, rare and endemic to Manipur
(i) to maintain essential ecological processes and life-supporting systems ; (ii) to preserve the diversity of species or the range of genetic material found in the organisms on the planet; and (iii) to ensure sustainable utilization of species and ecosystems which support millions of rural communities as well as the major industries all over the world. The wildlife conservation efforts are mostly centred on protecting plant and animal life in protected habitats, such as—botanical gardens, zoos, sanctuaries, national parks, biosphere reserves, etc.
There are two approaches of biodiversity conservation: (a) In situ conservation (within habitat): This is achieved by protection of wild flora and fauna in nature itself, e.g. Biosphere Reserves,National Parks, Sanctuaries, Reserve Forests etc.
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Conservation of our natural resources has the following three specific objectives:
SCIENCE
Definition : The act or process of conserving. The protection, preservation, management, or restoration of wildlife and of natural resources such as forests, soil, and water. Conservation is defined as 'the management of human use of the biosphere so that it may yield the greatest sustainable benefit to present generation while maintaining its potential to meet the needs and aspirations of future generations'.
ENVIRONMENTAL
The enormous value of biodiversity due to their genetic, commercial, medical, aesthetic, ecological and optional importance emphasizes the need to conserve biodiversity. Many factors are threatening the world’s biological heritage. The challenge is for nations, government agencies, organizations and individuals to protect and enhance biodiversity while continuing to meet people's needs for natural resources. This challange exists from local to global scales. If not met, future generations will live in a biologically impoverished world and perhaps one that is less capable of producing desired resources as well.
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Conservation of Bio-Diversity
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(b) Ex situ conservation (outside habitats) This is done by establishment of gene banks, seed banks, zoos, botanical gardens, culture collections etc. Ex-situ Conservation: Ex-situ conservation means conservation of species (sample of genetic diversity), particularly of endangered species, away from their natural habitat under human supervision.The strategy of conservation of biodiversity is termed as 'ex-situ or off-site preservation'. In ex-situ conservation, the endangered species of animals are collected and bred under controlled conditions in zoos, game farms, aquaria, etc., while plant species are maintained in botanical gardens, .arboreta and seed banks. In situ Conservation: This type of conservation is mainly done for conservation of crop varieties, the wild relatives of crops and all the local varieties with the main objective of conserving the total genetic variability of the crop species for future crop improvement or afforestation programmes.
A national park is an area which is stricktly reserved by the betterment of the wild life and where activities such as forestry, grazing or cultivation are not permitted, and no private ownership is allowed. A national park is hitched to the habitat for particular wild animal species like, lion, tiger, rhinosorous, etc. and its boundaries are circumscribed by legislation. Except for the buffer zone (where limited human activity is allowed), no biotic interference is allowed.
Kaziranga
Assam
One horned Rhino
Gir National Park
Gujarat
Indian Lion
Dachigam
J&K
Hangul
Bandipur
Karnataka
Elephant
Periyar
Kerala
Elephant, Tiger
Kanha
M.P.
Tiger
Corbett
UP.
Tiger
BIOSPHERE RESERVE Multiple land use is permitted. A biosphere is not hitched to any one, two or morespecies, but to the whole ecosystem i.e. totality of all forms of life. In it, wild populations as well as traditional life styles of tribals and varied domesticated plant and animal genetic resources are protected.
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Important Wildlife
SCIENCE
State
ENVIRONMENTAL
Name of National park
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Some important National parks in India
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NATIONAL PARK
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In India, we have the following important gene bank/seed bank facilities: (i) National Bureau of Plant Genetic Resources (NBPGR) is located in New Delhi. Here agricultural and horticultural crops and their wild relatives are preserved by cryo-preservatioti of seeds, pollen etc. by using liquid nitrogen at a temperature as low as -196 °C. Varieties of rice, pearl millet, Brassica, turnip, radish, tomato, onion, carrot, chilli, tobacco, poppy etc. have been preserved successfully in liquid nitrogen for several years without losing seed viability.
// ENVIRONMENTAL
SCIENCE
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Endangered plants may also be preserved in part through seedbanks or germplasm banks. The term seedbank sometimes refers to a cryogenic laboratory facility in which the seeds of certain species can be preserved for up to a century or more without losing their fertility. It can also be used to refer to a special type of arboretum where seeds are harvested and the crop is rotated. For plants that cannot be preserved in seedbanks, the only other option for preserving germplasm is in-vitro storage, where cuttings of plants are kept under strict conditions in glass tubes and vessels.
ENGINEERING
(iii) National Facility for Plant Tissue Culture Repository (NFPTCR) for the development of a facility of conservation of varieties of crop plants/trees by tissue culture. This facility has been created within the NBPGR The G-15 countries have also resolved to set up a network of gene banks to facilitate the conservation of various varieties of aromatic and medicinal plants for which India is the networking co-ordinator country.
D.PARTHIBAN
(ii) National Bureau of Animal Genetic Resources (NBAGR) located at Karnal, Haryana. It preserves the semen of domesticated bovine animals.
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AIR POLLUTION WATER POLLUTION LAND POLLUTION MARINE POLLUTION NOISE POLLUTION THERMAL POLLUTION SOLID WASTE MANAGEMENT DISASTER MANAGEMENT
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ENVIRONMENTAL
CHAPTER-III PROVIDES INFORMATION ON:
SCIENCE
AND
ENGINEERING
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D.PARTHIBAN
ۼ܃۷ ܂െ ǣ ۳܄ۼ۷ۻۼ۽܀۳܂܃ۺۺ۽۾ۺۯ܂ۼ۷ۼ۽
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UNIT – 3 ENVIRONMENTAL POLLUTION
AIR POLLUTION-NOTES 1 Air pollution is the presence of contaminants in atmosphere in quantities such that it is injurious to human, plant animal life and property The main pollutants in the atmosphere are SO2 (sulphur dioxide), CO (carbon monoxide), oxides of nitrogen, particulate matter and lead. Sulphur dioxide: Sources: Combustion of fossil fuels – coal and crude oil contain up to 3% sulphur. Roasting of ores – sulphide ores on roasting, are converted to sulphur trioxide. This, when let into the atmosphere, combines with the moisture in the atmosphere to form sulphuric acid. for example, roasting of galena , the sulphide ore of lead 2PbS + 3O2 2PbO + 2SO2 2SO2 + O2 2SO3 H2O + SO3 H2SO4
Oxidation of l H2S – Hydrogen sulphide is formed during the decay of plants. This, on oxidation releases sulphur dioxide into the atmosphere. 2H2S + 3O2 2H2O + 2 SO2
Volcanic eruptions also emit sulphur dioxide.
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_____________________________ AIR POLLUTION_______________________________
ENGINEERING
o
AND
o
SCIENCE
o
Environmental Pollution Industrialization while bringing material benefits and comforts to the mankind has at the same time brought about deterioration in the environment. Besides increasing the concentration of certain material already present in the atmosphere, it has introduced in it new undesirable constituents. For instance, industrial units and various transport media constantly release into the atmosphere gases such as carbon monoxide, oxides of nitrogen and sulphur, which have a disastrous effect. In addition, natural causes such as earthquakes, volcanic eruptions and storms have also contributed to environmental pollution. The indiscriminate use of biotic and energy components at a rapid rate has caused further damage to the environment.
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o
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of SO2: Sulphur dioxide pollution in the atmosphere affects causes the following damages : In humans : it causes eye irritation, cough, lung diseases including lung cancer and asthma In plants: it causes damage of leaves, bleaching of chlorophyll which turns leaves brown, damage to crops and to growth of plants. Others: Yellowing of paper and wearing away of leather are other ill effects.
CO2 + C 2CO 2CO2
2CO + O2
effects: Haemoglobin in blood can form a complex with oxygen and hence functions as carrier of oxygen. When the atmosphere is polluted with carbon monoxide, on inhalation, CO combines with the hemoglobin to form carboxy haemoglobin and hence oxygen carrying capacity of the blood decreases. This causes, headache, dizziness, unconsciousness. When inhaled for a long duration it may cause even death. Control: Using catalytic converter in automobiles. Oxides of nitrogen
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Industries: carbon monoxide is released by industries such as iron and steel and petroleum .
AND
SCIENCE
2C + O2 2CO
ENVIRONMENTAL
Carbon monoxide Sources: Oxidation of methane: Methane is formed during decay of vegetable matter. Oxidation of methane releases carbon monoxide into the atmosphere. Automobile exhaust- carbon monoxide is formed during the combustion of fuel such as petrol and is released into the atmosphere through the exhaust Incomplete combustion of fossil fuels: coal when undergoes incomplete oxidation, forms carbon monoxide and pollutes the atmosphere.
D.PARTHIBAN
Control: The gases evolved during combustion of fossil fuels are passed through calcium carbonate when SO2 is converted to calcium sulphite. CaCO3 + SO2 CaSO3 + CO2 lime is added to coal and roasted at high temperature so that CaO formed combines with SO2 to form calcium sulphate. CaO + SO2 + ½ O2 CaSO4
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Nitric oxide, nitrogen dioxide and nitrous oxide are the three main oxides of nitrogen found in the atmosphere Sources: The sources for the oxides of nitrogen are: Bacterial decomposition of nitrogenous compounds – bacteria in the soil act on the ammonium compounds present in the soil, convert them to ammonia and finally release oxides of nitrogen into the atmosphere.
Control: Using catalytic converter in automobiles, Catalytic converters use Pt/ Rh catalyst. in the presence of the catalysts, the oxides of nitrogen are converted to nitrogen and oxygen . 2NOx N2 + x O2 Particulate matter Particulate matters are solid or liquid suspensions in air. They are also called aerosols. These comprise of dust particles, ash, smoke, fumes and mist.. Sources: Volcanic eruptions. Soil erosion: wind blows away soil and the dust particles are introduced into the atmosphere. Industrial operations such as crushing of solid materials- solid materials are crushed, ground and powdered in industries. During these operations dust is released into the atmosphere. Burning of coal: The noncombustible matter in coal is left behind as ash during the combustion of coal. Incomplete combustion of compounds containing carbon, processing of coal, cement asbestos: These operations also release dust into the atmosphere.
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// ENGINEERING AND
effects: Pollution due to oxides of nitrogen affects human and plant life: The oxides of nitrogen combine with moisture in the atmosphere to form nitrous and nitric acid. This leads to increase in the acidity of rain water F ormation of photochemical smog: oxides of nitrogen combine with hydrocarbons present in the atmosphere forming peroxyacyl nitrate. Peoxyacyl nitrate causes injury to plants and in human beings it causes fatigue and infection of the lungs Peroxyacyl nitrate formation leads to smog ( fog + smoke). Smog reduces visibility. Fading of dyes is caused in textiles .
SCIENCE
Combustion during lightning – during lightning, oxygen and nitrogen in the atmosphere combine to give oxides of nitrogen. N2 + O2 2NO 2NO + O2 2NO2 Industries and automobile exhaust - Air is sucked into the IC engines. At high temperatures, nitrogen and oxygen in the air combine to form nitric oxide. N2 + O2 2NO Nitric oxide escapes through the exhaust. It gets cooled rapidly and combines with oxygen in the air to give nitrogen dioxide. 2NO + O2 2NO2
ENVIRONMENTAL
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4NH3 + 5O2 4NO + 6H2O
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Mist – condensation of vapours, sprays etc lead to dispersion of liquids in the atmosphere thus forming mist.
Charged wire
Flue
Charged plate
Gas out
Dust
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ENVIRONMENTAL
SCIENCE
AND
ENGINEERING
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effects Presence of particulate matter in the atmosphere has the following effects: Decrease in visibility: Particulate matter interfere inn the transmission of light and hence affect visibility. Particulate matters enter the lungs causing wheezing, bronchitis, and asthma in human beings. In plants the particulate matter settle on the leaves blocking the stomata thereby affecting the plant growth. Control: Particulate matter in the atmosphere can be controlled using a. Gravitational settling chambers b. Centrifugal separators c. Fabric filters d. Wet scrubbers e. Electrostatic or Cottrell separators
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Gravitational settling chambers: figure (a) Here the flue gas is allowed into a rectangular settling tank at a slow rate so that the suspended particles in the gas get deposited. The particles are later removed.
Electrostatic or Cottrell separators: figure (e) The flue gas is passed into a chamber containing a series of charged plates. Between the plates wires charged to about 40000 volts are placed. As the flue gas passes through, the particles in it collide with the ionized gas molecules and the particles get charged. The positively charged particles now move towards the wire and get deposited. The negatively charged particles move towards the plates and settle. The gas which is now devoid of particulate matter goes out.
Lead pollutant Sources: The exhaust from automobiles which use lead tetraethyl as antiknocking agent when TEL is used as antiknocking agent, lead is converted to halide and released into the atmosphere. This leads to increase in the concentration of lead in the atmosphere. Paint pigments : Litharge and red lead ( oxides of lead ) and lead chromate are used as pigments. These cause lead pollution Plumbing systems- lead pipes are used for plumbing and these may cause lead pollution effects: Lead competes with calcium and enters the blood and bone marrow. The lead interferes in the manufacture of red blood corpuscles and abnormal multiplication of blood cells and thus leads to anaemia and blood cancer in human beings. Lead enters the blood and various organs of the body including the brain and the Kidneys leading to dysfunction of the kidney and damage to the brain.
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e.
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Wet scrubbers: figure (d) Flue gas is let into a chamber which has two sections – converging section and diverging section. The flue gas enters the converging section and water is sprayed from the top at right angles. The droplets of water take away the particulate matter in the gas.
ENGINEERING
d.
AND
c.
Centrifugal separators figure (b) With the help of a cyclone, the gas is led into a chamber tangential to the cross section of the chamber. The gas moves in a spiral manner. Due to the centrifugal forces, the particles in the gas move towards the wall of the chamber and get deposited. Fabric filters: figure (c) These consist of bags made of cotton, wool or artificial fibers ceramics. Theses can filter fine particulate matter. Flue gas is passed through a chamber containing a series of such bags. The particles are filtered and clean gas escapes. The particulates collect at the bottom and are removed periodically.
SCIENCE
b.
ENVIRONMENTAL
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AIR POLLUTANTS POLLUTNT
IMPOTANT FORM
Oxides of sulphur
SO2&H2SO4
2
Oxides of carbon
CO,CO2,particulate carbon
3
Oxides of nitrogen
NO,NO2,N2O,NO3
4
Volatile compounds
5
Secondary pollutants
1
CH4,alcohol, isoprene, Benzene, cresol, terpenes Photochemical oxidants like O3,N2O,PAN*
Metals
Pb, Hg, As, Cd
7
Halogen gases
Cl2,Br2,CH3Cl, CH3Br,PCB,CFC,
Transportation, Fossil fuel, transportation, power plants, petroleum refineries, burning of oil, coal, fertilizers Transportation, power plants, petroleum refineries, burning of oil, coal Reaction between primary pollutants by sun light Leaded petrol, ore processing unit, coal power plants, garbage incinerators, ore smelting Industrial chemicals, plastics burning, coal burning, biomass burning, fumigants.
One of the formal definitions of air pollution is as follows – ‘The presence in the atmosphere of one or more contaminants in such quality and for such duration as is injurious, or tends to be injurious, to human health or welfare, animal or plant life.’ It is the contamination of air by the discharge of harmful substances. Air pollution can cause health problems and it can also damage the environment and property. It has caused thinning of the protective ozone layer of the atmosphere, which is leading to climate change.
Modernization and progress have led to air getting more and more polluted over the years. Industries, vehicles, increase in the population, and urbanization are the major factors responsible for air pollution. The following industries are among those that emit a great deal of pollutants into the
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SCIENCE
Air and its major pollutants
ENVIRONMENTAL
AIR POLLUTION-NOTES 2
ENGINEERING
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6
SOURCES Coal industries, mining, ore processing
D.PARTHIBAN
S.NO
Page: air: thermal power plants, cement, steel, refineries, petro chemicals, and mines. Air pollution results from a variety of causes, Dust storms in desert areas and smoke from forest fires and grass fires contribute to chemical and particulate pollution of the air. The source of pollution may be in one country but the impact of pollution may be felt elsewhere. The discovery of pesticides in Antarctica, where they have never been used, suggests the extent to which aerial transport can carry pollutants from one place to another. Probably the most important natural source of air pollution is volcanic activity, which at times pours great amounts of ash and toxic fumes into the atmosphere. The eruptions of such volcanoes as Krakatoa in Indonesia, Mt. St. Helens in Washington, USA and Katmai in Alaska, USA, have been related to measurable climatic changes.
National Ambient Air Quality Standards POLLUTANTS
Annual average
CONCENTRATION 60 µg/m3
24 hour
80 µg/m3
A.A
60 µg /m3
24H
80 µg /m3
A.A
140 µg/m3
24H
200 µg/m3
A.A
0.75 µg/m3
24H
1.0 µg/m3
A.A
2.0 µg/m3
24H
4.0 µg/m3
A.A
60 µg/m3
24H
100 µg/m3
Lead
Carbon Monoxide
AND
Suspended Particulate Matter (SPM)
SCIENCE
Oxides of Nitrogen (NO2)
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Sulphur dioxide (SO2)
AVERAGE TIME
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Listed below are the major air pollutants and their sources.
Carbon monoxide (CO) is a colourless, odourless gas that is produced by the incomplete burning of carbon-based fuels including petrol, diesel, and wood. It is also produced from the combustion of natural and synthetic products such as cigarettes. It lowers the amount of oxygen that enters our blood. It can slow our reflexes and make us confused and sleepy. Carbon monoxide (CO) is an odorless, colorless, poisonous gas that comes mainly from motor vehicles and other combustion exhaust. It cannot
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ENVIRONMENTAL
Respirable Particulate Matter (RPM)
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be seen [colorless] or smelled [odorless]. Carbon monoxide is released when engines burn fossil fuels. Emissions are higher when engines are not tuned properly, and when fuel is not completely burned. Cars emit a lot of the carbon monoxide found outdoors. Furnaces and heaters in the home can emit high concentrations of carbon monoxide, too, if they are not properly maintained
Health effects:
Carbon monoxide interferes with the blood's ability [by forming carboxy hemoglobin] to carry oxygen to the brain, heart and other tissues, and it is particularly dangerous for people with existing heart disease, and unborn or newborn children. Carbon monoxide makes it hard for body parts to get the oxygen they need to run correctly. Exposure to carbon monoxide makes people feel dizzy and tired and gives them headaches.
THE GASEOUS COMPOSITION OF UNPOLLUTED AIR
Parts per million (vol)
Nitrogen
756,500
Oxygen
202,900
Water
31,200
Argon
9,000
Carbon Dioxide
305
Methane
0.97-1.16
Krypton
0.97
Nitrous oxide
0.49
Hydrogen
0.49
Xenon
0.08
Organic vapors
ca.0.02
Chlorofluorocarbons (CFC) are gases that are released mainly from air-conditioning systems and refrigeration. When released into the air, CFCs rise to the stratosphere, where they come in contact with few other gases, which lead to a reduction of the ozone layer that protects the earth from the harmful ultraviolet rays of the sun. Ozone
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5.0
SCIENCE
17.4
ENVIRONMENTAL
Neon Helium
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The Gases
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Note: Harmful ozone in the lower atmosphere should not be confused with ozone in the upper atmosphere, which protects us from ultraviolet radiation. Since UV radiation is very dangerous to human beings Health effects:
Ozone reacts with lung tissue. It can inflame and cause harmful changes in breathing passages, decrease the lungs' working ability and cause both coughing and chest pains. People who exercise are also more vulnerable to the effects of ozone, suffering symptoms and a reduced ability to breathe at relatively low ozone levels. Ozone pollution, even at low levels, has also been linked to increased hospital admissions and emergency room visits for respiratory problems
Nitrogen oxide (NOx)
Nitrogen oxide causes smog and acid rain. It is produced from burning fuels including petrol, diesel, and coal. Nitrogen oxides can make children susceptible to respiratory diseases in winters. A reddish-brown gas that comes from the burning of fossil fuels. It has a strong smell at high levels. Nitrogen dioxide mostly comes from power plants and cars. Nitrogen dioxide is formed in two ways‚—when nitrogen in the fuel is burned, or when nitrogen in the air reacts with oxygen at very high temperatures. Nitrogen dioxide can also react in the atmosphere to form ozone, acid rain, and particles.
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ENGINEERING
Ozone gas that can be found in two places. Near the ground (the troposphere), it is a major part of smog. Higher in the air (the stratosphere), it helps block radiation from the sun. Ozone is not created directly, but is formed when nitrogen oxides and volatile organic compounds mix in sunlight. That is why ozone is mostly found in the summer. Nitrogen oxides come from burning gasoline, coal, or other fossil fuels. There are many types of volatile organic compounds, and they come from sources ranging from factories to trees. Ozone near the ground can cause a number of health problems. Ozone can lead to more frequent asthma attacks in people who have asthma and can cause sore throats, coughs, and breathing difficulty. It may even lead to premature death. Ozone makes our eyes itch, burn, and water. It lowers our resistance to colds and pneumonia Ozone can also hurt plants and crops. Ozone (O3) is the major harmful ingredient in smog. Major sources include refineries, gas stations, motor vehicles, chemical plants, paints and solvents.
AND
SCIENCE
Ozone occurs naturally in the upper layers of the atmosphere. This important gas shields the earth from the harmful ultraviolet rays of the sun. However, at the ground level, it is a pollutant with highly toxic effects. Vehicles and industries are the major source of ground-level ozone emissions.
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Health effects: Nitrogen dioxide has a variety of environmental and health impacts. It is a respiratory irritant, may exacerbate asthma and possibly increase susceptibility to infections. In the presence of sunlight, it reacts with hydrocarbons to produce photochemical pollutants such as ozone (see below). In addition, nitrogen oxides have a lifetime of approximately 1 day with respect to conversion to nitric acid. This nitric acid is in turn removed from the atmosphere by direct deposition to the ground, or transfer to aqueous droplets (e.g. cloud or rainwater), thereby contributing to acid deposition.
Suspended particulate matter (SPM) It consists of solids in the air in the form of smoke, dust, and vapour that can remain suspended for extended periods and is also the main source of haze which reduces visibility. The finer of these particles, when breathed in can lodge in our lungs and cause lung damage and respiratory problems. They are Solid or liquid matter that is suspended in the air. To remain in the air, particles are usually less than 0.1 mm wide and can be as small as 0.00005 mm. Particulate matter can be divided into two types-coarse particles and fine particles. Coarse particles are bigger than 0.002 mm and are formed from sources like road dust, sea spray, and construction. Fine particles are smaller than 0.002 mm and are formed when fuel is burned in automobiles and power plants. Particulate matter (PM) includes microscopic particles and tiny droplets of liquid. These particles come from the burning of fuels by industry and diesel vehicles and from earth-moving activities such as construction and mining. Health effects: Larger particles can be stopped in the nose and upper lungs by the body's natural defenses. The smallest particles escape the body's defenses and go deep into the lungs, where
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Nitrogen oxides are released into the atmosphere mainly in the form of NO, which is then readily oxidised to NO2 by reaction with ozone. Elevated levels of NOx occur in urban environments under stable meteorological conditions, when the air mass is unable to disperse. Whereas nitrogen dioxide (NO2) participates in the formation of ozone, nitrogen oxide (NO) destroys ozone to form oxygen (O2) and nitrogen dioxide (NO2). As the nitrogen oxides and hydrocarbons are transported out of urban areas, the ozone-destroying NO is oxidised to NO2, which participates in ozone-formation.
ENGINEERING
AND
SCIENCE
Nitrogen oxides are formed during high temperature combustion processes from the oxidation of nitrogen in the air or fuel. The principal source of nitrogen oxides - nitric oxide (NO) and nitrogen dioxide (NO2), collectively known as NOx - is road traffic, which is responsible for approximately half the emissions in Europe. NO and NO2 concentrations are therefore greatest in urban areas where traffic is heaviest. Other important sources are power stations, heating plants and industrial processes.
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they may become trapped. Exposure to particulate pollution can cause wheezing and other symptoms in people with asthma or sensitive airways. Particulate pollution has been linked to increased hospital admissions and emergency room visits for respiratory problems and to a substantial increase in premature deaths Sulphur dioxide (SO2)
Sulphur dioxide is a gas produced from burning coal, mainly in thermal power plants. Some industrial processes, such as production of paper and smelting of metals, produce sulphur dioxide.
It is a major contributor to smog and acid rain. Sulfur dioxide can lead to lung diseases. It’s a corrosive gas that cannot be seen or smelled at low levels but can have a
Health effects:
Sulphur dioxide is a corrosive acid gas which combines with water vapour in the atmosphere to produce acid rain.
Both wet and dry deposition has been implicated in the damage and destruction of vegetation and in the degradation of soils, building materials and watercourses.
SO2 in ambient air is also associated with asthma and chronic bronchitis. Sulfur dioxide exposure can affect people who have asthma or emphysema by making
it more difficult for them to breathe. It can also irritate people's eyes, noses, and throats. Sulfur dioxide can harm trees and crops, damage buildings, and make it harder for people to see long distances.
LEAD
Lead is the most widely used non-ferrous metal and has a large number of industrial
applications. Lead comes from cars in areas where unleaded gasoline is not used. Lead can also come from power plants and other industrial sources. Lead paint is an important source of lead, especially in houses where paint is peeling.
Lead in old pipes can also be a source of lead in drinking water.
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for domestic heating, in industry and in power stations. As some power stations are now located away from urban areas, SO2 emissions may effect air quality in both rural and urban areas
ENGINEERING
sulphur.
Major SO2 problems now only tend to occur in cities in which coal is still widely used
AND
The principal source of this gas is power stations burning fossil fuels which contain
SCIENCE
and particles.
ENVIRONMENTAL
Sulfur dioxide mostly comes from the burning of coal or oil in power plants. It also comes from factories that make chemicals, paper, or fuel. Like nitrogen dioxide, sulfur dioxide also reacts in the atmosphere to form acid rain
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“rotten egg” smell at high levels.
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Its single largest industrial use world-wide is in the manufacture of batteries (60-70%
of total consumption of some 4 million tones) and it is also used in paints, glazes, alloys, radiation shielding, tank lining and piping. As tetraethyl lead, it has been used for many years as an additive in petrol; most airborne emissions of lead in Europe therefore originate from petrol-engine motor vehicles. With the increasing use of unleaded petrol, however, emissions and concentrations in air have declined steadily in recent years.
Health effects:
Lead is a cumulative poison to the Central Nervous System, particularly detrimental to the mental development of children.
High amounts of lead can be dangerous for small children and can lead to lower IQs and kidney problems.
For adults, exposure to lead can increase the chance of having heart attacks or
Water exists in three states: solid, liquid and gaseous. The important sources of water are (i) rain water, (ii) ground water and (iii) sea water. Rain water carries the washed out minerals, salts and organic matter from the earth’s surface and stores them in ponds, lakes and rivers. It seeps into underground and is stored as ground water. Sea water is highly alkaline due to the presence of dissolved salts. The natural water contains numerous organisms and dissolved gases (ex: oxygen), which is essential for aquatic organisms. The pure water is one which is free from organisms. Water is required mainly for drinking and cooking, also for industry, agriculture and many other activities. Pollution of water implies that it contains a lot of inorganic and organic substances introduced by human activities, which change its quality, not suitable for any purposes and also harmful for living organisms. (or) Any alteration in physical, chemical or biological properties of water, as well as the addition of any foreign substance makes it unfit for health and which decreases the utility of water, is known as water pollution.
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SCIENCE
Introduction
ENVIRONMENTAL
WATER POLLUTION –NOTES # 1
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ENGINEERING
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_____________________________ WATER POLLUTION____________________________
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The substances which cause pollution are called pollutants and the common pollutants which are present in water are (i) Suspended solids (ii) Organic matter, (iii) Inorganic pollutants, (iv) Oil, etc. Turbidity in water is mainly due to; (i) finely divided undissolved solids, clay, slit; (ii) colloidal particles and (iii) organic matters. Turbidity gives unsightly appearance. When it is used in industries, it causes problems in functioning of equipments, boilers, etc. This can be removed from water by applying proper treatments like settling, coagulation (by using alum) and filtration. Organic pollutants include domestic and animal sewage, biodegradable organic compounds, industrial wastes, synthetic pesticides, fungicides, herbicides, detergents, oil, grease, pathogenic microorganisms, etc. It results in rapid depletion of dissolved oxygen of water and thus such water becomes harmful for aquatic lives. Organic matter present in water can be removed by using chlorination, coagulation and ultra filtration processes. Inorganic pollutants consist of mineral acids, inorganic salts, finely divided metals, cyanides, sulphates, nitrates, organometallic compounds, etc. Oil and grease constitutes important water pollutants. These substances coat ion exchange resin, causes premature exhaustion of beds. It can be removed by coagulation with alum.
Sources and ill effects of heavy metals and inorganic species
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// ENGINEERING AND
SCIENCE
Domestic sewage consists of human excreta, street wastes, organic substances that provide nutrition for bacteria and fungi. It is grey green or grey yellow in color and darkens with time due to decomposition, when becomes stale it develops offensive odor due to evolution of gases like NH3, H2S, etc. It is normally turbid due to the presence of suspended solids. Its temperature is slightly higher than ordinary water. These pollutants cause many hazardous effects on health. Discharge of sewage in river and lakes spreads water borne diseases. A pollutant present in industrial waste water damages biological activities and kills many useful organisms. Most of the industrial wastes dissolved in water are particulate in nature and are present at the bottom of the water system. These acts as poison for the aquatic organisms. Further, toxic metals present in industrial effluents are extremely hazardous for living beings. Agricultural discharge consists of pesticides, fertilizers, insecticides, etc. In agriculture in order to increase the production and to escape the crops from various diseases, the fertilizers and insecticides are used. Any substance or a mixture of substances which prevents, repels, destroys any pest is called a pesticide. These pollutants contaminate the water and when this is used by human being, affect the oxygen carrying capacity of hemoglobin and consequently causes suffocation and irritation to respiratory and vascular system. Radioactive wastes are mainly from atomic explosion and processing of radioactive materials near the source of water. The other sources are waste from hospitals, research laboratories, etc. The radioactive pollutants in water cause serious skin cancer, carcinoma, leukemia, DNA breakage, etc. Water pollution by heavy metals: About 70 metallic elements are called heavy metals, as they have atomic numbers of 22 to 92 and atomic weight higher than that of sodium and with a specific gravity of more than 5.0. Only a few of these heavy metals are considered potentially damaging to living systems.
ENVIRONMENTAL
D.PARTHIBAN
Main sources of water pollution are (i) domestic and municipal sewage; (ii) industrial waste; (iii) agricultural waste; (iv) radioactive materials, etc.
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Sources
Their effects
Cd
Discharges from electroplating industries, Battery manufacturing units, metallurgical industries, etc.
Gets adsorbed on suspended matter in the water, when it is consumed causes liver and kidney necrosis, increased salivation nausea, acute gastritis, etc.
Hg
Effluents from chloro-alkali industries, pesticide industries, Chemical industries, etc.
Cyanide is extremely toxic. Exposure even to small quantities over longer periods causes loss of apatite, dizziness, etc.
NH3
Ammonia is generated by the biological decay, reduction of nitrates under anaerobic conditions.
In high concentration, it is toxic to fish and other aquatic organisms. It imparts characteristic odor to water.
By bacterial reduction of sulphate and decomposition of organic matter.
Causes corrosion, imparts bad odor.
H2S
Sewage treatment The polluted water is characterized by its oxygen demand and solid content. The biological oxygen demand (BOD) measures the level of organic pollution in the sewage water. The sewage must be treated before being discharged into the water bodies. The treatment is carried out in three stages- primary, secondary and tertiary. (i) (ii)
In primary treatment, the suspended solids and floating objects are removed using coarse screens and sieves. In secondary treatment, the maximum proportions of the suspended inorganic/ organic solids are removed from the liquid sewage. The liquid material passes into the sedimentation tank and
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Metal finishing and cleaning, electroplating, coke ovens and many other industrial processes generate cyanide and discharge as effluent to water bodies.
ENGINEERING
CN-
AND
A cumulative poison causing loss of apatite, constipation, abdominal pain, mental retardation, nervous disorder and brain damage.
Pb
SCIENCE
Electric storage battery industries, petroleum industries, ceramic industries, electric cable insulation, paint industries, plastic industries, pesticides, pipe-manufacturing units, etc.
D.PARTHIBAN
Mercury poisoning causes kidney damage, and exhibits the symptoms like numbness in the limbs, muscles, blurred vision leading to blindness, emotional disturbances etc. It also damages brain and nervous system, and paralysis followed by death.
ENVIRONMENTAL
Heavy Metal
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finely suspended particles are allowed to settle by adding coagulants like Alum. The suspended materials settle down in the tanks and forms sludge. The sewage water after sedimentation process is allowed for aerobic oxidation. The organic matter is converted into CO2, the nitrogen into NH3 and nitrites to nitrates. The treatment is carried out by activated sludge process. The above process is based on the principle that if an adequate amount of oxygen / air is passed through the sewage containing aerobes, complete aerobic oxidation occurs. This oxidation process becomes speedy by the addition of a part of sludge from the previous process, called activated sludge. Settled sludge is sent back for feeding fresh bulk of sewage, while the remainder is disposed off by land spreading, sea burial etc.
It is expressed in parts per million (ppm) or mg/dm3. Larger the concentration of decomposable organic matter, greater is the BOD and consequently more is the nuisance value. Strictly aerobic conditions are required. Determination is slow and time consuming.
Determination BOD
The method is based on the determination of dissolved oxygen before and after 5 days period, at 20oC. A known volume of sample of sewage is diluted with known volume of water containing nutrients for bacterial growth, whose dissolved oxygen content is predetermined. The whole solution is incubated in a closed bottle at 20oC for 5 days. After incubation the unused oxygen is determined. The difference between the original value of oxygen content in the diluted water and unused oxygen of solution after 5 days gives BOD.
CHEMICAL OXYGEN DEMAND (COD) COD is a measure of oxidisable sewage. It includes both the biologically oxidisable and biologically inert matter such as cellulose, as a result of which the value of COD is more than BOD. COD is defined as the
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// ENGINEERING
Characteristics of BOD
AND
It is defined as the amount of oxygen required for the biological oxidation of the organic matter under aerobic conditions at 20oC and for a period of 5 days.
SCIENCE
BIOLOGICAL OXYGEN DEMAND
ENVIRONMENTAL
The treated water is of high clarity, free from odor and low BOD, therefore it is nearly equivalent to drinking water.
D.PARTHIBAN
Tertiary treatment is applied to remove detergents, metal ions, nitrates and pesticides, as these are not removed in the earlier treatments. The phosphates are removed as calcium phosphates by adding calcium hydroxide at pH 10-11. At this pH, ammonium salts are also converted into ammonia. Fine particles are further removed by sedimentation in the presence of coagulants. The effluent is chlorinated to remove pathogenic bacteria’s and finally passed through activated charcoal to absorb gases.
(iii)
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amount of oxygen (in ppm) consumed under specified conditions, while oxidizing total organic load of the sample with a strong oxidizing agent (Ex: potassium dichromate) in the acid medium. Determination COD
A definite volume of waste water sample (‘x’ ml) is refluxed with a known volume of K2Cr2O7 in H2 SO4 medium in the presence of AgSO4 (which acts as a catalyst) and HgSO4 (which eliminates interference due to chlorine). K2Cr2O7 oxidises all organic matter into water, CO2 and ammonia. The unreacted dichromate is titrated with a standard solution of ferrous ammonium sulphate (FAS) (Let the volume consumed is v2 ml). COD =
(v1 v 2 ) N FAS 8 1000 ; x
v1 corresponds to the volume of FAS consumed in the blank
High level exposure to fluoride can lead to skeletal fluorosis (photos). Here, fluoride accumulates in the bone progressively over many years. The early symptoms of skeletal fluorosis include stiffness and pain in the joints. In severe cases the bone structure may change and ligaments may calcify resulting impairment of muscles and pain. Acute high level results in abdominal pain excessive saliva, nausea and vomiting. Dental Fluorosis Skeletal Fluorosis
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Fluorosis is caused by excessive intake of fluoride. The dental effects of fluorosis develop made earlier than the skeletal effects in people exposed to large amounts of fluoride. Clinical dental fluorosis is characterized by staining and pitting of teeth. In more severe cases all the enamel may be damaged.
SCIENCE
Ingestion of excess fluoride, most commonly in drinking water can cause fluorosis which affects the teeth (dental) (see photo) and bones (skeletal). Moderate amounts lead to dental effects, but long term ingestion of large amounts can lead to potentially severe skeletal problems.
ENVIRONMENTAL
Fluoride Problem in Drinking Water Fluorosis Fluoride in water is mostly of geological origin. Waters with high levels of fluoride content are mostly found at the foot of high mountains and in areas where seas has made geological deposits.
D.PARTHIBAN
titration (i.e., in the absence of waste water sample).
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Cause
INTRODUCTION
Comprising over 70% of the Earth’s surface, water is undoubtedly the most precious natural resource that exists on our planet. Without the seemingly invaluable compound comprised of hydrogen and oxygen, life on Earth would be non-existent: it is essential for everything on our planet to grow and prosper. Although we as humans recognize this fact, we disregard it by polluting our rivers, lakes, and oceans. Subsequently, we are slowly but surely harming our planet to the point where organisms are dying at a very alarming rate. In addition to innocent organisms dying off, our drinking water has become greatly affected as is our ability to use water for recreational purposes. In order to combat water pollution, we must understand the problems and become part of the solution.
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ENVIRONMENTAL
WATER POLLUTION –NOTES # 1
SCIENCE
AND
Acute high level is very rare and usually due to accidental contamination of drinking water. Moderate level chronic exposure (>1.5 mg/l) is more common. People affected by fluorosis are often exposed to multiple sources of fluorosis, such as in food, water, air and excessive toothpaste. However, drinking water is typically the most significant source.
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POINT AND NONPOINT SOURCES According to the American College Dictionary, pollution is defined as: “to make foul or unclean; dirty.” Water pollution occurs when a body of water is adversely affected due to the addition of large amounts of materials to the water. When it is unfit for its intended use, water is considered polluted. Two types of water pollutants exist; point source and nonpoint source. Point sources of pollution occur when harmful substances are emitted directly into a body of water. The Exxon Valdez oil spill best illustrates point source water pollution. A non-point source delivers pollutants indirectly through environmental changes. An example of this type of water pollution is when fertilizer from a field is carried into a stream by rain, in the form of runoff which in turn affects aquatic life. The technology exists for point sources of pollution to be monitored and regulated, although political factors may complicate matters. Nonpoint sources are much more difficult to control. Pollution arising from nonpoint sources accounts for a majority of the contaminants in streams and lakes.
// ENGINEERING AND
This, in turn, proves very harmful to aquatic organisms as it affects the respiration ability or fish and other invertebrates that reside in water. Pollution is also caused when silt and other suspended solids, such as soil, wash off plowed fields, construction and logging sites, urban areas, and eroded river banks when it rains. Under natural conditions, lakes, rivers, and other water bodies undergo Eutrophication, an aging process that slowly fills in the water body with sediment and organic matter. When these sediments enter various bodies of water, fish respiration becomes impaired, plant productivity and water depth become reduced, and aquatic organisms and their environments become suffocated. Pollution in the form of organic material enters waterways in many different forms as sewage, as leaves and grass clippings, or as runoff from livestock feedlots and pastures. When natural bacteria and protozoan in the water break down this organic material, they begin to use up the oxygen dissolved in the water. Many types of fish and bottom-dwelling animals cannot survive when levels of dissolved oxygen drop below two to five parts per million. When this occurs, it kills aquatic organisms in large numbers which leads to disruptions in the food chain.
SCIENCE
Many causes of pollution including sewage and fertilizers contain nutrients such as nitrates and phosphates. In excess levels, nutrients over stimulate the growth of aquatic plants and algae. Excessive growth of these types of organisms consequently clogs our waterways, use up dissolved oxygen as they decompose, and block light to deeper waters.
D.PARTHIBAN
CAUSES OF POLLUTION
The pollution of rivers and streams with chemical contaminants has become one of the most crucial environmental problems within the 20th century. Waterborne chemical pollution entering rivers and streams cause tremendous amounts of destruction.
Pathogens are another type of pollution that proves very harmful. They can cause many illnesses that range from typhoid and dysentery to minor respiratory and skin diseases. Pathogens include such organisms as bacteria, viruses, and protozoan. These pollutants enter waterways through untreated sewage, storm drains, septic tanks, runoff from farms, and
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ENVIRONMENTAL
Polluted River in the United Kingdom
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particularly boats that dump sewage. Though microscopic, these pollutants have a tremendous effect evidenced by their ability to cause sickness ___________________________________. .
Demonstrators Protest Drilling
Workers use special nets to clean up a California beach after an oil tanker spill. Tanker spills are an increasing environmental problem because once oil has spilled, it is virtually impossible to completely remove or contain it. Even small amounts spread rapidly across large areas of water. Because oil and water do not mix, the oil floats on the water and then washes up on broad expanses of shoreline. Attempts to chemically treat or sink the oil may further disrupt marine and beach ecosystems.
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ENVIRONMENTAL
Oil Spill Clean-up
SCIENCE
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ENGINEERING
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D.PARTHIBAN
Oil pollution is a growing problem, particularly devastating to coastal wildlife. Small quantities of oil spread rapidly across long distances to form deadly oil slicks. In this picture, demonstrators with "oil-covered" plastic animals protest a potential drilling project in Key Largo, Florida. Whether or not accidental spills occur during the project, its impact on the delicate marine ecosystem of the coral reefs could be devastating.
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In recent years, however, more stress has been placed on improving means of disposal of the solid residues from the municipal treatment processes.
The basic methods of treating municipal wastewater fall into three stages: primary treatment, including grit removal, screening, grinding, and sedimentation; secondary treatment, which entails oxidation of dissolved organic matter by means of using biologically active sludge, which is then filtered off; and tertiary treatment, in which advanced biological methods of nitrogen removal and chemical and physical methods such as granular filtration and activated carbon absorption are employed.
The handling and disposal of solid residues can account for 25 to 50 percent of the capital and operational costs of a treatment plant.
The characteristics of industrial waste waters can differ considerably both within and among industries. The impact of industrial discharges depends not only on their collective characteristics, such as biochemical oxygen demand and the amount of suspended solids, but also on their content of specific inorganic and organic substances.
Three options are available in controlling industrial wastewater. Control can take place at the point of generation in the plant; wastewater can be pretreated for discharge to municipal treatment sources; or wastewater can be treated completely at the plant and either reused or discharged directly into receiving waters.
TIPS: SAVING THE WATER AND PREVENTING POLLUTION a. b. c. d. e. f. g. h.
Take shorter shower. Don’t flush every time you use the toilet. Don’t open the tap while you are brushing the teeth or washing dishes Uses water conserving home appliances-low flow shower, low flush toilet. Repair water leaking in the water pipes. Immerse a solid material in the flush tank to reduce the volume of water in each flush Plant low maintenance crops that utilizes less amount of water for growing. Dispose the used motor oil, household hazardous wastes and batteries.
WATER POLLUTANTS S.No
TYPE
EXAMPLES
SOURCES
1
Pathogens
Bacteria, viruses, parasites
Human and animal excreta
2
Radioactive materials
Uranium, thorium, cesium, polonium
Atomic power plant, mining operation
3
Organic chemicals
Insecticides, detergents,
Industrial wastes,
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ENGINEERING
For many years, the main goal of treating municipal wastewater was simply to reduce its content of suspended solids, oxygen-demanding materials, dissolved inorganic compounds, and harmful bacteria.
AND
SCIENCE
The major sources of water pollution can be classified as municipal, industrial, and agricultural.Municipal water pollution consists of waste water from homes and commercial establishments.
ENVIRONMENTAL
D.PARTHIBAN
CLASSIFYING WATER POLLUTION
Industrial effluents
5
O2 demanding wastes
Animal manure and plant wastes
Domestic sewage, paper and pulp industries, food industries, agricultural runoff
6
Thermal
Heat energy
Power plants, furnaces, cooling towers
7
sediments
Soil, silt
Land erosion and land degradation
8
Plant nutrients
N,P,K fertilizers
Agricultural runoff, fertilizer industries
Wastewater Treatment o
o
o o o
o o o o o
Raw sewage includes waste from sinks, toilets, and industrial processes. Treatment of the sewage is required before it can be safely buried, used, or released back into local water systems. In a treatment plant, the waste is passed through a series of screens, chambers, and chemical processes to reduce its bulk and toxicity. The three general phases of treatment are primary, secondary, and tertiary. During primary treatment, a large percentage of the suspended solids and inorganic material is removed from the sewage. The focus of secondary treatment is reducing organic material by accelerating natural biological processes. Tertiary treatment is necessary when the water will be reused; 99 percent of solids are removed and various chemical processes are used to ensure the water is as free from impurity as possible. Agriculture, including commercial livestock and poultry farming, is the source of many organic and inorganic pollutants in surface waters and groundwater. These contaminants include both sediment from erosion cropland and compounds of phosphorus and nitrogen that partly originate in animal wastes and commercial fertilizers. Animal wastes are high in oxygen demanding material, nitrogen and phosphorus, and they often harbor pathogenic organisms. Wastes from commercial feeders are contained and disposed of on land; their main threat to natural waters, therefore, is from runoff and leaching. Control may involve settling basins for liquids, limited biological treatment in aerobic or anaerobic lagoons. A variety of other methods can be employed in order to treat run off from industries.
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Acids, solvents, bases, ionic salts, metallic compounds
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Inorganic chemicals
ENGINEERING
4
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agricultural runoff
SCIENCE
plastics, petrol
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Waste-water treatment:
1. Screening: Wastewater entering the treatment plant includes items like wood, rocks, and even dead animals. Unless they are removed, they could cause problems later in the treatment process. Most of these materials are sent to a landfill.
One of the first steps that a water treatment facility can do is to just shake up the sewage and expose it to air. This causes some of the dissolved gases (such as hydrogen sulfide, which smells like rotten eggs) that taste and smell bad to be released from the water. Wastewater enters a series of long, parallel concrete tanks. Each tank is divided into two sections. In the first section, air is pumped through the water. As organic matter decays, it uses up oxygen. Aeration replenishes the oxygen. Bubbling oxygen through the water also keeps the organic material suspended while it forces 'grit' (coffeegrounds, sand and other small, dense particles) to settle out. Grit is pumped out of the tanks and taken to landfills. 4. Removing sludge: Wastewater then enters the second section or sedimentation tanks. Here, the sludge (the organic portion of the sewage) settles out of the wastewater and is pumped out of the tanks. Some of the water is removed in a step called thickening and then the slud sludge ge is processed in large tanks called digesters. 5. Removing scum: As sludge is settling to the bottom of the sedimentation tanks, lighter materials are floating to the surface. This 'scum' includes grease, oils, plastics, and soap. Slow Slow-moving moving rakes skim the th scum off the surface of the wastewater. Scum is thickened and pumped to the digesters along with the sludge. Many cities also use filtration in sewage treatment. After the solids are removed, the
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// ENGINEERING
Aerating:
AND
3.
SCIENCE
The wastewater system relies on the for force ce of gravity to move sewage from your home to the treatment plant. So wastewater wastewater-treatment treatment plants are located on low ground, often near a river into which treated water can be released. If the plant is built above the ground level, the wastewater has to be e pumped up to the aeration tanks (item 3). From here on, gravity takes over to move the wastewater through the treatment process.
D.PARTHIBAN
Pumping:
ENVIRONMENTAL
2.
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liquid sewage is filtered through a substance, usually san sand, d, by the action of gravity. This method gets rid of almost all bacteria, reduces turbidity and color, removes odors, reduces the amount of iron, and removes most other solid particles that remained in the water. Water is sometimes filtered through carbon particles, which removes organic particles. This method is used in some homes, too. 6. Killing bacteria. Finally, the wastewater flows into a 'chlorine contact' tank, where the chemical chlorine is added to kill bacteria, which could pose a health risk, ju just st as is done in swimming pools. The chlorine is mostly eliminated as the bacteria are destroyed, but sometimes it must be neutralized by adding other chemicals. This protects fish and other marine organisms, which can be harmed by the smallest amounts of chlorine. The treated water (called effluent) is then discharged to a local river or the ocean.
ENVIRONMENTAL
SCIENCE
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ENGINEERING
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an other part of treating wastewater is dealing with the solid solid-waste waste material. These solids are kept for 20 to 30 days in large, heated and enclosed tanks called 'digesters.' Here, bacteria break down (digest) the material, reducing its volume, odors, and get getting ting rid of organisms that can cause disease. The finished product is mainly sent to landfills, but sometimes can be used as fertilizer.
D.PARTHIBAN
R. Wastewater Residuals.
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ENVIRONMENTAL
SCIENCE
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ENGINEERING
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ENVIRONMENTAL
SCIENCE
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ENGINEERING
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ENVIRONMENTAL
SCIENCE
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ENGINEERING
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D.PARTHIBAN
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TRICKLING FILTER
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GROUND WATER
Ninety-five percent of all fresh water on earth is ground water. Ground water is found in natural rock formations. These formations, called aquifers, are a vital natural resource with many uses. Nationally, 53% of the population relies on ground water as a source of drinking water. In rural areas this figure is even higher. Eighty one percent of community water is dependent on ground water. Although the 1992 Section 305(b) State Water Quality Reports indicate that, overall, the Nation’s ground water quality is good to excellent; many local areas have experienced significant ground water contamination. Some examples are leaking underground storage tanks and municipal landfills.
// ENGINEERING ENVIRONMENTAL
Estimates suggest that nearly 1.5 billion people lack safe drinking water and that at least 5 million deaths per year can be attributed to waterborne diseases. With over 70 percent of the planet covered by oceans, people have long acted as if these very bodies of water could serve as a limitless dumping ground for wastes. Raw sewage, garbage, and oil spills have begun to overwhelm the diluting capabilities of the oceans, and most coastal waters are now polluted. Beaches around the world are closed regularly, often because of high amounts of bacteria from sewage disposal, and marine wildlife is beginning to suffer.
AND
GLOBAL WATER POLLUTION
SCIENCE
Several forms of legislation have been passed in recent decades to try to control water pollution. In 1970, the Clean Water Act provided 50 billion dollars to cities and states to build wastewater facilities. This has helped control surface water pollution from industrial and municipal sources throughout the United States. When congress passed the Clean Water Act in 1972, states were given primary authority to set their own standards for their water. In addition to these standards, the act required that all state beneficial uses and their criteria must comply with the “fishable and swimmable” goals of the act. This essentially means that state beneficial uses must be able to support aquatic life and recreational use. Because it is impossible to test water for every type of disease-causing organism, states usually look to identify indicator bacteria. One for a example is a bacteria known as fecal coliforms. (Figure 1 shows the quality of water for each every state in the United States, click on the US link). These indicator bacteria suggest that a certain selection of water may be contaminated with untreated sewage and that other, more dangerous, organisms are present. These legislations are an important part in the fight against water pollution. They are useful in preventing Envioronmental catastrophes. The graph shows reported pollution incidents since 1989-1994. If stronger legislations existed, perhaps these events would never have occurred.
D.PARTHIBAN
LEGISLATION
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AND SCIENCE
UNEP was designed to be “the environmental conscience of the United Nations,” and, in an attempt to allay fears of the developing world, it became the first UN agency to be headquartered in a developing country, with offices in Nairobi, Kenya. In addition to attempting to achieve scientific consensus about major environmental issues, a major focus for UNEP has been the study of ways to encourage sustainable development increasing standards of living without destroying the environment. At the time of UNEP's creation in 1972, only 11 countries had environmental agencies. Ten years later that number had grown to 106, of which 70 were in developing countries.
ENVIRONMENTAL
Perhaps the biggest reason for developing a worldwide effort to monitor and restrict global pollution is the fact that most forms of pollution do not respect national boundaries. The first major international conference on environmental issues was held in Stockholm, Sweden, in 1972 and was sponsored by the United Nations (UN). This meeting, at which the United States took a leading role, was controversial because many developing countries were fearful that a focus on environmental protection was a means for the developed world to keep the undeveloped world in an economically subservient position. The most important outcome of the conference was the creation of the United Nations Environmental Program (UNEP).
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_____________________________ SOLID WASTES________________________________
Each household generates garbage or waste day in and day out. Items that we no longer need or do not have any further use for fall in the category of waste, and we tend to throw them away. There are different types of solid waste depending on their source. In today’s polluted
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AND SCIENCE
Since the beginning, humankind has been generating waste, be it the bones and other parts of animals they slaughter for their food or the wood they cut to make their carts. With the progress of civilization, the waste generated became of a more complex nature. At the end of the 19th century the industrial revolution saw the rise of the world of consumers. Not only did the air get more and more polluted but the earth itself became more polluted with the generation of nonbiodegradable solid waste. The increase in population and urbanization was also largely responsible for the increase in solid waste.
ENVIRONMENTAL
The sight of a dust bin overflowing and the stench rising from it, the all too familiar sights and smells of a crowded city. You look away from it and hold your nose as you cross it. Have you ever thought that you also have a role to play in the creation of this stench? That you can also play a role in the lessening of this smell and making this waste bin look a little more attractive if you follow proper methods of disposal of the waste generated in the house?
ENGINEERING
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What is solid waste?
D.PARTHIBAN
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world, learning the correct methods of handling the waste generated has become essential. Segregation is an important method of handling municipal solid waste. One of the important methods of managing and treating wastes is composting. As the cities are growing in size and in problems such as the generation of plastic waste, various municipal waste treatment and disposal methods are now being used to try and resolve these problems. One common sight in all cities is the rag picker who plays an important role in the segregation of this waste. Garbage generated in households can be recycled and reused to prevent creation of waste at source and reducing amount of waste thrown into the community dustbins.
3. Recycle. Use shopping bags made of cloth or jute, which can be used over and over again [will this come under recycle or reduce?].Segregate your waste to make sure that it is collected and taken for recycling. 4. Reduce. Reduce the generation of unnecessary waste, e.g. carry your own shopping bag when you go to the market and put all your purchases directly into it.
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2. Reuse. Do not throw away the soft drink cans or the bottles; cover them with homemade paper or paint on them and use them as pencil stands or small vases.
ENGINEERING
1. Refuse. Instead of buying new containers from the market, use the ones that are in the house. Refuse to buy new items though you may think they are prettier than the ones you already have.
D.PARTHIBAN
Four Rs (Refuse, Reuse, Recycle, and Reduce) to be followed for waste management
Household waste is generally classified as municipal waste, Industrial waste as hazardous waste, and Biomedical waste or hospital waste as infectious waste.
Municipal solid waste Municipal solid waste consists of household waste, construction and demolition debris, sanitation residue, and waste from streets. This garbage is generated mainly from residential and commercial complexes. With rising urbanization and change in lifestyle and food habits, the amount of municipal solid waste has been increasing rapidly and its composition changing. In 1947 cities
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SCIENCE
ENVIRONMENTAL
Solid waste can be classified into different types depending on their source:
AND
Types of solid waste
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and towns in India generated an estimated 6 million tones of solid waste; in 1997 it was about 48 million tones. More than 25% of the municipal solid waste is not collected at all; 70% of the Indian cities lack adequate capacity to transport it and there are no sanitary landfills to dispose of the waste. The existing landfills are neither well equipped nor well managed and are not lined properly to protect against contamination of soil and groundwater.
Garbage: the four broad categories Organic waste: kitchen waste, vegetables, flowers, leaves, fruits. Toxic waste: old medicines, paints, chemicals, bulbs, spray cans, fertilizer and pesticide containers, batteries, shoe polish. Recyclable: paper, glass, metals, plastics.
The type of litter we generate and the approximate time it takes to degenerate
Type of litter
Organic waste such as vegetable and fruit peels, leftover foodstuff, etc.
Paper
Approximate time it takes to degenerate the litter
a week or two.
10–30 days
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// ENGINEERING AND SCIENCE
There are different categories of waste generated, each take their own time to degenerate (as illustrated in the table below).
ENVIRONMENTAL
Over the last few years, the consumer market has grown rapidly leading to products being packed in cans, aluminium foils, plastics, and other such no biodegradable items that cause incalculable harm to the environment. In India, some municipal areas have banned the use of plastics and they seem to have achieved success. For example, today one will not see a single piece of plastic in the entire district of Ladakh where the local authorities imposed a ban on plastics in 1998. Other states should follow the example of this region and ban the use of items that cause harm to the environment. One positive note is that in many large cities, shops have begun packing items in reusable or biodegradable bags. Certain biodegradable items can also be composted and reused. In fact proper handling of the biodegradable waste will considerably lessen the burden of solid waste that each city has to tackle.
D.PARTHIBAN
Soiled: hospital waste such as cloth soiled with blood and other body fluids.
Cotton cloth
2–5 months
Wood
10–15 years
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1 year
Tin, aluminium, and other metal items such as cans
100–500 years
Plastic bags
One million years?
Glass bottles
undetermined
Hospital waste contaminated by chemicals used in hospitals is considered hazardous. These chemicals include formaldehyde and phenols, which are used as disinfectants, and mercury, which is used in thermometers or equipment that measure blood pressure. Most hospitals in India do not have proper disposal facilities for these hazardous wastes. In the industrial sector, the major generators of hazardous waste are the metal, chemical, paper, pesticide, dye, refining, and rubber goods industries.
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Household wastes that can be categorized as hazardous waste include old batteries, shoe polish, paint tins, old medicines, and medicine bottles.
ENGINEERING
Industrial and hospital waste is considered hazardous as they may contain toxic substances. Certain types of household waste are also hazardous. Hazardous wastes could be highly toxic to humans, animals, and plants; are corrosive, highly inflammable, or explosive; and react when exposed to certain things e.g. gases. India generates around 7 million tones of hazardous wastes every year, most of which is concentrated in four states: Andhra Pradesh, Bihar, Uttar Pradesh, and Tamil Nadu.
D.PARTHIBAN
Hazardous waste
Hospital waste Hospital waste is generated during the diagnosis, treatment, or immunization of human beings or animals or in research activities in these fields or in the production or testing of biological samples. It may include wastes like sharps, soiled waste, disposables, anatomical waste, cultures, discarded medicines, chemical wastes, etc. These are in the form of disposable syringes, swabs, bandages, body fluids, human excreta, etc. This waste is highly infectious and can be a serious threat to human health if not managed in a scientific and discriminate manner. It has been roughly estimated that of the 4 kg of waste generated in a hospital at least 1 kg would be infected.
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ENVIRONMENTAL
____________________________ HOSPITAL WASTES________________________
SCIENCE
AND
Direct exposure to chemicals in hazardous waste such as mercury and cyanide can be fatal.
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Plastics
Conventional plastics have been associated with reproductive problems in both wildlife and humans. Studies have shown a decline in human sperm count and quality, genital abnormalities and a rise in the incidence of breast cancer. Dioxin a highly carcinogenic and toxic by-product of the manufacturing process of plastics, is one of the chemicals believed to be passed on through breast milk to the nursing infant. Burning of plastics, especially PVC releases this dioxin and also furan into the atmosphere. Thus, conventional plastics, right from their manufacture to their disposal are a major problem to the environment.
Source of generation of waste plastics HOUSEHOLD
Carry bags Bottles Containers
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AND SCIENCE
But the good news is that along with a growth in the use, a country-wide network for collection of plastic waste through rag pickers, waste collectors and waste dealers and recycling enterprises has sprung all over the country over the last decade or so. More than 50% of the plastic waste generated in the country is recycled and used in the manufacture of various plastic products.
ENVIRONMENTAL
In India, the plastic industry is growing phenomenally. Plastics have use in all sectors of the economy – infrastructure, construction, agriculture, consumer goods, telecommunications, and packaging.
ENGINEERING
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Plastic with its exclusive qualities of being light yet strong and economical, has invaded every aspect of our day-to-day life. It has many advantages: it is durable, light, easy to mould, and can be adapted to different user requirements. Once hailed as a 'wonder material', plastic is now a serious worldwide environmental and health concern, essentially due to its non biodegradable nature.
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Trash bags
Plastics are so versatile in use that their impacts on the environment are extremely wide ranging. Careless disposal of plastic bags chokes drains, blocks the porosity of the soil and causes problems for groundwater recharge. Plastic disturbs the soil microbe activity, and once ingested, can kill animals. Plastic bags can also contaminate foodstuffs due to leaching of toxic dyes and transfer of pathogens. In fact, a major portion of the plastic bags i.e. approximately 60-80% of the plastic waste generated in India is collected and segregated to be recycled. The rest remains strewn on the ground, littered around in open drains, or in unmanaged garbage dumps. Though only a small percentage lies strewn it is this portion that is of concern as it causes extensive damage to the environment. The plastic industry in the developed world has realized the need of environmentally acceptable modes for recycling plastics wastes and has set out targets and missions. Prominent among such missions are the Plastic Waste Management Institute in Japan, the European Centre for Plastics in Environment, the Plastic Waste Management Task Force in Malaysia. Manufacturers, civic authorities, environmentalists and the public have begun to acknowledge the need for plastics to conform to certain guidelines/standards and code of conduct for its use. Designing eco-friendly, bio-degradable plastics are the need of the hour. Though partially biodegradable plastics have been developed and used, completely biodegradable plastics based on renewable starch rather than petrochemicals have only recently been developed and are in the early stages of commercialization.
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Mineral water bottles Plastic plates, glasses, spoons Plastic bags
ENGINEERING
AIR/RAIL TRAVEL
AND
Packaging items Mineral water bottles Plastic plates, glasses, spoons
SCIENCE
HOTEL AND CATERING
D.PARTHIBAN
Disposable syringes Glucose bottles Blood and urine bags Intravenous tubes Catheters Surgical gloves
ENVIRONMENTAL
HEALTH AND MEDICARE
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ENVIRONMENTAL
SCIENCE
AND
ENGINEERING
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_______________________ RECYCLING AND REUSE __________________________
D.PARTHIBAN
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Recycling and reuse
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Recycling involves the collection of used and discarded materials processing these materials and making them into new products. It reduces the amount of waste that is thrown into the community dustbins thereby making the environment cleaner and the air more fresh to breathe. Surveys carried out by Government and non-government agencies in the country have all recognized the importance of recycling wastes. However, the methodology for safe recycling of waste has not been standardized. Studies have revealed that 7 %-15% of the waste is recycled. If recycling is done in a proper manner, it will solve the problems of waste or garbage. At the community level, a large number of NGOs (Non Governmental Organizations) and private sector enterprises have taken an initiative in segregation and recycling of waste (EXNORA International in Chennai recycles a large part of the waste that is collected). It is being used for composting, making pellets to be used in gasifiers, etc. Plastics are sold to the factories that reuse them.
Old copies Old books Paper bags Newspapers Old greeting cards Cardboard box
Plastic
Containers Bottles Bags Sheets
Glass and ceramics
Bottles Plates Cup Bowls
Miscellaneous
Old cans Utensils Clothes Furniture
In your own homes you can contribute to waste reduction and the recycling and reuse of certain items. To cover you books you can use old calendars; old greeting cards can also be reused. Paper can also be made at home through a very simple process and you can paint on them.
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AND SCIENCE ENVIRONMENTAL
Most of the garbage generated in the household can be recycled and reused. Organic kitchen waste such as leftover foodstuff, vegetable peels, and spoilt or dried fruits and vegetables can be recycled by putting them in the compost pits that have been dug in the garden. Old newspapers, magazines and bottles can be resold.
ENGINEERING
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Paper
D.PARTHIBAN
The steps involved in the process prior to recycling include a) Collection of waste from doorsteps, commercial places, etc. b)Collection of waste from community dumps. c) Collection/picking up of waste from final disposal sites and some of the items can be recycled and reused
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ENVIRONMENTAL
SCIENCE
AND
The schematic diagram below depicts recycling of wastes
ENGINEERING
Fig :flow chart recycling plastic waste
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D.PARTHIBAN
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Management of Municipal Solid Waste
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Waste recycling has some significant advantages.
It leads to less utilization of raw materials. Reduces environmental impacts arising from waste treatment and disposal. Makes the surroundings cleaner and healthier. Saves on landfill space. Saves money. Reduces the amount of energy required to manufacture new products. In fact recycling can prevent the creation of waste at the source.
Treatment and disposal of municipal waste
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As cities are growing in size with a rise in the population, the amount of waste generated is increasing becoming unmanageable. The local corporations have adapted different methods for the disposal of waste – open dumps, landfills, sanitary landfills, and incineration plants. One of the important methods of waste treatment is composting.
D.PARTHIBAN
__________________ TREATMENT OF MUNICIPAL WASTES ______________________
Landfills are generally located in urban areas where a large amount of waste is generated and has to be dumped in a common place. Unlike an open dump, it is a pit that is dug in the ground. The garbage is dumped and the pit is covered thus preventing the breeding of flies and rats. At the end of each day, a layer of soil is scattered on top of it and some mechanism, usually an earth-moving equipment is used to compress the garbage, which now forms a cell. Thus, every day, garbage is dumped and becomes a cell. After the landfill is full, the area is covered with a thick layer of mud and the site can thereafter be developed as a parking lot or a park. Landfills have many problems. All types of waste is dumped in landfills and when water seeps through them it gets contaminated and in turn pollutes the surrounding area. This contamination of groundwater and soil through landfills is known as leaching.
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AND SCIENCE
Landfills
ENVIRONMENTAL
Open dumps refer to uncovered areas that are used to dump solid waste of all kinds. The waste is untreated, uncovered, and not segregated. It is the breeding ground for flies, rats, and other insects that spread disease. The rainwater run-off from these dumps contaminates nearby land and water thereby spreading disease. In some countries, open dumps are being phased out.
ENGINEERING
Open dumps
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Sanitary landfills An alternative to landfills which will solve the problem of leaching to some extent, is a sanitary landfill which is more hygienic and built in a methodical manner. These are lined with materials that are impermeable such as plastics and clay, and are also built over impermeable soil. Constructing sanitary landfills is very costly and they are have their own problems. Some authorities claim that often the plastic liner develops cracks as it reacts with various chemical solvents present in the waste. The rate of decomposition in sanitary landfills is also extremely variable. This can be due to the fact that less oxygen is available as the garbage is compressed very tightly. It has also been observed that some biodegradable materials do not decompose in a landfill. Another major problem is the development of methane gas, which occurs when little oxygen is present, i.e. during anaerobic decomposition. In some countries, the methane being produced from sanitary landfills is tapped and sold as fuel.
Modernization and progress has had its share of disadvantages and one of the main aspects of concern is the pollution it is causing to the earth – be it land, air, and water. With increase in the global population and the rising demand for food and other essentials, there has been a rise in the amount of waste being generated daily by each household. This waste is ultimately thrown into municipal waste collection centres from where it is collected by the area municipalities to be further thrown into the landfills and dumps. However, either due to resource crunch or inefficient infrastructure, not all of this waste gets collected and transported to the final dumpsites. If at this stage the management and disposal is improperly done, it can cause serious impacts on health and problems to the surrounding environment. Waste that is not properly managed, especially excreta and other liquid and solid waste
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// ENVIRONMENTAL
Health impacts of solid waste
SCIENCE
AND
Burning garbage is not a clean process as it produces tones of toxic ash and pollutes the air and water. A large amount of the waste that is burnt here can be recovered and recycled. In fact, at present, incineration is kept as the last resort and is used mainly for treating the infectious waste.
ENGINEERING
This process of burning waste in large furnaces is known as incineration. In these plants the recyclable material is segregated and the rest of the material is burnt. At the end of the process all that is left behind is ash. During the process some of the ash floats out with the hot air. This is called fly ash. Both the fly ash and the ash that is left in the furnace after burning have high concentrations of dangerous toxins such as dioxins and heavy metals. Disposing of this ash is a problem. The ash that is buried at the landfills leaches the area and cause severe contamination.
D.PARTHIBAN
Incineration plants
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from households and the community, are a serious health hazard and lead to the spread of infectious diseases. Unattended waste lying around attracts flies, rats, and other creatures that in turn spread disease. Normally it is the wet waste that decomposes and releases a bad odour. This leads to unhygienic conditions and thereby to a rise in the health problems. The plague outbreak in Surat is a good example of a city suffering due to the callous attitude of the local body in maintaining cleanliness in the city. Plastic waste is another cause for ill health. Thus excessive solid waste that is generated should be controlled by taking certain preventive measures. Impacts of solid waste on health
DISPOSAL OF HOSPITAL AND OTHER MEDICAL WASTE requires special attention since this can create major health hazards. This waste generated from the hospitals, health care centres, medical laboratories, and research centres such as discarded syringe needles, bandages, swabs, plasters, and other types of infectious waste are often disposed with the regular non-infectious waste. WASTE TREATMENT AND DISPOSAL SITES can also create health hazards for the neighbourhood. Improperly operated incineration plants cause air pollution and improperly managed and designed landfills attract all types of insects and rodents that spread disease. Ideally these sites should be located at a safe distance from all human settlement. Landfill sites should be well lined and walled to ensure that there is no leakage into the nearby ground water sources.
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// ENGINEERING AND SCIENCE
EXPOSURE TO HAZARDOUS WASTE can affect human health, children being more vulnerable to these pollutants. In fact, direct exposure can lead to diseases through chemical exposure as the release of chemical waste into the environment leads to chemical poisoning. Many studies have been carried out in various parts of the world to establish a connection between health and hazardous waste. WASTE FROM AGRICULTURE AND INDUSTRIES can also cause serious health risks. Other than this, co-disposal of industrial hazardous waste with municipal waste can expose people to chemical and radioactive hazards. Uncollected solid waste can also obstruct storm water runoff, resulting in the forming of stagnant water bodies that become the breeding ground of disease. Waste dumped near a water source also causes contamination of the water body or the ground water source. Direct dumping of untreated waste in rivers, seas, and lakes results in the accumulation of toxic substances in the food chain through the plants and animals that feed on it.
ENVIRONMENTAL
In particular, ORGANIC DOMESTIC WASTE poses a serious threat, since they ferment, creating conditions favorable to the survival and growth of microbial pathogens. Direct handling of solid waste can result in various types of infectious and chronic diseases with the waste workers and the rag pickers being the most vulnerable.
D.PARTHIBAN
The group at risk from the unscientific disposal of solid waste include – the population in areas where there is no proper waste disposal method, especially the pre-school children; waste workers; and workers in facilities producing toxic and infectious material. Other high-risk groups include population living close to a waste dump and those, whose water supply has become contaminated either due to waste dumping or leakage from landfill sites. Uncollected solid waste also increases risk of injury, and infection.
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Occupational hazards associated with waste handling
Certain chemicals if released untreated, e.g. cyanides, mercury, and polychlorinated biphenyls are highly toxic and exposure can lead to disease or death. Some studies have detected excesses of cancer in residents exposed to hazardous waste. Many studies have been carried out in various parts of the world to establish a connection between health and hazardous waste.
The role of plastics The unhygienic use and disposal sposal of plastics and its effects on human health has become a matter of concern. Coloured plastics are harmful as their pigment contains heavy metals that are highly toxic. Some of the harmful metals found in plastics are copper, lead, chromium, cobalt, selenium, and cadmium. In most industrialized countries, colour plastics have been legally banned. In India, the Government of Himachal Pradesh has banned the use of plastics and so has Ladakh district. Other states should emulate their example.
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// ENGINEERING
Diseases
AND
RECYCLING too carries health risks if proper precautions are not taken. Workers working with waste containing chemical and metals may experience toxic exposure. Disposal of health-care care wastes require special attention since it can create major health hazards, such as Hepatitis B and C, through wounds caused by discarded syringes. Rag pickers and others who are involved in scavenging in the waste dumps for items that can be recycled, recy may sustain injuries and come into direct contact with these infectious items.
SCIENCE
Source - Adapted from UNEP report, 1996
ENVIRONMENTAL
Accidents Bone and muscle disorders resulting from the handling of heavy containers. Infecting wounds resulting from contact with sharp objects. Poisoning and chemical burns resulting from contact with small amounts of hazardous chemical waste mixed with general waste. Burns and other injuries resulting from occupational accidents at waste disposal sites or from methane ethane gas explosion at landfill sites.
D.PARTHIBAN
Infections Skin and blood infections resulting from direct contact with waste, and from infected wounds. Eye and respiratory infections resulting from exposure to infected dust, especially during landfill operations. Different diseases that results from the bites of animals feeding on the waste. Intestinal infections that are transmitted by flies feeding on the waste. Chronic diseases Incineration ncineration operators are at risk of chronic respiratory diseases, including cancers resulting from exposure to dust and hazardous compounds.
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Preventive measures Proper methods of waste disposal have to be undertaken to ensure that it does not affect the environment around the area or cause health hazards to the people living there.
ENVIRONMENTAL
SCIENCE
AND
ENGINEERING
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D.PARTHIBAN
At the household-level proper segregation of waste has to be done and it should be ensured that all organic matter is kept aside for composting, which is undoubtedly the best method for the correct disposal of this segment of the waste. In fact, the organic part of the waste that is generated decomposes more easily, attracts insects and causes disease. Organic waste can be composted and then used as a fertilizer.
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Smog
The term smog was first used in 1905 by Dr H A Des Voeux to describe the conditions of fog that had soot or smoke in it.
The industrial revolution in the 19th century saw the beginning of air pollution in
Europe on a large scale and the presence of smog mainly in Britain. The industries and the households relied heavily on coal for heating and cooking. Due to the burning of coal for heat during the winter months, emissions of smoke and sulphur dioxide were much greater in urban areas than they were during the summer months. Smoke particles trapped in the fog gave it a yellow/black colour and this smog often settled over cities for many days.
The effects of smog on human health were evident, particularly when smog persisted for several days. Many people suffered respiratory problems and increased deaths were recorded, notably those relating to bronchial causes. LONDON SMOG:
A haze of dense harmful smog would often cover the city of London. The first smogrelated deaths were recorded in London in 1873, when it killed 500 people. In 1880, the toll was 2000. London had one of its worst experiences with smog in December 1892. It lasted for three days and resulted in about 1000 deaths. London became quite notorious for its smog. Despite gradual improvements in air quality during the 20th century, Another major smog occurred in London in December 1952. The Great London Smog lasted for five days and resulted in about 4000 more deaths than usual.Relatively little was done to control any type of pollution or to promote environmental protection until
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ENGINEERING
AND
SCIENCE
ENVIRONMENTAL
water vapour and dust. A large part of the gases that form smog is produced when fuels are burnt. Smog forms when heat and sunlight react with these gases and fine particles in the air. Smog can affect outlying suburbs and rural areas as well as big cities. Its occurrences are often linked to heavy traffic, high temperatures, and calm winds. During the winter, wind speeds are low and cause the smoke and fog to stagnate; hence pollution levels can increase near ground level. This keeps the pollution close to the ground, right where people are breathing. It hampers visibility and harms the environment. Heavy smog is greatly decreases ultraviolet radiation. In fact, in the early part of the 20th century, heavy smog in some parts of Europe resulted in a decrease in the production of natural vitamin D leading to a rise in the cases of rickets. Smog causes a misty haze similar to fog, but very different in composition. In fact the word smog has been coined from a combination of the words fog and smoke. Smog refers to hazy air that causes difficult breathing conditions. The most harmful components of smog are ground-level ozone and fine airborne particles. Ground-level ozone forms when pollutants released from gasoline and dieselpowered vehicles and oil-based solvents react with heat and sunlight. It is harmful to humans, animals, and plants.
D.PARTHIBAN
Smog is a combination of various gases with
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the middle of the 20th century. Today, smoke and sulphur dioxide pollution in cities is much lower than in the past, as a result of legislation to control pollution emissions and cleaner emission technology.
________________________ NOISE POLLUTION ___________________________
Effects of Noise Pollution: → → →
→
Noise can disturb out work, rest, sleep and communication. It can damage our hearing and evoke other psychological, physiological and possibly pathological reactions. However, because of the complexity, variability and the interaction of noise with other environmental factors, the adverse health effects of noise do not lend themselves to a straightforward analysis. The strength of sound level and its subjective feeling / effects on human beings are summarized below.
VARIOUS SOUND LEVELS AND ITS EFFECTS ON HUMAN BEINGS
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AND
The various sources of noises are associated with urban development; road-air and rail transport; Industrial noise. In addition to the indoor sources like air conditioners, air resources, fan, radio, TV and other home and officer appliances can be included. In our country, indiscriminate use of loud speakers, generator sets and firecrackers has given new dimensions to the noise pollution problem. The physical properties and perception of sound or noise are expressed and measured in different concepts and units. The commonly used parameter for noise is the sound level in decibels (dBA). Human ears are sensitive in the frequency range of 20Hz to 20 kHz.
SCIENCE
ENVIRONMENTAL
Noise Pollution can be defied as unwanted or offensive sounds that unreasonably intrude in to our daily activities. Sound, which pleases listener’s music and that, which causes pain and annoyance is noise. At times, what is music for it can be noise for others. Noise prevention and control is important as noise affects our nearing, ability to communicate and behavior undoubtedly lesser noise can make the environment friendlier and life became pleasant.
D.PARTHIBAN
What is Noise Pollution?
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Sound Level dBA
Subjective Feeling of Human Beings
Rockets and missiles, heavy explosives
150-160
Unbearable
Jet Planes and cannons, explosives
140
Unbearable
Aircraft Propeller and Machine Guns
130
Unbearable
Diesel, steam engine and ball mills, crackers
120
Unbearable
Electric saws and looms, heavy trucks
110
Unbearable
Sound Level dBA
Subjective Feeling of Human Beings
Lorries, highway vehicles and very busy streets
90-100
Very noisy
Commercial place, air conditioners, loud voice and busy streets
70-80
Noisy
Office complex, average loudness of voices
60
Noisy
Ordinary room
50
Quiet
Above 150 dBA may cause severe damage to the whole body such as loss of hearing of both ears, dizziness, nausea, disturbance of speech, confusion or psychosis.
Above 90dBA may cause headache, dizziness, tinnitus, insomnia, deafness, heart disease, blood hypertension, gastric ulcers, neurosis, temporary hearing threshold shift.
Effects on Human Beings
AND
50-90 dBA may cause various degrees of effects in sleeping, studying, working and talking
ENGINEERING
//
Sound Source
Effects on Human Beings
D.PARTHIBAN
Sound Source
145
SCIENCE
Sense of noisy feeling
Silent night, library
30-40
Very quiet
Hospital, bedroom at night, church
20-30
Very quiet
Sound proof room, broadcasting studio
10-20
Very quiet
Serene feeling
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ENVIRONMENTAL
Pleasant feeling
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Lower limit of hearing
0
Very quiet
146
Threshold of hearing
Standards For Noise Pollution:
Max. Noise Level in dBAq*
(6 AM to 10PM)
(10PM to 6AM)
Industrial Area
75
70
Commercial Area
65
55
Residential Area
55
45
Silence Zone$
50
40
Effects of the bad noise pollution on life loads to a standard Environmental protection Act – 1989, for ambient our quality standards with respective noise. These reveals with noise standard for automobiles generate sets, as fireworks etc. Noise standards for Motor Vehicle Rules, 1989. Noise exposure limits for work zone area have been prescribed in the Model Rules framed under the Factories Act, 1948.
AND
Ambient air quality standards with respect to noise:
//
Night Time
ENGINEERING
Day Time
D.PARTHIBAN
Category of Area / Zone
Silence zone is an area comprising not less than 100 meters around hospitals, educational institutions, courts, religious places or any other area which is declared as such by the competent authority. Noise standards for generator sets, fire crackers, house-hold appliances and construction equipment:
Category
Gensets, run with petrol or kerosene
Max. Noise Level, dBA
Effective From
90
1 Sep. 2002
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ENVIRONMENTAL
$
SCIENCE
* Leq is time weighted coverage of the sound level over 24 hours.
Page:
Gensets run with diesel (upto 1000 KVA) Firecrackers
86
1 Sep. 2003
75
1 July 2003
125
1999
147
Noise Limits in Factories: No worker in his work-place should be exposed to a noise level of 90 dBA for more than 8 h. Though the changes appear to be small by figure, they will have a great impact when calculated in terms of noise production. A number of factors contribute to problems of high noise levels, including.
2. Air Traffic: The extend of aircraft noise impact depends on the type of aircraft flown, the number of flights and flight paths. The increase in number of flights, an important factor is overall noise levels, the led to an increase in general noise levels associated with air traffic. 3. Rail Traffic: The two main sources of noise and vibration relating to the operation of the rail network is 1. 2.
The operation of trains and the maintenance Construction of rail infrastructure.
The level of noise associated with rail traffic is related to the type of engine, the speed of the train tack type and condition. Electric train generates less noise pollution and diesel.Rail noise can be considerable bar generally affects a far smaller group of the population than road as it is generally confined to residents living along rail lines is urban areas. Neighborhood & Domestic Noise:
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D.PARTHIBAN //
Road traffic noise is one of the most widespread and growing environmental problems in urban area. The impact of road traffic noise on the community depends an various factors such as road location and design, land use planning measures, building design, Vehicle standards and deriver behavior. Motor vehicle ownership in India has increased substantially over the last 30 years and general levels of road traffic noise throughout India have increased through out the period.
ENGINEERING
1. Road Traffic:
AND
Major Noise Sources:
SCIENCE
2.
Increasing population, particularly where it leads to increasing urbanization and urban consolidation, activities associated with urban living generally lead to increased noise level. Increasing volumes of road, rail and air traffic.
ENVIRONMENTAL
1.
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Other significant source of noise annoyance is barking dogs, car alarms building construction and household noise.
__________________________ THERMAL POLLUTION ____________________________
ENVIRONMENT POLLUTION DUE TO THERMAL POWER PLANTS -CAUSES, EFFECTS & REMEDIES
TABLE : CHEMICAL COMPOSITION OF I NDIAN COALS
Material Moisture Hydrogen Carbon Sulphur Nitrogen Oxygen Ash
Singareni 10.00 2.50 38.00 0.50 1.50 7.50 40.00
Kampte 10.00 3.40 45.70 0.40 0.70 11.80 28.00
Korba 5.50 5.50 37.30 0.30 0.80 7.20 46.50
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// ENGINEERING AND
Main pollutants from thermal plant: The burning of fuels (coal, oil & gas) cause the emission of following pollutants (which are carried by flue gas to the atmosphere): 1.Flyash 2. (a) Carbon monoxide (CO), (b) Carbon dioxide (CO2), (c) Sulfur dioxide (SO2), (d) Nitrogen dioxide (NO2), (e) Nitric oxide (NO) and 3.Smoke and dust. The chemical composition of Indian coal is given in Table 1.
SCIENCE
Steam or Thermal Power station: In the thermal power station, the steam is produced in the boiler, using the heat released by the combustion of coal, oil or natural gas. The steam is used to rotate the steam turbine (impulse/ reaction). The steam turbine drives the alternator, which converts mechanical energy into electrical energy. The schematic arrangements of thermal power station are shown in fig.1(given in page 2).
ENVIRONMENTAL
Introduction: Energy is the basic necessity for the economic development of a country. In fact the standard of living is related to the energy consumed. Energy exists in different forms. Also, it can be converted from one form to another form. Electrical energy is superior to all other forms of energy due to its advantages such as: easy conversion from one form to another, easy control, cleanliness, high transmission efficiency etc. The electrical energy is produced in power plants or generating stations. The conventional power plants are: 1. Steam or Thermal Power station, 2. Hydro-electric Power station, 3. Nuclear Power station and 4.Diesel Power station.
D.PARTHIBAN
This handout briefly presents the environmental pollution caused due to thermal power plants. The main pollutants, their effects on the air, water & land and the remedial steps to be taken to alleviate the health hazard are also presented. More emphasize is given on fly ash collection and its effective utilization, as the quantity of fly ash produced in coal fired thermal power plant is very high.
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Effects of pollutants: The typical values of Maximum Permissible Concentrations (MPC) of some of the harmful substances in air are presented in the table 2. If the levels of these pollutants exceed the MPC, they pollute the air, water and to some extent the land. Table 2. Maximum permissible concentrations of pollutants
Table 3. Chemical composition of coal ash from Indian coals
Material
Singareni
Pench west
Fe2 O3 SiO2 Al2 O3 Ca O Mg O Ti O2 P 2 O5
3.20 61.01 31.06 0.86 0.13 2.24 0.10
7.90 62.70 24.80 0.88 0.62 1.48 0.11
Kamite Seam 12.50 59.00 23.00 1.10 0.50 1.40 0.17
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// ENGINEERING
India has a coal reserve of 200 billion tons and the current annual production of 300 million tons. The ash content of coal used at the thermal power plants range from 35% to 55%. Existing thermal power plants in the country, which currently produce about 50 million tons of fly ash per annum needing 40,000 acres of precious land for disposal of fly ash during their life span of 30 years. The annual expenditure on transportation alone to dump the fly ash is around Rs.30 crores. While only very small percentage (3 to 5%) of fly ash generated is being used for gainful applications, in India, the corresponding figures for other countries vary from 10%-75%. As a thumb rule, for every MW of installed capacity, approximately one acre of land is required for disposal of the ash generated, the material accumulating to a height of 8 to 10 m. The chemical compositions of coal ash from Indian coals are presented in Table 3.
AND
Fly ash Fly ash is a finely divided residue resulting from the combustion of pulverized bituminous coal or lignite in a thermal power plant. It is generally gray in color, abrasive, acidic, refractory in nature and has a fineness of 4000 to 8000 sq.cm per gram The ash particles ranging in size from 120 to less than 5 microns in equivalent diameters which are carried away with flue gases is called fly ash.
D.PARTHIBAN
Highest (single day) 0.15 0.5 3.00 0.085 0.008
SCIENCE
Average (daily) 0.05 0.15 1.00 0.085 0.008
ENVIRONMENTAL
Pollutant Soot (Fly ash) Non toxic dust CO Nitrogen dioxide Hydrogen sulphide
Page: Na2 O K2 O SO3
0.16 0.79 0.45
0.16 0.90 0.45
150
0.14 0.88 1.31
Eletrostatic precipitator The ESP consists of casing, hoppers, bus distributor screen, two electrodes (one in the form of thin wire called discharge or emitting electrode and the other is in the form of plates called collecting electrodes), rapping mechanism, insulator housing HVDC and control system. The emitting electrodes are placed in the midway between two plates and are connected to negative polarity of the source and are grounded. The high electric field in the vicinity of emitting electrodes creates corona discharge ionizing the gas molecules. The dust particles entrained in the gas acquire negative charge and experience a force, which drives them towards the collecting electrodes where they get deposited. A process called rapping dislodges the collected material.
Hazard due to Fly ash Fly ash is a harmful environment pollutant being light, it gets airborne very fast and pollutes atmosphere. Long inhalation causes, silicoses, fibrosis of lungs, bronchitis and pneumonitis etc. Fly ash corrodes structural surfaces and its deposition affects horticulture. Slurry disposal lagoons/ settling tanks become source of mosquitoes and bacteria. In addition it holds the potential to contaminate the underground water resources with traces of toxic metals present in it. Fly ash disposal in sea/river disrupts aquatic life cycles. Thus, time has come to promote and support fly ash utilization effectively.
Hazard due to Toxic substances: A 500 MW coal fired plant, having no pollution control equipment, would emit nearly 100 tons of SO2, 20 tons of NO2 and 1000 tons of ash daily.
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// ENGINEERING AND
During ESP operation, dust will be collected on the electrodes and corona will gradually be suppressed as the dust layer grows. It is necessary to rap the electrode periodically by employing tumbling hammers, which are mounted on the horizontal shaft of the motor. While shaft is rotating the shock energy generated by the hammers are transmitted to the electrodes, thereby the dust is made to fall into the ESP hoppers.
SCIENCE
Rapping system
ENVIRONMENTAL
The general block diagram is shownFig.2. The input 415 V is applied to the thyristor controller. The output from controller is fed into the primary side of the high voltage transformer through a current limiting reactor. The a c output from the secondary of the h v transformer is converted into d.c by using a rectifier. The high voltage d.c. voltage applied to the respective electrodes of ESP. The heating element provided on the ESP ensure free flow of ash from the hoppers by keeping the temperature of ash above dew point.
D.PARTHIBAN
Electrical operation
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151
The CO is injurious to human health as it combines with hemoglobin in the red blood corpuscles and interferes with their normal function of supplying oxygen to the blood tissues. Carbon dioxide (CO2) can change the fertile land into a non- fertile land. Sulphur dioxide (SO2) (which is due to the combustion of bituminous coal and residue oil) deteriorates the surface of leaves in the vegetables. It also causes yellowing of leaf, transient reduction in live plant biomass and long term reduction in crop growth and yield. It also increases the corrosion rate of steel.
TABLE: STATISTICS SHOWING THE FLY ASH UTILIZATION IN DIFFERENT COUNTRI ES
Country
Total fly ash production in Million Tons
% Utilization
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// ENGINEERING AND
Hazards due to water discharge When a river is available near by, the water withdrawal and discharge back by the power plants can affect the aquatic life due to chemical contamination, thermal effect, entrainment, entrapment, oxygen sag etc.
SCIENCE
Hazards due to cooling tower Cooling towers are huge hyperbolic structures measuring more than 100m in height, which use natural air draft (created by tower’s height and shape) for cooling the water. When the surrounding air cannot absorb moisture, some droplets of circulating water escape from the tower. The droplets called drift carry with them salts and chemicals which can damage vegetation, cause weathering and corrosion of metals and may even change soil properties. The cooling tower water when added to atmosphere may condense and form fog at ground level. The wind conditions may cause concentration of dense fog over a small area decreasing the visibility in that area. Cooling tower can even produce visible plumes/clouds.
ENVIRONMENTAL
Acid rain is another menace caused by thermal power plants. The three main constituents of flue gases which mainly affect acidity of rains are SO2, NO and NO2. In the atmosphere, sulphur dioxide gets converted into sulphuric acid (H2 SO4) and the nitrogen oxides get converted into nitric acid (HNO3). During the rainy seasons, the acid formed in the atmosphere falls on the ground in the form of rain called acid rain. The acid rain increases the acidity of well water, lake water and the water flowing to the rivers. In general, SO2 contributes 60% of acidity, where as nitrogen oxides contribute 35% acidity. The further detrimental effect of acid rains is the reduction of ground fertility and crop yield.
D.PARTHIBAN
Nitrogen dioxide (NO2) & nitric oxide (NO) produce sharp irritating effect. They also cause respiratory diseases. When NO2 reacts with water, aquatic organisms are damaged. Vegetation damage due to high concentration of NO2 in atmosphere includes leaf damage and decreased plant yield
Page: Australia Canada China Denmark France Hungary Japan Poland U.K. U.S.A. India
5.75 3.15 35 1.1 4.6 4 3.7 17 10 70 60
152
10 40 20 75 65 25 13 40 60 17 5
E-WASTE AND THEIR PROBLEM
ENVIRONMENTAL
SCIENCE
AND
Electronic scrap items which poses problem to the environment includes monitors, televisions, printers, keyboards, mice, scanners, fax machines, telephone handsets, VCRs, CPUs, cellular phones without batteries and other small consumer electronics
//
__________________ E-WASTES ______________________
ENGINEERING
Utilization of fly ash in building industry: In building industry, fly ash is being utilized in the manufacture of lime fly ash bricks, building blocks, clay bricks, cement, Fal-G-concrete blocks.
D.PARTHIBAN
Hence, there is a need to enhance the effective utilization of the large quantity of fly ash being generated from the thermal power plants. Some of the applications of fly ash are listed below.
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ENVIRONMENTAL
SCIENCE
AND
ENGINEERING
//
D.PARTHIBAN
Page:
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ENVIRONMENTAL
SCIENCE
AND
ENGINEERING
//
D.PARTHIBAN
Page:
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155
ENVIRONMENTAL
SCIENCE
AND
ENGINEERING
//
D.PARTHIBAN
Page:
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Solder in printed circuit boards, glass panels and gaskets in computer monitors
Lead (PB)
Chip resistors semiconductors
and
Cadmium (CD)
Relays and switches, printed circuit boards
Mercury (Hg)
Damage to central and peripheral nervous systems, blood systems and kidney damage. Affects brain development of children. Toxic irreversible effects on human health. Accumulates in kidney and liver. Causes neural damage. Teratogenic. Chronic damage to the brain. Respiratory and skin
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AND
Health effects
SCIENCE
Constituent
ENVIRONMENTAL
Source of e-wastes
ENGINEERING
//
D.PARTHIBAN
Page:
Page:
disorders due bioaccumulation fishes.
Hexavalent chromium (Cr) VI
Front panel of CRTs
Cabling and computer housing
Motherboard
Asthmatic bronchitis. DNA damage.
Short term exposure causes: Muscle weakness; Damage to heart, liver and spleen.
Plastic housing of electronic equipments and circuit boards.
to in
ENVIRONMENTAL
SCIENCE
AND
ENGINEERING
//
Carcinogenic (lung cancer) Inhalation of fumes and dust. Causes chronic beryllium disease or beryllicosis. Skin diseases such as warts
D.PARTHIBAN
Corrosion protection of untreated and galvanized steel plates, decorator or hardner for steel housings
157
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SCIENCE
AND
ENGINEERING
//
D.PARTHIBAN
ۼ܃۷ ܂െ ǣ ۽܁۱۷ۺۯ ۽܁۱۷ۺۯ۷܃܁܁۳ۼۯ܁۲܂۶۳۳܄ۼ۷ۻۼ۽܀۳܂ۼ
RAIN WATER HARVESTING CLIMATE CHANGE GLOBAL WARMING OZONE LAYER DEPLETION WATER POLLUTION PREVENTION AND CONTROL ACT AIR POLLUTION PREVENTION AND CONTROL ACT WILD LIFE PROTECTION ACT
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ENVIRONMENTAL
CHAPTER-IV PROVIDES INFORMATION ON:
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UNIT – 4 SOCIAL ISSUES AND THE ENVIRONMENT
Sustainable D Development – Economy, Environment & Society CONCEPTS OF SUSTAINABLE DEVELOPMENT
Goodland and Ledec define sustainable development as, ‘a pattern of social and structural economic transformation (i.e. development) which op optimises timises the economic and other societal benefits available in the present without jeopardising the likely potential for similar benefits in the future.’
Barbier and Markandya (1990) emphasise the processes rather than the aims: ‘in general, the wider objective ctive of sustainable development is to find the optimal level of interaction among three systems – the biological and resource system, the economic system and the social system, through a dynamic and adaptive process of trade trade-offs.’
The concept of sustainable ble development is a process of consensus consensus-based based decision making in which the impact of economic activities (the economy) the environment (ecosystems), and the health (well(well being) of society are integrated and balanced, without compromising the ability of present p and future generations to meet their needs, so that all three - the economy, the environment, and the health of society - can be sustained into the future
ENVIRONMENTAL
SCIENCE
AND
Pictorial Descriptions
//
Sustainable development is said to ‘meet the needs of the present without compromising the ability of future generations to meet their own needs.’(United Nations World Commission on Environment and Development, Brundtland Report, 1987).
ENGINEERING
D.PARTHIBAN
Development Vs Environment
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Concepts of sustainable development
Role of Government
Provide a broad range of opportunities for learning about sustainable development concepts and practices. Reform regulations and develop incentives to encourage practices that have net environmental, economic and community benefits over the long run. Provide incentives for business interested in developing and adopting sustainable practices and technologies. Examine the role of taxes and subsidies in encouraging sustainable development. Establish new institutions / organizations outside of Government to aid in facilitating sustainable development. Government should set an example of sustainability in own operations and functions.
D.PARTHIBAN
//
Use renewable resources at a rate that can be maintained over time. Gradually reduce reliance on and limit the release of toxic substances that do not readily break down in nature Use all resources as efficiently and fairly as possible so that present and future generations can meet their needs. Reflect the inter dependence of social, economic and environmental conditions. Preserve the integrity of ecological process and biological diversity. Use land, air and water in ways that meet people’s diverse needs and preserve land’s ability to meet future needs. Reduce the amount of materials and energy used to produce goods and services. Promote the use of recyclable / reusable products and services.
ENGINEERING
Role of International Organizations
Cooperation and coordination of international and regional organizations. Governments and non-governmental organizations should develop programmes for children collaborating with UNICEF.
Agenda 21 The concept of sustainable development was introduced in the 1992 Earth Summit held at Rio. In the conference, a legal document/blue print for sustainable development called Agenda 21 was put forth. The
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SCIENCE
Promote environmentally sound business Look for opportunities to turn waste streams into profit streams. Support the development of renewable energy resources. Educate others about the necessity and essentials of sustainable development. Join in NGOs / Institutions involved in the activity and contribute your skills towards the development of nation.
ENVIRONMENTAL
AND
Role of citizens
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table of contents of Agenda 21 describes the nature of issues and topics related to sustainable development.
Chapter 1 Preamble
Section I. Social and Economic Dimensions
Chapter Chapter Chapter Chapter Chapter Chapter Chapter
2 3 4 5 6 7 8
International Cooperation for Sustainable Development Combating Poverty Changing Consumption Patterns Demographic Dynamics & Sustainability Human Health Human Settlements Decision Making
Chapter Chapter Chapter Chapter Chapter Chapter Chapter Chapter Chapter Chapter
23 24 25 26 27 28 29 30 31 32
Preamble Major Groups Women Children & Youth Indigenous People Non-Governmental Organizations Local Authorities Trade Unions Business & Industry Scientific & Technological Community Role of Farmers
Section IV. Means of Implementation
Chapter 33 Financial Resources Chapter 34 Technology Transfer Chapter 35 Science for Sustainable Development
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// ENGINEERING
Section III. Strengthening the Role of Major Groups
AND
9 Protection of the Atmosphere 10 Land Resources 11 Deforestation 12 Desertification & Drought 13 Sustainable Mountain Development 14 Sustainable Agriculture & Rural Development 15 Conservation of Biodiversity 16 Biotechnology 17 Protection of the Oceans 18 Freshwater Resources 19 Toxic Chemicals - Management 20 Hazardous Wastes - Management 21 Solid Wastes - Management 22 Radioactive Wastes - Management
SCIENCE
Chapter Chapter Chapter Chapter Chapter Chapter Chapter Chapter Chapter Chapter Chapter Chapter Chapter Chapter
ENVIRONMENTAL
D.PARTHIBAN
Section II. Conservation and Management of Resources for Development
Page:
Chapter Chapter Chapter Chapter Chapter
36 37 38 39 40
162
Education, Public Awareness & Training Capacity Building in Developing Countries International Institutions International Legal Instruments Information for Decision-making
Sustainable Development – Indian Response India presented its perspective on sustainable development before the World Summit for Sustainable Development (WSSD) in 2002 as detailed study “Empowering People for Sustainable Development” (EPSD). It was brought out by the Ministry of Environment and Forests.
EPSD introduces the essential framework for sustainable development in India: democratic continuity, devolution of power, independent judiciary, and civilian control of the armed forces, independent media, transparency and people's participation. It follows multidimensional, sectoral and cross-sectoral approaches. The EPSD has four main objectives Combating poverty Empowering people Using core competence in science and technology Setting environmental standards
Water Harvesting-Concepts &Methods INTRODUCTION Water is nectar of life and life cannot sustain without it. Ever increasing demands of water for domestic, irrigation as well as industrial sectors have created water crisis worldwide. Ground water is the only
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AND
Reduction of poverty ratio by 5 percentage points by 2007 and by 15 percentage points by 2012 All children in school by 2003; all children to complete 5 Years in school by 2007 Reduction in gender gaps in literacy and wage rates by at least 50 % by 2007 Reduction in population growth between 2001 and 2011 to 16.2 % Increase in literacy rate to 75 % by 2007 Reduction of Infant Mortality Rate (IMR) to 45 per 1000 live births by 2007 and to 28 by 2012 Reduction of Maternal Mortality Rate (MMR) to 2 per 1000 live births by 2007 and to 1 by 2012 Increase in forest cover to 25 % by 2007 and 33 % by 2012 All villages to have sustained access to potable drinking water by 2007 Cleaning of major polluted rivers by 2007 and other notified stretches by 2012
SCIENCE
ENVIRONMENTAL
The Indian Government has set the following targets for sustainable development in the 10th Five year plan.
ENGINEERING
//
D.PARTHIBAN
The Indian Government did not feel the need for a separate specific strategy for sustainable development. The Five Year Plans provide medium-term strategies for overall development. However, after the WSSD, the Indian government initiated a process of preparing and implementing a national strategy for sustainable development by 2005.
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dependable source of water. Inferior quality of groundwater with high salinity, fluoride and nitrate contents further limits the availability of fresh water assets. Depleting groundwater resources, water logging hazards, deep water levels, higher degree of salinity, high fluoride and nitrate concentration, industrial pollution etc. are the main ground water related areas of concern which needs appropriate attention of management for Rain Water Harvesting & Artificial Recharging.
WHY RAIN WATER HARVESTING? Ground water plays a critical role in the urban environment. It has a significant contribution in municipal, industrial and domestic water supply. Urbanization strongly affects ground water recharge flow and quality thereby creating serious impact on urban infrastructure that may lead to socio – economic and environmental degradation of the area. As urban dwellings go on increasing shrinkage of open land leads to continuous decline in ground water levels in many areas.
To arrest sea water ingress. To improve the water quality in aquifers. To improve the vegetation cover. To raise the water levels in wells & bore wells that are drying up. To reduce power consumption.
ENVIRONMENTAL
SCIENCE
AND
//
and recharging of ground water has diminished. Over – exploitation of ground water resources has resulted in declined in water levels in most part of the country. To enhance availability of ground water at specific place and time.
ENGINEERING
Surface water is adequate to meet our demand and we have to depend on ground water. Due to rapid urbanization infiltration of rain water into the sub – soil has decreased drastically
D.PARTHIBAN
Rain water harvesting is essential because :-
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164
WHAT IS RAIN WATER HARVESTING : An old technology is gaining popularity in a new way. Rain water harvesting is enjoying a renaissance of sorts in the world, but it traces its history to biblical times. Extensive rain water harvesting apparatus existed 4000 years ago in the Palestine and Greece. In ancient Rome, residences were built with individual cisterns and paved courtyards to capture rain water to augment water from city's aqueducts. As early as the third
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AND
An ideal solution of water problem in areas having inadequate water resources. The ground water level will rise. Mitigates the effect of drought & achieves drought proofing. Reduces the runoff which chokes the storm water drains. Flooding of roads is reduced. Quality of water improves. Soil erosion will be reduced. Saving ground water – one meter of rise in water level saves about 0.40 KWH of electricity.
SCIENCE
ENVIRONMENTAL
BENEFITS OF RAIN WATER HARVESTING
ENGINEERING
//
D.PARTHIBAN
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millennium BC, farming communities in Baluchistan and Kutch impounded rain water and used it for irrigation dams. ARTIFICAL RECHARGE TO GROUND WATER : Artificial recharge to ground water is a process by which the ground water reservoir is augmented at a rate exceeding that obtaining under natural conditions or replenishment. Any man-made scheme or facility that adds water to an aquifer may be considered to be an artificial recharge system. WHY RAIN WATER HARVESTING: Rain water harvesting is essential because:-
RAIN WATER HARVESTING TECHNIQUES: There are two main techniques of rain water harvestings. 1. Storage of rainwater on surface for future use. 2. Recharge to ground water.
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ENVIRONMENTAL
SCIENCE
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ENGINEERING
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Surface water is inadequate to meet our demand and we have to depend on ground water.Due to rapid urbanization, infiltration of rain water into the sub-soil has decreased drastically and recharging of ground water has diminished.
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The storage of rain water on surface is a traditional techniques and structures used were underground tanks, ponds, check dams, weirs etc. Recharge to ground water is a new concept of rain water harvesting and the structures generally used are :Pits: - Recharge pits are constructed for recharging the shallow aquifer. These are constructed 1 to 2 m, wide and to 3 m. deep which are back filled with boulders, gravels, coarse sand. Trenches:- These are constructed when the permeable stream is available at shallow depth. Trench may be 0.5 to 1 m. wide, 1 to 1.5m deep and 10 to 20 m. long depending up availability of water. These are back filled with filter. Materials. Dug wells:- Existing dug wells may be utilised as recharge structure and water should pass through filter media before putting into dug well.
Recharge wells :- Recharge wells of 100 to 300 mm. diameter are generally constructed for recharging the deeper aquifers and water is passed through filter media to avoid choking of recharge wells.
Spreading techniques :- When permeable strata starts from top then this technique is used. Spread the water in streams/Nalas by making check dams, nala bunds, cement plugs, gabion structures or a percolation pond may be constructed.
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Lateral shafts with bore wells :- For recharging the upper as well as deeper aquifers lateral shafts of 1.5 to 2 m. wide & 10 to 30 m. long depending upon availability of water with one or two bore wells are constructed. The lateral shafts are back filled with boulders, gravels & coarse sand.
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Recharge Shafts :- For recharging the shallow aquifer which are located below clayey surface, recharge shafts of 0.5 to 3 m. diameter and 10 to 15 m. deep are constructed and back filled with boulders, gravels & coarse sand.
D.PARTHIBAN
Hand pumps :- The existing hand pumps may be used for recharging the shallow/deep aquifers, if the availability of water is limited. Water should pass through filter media before diverting it into hand pumps.
Free flow of storm run off into these tanks and water bodies must be ensured. The storm run off may be diverted into the nearest tanks or depression, which will create additional recharge. Urbanization effects on Groundwater Hydrology : Increase in water demand
More dependence on ground water use Over exploitation of ground water Increase in run-off, decline in well yields and fall in water levels Reduction in open soil surface area Reduction in infiltration and deterioration in water quality
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ENVIRONMENTAL
Construction activity in and around the city is resulting in the drying up of water bodies and reclamation of these tanks for conversion into plots for houses.
SCIENCE
DIVERSION OF RUN OFF INTO EXISTING SURFACE WATER BODIES
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Methods of artificial recharge in urban areas : Water spreading
Recharge through pits, trenches, wells, shafts Rooftop collection of rainwater Roadtop collection of rainwater Induced recharge from surface water bodies.
Computation of artificial recharge from Roof top rainwater collection: Factors taken for computation: Roof top area 100 sq.metre for individual house and 500 sq.m. for multi-storied building. Average annual monsoon rainfall - 780 mm. Effective annual rainfall contributing to recharge 70% - 550 mm. Multistoried building
Roof top area
100 sq. m.
500 sq. m.
Total quantity available forrecharge per annum
55 cu. m
275 cu. m.
Water available for 5 member Family
100 days
500 days
Improvement in groundwater levels and yields.
Reduces strain on Special Village Panchayats/ Municipal / Municipal Corporation water supply
Improvement in groundwater quality
Estimated quantity of additional recharge from 100 sq. m. roof top area is 55.000 liters.
ATTRIBUTES OF GROUNDWATER : There is more ground water than surface water Ground water is less expensive and economic resource. Ground water is sustainable and reliable source of water supply. Ground water is relatively less vulnerable to pollution Ground water is usually of high bacteriological purity. Ground water is free of pathogenic organisms. Ground water needs little treatment before use. Ground water has no turbidity and colour.
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Improvement in infiltration and reduction in run-off.
SCIENCE
ENVIRONMENTAL
Benefits of Artificial Recharge in Urban Areas :
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Individual Houses
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Ground water has distinct health advantage as art alternative for lower sanitary quality surface water. Ground water is usually universally available. Ground water resource can be instantly developed and used. There are no conveyance losses in ground water based supplies. Ground water has low vulnerability to drought. Ground water is key to life in arid and semi-arid regions. Ground water is source of dry weather flow in rivers and streams.
What is Acid Rain? Acid rain is a form of air pollution in which airborne acids produced by electric utility plants and other sources fall to Earth in distant regions. The major contributors, called PRECURSORS to the acid are the common air pollutants, like Sulphur dioxide and Nitrogen oxides Through a variety of chemical reactions the gases form Sulphuric acid and Nitric acid, which are the two acids responsible for the acid rain.
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// ENGINEERING
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SCIENCE
In the last four decades, the population of India has increased at a very rapid rate and has more than doubled. The spread of urbanization and the rapid expansion of urban countries across the country have in the absence of basic infrastructure, created vast urban slums. The estimate of the proportion of urban people living in slum varies from 20% to 30% of the population of the urban centers. Each day almost 15,000 people move into urban areas from villages resulting in 25-50% of population of the country live in crowded densely populated cities and major towns. The presence of migrants combined with poor civic amenities in the urban areas creates low living standards for slum dwellers. Improper and inadequate management of urban waste has led to the prevalence of unhygienic conditions that create a breeding ground for all manner of epidemics. However, avoidance of slum creation totally impossible as the city master plan implementation becomes impossible, as all rules and regulations of city planning gets violated. It is very difficult to create sufficient infrastructure within a short interval of time. This ends up with formation of slums, where individual houses do not have proper latrines and not even public tap or borewell water supply system provided for thousands of slum dwellers. There are a number of schemes designed to improve urban infrastructure such as centrally assisted programmes for construction of individual and community latrines. There are schemes for water supply to small towns with population less than 20,000. Initiatives create infrastructure for the urban poor include, schemes to provide drinking water, drainage and lighting to notify slums. The urban basic service schemes – 1986 promotes women and child development, low cost water supply and sanitation. A programme for environmental improvement of urban schemes was introduced in 1974.
ENVIRONMENTAL
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How is acid produced? Nitric oxide can react with oxygen O2 to form nitrogen dioxide which can be broken down again by Sunlight(hv )to give Nitric oxide and an oxygen radical (O). 2NO + O2 = 2N2NO2 + hv = NO+O The oxygen radical then enables the formation of Ozone (O3) O+O2= O3 The presence of ozone causes the formation of more nitrogen dioxide by its reaction with nitric oxide. NO+O3= NO2+O2 Or, the oxygen radical reacts with water to give the hydroxyl radical (OH) O+H2O = 2OH.
While Nitric oxide and Sulphur dioxide are produced biogenic ally (in nature), there are major anthropogenic (man made) sources of both these polluting gases. Sometimes, natural production of the gases is much higher than human production, but these natural emissions tend to be spread over large area, dispersing their effects, while the man – made emissions are concentrated around the source of their production. Biogenic Sources (Or Natural Sources) Volcanic eruptions and decay of organic matter produce significant amounts of Sulphur dioxide. Nitrogen oxides are also generated by push fires as well as by microbial process (in Soil) and lightning discharges.
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Where does the ‘precursors’ come from?
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NH2+HO= HNO3SO2+2HO = H2SO4
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HO+NH= HNO2
SCIENCE
acid (HNO3). It also combines with Sulphur dioxide to produce Sulphuric acid
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This radical then reacts with nitric oxide to give nitrous acid (HNO2) and nitrogen dioxide to give nitric
Nitrogen oxides are produced mainly from the burning of fossil fuels such as Diesel and petrol in automobiles and from power stations burning coal. Sulphur dioxide is formed primarily in the burning of (Sulphur containing) Coal, fossil fuels and in metal smelters. How are acids deposited? •Acid pollutants are deposited on the ground either in wet form through rain, fog or snow. As dry matter, such as gases or particulates, falling directly from the atmosphere to the ground.
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ENVIRONMENTAL
Anthropogenic Sources (or man made sources)
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•The term acid deposition describes all these possibilities and therefore – generally preferred to “acid rain”. •Environmental problems from dry deposition tend to occur closer to the source of the pollution. Wet deposition can occur upto hundreds of kilometer away in a different region or country, because microscopic aerosol droplets can be carried in clouds. How can we reduce acid rain? •The most effective way to reduce the incidence of acid deposition is to reduce the emission of its causes – The “PRECURSORS”, nitrogen oxides and Sulphur dioxide. •Nitrogen oxide reduction. The main method of lowering the levels of nitrogen oxides is by a process known as “Catalytic reduction”. Catalytic reduction is used in Industry & in motor vehicles.
In a motor vehicles the Catalytic converter will convert much of the nitric oxide from the engine gases to the nitrogen and oxygen. Nitrogen is not there in the actual fuels or power stations. It is introduced from the air when combustion occurs. Using less air in combustion can reduce emissions of nitrogen oxides.
Most Complex is by the process of “FLUE GAS DESULPHURISATION” and “FLUIDISED BED COMBUSTION”. Physical coal cleaning: Coal can be cleaned because, Sulphur in Coal is often in the form of mineral impurities (pyrites). This is achieved by finely crushing the Coal. Flue gas Desulphurization: In this method the Sulphur dioxide (flue gas) is absorbed using lime stone. This method is the most effective of removing Sulphur dioxide The process generates Solid wastes (Calcium Sulphate, CaSO3 and CaSO4) which require disposal. CaCO3(limestone)+SO2=CaSO3+CaSO4+CO2+H2O. Fluidized bed combustion
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There are several method to lower the Sulphur dioxide emission from Coal – fired stations. Simplest of the lot is using Coal with low Sulphur content and physical coal cleaning.
SCIENCE
Sulphur dioxide reduction:
ENVIRONMENTAL
Temperatures can be lowered by using processes such as two stage combustion and flue gas recirculation water injection or by modifying the design of the burner.
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Temperature also has an effect on emission. Lower the temperature of combustion, lower will be the production of nitrogen oxides.
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Example
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In this process, coal is crushed and passed into a fluidized “bed” for combustion. The bed consists of fine particles of an absorbent material such as lime stone. Hot air is passed through it and this causes the particles to behave as through they are a fluid. The sulphur dioxide can then be absorbed by the lime stone particles in the bed. Fluidized bed combustion can be operated at lower temperatures and therefore produce less nitrogen oxide, but once again, solid waste is created and requires disposal. What is affected by acid rain? The acids in the acid rain can react chemically with any object they contact. Acids are corrosive chemical that react with other chemical by giving up hydrogen atoms. Acid rain or acid deposition has an adverse effect on environmental eco system as well as humans, animals,buildings, textiles. etc.
Plants and Animals: The effects of acid rain on wild life can be far reaching, if a population of one plant or animal is adversely affected by acid rain, animals that feed on that organism may also suffer ultimately an entire ecosystem may become endangered.Land animals dependent on aquatic organisms are also affected. Man made structure: Acid rain and dry deposition of acidic particles damage building, statues, automobiles, and other structures made of stone metal or any other material exposed to weather for long periods. Parthenon in Greece and the Taj- Mahal in India, are deteriorating due to acid deposition.
Human health: Acidification of Surface water cause little direct harm to human health, it is safe to swim in even the most acidified lakes. In the air: acids join with other chemicals to produce urban smog, which can irritate the lungs an make breathing difficult, especially for people with respiratory diseases. Solid particles of sulphates can damage the lungs.
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// ENGINEERING
Surface water: Acid rain falls into streams, lakes and marshes. Due to this the water life is destroyed. All Norway’s major rivers have been damaged by acid rain, severely reducing the fish life.
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Agriculture: Most farm crops are less affected by acid rain than the forest. Farmers can prevent acid rain damage by monitoring the condition of the soil and, when necessary, adding crushed lime stone to the soil to neutralize acid.
SCIENCE
Acid rain has been blamed for the decline of Spruce forests on the highest ridges of Apalachian Mountains in the eastern United States. In the black forest of South Western Germany, half of the trees are damaged from the acid rain.
ENVIRONMENTAL
Trees: Removal of useful nutrients from the soil, acid rain slows the growth of plants, particularly trees. It also attacks trees more directly by eating holes in the waxy coating of needles & leaves, causing brown dead spots.
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Soil: Acid rain dissolves in Soil and washes away nutrients needed by the plants. It can also dissolve toxic substances such as aluminum & mercury, releasing these toxins to pollute water or to poison plants that absorb them.
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Acid rain and Global warming: Acid pollution has one surprising effect that may be beneficial. Sulphates in the upper atmosphere reflect some sunlight out into the space, and thus tend to slow down global warming. OZONE LAYER DEPLECTION
B B B B B
The total amount of zone in a column overhead is measured in “DOBSON Unit” (DU), 1DU=0.01mm Ozone layer a region of the atmosphere from 19 to 48 km above the earth’s surface. Although the concentration of ozone is the ozone layer is very small, it is vitally important to life because it absorbs biologically harmful ultra violet (UV) radiation emitted from the Sun. UV radiation is divided into three categories basd on its wave length, ie., UV-A, UV-B, UV-C. Most of the UV-A (315 to 400nm) reaches the surface this radiation is significantly less harmful, although it can potentially cause genetic damage. UV-B (280 to 315nm) radiation is the main cause of Sun burn; excessive exposure can also cause genetic damage, resulting in problems such as Skin cancer. It rapidly damages biota of all types. UV-C < 280nm, the ozone layer is very effective at screening out UV-B, for radiation with a wave length of 290nm, the intensity at Earth’s surface is 350 million times weaker at the top of the atmosphere.
B B B
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Stratospheric Ozone layer: Atomic oxygen O, oxygen molecules O2 and Ozone O3 are involved in the ozone – oxygen cycle. Ozone is formed in the Stratosphere when oxygen molecules dissociate after absorbing the ultraviolet photon whose wave length is shorter than 240nm. This produces two oxygen atoms. The atomic oxygen then combines with O2 to create ozone O3Ozone molecules absorb UV light between 310 and 200nm, following which ozone splits into a molecule of O2 and O. The process O3 generation and splitting are as per the equations below.
B
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B
Dobson established a world wide network of ozone monitoring stations which operate even today.
O2
----- O+O
O2+O O2+O
----- O3 O3
-----
O3+O ----- 2O2Under normal conditions the creation and destruction of ozone molecules is roughly constant and ultimately result in effect absorption of short wave length ultraviolet raditions in the stratospheric region.Life underneath is thus protected from the harmful solar radiations. The average thickness of ozone layer in stratosphere is approximately 300DU.
Ozone hole: Certain human produced pollutants lead to destroy the stratosphere ozone and causing an imbalance between formation and dissociation of ozone. This decrease in the ozone level is called depletion or thinning of ozone layer or zone hole. Cause of Ozone depletion:
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ENGINEERING
B
Its properties were explored in detail by G.M.B.DOBSON, a British Meteorologist.
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B
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B
Ozone layer was discovered by a French physicist CHARLES FABRY and HENRI BUISSON in 1913.
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B
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Ozone can be destroyed by a number of free radical catalyst, like hydroxyl (OH), the nitric oxide (NO), atomic chlorine (Cl) and Bromine (Br). All of these are generated by both natural and anthropogenic (man made) sources. At preset most of the OH and NO is the stratosphere is of natural origin, but human activity has dramatically increased the chlorine and bromine. •These elements are found in certain stable organic compounds, particularly chlorofluorocarbons (CFC’s) •Once in the stratosphere, the Cl and Br atoms are liberated from the parent compounds by the action of ultra violet light and can destroy ozone molecules in a catalytic cycle. Cl + O3 = ClO+O2ClO+0= Cl+O2In sum, O3+O = O2+O2
This enhances the Surfaces for chemical reactions that lead to ozone destruction. Most of the ozone that is destroyed is in the lower stratosphere. Warming temperatures near the end of Spring break up the vortex around mid – December. As warm ozone – rich air flows in from lower latitudes, the PSC’s are destroyed, the ozone depletion process shuts down, and the ozone hole heals. The decrease in the ozone layer was predicted in the early 1980’s to be roughly 7% over a sixty – year period. The term Ozone depletion for distinct but related, observations: a slow decline (about 3% per decade) in the total amount of ozone in the earth’s stratosphere and much larger, but seasonal,
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// ENGINEERING AND SCIENCE ENVIRONMENTAL
A Single chlorine atom would keep on destroying ozone for up to two years. On a per atom basis, bromine is even more efficient than chlorine at destroying ozone, but there is much less bromine in the atmosphere. As a result both chlorine and Bromine contribute significantly to the overall ozone depletion. CFC’s were used in air – conditioning / cooling units as aerosol spray propellants prior to the 1980’s and in the cleaning process of electronic components. CFC’s when reach the Stratosphere, are dissociated by ultraviolet light to relase chlorine atoms. The chlorine atoms act as Catalyst, and can breakdown many thousands of ozone molecules before removed from the Stratosphere. It is calculated that CFC molecules takes an average of 15 years to go from Ground level upto the upper atmosphere, and it can stay there for about a century, destroying up to one hundred thousand ozone molecules during that times. The Antarctic ozone hole is an area of the Antarctic Stratosphere in which the recent ozone levels have dropped to as low as 33% of their Pre- 1975 values. The ozone hole occurs during the Antarctic spring, from September to early December, as strong westerly winds start to circulate around the continent and create an atmospheric container, within this “polar vertex”, over 50% of the lower stratospheric ozone is destroyed during the Antarctic spring. The overall cause of ozone depletion is th presence of chlorine – containing source gases (primarily CFC’s and related hydrocarbons). In the presence of UV light, these gases dissociate releasing chlorine atoms, which then go on to catalyze ozone destruction. The chlorine catalyzed ozone depletion can take place in the gas phase, but it is dramatically enhanced in the presence of polar stratospheric clouds (PSC’s) Polar Stratospheric clouds form during winter. In the extreme cold temperatures would be around – 800C, without Sunlight and the ‘polar vertex’ trapping the chill air.
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Final result is an oxygen molecule and a chlorine atom, which then reinitiates the cycle.
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decrease in Stratospheric ozone over the earth’s polar regions during the same period. Cause of both trends is believed to be the Catalytic destruction of ozone by atomic chlorine and bromine. The reactions that take place on polar stratospheric clouds (PSC’s) are of great importance. The PSC’s only form in extreme cold. The Antarctic stratosphere is colder than the Arctic, and the PSC’s form more readily, which is the reason for ozone hole formation over Antarctic. This is why the Arctic zone holes are not as deep. In middle latitudes declines are bout 3% below pre-1980 values for 35-60N and bout 6% for 35-60S. In the topics, there are no significant trends.
Consequences of Ozone depletion:
Since the ozone layer absorbs UV-B light from the Sun, ozone layer depletion is expected to
An increase of UV radiation would also affect crops like rice. At ground level ozone is generally recognize to be a health risk, as ozone is toxi due to its strong
Acid Rain-Causes & Consequences ACID RAIN
As the name suggests, acid rain is just rain which is acidic. The rain becomes acidic because of gases which dissolve in the rain water to form various acids. In general about 70 percent of acid rain comes from sulphur dioxide (SO2), which dissolves into the water to form sulphuric acid. The rest comes from various oxides of nitrogen mainly NO2 and NO3, collectively called NOx, Oxides of carbon
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In 1994 UN General, assembly voted to designate September 16 as “World Ozone day”. A 2005 IPCC summary of ozonic issue observed that global average amount of ozone depletion is now approximately stabilized. The thickness of the ozone layer over Europe which has decreased by 8% since the 1980’s has now slowed down to about 4% a decade. The Antarctic ozone hole reached its largest ever size in September 2000 at 11.5 million Square miles.
ENVIRONMENTAL
Current events and future trends.
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oxidant propertiesPresently, ozone at ground level is produced mainly by the action of UV radiation as exhaust gases, from vehicles. Lower trophic level organisms shall be the worst sufferers as they have a simple cell wall for their protection against UV radiation. With the primary tropic levels drastically impaired the entire ecosystems could collapse.
D.PARTHIBAN
increase surface UV-B levels, which could lead to damage, including increase in skin cancer. Scientists have estimated that a one percent decrease in Stratospheric ozone would increase the incidence of skin cancers by 2% A direct correlation has been observed between cataract formation in eyes and UV radiations.
Page: These gases are produced almost entirely from road transport. o 62 % sulphuric acid, SO2 + H2O o 32 % nitric acid and, NOX + H2O o 5 % hydrochloric acid, Cl2 + H2O o 1 % carbonic acid, CO2 + H2O
burning fossil fuels, mainly in power stations and
H2SO4 HNO3 HCl + HOCl H2CO3
ENVIRONMENTAL
SCIENCE
Acid rain causes lakes and rivers to become acidic, killing off fish – [Ex: All the fish in 140 lakes in Minnesota have been killed, and the salmon and trout populations of Norway's major rivers have been severely reduced] because of the increased acidity of the water. Short-term increases in acid levels kill lots of fish, but the greatest threat is from long-term increases, which stop the fish reproducing. The extra acid also frees toxic metals which were previously held in rocks, especially aluminium, which prevents fish from breathing. Single-celled plants and algae in lakes also suffer from increased acid levels.
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D.PARTHIBAN // ENGINEERING
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A very highly publicized problem is the effect of acid rain on trees. Conifers appear to be particularly affected, with needles dropping off, and seedlings failing to produce new trees. When acid rain falls on trees, it makes their leaves turn brownish-yellow and the tree can no longer carry out photosynthesis properly The acid also reacts with many nutrients the trees need, such as calcium, magnesium and potassium, which starves the trees. The trees are then much more susceptible to other forms of damage, such as being blown down, or breaking under the weight of snow. Many toxic metals are held in the ground in compounds. However, acid rain can break down some of these compounds, freeing the metals and washing them into water sources such as rivers. In Sweden, nearly 10,000 lakes now have such high mercury concentrations that people are advised not to eat fish caught in them. As the water becomes more acidic, it can also react with lead and copper water pipes, contaminating drinking water supplies. In Sweden, the drinking water reached a stage where it contained enough copper to turn you hair green! Presence of more amount of copper can also cause Diarrhoea in young children, and can damage livers and kidneys. Acid rain can cause buildings, statues and bridges to deteriorate faster than usual. Acid rain affects certain materials, particularly limestone and marble. The acid dissolves the calcium carbonate in the stone, and this solution evaporates, forming crystals within the stone. As these crystals grow, they break apart the stone, and the structure crumbles. This picture shows how much the gargoyle on the left has been damaged by acid rain - the gargoyle on the right has been reconstructed.
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Birds can be harmed if they live in affected waters or feed on fish living in affected waters.
There are several places around the world affected by acid rain and here are the main ones. The Northeastern section of the United States where acid rain is caused by high numbers of factories and power plants is one affecte affected area.
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Also Southeastern section of Canada is affected and the main cause is factories in the TorontoHamilton area and possibly large numbers of automobiles. The Taj Mahal in India, one of the ten wonders of the world, is being constantly threatened by acid rain. Some famous statues, such as the Lincoln Memorial and Michael Angelo's statue of Marcus Aurelius, have started deteriorating because of acid rain. In London in 1952, very thick acid smog killed 4,000 people.
Turn off lights when you leave a room If you have a car, don't use it for short journeys Get your parents to insulate their house properly Basically, anything at all that uses less energy
Green House Effect-Causes & Consequences GREENHOUSE GASES
The following industries are among those that emit a great deal of pollutants into the air: thermal power plants, cement, steel, refineries, petro chemicals, and mines. Air pollution results from a variety of causes, Dust storms in desert areas and smoke from forest fires and grass fires contribute to chemical and particulate pollution of the air. The source of pollution may be in one country but the impact of pollution may be felt elsewhere.
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ENGINEERING
AND
SCIENCE
The best approach to reduce acid rain is to reduce the amount of NOx ,SO2 and CO2 being released into the atmosphere. Fitting a catalytic converter to a car can reduce the emissions of NOx by up to 90 percent, but they are very expensive, and cause more carbon dioxide to be released, which contributes to the greenhouse effect. Best option is not to burn fossil fuels, but to use alternative energy sources which are less polluting. SO2 emissions from power stations can be reduced before, during, or after combustion. If a fuel with low sulphur content is burned, not much sulphur dioxide will be formed. However, low sulphur fuels are more expensive because they are in greater demand, and although highsulphur fuels can be treated to reduce their sulphur content, this is very expensive. The SO2 created during combustion can be absorbed if an appropriate chemical adsorbent (such as limestone) is present as the fuel burns. Once the fuel has been burned, the SO2 can be removed from the exhaust gases. Most systems spray a mixture of limestone and water onto the gases. This mixture reacts with the SO2 to form gypsum, a useful building material. The best way to reduce them is not to use as much energy in the first place. You can help in lots of ways:
ENVIRONMENTAL
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CONTROL METHODS
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The discovery of pesticides in Antarctica, where they have never been used, suggests the extent to which aerial transport can carry pollutants from one place to another. Probably the most important natural source of air pollution is volcanic activity, which at times pours great amounts of ash and toxic fumes into the atmosphere. The eruptions of such volcanoes as Krakatoa in Indonesia, Mt. St. Helens in Washington, USA and Katmai in Alaska, USA, have been related to measurable climatic changes.
GREEN HOUSE GASES
ENVIRONMENTAL
Gases stay in the air for a long time and warm up the planet by trapping sunlight. This is called the “greenhouse effect” because the gases act like the glass in a greenhouse. Some of the important greenhouse gases are carbon dioxide, methane, and nitrous oxide. Carbon dioxide is the most important greenhouse gas, and it comes from the burning of fossil fuels in cars, power plants, houses, and industry. Methane is released during the processing of fossil fuels, and also comes from natural sources like cows and rice paddies. Nitrous oxide comes from industrial sources and decaying plants. The greenhouse effect can lead to changes in the climate of the planet. Some of these changes might include more temperature extremes, higher sea levels, changes in forest composition, and damage to land near the coast. Human health might be affected by diseases that are related to temperature or by damage to land and water. The greenhouse effect causes trouble by raising the temperature of the planet. The actual rise is not very much, but the Earth's ecosystem is very fragile, and small changes can have large effects.
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ENGINEERING
GREEN HOUSE EFFECT
D.PARTHIBAN
CONTRIBUTION 64 % 19 % 11 % 6% 0.4 %
AND
GAS Carbon dioxide Methane Chlorofluorocarbons Nitrous oxide Sulfur hexafluoride
SCIENCE
S.NO 1 2 3 4 5
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The carbon dioxide comes mainly from burning fossil fuels in power stations, which also causes acid rain. It is also created by living animals breathing, and is naturally converted by plants back to oxygen. However, deforestation is reducing the planet's carbon dioxide absoring capability. Nitrous oxide is a by-product of nylon production, and is also released by fertiliser use in agriculture. The extra methane is produced in coal mining, natural gas production and distribution (natural gas is methane), and waste disposal. One fifth of all methane generated by human activity comes from microbial decay of organic material in flooded rice fields.
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AND SCIENCE
There are some natural greenhouse gases: water vapour, nitrous oxide, carbon dioxide, methane and ozone. However, over the past fifty years, production of carbon dioxide, nitrous oxide and methane has risen sharply, and a new type of chemical - the chlorofluorocarbon, or CFC - has been introduced as a refrigerant, solvent and aerosol propellant, but it is also a very powerful greenhouse gas, because it can trap a lot of radiation - one molecule of CFC is 12,000 to 16,000 times as effective at absorbing infra-red radiation as a molecule of carbon dixide
ENVIRONMENTAL
Problems of The Greenhouse Effect
ENGINEERING
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STRUCTURE OF THE ATMOSPHERE
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AND SCIENCE
The Earth is kept warm by it's atmosphere, which acts rather like a woolly coat - without it, the average surface temperature would be about -18 degrees Centigrade. Heat from the sun passes through the atmosphere, warming it up, and most of it warms the surface of the planet. As the Earth warms up, it emits heat in the form of infra-red radiation - much like a hot pan emits heat even after it's taken away from the cooker. Some of this heat is trapped by the atmosphere, but the rest escapes into space. The socalled "greenhouse gases" make the atmosphere trap more of this radiation, so it gradually warms up more than it should, like a greenhouse (although a greenhouse actually does this by stopping warm air rising and escaping from it).
ENVIRONMENTAL
WHAT CAUSES GREEN HOUSE EFFECT?
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ENVIRONMENTAL
SCIENCE
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The diagram shows where the ozone layer is positioned relative to other layers in the atmosphere of the earth. The diagram does not show the entire atmosphere that surrounds the earth, above the mesosphere there are two other layers, the thermosphere and the exosphere. The exosphere is around 700km from the Earth's surface. The distance between an object and the level of the sea is defined as the object's altitude. On the diagram is an indication of the variation of temperature as altitude increases
D.PARTHIBAN
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ENGINEERING
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PICTORIAL REPRESENTATION OF GLOBAL WARMING
could cause global warming. In 1988 the united nations environmental program and world meteorological organization formed Intergovernmental Panel on Climate Change(IPCC)with 700 scientist from 100 countries. The report said that “recent changes in the world’s climate have had severe impacts on more than 420 different physical and biological systems” They reported that “we have altered the chemical composition of the atmosphere through the buildup of green house gases-primarily carbon dioxide, methane and nitrous oxide. More than 30 billion tons of CO2(containing 8 billion tons of carbon) is released every year due to burning fossil fuels, manufacturing cement, burning forest and grassland and by other human activities. Methane absorbs sun radiation 20 to 30 times as much as CO2 absorbs.
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SCIENCE
Global climate change due to human activities is the most important environmental issue. Svante Arrhenius* predicted that increase of CO2 level in the atmosphere due to coal burning
ENVIRONMENTAL
Causes for climate change
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CLIMATE CHANGE
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Methane is released from animal’s wastes, wet-rice paddies, coal mines, land fills and pipeline leakages
Chloro fluoro carbons (CFC) are also powerful IR radiation absorbers.CFC release have declined since its use were banned. but CFC already present in the atmosphere will persist for longer period of time Nitrous oxide is produced by burning organic matters and by soil denitrification.
CFC’s and Nitrous oxide together accounts for 17% of global warming *received Nobel Prize in 1895 for this invention
Carbon di-oxide is a natural constituent of atmosphere, but now, its concentration is increasing at an alarming rate. According to an estimate, CO2 level is expected to be doubled by 2030 A.D. The term ‘Green House Effect’ is also called as ‘Atmospheric Effect’, ‘Global Warming’ or ‘CO2 Problem’. Human activities are changing the composition as well as behavior at an unprecedented rate. The pollutants form a wide range of human activities are increasing the global atmospheric concentration of certain heat trapping gases, which act like a blanket, trapping close to the surface that would otherwise escape through the atmosphere to the outer space. This process is known as ‘Green House Effect’. Green House is that body which allows the short wave length incoming solar radiation to come in, but does not allow the long wave outgoing terrestrial infra red radiation to escape. The progressive
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ENVIRONMENTAL
CLIMATIC CHANGE AND GLOBAL WARMING
SCIENCE
AND
ENGINEERING
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D.PARTHIBAN
Consequences of climate change
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warming up of the earth’s surface due to blanketing effect of manmade CO2 in the atmosphere is called ‘Green House Effect’. (Figure 1).
The four major green house gases, which cause adverse effects are CO2, CH4, N2O and CFC’s. Among these CO2 is the most common and important green house gas. In addition, ozone and SO2 are also act as serious pollutants in causing global warming.
GREEN HOUSE EFFECT
Figure 1 Green House Effect
Sources A number of industrial as well as agricultural operations generate and emit waste gases into the atmosphere. Burning of fossil fuel emit CO2, growing paddy, or live stock releases methane. The use of aerosols and coolants in refrigerators and air conditioning devices or sprays releases
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ENVIRONMENTAL
SCIENCE
AND
ENGINEERING
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D.PARTHIBAN
Under normal concentrations of CO2, the temperature of the earth’s surface is maintained by the energy balance of the sun’s rays that strike the planet and the heat is radiated back into the outer space. However, when concentration of CO2 in the atmosphere increases, the thick envelope of this gas prevents the heat from being re-radiated out. The heated earth can radiate this absorbed energy as the radiation of longer wave length.
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chlorofluorocarbons into the atmosphere. These gases create a canopy in the atmosphere and trap the solar radiation reflected back from the earth’s surface leading to atmospheric and climatic changes.
Green House Effect on Global Climate
Some potential effects associated with the enhanced green house effect and the associated global warming is as follows. Water Resources Due to changes in precipitation pattern and increased evaporation the quality and quantity of water available for drinking, irrigation, industrial use, electric generation, aquatic life, etc., are significantly affected. Coastal Resources An estimate of 50 cm rise in sea level by the year 2100, could inundate more than 8000 Km of dry land. Health Changing pattern of temperature and precipitation may produce new breeding sites for pests, shifting the range of infectious diseases. Heat stress mortality could increase due to higher temperature over longer periods.
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// ENGINEERING AND
The global warming trend can cause significant climatic changes. Human society is highly dependent on the earth’s climate pattern and human adaptations determine the availability of food, fresh water and other resources for sustaining life. The social and economic characteristics of a society have also been shaped largely by adapting to the seasonal and year to year patterns of temperature and rainfall.
SCIENCE
Scientists believe, the average global temperature will be higher than ever in the past thousand years.
ENVIRONMENTAL
As a result of rise of temperature of earth, the oceans get warm up and sea level would rise flooding low lying regions. A slight increase in sea level could have profound effects on habitation and coastal land. In temperate regions, the winter will be shorter and warmer and the summer will be longer and hotter. A warmer climate is likely to make some cities extremely hot. There will be enormous increase in rainfall, but the problem of desertification, drought and soil erosion will further worsen. The most obvious effect of climate change will be on agriculture. Because CO2 is a natural fertilizer, the plants will grow larger and faster with increasing CO2 in the atmosphere. The abnormal fast growth results in increase of yield but the soil fertility goes down at a very fast rate.
D.PARTHIBAN
A huge amount of CO2 gets introduced into the environment from furnaces of power plants, fossil fuel burning, vehicular exhaust and breathing of animals, but the ocean may not be able to absorb this increased CO2 and the plants also cannot utilize the whole during photosynthesis. So, much of CO2 is still left in the atmosphere, which is supposed to be responsible for increasing the atmospheric temperature.
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Oceans Oceans can provide sources for the increased water vapour because of the earth’s increased temperature. On the other hand, the thermal holding capacity of the oceans would delay and effectively reduce the observed global warming. In addition, oceans play an important role in the global green house gas budgets. The ocean biota, primarily phytoplankton is believed to remove at least half of the anthropogenic CO2 added to the atmosphere. The ocean sink of CO2 is called ‘Biological CO2 Pump’. Vegetation Vegetation changes due to climatic change would affect the hydrologic cycle. The biggest impact of CO2 induced climatic change would be changing precipitation form lead to overall lower rainfall amount or drought during growing season with increased frequency and severity. However, the rise in atmospheric CO2 should cause increase in photosynthesis, growth and productivity of the earth’s vegetation. Thus the change in climate on vegetation has less adverse impact. Higher temperature could increase forest susceptibility to fire, disease and insect damage.
Global Climate It is even postulated by scientists that melting of glaciers and the release of the resultant cold water in large quantities could affect the major sea currents in the Atlantic Ocean. The ocean currents of Atlantic in fact, act as a heat conveyer of the planet regulating the global climate. If the heat conveyer is interrupted, the northern hemisphere would plunge into an ice age and the southern hemisphere will be facing severe drought. In general, global warming is likely to make the weather more unpredictable in the coming years.
// ENGINEERING
Increased temperature would tend to melt ice and result in increased absorption of solar energy by the ocean. However, a decrease in sea ice would also lead to larger heat fluxes from the ocean to the atmosphere. Thus, the interaction among the atmosphere, the ocean, sea ice and the interaction of sea ice to climate change need to be observed and quantified.
AND
Sea Ice
SCIENCE
Global warming will lead to an increase in the amount of water vapour in the atmosphere and because water vapour is a powerful green house gas, lead to an increase into the warming. However, tropical storm clouds reach higher in the atmosphere under warmer conditions. Then the clouds would produce more rain thus adding less water vapour to the middle troposphere.
D.PARTHIBAN
Clouds and Water Vapour
The major steps to be taken for the reduction of green house gases includes, improving the energy efficiency of electric generation, as well as switching to less polluting fossil fuels. Following are some of the suggestions to prevent global warming. B
Reduction and elimination of green house gases emission that is disturbing the climate. Clean electricity technologies including wind turbine, solar panels and hydrogen fuel cells are continually improving, becoming more efficient, economical and capable of competing with polluting gas and coal power plants.
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ENVIRONMENTAL
Prevention of Global Warming
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B
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B
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Bio-fuels including ethanol and bio-diesel could substantially cut down the CO2 emission from automobiles.
Sustainable farming and forestry techniques look up carbon in plants and soils and provide new revenues to rural communities. Besides protecting the climate, CO2 emission control techniques dramatically reduce air pollution provide communities with higher quality of life and climate. Conservation and produce energy that causes no environmental damage with cost less than building new power plants. They lower electricity bills and reduce constraints on energy systems.
PHOTOCHEMICAL SMOG Smog is a mixture of smoke and fog. Oxides of nitrogen and hydrocarbons are let into the atmosphere from automobile exhaust. The action of sunlight on these pollutants leads to the formation of peroxyacyl nitrate which causes photochemical smog. N2 + O2 2NO 2NO + O2 2NO2
NO 2 sunlight NO O O + O2 O3 RCH
CHR
+ O2
RCO3 RCH2
(hydrocarbon)
RCH 2
+ O2
RCH 2 O 2
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// ENGINEERING AND
In contrast to global warming there is another phenomenon called ‘Global Dimming’. Scientists have observed that 2-4% reduction in the amount of solar radiation reaching the earth’s surface, due to increase in cloud cover aerosols and particulates in the atmosphere. Higher temperature leads to an increased cloud cover. The scattered light through the clouds boosts the plant’s adsorption of CO2 and photosynthesis process. Thus global dimming is a process working against global warming to some extent.
SCIENCE
Global Dimming
ENVIRONMENTAL
The Kyoto protocol is a legally binding international agreement to reduce green house gas emissions. It was initially negotiated during a meeting held at Kyoto, Japan in 1977. The protocol commits in industrialized countries to reducing emissions of six green house gases by 5% before 2012.
D.PARTHIBAN
Kyoto Protocol
Page: RCH 2 O 2
+ NO
RCH 2 O
+ O2
HO2
NO
RCHO
+
O
RC
HO
RCH 2 O
NO2 +
HO2 RCHO
HO NO 2
RC
+ O2
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O
NO
RCO 3
+ H2O RC
O
O O NO2 Peroxyacyl nitrate (PAN) OZONE DEPLETION Formation of ozone in the atmosphere:
Causes CF2 Cl2
of ozone depletion Chlorofluorocarbons (CFCs) are used as refrigerants, aerosols and as industrial solvents. CFCs are noncombustible and volatile. They reach the atmosphere and are broken down into chlorine free radicals by uv radiations.
uv - C
CF2 Cl
Cl
The chlorine free radical brings about the degradation of ozone
ClO O
Cl O 3
ClO O 2
Cl O 2
Thus CFCs reduce the concentration of ozone in the atmosphere causing ozone hole.
Ill effects Due to ozone hole, the uv radiation increases causing eye infections, skin cancer in human beings and decrease in photosynthesis in plants.
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D.PARTHIBAN //
and hence a dynamic equilibrium is set up due to which the concentration of ozone in the atmosphere remains constant. The ozone layer protects the earth from the harmful uv radiations. If the concentration of ozone is reduced (ozone depletion), the concentration of uv radiations reaching the earth increases. This leads to irritation of the eyes, skin cancer and damage to immune system in human beings In agriculture it causes decrease in productivity.
ENGINEERING
O + O2 The products formed combine again to form ozone O + O2 O3
AND
uv - C 2O
SCIENCE
O2 O3
Ozone absorbs uv radiations and is broken into atomic and molecular oxygen.
ENVIRONMENTAL
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The temperature on the earth’s surface is raised and this leads to global warming.
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Agriculture Housing Transportation Industries Water resources projects including irrigation projects Power Generation Mining Tourism Socio-Economic activities Defence related activities Petroleum processing
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// ENGINEERING AND
All living beings including man are dependant on their environment for existence. But every manmade activity has some impact on the environment. More often it is harmful than benign. But human beings cannot live without taking up these activities for their food, shelter, comfort, security and many other needs. The following activities cause major impacts on the environment:
SCIENCE
Environmental Impacts of Human Activities
ENVIRONMENTAL
Green house effect Most of the infrared radiation from the sun is absorbed by the earth’s surface and a small amount of it is reflected back. An equilibrium is established and this keeps the earth’s temperature constant. Green house gases such as carbon dioxide, methane, ozone and CFCs absorb the infrared radiations and reemit into the earth. This raises the temperature of earth. This is called green house effect and leads to global warming. Sources: The main cause for green house effect is carbon dioxide. The sources of carbon dioxide are combustion of fuels, degradation of vegetable matter, deforestation and industrial activities. Ill effects: Due to green house effect and global warming, glaciers and icecaps would melt raising the sea level. The winters would be shorter and summers would be longer. Weeds , insects and rodents thrive better in warm conditions and these damage the crops. Control: Use of non fossil fuels as energy sources, using alternatives for CFCs, afforestation are some of the methods for control of green house effect.
D.PARTHIBAN
Control of ozone depletion: Ozone depletion can be controlled by using hydrochlorofluorocarbons and hydrofluoroalkanes in place of CFCs. These contain more hydrogen in their molecule and undergo oxidation readily.
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Urbanization Commercial deforestation Providing public amenities such as water supply, sanitation, electricity, telephone, transportation etc., Religious places – public activities
The list is not exhaustive. Every activity of the man from birth to death has its impact on the environment. Some of the major impacts are listed below :
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Transportation
- Deforestation for constructing roads and railways - Utilization of valuable agricultural land for construction of airports which change the land use pattern - Air pollution - Noise pollution - Disruption of wild life habitats
Extraction of construction material Cutting of forests Energy utilization Stress on water resources Urban centres impose heavy burden on the environment - Disruption of storm water drainage pattern
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Housing
Deforestation Submergence of forest and other lands Water logging problems Evacuation and rehabilitation of people and villages - Disturbance to wild life - Masquito breeding
ENGINEERING
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Water Resources projects
SCIENCE
Impacts - Soil erosion - Discharge of nutrients into water bodies / ground water - Discharge of pesticides into the environment. These pesticides end up in the food chain of the ecosystem. Endosulfan problem of cashew nut farms in Kerala which has crippled human beings is a living example. - Imposing Water burden on water resources Water pollution
ENVIRONMENTAL
Activity Agriculture
D.PARTHIBAN
Activities and Impacts
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- Nuclear power plants carry the risk of radioactive hazards - Global warming / climate change and acid rain are related to combustion of fossil fuels in thermal power plants. Mining
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Deforestation Large tracts of land is made barren Air pollution Water pollution Soil erosion Transportation of ores imposes heavy burden on transport facilities
Tourism and Religious activities
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Create congestion Transport problems Sanitation problems Water supply related problems Spread of diseases Social problems Accumulation of plastic and other solid wastes
Human Habitation and Urbanization
- Growth of urban centres create all sorts of environmental problems like air,
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Hydroelectric plants – submergence of valuable lands, deforestation, disruption of wild life etc., Thermal power plants create water pollution, air pollution and thermal pollution problem besides requiring large quantity of water Power transmission lines lead to deforestation Thermal power plants require coal. Coal mining is environmentally critical activity. Also coal has to be hauled over long distances creating transportation related problems
ENGINEERING
-
AND
Power Generation
SCIENCE
- Pressure on land and other natural resources for raw material - Water pollution - Air pollution - Noise pollution pressure on transport systems
ENVIRONMENTAL
Industries
D.PARTHIBAN
- Pollution of marine waters due to harbours
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water and noise pollution, traffic related problems sanitation problems etc., Solid waste generation Water burden Social tensions
Environmental Protection Acts Introduction
Various statues / legislations are enacted in India exclusively for Environment Protection are,
The The The The The The
Water (Prevention and Control of Pollution) Act, 1974 Air (Prevention and Control of Pollution) Act, 1981 Environmental Protection Act, 1986 Forest Conservation Act, 1980 Wild Life Protection Act, 1972 Public Liability Insurance Act, 1991, etc.
________________________________________WATER POLLUTION ACT______________________________________ The objective of the Water Prevention and Control of Pollution Act was to provide for the prevention and control of water pollution and maintaining or restoring of wholesomeness of water for the establishment with a view to carrying out the purpose aforesaid, of boards for the prevention and functions relating thereto and for matters connected therewith. Functions of Central Board
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// ENGINEERING
According to section 2(a) of Environmental Protection Act (1986), ‘Environment’ includes, (i) water, air and land, (ii) the interrelationship which exists among and between, (a) water, air and land and (b) human beings, other living creatures, plants, micro-organisms and property.
AND
Definition of Environment under Indian Law
SCIENCE
Article 21 read as, “No person shall be deprived of his life or personal liberty except according to procedure established by law”.
ENVIRONMENTAL
Environmental protection has been made a fundamental duty of every citizen of this country under article 51-A(g) which read as “it shall be the duty of every citizen of India to protect and improve the natural environment including forests, lakes, rivers and wild life and to have compassion for living creatures”.
D.PARTHIBAN
Constitution of India has a number of provisions demarcating the responsibility of the central and state government towards ‘Environmental Protection’. The state’s responsibility has been laid down under article 48-A which reads as follows, “the state shall endeavor to protect and improve the environment and safeguard the forests and wildlife of the country”.
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Promote cleanliness of streams and wells in different areas of the state. Advise the central government on any matter concerning the prevention and control of water pollution Co-ordinate the activity of the state boards and resolve disputes among them. Provide technical assistance and guidance to the state board, carryout and sponsor investigations and research relating to problems of water pollution. Organize through mass media, a comprehensive programme regarding the prevention and control of water pollution. Collect, compile and publish technical and statistical data relating to water pollution and the measure devised for its effective prevention and control and prepare manuals, codes regarding the treatment and disposal of sewage and trade effluents. Establish and recognize a laboratory to enable the board to perform its functions under this section effectively, including the analysis of samples of water from any stream or well of samples of any sewage or trade effluents.
Functions of State Board
abatement of water pollution. To encourage, conduct and participate the investigations and research relating to problems of water pollution. To collaborate with central board in organizing the training of persons engaged in programmes relating to water pollution, prevention, abatement and treatment. To inspect effluent treatment plants trade waste and domestic waste.
To lay down, modify standard for trade and domestic wastes. To evolve economical and reliable methods of treatments, utilization of treated effluent for
agriculture and disposal into land. To lay down standards of treatment of sewage and trade effluents to be discharged into a stream during dry weather flow.
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water pollution
To collect and disseminate information relating to water pollution, prevention, control or
ENGINEERING
To advise the state government on any matter concerning the prevention, control or abatement of
AND
stream and wells in the state and to secure the execution there of.
D.PARTHIBAN
To plan a comprehensive programme for the prevention, control or abatement of pollution of
Importance of Section 24 of Water Act, 1974 No person should knowingly cause or permit any poisonous, noxious or polluting matter determined in accordance with such standards as may be laid down by the state board to enter into any stream or well or sewer or on land. However, a person shall not be party of an offence under subsection (1), by reason only of having done or could to be done by any of the following acts namely;
Constructing bridge, weir, dam, sluice, dock, pier, drain or sewer or other permanent works which he has a right to construct, improve or maintain.
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ENVIRONMENTAL
likely to pollute a steam or well.
SCIENCE
To advise state government with respect to the location of any industry the carrying on which is
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Depositing any material on the bank or in the bed of any stream for the purpose of reclaiming land or for supporting repairing or protecting the bank or bed of such stream provided such materials are not capable of polluting such streams. Polluting into any stream by any sand or gravel or other natural deposit which has flowed from or been deposited by the current of such stream.
Whoever contravention of provisions of section (24) shall be punishable with imprisonment upto six years and with fine. Even the municipality corporation, companies, government departments also be prosecuted under water act. Varieties of powers are given to the central / state boards to make application to courts for restrains apprehended pollution of water in streams and wells. _________________AIR (PREVENTION AND CONTROL OF POLLUTION) ACT, 1981___________________
The objective of the Act is to provide for the prevention, control and abatement of air pollution for the establishment with a view to carrying out the aforesaid purpose of boards for conferring on and assigning to such boards powers and functions relating there and for matters connected therewith. Functions of Central Board
Importance of Various Section of Air Act Section 19 – Declaration of air pollution control area Section 10 – Lays down the standards for emission of air pollutants from automobiles
AND
Advice to central government on any matter related to air quality To execute nation wide awareness programme Co-ordinate with state boards and resolve disputes among them To provide technical assistance and guidance to state boards Sponsor research and investigation regarding problem of air pollution Collect technical and statistical data to prepare manuals, code, and guide related to air. To lay down standards for the quality of air.
SCIENCE
ENGINEERING
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The main function of the central board as specified in Section 16 of the act shall be to improve the quality of air and to prevent, control or abate air pollution in the country.
D.PARTHIBAN
‘Air Pollution’ means the presence in the atmosphere of any air pollutant. Air pollution means any solid, liquid or gaseous substances (including noise) present in the atmosphere in such concentration as may be or tend to be injurious to human beings or other living creatures or plants or property or environment.
Whoever contravenes any of the provisions of this act or any order or direction issued there under for which no penalty has been elsewhere provided in this act shall be punishable with imprisonment for a term which may extend to 3 month or with a fine extend to Rs. 10,000/- or with both.
Both companies and government departments are also prosecuted under the Air Act. No court shall take cognizance of any offence except on a complaint made by any person who has given notice of not less than 60 days, in the manner prescribed of the alleged offence and his intention to make a complaint to the board.
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ENVIRONMENTAL
Penalty for Contravention of Certain Provision of the Act
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________________________ ENVIRONMENTAL PROTECTION ACT, 1986 (EPA) ___________________________ Terms like ‘Environment’, environmental pollutants, environmental pollution and hazardous substance defined under EPA 1986. (a) (b) (c) (d)
‘Environment’ includes water, air and land and the interrelationship which exists among and between them and human beings, other living creature, plants, micro-organisms and property. ‘Environmental Pollutant’ means any solid, liquid or gaseous substances present in such concentration as may be or tend to be injurious to environment. ‘Environment Pollution’ means the presence in the environment of any environmental pollutants. ‘Hazardous Substance’ means any substance or preparation which by reason of its chemical or physico-chemical properties or handling is liable to cause harm to human beings, other living creatures, plants, micro-organisms, property of the environment.
General Powers of the Central Government under EPA
Section 4 – Appointment of officers and their powers and functions Section 5 – Power to give directions Section 6 – Rules to regulate environmental pollution Under EPA pollution of land and soil is also covered. Penalties for violation under EPA are also listed. Companies and government may also be prosecuted under EPA.
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// ENGINEERING AND SCIENCE
Co-ordination of actions by the state government officers. Planning and execution of nation wide programme on ‘Environmental Pollution’. Laying down standards for emissions or discharge of environmental pollutants from various sources whatsoever. Laying down procedures and safeguards for the prevention of accidents which may cause environmental pollution. Laying down procedures to safeguard hazardous substances. Examination of such manufacturing process, materials and substances as are likely to cause environmental pollution. Carrying out and sponsoring investigation and research. Inspection of the premises, plants, equipment, machinery, manufacturing or other processes, material or substances. Establishment or recognition of environmental laboratories and institutions to carryout function entrusted to them. Preparation of manuals, codes, guides, etc.
ENVIRONMENTAL
In particular and without prejudice to the generality of the provisions of sub-section (1) such measures may include measures with respect to all or any of the following matters.
D.PARTHIBAN
Subject to the provisions of the act, the central government shall have power to take all such measures as it seems necessary or expedient for the purpose of protecting and improving the quality of the environmental pollution.
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____________________________ THE FORESTS CONSERVATION ACT, 1980 _____________________________ ‘Non Forest Purpose’ means the breaking up or cleaning of any forest, land or portion thereof for the cultivation of tea, coffee, spices, rubber, palms, oil bearing plants, horticultural crops, medicinal plants or plantation crops. It is well known that breaking up the soil or clearing of the forest land affects seriously reforestation or regeneration of forests and therefore, such breaking up of soil can only be permitted after taking into consideration all aspects of the question, the over all advantages and disadvantages to the economy of the country. Environmental conditions, ecological imbalance that is likely to occur, its effects on the flora and the fauna in the area, etc., it was therefore thought that the entire control of the forest areas should vest in the central government. With that end in view, Section 2 provided that prior approval of the central government should be obtained before permitting the use of the forest land for non-forest purposes.
3)
Forest (Conservation) Act, 1980 with Amendments Made in 1988 An Act to provide for the conservation of forests and for matters connected therewith or ancillary or incidental thereto. Be it enacted by Parliament in the Thirty-first Year of the Republic of India as follows:1. Short title, extent and commencement.
This Act may be called the Forest (Conservation) Act, 1980. It extends to the whole of India except the State of Jammu and Kashmir.
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2)
The state government may, by notification in the Official Gazette, regulate or prohibit in any forest or wasteland. The state government may, for any, such purpose, construct on its own expense, in or upon any forest or wasteland, such work on it thinks fit. No notification shall be made under subsection (1) nor shall any work begun under subsection (2) until after the issue of notice to the owner of such forest or land calling on him to show cause, within a reasonable period to be specified in such notice, why such notification shall not be made or work constructed, as the case may be and until such objections, if any and any evidence he may produce in support of the same, have been heard by an officer duly appointed for that purpose and have been considered by the state government.
SCIENCE
1)
ENVIRONMENTAL
Section 35 – Protection of Forests for Special Purposes
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(a) The state government may by notification in the office declare the provisions of their chapter applicable to any forest land or wasteland which is not included in a reserve forest, but which is the property of the government. (b) The forest land and waste land included in any such notification shall be called a ‘Protected Forest’. (c) No such notification shall be made unless the nature and extent of the rights of government and of private persons in or over the forest land or wasteland comprised therein have been inquired into and recorded at a survey or settlement, or in such other manner as the state government thinks sufficient.
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Current Requirements that should be met before declaring an area into a Wild Life Sanctuary / National Park under Forest Act
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It shall be deemed to have come into force on the 25th day of October, 1980.
2. Restriction on the dereservation of forests or use of forest land for non-forest purpose. Notwithstanding anything contained in any other law for the time being in force in a State, no State Government or other authority shall make, except with the prior approval of the Central Government, any order directing-
that any reserved forest (within the meaning of the expression "reserved forest" in any law for the time being in force in that State) or any portion thereof, shall cease to be reserved;
that any forest land or any portion thereof may be used for any non-forest purpose;
that any forest land or any portion thereof may be cleared of trees which have grown naturally in that land or portion, for the purpose of using it for reafforestation.
The Central Government may constitute a Committee consisting of such number of persons as h may deem fit to advise that Government with regard to(i) the grant of approval. under Section 2; and (ii) any other matter connected with the conservation of forests which may be referred to h by the Central Government. 3A. Penalty for contravention of the provisions of the Act. Whoever contravenes or abets the contravention of any of the provisions of Section 2, shall be punishable with simple imprisonment for a period which may extend to fifteen days. 3B. Offences by the Authorities and Government Departments. (1) Where any offence under this Act has been committed -
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3. Constitution of Advisory Committee.
AND
(b) any purpose other than reafforestation;but does not include any work relating or ancillary to conservation, development and management of forests and wildlife, namely, the establishment of check-posts, fire lines, wireless communications and construction of fencing, bridges and culverts, dams, waterholes, trench marks, boundary marks, pipelines or other like purposes.
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(a) the cultivation of tea, coffee, spices, rubber, palms, oil-bearing plants, horticultural crops or medicinal plants;
ENVIRONMENTAL
Explanation - For the porpose of this section, "non-forest purpose" means the breaking up or clearing of any forest land or portion thereof for-
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that any forest land or any portion thereof may be assigned by way of lease or otherwise to any private person or to any authority, corporation, agency or any other organisation not owned, managed or controlled by Government;
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(a) by any department of Government, the head of the department; or (b) by any authority, every person who, at the time the offence was committed, was directly in charge of, and was responsible to, the authority for the conduct of the business of the authority as well as the authority; shall be deemed to be guilty of the offence and shall be liable to be proceeded against and punished accordingly:
5. Repeal and saving. (1) The Forest (Conservation) Ordinance, 1980 is hereby replaced. (2) Notwithstanding such repeal, anything done or any action taken under the provisions of the said Ordinance shall be deemed to have been done or taken under the corresponding provisions of this Act.
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(2) Every rule made under this Act shall be laid, as soon as may be after it is made, before each House of Parliament, while it is in session, for a total period of thirty days which may be comprised in one session or in two or more successive sessions, and if, before the expiry of the session immediately following the session or the successive sessions aforesaid, both Houses agree in making any modification in the rule or both Houses agree that the rule should not be made, the rule shall thereafter have effect only in such modified form or be of no effect, as the case may be; so, however, that any such modification or annulment shall be without prejudice to the validity of anything previously done under that rule.
AND
(1) The Central Government may, by notification in the Official Gazette, makes rules for carrying out the provisions of this Act.
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4. Power to make rules.
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(2) Notwithstanding anything contained in sub-section (1), where an offence punishable under the Act has been committed by a department of Government or any authority referred to in clause (b) of sub-section (1) and it is proved that the offence has been committed with the consent or connivance of; or is attributable to any neglect on the part of any officer, other than the head of the department, or in the case of an authority, any person other than the persons referred to in clause (b) of sub-section (1), such officer or persons shall also be deemed to be guilty of that offence and shall be liable to be proceeded against and punished accordingly.
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Provided that nothing contained in this sub-section shall render the head of the department or any person referred to in clause (b), liable to any punishment if he proves that the offence was committed without his knowledge or that he exercised all due diligence to prevent the commission of such offence.
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________________________________WILD LIFE PROTECTION ACT________________________________ 38A. Constitution of Central Authority
(1)
The Central Government shall constitute a body to be known as the Central Zoo Authority (hereinafter in this Chapter referred to as the Authority), to exercise the powers conferred on, and to perform the functions assigned to it under this Act.
(2)
The Authority shall consist of: (a)
Chairperson
(b)
such number of members not exceeding ten and Member-Secretary
(c)
38B. Term of office and conditions of service of chairperson and members etc. The chairperson and every member other than the member-secretary shall hold office for such period, not exceeding three years, as may be specified by the Central Government in this behalf..
(2)
The chairperson or a member may, by writing under this hand, addressed to the Central Government, resign from the office of chairperson or, as the case may be, of the Member.
(3)
The Central Government shall remove a person from the office of chairperson or member referred to in sub-section (2) if that person:
(c) becomes of unsound mind and stands so declared by a competent court. (d) refuses to act or becomes incapable of acting. (e) is, without obtaining leave or absence from the authority, absent from three consecutive meetings of the Authority. or (f) in the opinion of the Central Government has so abused the position of chairperson or member as to render that person's continuance in office detrimental to the public interest. Provided that no person shall be removed under this clause unless that person had been given a reasonable opportunity of being heard in the matter.
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AND SCIENCE
(b) gets convicted and sentenced to imprisonment for an offence which, in the opinion of the Central Government, involves moral turpitude.
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(a) becomes an undischarged in solvent
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(1)
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to be appointed by the Central Government.
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(4)
A vacancy caused under sub-section (2) or otherwise shall be filled by fresh appointment.
(5)
The salaries and allowances and other conditions of appointment of chairperson, members and Member-Secretary of the Authority shall be such as may be prescribed.
(6)
The Authority shall, with the previous sanction of the Central Government, employ such officer and other employees as it deems necessary to carry out the purposes of the Authority.
(7)
The terms and conditions of service of the officers and other employees of the authority shall be such as may be prescribed.
(8)
No act or proceeding of the Authority shall be questioned or shall be invalid on the ground merely of the existence of any vacancies or defect in the constitution of the Authority.
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The Authority shall perform the following functions, namely: (a) specify the minimum standards for housing, upkeep and veterinary care of the animals kept in a zoo.
(d) identify endangered species of wild animals for purposes of captive breeding and assigning responsibility in this regard to a zoo. (e) co-ordinate the acquisition, exchange and loaning of animals for breeding purposes.
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(f) ensure maintenance of stud books of endangered species of wild animals bred in captivity.
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(c) recognise or derecognize zoos;
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(b) evaluate and assess the functioning of zoos with respect to the standards or the norms as may be prescribed.
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38C. Functions of the Authority
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ۼ܃۷ ܂െ ǣ ۶ۼۯۻ܃ ۶܂ۯۺ܃۾۽۾ۼۯۻ܃۷ۼۯۼ۽۲۳܄ۼ۷ۻۼ۽܀۳܂ۼ
POPULATION GROWTH POPULATION VARIATION AMONG NATIONS HUMAN RIGHTS FAMILY WELFARE PROGRAMME WOMEN AND CHILD WELFARE
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ENVIRONMENTAL
CHAPTER-V PROVIDES INFORMATION ON:
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UNIT – 5 HUMAN POPULATION AND THE ENVIRONMEN
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→ → → → → → → →
HUMAN RIGHTS Human rights day is celebrated on 10th December of every year Every individuals of India has the following rights: → →
Human rights to Freedom Human rights to Property
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→ → → →
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India launched the national family welfare programme in 1951. India started family planning programme in the year of 1952. Indian government forced family planning campaign all over the nation in the year of 1970 The minimum age of marriage is increased from 18 to 21and from 15 to 18 for men and women respectively The objective of the programme is to reducing the birth rate to extent necessary to stabilize the population at a consistent level with the requirement of the national economy. Strict implementation of family planning will help to reduce human population Mass media like television, radio, etc can be used for canvassing the people to adopt birth control methods Campaign should be launched to promote small family concept. We should encourage “one child for one couple concept” Efficient management of public health is needed to control population The demographic scenario of Tamilnadu as per government of India sample registration 2000 Birth rate = 19.3/1000 population Death rate = 7.9/1000 population Infant mortality = 51/1000 The following demographic goals have been fixed to be achieved by the year 2008(tenth five year plan) Infant mortality rate = 30/1000 live birth Birth rate = 15/1000 population Infrastructure facilities in the government hospitals and health care center must be improved. Achieving 100 % registration of birth, death .pregnancy and marriage Encouraging late marriage and late child-bearing. Encouraging breast feeding. Constraining the spreading of AIDS/HIV Prevent and control of communical diseases. Providing free education to all children up to the age 14. Improving women’s health and education.
ENVIRONMENTAL
→ → → →
D.PARTHIBAN
FAMILY WELFARE PROGRAMME/FAMILY PLANNING PROGRAMME
Page: to to to to to to to to to to
Freedom of religion Culture and civilization Education Equality find Solution to exploitation Food and shelter health employment social security form trades and companies
HUMAN POPULATION Every second, 4 or 5 children are born somewhere on the earth and 2 people die. Difference between birth and death is nearly 2.5.it means that there is the increase of 2.5 humans/every huma second. Over population will definitely cause natural resources depletion and environmental degradation.
Crude birth rate: the number of births/1000 persons in a year. Total fertility rate: the number of children born to an average woman in a population popu during her whole reproductive period.
The highest recorded total fertility is 12 children per women (in north America) Zero population growth: it is the situation in which birth + immigration is equal to death +
ENVIRONMENTAL
SCIENCE
AND
emigration. Crude death rate: the number of deaths per 1000 persons in any given year.
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rights rights rights rights rights rights rights rights rights rights
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Human Human Human Human Human Human Human Human Human Human
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→ → → → → → → → → →
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Life expectancy: it is average age of a person at death. Current average life expectancy is around
Our distant ancestors lived a precarious existence as hunters and gatherers. This way of life kept their total numbers small ( 55,000 villages * India was the first country in the world to start family planning. Poverty, low literacy and education levels among women, lack of consistent support from government, poor planning and bureaucratic ratic inefficiency are some of the reasons why family planning programme has not been a big success.
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Population growth and urbanization will place a greater pressure on natural resources, but there are eco-friendly iendly alternatives that could mitigate the problem to certain extent. Rapid population growth will overstress the earth’s natural resources and crowd out undomesticated plant and animal species. All people want to be fed, clothed, housed and have ac access cess to clean water. To meet these requirements, water, land, forest and other natural resources must be exploited to some degree. As population increases, more resources are needed to meet the basic requirements. More forest must be cut down to pro provide vide wood for housing and fuel. More cleared land is needed for agriculture and development. All of these are finite. More than 99% of the world’s food supply comes from the land, while less than 1% from oceans and other aquatic habitats. The continued ued production of an adequate food supply is directly depended an ample fertile land, fresh water, energy, plus the maintenance of biodiversity. As the human population grows, the requirements for these resources also grow. .
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D.PARTHIBAN
Environmental Implications of Population Growth
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The Human Population
TEN MOST POPULOUS COUNTRIES MOST POPULOUS NATIONS(in MOST POPULOUS NATIONS(in 2000) 2050) COUNTRY CHINA INDIA USA INDONESIA BRAZIL
POPULATION (MILLIONS)
COUNTRY
POPULATION (MILLIONS)
1265
INDIA
1628
1002
CHINA
1369
281
USA
404
212
INDONESIA
312
170
NIGERIA
304
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At the same time as people consume these resources, they produce waste that is put back into the air, land and water. The greater amount of waste from larger populations put more stress on ecosystems. It is true that the highest population growth rates are found the developing countries. However, because affluent countries consume more resources, they remain the primary contributors to certain global environmental problems like global warming. The G7 nations, the US, Canada, Britain, France, Germany, Japan and Italy represents only 10% of global population but consumes 40% of fossil fuels as well as forest commodities. Because consumption rates are so high in these countries, even small increase in population can have a significant impact. Water is critical for all crops which require large amount of water during their growing season. For example, a hectare of corn will require more than 5 million litres of water during one growing season. This means that more than 8 million litres of water per hectare must reach the crop. In total, agricultural production consumes more fresh water by agriculture. Competition for water resources among individuals, regions and countries is already occurring with the current world population. In China, where more than 300 cities already short of water, these shortages are intensifying. Water resources, are under great stress as populous cities, states and countries require and withdraw more water from rivers, lakes and aquifers. Every year, a major threat to maintaining future water supplies is the continuing over-draft of surface and groundwater resources. Fossil energy is another prime resource used for food production. Nearly 80% of the world’s fossil energy used each year is used by the developed countries and part is expended in producing high animal protein diets. The intensive farming technologies of developed countries use massive amounts of fossil energy for fertilizer, pesticides, irrigation, etc., as a substitute for human labour. In general, developing countries have been relying heavily on fossil energy, especially for fertilizers and irrigation to augment their food supply.
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ENVIRONMENTAL
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PAKISTAN RUSSIA BANGLADESH JAPAN NIGERIA
151
PAKISTAN
285
145
BRAZIL
244
128
BANGLADESH
211
127
ETHIOPIA
188
123
CONGO
182
210
Every 3 years, the global environment must support another 285 million pe people. ople.
By 1850, the human population was one billion. By 1930, it was 2 billion. It took 10,000 generations to reach 2 billion. The human population is now growing at a rate of about 3 people/second or 260 thousand/day or 1.8 million per week or 93 million/year Even the U.S. population is growing fast. We're currently adding the equivalent of three Washington, D.C.s every year; another New Jersey every 4 years.
As a result of this rapid growth:
Approximately 1.3 billion of the world's people are impoverished, living on the equivalent of less than 1 dollar a day. And as population steadily increases, the gap between rich and poor is widening.
Some 60% of the 4.8 billion people in developing count countries ries lack basic sanitation, and almost oneone third have no access to clean water.
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2,000 years ago the estimated human population was 150 million
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ENVIRONMENTAL
Human Population facts:
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Human Population History:
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Nearly 1 billion people in the world are illiterate, two-thirds of them women.
Despite increases in grain production that began in the 1950s, thanks to "miracle wheat" and other advances in agricultural technology, such increases seem to have leveled off in recent years. Some 841 million people today are chronically malnourished, and there are 88 "food deficit" countries. This means "they can neither feed themselves nor afford the imports they need," according to the United Nations Population Fund, a subsidiary of the UN General Assembly and the largest internationally-funded source of population assistance to developing countries.
Supplies of water for irrigation are declining around the world as underground water reserves aquifers - become depleted faster than nature can fill them. Groundwater overdrafting is now widespread in the crop-producing regions of central and northern China, northwest and southern India, parts of Pakistan, much of the Western United States, North Africa, the Middle East, and the Arabian Peninsula.
Nearly half the earth's land mass already has been changed by human activity - wetlands filled in, forests cut down, prairies plowed under. Runoff from farms, industries, and urban areas has resulted in some 50 "dead zones" in coastal waters.
Among the ocean's 200 major fish stocks, 35% are in decline, and another 25% are being fully exploited.
Species are going extinct at a faster rate than ever before, including the time when dinosaurs were dying out.
Factors Contributing to the Population Explosion:
The green revolution Agricultural advances have insured that no one has to starve. For thousands of years, the Earth's carrying capacity depended on the available food supply. That is no longer the case.
Advances in medicine
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Disease has throughout history always been the definitive factor in the limiting of the human population. However, medical research has largely controlled (or eliminated) such diseases as smallpox, malaria, & cholera. As a result, death rates have declined dramatically.
LIFE EXPECTANCY( in Years)
USA
22.6
23.3
60.3
60.5
42.4
43.7
77.4
84.2
30.9
33.0
61.7
73.6
56.6
59.5
77.0
82.1
45.6
48.3
74.7
79.3
The industrial revolution An increase in the availability and use of technology has lead to a more densely packed society that attempts to make room for an ever increasing population. The influx of new technology into the global market over the past 150 years has made life generally easier in the industrialized nations of the world and led to promising social situations that provoke the tendency of people to have more children.
Other factors: o In some countries people lack awareness of birth control or the ability to limit the size of their families. Recent United Nations statistics indicate that 90% of women in 10 African nations had not heard of contraception. o People in some developing countries who do want to limit the growth of their families lack access to contraception or reproductive-health services. Family planning methods are simply not available in large sections of the world. As many as 500 million women in developing countries live too far from health centers to obtain contraceptives, & unsafe abortions kill an estimated 70,000 women a year. o Human reproduction is a matter of great religious and cultural importance as well. The religious teachings of many people prohibit or discourage contraception. And some cultures traditionally value large families as a sign of prestige and power.
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SWEDEN
FEMALES
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RUSSIA
MALES
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JAPAN
FEMALES
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INDIA
MALES
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NATION
2000
ENVIRONMENTAL
1900
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Population growth: The overall rate of population increase depends on the number of births and deaths, but also on the length of generations -- the age at which women have their first baby. o For example, if all women had three kids with a 15 15-year year average generation time, the rate of population growth would be 2.7%. If the average spacing were 30 years, the growth would drop in half -- to 1.35%. o How does percent population growth translate into 'doubling times?'
5000 B.C 800 B.C 200 B.C A.D 1200 A.D 1700 A.D 1900 A.D 1965 A.D 1990
POPULATION
DOUBLING TIME
50 MILLION
--
100 MILLION
4200 Yrs
200 MILLION
600 Yrs
400 MILLION
1400 Yrs
800 MILLION
500 Yrs
1600 MILLION
200 Yrs
3200 MILLION
65 Yrs
5300 MILLION
38 Yrs
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SCIENCE
YEAR
ENVIRONMENTAL
HISTORY WORLD POPULATION & DOUBLING TIME
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A.D 2020(EXPECTED)
8230 MILLION
214
55 Yrs
Fertility Rates:
Replacement-level level fertility = the number of children a couple must bear to replace themselves o slightly more than 2 children because some children die before reaching their reproductive years o reproducing at this level does NOT mean that population growth stops; there are so many "future parents" already alive that, even at replacement replacement-level, level, population will continue to grow for many years
Total fertility rate (TFR) - estimate of the average nu number mber of children a woman will have during childbearing years o In 1995, the TFR was 3.1 children per woman ; still far above replacement level
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// ENGINEERING AND
SCIENCE
fertility rate) can be below replacement level while the population continues to grow, if there are a disproportionately large number of couples in these younger age groups. That is the situation in Kenya and, to a lesser degree, the United States. The age structure of the population, then, is also an important factor in population change (see the population pyramids for Kenya, Sweden, & the U.S. above). When a substantial proportion of a country's population is young, high population growth rates in a country are to be expected, even if the average TFR is modest. The reason is that so many females are of childbearing age, that even a modest average TFR results in a large number of births
ENVIRONMENTAL
Birth and death rates do not tell the whole story of population growth. A country's TFR (total
D.PARTHIBAN
Population Age Structure:
215
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This map shows the average number of children born to a woman during her lifetime. The darker the color, the greater the number of children. For example, France at 1.7 children has a lower fertility rate than Egypt at 3.6 children. The total fertility rate (TFR) is the average number of children a woman would have, assuming that current age-specific birth rates will remain constant throughout her childbearing ears (usually considered to be ages 15-49).
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Earth's Carrying Capacity (is the Earth overpopulated?):
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Carrying capacity is the number of organisms an environment (e.g., the Earth) can support o determined by: food production, living space, waste assimilation, & resource availability o for humans, carrying capacity can be expanded through advances in agriculture, industry, & medicine
Some believe Earth's carrying capacity has already been exceeded as illustrated by: o polluted air o depleted fisheries The world's marine catch has increased more than four times in the past 40 years -- from 18.5 million tons in 1950 to 82.5 million tons by 1992. This staggering growth has resulted in overfishing and wasteful, destructive fishing practices worldwide which now threaten the lives of hundreds of millions of people who are vitally dependent on fishing for food and livelihoods. They face resource depletion, competition from industrial and distant water fleets, and loss of access to traditional marine food supplies. deforestation Continued forest loss and degradation will have serious implications at local, regional, and global levels. Exploitation and clearance of natural forests are destroying the environment and way of life for tens of thousands of indigenous people. Disappearing forest cover also represents incalculable losses in biological diversity and ecological services, including nutrient recycling, watershed management, and climate regulation.
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o
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species extinction
o o
denuded landscapes global warming
o o o
starvation poverty and so on
Others are more optimistic & believe Earth could support many more people o More people = more productivity = more knowledge = better production methods + discovery of new substitutes, and so on
Impacts of continued growth in human populations include:
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ENVIRONMENTAL
SCIENCE
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ENGINEERING
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increased hunger/starvation while food production levels off or even declines (i.e., less food/person)
increasing desertification o Desertification is the conversion of productive rangeland or cropland into desertlike land. It is usually caused by a combination of overgrazing, soil erosion, prolonged drought and climate change.
increased number of refugees
Emerging diseases
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SCIENCE
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TOP 10 LARGEST URBAN CITIES IN THE WORLD NAME OF THE CITY POPULATION IN MILLION TOKYO 28.8 MEXICO CITY 17.8 SAO PAULO,BRAZIL 17.5 MUMBAI,INDIA 17.4 NEW YORK,AMERICA 16.5 SHANGHAI.CHINA 14.0 LOS ANGELES 13.0 LAGOS,NIGERIA 12.8 CALCUTTA,INDIA 12.7 BUENOS AIRES 12.3
ENGINEERING
S.NO 1 2 3 4 5 6 7 8 9 10
D.PARTHIBAN
increased urbanization o Cities may offer opportunities for the people of developing countries. However, the danger lies in the structural inadequacies typical of many cities in these countries. The most obvious of these inadequacies are those of public sanitation. Insufficient or non-existent sewage systems in exist in many parts of these cities. Water supplies can thereby become polluted, leading to the high incidences of disease.
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dying seas & rivers, for example: o Colorado River
Projected population (millions) 2050
Infant martality Rate
Total fertilit y Rate
% of population of age , 15
World
7,818
9,036
56
2.8
30
More developed
1,248
1,242
8
1.6
18
Less developed
6,570
7,794
61
3.2
33
India
1,363
1,628
70
3.2
36
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ENVIRONMENTAL
SCIENCE
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Projected population (millions) 2025
ENGINEERING
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ROLE OF NGO ORGANISATION
Creating awareness among people on current environmental issues and their solutions. Being involved in the protection of human right to have a clean environment. Conducting participatory rural appraisal. Transferring information through newsletter, brochures, articles, audiovisuals, etc. Helping the village administrative officials in the preparation, application and execution of projects on environmental protection.
There are more than 10,000 NGO’s in India ranging from National Agencies to local groups. The Ministry of Environment and Forests (MOEF) is increasingly extending support to NGO activity and routing many of its own programme through them.
Until recently Indian women stood for a significant tradition and culture since the Vedic age. However, they are suppressed, neglected and harassed due to gender discrimination. They suffer from malnutrition, education, etc. They are underpaid. Women suffered all sorts of abuse by men.
ENVIRONMENTAL
SCIENCE
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Now the government has revealed that progress cannot be achieved without adopting women welfare programmes specially women education. So special care (reservations and incentives) has been taken to provide education, health, job and other facilities to women.
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WOMEN EDUCATION
ENGINEERING
The Environmental Ministry has been organizing National Environmental Awareness Campaigns (NEAC), every year in order to spread the messages of environmental conservation across society. Each year’s campaign has a specific theme. The district level programme called Paryavaran Vahini was launched to promote and support for Environmental Legislation in order to ensure compliance.
D.PARTHIBAN
ENVIRONMENTAL EDUCATION
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___________________________________QUESTION BANK________________________________
UNIT 1: INTRODUCTION TO ENVIRONMENTAL STUDIES AND NATURAL RESOURCES
QUESTIONS - Part B 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.
Explain briefly the structure of the atmosphere. (Dec. 05) Discuss in detail the economic importance of forests. What are the major causes of deforestation? Discuss its consequences. (Dec. 05) Discuss the ill effects of deforestation. (Dec. 05) Discuss in detail the ecological services provided by forests. Mention the various effects of timber extraction. What problems are caused by the over-exploitation of water resources? Explain the effects of deforestation and over utilization of ground water. (June 05) Explain in detail the various benefits and problems associated with the construction of dams. Discuss in detail the various environmental impacts of mining. Write short notes on: a) shifting cultivation b) eutrophication Discuss the problems associated with modern agriculture with respect to fertilizers and pesticides. Discuss any two renewable energy sources in detail.
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Define environmental science. (Dec. 05) Explain biosphere. (Dec. 05) What role does the lithosphere play in the environment? Mention the various functions of the atmosphere. Mention the various subdivisions of the biotic and abiotic components of the environment. What are the conventional sources of energy for mankind? (Dec. 05) Give two examples each of renewable and non-renewable resources. Classify natural resources with suitable examples. State the problems caused by the construction of dams. (Dec. 05) Mention four minor forest products. Define sustainable forestry. (Dec. 05) What are the various causes of deforestation? What are the effects of timber extraction? Mention the various commodities and environmental services provided by forests. Mention four effects of deforestation. Mention the problems associated with traditional agriculture. Mention the main sources of food, with an example each. Mention the problems associated with overexploitation of water resources. Mention four effects of mining. State the environmental effects of extracting and using mineral resources. (June 05) Under what conditions do we encounter land subsidence? Mention the various causes for soil erosion. Classify energy resources with suitable examples. What is geothermal energy? (Dec. 05) State the need for public awareness for solving environmental problems. (June 05)
ENVIRONMENTAL
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25.
D.PARTHIBAN
QUESTIONS - Part A
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Explain briefly the various methods of harvesting solar energy. (June 05) Write a note on tidal power. (June 05) Discuss in detail the role of an individual in conservation of natural resources. (Dec. 05) What are the measures recommended for conservation of natural resources? (June 05) UNIT 2: ECOSYSTEMS AND BIODIVERSITY
QUESTIONS - Part B
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Define ecosystem. Give two examples. Give the classification of ecosystems with suitable examples. Define producers. (Dec. 05) What are chemo autotrophs? Give an example. What are consumers? Give the classification of consumers with examples. What are decomposers? Give two examples. What is the role played by decomposers? Define food chain. Give two examples of simple food chains. What are the types of food chains? Give an example for each type. Why do we find food webs in nature rather than simple food chains? Define trophic level. Assign trophic levels to producers and various types of consumers. Justify: A given species may occupy more than one trophic level depending on its food source. Define food web. Give an example. Discuss the importance of food webs with a suitable example. Mention the various types of ecological pyramids. The pyramid of energy flow always takes a true upright shape. Why? Define ecological efficiency. Define pyramid of numbers with a suitable example. Define pyramid of biomass with a suitable example. What is ecological succession? (June 05) Distinguish between primary succession and secondary succession. What is a climax community? What are the various functions of an ecosystem? Define primary productivity of an ecosystem. What is meant by secondary production? Name the four ecosystems. (Dec. 05) Mention three types of forests. Mention the various biotic components of the forest ecosystem with examples. Mention the various types of grassland ecosystems. What are the characteristics of the desert ecosystem? Define biodiversity. (Dec. 05) What is biodiversity and what is its significance? (June 05) Enumerate the human activities which destroy the biodiversity. (Dec. 05) Define: hot spots of biodiversity. Which are the two hot spots in India? Explain threatened and endangered species. (Dec. 05) What are rare and endangered species? Give relevant examples in the Indian environment. (May 05) Name two wildlife sanctuaries if India. Name the species protected and the state in which it is located.
ENVIRONMENTAL
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39.
D.PARTHIBAN
QUESTIONS - Part A
8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20.
UNIT 3: ENVIRONMENTAL POLLUTION
D.PARTHIBAN
4. 5. 6. 7.
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2. 3.
What is an ecosystem? Describe the structure and function of various components of an ecosystem. (Dec. 05) Define food chains. Name and explain the various types of food chains with suitable examples. Depict diagrammatically a terrestrial food web in an ecosystem. How many food chains are there in that food web? Why is the concept of a food web more real ecologically than the concept of a simple food chain? Explain two applications of the pyramid of energy flow. Define ecological succession. Give an account of primary succession. Explain: ecosystem, energy flow in ecosystem, food chain, food webs, and ecological pyramids. (June 05) Explain food chain and food web. (Dec. 05) Write a note on carbon cycle. (Dec. 05) Name and describe the characteristic features of various types of forest ecosystems (biomes). Also describe the structure of the forest ecosystem. Describe the characteristic features and structure of the grassland ecosystem. Where do such ecosystems occur? State the chief characteristic features of a desert ecosystem. Describe the biotic and abiotic components of the desert ecosystem. Describe the biotic and abiotic components of any fresh water ecosystem studied by you. State the biotic and abiotic components of the ocean ecosystem. Describe the types, characteristic features, structure and function of:i) forest ecosystem ii) aquatic ecosystem. (June 05) a) Explain ecosystem. b) Discuss the components of ecosystem. c) Briefly explain the energy flow through ecosystem. (Dec. 05) Discuss the value of biodiversity. Discuss in detail the causes for extinction of species by human actions. a) Discuss the threat faced by Indian biodiversity. B) Discuss the strategy adopted to conserve biodiversity. (Dec. 05) Explain the various threats to biodiversity and the measures recommended for conservation of biodiversity. (June 05)
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Mention three sources of indoor pollution. What is smog? Distinguish between the two types of smog. Define BOD. What are its units? What will be the effect on aquatic ecosystems when high temperature effluents are discharged into it? Define thermal pollution. (Dec. 05) Write any two causes of soil pollution. (Dec. 05) When does a sound cause noise pollution? (Dec. 05) What is eutrophication? (May 05) What is acid rain? (Dec. 05) What is acid deposition? (Dec. 05) List any two air pollutants and their effects on human beings from automobile emission. (May 05) Name any four air pollutants, their sources and effects. (June 05) Name the sources and effects of marine pollution. (June 05) What are the causes and effects of global warming? (June 05)
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ENVIRONMENTAL
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14.
SCIENCE
QUESTIONS - Part A
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15. Give some examples of green house gases? (Dec. 05) 16. What are the causes and effects of ozone layer depletion? (June 05) 17. Name two ozone depleting substances (ODS). (May 05)
10. 11. 12. 13. 14. 15. 16. 17. 18. 19.
UNIT 4: SOCIAL ISSUES AND THE ENVIRONMENT QUESTIONS - Part A Explain the term sustainable development. (Dec. 05) What is acid rain? (Dec. 05) Mention three substances which contribute to the green house effect. List any four pollution control acts. (Dec. 05)
SCIENCE
1. 2. 3. 4.
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6. 7. 8. 9.
ENGINEERING
3. 4. 5.
Give an account of the green house effect. Discuss in detail the importance of the green house effect for human survival. What is the enhanced green house effect? Write short notes on: a) cyclone collectors b) electrostatic precipitators. What are the sources and effects of various air pollutants? Discuss any two control methods. What are the major pollutants of the atmosphere? Enumerate the adverse effects caused by these pollutants. (Dec. 05) What is thermal pollution? Discuss the effects and control methods of thermal pollution. Explain the causes, effects and control measures of water pollution. (June 05) Discuss sewage treatment with a suitable block diagram. What are the various causes and effects of noise pollution? Discuss the control measures for noise pollution. Discuss the various aspects of prevention and control of noise pollution. (Dec. 05) Discuss the causes and effects of soil pollution. How can soil pollution be controlled? What are the causes of soil erosion and the methods of preventing it? (Dec. 05) Define flood. What are its causes? What measures should be taken to mitigate flood disaster? Compare nuclear power with coal power. (Dec. 05) How will you take care of solid wastes generated in urban areas? (Dec. 05) What are the effects of improper municipal solid waste management? State the measures recommended for proper management of the solid wastes. (June 05) Explain the methods of disposal of municipal solid waste. (Dec. 05) Write a note on disposal of radioactive wastes. (Dec. 05) Explain Bhopal gas tragedy. (Dec. 05)
AND
1. 2.
D.PARTHIBAN
QUESTIONS - Part B
1. 2. 3. 4. 5. 6. 7.
What do you mean by sustainable development? What are the measures to be adopted to attain sustainability? Discuss the agenda for sustainable development. (Dec. 05) What is meant by rain water harvesting? Why is it necessary in the present situation? (Dec. 05) Write in detail about global warming. (Dec. 05) Discuss the measures to conserve water. What is rainwater harvesting? What are the purposes served by it? What are the major issues and problems related to rehabilitation of displaced tribes?
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ENVIRONMENTAL
QUESTIONS - Part B
8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25.
Critically discuss the anthropocentric and eco-centric world views. Which view appeals to you more and why? What are greenhouse gases and greenhouse effect? Discuss the potential and contribution of these gases to global warming phenomenon. What are the major implications of enhanced global warming? What are the major impacts of acid rain and how can we control it? Discuss the natural formation and occurrence of ozone in the stratosphere. Which are the agents responsible for ozone depletion? Write a critical note on nuclear holocaust. Discuss various methods for wasteland reclamation. Name the laws that have been framed for environmental protection and mention the objectives for each Act. (Dec. 05) Discuss the salient features of a) Wildlife (Protection) Act, 1972 b) Forest (Conservation) Act, 1980. How do you define pollution as per Water (Prevention and Control of Pollution) Act, 1974? What are the salient features of the Act? State the important provisions in Environmental Protection Act, Air Act and Water Act. (June 05) Discuss briefly on the Indian Environmental Acts. (Dec. 05) Write short notes on: a) environmental ethics b) wasteland reclamation. (June 05) Justify: Greenhouse gases at its natural levels is very essential for life to survive on this earth. What are the effects of ozone layer depletion? Explain the mechanism of ozone layer depletion. (Dec. 05) What is the significance of ozone layer depletion and global warming? What are the pollutants that are responsible and control measures? (Dec. 05) What are the different methods to propagate environmental awareness in the society? Write briefly on the community participation in environment management programmes.
What is population explosion? (Dec. 05) State how environment and human health are related. (Dec. 05) Expand: a) HIV b) AIDS
QUESTIONS - Part B 1. 2. 3. 4. 5. 6. 7.
What is meant by population explosion? Discuss the Indian scenario. Population explosion affects the environment seriously. Discuss. (Dec. 05) Deterioration of environment leads to deterioration of human health. Justify. (Dec. 05) Discuss briefly on the reasons for population explosion. (Dec. 05) Discuss the environmental and social impacts of growing population. (Dec.05) Write briefly on the effect of increasing affluence on environment. (Dec. 05) What do you mean by: a) doubling time b) total fertility rate c) zero population growth d) life expectancy? 8. How can age structure pyramids serve as useful tools for predicting population growth trends of a nation? Explain with examples. 9. Discuss the family welfare programme in the Indian context. 10. What are the objectives and elements of value education? 11. Discuss the various issues and measures for women and child welfare at the national and international levels.
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AND
1. 2. 3.
SCIENCE
QUESTIONS - Part A
ENVIRONMENTAL
UNIT 5: HUMAN POPULATION AND THE ENVIRONMENT
ENGINEERING
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D.PARTHIBAN
12. What is the role of NMIS, ENVIS and GIS in dissemination of environmental information and environmental management? 13. Explain the role of information technology in environment and human health. (June 05) 14. Write a short note on value education. (June 05) 15. Write briefly on the implementation of family planning programme. (Dec. 05) 16. Write a note on AIDS in developing countries. (Dec. 05) 17. Discuss the factors influencing the family size. (Dec. 05)
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