ABSTRACT This experiment is done to determine the heavy metal that present in water sample. The analysis of heavy metals is done to determine the chlorine total, sulfate, chlorine free, phosphorus, iron total and chromium hexavalent. The reagent that used to determined the heavy metal in water sample is depends on what heavy metal that wants to determined. The reagent that used in this experiment for total Chlorine test was Powder Pillow, Sulfa Ver 4 Reagent Powder Pillow for sulfate test, Free Chlorine Powder Pillow for free chlorine test, Phos Ver 3 Phosphate Powder Pillow for phosphorus test, Ferro Ver Iron Reagent Powder Pillow for iron test, and Chroma Ver 3 Reagent Powder Pillow for chromium hexavalent. The sources for chlorine test of heavy metal are generally from industrial, municipal, and urban runoff, which can be harmful to humans and aquatic life and it depends on the types of heavy metal that present in water sample. From this experiment, the chlorine total, chlorine free, phosphorus and iron total seems present in water sample while sulfate and chromium hexavalent have in small quantity since from the result of the changes colour, the chromium hexavalent and sulfate not change the colour with the desired coloured. The water sample that taken from the Section 7 is still safe used for aquatic life since the value of the heavy metal in that water sample is still less than the standard of heavy metal requirement in water quality. In generally, when the excessive of heavy metal is present in water sample, it will affect the human life depends on what types of heavy metal in water sample and for aquatic life they will easily to die because do not have enough oxygen for respiration.
INTRODUCTION The term heavy metal refers to any metallic chemical element that has a relatively high density and is toxic or poisonous at low concentrations. Heavy metals are natural components of the Earth's crust. They cannot be degraded or destroyed. To a small extent they enter our bodies via food, drinking water and air. Heavy metals are dangerous because they tend to bioaccumulate. Bioaccumulation means an increase in the concentration of a chemical in a biological organism over time, compared to the chemical's concentration in the environment. Compounds accumulate in living things any time they are taken up and stored faster than they are broken down (metabolized) or excreted. Heavy metals can enter a water supply by industrial and consumer waste, or even from acidic rain breaking down soils and releasing heavy metals into streams, lakes, rivers, and groundwater. Generally the water pollution is described as the presence in water of enough harmful or objectionable material to damage the water's quality. Water pollution has many sources and characteristics. Humans and other organisms produce bodily wastes which enter rivers, lakes, oceans and other surface waters; Industry is creating new chemicals each year, all of which eventually find their way to water. In high concentrations these wastes result in bacterial contamination and excessive nutrient loading (eutrophication). Inorganic industrial wastes are much tricker to control and potentially more hazardous Industries discharge a variety of toxic compounds and heavy metals, and wastewater from industrial process may also be too hot or too low in dissolved oxygen to support life. Toxic metals can be present in industrial, municipal, and urban runoff, which can be harmful to humans and aquatic life. Increased urbanization and industrialization are to blame for an increased level of trace metals, especially heavy metals, in our waterways. There are over 50 elements that can be classified as heavy metals, 17 of which are considered to be both very toxic and relatively accessible. Toxicity levels depend on the type of metal, it's biological role, and the type of organisms that are exposed to it.
Heavy metals in the environment are caused by air emissions from coalburning plants, smelters, and other industrial facilities; waste incinerators; process wastes from mining and industry; and lead in household plumbing and old house paints. Industry is not totally to blame, as heavy metals can sometimes enter the environment through natural processes. Once released to the environment, metals can remain for decades or centuries, increasing the likelihood of human exposure. In addition to drinking water, we can be exposed to heavy metals through inhalation of air pollutants, exposure to contaminated soils or industrial waste, or consumption of contaminated food. Because of contaminated water, food sources such as vegetables, grains, fruits, fish and shellfish can also become contaminated by accumulating metals from the very soil and water it grows from.
OBJECTIVE The aims of this experiment are to determined the heavy metal that present in the water sample that being used in daily life and to determined the effect of these heavy metals towards living things.
THEORY (A) Free Chlorine Free chlorine is defined as the concentration of residual chlorine in water present as dissolved gas (Cl2), hypochlorous acid (HOCl), and/or hypochlorite ion (OCl-). The three forms of free chlorine exist together in equilibrium. Cl2 + H2O HOCl
HOCl + H+ + ClH+ + OCl-
Combined chlorine Combined chlorine is defined as the residual chlorine existing in water in chemical combination with ammonia or organic amines which can be found in natural or polluted waters. Ammonia is sometimes deliberately added to chlorinated public water supplies to provide inorganic chloramines. (B) Total Chlorine Total chlorine is the sum of free and combined chlorine. When chlorinating most potable water supplies, total chlorine is essentially equal to free chlorine since the concentration of ammonia or organic nitrogen compounds (needed to form combined chlorine) will be very low. When chloramines are present in the municipal water supply, then total chlorine will be higher than free chlorine. (C) Sulfate Sulfate (SO4) can be found in almost all natural water. The origin of most sulfate compounds is the oxidation of sulfite ores, the presence of shales, or the industrial wastes. Sulfate is one of the major dissolved components of rain. High concentrations of sulfate in the water we drink can have a laxative effect when combined with calcium and magnesium, the two most common constituents of hardness. Bacteria, which attack and reduce sulfates, form hydrogen sulfide gas (H2S).
The maximum level of sulfate suggested by the World Health Organization (WHO) in the Guidelines for Drinking-water Quality, set up in Geneva, 1993, is 500 mg/l. EU standards are more recent, 1998, complete and strict than the WHO standards, suggesting a maximum of 250 mg/l of sulfate in water intended for human consumption. (D) Phosphorus
Phosphorus is an important nutrient for plant growth. In aquatic systems, a lack of phosphorus often limits aquatic plant growth. When phosphorus is used up in freshwater, aquatic plant growth will stop no matter how much nitrogen is available. Phosphorus is the nutrient that limits plant growth in aquatic ecosystems. Phosphorus is found in fertilizers, manure, detergents, and sewage.
Runoff From Agricultural Land is a Source of Phosphorus to Water Runoff carries phosphorus from the land to streams and lakes. The phosphorus is either attached to eroded soil particles or dissolved in the runoff. In Alberta, most of the phosphorus in runoff is in the dissolved form. Dissolved phosphorus is the form of phosphorus that is more readily available for algae while particulate phosphorus can be a long-term supply to aquatic systems. Phosphorus in runoff can pollute surface waters and cause excessive algal and plant growth. When algal blooms exhaust the supply of phosphorus, they die and start to decompose. During decomposition, dissolved oxygen is removed from the water by microorganisms that break down the organic material. Algal blooms and excessive weed growth can have negative effects on aquatic ecosystems as well as harm human and livestock health. Blue-green algae contain toxins that can affect the liver and nervous system. Livestock and wildlife have died from consuming water containing toxins from blue-green algae. Algae blooms can plug water pumps and impair water delivery as well as produce algal scums that smell and look bad. .
(E) Iron total Iron is a white metallic element, and is the fourth most abundant element in the earth’scrust. Pure iron metal is very reactive and corrodes rapidly when exposed to air. When iron is underground, the oxygen levels are typically low so the iron in ground water is dissolved and invisible. However, when water reaches the surface and contacts air, the iron undergoes a chemical reaction that converts it to solid red rust particles. For this reason, iron is very uncommon in surface water but quite common in ground water. Corrosion of metal pipes is also sometimes a source of iron in drinking water. Iron is one of the most troublesome elements in water supplies. Making up at least 5 percent of the earth’s crust, iron is one of the earth’s most plentiful resources. Rainwater as it infiltrates the soil and underlying geologic formations dissolves iron, causing it to seep into aquifers that serve as sources of groundwater for wells. Although present in drinking water, iron is seldom found at concentrations greater than 10 milligrams per liter (mg/l) or 10 parts per million. However, as little as 0.3 mg/l can cause water to turn a reddish brown color. Iron is mainly present in water in two forms: either the soluble ferrous iron or the insoluble ferric iron. Water containing ferrous iron is clear and colorless because the iron is completely dissolved. When exposed to air in the pressure tank or atmosphere, the water turns cloudy and a reddish brown substance begins to form. This sediment is the oxidized or ferric form of iron that will not dissolve in water. (F) Chromium hexavalent Hexavalent chromium refers to chemical compounds that contain the element chromium in the +6 oxidation state. Virtually all chromium ore is processed via conversion to sodium dichromate. Seawater chromium content varies strongly, and is usually between 0.2 and 0.6 ppb.Rivers contain approximately 1 ppb of chromium, although strongly increased concentrations are possible. Phytoplankton contains approximately 4 ppm chromium, sea fish contain between 0.03 and 2 ppm, and oyster tissue contains approximately 0.7 ppm (all values dry mass). Phytoplankton has a bio concentration factor of
approximately 104 in seawater. In dissolved form chromium is present as either anionic trivalent Cr(OH)3 or as hexavalent CrO42-. The amount of dissolved Cr3+ ions is relatively low, because these form stable complexes. Oxidation ranks from Cr(II) to Cr(VI). In natural waters trivalent chromium is most abundant. Chromium does not occur freely in nature. The main chromium mineral is chromite. As was mentioned earlier, chromium compounds can be found in waters only in trace amounts. The element and its compounds can be discharged in surface water through various industries. It is applied for example for metal surface refinery and in alloys. Stainless steel consists of 12-15% chromium. Chromium metal is applied worldwide in amounts of approximately 20,000 tons per year. It may be polished and it does not oxidize when it comes in contact with air. The metal industry mainly discharged trivalent chromium. Hexavalent chromium in industrial wastewaters mainly originates from tanning and painting. Chromium compounds are applied as pigments, and 90% of the leather is tanned by means of chromium compounds. Wastewater usually contains about 5 ppm of chromium.
APPARATUS AND MATERIAL
Spectrophotometer Round sample cell DPD Total Chlorine Powder Pillow SulfaVer 4 Reagent Powder Pillow
DPD Free Chlorine Powder Pillow PhosVer 3 phosphate Powder Pillow FerroVer Iron Reagent Powder Pillow ChromaVer 3 Reagent Powder Pillow
METHODOLOGY (A) Chlorine, total 1. The Hach program was touched and the program was selected, 80 Chlor. F&T. Start button was touched. 2. A round sample cell was filled with 10 mL of sample.
3. The contents of one DPD Total Chlorine Powder Pillow was added to the sample cell. The sample cell was swirl for 20 seconds to mix. 4. The timer icon was touched. A three minute reaction period will begin. Step 5 and 6 was perform during this time period. 5. Another round sample cell was filled with 10-mL of sample. The sample cell was wiped and was placed it into the cell holder. 6. Zero button was touched . 7. Wait for three minutes after the timer beep, and the prepared sample was prepared and was placed it into the cell holder. 8. Read button was touch. (B) Sulfate 1. Hach program was touched. Program 680 Sulfate was selected and touch start button. 2. A clean sample cell with 10 mL of sample was filled. 3. The contents of one Sulfa Ver 4 Reagent Powder Pillow was added to the sample cell and was swirl to mix. 4. The timer icon was touched. OK button was touched. During five minute 5. 6. 7. 8.
reaction period begin, do not disturb the cell during this time. A second sample cell with 10 mL of sample was filled. When the timer beeps, the blank was palced into the cell holder. Zero button was touched. Within five minutes after the timer beeps, the prepared sample was
prepared into the cell holder. The Read button was touched. 9. The sample cells with soap and a brush was cleaned. (C) Cholorine, Free 1. The Hach programs was touched. 80 Chlor. F&T. The button start 2. 3. 4. 5. 6.
touch. A round sample cell was filled with 10 mL of sample. The blank was wiped and was placed into the cell holder. Zero button was touch. A second round round cell was filled with 10 mL of sample. The contents of one DPD free Chlorine Powder Pillow to the sample cell. The sample cell was swirl for 20 seconds to mix. Step 7 was repeate
immediately. 7. Within one minute of adding the reagent, the prepared sample was placed into the cell holder. 8. The Read button was touch.
(D) Phoshorus 1. The Hach program was touched. The 490 P React. PV program was selected. Start button was touched. 2. A sample cell with 10-mL of sample was filled. 3. The contents of one PhosVer 3 phosphate Powder Pillow was added to the cell. Immediately cap and invert to mix. 4. The timer icon was touched. The OK button was touched. A two minute reaction period will begin. If the sample was digested using the Acid Persulfate digestion, a ten minute reaction period is required. 5. Another sample cell was filled with 10 mL of sample. 6. When the timer beeps, the blank was wiped and was placed it into the cell holder. 7. Zero buttons was touched. 8. The prepared sample was wiped and was placed it into the cell holder.
(E) Iron, total 1. Hach programs was touched. The program was selected, 265 Iron, FerroVer and the start button was touched. 2. A clean, round sample cell was filled with 10 mL of sample. 3. The contents of one FerroVer Iron Reagent Powder Pillow was added to the sample cell and it is swirl to mix. 4. The timer icon was touched. Touch OK. A three minute reaction period will 5. 6. 7. 8.
begin. Another sample cell was filled with 10 mL of sample. When the timer beeps, the blank was placed into the cell holder. The zero buttons was touched. The prepared sample was placed into the cell holder. Touch Read.
(F) Chromium, hexavalent 1. The Hach Program was touched. The program was selected, 90 Chromium, Hex. The buttons Start was touched. 2. A round sample cell was filled with 10 mL of sample. 3. The contents of one ChromaVer 3 Reagent Powder Pillow was added to the sample sell. Cap and invert gently to mix. A purple color will form if hexavalent chromium was present.
4. The timer icon was touched and OK buttons was touched and a five 5. 6. 7. 8.
minute reaction period will begin. Another round sample cell was filled with 10 mL of sample. When the timer beeps, the blank was placed into the cell holder. The zero buttons was touched. The prepared sample was placed into the cell holder and the Read buttons was touched.
Specthrophotometer, HACH DR/2400
The bottle of the sample react with reagent
RESULT Heavy metal Chlorine total Sulfate Chlorine free Phosphorus Iron total Chromium hexavalent
Observation colour Light pink Cloudy Light pink Light blue Pale orange Colourless
Reading 0.08 mg/L Cl2 5 mg/L SO420.02 mg/L Cl2 0.15 mg/L PO430.23 mg/L Fe 0.01 Cr6+
DISCUSSION From this experiment, the water sample from Section 7 was taken and the testing of heavy metal of the water sample is done. The heavy metal that needs to determined is chlorine total, sulfate, chlorine free, phosphorus, iron total and chromium hevalent, so that the water sample can be analysed whether it is safe to aquatic life. From this experiment, the quantity of heavy metal such as chlorine total, sulfate, chlorine free, phosphorus, iron total and chromium hexavalent can be determined by using the Hach Program. From the results, the observation colour of the chlorine total present in water will change the colour to the light pink. From the theory, when there is chlorine in water sample, the colour of the water sample will be change to pink colour. The observation colour of the chlorine free present in water will change the colour to the light pink. The reading was 0.02 mg/L Cl 2 which is according to the theory, if there is chlorine, the water sample will change the colour to pink. Chlorine is usually use for chlorination process to clean the water, but in higher level concentration of chlorine, it will caused carcinogenic and skin irritation. The observation colour of the sulfate total present in water will change the colour to the cloudy and the reading was 5 mg/L SO42-. This value is not too danger to the aquatic life and the activity of the aquatic life still can be growth. Form the theory, if there is sulfatein water sample, it will change the colour to the white turbidity. So from this water sample, sulfate is still present but in the small quantity. The sources of sulfate are usually from the soil, oxidation ores, and one of the major component of rain. Sulfate may have a laxative effect that can lead to dehydration and is of special concern for infants. With time, people and young livestock will become acclimated to the sulfate and the symptoms disappear. Sulfur-oxidizing bacteria pose no known human health risk. The maximum contaminate level is 250 mg/L. It can be seen that the phosphorus change to the light blue colour and the reading was 0.15 mg/L PO43- and same with theory which is if there is a chlorine, the colour of water sample will change to blue colour while the iron total change to the pale orange colour which is same with the theory and the reading was 0.23 mg/L Fe which is the reading of iron total is too high and can harmful the aquatic life since the 0.3 mg/L in normal seawater will change the reddish brown colour. The source of
phosphorus is usually from the fertilizer, detergent and sewage. Rainfall can cause varying amounts of phosphates to wash from farm soils into nearby waterways. Phosphate will stimulate the growth of plankton and aquatic plants which provide food for fish. This may cause an increase in the fish population and improve the overall water quality and the excessive of phosphorus will be encourage the growth of the aquatic plant, so when the growth of the aquatic plant is increased, the oxygen taken for respiration will be increased and it will affect the fish as the oxygen in water for them will be decreased. So, the aquatic life will be easily died. From the observation colour of chromium hexavalent it will change to colourless, so it means that the water sample is not have the chromium since the reading was 0.01 Cr6+ and the reading is still small which is in the normal seawater, the reading is usally 0.2-0.6 ppm. So, this water sample is safe for use for aquatic life. The major sources of chromium in water are usually from air conditioning coolants, engine part and brake emissions. It is very toxic to flora and fauna and to mutagenic for human. It can caused allergic and asthmatic reactions and is 1000 times as toxic as trivalent chromium. The health effect of human will caused diarrhoea, stomach and intestinal bleedings, cramps, and liver and kidney damage. The higher the reading of the heavy metal in water, the higher dangerous exposure of aquatic life and can affect the human life when the water is process as a drinking water for daily life. The presence of heavy metal in water can be harmful to the aquatic life, human life and can give the effects of the environment.
CONCLUSION It can be concluded that the heavy metal that traced from this experiment are chlorine total, sulfate, chlorine free, phosphorus, iron total and chromium hexavalent. From this experiment, chlorine total, chlorine free, phosphorus and iron total present in water sample, since sulfate and chromium have a small quantity in water sample when the tested was done for them. So, the water is still safe for aquatic life and for drinking, but the water need to be treat first before can be used for drinking since nowadays there are several treatment of water such as ion exchange, reverse osmosis, chemical oxidation and electrochemical applications treatment depend on the what of heavy metal that present in water with the suitable of treatment that can be used.
RECOMMENDATION Several recommendations can be done for the next experiment so that the experiment can running smoothly without any problem and can get the accurate value of the result. For the first recommendation for this is it can be recommended that the sources of another water sample can be taken too so that the comparison between two sources of water can be done to analysed which water have the highest of heavy metal since the water sample that taken from this experiment is from the lake at Section 7. Other than that, the bottle of the sample with the reagent need to be inverted gently for several times to make sure that the mixture is mix properly so that the value of the result of metal present that in water sample can be determined. Next, the student should wipe the sample bottle first before it put in cell holder with tissue to prevent the finger print or wetting water that can be result of heavy metal and affect the overall reading value of heavy metal.
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Malaysia interim national water quality standard (INWQS)