Niosh SHO Exam Notes - Module 3 Question and Answer.pdf

Module 3:

Remark

M3-C1

Overview of Occupational Health

M3-C2

Occupational Health Standard

M3-C3

Introduction and Fundamentals of Toxicology 1.

a) List out the factors that influence the toxicity/damaging effect of substances on the body. 1.) Method of exposure to chemical determined the rate of absorption and its target organ. 2.) Type of chemical entering the body determine the different toxic effects. 3.) Chemical and physical characteristics of the material determine its absorption rate. This include the molecule size, volatility, solubility etc. 4.) Intensity of exposure. This includes the dosage, frequency and duration of exposure. A higher does most likely have a more hazardous effect than a lower dose. 5.) Interaction of various materials. Simultaneous exposure to various chemicals may increase or decrease its toxicity effect. 6.) Age. Elderly person has a different physiology and metabolic rate than younger individuals. 7.) Gender. 8.) Genetics, immunity, hormones and diet

b) Describe the mode of entry of substance into the body 1.) Inhalation: Most common route of entry (gases, vapors, dusts or mists) 2.) Skin absorption: Common for fat soluble chemicals (liquid or droplet), Some substances are absorbed through the skin and enter the bloodstream. Broken, cut or cracked skin will allow substances to enter the body more easily. 3.) Ingestion: Less common (personal hygiene, work practices). Chemicals that get in or on food, cigarettes, utensils or hands can be swallowed 4.) Injection: Happened when injection needles are used, may occur through mechanical injury from "sharps".

2.

Describe the main processes upon chemical entered the human body. Refer to textbook module 3 page 55 Chemicals goes through 4 main processes upon entering to disposal from the human body: - Absorption: Process where toxic chemical entering the body. Most common route of entry is through 1) Inhalation: gasses enter through inhalation and are absorbed into the lungs 2) Skin absorption: absorbed if the skin is damaged or torn. - Distribution: Process where the chemical and its metabolites are distributed into the body. - Metabolism: Process in which the absorbed chemical takes another form 1) Bio activation: Non-toxic materials changed to toxic 2) Detoxification: Toxic materials changed to non-toxic - Excretion: Process of disposing the absorbed material and its metabolite from the body.

3.

2 main factors to determine the chemical toxicity 1.) Method of exposure to chemical determined the rate of absorption and its target organ. 2.) Type of chemical entering the body determine the different toxic effects. 3.) Chemical and physical characteristics of the material determine its absorption rate. This include the molecule size, volatility, solubility etc. 4.) Intensity of exposure. This includes the dosage, frequency and duration of exposure. A higher does most likely have a more hazardous effect than a lower dose. 5.) Interaction of various materials. Simultaneous exposure to various chemicals may increase or decrease its toxicity effect. 6.) Age. Elderly person has a different physiology and metabolic rate than younger individuals. 7.) Gender. 8.) Genetics, immunity, hormones and diet

4.

Characteristics of chronic exposure (relative to acute) 1.)

Acute exposure: usually occurs for a short duration (second/minutes), usually in high doses. Eg, spillage or chemical release. The effect (急性暴露)

2.)

Chronic exposure: is long term exposure is small doses. It happens daily, weekly and at times, throughout whole duration of working (慢性暴露)

5.

is known as acute effect

in a certain factory. The effect is known as chronic effect. Eg. Exposure to asbestos or tobacco smoke.

True statement about PEL (boundary between safe & unsafe dose) Permissible exposure limit means: - A ceiling limit - Maximum exposure limit - An eight-hour time-weighted average airborne concentration (TWA), TWA levels are usually lower than ceiling values. Most toxic materials have a certain level which if exposed does not cause any harmful effects. This does is known as threshold dose, also known as No Observable Adverse Effect Level (NOAEL). NOAEL is the basis for the determination of the Permissible exposure limit.

M3-C4

Overview and Basic Principles of Industrial Hygiene 1.

Name 6 (six) common analytical methods in occupational hygiene laboratory analysis.

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1.) Atomic Absorption Spectrophotometry (AAS)

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2.) Electron Microscopy (Transmission and scanning microscopes)

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3.) Gas Chromatography (GC)

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4.) High-Pressure Liquid Chromatography (HPLC)

Refer

5.) Inductively Coupled Argon Plasma Spectrophotometry (ICAP)

textbook

6.) Ion Chromatography (IC)

module 3

7.) Optical Microscopy (Phase-contrast and polarized-light microscopes)

page116

8.) Ultraviolet/Visible Spectrophotometry 9.) X-ray Diffraction 10.) Gravimetric

M3-C5

Chemical Hazard Management 1.

Discuss the safe procedures of chemicals that should be carried out during receiving, handling, storing and disposal. 1.)

Receiving of chemicals at workplace

1.) Item verification： Ensure order is the same as what is received and done by at least 2 trained and experienced staff 2.) check labels on packaging or containers： All labels must have the following information , i.e chemical name, hazard signs and symbols, risk phrases and safety warnings, supplier information 3.) Check the availability of hazard information：Ensure the supplier provides CSDS. 4.) Check the integrity of packaging and container： Check for leakage, change of shape, rust or flaws and weakness of the package or container. Soiled /rejected packages must be returned to the suppliers.

2.)

Chemical storage

1.) Chemical storage must take the following into consideration： 2.) Storage area is in isolation from processing area through either separation by fire proof guard or in a separate building 3.) Avoid storing materials that may have reactions to each other together. Segregation should be with space or physical barriers 4.) Reduce the risk of physical damage such as using proper risk management or rack organizing processes. 5.) Fire proof walls , doors or obstructions to prevent the spreading of fire/smoke 6.) Limit the quantity of materials stored to the quantity required for operation to minimize the outcome of potential accidents 7.) Store chemicals in a safe and efficient manner, with a good ventilation system, Temperature and humidity controls should also be in place

3.)

Handling

1.) The employer must train the employee to understand the risk: CSDS, label. before using chemicals and how to handle chemical spills 2.) Proper training and be informed of the potential risks and the safety measures required

3.) Use of PPE 4.) Practice safe working procedures and activities. 4.)

Disposal

1.) Label the chemical waste according to the EQA (Scheduled Wastes) Regulations 1989 2.) Temporary waste storage area to protect the chemicals from the weather and spill control 3.) Safe work procedures and use of PPE when handling waste 4.) Safe disposal according to DOE guidelines

M3-C6

Chemical Monitoring 1.

The requirements for employee exposure monitoring or personal monitoring had been incorporated in the Factories and Machinery Lead Regulations (1984), Asbestos Process Regulations (1986), Noise Exposure Regulation (1989) and Mineral Dust Regulations (1989). a.) What is meant by the term personal monitoring? Personal monitoring use to determine if there is compliance with the exposure limits of the standard and to monitor the exposure level of a worker to a specific hazard. A sampling devices/equipment is placed on the worker where the sensor of sample collector is positioned close to the route of entry of the hazard. b) Why is it particularly important in the occupational environment? 1) To monitor the level of contaminants (living or non-living) in the work environment 2) To prevent occupational disease by identifying the potential for excessive inhalation and absorption of toxic chemicals before any significant adverse health effects occur; 3) To assess the risk to employees’ health; and evaluate the effectiveness of workplace controls, such as personal protective equipment and engineering control methods. c) Outline the various steps involved in a personal monitoring program for exposure to hazardous substance such as lead. 1. Determine who exposure to the hazardous substances above the action level. 2. Take representative samples of exposed employees who is exposed to the greatest airborne concentration level in the workplace. This is the basis for initial determination 3. If the initial determination shows employees exposure to the hazardous substances is above the action level, employer shall conduct employee exposure monitoring.

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4. If the initial determination show no employee is exposed to the concentration above action level, tehe employer make a written record of such determination. 5. If the employee exposure at or above the action level but below PEL, monitoring is repeated at least every 6 months until at least 2 consecutive measurements taken at least 7 days apart, are below the action level at which time the employer may discontinue monitoring for the employee 6. If the employee exposure is above the PEL, monitoring is repeated at quarterly until at least 2 consecutive measurements taken at least 7 days apart, are below PEL but at or above the action level at which time the employer may repeat

monitoring for the

employee at frequency specified in 5. d) Briefly explain the purpose of personal sampling, area sampling, grab sampling and integrated sampling Personal sampling –To monitor the exposure level of a worker to a specific hazard, . A sampling devices/equipment is placed on the worker where the sensor of sample collector is positioned close to the route of entry of the hazard. Area sampling – Area sampling is to monitor the level of contaminants in an area/workplace and also monitoring the integrity and results of the hazard monitoring system. Monitoring equipment is placed in specific locations in the workplace, whether near or a distance away from the source of hazard. Grab sampling – Use for grab or instantaneous sampling, Its characteristics are: (i) Spontaneous level of pollution/hazard reading ; (ii) shows the condition of the work environment at a specific time as measurements and sampling is only valid for the short span of time Integrated sampling – use for sampling airborne contaminants in the work environment. Its characteristics are (i) sample is collected and analyzed later (ii) provides higher accuracy readings on the employees exposure to airborne contaminants as time frame for sampling usually covers a longer working shift. e) Method of sampling to workers (Area? Person?) Area sampling f) Air sampling to separate and collect contaminant M3-C7

Chemical Health Risk Assessment

M3-C8

Chemical Safety Data Sheet 1.

What are the information contained in MSDS? 1. Chemical product identity and supplier details 2. Composition of chemicals for identification of hazardous properties 3. Identification of hazard 4. First aid measures 5. Fire control measures 6. Measures to handle accidental exposure 7. Handling and storage 8. Exposure control and personal protection 9. Physical and chemical characteristics 10. Stability and reactivity 11. Toxicological information 12. Ecological information 13. Disposal information 14. Transportation information 15. Date of CSDS preparation

2.

a)

CSDS – why important CSDS contain information related to hazardous chemicals or preparations which are important in the safe use and handling of chemicals at the workplace., it enable users of hazardous chemicals to:

b)



Understand the safety recommendations and their rationales



Be aware of the consequences of failure to comply to the recommendations



Identify the symptoms of over exposure to hazardous chemicals



Provide input towards the development of strategies and recommendations for safety in the use of hazardous chemicals

CPL 1997 regulation – state 4 important information from CSDS and each give 2 examples (i)

Chemical product and company identification - Product information (product name, trade name, chemical name), identification ( manufacturer name and address)

company

(ii) Physical and chemical properties – appearance, odor (iii) First aid measures – skin contact, eye contact, ingestion (iv) Handling and storage – handling, storage (v) Firefighting measures – extinguishing media, firefighting instruction, special hazards c)

When CSDS to be reviewed (2 situations) when new information on a specific hazardous chemical becomes available

M3-C9

Classification, Packaging and Labelling 1.

List the four classification of hazardous chemicals based on their physico-chemical properties and five classification based on their health effects. 1.) Based on the Physicochemical properties: Comparing test data on Physicochemical characteristics vs Physicochemical Criteria in CPL Schedule 1, Part A: I.

Explosive: may explode under the effect of flame/sensitive to shocks/friction

II.

Oxidising: highly exothermic reaction with other chemicals, particularly flammable chemicals.

III.

Extremely Flammable: Flash point