nebosh igc2 part 4

8/11/2019 Nebosh IGC2 Part 4

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CHSS Ltd 2006 Page 1 of 54wpc/SJ/ae/IGC2 Element 4 Chemical and biological health hazards and controls Sales Ref: sc/639/v3

Element 4

Chemical andBiological Hazards andControl


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Contents

Page No

Introduction 5The Human Body 6

Physiology and Anatomy 6

The Respiratory System 7

The Digestive System 7

The Cardiovascular System 8

The Urinary System 8

The Skin 9

Target Organs 10

Body Defences 11

Occupational Hygiene 14

Identification of Health Hazards 14

Measurement of Health Hazards 20

Assessment of Health Hazards 26

Control of Health Hazards 28

Specific Agents 35

Chemical Agents 35

Biological Agents 38

Pollution Control The Environment 41

Global Concerns 41

Pollution 42

Managing Waste 47

References 52


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IntroductionHealthis defined by the World Health Organisation as:

a state of complete physical, mental and social well being and not merely theabsence of disease or infirmity.(WHO 1946).

Occupational health is as important as occupational safety but generally receives farless attention from managers. There is a greater incidence of ill-health caused orexacerbated by work compared to workplace injury. However, its low profile is dueto its potential long-term nature and the difficulty in linking the ill-health effect directlyto the workplace cause. Illnesses, such as asthma or back pain, may have theirorigins outside of the workplace. A review of the available statistics point to death

from occupational disease in Britain possibly being ten times higher than the deathsfrom industrial accidents (usually about 350 people a year are killed in work relatedaccidents).

In the UK it is estimated that:

750,000 people took 13 million days off work in 1989-90 because of what theyregarded as work related disease;

730,000 people in work were affected by ill-health but took no time off; and

820,000 retired and unemployed people reported that they were affected by

the longer-term consequences of work-related illness. (HMSO, 1990).

An American study has suggested that 30% of disease is occupationally related.


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The Human BodyPhysiology and Anatomy

Physiology is the study of the function of the body, whereas anatomy is the study ofthe structure of the body.

Detailed knowledge of physiology and anatomy is not required for the NEBOSHCertificate; however, a basic understanding will assist in achieving the intendedlearning outcomes, e.g. the effects of hazardous substances in the body, their routes/ modes of entry, and body defence mechanisms.

The body consists of millions of cells, which form tissues, e.g. muscular tissue andnervous tissue, and organs, e.g. the heart, brain and kidneys.

Nerve cells have long fibres, which are capable of carrying electrical impulses; somecells in the stomach wall produce hydrochloric acid to digest food and cells in theglands produce chemicals, which influence other cells, such as the thyroid gland thatproduces adrenalin.

The work of each cell is controlled. If something affects the control of a cell, it maygrow rapidly or react in an unusual way. This sort of cell behaviour occurs in cancerwhen a group of cells grow abnormally and invade adjacent tissues.

There are five main functional systems within the human body and each of thesesystems comprises one or more organs. If one organ of the body is not functioningcorrectly then others may also be affected and affect the health of the individual as awhole. The five systems are the:

1. respiratory system;

2. digestive system;

3. cardiovascular system;

4. urinary system; and

5. skin.


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The Cardiovascular System

The heart pumps blood, which consists of

plasma, red, and white blood cells, around thebody.

The plasma assist in the clotting and scarforming (fibrosis) processes.

The red blood cells contain haemoglobin, whichdelivers oxygen and removes carbon dioxidefrom the body.

The white blood cells are of several kinds and

form part of the bodys defence mechanismagainst bacteria and viruses. The yellow fluid(pus) which can form pimples or is seen arounda splinter or cut, consists of many dead cellsand is the remains of an attack by the whiteblood cells on an invading organism.

The bloodstream also transports harmfulchemical and biological agents.

The Urinary SystemThe urinary system extracts waste products from the blood stream. The principalorgans of this system are the liver, the kidneys and the bladder. Of these the liverand the kidneys are the most important.

The Liver

The main function of the liver is to neutralise toxic substances and regulate bodytemperature. The liver will try to convert these substances into a less harmfulsubstance, this process can result in damage to the liver, but it has a great deal of

spare capacity.

Sometimes the liver alters a substance to something that will affect another organ,e.g. beta-naphthylamine (a toxic substance in rubber fumes) is converted by the liverinto a substance that can cause cancer of the bladder. The liver also maintains theblood in a clean and efficient state.

Figure 3: Blood Cells


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The Kidneys

The main function of the kidneys is to regulate the

quantity of water in the body.

They also maintain a constant balancing of thevarious salts and electrolytes essential for the healthof the body and filter out those that are either harmfulor non-essential.

Unwanted water and dissolved substances arepassed to the bladder and then leave the body.

The Skin

The skin is the largest organ of the body and itsfunction is to provide a barrier to protect the bodyagainst the environment and to exert a degreeof body temperature control.

There are two main layers of the skin, thedermis,and the epidermis.

The epidermiscontains no blood vessels or

nerve endings and its outer surface isessentially dead cells, which are constantlybeing rubbed off and replaced.

The epidermis plays an important role inprotecting the organs of the body including thedermis. The epidermis allows liquids (sweat) topass outwards through sweat glands in order tocool the body. The inner layers of theepidermis also generate melanin, a pigment that is darkened by sunlight, providingsome protection from ultra violet light.

The dermiscontains blood vessels, lymph vessels, sensory nerve endings, sweatglands and ducts, hair roots and follicles and sebaceous glands, which secrete anoily substance, called sebum. Sebum helps in maintaining hair condition but alsowaterproofs the skin and prevents it from cracking. Sebum also acts as abactericidal and fungicidal agent.

Figure 4:The Urinary Tract

Figure 5: The Skin


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Target Organs

A target organ is part of the body, e.g. lungs, brain, kidneys, liver, skin, which

sustains an adverse effect when it is exposed to, or is contaminated by, a particularharmful agent. Harmful agents include:

chemical agents, e.g. dusts, fumes, gases, mists, vapours and liquids; and

biological agents, e.g. fungi, bacteria and viruses.

Harmful agents can cause bothlocaland systemiceffects.

Local effects occur when the site of the damage is at the point of contact with thesubstance, e.g. a corrosive burn on the skin.

Systemiceffects occur when the site of damage is at a point other than the point ofcontact, such as a target organ, e.g. the effect of inhaled lead fumes on the brain.

Figure 6: Main Body Organs and Examples of Hazardous Agents, Which Havean Effect on Them

Eyes- Ammonia

LiverSolvents

Brain Lead

Nasal PassagesOrganic solvents

Lungs Asbestos,chlorine, carbon dioxide,ammonia, isocyanates,silica, organic solvents,legionella

Kidneys Leptospira

BloodCarbonmonoxide

Skin Detergents,isocyanates, mineraloils, acids, alkalisand organic solvents

Nerves Organicsolvents, lead


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Ingestion Defences

If any ingested substance is to harm the body it has to survive the acids in the

stomach and the various enzymes and bacteria within the digestive tract, whichattack and try to break down such substances. Some harmful substances or micro-organisms will cause an immediate reaction in the body causing the defencemechanisms of vomiting and diarrhoea.

Skin Defences

The skin provides an excellent defence against most substances. The epidermisprovides a protective outer layer while the dermis contains a number of defencemechanisms:

Sebum The sebum secreted by the sebaceous glands of the dermis willprovide protection against water and against weak acids andalkalis. Sebum also prevents the skin drying out when subject toheat and friction. This protection can be broken down by highconcentrations of corrosive substances, excessive abrasiveaction, burns or de-fatting. It can also be removed by the use ofsolvents, unintentionally or deliberately.

Sensory nerves The sensory nerve cells are also an important defencemechanism, alerting the brain to temperature changes andprompting involuntary defence action by the muscles (shivering).

Melanin Protection against ultra violet light is provided by the melaninpigment cells, which tan on exposure to sunlight.

Blisters, rashesand inflammation

Blisters, rashes and inflammation are all examples of the bodydefence system reaction to damage or attack and result fromincreased flow of blood, antibodies and white blood cells to theaffected area.

Table 1: Skin Defences

The most common disease of the skin due to workplace activities is dermatitis.

Dermatitis

Most occupational dermatitis isnon-infective and starts with a mildirritation and develops intoblisters, which may weep,inflammation, dryness andcracking of the skin, oftenappearing as arash. There aretwo types irritant and sensitive.

Figure 8: Example of Dermatitis Symptoms


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Irritant orcontact dermatitiscan affect any person and is a result of prolongedexposure to a substance. Factors that affect onset of the condition are theconcentration and duration of exposure.

Cement, mineral oils and de-fatting agents such as detergents and solvents, e.g.weak acids or alkalis and petrol, can cause it.

The degree of effect depends upon skin dryness, sweating, pigmentation, integrity ofthe epidermis, presence of hair, presence of dirt, pre-existing disease, temperature,humidity and friction.

Once contact from the agent is removed, full recovery will occur.

Allergic orsensitive dermatitiscauses similar symptoms and results from thesensitisation of a person to a substance - sometimes because of a single exposure

but more commonly following repeated exposure.

It can be caused by isocyanates and latex. This results in an allergic reaction onsubsequent exposure.

Allergic dermatitis will occur after exposure to very small quantities of a substance(even below the occupational exposure limits) once a person becomes sensitised toit.

Other Defences

The body has a range of other defences against harm, such as:

tears and blinking of the eye to protect against foreign bodies;

pain, e.g. manual operations involving repetitive movements, etc. will result inpain. Continuing the operations in spite of the pain can lead to permanentdamage; and

hormones, e.g. adrenalin released when the body is stressed.


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Occupational HygieneOccupational hygiene has been defined as the science of the protection andpreservation of the health of people while they are at work. Therefore it is concernedwith health hazards and involves the following four processes:

1. identificationof health hazards;

2. measurementof health hazards;

3. assessmentof health hazards; and

4. controlof health hazards.

1. Identification of Health Hazards

Forms of Chemical Agent

Chemical agents may be solid, liquid, and gas. A substance can be any one of theseforms depending on the pressure and temperature, e.g. at normal ambient pressureand temperature, water is a liquid, but when frozen is solid ice, and when heatedabove its boiling point becomes a gas, i.e. steam.

Dust

Dust is a cloud of solid particles ranging up to 150 micron in diameter. Anything over75 micron is classed as grit and is unlikely to remain airborne. A micron is onethousandth of a millimetre and is abbreviated to m. A human hair is about 50micron in diameter. Dusts are produced mechanically by grinding or similar actions,e.g. silica, flour, wood dust or general dust.

Dust is divided into two categories, depending on size:

Total inhalable dustis the total dust that will enter the nose and mouth and

lungs during breathing.

Respirable dustis dust of such a size that it is able to enter the lower levelsof the lung during normal breathing (approx. 0.5 to 7.0 micron). Respirabledust is often in the form of long particles with sharp edges which causescarring of the lung lining (fibrosis). This limits the capacity of the lungs and,therefore, the amount of air in the lungs.

Fume

Fume is made up of small metallic particles of a size from 0.001 to 1 micronproduced by, for example, combustion during the welding process.


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which will then be swallowed;

absorption:occurs through the skin and across membranes, e.g. ammonia

into the eye. Many solvents will penetrate unbroken skin and can enter theblood stream. Other substances can enter via cuts or abrasions;

direct entry:occurs through open wounds on the skin, such as dermatitis,tetanus infection and leptospirosis (Weils disease) from female rat urine; and

injection(skin puncture):caused by contact with liquids or gases underpressure or accidental puncture of the skin with contaminated sharp objects,e.g. HIV.

The effects on health on hazardous substances may be either acute or chronic.

Acuteeffects are adverse health effects resulting from a single or short-termexposure, producing an immediate or rapid effect, which is usually reversible, e.g.the intoxication effects of alcohol, an acid burn.

Chronic effects are adverse health effects resulting from prolonged or repeatedexposure with a gradualor latent, often irreversible,effect that may beunrecognisedfor a number of years, e.g. liver disease from long-term alcoholexposure, systemic effects of lead.

Classification of Hazardous Substances

Irritant : (Xi)non-corrosive substances, which, throughimmediate, prolonged or repeated contact with the skin ormucous membrane, may cause inflammation, e.g. petrol,detergent, nuisance dusts.

Corrosive: (C)substances, which, on contact with living tissue,may destroy it by burning, e.g. hydrochloric acid or strongalkalis such as ammonia.

Harmful: (Xn) substances, which, if swallowed, inhaled orpenetrate the skin, may cause damage to health.

Category 3 carcinogens, mutagens and teratogens.

Very Toxic: (T+) poisonous substances, which, in very lowquantities, may cause death, acute or chronic damage tohealth.

Toxic: (T) apoisonous substance, which, in low quantities,

may cause death, acute or chronic damage to health.


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Carcinogenic: (Carc Categories 1 and 2) substances, whichcause disorders to cell growth that may lead to cancer orincrease its incidence.

Mutagenic: (Muta Categories 1 and 2) substances, whichinduce heritable genetic defects or increase their incidence.

Toxic for reproduction (Teratogenic): (Repr Categories 1and 2) substances, which produce or increase the incidence ofnon-heritable effects in progeny and / or impairment in

reproductive functions or capacity.

Sources of Information

The principal sources of information are:

manufacturers safety data sheets, which should be provided by the supplierof the hazardous product. It is important to note that the data sheets bythemselves do not constitute a risk assessment because they do not

consider howthe substance is to be used. The 16 pieces of informationrequired on a data sheet are:

1. identification of the substance orpreparation and the company;

2. composition of the ingredients;3. hazard identification;4. first-aid measures;5. fire-fighting measures;6. accidental release measures;7. handling and storage;8. exposure controls / personal

protection;

9. physical and chemicalproperties;

10. stability and reactivity;11. toxicological information;12. ecological information;13. disposal considerations;14. transport information;15. regulatory information;

and

16. other information.

product labels, which should include thechemical name of the product, apictogram showing the classificationsymbol and an indication of the risk andsafety phases (see Table 2);

Governmental or State organisations and /or Enforcement Agency publications, e.g.The UK HSE guidance note EH 43

Carbon monoxide - Health hazards andprecautionary methods;


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ILO Codes of Practice, e.g. Safety in the Use of Chemicals at Work;

trade association publications;

worker unions and insurance companies; and

professional occupational health technical journals.

Risk Phrases Safety Phrases

These are standard phrases givingsimple information about the hazards ofa chemical in normal use.

These are standard phrases givingsimple advice on safety precautions,which may be appropriate when usingthe chemical.

R22 Harmful if swallowed. S1 Keep locked up.

R45 May cause cancer. S24 Avoid contact with the skin.

R46 May cause heritable geneticdamage.

S30 Never add water to the product.

R49 May cause cancer by inhalation. S51 Use only in well ventilated areas.

Table 2: Example Risk and Safety Phrases

Occupational Exposure Limits

An occupational exposure limit is an airborne concentration measurement of asubstance that is hazardous to health, measured over a reference time period, whichshould not be exceeded.

Different countries have adopted various frameworks for setting upper permissibleconcentrations for airborne substances within the workplace. The first standard list ofexposure limits were put together in the former Soviet Union in the 1930s. In theUSA, the ACGIH (American Conference of Governmental and Industrial Hygienists)was formed in 1941 and formed a Threshold Limit Values Committee. A range oflimits was set, known as hygiene limits, and has been used as the basis fordetermining limits elsewhere.

Not all substances are assigned an occupational exposure limit and differences inassignation and limits occur, from country to country, as there is no internationalagreement on limits, although harmonisation of standards, Indicative OccupationalExposure Limit Values (ILV), was recently agreed in Europe. Limits are publishedas, e.g.:

Threshold Limit Values (TLV) in the USA;

Indicative Limit Values (ILV) in Europe; and


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Workplace Exposure Limits (WEL) in the UK.

Hazardous substances assigned an occupational exposure limit typically fall into two

groups:

high risk substances: substances which are carcinogenic, e.g. having a riskphase R45, R46 or R49, or could cause occupational asthma or similarsevere health effects. The level of exposure to these substances should bereduced as far as is reasonably practicable; and

all other hazardous substances:which have been assigned anoccupational exposure limit. Exposure to these substances by inhalationshould be controlled adequately to ensure that the limit is not exceeded.

Most occupational exposure limits:

are subject to a long-term exposure limit (LTEL) and a short-term exposurelimit (STEL), which cover exposure over 8 hours and 15 minutes respectively.The LTEL may be exceeded proportionately if exposure is less than 8 hoursand provided that the STEL is never exceeded; and

are measured:

- in milligrams per cubic metre of air (mg/m3), (airborne particles, dust,fume, etc.);

- in parts per million of air (ppm), (airborne vapours and gases); and- in fibres per millilitre of air (fibres/ml), (airborne fibres, e.g. man made

mineral fibres).

The long-term exposure limit (LTEL) is intended to protect against chronic effects, toreduce the accumulation of harmful substances in the body that would enhance adisease risk on continuing contact.

A short-term exposure limit (STEL) is intended to prevent against acute effects suchas:

excessive irritation;

irreversible tissue damage; and

narcosis to the extent that it could impair the worker such that they have anincreased accident-proneness.

Many substances have both long-term and short-term limits, which reflect thedifferent hazardous effects that the material has on the body.


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Substance Formula CASNumber

LTEL (8-HourTWA Reference

Period)

STEL (15-MinuteReference Period)

ppm mg/m3 ppm mg/m3

Acetone CH3COCH3 67-64-1 500 1210 1500 3620

Table 3: Example of a UK WEL (HSE, 2005)

Each substance has a unique number known as a Chemical Abstract Service orCAS number, which can be referenced for measurement and risk assessment.

Limitations

Although occupational exposure limits are a useful guide, there are a number oflimitations, which should be borne in mind:

the actual doses received by workers may vary due to factors such as thework rate, which will cause more air to be inhaled. This is not allowed for inthe exposure limit framework;

chemicals can enter the body by routes other than inhalation, e.g. skinabsorption, the airborne concentration may not be fully indicative of the dosereceived;

toxicological data on which limits are based are not necessarily infallible;

errors in estimating exposures may be significant; and

many substances do not have a limit set, which leaves organisations, whichmay have little technical expertise, with the difficult task of setting an in-house limit.

2. Measurement of Health Hazards

Survey Techniques for Health Risks

The measurement of hazardous substance concentrations in the atmosphere will berequired when there are likely to be serious risks to health in the event of a failure ordeterioration of control measures. Therefore, measurement would be necessary ifthere were uncertainty that workplace exposure limits had not been exceeded or thatparticular control measures were not working properly. Survey techniques include:

an initial appraisal, e.g. information gathering and observation;

a basic survey, e.g. qualitative or quantitative indication (short-term grabsampling); and


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a full survey, e.g. detailed quantitative long-term sampling.

Initial Appraisal

At first an initial appraisal of the hazards and risks needs to be undertaken, takinginto account all of the relevant factors such as:

substances used, including physical forms and properties;

processes involved, including points of release;

persons who could be affected;

work practices, including means by which substances could be released;

whether RPE or other forms of PPE is worn and its effectiveness orergonomic concerns; and

relevant Occupational Exposure Limits.

From this information and some qualitative observations a decision can then bemade regarding the need for measuring (monitoring).

Basic Survey

Qualitative observations may be made to give an indication of whether there aregrounds to require quantitative measurement, e.g. using smoke tubes or dustobservation lamps.

The smoke tubewill give an indication of the direction and relative speed of airmovements. It is often used to observe the effectiveness of a ventilation system.

The dust lampwill allow dusts, which are normally invisible to the naked eye, to beobserved in a manner similar to a beam of sunlight in a darkened room.

Neither device can estimate the concentration of the dust cloud but may indicate thatair monitoring is required.


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Figure 9: Use of a Dust Lamp

A quantitative indication of a gas or vapour can be achieved using a stain tubedetector(grab sampler). A sample of air is drawn over crystals in a calibrated tubevia a hand pump. The gas or vapour needs to be identified before this method isused as the specific tube for the substance should be obtained.

The presence of a hazardous substance causes the crystals to change colour. The

tube is calibrated so that the extent of the crystal colour change along the tubeindicates the concentration in parts per million (ppm) of the hazardous substance inthe air sample.

There are over 200 tubes available, e.g. oxygen, carbon monoxide, sulphur dioxide,hydrogen sulphide, acetone, etc.

Figure 10: Example of a Grab Sampler and Tubes

Lamp - either

traversed by hand toilluminate dust sourceor mounted on a stand Dust

Observer, orcamera, viewingtowards lampwhilst shieldingeyes from glare


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Figure 11: Stain Detector Tube

An extension tube is available to permit sampling in a confined space without the

tester having to enter the space.

Advantages of grab sampling Disadvantages of grab sampling

low cost;

takes little time;

immediate result;

operators need little experience;

gives indication duringemergency spillages, etc.; and

good for coarse indication ofmeasurement.

inaccurate;

results depend upon positioning ofthe tube;

only a snap shot is taken during asmall amount of time;

the pump may be inefficient orinaccurate in each sample;

chemical use only (no dusts); and

substance specific the substancesampled must be known.

1 2 3 5 1020

Glass tube Direction of flow

Fused tip Pre-layer Fused tip

Porousgranules,e.g. silica gel,chemicalreagent Scale

divisions

READ

1 2 3 5 1020

Scale


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Full Survey

Where accurate measurements are required the long-termsamplingmethod is

used.

Long-term does not necessarily refer to a long time period, it could be based on afew minutes, or several days of sampling.

Unlike grab sampling, which just measures an instantaneous concentration, long-term sampling enables a Time Weighted Average (TWA) concentration to bedetermined, which allows for comparison against an occupational exposure limit andappropriate judgements to be made whether control is achieved.

Direct reading and indirect readingare the two principal methods of long-termsampling.

Direct Reading Instruments

These are very technical instruments, e.g. portable infra-red gas analyser used totest for gases such as oxygen, carbon dioxide, carbon monoxide, hydrogen sulphide,chlorine, which are usually operated by specialists. They are very accurate andprovide a quick reading. Some of these instruments will provide a print out of thevarious levels during the sampling period as well as converting the reading to theTime Weighted Average (TWA).

Permanent direct reading static sampling equipment is used in some industries. Thisis more properly defined as Monitoring Equipment, which will normally give an alarm

if certain levels of oxygen or a toxic gas are encountered and does not provide anyfacility for a direct reading of concentration in air; these are also used for monitoringduring work rather than evaluation of levels.

There is a range of direct reading instruments available to indicate the levels offlammable gas or vapour in air, sometimes termed Explosimeters. These will eitherbe set for the specific Upper Flammable Limit or Upper Explosive Level (UFL / UEL)and Lower Flammable Level or Lower Explosive Level (LFL / LEL) of the particulargas or vapour, e.g. methane. Commonly direct reading instruments used in industryinclude three in one or four in one multi-gas instruments, which continuallymeasure oxygen level, flammable gas and one or two toxic gases such as carbonmonoxide and / or hydrogen sulphide. This type of instrumentation can be used tomonitor atmospheres for work within confined spaces.

Indirect Reading Instruments

These provide methods of sampling the atmosphere, which is then analysed in alaboratory to determine the amount of material collected. They have the advantagethat the results are accurate and give a TWA, however it takes time to obtain a result.Various forms of equipment are used depending on the material being sampled:

passive samplers. These are usually in the form of a badge or tubesamplers, onto which the contaminant diffuses. The monitoring time is noted

and the badge is then sent to an approved laboratory for analysis where acalculation is made to produce a TWA for comparison with the appropriate


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LTEL / STEL. The advantage of this method is that no pump is required andthe sampler can be left for several days or weeks if necessary; and

active samplers.A pre-set volume of sample air is continuously drawnthrough a collection medium or filter housed in a sampling head connected toa pump via tubing. The monitoring time is noted and the filter is sent to anapproved laboratory for analysis where a calculation is made to produce aTWA for comparison with the appropriate LTEL / STEL. It is more accuratethan a stain tube detector and can be used for both gases and dusts.

The sampling can be either:

personal sampling. These may be passive or active samplers:

- for passive sampling the badge or tube sampler is placed in the

workers breathing zone; and- for active sampling the sampling head is placed in the workers

breathing zone with the pump strapped to the workers waist; or

static sampling. These may be passive or active samplers. They are placedat static points, usually operator stations, and are used for environmentalsampling.

Figure 12: Passive and Active Personal Sampling

Passive Sampling Active Sampling


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3. Assessment of Health Hazards

Employers should identify, risk assess and control workers exposure to hazardoussubstances. A hazardous substance is a substance, which:

has a chemicalhealth hazard label: very toxic, toxic, harmful, corrosive orirritant;

is a carcinogen, mutagenor is toxic for reproduction;

has an assignedoccupational exposure limit;

is a biological agent;

is a dust in substantial concentration, e.g.:

- total inhalable dust 10 mg/m3;- respirable dust 4 mg/m3; and

is any other substance defined as hazardous to health, e.g. pesticides.

The employer should:

carry out suitable and sufficient risk assessment;

adequately control exposure of employees to hazardous substances;

ensure that control measures provided should be used properly;

regularly maintain control measures;

monitor employee exposures to hazardous substances where:

- failure or deterioration of the control measures could result in aserious health effect;

- measurement is necessary so as to be sure an occupational exposurelimit is not exceeded; and

- necessary as an additional check on the effectiveness of control

measures;

provide health surveillance for employees where:

- an identifiable disease or adverse health effect may be related to theexposure;

- there is a reasonable likelihood of disease or adverse health effect;- a valid detection technique exists; and- the detection technique is of low risk to the employee;

provide employees affected by the hazardous substances with sufficient

information, instruction and training.Risk Assessment


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The stages of a hazardous substance risk assessment are very similar to those of ageneral risk assessment:

1. Look for the hazards

The safety data sheet and / or hazard warning labels will indicate whether thesubstance is hazardous. Some hazardous substances may be produced bythe process itself, e.g. welding or soldering fume.

Information will be required on the:

work activity: duration and frequency;

identity of the substance;

toxicity of the substance, e.g. whether it is assigned an occupational

exposure limit; form of the substance;

concentration of the substance;

routes of entry into the body;

results of personal or static monitoring;

information about incidents / accidents / ill-health; and

results of health surveillance.

2. Decide who might be harmed and how

The operator and others who may be affected, especially vulnerable people,

e.g. pregnant and young workers, those with health problems such asasthma, etc.

3. Evaluate the health risks and decide whether existing precautions areadequate or more should be done

The likelihood and severity of the risk should be established.

The existing control measures should be identified and considered, toascertain whether they are used and adequately control exposures to thesubstance.

A judgement about the need for further control measures will need to bemade. The hierarchy of control should be considered to establish the mosteffective means of control.

4. Record the findings

The significant findings of the assessment should be recorded.

Personal monitoring and health surveillance records should be kept for 40years, whereas static monitoring records, where individuals are not named,should be kept for at least 5 years.


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Segregate the People

Barriers and ventilated control booths are often provided in molten metal processes

to protect employees from fumes and heat, etc.

Control

Control by engineering control, e.g. LEV, pumping chemicals instead of manuallypouring them; and by changing work patterns or methods, e.g. limiting the time,frequency (job rotation) and number of persons exposed.

Engineering Control

Local Exhaust Ventilation (LEV)

LEV is a mechanical system of ventilation designed to remove a specific contaminantfrom its source, e.g. welding fume. It consists of the following:

a receptor or capture hood;

ducting to remove the contaminant;

an air cleaning device, e.g. filter to remove the contaminant from the air;

a fan to ensure an adequate ventilation rate for the contaminant. This will bedependent on the size of the particles and the size of the LEV system; and

a discharge point.


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Figure 13: LEV

LEV is an effective way to control exposure from a specific source of contaminant,however, the following must be considered:

the system should be designed to remove the specific contaminate;

the initial performance of LEV should be checked against design specificationby a competent person;

the LEV should be examined / tested annually. The test results should thenbe compared with the design specification to detect deterioration inperformance. Records of examinations / testing should be kept, e.g. for 5years;

LEV may become inefficient because of:

- blocked filters;

- lack of maintenance;- positioning the hood too far away

from the contaminant;

- unauthorised alterations;- broken ducting;

- wear / corrosion of fan blades;

- incorrect setting;- increased contaminant levels;- inadequate design; and- failure of operators to use it.

there should be regular user checks to ensure performance, e.g.:

- clean ducting;- repair physical damage;

- reposition hoods to correct angles;

- check the condition and correct installation of filters;

Discharge to atmosphere

Main ductFilter

Fan

Circular saw

Hood Branchducting

Dust collectionbags


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- examine fan blades to ensure there is no build up of contaminant;- tightening and cleaning of drive belts; and- general lubrication of moving parts.

Employers should ensure employees:

make proper use of control measures provided; and

report defects in them.

Dilution or General Ventilation

General or dilution ventilation is designed to induce a flow of air through a room todilute or displace contaminants.

Its use is only appropriate when dealing with low toxicity, low density contaminants(not dusts), which are uniformly evolved in small quantities. It is suitable where it isnot practicable to extract the contaminant close to its point of origin, e.g. where thereis no specific point of contaminant release or heat source.

Figure 14: General Ventilation

Maintenance of Controls

Systems of adequate control should be in place for normal operations, emergenciesand maintenance. Engineering control measures will only remain effective if there isa programme of preventative maintenance available. Maintenance will involve thecleaning, testing and, possibly, the dismantling of equipment. It could involveentering confined spaces. It will almost certainly require hazardous substances to behandled and waste material to be safely disposed. It may also require a permit-to-work procedure to be in place since the control equipment will be inoperative duringthe maintenance operations. Records of maintenance should be kept for at least 5years.


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Change the Work Pattern or Method

Reduced time and frequency of exposure can be achieved by:

allowing employees to have several breaks during the working day;

job rotation; and

providing exclusion zones to reduce the number of persons exposed to ahazard.

The work method can be changed by:

purchasing substances in small containers rather than bulk drums to preventthe need for decanting; and

developing safe system of work and review methods of working, e.g.vacuuming dusts rather than sweeping.

Hygiene and Housekeeping

All eating, drinking or smoking should be prohibited in the area where hazardoussubstances are used. Adequate welfare arrangements, particularly washing andfirst-aid facilities should be situated near to the area where hazardous substancesare used and good hygiene practices followed. Personal hygiene is very importantfor workers exposed to hazardous substances and they should wash their hands

thoroughly before eating, drinking or smoking.

Contaminated clothing and overalls need to be removed and cleaned on a regularbasis.

Good housekeeping measures will reduce the risks from hazardous substances, e.g.by ensuring that only the minimum quantity of the substance is kept at theworkstation and that all infection, contamination and inhalation hazards are removed.

Personal Protective Equipment (PPE)

Personal protective equipment used for protection from hazardous substances

include:

respiratory protection, e.g. chlorine;

hand and skin protection, e.g.detergents and solvents;

eye protection, e.g. corrosives andammonia; and

protective clothing, e.g. chemical splashsuits to protect against acids andbiological agents.


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Discipline

If the wearing of personal protective equipment is required, then supervisors should

enforce the rule and lead by example. Ultimately disciplinary procedures should beinvoked for non-compliance.

Other Controls

Information, Instruction and Training

Employees will require sufficient information and instructions on the:

nature of the substances they work with and the risks created by exposure tothose substances;

control measures, their purpose and how to use them;

use of personal protective equipment and clothing;

results of any exposure monitoring and health surveillance (which should beanonymous); and

emergency procedures.

Emergency Controls

Emergencies can range from spillages to major fires involving serious air pollutionincidents. The following points should be considered when an emergency arisesinvolving hazardous substances:

loss of ventilation, if this poses a risk to health then the ventilation systemshould be fitted with an audible and a visible alarm;

availability of personal protective equipment;

provision of emergency showers and eye-wash facilities;

spillage and leakage, e.g. spillage booms, sawdust, and a spillage procedure;and

evacuation procedures including the alerting of neighbours.

A spillage procedure would involve:

isolation of the area;

evacuation of employees at risk; the provision of bunding to contain thespillage;

issue of appropriate PPE to those carrying out the task, e.g. filter face mask;


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contact with emergency services (in high risk situations); and

the safe disposal of the spilled substance and any absorbent material used.

Health Surveillance

Environmental monitoring measures the level of substance in the workplace beforepeople have been exposed and suffered any harm. Health surveillance detects thestart of an ill-health problem and collects data on ill-health occurrences. It gives anindication of the effectiveness of the control procedures, but this is not its primaryfunction. This might involve examinations by a doctor or trained nurse. But in somecases trained supervisors could, for example, check employees skin for dermatitis,or ask questions about breathing difficulties where work involves substances knownto cause asthma.


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Specific Agents

Chemical Agents

Ammoniais a strongly alkaline colourless gas with a pungent odour. It is a corrosivesubstance, which even in small concentrations can cause irritation to the eyes andupper respiratory tract. In large concentrations it can cause blindness and pulmonaryoedema (fluid in the lungs). Therefore, when maintaining equipment containingammonia the wearing of good eye and respiratory protective equipment is essential.

It is readily soluble in water, which can lead to severe burns if concentrated solutionsare splashed onto the skin or into eyes.

It is widely used in the printing industry and in the manufacture of fertilisers andrefrigerants. Most work on ammonia plant requires a permit-to work procedure.

Asbestosis a term used to describe a group of fibrous silicates. They are naturallyoccurring minerals, which are highly resistant totemperature, pressure and acids. Asbestos was verymuch in demand for its fire resistant properties andwas used in insulation materials, brake linings and fireproofing devices.

Fibres, such as asbestos fibres and man made mineralfibres, have difference characteristics to dust particles.The sizes that are important are the length, thediameter and the length to diameter ratio.

There are three main types of asbestos commonlycalled:

blue (crocidolite);

brown (amosite); and

white (chrysotile).

All are dangerous, but blue and brown asbestos are considered to be morehazardous than white.

Asbestos will only pose a risk to health if asbestos fibres are released into the air.They form a very fine dust that is often invisible to the naked eye.

Breathing in air containing asbestos dust can lead to chronic asbestos-relateddiseases, e.g.:

asbestosis (a chronic fibrotic lung disease);

lung cancer; and


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mesothelioma, a cancer of the lining of the lung.

The combined effect of smoking tobacco and working with asbestos increases the

risk of development of lung cancer.

Asbestos related diseases often take many years to manifest after exposure, andcurrently kill an estimated 3,000 people a year in Great Britain. Although exposure toasbestos fibres should now be strictly controlled, over the next 25 years it isestimated that 250,000 employees will die from asbestos exposure. (ProfessorJulian Peto, 1999).

Asbestos may be encountered in a building in:

pipe lagging;

wall and roof panels;

ceiling tiles;

textured coatings, e.g. fire resistant encapsulation of metal beams;

insulation materials; and

gaskets and other seals.

Carbon dioxideis a colourless and odourless gas, which is heavier than air. Lowlevels of carbon dioxide increase the rate of respiration, whereas high levels depressthe rate of respiration leading to rapid unconsciousness and possible death. It isproduced in fermentation processes such as in bakeries and breweries.

Carbon monoxideis a colourless, odourless and tasteless gas usually foundwherever incomplete combustion occurs, e.g. in domestic boilers, vehicle exhausts,furnaces and steelworks.

Inhalation of the gas results in headaches, drowsiness, flushed pink appearanceand ultimately in asphyxiation. Because carbon monoxide is more readily absorbedby the haemoglobin in the red blood cells than oxygen, forming carboxyhaemoglobin,it is termed a chemical asphyxiant. The supply of oxygen to all body organs,

including the brain is therefore impaired.

Chlorineis a greenish, toxic gas with a pungent smell, which is highly irritant to therespiratory system. It may also cause abdominal pain, nausea and vomiting. It isused as a disinfectant for drinking water and swimming pool water.

Dusts, e.g. nuisance dust can cause rhinitis, asthma, bronchitis, emphysema or,depending upon the agent a more specific condition, e.g. asbestosis (asbestos),silicosis (silica), byssinosis (cotton fibres), farmers lung (mould spores in hay).

Dusts may be measured using visual signs of dust on objects, dust lamps, directreading instruments and static or personal sampling followed by laboratory analysis.


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Control measures include:

elimination, e.g. do not carry out grinding processes on site;

substitution, e.g. of powders for pellets,

enclosure of the process,

local exhaust ventilation (LEV) to extract close to the source;

vacuuming instead of sweeping;

damping down;

limiting the time of exposure;

limiting the numbers exposed; and

PPE, e.g. filter facemask, if the dust cannot be eliminated or reduced.

Leadis a heavy, soft and easily worked metal. It is used in many industries but ismost commonly associated with plumbing and roofing work. It can enter the body byeating contaminated food but more probably by breathing lead fumes or dust. Thegreatest number of lead poisoning cases in recent years have occurred to workersinvolved in cutting up lead painted steel work with gas cutting equipment.

Acute lead poisoning can result in nausea, headaches, and effect on the nervoussystem and sometimes death in severe cases. Lead is stored in the body andaccumulates, although over a long period the body will excrete it. Prolongedexposure to lead will result in the chronic effects of loss of muscle strength, anaemia,and mental disorders. It is an inhalation and ingestion health hazard.

Organic lead (tetra-ethyl lead) is used as an anti-knock additive in petrol and isprimarily associated with psychiatric effects such as insomnia, hyper-excitability andmania.

Organic solventsdissolve other substances. They can also be used as a cleaningand degreasing agents.

Most solvents are volatile, evaporating quickly at room temperature. Because manysolvents evaporate readily their vapours can be drawn into the lungs.

The acuteeffects of solvent exposure include irritation of the eyes, skin, throat, andlungs. Certain solvents can also affect the brain. The effects of single and continuedexposures will vary with the particular solvent and its concentration, but can rangefrom headaches, nausea, and dizziness to loss of consciousness (narcosis) andeven death. These reactions can increase the risk of accidents. Recovery from sucheffects is usually fairly rapid provided that the employee is removed from exposure tothe vapour. However, deaths have resulted from exposure to high solvent levels inconfined spaces.

The chronic ill-health effects of solvents are less clear. Some medical research has


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shown the development of mental illness and brain disease after long-term exposureto solvents. Prolonged or repeated exposure to solvents such as trichloroethylene,n-hexane, methyl butyl ketone and carbon disulphide may damage peripheral nerves.Symptoms of such damage include disturbance of sensation and weakness or partialloss of limb movement. These effects are serious but rare.

Solvents also dissolve fats and greases so they can penetrate the natural barrier ofthe skin, particularly the hands, arms and face, causing dermatitis or other skindisorders. They are an inhalation, ingestion and absorption health hazard.

Isocyanatesare volatile organic compounds widely used in industry for productssuch as surface coatings; especially spray painting vehicles, production ofpolyurethane rubbers and foams, printing and lamination work and the manufactureof footwear (soles and synthetic uppers).

They are irritants and sensitisers. Inflammation of the nasal passages and throat,bronchitis leading to asthma and rhinitis, are typical reactions to many isocyanates.They are an inhalation, ingestion and absorption health hazard.

Silicais present in substantial quantities in sand, sandstone and granite and oftenforms a considerable part of clay, shale and slate. Concrete and mortar may alsocontain crystalline silica. The health hazard comes from breathing in the very finedust, which can lead to silicosis. Silicosis involves scarring (fibrosis) of the lungtissues leading to breathing difficulties. The disease may be acute arising from short-term exposures to high concentrations or more usually chronically due to exposureover a long period of time. Fibrosis of the lung tissue from chronic silicosis leads to acorresponding loss of function. Sufferers usually become housebound and often die

prematurely due to heart failure. Fibrosis of the lung tissue has also been linked tolung cancer. Work activities, exposing workers to the dust include stone masonry,sand blasting, demolition and tunnelling. It is an inhalation health hazard.

Biological Agents

Leptospirosis or Weils diseaseis caused by a bacteria found in the urine offemale rats. It is a form of jaundice attacking the kidneys and liver causing hightemperatures and headaches and may be fatal. It enters the body either throughpuncture of the skin or by ingestion. The most common source is contaminatedwater in a river, sewer or ditch and workers, such as canal or sewer workers are

most at risk. It is an ingestion and absorption health hazard.

Controls include vermin control, housekeeping and removal of waste, personalhygiene, covering damaged skin and the provision of information, training andinstruction.

Legionellais an airborne bacterium and is found in a variety of water sources, e.g.cooling towers, water distribution pipework, stagnant water, etc. It is caused byinhalation of airborne droplets of water containing the legionella bacteria, leading to aform of pneumonia (Legionnaires disease) caused by the bacteria penetrating to thealveoli in the lungs. The symptoms are similar to pneumonia, i.e. breathingdifficulties, high temperature and possible death.

Death is most likely in middle-aged smokers, although those with a suppressed


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immune system and the elderly are also vulnerable. The non-pneumonic version ofthe disease, which is less serious, is known as Pontiac Fever.

The conditions in air conditioning systems, if not properly maintained and treated,can be ideal for the bacteria to breed and then enter the atmosphere in the building.

Controls include temperature control and monitoring, maintaining a regular flow ofwater, avoiding dead-legs in pipework, biocide treatment, effective cleaning andmaintenance regimes and provision of information, training and instruction.

Hepatitisis a disease of the liver and can cause high temperatures, nausea andjaundice. It can be caused by hazardous substances (some organic solvents) or by avirus. The virus can be transmitted from infected faeces (Hepatitis A) or by infectedblood (Hepatitis B and C). Health workers, care workers, and any workers handlingbodily fluids are particularly at risk from the disease. It is an ingestion and direct

entry health hazard. The normal precautions include good personal hygieneparticularly when handling food and in the use of blood products.

Biological organisms can enter the body by inhalation, ingestion, injection and directcontact though wounds.

Key control measures include:

cleaning / disinfection;

water treatment, e.g. chlorination to prevent legionella in water systems;

vermin control, e.g. to prevent leptospirosis from rats;

containment of the biological agent, e.g. microbiological safety cabinets;

avoidance of sharp implements, e.g. glass containers that could break,scalpels;

proper disposal of contaminated waste;

immunisation, e.g. against hepatitis;

personal hygiene; and

PPE, e.g. visors to prevent splashes entering the eyes and mouth.


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Figure 15: Contaminated Waste Disposal


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Effects of Pollutants on Human Health

The health effects associated with pollutants may be acute(i.e. immediate and short-

term) or chronic(i.e. long-term). They can also be caused directly or indirectly.

Direct Effects

Workers can be exposed to pollutants directly by different routes or contaminantpathways. These are:

inhalation:by breathing in the substance. Contaminants, such as micro-organisms or dusts and fibres such as asbestos, can be inhaled when landand / or badly sealed waste containers are disturbed.

Gases can also be released from fires, for example fires in waste skips, i.e.combustion products, or from landfill sites, e.g. landfill gas, which contains ahigh proportion of methane.

ingestion: by eating the substance. A good example of this is eating dustand other particles deposited on plants from vehicle emissions, althoughwashing may reduce this. Children are particularly sensitive to pollutantssuch as lead.

According to a 1995 World Bank study, contaminated water (lack of cleandrinking water and sanitation) causes about 80% of the diseases indeveloping countries, kills about 10 million people annually, and an average

of 27,000 premature deaths per day, more than half of them children underthe age of 5.

skin contact:some materials, by direct contact, can irritate the intact, i.e.unbroken, skin or even be absorbed through skin, e.g. phenols and coal tars.Some of these materials are also carcinogenic.

injection: materials that cannot get through intact skin can be carried throughthe skin via puncture wounds and cuts for example from old drums.Demolition and landfill site workers are at particular risk.

Indirect Effects

These include:

1. Air pollution.

2. Water pollution.

3. Land pollution.

Air Pollution

Two of the most significant global environmental issues are associated with airpollution.


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in Brazil, was an agreed framework on climate change, which recommendeddeveloped countries to:

take appropriate steps to significantly reduce emissions of greenhouse gasesand especially carbon dioxide;

help developing countries reduce their emissions of these gases;

compile inventories of emissions; and

produce and publish national programmes to limit emission and to promoteboth research and public education with regard to climate change.

In December 1997, an agreement was made at Kyoto in Japan and gave rise to theKyoto Protocol. The Kyoto Protocol aims to reduce greenhouse gas emissions by

setting legally binding emissions reduction targets for developed countries. TheProtocol establishes different emission reduction targets for different countries andallows emissions trading between countries to enable them to meet their final targets.

Depletion of the Ozone LayerFigure 17: The Earths Atmosphere

Ozone is a molecule containing three oxygenatoms (O3). It is a highly toxic and irritant gas,which is blue in colour and has a strongpungent odour, unlike the colourless andodourless normal oxygen molecule (O2),which has two molecules.

The earths atmosphere is divided into severallayers. The majority of atmospheric ozone isfound within the stratosphere, between 15 and30 km above the earths surface.

The ozone layer acts as a shield, protectingthe earth from the harmful effects of solarradiation. In particular it filters out some of the ultra-violet radiation known as UVB.

Researchers have now identified numerous ozone depleting substances (ODS), themost notorious of which are chlorofluorocarbons (CFCs), which were widely used asrefrigerants, propellants, solvents and foam blowing agents in the latter half of thetwentieth century. Other ozone depleting substances include methyl chloroform,carbon tetrachloride, methyl bromide, and halons.

The effect of the ozone depletion can be clearly seen in the ozone hole overAntarctica, which has been visible every spring since the 1980s. It is not literally ahole, rather an area of the stratosphere where the ozone levels are considerablylower than normal. In some years, there has been a decrease of more than 60%from expected levels.

Reduction in ozone levels has lead to an increase in the levels of UV radiationreaching the earths surface. Whilst small quantities of UV radiation are essential for


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human health, e.g. in the manufacture of vitamin D, and various hormones, in largerdoses it leads to adverse effects such as burns and skin cancers. Plant life can bedamaged due to interference with germination processes. Marine eco-systems maybe thrown into serious imbalance due to the effect of UV radiation on phytoplankton.Synthetic materials can also be adversely affected.

The Montreal Protocol was signed in September 1987, with the specific aim ofprotecting the stratospheric ozone from further damage, allowing it ultimately to healitself. It currently provides clear steps for the phasing out of certain ozone depletingsubstances. However, the long life of these substances in the atmosphere meansthat full recovery of the ozone layer is unlikely before 2050 (Source: EuropeanEnvironment Agency).

Water Pollution

Water pollution can occur directly or indirectly, for example due to run off fromchemical storage areas, road traffic accidents or the escape of leachate (waterhaving percolated through the material, bringing contaminants with it) from landfillsites. Some organic materials, especially those based on phenol can pass throughplastic water pipes, thus contaminating the water. If the water inside the pipe ischlorinated water, this can produce chlorinated phenols. Chlorinated phenols areeven more difficult to taste or smell than phenols but are more toxic!

Other materials, like the famous pesticide DDT, can bio-accumulate (build up in livingmatter) in the bodies of filter feeders such as shellfish and then cause harm tohumans and wildlife when the shellfish are eaten.

Land Pollution

Particles of contaminated soil may cause direct health problems if handled oringested by adults and particularly by children. Both particulate matter and vapourscan also be inhaled, notably when the land is disturbed.

Indirect effects can also occur, for example vegetable gardens located on pollutedland may produce crops which have been contaminated by the direct uptake oftoxins or the deposition of contaminate particles on the growing crops.

Cadmium is a heavy metal, which causes hypertension at levels below thoseregarded as toxic. Long-term exposure leads to itai-itai disease, which ischaracterised by severe joint pains and eventual immobility due to skeletal collapseas excess cadmium leads to bone porosity and inhibition of bone repair mechanisms.

Abnormally high levels of cadmium have been found in the kidneys and livers ofsheep grazing on pasture fertilised for years with sewage sludge (Source: MWilkinson and J Hill, Lambs liver with cadmium garnish, New Scientist, 22 March1997, p.4).

It is also important to remember that certain wastes, if mixed together, can react toproduce new materials that may be much more dangerous than the original wastes.

For example, in December 1982 a landfill site containing firework waste nearEdinburgh in Scotland exploded. It is believed that this was the result of the


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exothermic reaction between magnesium, a common constituent of fireworks, andwater, which produced hydrogen.

Managing Waste

If organisations wish to minimise the waste produced by their activities and improvetheir process efficiency, they must understand why and how wastes are producedand what can be done to minimise and, where possible, eliminate them. However, itis important to remember that waste is produced across all the activities of business,for example in offices, canteens, vehicle maintenance facilities, laboratories,warehousing and retail outlets as well as in production and manufacturing processes.

Legislative Controls

Most countries now have legislative controls on the management of waste. Forexample, the Waste Framework Directive 91/156/EEC requires every EU MemberState to produce a statutory waste management plan. The core aims of this plan areto:

ensure that waste is managed without endangering human health or harmingthe environment;

to provide an integrated and adequate network of waste managementinstallations so that waste can be disposed of close to its point of production(i.e. the so called proximity principle) with each Member States waste disposal

capacity meeting its own needs, although waste for recovery and recycling isallowed to move freely between the Member States; and

to promote waste reduction, reuse and recovery so that waste is moved up thewaste hierarchy.

Waste Hierarchy

DISPOSEDISPOSE

RECOVERRECOVER

RE-USERE-USE

REDUCEREDUCE

PREVENTPREVENT


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The aim of all pollution control regimes should be to minimise and, where possible, toprevent the release of substances which are potentially harmful or polluting to theenvironment.

There are two main classes of pollution control:

control at sourcewhere the process itself is considered and modifications orchanges made to reduce the productions of pollutants; and

control at the point of effectwhere the end of pipe solution is considered,i.e. the production of pollutants is allowed and then the treatment is appliedbefore emission to air, land or water. This is obviously a less preferableoption than control at source.

There are four key steps to controlling pollution at source. These steps form a

hierarchy and are:

1. Reformulate the product, e.g. develop a non-polluting or less-pollutingproduct or process by using different raw materials or feedstocks.

2. Modify the process, e.g. change the process to control by-product formationor to incorporate non-polluting raw materials.

3. Change the equipment, e.g. make the equipment more efficient or allow it touse by-products from another process.

4. Recover resources,e.g. recycle by-products for own use or use by others.

Wastes produced by one activity can be raw materials for another. In largeintegrated chemical plants, reuse of materials in this way is normally aninherent part of the design.

There are instances where one companys waste materials can be of use to anothercompany. For example oil is widely recovered from oily wastes and reused. Rubberis increasingly being reclaimed from scrap tyres by means of shredding andcrumbing and being re-used in manufacturing a range of products, including carpetunderlay as well as being used as a fuel in purpose built facilities.

Energy recovery is also possible in many modern incinerators. Virtually all organic

compounds have an energy content that can be utilised if they are burnt underappropriate conditions. It is generally better to recycle solvents than to burn them forenergy production as their manufacture uses more energy than can be recovered byburning and their selling price allows a profit to be made.

Significant environmental problems may also arise when waste is burnt. Forexample, hydrogen chloride or dioxins may be produced.

If waste cannot be reduced, reused or recycled then the only options left aretreatment or disposal.


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key materials and the associated generation of waste.

The following information should be obtained from this process as aminimum:

the quantity of each waste produced over a reference period, e.g.litres, kilograms, tonnes per day, week, month or year. These mayhave to be estimated, for example based on the weight of anaverage skip load of that type of solid waste or the average numberof full drums of that particular liquid waste sent for disposal perannum;

the activity or activities producing each type of waste;

the composition of each type of waste including its physicalproperties, e.g. solid, sludge or liquid, chemical properties, e.g.flammable, corrosive, toxic, etc., or other special considerations, e.g.

whether it is putresible (can be rotted) perhaps to form compost; and the way in which the waste is categorised on site.

Step 5: True cost of wasteis always much higher that just the cost of disposaldue to the hidden costs such as stock losses, disposal costs, the cost ofthe plant and equipment to handle the waste and PPE.

Step 6: Prioritising issues, i.e. everything cannot be done at once. Prioritiesshould be ranked in terms of cost, ease of implementation, capacityconstraints, risk reduction and of course environmental benefit.

Step 7: Problem solving and options for improvement, i.e. using techniques

such as root cause analysis and brainstorming.

Step 8: Opportunity assessment, i.e. assess the technical and economicfeasibility and the environmental impact of the solutions identified in theprevious stage.

Step 9: Implementation and maintaining momentum, e.g. by writing a carefullystructured action plan, involving staff at all levels and involving customersand suppliers.

Segregation of Waste

Waste should be segregated into the relevant different categories as close aspossible to the source of waste generation, to avoid secondary handling, which mayinvolve health and safety risks as well increased operational costs. Clearly identifiedcollection points should therefore be identified for each of the categories in the wastestream. It is vitally important not to mix waste streams as:

certain wastes may react with each other giving rise to a serious event withboth health and safety and environmental implications;

the mixing of even small quantities of hazardous with non-hazardous wastenormally makes the whole consignment hazardous in the eyes of the law and

thus subject to additional stringent and expensive requirements;


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the mixing of non-inert waste with inert waste for landfill will make all thewaste non-inert and therefore may be subject to a higher rate of landfill tax;

waste for different disposal routes is clearly identified, more effectivelyhandled and efficiently dispatched to the correct repressor or disposal facility;and

data collected and the completion of all relevant paperwork, legal andotherwise is made simpler and quicker.

In addition, all waste in containers should be in appropriate secure, properly labelledcontainers. The containers should also be stored in a manner that minimises the riskof vandalism or of the unauthorised deposit of waste, e.g. by members of the public.

A nominated individual should have overall responsibility for waste management for a

given area or activity. There should be simple but effective procedures to ensure thatthe risks of pollution are minimised and, where possible prevented. All thoseinvolved in the management of waste should have received appropriate training thatspecifically includes storage, segregation, handling controls, the duty of care, recordkeeping and the need for regular, relevant inspections and audits.

There are ten simple rulesfor waste storage which are outlined below:

1. ensure the storage area is of sufficient size and is suitably located, i.e. awayfrom drains, water courses, etc.;

2. clearly label the storage area, and individual containers to advise of contentsand hazardous properties;

3. ensure the storage area is secure and protected from accidental or maliciousdamage;

4. if necessary protect the storage area with bunds and rainwater collectionsumps to minimise the risk of water pollution;

5. store different waste types separately to avoid confusion;

6. never store incompatible wastes together;

7. select the appropriate container for the waste and ensure it is in goodcondition;

8. keep quantities of waste and storage times to a minimum;

9. protect the waste from the elements (sunlight, rain and wind) if necessary;and

10. do not dispose of unusual wastes in a general waste skip.


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ReferencesILO 1993 Safety in the Use of Chemicals at Work (ILO Code of

Practice)

ILO 2001 Ambient Factors in the Workplace (ILO Code of Practice)

HSE 1993 HSG 97: Step-by-Step Guide to COSHH Assessment

HSE 1993 HSG 37: An Introduction to Local Exhaust Ventilation

HSE 1998 HSG 53: The Selection, Use and Maintenance of RespiratoryProtective Equipment


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Notes


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Notes

nebosh igc2 part 4

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