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Publications
Griffith University and the Department of the Environment, Sport & Territories, 1997
ISBN 0 868 57655 7
This workshop focuses on the basic concepts of risk assessment and management of chemicals in the home, workplace and the environment. All chemicals, even naturally occurring ones, are potentially toxic but once the degree of risk is assessed, management strategies can be developed to minimise the possibility of harm from exposure to chemical.
During this workshop participants will:
Participants' understanding of risk and hazard is highlighted by a brainstorming activity. The workshop focus on chemical risk is outlined.
A mini-lecture defines the major terminology associated with risks, hazards and toxicity of chemicals.
Perceptions of risk and the degree of risk vary widely. A group discussion explores risk perception.
A mini-lecture outlines terminology and concepts such as dose response, exposure pathways and the duration and specificity of chemicals.
Participants work in small groups to explores consequences and alternatives to Endosulphan use in a Canberra case study.
A mini-lecture introduces risk assessment followed by a small group activity that explores chemical risk assessment in the home.
A group activity examines the key questions of risk management and explores how ordinary people deal with risks. Alternatives to toxic chemicals and their use are considered.
Arguments about risk management are hardly ever black and white. A number of statements about chemical risk are debated from pro and con points of view in a group activity.
An activity that examines the likely success of using risk assessment (Activity 6) as a teaching strategy in the school classroom and grounds.
Overhead Transparency Masters OHT 1: Risks Associated with Common Activities
OHT 2: Perceptions of Risks
OHT 3: Chemical Risk Questions
OHT 4: Key Questions in Risk Management
OHT 5: Using Alternatives
Resources
Resource 1: Terms and Concepts of Risk
Resource 2: Chemicals and Human Response
Resource 3: Endosulphan: A Case Study
Resource 4: Problems and Solutions Worksheet
Resource 5: Assessment of Risk
Resource 6: Lists of Hazardous Chemicals and Their Sources in the Home and School
Resource 7: Chemical Risk Worksheet
Resource 8: Risk in the Home
Resource 9: Safer Alternatives to Hazardous Chemicals in the Home
Australian Consumers' Association (1991) How Safe is Our Food? A Choice Book with Random House, Australia.
Canter, L. W. and Knox, R. C. (1985) 'Risk Assessment as Related to Aquifier Restoration Planning', Ground Water Pollution Control, Lewis Publishers Inc., USA.
Committee on the Institutional Means for Assessment of Risks to Public Health, Commission on Life Sciences, National Research Council (1983) Risk Assessment in the Federal Government: Managing the Process. National Academy Press, Washington DC.
Cothern, C. R. (1987) 'Techniques for the Assessment of Carcinogenic Risk Due to Drinking Water Contaminants', CRC Critical Reviews in Environmental Chemistry, vol. 16, no. 4, pp. 357-399.
Parish, P (1987-89) Medicines - A Guide for Everybody, Sixth Edition, Penguin Books.
Pease, W. S., Zeise, L, and Kelter, A. (1990) 'Risk Assessment for Carcinogens Under California's Proposition 65', Risk Analysis, vol. 10, no. 2, pp. 255-271.
Rodricks, J. V. (1992) Calculated Risks, Cambridge University Press
Salminen, S., Ahokas, J. and Donohue, D. (1991) Safeguards - An Australian Guide to Hazardous Home Chemicals, McPhee Gribble.
Ask participants to brainstorm a list of risks and hazards we are exposed to in our everyday lives. Answers may include earthquakes, fires, cyclones, severe cold or heat, chemicals, smoking, drugs, alcohol, car accidents, drowning, and murder.
Collate these into two lists on a white board, under the headings: natural risks and human-induced risks.
Show OHT 1 to promote discussion. Explain that this workshop is focusing on the risks associated with chemicals in common use in homes or schools.
Present a mini-lecture based on Resource 1 defining the major terms associated with risks, hazards and toxicity of exposure to chemicals.
Display OHT 2 and conduct a discussion with participants. Ask: Do you agree with the points? Would scientists and chemical engineers agree with you?
Present a mini-lecture using Resource 2 on the biological effects of chemicals and their specificity.
Present a mini-lecture outlining the use of Endosulphan to treat lawn grubs on the lawns of Parliament House using Resource 3.
Ask participants to form small groups. Distribute copies of Resource 3 to all participants as well as two copies of Resource 4 copied as OHTs for each small group.
Ask half of each group to fill in their OHT charting the consequences of the use of Endosulphan in the case study in Resource 3. Ask the other half of each group to decide on an alternative to Endosulphan, and to fill in their OHT, charting the consequences of using alternatives.
Ask some of the groups (presenting both viewpoints) to present their consequence charts to the whole group for comment.
Present a mini-lecture introducing the concept of risk assessment using Resource 5.
Distribute copies of Resource 6, Resource 7 and Resource 8 to participants. Working in small groups, ask participants to list all rooms or locations where chemicals are found or used in the average home. Remind them that foods and naturally occurring chemicals (such as herbs and natural medicines) can be included as well as the synthetic ones.
Ask pairs within each group to identify and list the topics outlined on OHT 3.
Allocate two or three common household chemicals to each group. Ask participants to classify each one using the risk concepts in Resource 7.
Ask groups to assess the risk (e.g. high, moderate, low, negligible) for each age group, of a toxic effect being observed for each of the chemicals chosen.
To conclude, ask groups to draw a graph to compare the risks associated with various chemicals for each age group and to then develop a statement about the risk posed by each chemical.
Outline the key questions of risk management using OHT 4 and then raise the question: How do we citizens deal with the risks we assessed in Activity 6?
Brainstorm responses to this question and list these on a whiteboard. Answers should include: remove, reduce, provide alternatives, increase labelling, advertising campaigns, education campaigns and increased research.
Distribute copies of Resource 9. Working in pairs, ask participants to consider the alternatives using questions on OHT 5.
Working in small groups, ask participants to develop two minute arguments for and against the following topics:
Each group then presents their debates to the whole group.
Ask participants to evaluate the likely success of using risk assessment as in Activity 6 as a teaching strategy in their own school classroom and grounds. Ask:
Conclude with a group discussion sharing participant answers.
The public perceives that a chemical product - or its manufacturing process has a greater risk than the risk estimated by experts (such as scientists) when:
If community perceptions and fears are ignored or not understood by the risk-analysis communicators, then the information they provide will be ignored by the citizens concerned.
Identify and list:
Risk
There are two definitions of risk in common use. However, there are several which are used generically by lay persons and the media. Context will often indicate which definition is most appropriate.
Risk can be defined as the probability that some harmful event will occur. Because it is a probability, risk is expressed as a fraction without units with values from 0 to 1.0. Zero risk implies that there is absolute certainty that no risk exists - a degree of certainty that can never be proven. A value of one corresponds to absolute certainty that the risk will eventuate. If we say that there is a lifetime cancer risk from a particular carcinogen of one in 100,000 (0.00001) at a stated average daily dose, then it means that one person out of every 100,000 people receiving that daily dose will develop cancer from that carcinogen. Society's fear of chemicals and cancer has become so great that the risk of 0.00001 (1 in 100,000) instantly creates cries of outrage against such chemicals. To put these risks in context consider the risks associated with common activities as listed (Rodricks pp. 184) Shown in OHT 1.
The data presented on OHT 1 are similar to those derived for Australian conditions. It should be noted that these data are readily obtained from accident and mortality data obtained by hospitals and medical practitioners and are reasonably accurate. Similarly, data related to the risks of swallowing concentrated chemicals are fairly accurate because most people who get sick from such causes are recorded in medical records with the chemical specified as the cause of their illness. It is much more difficult to obtain reliable data of the risks associated with environmental chemical exposures.
A second definition of risk combines probability of an adverse effect from a substance or organism with the magnitude of the consequence of that adverse effect. This definition implies multiplication of the probability and the magnitude to provide a numeric value.
Both definitions contain at least a qualitative acknowledgement of the magnitude of an effect which is likely to occur.
Hazard
Hazard relates to the potential harm that can occur from a specific chemical or activity. Diving into shallow water, smoking and taking unprescribed drugs are activities that are considered hazardous. With chemicals, hazard is directly associated with the toxicity or carcinogenicity of the substance. For example, the US National Academy of Sciences states that pesticides account for 2.1% of all US deaths from cancer every year.
Toxicity
All chemicals, natural and synthetic, are toxic - that is they produce adverse health effects - under some conditions of exposure. The common reference to some chemicals as toxic and others as non-toxic is therefore incorrect. Many chemicals are essential to life itself, but under some conditions, or in cases of very high doses, cause sickness or death.
Other chemicals where a relatively high dose can be consumed from, for example, a bottle of concentrated pesticide are also considered very toxic. In such cases, it should be noted that in solvent-based formulations it is quite possible for the solvent to be a major contributor to the toxicity of the substance. Even where the solvent itself is not particularly toxic, its action can be synergistic, i.e. the overall toxicity of the pesticide with the solvent is greater than from either chemical on its own. In the particular case of solvents, even water based, the presence of surface active agents (surfactants) which increase solubility or provide surface wetting when the pesticide is applied, can increase the toxicity. The surface active material assists the pesticide pass through skin and protective layers into the blood stream or sensitive tissues protected by the skin.
Dose Response
Chemicals differ as to the level of exposure at which toxicity becomes apparent. The conditions of exposure - dose and duration of dose - determine the 'toxicity'. In some cases, a relatively small, single dose can cause death to the exposed individual or animal . The botulinum toxin which is produced from a bacteria associated with food poisoning is very toxic as are the chemicals from many Australian poisonous snakes.
A very important factor in considering hazard is the body weight of the exposed individual. Many toxins accumulate in, or are selected to target, specific organs of the body. It is the effective concentration at the sensitive site that is important in measuring 'dose'. For infants and small children, the low body weight means that a dose which is harmless to adults can be toxic to the child because of the high concentration that occurs at a sensitive site. (Refer to different dose rates and administration advice on Panadol and Codral cold tablets for example.)
Exposure Pathways
For toxicity to be exhibited, exposure must occur, i.e. the organism must come into direct contact with the chemical. In some cases, general exposure in itself is not sufficient; specific body organs must be directly exposed to the chemical. The pathway of exposure is therefore also of importance. (Some writers separate pathways from routes, where pathway relates to the media which transport the chemical to the immediate environment of the person or organism. The 'route' of exposure then refers to the route by which the chemical actually enters the body. 'Pathway' in this text will encompass both.) The major pathways of human exposure are through the nose and lungs (air pollutants); mouth (liquid and solid toxins, e.g. tablets, water contaminants, pesticides); skin absorption (liquids and vapours, e.g. pesticides, petroleum hydrocarbons).
Many of these same pathways apply to other species exposed to environmental contaminants.
Exposure Duration
With highly toxic compounds, a single dose can produce adverse impacts in the target organism. Chronic exposure to lower doses can sometimes produce toxic effects - particularly if the chemical accumulates unchanged within an organ such as the liver or kidney. In other cases, chronic exposure results in an accumulation within fatty tissue or muscle. In such instances, toxic effects are seldom manifested despite relatively high apparent doses. This is the circumstance that applies particularly to many fat soluble pesticides which humans consume in very low levels in their foods.
Aquatic organisms are particularly subject to higher doses than expected through bioaccumulation of some chemical contaminants from the water in which they live. Continued exposure over a period of time allows high levels of chemical to accumulate in selected tissues, e.g. fat and liver organs.
One area of concern for humans has been the exposure of babies to low doses of chemicals from mothers' milk during breast feeding. The fact that this milk makes up the entire food supply for the baby and that it has a high consumption relative to its small body weight has raised concerns that chronic toxic effects may occur.
An important principle in reducing risk from chemical exposure is to ensure that a varied diet is consumed to maximise dilution of any chemical intake. Exposure should be minimised wherever practical.
Specificity
A further factor often overlooked in considering toxicity, and therefore risk, is the specificity of the chemical toxin. Pesticides, for example, are selected because they are selective in the species they attack. Some pesticides are selected because they attack weeds (herbicides) while largely leaving unaffected the crops growing beside the weeds. Pharmaceutical drugs are selective to humans and or mammals or bacteria affecting humans. Many are therefore relatively harmless when they come in contact with other species.
However, there are other instances where non-target organisms are very sensitive to a particular chemical.
The chemical Endosulphan provides a good illustration of the complexity of some risk and hazard assessments.
Endosulphan is highly toxic and specific for the heliothis moth that attacks cotton. It has a reasonably high mammalian toxicity associated with relatively high doses of the concentrate (measured in percent by volume). However, if used in accordance with instructions on the labels, it is quite safe. In contrast, a storm after treatment of cotton can result in water concentrations of Endosulphan of less than one part per million. Fish can be killed by concentrations as low as 0.001 ug/gm, i.e. one part per billion. There appears to be few other aquatic organisms seriously affected by the chemical in water running off treated cotton fields.
Similarly, Endosulphan is commonly used to treat lawn grubs. In a recent case, the lawns of Australia's Parliament House were treated with this chemical to eradicate a plague of lawn grubs attacking and killing off the luscious, well-groomed and fertilised lawns which are in front of Parliament House. The grubs died in their thousands only to provide a major feast for the local bird population. Many of the birds ate sufficient grubs to accumulate a relatively high dose of Endosulphan over a short time. Many birds died. The public outcry that resulted produced concerns of high risk to humans! Quite unnecessarily, this created fear in some members of the public. Not only were the levels of pesticide quite low, the likelihood of consumption of the grubs by humans was quite low, i.e. the risk of exposure even to children was too low to be of real concern. Concerns for bird life were in contrast legitimate. These examples indicate the need for care and risk assessment in the use of farm and garden chemicals.
Risk analysis involves identifying hazards, evaluating the nature and severity of risks (risk assessment), using that and other information to determine options and make decisions about reducing or eliminating risks (risk management), and communicating information about risks to decision-makers and the public (risk communication). Formal risk assessment is difficult, imprecise and even controversial. The more complex a system or chemical reaction, the more difficult it is to calculate risks. However, we can all attempt some assessment of the risks of chemicals in our workplaces and see if we can put into place some risk management techniques. To assess the risk of toxic effects arising from a particular chemical the following information is necessary:
All three of these need to be understood before a statement about the risk posed by a particular chemical can be made.
(Note the following list is not exhaustive.)
| Chemical | Common Source |
| lead | car batteries, old paint, leaded petrol, car exhaust fumes, solder |
| cadmium | printing inks and dyes (yellow) |
| mercury | thermometers, dental amalgams |
| copper | pool algacides |
| zinc | galvanised steel, food 'tins' |
| aluminium | saucepans, drink cans |
| organophosphate pesticides | diazinon, endosulphan, 'endogrub' |
| borax | ant kill |
| glyphosphate | 'zero' weed killers |
| paraquat | herbicide (very toxic) |
| chlorine | 'Milton', pool chemical, bath cleansers |
| ammonia | 'cloudy ammonia', bathroom cleansers |
| ethyl alcohol | wines and spirits |
| methyl alcohol | methylated spirits |
| caffeine | coffee, tea, cola drinks |
| sodium hydroxide | 'Drano', caustic soda, bathroom cleansers, dishwashing detergents |
| sulphuric acid | lead batteries |
| hydrochloric acid | pool chemicals, soldering flux |
| acetic acid | vinegar |
| formaldehyde | chipboard, carpet glues |
| asbestos | old fibro, brake pads |
| nitric oxides | car exhaust fumes |
| ozone | photocopiers |
| benzene | petrol |
| acetone | nail polish and remover |
| organic solvents | glues |
| aflatoxin | peanuts, peanut butter |
| ciguatera | some fish exposed to certain algae |
(Readers are referred to the reference - Safeguards - An Australian Guide to Hazardous Home Chemicals, by Salminen et al. It should also be noted that all chemical substances are potentially hazardous /toxic if the dose is sufficiently high.)
Chemical: ____________________________
Use one table for each chemical
| Age Group | Accidental or deliberate exposure | Exposure Risk 1=low 5=high | Perception of Toxicity 1=low 10=high |
| Baby | |||
| Family Toddler | |||
| Visiting Toddler | |||
| Family Children | |||
| Visiting Children | |||
| Teenagers and Young Adults | |||
| Parents | |||
| Elderley |
Instructions: Identify whether, for each group, exposure is likely to be accidental or deliberate. Consider whether accidental exposure is likely to be affected by age. For selected age groups (e.g. toddlers, children, teenagers/parental age groups, elderly) identify a selection of well known chemicals to which exposure risk ranges from high to low (assign numerical values of 1 to 5 with 5 being high risk of exposure).
For this same selection of chemicals, allocate a position on a scale of 1 to 10, the perception of the acute toxicity of each chemical e.g. caustic soda in drain cleaner is likely to be rated near 10. 'Alcohol' is likely to be rated 3 or 4 because most association is with diluted alcohol such as in beer and wine. (High concentration alcohol mixtures should be recognised as highly toxic because of the primary metabolite - formaldehyde.)
Source: Draft 2, Risk Assessment and Management of Chemicals, p. 19
Source: Salminen, S., Ahokas, J. and Donohue, D. (1991) Safeguards: An Australian Guide to Hazardous Home Chemicals, McPhee Gribble.
| Type of Effect | Possible Cause | Sources of Exposure |
| Immediate | ||
| Dermatitis (allergic or irritant) | chromium, nickel, fibreglass, epoxy resins (glues), solvents, soaps and detergents, caustic alkaline compounds | housekeeping, plastics, contact with nickel or chromium in clothes, (buttons, etc) |
| Headaches | solvents, carbon monoxide, household cleaning agents, air fresheners | dry cleaning, car exhaust fumes, painting, wood finishing |
| Irregular heartbeats | solvents, fluorocarbons | solvent use, leaking refrigerator or air conditioning apparatus |
| Psychoses | organic lead, mercury, carbon disulphide | petrol handling, fungicides, wood preservative |
| Long term | ||
| Behavioural changes | lead, arsenic, mercury, solvents | solvent usage, exhaust fumes, petrol, contaminated foods, dental amalgam (seldom) |
| Chronic bronchitis | cigarettes, cadmium, dusts, solvents | smoking, solvent and paint usage |
| Lung cancer | cigarette smoke, asbestos, uranium | smoking, uranium mining, pipe fittings (with asbestos exposure) |
| Plant | Effects When Eaten |
| Angel's trumpet | any part of the plant may cause vomiting, convulsions and restlessness |
| Foxglove | source of a powerful heart drug, can cause heart problems, nausea, diarrhoea and vomiting if any part is ingested |
| Glory lily | any part can cause stomach problems and even neurological disorders |
| Lily of the valley | all parts poisonous when eaten, cause vomiting and diarrhoea (forms poisonous green and red berries after blossoms) |
| Monkshood | any part may cause respiratory problems |
| Oleander | all of plant poisonous, causes vomiting and convulsions |
| Poinsettia | the sap is poisonous and can be irritant to the eyes and skin |
| Poison ivy | can cause severe skin damage and dermatitis |
Source: South Australian Waste Management Commission.
Household hazardous substances can be greatly reduced by introducing safe substitutes in day-to-day activities. Most of these safe substitutes are cheap and can be home made. By giving more attention to ventilation, cleanliness and good sanitation, you can substantially reduce the use of most of the household hazardous substances. The substitutes mentioned below may not be as potent as the hazardous chemicals used, but should be effective for household use.
| Alternative To ... | Try |
| Air Freshener | Ventilation. Set vinegar out in open dish. Simmer cloves and cinnamon in boiling water. Open box of baking soda in refrigerators or closets. |
| Disinfectant | Mix half cup borax in 4.5 litres of hot water. |
| Drain opener | Prevent clogging with drain strainer. Use plunger. Flush with boiling water, quarter cup baking soda and 60ml vinegar. |
| Aerosol Sprays | Choose non-aerosol containers such as pump spray, roll-on or squeeze bottles. |
| Chemical Fertilisers | Compost is a good soil conditioner and can be made from grass clippings, food scraps and manure. |
| General Cleaner | Mix of baking soda in water. Hot water, soap and borax. |
| Surface Cleaner | Mix of vinegar, salt and water. Baking soda and water (half cup per bucket); doesn't work on aluminium. |
| Stubborn Spots | Rub with half lemon dipped in borax - rinse, dry. |
| Mould and Mildew | Concentrated solution of borax or vinegar and water. |
| Polish Brass | Use Worcestershire sauce. Use 50/50 mix of salt/flour with little vinegar. Use water in which onions have been boiled |
| Polish Silver | Soak in boiling water with baking soda, salt and piece of aluminium. |
| Polish Copper | Lemon juice or hot vinegar and salt. |
| Shine Chrome | Rub with newspaper, or rubbing alcohol, or white flour in dry rag. |
| Clean Linoleum Floors | Solution of 1 cup white vinegar mixed with 9 litres of water. |
| Wood Floors | Soapy water to clean and soft cloth to shine. |
| Clean Rug/Upholstery | Dry cornstarch sprinkled on surface, vacuum up. |
| Remove Spots | Soda water, lemon juice or salt. Immediate cold water. Cornmeal and water paste, brush when dry. |
| Floor/Furniture Polish | 1 part lemon juice, 2 parts olive or vegetable oil. |
| Paint and Stains | Latex or water-based paints are the best choice. Clean up does not require paint thinner. |
| Paint Remover | Use heat gun and scraper to remove paint (be sure to wear proper protective gear). A strong TSP (Tri Sodium Phosphate) solution (100 gram per litre) may work well. Brush on, wait 30 minutes, then scrape off. |
| Laundry Bleach | Half cup sodium hexametaphosphate per 20 litres of water. |
| General Bleach | Borax or washing soda. |
| Clean Windows/Glass | Mixture of vinegar or lemon juice in warm water. |
| Clean Oven | Baking soda and water. |
| Glues | Use water-based/starch-based glues. |
