Chlorine, pollution and the environment

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Chlorine is a naturally occurring substance. Its manipulation and use in forming artificial chemical products has had devastating effects on the environment which we are only now beginning to understand.

In its various artificial forms, chlorine plays a major role in the most pressing environmental problems which we face today; depletion of the ozone layer, global warming and acid rain. The pollution cau sed by its widespread use has been linked to a variety of serious health effects; poisonings have occurred in the chlorine industry since its inception and chlorine compounds have accumulated in the bodyfat of animals and humans.

Chlorine can exist safely, in the form of common salt (sodium chloride), for example, but the process of splitting common salt into caustic soda and chlorine gas makes it become dangerously toxic. One million tonnes of chlorine is produced from salt in this way every year in the UK. Most of this is combined with chemicals containing carbon to form organochlorines.

Organochiorines are contained in many of the familiar products we see in our shops, such as in solvents, pesticides, plastics, disinfectants, forms of packag ing and bleached pulp and paper products. If a product shows a list of its ingredients, any word containing the letters 'chloro' suggests the presence of an organochlorine. Many of the products which we buy are predominantly made of or encased in, plastics which contain chlorine such as PVC (polyvinylchloride). Some other plastics which do not contain chlorine stifl involve it at some stage in their production.

Polychlorinated biphenyls, (PCBs), chlorofluorocarbons (CFCs) and DDT are examples of organochlorine compounds which, although banned or discredited, are still evident in our environment. PCBs and DDT accumulate in the bodyfat of fish, animals and ultimately humans, through the food chain.

The manufacture of organochlorines gives rise to many unintentional by- products. Many of these are likely to lead to the same kinds of problems as the organochlorines which have already been banned.

In making organochlorine products, highly toxic by-products such as dioxins are inadvertently made at the same time and accumulate in the same way as PCBs in our bodyfat and in the environment generally. Similar major pollution problems also arise when these chlorinated products such as plastics and solvents are burned or incinerated as rubbish. The resulting polluted air affects the surrounding area, falling on agricultural land and accumulating in the food chain, putting food such as dairy products at risk from high levels of dioxins.

Studies in the US have shown that the presence of dioxins and PCBs is linked to nervous system damage in babies, with effects on memory and co-ordination. WEN's report, Chlorine, Pollution and the Parents of Tomorrow assesses the levels of dioxins and PCBs in Britain and concludes that similar effects may be occurring in between 1% and 8% of babies in this country.

International bodies and scientific institutions worldwide are calling for chlorine phase-out. In February 1994, President Clinton announced a strategy for the phase-out of chlorine in manufacturing; many towns and cities in Europe have banned PVC and the amount of chlorine used to bleach paper has fallen dramatically over the last few years. Chlorine has such a huge presence in our industrialised society, but now awareness is leading to the development of alternatives.

UK sources of dioxins and furans


The burning of rubbish and metal reprocessing creates dioxins from the organochlorines in the waste stream. Municipal, hospital and toxic waste incineration Accidental fires and bonfires Metal extraction and reclamation Cars running on leaded petrol(a small but need less source because of organochlorine additives)


The manufacture of organochlorines produces dioxins. Pentachlorophenol(PCP) contains dioxin impurities, and so do 2,4,5-T and some other pesticides. The use of these pesticides in Britain is now very small, but PCP is still in widespread use everywhere as a wood preservat ive. Agent Orange, the defoliant used in Vietnam, contained large quantities of 2,3,7,8-TCDD, the most toxic dioxin.

The dioxins that arefound in our bodies in the UK come mainly from the burning of material containing organochlorines such as PVC and wood treated with PCP. The dioxins are actually created on particles of soot and dust which are then spread efficiently into the air as the hot gases rise from the fire. The airborne dioxins fall on fields over a wide area beyond the burning site, where animals such as cows eat grass and plants contaminated by them. The dioxins stick firmly to fat in the cow, particularly to the milk fat, and to the fatty part of the meat. Since they do not break down, the cow acts as a dioxin concentrator. This also appliesto otheranimals, and is the reason why animal fat is the major source of dioxins for humans. Dioxins in fish come partly from airborne particles falling on the sea, but also from industrial and sewage discharges. Sewage contains dioxins - partly originating from the use of PCP wood preservative in homes and wood treatment plants. Municipal incinerator ash is landfilled. The ash from incinerators and fires contains large amounts of dioxins, furans and other toxic substances. Pollutants released from the ash may reach the water supply.

Dioxins in the body

Dioxin masquerades as a hormone in human cell processes which is why it is so extremely potent. Dioxins influence the cellular DNA to produce a range of enzymes and hormones which control the growth and division of cells, with implications for birth defects and cancer. Unlike natural hormones, which are short-lived, dioxin's activity in the cell is difficult to switch off. The effects in this list have been demon- strated at higher than average exposures. However, present levels of dioxin contam ination in the general public are far higherthan before industrialisation. Also present are PCBs, some of which also have dioxin-like activity.

The US EPA expects more subtle effects, such as onthe immune system, to occur at the levels we now have in our bodies. Recent evidence suggests these effects could include endometriosis, a painful menstrual disease occurring in 10% of women.

Effects of dioxin-like compounds
Immune system damage, especially likely in children
Damage to liver, kidney and digestive tract
Miscarriage and sterility
Birth defects and behavioural changes in offspring
Nervous system damage

Chlorine Cartoon

Chlorine in swimming pools
The substance used to chlorinate swim- ming pools is usually a salt (sodium hypochlorite) which contains very little free chlorine. Organochlorines do occur inswimming pools, butthesedo not include the highly toxic dioxins. Levels of other organochlorines are higher in people immediately after swimming; and they also cause sore eyes. Better filtration and pool maintenance would reduce the amount of hypochlorite used.

MAIN FOOD SOURCES OF DIOXINS AND FLURANS Meat, dairy products and animal fats in other foods supply nearly all the dioxins in the average UK diet. Fish and eggs are smaller sources.

Chlorination of drinking water
The process uses chlorine gas and prduces smailquantities of organochlorines. A major statistical review of US studies has found that people who drink chlorinated drinking water are more likely to contract rectal and bladder cancer. Alternatives for purifying water such as ozone and ultraviolet radiation could be developed. Only 2.5% of the million tonnes of chlorine produced annually in the UK is used to disinfect drinking water.


Plastics are made up of chemicals joined together. Polyvinyl chloride (PVC) is made from vinyl chloride, one of many organochlorines derived from the action of chlorine on petroleum hyd rocarbo ns made from oil. Manufacture of these chemicals produces dioxins and other toxic waste. Links have been made between vinyl chloride and cancer and liver damage, found in PVC industrial workers. Vast amounts of vinyl chloride escape from PVC factories worldwide. ICI states that its Merseyside plant released 1200 tonnes of vinyl chloride into the at- mosphere in 1992. PVC may well be the main chlorinated material responsible for the creation of airborne and food-borne dioxins in the UK. The government's re- port "Dioxins in the Environment" states that PVC forms up to half the chlorine in UK municipal rubbish. Much of this is PVC in packaging and other short-life products. Municipal incinerators are by farthe largest known source of dioxins to the air in the UK. Hospital incineration is also a large source, because hospitals use PVC in 'disposable' equipment.

The Women's Environmental Network Guide to Dioxins, Chlorine and Organochlorides

"Dioxin and its chemical cousins have been administered, wholesale to everyone ...whether old, young, or not yet born; whether well or sick; whether they want it or not ... the entire chemical industry is in the drug business". (Dr. B. Commoner 2nd Citizen's Conference on Dioxin)

Chlorine is an element which has always existed on earth, but almost entirely in safe forms such as common salt. Trouble arises when common salt is split in order to make caustic soda, a useful industrial chemical, and elemental chlorine, which is a green gas used as a poison gas in World War I. Chlorine gas is now an important raw material in the chemical industry. Itis combined with organic (carbon) chemicals from oil and coal to make organochlorines. These include the plastic, PVC, many solvents such as drycleaning fluid, pesticides and wood preservatives such as entachlorophenol (PCP), and some disinfectants and drugs. Chlorine gas is also used to disinfect water, but this is a minor use. The use of chlorine to make chemicals increased enormously from around 1940. This is mirrored by a huge rise in dioxins in the environment.

What are dioxins?

Unless otherwise stated when we talk about dioxins we include dioxins, furans and dioxin-like chemicals, for example some of the now banned PCBs that were made for use as electrical insulators and in paints.
Dioxins are a type of organochlorine, containing carbon, hydrogen, oxygen and chlorine. They are unintentional by-products of chemical manufacturing proc- esses involving chlorine. They are also created when organochlorines such as PVC are incinerated or burned.

Why are dioxins a problem?

Dioxins masquerade as hormones in cell processes, which is why they are so toxic. They influence the cellular DNA to produce various substances which control the growth and division of cells, or alter other important chemical messengers. Unlike natural hormones, which are short-lived, dioxin activity in the cell is difficult to 'switch off'. Also, they last for years in our fat: it takes seven years for most people to even halve their levels of the most toxic dioxin, TCDD.

Effects of dioxin-like compounds
Immune system damage,
especially likely in children
Damage to liver, kidney
and digestive tract
Miscarriage and sterility
Birth defects and behavioural
changes in offspring
Nervous system damage
Reduced sperm count

From the air to our bodies

In the burning process the dioxins are actually created on particles of soot and dust. They are then spread efficiently into the air as the hot gases rise from the fire. The airborne dioxins fall on fields over a wide area beyond the burning site, where animals such as cows eat grass and plants contaminated by them. The dioxins stick firmly to fat in the cow, particularly to the milk fat, and to the fatty part of the meat. Since they do not break down the cow acts as a dioxin concentrator. This also applies to other animais, and is the reason why animal fat is the major source of dioxins for humans. Dioxins in fish come partly from airborne particles falling on the sea, but also from industrial: and sewage discharges. Incinerator ash containing large amounts of dioxins is landfilled and so its pollutants can re-enter the environment.

Intakes and levels of dioxins

Most industrialised countries have similar levels of dioxins in the general population. The levels of dioxins in bodyfat are governed by the daily intake from food. The US EPA estimates that Americans have 60 parts per trillion (ppt) of dioxin-like compounds in their bodyfat, a concentration of 9 ppt in the whole body. A recent study in Wales found around 60 ppt without including PCB's, so UK levels could be higher than those inthe US. Surveys of breastmilk also suggestthat UK dioxin levels are among the highest in the world.

Within the general population, some people will have relatively low intakes of dioxin, and some will receive higher than average doses because of their diet (fatty foods), living near to dioxin sources (like Coalite in Der- byshire) and exposures at work. The United States Environmental Protection Agency says "Some more highly exposed members of the population may be at risk ... of decreased sperm counts, higher probability of experiencing endometriosis in women, reduced ability to withstand immunological challenge, and others."

Dioxin Sources

All processes involving chlorine and heat are likely to produce dioxins to some extent, but airborne dioxins are the main source of dioxins in ourfood in the UK. Contamination by organochlorines such as solvents, PVC and PGP wood preservative is so general that many kinds of buming produce dioxins. The leaves of trees absort, organochlorines from the air, and cigarettes contain pesticides from tobacco and residues from chlorine bleaching of cigarette paper. However, all these sources will be reduced and eventually eliminated as we stop using chlorine.

It is sometimes said that known sources only account tora small proportion of the total dioxins created each year, but the enormous uncertainty in the amounts from each source could easily account for this. In 1993 the US EPA made an estimate for dioxin Production from municipal incinerators, but this has since been exceeded by the measured emis- sions from one incinerator. This suggests that the only safe course is to eliminate air known sources.

Major Airborne Sources:
Municipal waste incineration
Hospital waste incineration
Other incineration: chemical, industrial, cremation etc
Metal reprocessing
Other Airborne Sources:
Accidental fires, bonfires and builbing site fires and oil and coal burning
Cement kilns which burn hazardous waste
Use of leaded petrol
Chemicals and Chemical Processes:
Chlorine bleaching of wood pulp
Manufacture or chlorine gas.
Production of PVC plastics, chlorinated solvents, pesticides and other chemicals
Metal extraction processes which use chlorine (mainly not airborne sources)


End incineration. unecessary and severely polluting examples should be closed immediately and others timetabled for closure as soon as possible Begin the planned phase out of chlorine as an industrial raw material, starting with bulk processes such as PVC and solvent production

Women's Environmental Network, 22 Highbury
Grove,London N5 2EA Tel: 071 354 8823

Measuring amounts of dioxins

We have to use very small quantities such as picograms to measure dioxins because they are so tox ic. One picogram (pg) is one millionth of a millionth of a gram. One picogram per gram (pg/g) is one part per trillion (million million) - written as ppt. 1 pg/g = 1ppt. Amounts in food and in our bodies are often measured in ppt.

Dioxin contamination is usually made up of a mixture of chemicals, and the toxicity of these different compounds varies. The amount of each type is multiplied by a number representing its toxicity (a TEF) and then all the contributions of all the different types are added up. This gives an overall toxicity in toxic equivalents or TEQs.

US assessment of dioxin toxicity

For three years, the United States Environmental Protection Agency (EPA) has been carrying out a thorough, public review of dioxin toxicity. In a draft published in May they presented their most recent conclusions:

The US EPA has previously stated that dioxins do cause cancer in humans. In the recent draft they estimate risks of cancer due to dioxins in the general population. Existing levels of dioxins in the US popu- lation may cause cancer in one in every ten thousand or even in one in every thousand people in a lifetime. In the UK, this would be behveen 6,000 and 60,000 cancers in a lifetime of 60 years, or between 86and 660 cancers a year.

Non-cancer effects include damage to reproductive, hormone and immune systems. These effects of dioxin, in animals and humans, are much worse than was previously thought. The EPA says that some of these effects are already occurring in the US popuia- tion. In the UK, we have, if anything, higher levels of dioxins in our bodies.

On average, we are likely to have body burdens of 9 ppt of dioxin TEQs. The US EPA states that monkeys get endometriosis at 27 ppt. Decreased testosterone occurs in men at 13 ppt. Altered glucose tolerance (suggesting the threat of diabetes occurs at 14 ppt in one study. Enhanced viral susceptibility is found in mice at 7 ppt, implying that we could be less resistant to viral illness at our current body level of dioxins. Dioxins stimulate the production of certain enzymes, which could have effects on cell processes, and this effect is found in rats at 1 pp. So virtually the whole human population could already be experiencing these subtle changes.


Cut down on animal fat foods like full-cream mil, cheese and meat.
Avoid eating large amou nts of fish, especially from polluted areas like the Mersey and Humber.
Don't change your. diet suddenly. This could make you lose weight, releasing stored dioxins from your fat into your blood stream.
Carry on breastfeeding: breastfed babies are healthier and may be more intelligent, despite dioxins.

What is chlorine?

Chlorine is one of the 100 or so elements that make up all living and non-living things. It has always existed on earth, but mainly in safe non-active forms such as in ordi- nary common salt. Since the early 1960s, however, there has been considerable concern about the unsafe, artificial forms of this element such as chlorine gas and organochlorine compounds.

Chlorine gas (elemental chlorine) is pro- ducedwhensalt is split upto make caustic soda, an essential industrial chemical. The processis not easy: it requires a large input of energy and is usually done by passing an electric current through brine (salt solution). Mercury, a metal which is associated with severe health and envi- ronmental effects, is often still used. Chlorine is a by-product of the manufac- ture of caustic soda for which uses, many of them disastrous, have been sought. Partof thesolutiontothe chlorine problem will be to successfully manufacture caustic soda without pro-' ducing chlorine, a process which is already beginning The German Council of Experts for Environmental Issues, a government think- tank, stated in 1990:
'.... the dynamic growth of chlorine chemistry during the 50s and 60s represents a decisive mistake in twentieth century industrial development, which would not have occurred hadour present knowledge of environmental damage and health risks due to chlorine chemistry then been available.'

The effects of organochlorines

Only a small percentage of chlorine made is used for chlorination and for making other chemicals: most is made into organochlorines. Organochlorine compounds are chemicals in which chlorine is strongly bound to carbon, the major building block for all living things.

Organochlorines are made by reacting chlorine gas with organic chemicals from the coal and oil industries. After World War II the petrochemical industry expanded and organochlorine production increased. As a result, the quantities of synthetic organochlorines now in the environment far outweigh trace amounts that might occur naturally.

Many organochlorines are strongly fat- seeking- they tend to build up in the fatty parts of living creatures where they become more concentrated and toxic.

Many chemicals that are environmentally damaging are organochlorines like PCBs and DDT. The pesticide DDT is now banned in many countries.

CFCs (chlorofluorocarbons) which damage the ozone lays contain chlori ne. The CFCs break down in the earth's upper atmosphereto release their chlorine. This chlorine destroysthe ozone layer which protects us front harmful ultraviolet rays. Many additional skin cancers and damage to vegetation will be caused as a result of this ozone depletion.

CFCsand otheroompounds such as 1,1,1 - trichloroethane, a solvent used in correcting fluid, contribute to the greenhouse effect by absorbing the sun's heat and preventing Ifrom escaping into space.

Organochlorines,such as trichloroethylene which breakdown to form acids in the air, contribute to acid rain and consequently to damage done to trees and wildlife.

PCBs are a past product of the chlorine industry. Their main use has been in equipment in electricity substations and in washing machines and electric motors. Accidents involving PCBs have caused severe poisoning andtheir manufacture - and use is now banned worldwide. A large amount of the PCBs producedin the past are still present in our environment, especially in the sea wherethey are concentrated in the bodies of fish.

Many organochlorines have been connected with effects on human health:

Perchloroethylene (perc), is an organochlorine and the main solvent used in dry cleaning. It is recognised as a probable human carcinogen in California and Sweden. An increased risk of miscarriage has been found in women exposed to perc in early pregnancy.

Pentachlorophenol (PCP) and lindane, both used for wood treatment, have caused ill health in employees and in people who have had their homes treated with either of these chemicals.

Dioxin-like compounds

Dioxins, furans and PCBswhich are generally referred to as dioxin-like compounds are highly toxic organochlorines. These compounds are extremely fat-seeking: once eaten they become stuck in bodyfat where they can remain lor many years. Although the average amounts of dioxin- like compounds in our bodies are very small (measured in parts in a million million) they are thought to be associated with damage to the nervous systems of babies before birth.

Minute traces of dioxins may have existed before industrialisation, but a huge rise occurred in the 1940s. This parallels the massive expansion of organochlorine manufacture which started at this time.

Organochlorines are rarely found in living systems; those that are have specialised and powerful functions, sometimes as natural disinfectants. There are some natural organochlorines in the atmosphere, but considerably greater amounts of artificially produced ones.

Chlorine bleached paper
In the paper-making process, wood is broken down, and many different chemical compounds are produced. If chlorine is then used to bleach the woodpulp, it reacts with these chemicals to form dioxins and hundreds of other organochlorines These are then discharged to rivers in the affluent from pulp millsorburnt as sludge in incinerators and traces also remain in the paper products themselves.

Chlorine is not used in woodpulping in Britain, but chlorine bleached pulp is imported and so supports the continuation of an extremely polluting process in other countries. Pulp does not have to be bleached with chlorine - paper products made from unbleached and non-chlorine bleached pulp are now available throughout Europe.

The US government Environmental Protection Agency is conducting a public review of dioxin toxicity. Its research shows

The UK's "tolerable daily intake" implies that these levels are safe but its basis has never been openly discussed. This contrasts with the US public review proces.


USE milk bottles, not cartons
BUY in bulk, REJECT excess packaging
USE less paper, USE recycled paper, send your waste
paper for recycling.
LOOK FOR Totally Chlorine Free (TCF) paper products.
USE reusable nappies, not disposables.

DO NOT BURN rubbish, especially plastic and painted or treated wood.

AVOID organochlorine products, PVC in cling film,
stationery and shampoo bottles, solvents in paint remover
and correcting fluid, Pentachlorophenol and Lindane in
wood preservatives. Some disinfectants contain
organochlorines - look at the label.

CHOOSE clothes that can be washed at home. AVOID
dry cleaning: perchloroethylene is hazardous in use and it
is a bulk chlorine product whose manuf acture and disposal
create long lasting toxic pollution Alternative treatments
for non-washable clothes are already being developed.

USE water based correction fluid; avoid 1,1,1-

ENCOURAGE companies to reduce waste and to cut
their use of organochlorines.

ASK companies if products contain organochlorines. Ask
supermarkets what their packaging is made from, and
avoid packaging which contains organochlorines. PVC
packaging is often labelled with a "V".

USE water based paint; solvents may include

LOOK on product labels. Organochlorine products often
have "chloro" in their names; check the label and avoid
the chlorine. Alternatives are usually available.

EAT ORGANIC FOOD; avoid or cut down on pesticides -
many are still organochlonines.

USE less petrol - leaded petrol is a small source of dioxins
and although unleaded petrol is a better option it is
becoming apparent that there are health problems linked
to this too.

USE paper wallpaper - vinyl wallpaper is PVC.
USE cork or line for floor covering.
USE less plastic generally where possible - some plastics
other than PVC involve chlorine in their production


British Plastics Federation 5 Belgrade Square, London
SW1 Tel 071-235 9483
Chemical Industries Association Kings Buildings, Smith
Square. London SW1P 355 Tel 071-834 3399
Communities Against Toxics 31 Station Road, Little
Sutton, South Wirral, L66 1NU Tel 051-339 5473
Friends of the Earth 26-28 Underwood Street, London
N1 Tel 071-490 1555
Greenpeace Greenpeace House, Canonbury Villas,
London N1 Tel 071-354 5100
Hutton & Rostron Netley House, Gomshall, Surrey GU5
9QA Tel (0483) 203221. Architects who give information
on alternatives to toxic wood treatments
London Hazards Centre Headland House, 308 Grays
Inn Road, London WC1X 8DS Tel 071-837 5605
ICI (Imperial Chemical Industries plc)9 Millbank
London SW1 Tel 071-834 4444


Chlorine, Pollution & the Parents of Tomorrow, Ann Link,
WEN Publications 1991
Dioxins in the Environment, Pollution Paper 27, HMSO
1989 £8.60
Dioxins in Food, Food Surveillance Paper 3 1 , HMSO 1992
Toxic Treatments; Wood preservative hazards at work
and.in the home, London Hazards Centre, 1988 £5.95
Living with Dioxins in North East Derbyshire WEN, 1993


You can reduce your intake of dioxin-like chemicals by cutting down on animal fat foods such as full-cream milk, cheese and meat. It may be unsafe to get all your milk and meat from one local farm if you live in a city or industrial area. Avoid eating large amounts of fish from polluted areas such as the Mersey and Humber. Processed foods often contain hidden animal fats - look at the label.

Changing your diet very suddenly could make you lose weight quickly, releasing pollutants from fat which could burden the liver and other organs.

Most people eat too much fat and protein and should eat more fruit, vegetables and starchy foods.

Breast feeding: breastfed babies are healthier and may be more intelligent. Any significant risk from pollutants in the mother is likely to be from intake before birth. However, the fact that dioxin-like pollutants occur in our food, our bodies and in unborn children means that we should reduce these pollutants at source.

The Women's Environmental Network Trust is one of Britain's leading environmental charities. It is a non-profit organisation funded by grants and donations. Its aim is to educate, inform and empowerwomen who care about the environment. WEN campaigns are funded mainy by members.

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Researched and written by Ann Link, Laura Canning and Rebecca Rees. Cartoon by Valerie Jones. Cover illustration by Daksha Patel

Updated June 1994
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