Toxic, or poisonous wastes are produced during industrial, chemical, and biological processes. Even household, office and commercial wastes contain small quantities of toxic wastes (e.g. batteries, old pesticides and their containers).

Dioxins: Produced by burning chlorine-containing substances e.g. plastics; the manufacture of iron and steel, and some organic chemicals e.g.herbicides. Found in bleached white paper.

Heavy metals: Widespread industrial use, such as in cadmium and nickle plating. Found in batteries (mercury, cadmium, lead) and leaded petrol.

Radioactive waste: By-product of nuclear power generation and used in medicine (e.g. cancer therapy).

Land disposal: Waste is buried in landfills which should be permanently sealed to contain the waste. Landfills may be lined with clay or plastic, or waste may be encapsulated in concrete. However, there is no guarantee that a leak will not occur.

Incineration (burning): May be low temperature (urban refuse) or high temperature incineration. The latter is best for many industrial wastes (tar, paint, pesticides, solvents) as it prevents formation of dioxins. High temperature incineration is not yet available in South Africa.

Chemical or biological: Chemicals are added to waste, and they make it less toxic; or bacteria "eat" the waste, resulting in a less toxic residue.

Transporting (often by sea) waste to another country runs the frightening risk of spillages. The receiving country often lacks the expertise and technology to deal with the toxic waste in the safest way - local people are then at risk. International concern about the export of toxic waste is reflected in the Lom‚, Basel and O.A.U. (Organisation of African Unity) Conventions.

Each country should take responsibility for its own toxic waste. Shipping waste to other countries is no solution, it merely moves the problem.

* substitution of non-polluting alternatives, e.g. chlorine, used to bleach wood, results in the formation of dioxins - chlorine could be replaced with oxygen; * efficient production processes and good maintenance of machinery can reduce waste production;

* recycling of waste reduces pollution and can result in cost- saving e.g. expensive, toxic heavy metals could be re-used.

* Avoid waste creation in your own home: reuse, reduce, recycle (see Enviro Facts "War on Waste").

* Avoid using toxic products at home (see Enviro Facts "Poisons in the Home and Garden").

* Dispose of household toxic substances into plastic bags in municipal bins. Never flush poisons down the toilet, or pour them into drains at home, stormwater drains, or rivers and dams.

* Become informed, join forces with concerned people and make your voice heard - see contacts below.

NB: Reduce it - don't produce it! What cannot be recycled, or is too dangerous to handle, should not be used or produced in the first place.

* The Institute of Waste Management is researching the possibility of carrying out environmental audits of toxic waste dumps. An environmental audit is an analysis of any human activity to assess its environmental consequences.

WATER, WASTE AND WILDLIFE. E. Koch, D. Cooper and H. Coetzee. Penguin, 1990.

WORK FROM WASTE. J. Vogler. ITT, London, 1983.

WASTE NOT, WANT NOT - THE PRODUCTION AND DUMPING OF TOXIC WASTE. R. Allen, Earthscan/WWF, London, 1992.

CSIR: Environmental Services. P O Box 395, Pretoria 0001. Tel. 012-8414730.

Department of Water Affairs & Forestry. P. Bag X313, Pretoria 0001. Tel. 012-299 9111.