Biocides are used to kill living things, e.g. rats and mice (rodenticides), insects (insecticides), weeds (herbicides), bacteria (disinfectants) or fungi (fungicides). Concern over biocides grows as people realise that many of their ingredients can cause allergies, initiate cancer, promote genetic mutations and birth defects.

Much effort goes into making sure that biocides are relatively safe. However, they are designed to kill, and just as they are effective against ants, flies and mice, so they can harm people and their pets as well as birds, butterflies, bees and spiders. In addition to the dangers of toxicity, some substances accumulate or build up in the body as we get repeated doses.

INSECTICIDES

The most commonly used poisons in the home are insecticides. They are mostly nerve poisons and may cause cumulative damage to the nervous system and liver, as well as be a cancer risk. They are probably the most poisonous substances that we use in our homes. Some common active ingredients include:

- Organochlorines: originally considered very useful because of their relatively low acute toxicity. Some, for example DDT take a long time to break down into harmless substances, and can accumulate in the bodies of animals and hence in food chains. The use of most persistent varieties has been banned in the First World.

- Organophosphates: although more acutely dangerous and poisonous than organochlorines, these compounds are thought to break down more quickly. Most human poisonings are caused by organophosphates. Malathion is a common ingredient in garden insecticides.

- Carbamates: these were developed as pests became resistant to the previous two poison types. Carbaryl is found in many home insecticides.

- Pyrethroids: these synthetic insecticides are based on the natural pyrethrum found in some chrysanthemums. Pyrethroids break down quickest in the environment and are thus safer. They are, nevertheless, toxic and must be handled carefully.

WHAT YOU CAN DO ABOUT PESTICIDES

* Ask yourself whether those ants, snails and mice really need to be killed?

* Read the small print and follow instructions carefully.

* Remove pests by hand where possible.

* Keep pesticides away from pets and children.

* Keep pesticides in their original containers which should be clearly marked and tightly sealed. Keeping a weed killer, for example, in a cool drink bottle can be a recipe for disaster.

* When using an aerosol pesticide, cover your hand with a glove or plastic bag to avoid skin contact with poison.

* If you must use rat poison or snail bait, cover it so that birds can't get to it, and remove it as soon as possible. * Do not mix pesticides, or use more than one at a time. * Look for alternatives, such as products containing pyrethrum and rotenone (see Gaia Research Institute below).

* Become informed - the more you know, the safer your home and environment will be.

OTHER HOUSEHOLD POISONS

Oven cleaners contain caustic soda, detergents contain phosphates, moth balls contain naphthalene, disinfectants contain phenols and many household cleaners are ammonia-based or bleach- based! The active ingredients of these familiar products can be toxic, irritants, allergy causing - or all three.

WHAT YOU CAN DO ABOUT HOUSEHOLD PRODUCTS

* Use sparingly, and experiment with safer alternatives:
Baking soda: cleans ovens, deodorises, softens water, good scourer for greasy surfaces and plates
Borax: cleans, deodorises, disinfects, softens water, repels cockroaches
Baby powder and ground cloves: repel ants Washing soda: cuts grease, removes stains, disinfects, washes clothes, cleans oven
White vinegar: cuts grease, freshens, cleans toilets and windows
Hot water: cleans lightly soiled dishes
Incense, essential oils (extracted from herbs) and fresh or dried herbs: excellent toilet fresheners, and keep fishmoths out of cupboards.

REMEMBER

* Never, never pour pesticides or household chemicals down the drain, into the toilet or stormwater drains, rivers, or dams. As there are no facilities for the disposal of toxic or hazardous waste in South Africa, the best option is to dispose of them into your municipal rubbish bin. However, once on the municipal rubbish dump, hazardous waste can still contaminate the environment. Encourage your local municipality to establish a facility for the disposal of hazardous waste.

* Even safer alternatives may be poisonous and should be handled with care. Borax, for example, will cause vomiting if swallowed in small quantities and should be kept out of reach of children.

* For advice on cases of human poisoning contact the Poison Information Centre: Johannesburg 011-642 2417, Bloemfontein 051-475 353, Cape Town 021-689 5227.

* For advice on cases of animal poisoning contact the Animal Rehabilitation Centre 012-808 1106.

FURTHER READING

THE GREEN CONSUMER GUIDE. J. Elkington and J. Hales. Gollancz, London, 1988.

YOUR GUIDE TO GREEN LIVING IN SOUTHERN AFRICA. W. McLintock. Enviromac, Johannesburg, 1990.

50 SIMPLE THINGS KIDS CAN DO TO SAVE THE PLANET. The Earth Works Group. Sphere, 1990.

THE SOUTH AFRICAN FIRST AID MANUAL. St. Johns Ambulance and South African Red Cross Society. Struik, Cape Town, 1990.

HOUSEHOLD HAZARDS. An informative pamphlet available from Earthlife Africa, Grahamstown. P.O. Box 2260, Grahamstown, 6140.

Enviro Facts: Farmers, Poisons and Wildlife.

USEFUL ADDRESSES

Gaia Research Institute. Stuart Thomson, P O Box 71, Wittedrif. Tel. 04457-9716

Earthlife Africa. All numbers office hours. Cape Town 021-761 0928, Durban 031-942565, Johannesburg 011-839 3764, Pretoria 012-344 1916, Grahamstown 0461-23778

Poison Working Group. PO Box 15121, Lynn East, 0039. Tel. 012-808 0592.