DDT is still used in developing countries for public health vector control of malaria and other tropical diseases. It is widely banned for agricultural uses. DDT caused concern because of its environmental persistence: it accumulates and concentrates in fatty tissues, and is found in human breast milk in most parts of the world. It caused reproductive failures in bird populations, because it caused thinning in egg shells which then broke prematurely, preventing the hatching of chicks.
As with many pesticides, the use of the product contributed to its downfall - the development of resistant pest populations meant that DDT was in many cases no longer effective. It was the increasing rate of resistant mosquito and other pest populations that reduced its effectiveness and which led to its withdrawal from use in agriculture, rather than environmental groups calling for a ban. The UN Environment Programme considers that resistance to DDT and other pesticides accounts for the fact that the incidence of malaria in many countries is now approaching levels of 30 years ago.
Other long-term adverse effects of DDT on human health are surfacing. The US Environmental Protection Agency and the independent UN body, the International Agency for Research on Cancer, both regard DDT as a possible human carcinogen.
Recent research from the US also links DDT with the disruption in animals and humans of endocrine functioning. It is now thought possible that some synthetic organic chemicals, including DDT, can disrupt certain natural hormones in the body by mimicking their action, leading ultimately to birth defects and reproductive cancers.
Risk assessment is a difficu1t area in which industry and environmental groups are entitled to have their say. However, nostalgia and hindsight are no substitute for consideration of the facts: the considered judgement of independent scientists and regulators is that DDT is neither green nor clean. The sooner the nuclear industry accepts this the better.
The Pesticides Trust
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