05-22-2008, 02:09 AM
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Machiavelli Incarnate
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Join Date: Jun 2006
Location: Mid-south
Posts: 11,395
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What DDT actually does...
Quote:
DDT Breakdown products in the soil environment are DDE (1,1-dichloro-2,2-bis(p-dichlorodiphenyl)ethylene) and DDD (1,1-dichloro-2,2-bis(p-chlorophenyl)ethane), which are also highly persistent and have similar chemical and physical properties. These products together are known as "total DDT".
DDT is a toxicant across a certain range of phyla. In particular, DDT is a major reason for the decline of the bald eagle in the 1950s and 1960s as well as the brown pelican and the peregrine falcon. DDT and its breakdown products are toxic to embryos and can disrupt calcium absorption, thereby impairing eggshell quality. Studies in the 1960s and 1970s failed to find a mechanism for the hypothesized thinning. However, more recent studies in the 1990s and 2000s have laid the blame at the feet of DDE. Some studies have shown that although DDE levels have fallen dramatically, eggshell thickness remains 10–12 percent thinner than before DDT was first used. DDT is also highly toxic to aquatic life, including crayfish, daphnids, sea shrimp and many species of fish. DDT may be moderately toxic to some amphibian species, especially in the larval stages. In addition to acute toxic effects, DDT may bioaccumulate significantly in fish and other aquatic species, leading to long-term exposure to high concentrations.
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