Planet Watch

No matter where you live or when you were born, you almost surely have at least a small amount of DDT stored in the fatty tissues of your body. This notoriously toxic pesticide, which almost led to the extinction of the American bald eagle in the 1970s, has long been banned in the U.S. and most other developed countries. But according to a new report by the World Wildlife Fund in Washington, DDT is still used in many developing nations, mainly because it's so effective in controlling mosquitoes that carry the malaria parasite.The persistence of DDT is a problem--and not just in the countries that use it. DDT and several other common chlorine-containing pesticides are sturdy molecules that can stay intact for decades. They evaporate into the atmosphere and are blown by the wind all over the globe. They condense and fall to the ground in cold weather, especially in higher latitudes. Some of the highest concentrations of DDT are found in polar bears, penguins and the Inuit people of northern Canada.Although levels of DDT contamination are gradually falling in countries where the pesticide has been banned, new scientific research suggests that the chemicals are still a serious threat everywhere. Studies show that even small amounts of pesticide can disrupt the working of human hormones, interfering with reproduction and the functioning of the immune system. That's why representatives of more than 100 nations will gather at a U.N. meeting in Nairobi this week to work toward a global treaty that would phase out DDT and 11 other pesticides, known as the dirty dozen. Environmentalists say it's possible to find alternative ways to fight malaria--and get rid of DDT once and for all.Pesticides/usesAldrin: On crops, to control termitesChlordane: On crops, lawns and gardensDDT: On crops, to control malariaDieldrin: On crops, to control termitesEndrin: On cotton & grains, to control miceHeptachlor: On crops, to control malariaMirex: Combat fire ants & termites, as fire retardant in plasticsToxaphene: On crops, to control ticksIndustrial chemicals/usesPCBs: In electrical transformers, paint additives & plasticsHCB: In fireworks & synthetic rubber; also a pesticideUnintended by-products/sourcesDioxins: Chemical production, waste incineration, car emissions, metal smeltingFurans: Formed along with dioxins (but less potent)THE IMPACT: Effects possibly linked to DDT and other pesticides: Increased cancer, skeletal disorders and infections among the beluga whales in Canada's St. Lawrence River Disappearance of otters in certain regions of Europe Stunted reproductive organs in alligators in Florida's Lake Apopka Increased incidence of chronic infections among Inuit children in Canada Learning and attention problems in children whose mothers had eaten contaminated fish in North America's Lake Michigan Decreased physical stamina and diminished memory in exposed Mexican children