DDT Let's Put It Everywhere 1946 скачать в хорошем качестве

DDT Let's Put It Everywhere 1946

From about 1945 to 1970, large amounts of DDT were released into the air and on soil or water when it was sprayed on crops and forests to control insects. DDT was also sprayed in the environment to control mosquitoes. DDT was first synthesized in 1874, but it was not until 1939 that its insecticidal properties were discovered. Sherwin Williams began marketing DDT in a paintable form in the mid 1940's under the trade name Pestroy. Production of DDT in 1971 in the United States was estimated to be 2 million kg. This represented a sharp decline from the 82 million kg produced in 1962, and from the 56 million kg produced in 1960. At the peak of its popularity in 1962, DDT was registered for use on 334 agricultural commodities and about 85,000 tons were produced. The cumulative world production of DDT has been estimated as 2 million tons. As of January 1, 1973, all uses of DDT in the United States were canceled except emergency public health uses and a few other uses permitted on a case-by-case basis. Currently, no companies in the United States manufacture DDT. DDT is presently produced by companies in Mexico and China. Since the ban on DDT was instituted in the United States and most of the world in 1972, the environmental concentrations of DDT and its metabolites have been decreasing. The persistence of DDT and its metabolites, in combination with their high lipophilicity, have contributed to the bioaccumulation (increasing concentration of a chemical in an organism which exceeds that in its environment) and biomagnification (increasing concentration of a chemical in an organism as a function of trophic level) of DDT and its degradation products in the environment. DDT accumulate in fatty tissues, with tissue concentrations typically increasing with the trophic level of the organism. People who swallowed large amounts of DDT became excitable and had tremors and seizures. They also experienced sweating, headache, nausea, vomiting, and dizziness. These effects on the nervous system went away once exposure stopped. The same type of effects would be expected by breathing DDT particles in the air or by contact of the skin with high amounts of DDT. Animal studies show that long-term exposure to moderate amounts of DDT may affect the liver. Tests in animals also suggest that short-term exposure to DDT and metabolites in food may have a harmful effect on reproduction. In addition, we know that some breakdown products of DDT can cause harmful effects on the adrenal gland. Based on all of the evidence available, the Department of Health and Human Services has determined that DDT is reasonably anticipated to be a human carcinogen. Similarly, the International Agency for Research on Cancer (IARC) has determined that DDT is possibly carcinogenic to humans. EPA has also determined that DDT is a probable human carcinogen. For more on the toxicity of DDT, read the ATSDR DDT Toxicological Profile at http://www.atsdr.cdc.gov/substances/t... . This clip is from the 1946 promotional film, Doomsday for Pests, which is available at the Internet Archives.