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DDT

2013-11-13 来源: 类别: 更多范文

DDT DDT and The Environment: The Effects on the Ecosystem As earth's population grows so does the demand for food, and the use of pesticides has become essential in meeting this demand. The first important synthetic organic pesticide was a chlorinated hydrocarbon, dichlorodiphenyltrichloroethane or DDT. DDT was discovered in 1939 by Swiss chemist Paul Müeller. In its early days, DDT was a popular pesticide because it was toxic to a wide range of insect pests, yet it appeared to have low toxicity to mammals. DDT was also persistent, which meant the pesticide didn't break down rapidly in the environment and therefore did not need to be reapplied often and since DDT was insoluble it did not wash off by rain or other weather conditions. Although gradually throughout time it was discovered that many insects had developed resistance to DDT, and it was discovered that DDT did in fact pose to be harmful to the ecosystem. This discovery created wide public interest and made people aware that chemicals were polluting the environment. As a resu! lt DDT was banned for use in North America and other countries in the early 1970’s. Though pesticides, such as DDT, may decrease the number of insects, throughout history ddt, environment, pesticide, food, chemical, soil, pesticides, birds, water, insects, effects, chain, body, animals, higher, effect, discovered, chemicals, because, wildlife, very, time, therefore, plants, negative, humans, exposure, amounts, although, able, within, toxicity, top, thus, through, society, populations, persistent, often, levels, however, first, developed, break, toxic, stored, species, since, result, quantities
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