Các thuốc trừ sâu organochlorine có thể được chia thành ba nhóm chính, mỗi trong số đó sẽ được thảo luận một cách riêng biệt trong các phần tiếp theo. Đây là những hợp chất DDT liên quan, thuốc trừ sâu cyclodiene và đồng phân của HCH (Brooks, 1974; Hình ). Các thuốc trừ sâu organochlorine đầu tiên để trở thành sử dụng rộng rãi là DDT. Mặc dù lần đầu tiên được tổng hợp bởi Zeidler vào năm 1874, tài sản côn trùng của nó không được phát hiện đến năm 1939 bởi Paul Mueller của Thụy Sĩ công. | PART 2 Major organic pollutants 2001 C. H. Walker CHAPTER 5 The organochlorine insecticides Background The organochlorine insecticides can be divided into three main groups each of which will be discussed separately in the sections that follow. These are DDT and related compounds the cyclodiene insecticides and isomers of HCH Brooks 1974 Figure . The first organochlorine insecticide to become widely used was DDT. Although first synthesised by Zeidler in 1874 its insecticidal properties were not discovered until 1939 by Paul Mueller of the Swiss company J. R. Geigy. DDT production commenced in the Second World War during the course of which it was mainly used for the control of insects that are vectors of disease including malarial mosquitoes and the ectoparasites that transmit typhus . lice and fleas . DDT was used to control malaria and typhus both in the military personnel and in the civilian population. After the war it came to be used widely to control agricultural and forest pests. After the introduction of DDT the related compounds rhothane DDD and methoxychlor were also marketed as insecticides but they were only used to a very limited extent. Restrictions began to be placed on the use of DDT from the late 1960s on with the discovery of its persistence in the environment and with growing evidence of its ability to cause harmful side-effects. HCH sometimes misleadingly termed benzene hexachloride BHC exists in a number of different isomeric forms of which the Y-isomer has valuable insecticidal 2001 C. H. Walker 92 Major organic pollutants properties. The insecticidal properties of HCH were discovered during the 1940s and it came to be widely used as an insecticide to control crop pests and certain ectoparasites of farm animals after the Second World War. Crude technical BHC a mixture of isomers was the first form of HCH to be marketed. In the course of time it was largely replaced by a refined product called lindane containing 99 or more of the .

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