clo hydrocarbon Lớp cái nhìn tổng quan và bối cảnh mô tả chung Hydrocarbon clo, còn được gọi là organochlorines, được sử dụng rộng rãi từ những năm 1940 đến những năm 1960 để kiểm soát dịch hại nông nghiệp và cho các chương trình kiểm soát bệnh sốt rét. Từ những năm 1960 sử dụng ở Mỹ đã được rút ngắn rất nhiều vì sự kiên trì của họ trong môi trường, động vật hoang dã và con người. Thuốc bảo vệ thực vật chịu trách nhiệm về mức giảm này là dichlorodiphenyltrichloroethane (DDT). Sử dụng DDT đã bị loại. | chapter six Chlorinated hydrocarbons Class overview and general description Background Chlorinated hydrocarbons also known as organochlorines were used widely from the 1940s to the 1960s for agricultural pest control and for malarial control programs. Since the 1960s their use in the . has been curtailed greatly because of their persistence in the environment in wildlife and in humans. The pesticide most responsible for this reduction was dichlorodiphenyltrichloroethane DDT . DDT use has been eliminated in the . though it is still applied in many regions throughout the world. The organochlorines can be divided into three groups 1 dichlorodiphenylethanes DDT and related compounds Figure 2 cyclodiene compounds Figure and 3 other related compounds. In addition particular organochlo-rines may consist of a number of related compounds. For example toxaphene is made up of more than 177 related compounds. Although there is no structure common to all organochlorines they are all characterized by one or more chlorine atoms positioned around one or more hydrocarbon rings. Members of each group of organochlorines share similar or identical compositions although they may have very different three-dimensional structures and shapes. These isomers may differ significantly in their toxicities and other characteristics. The generic structures of dichlorophenyl ethanes and cyclodienes are shown in Figures and respectively. The latter is a member of the cyclodiene group. Dichlorophenylethanes cyclodienes and other chlorinated hydrocarbons are listed in Table . Chlorinated hydrocarbon usage Organochlorines are powerful pesticides and members of this group can be produced at relatively low cost. At one time DDT sold to the World Health Organization WHO cost less than per pound. DDT use reached a peak in 1961 when 160 million pounds were manufactured 80 of that volume was used for agriculture. The other organochlorines also saw a great upsurge in use
