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Thuốc trừ sâu Organophosphorous (OPS) và thuốc trừ sâu carbamate được xử lý ở đây trong một chương duy nhất bởi vì họ chia sẻ một chế độ phổ biến của hành động: ức chế cholinesterase. Không giống như DDT và hầu hết các thuốc trừ sâu cyclodiene, họ không có một nửa sinh học dài cuộc sống hoặc các vấn đề hiện tại của biomagnification dọc theo chuỗi thức ăn. Khi các thuốc trừ sâu organochlorine như DDT, dieldrin bắt đầu sẽ được loại bỏ trong những năm 1960, họ thường được thay thế bởi OPS hoặc carbamate, được. | CHAPTER 10 Organophosphorous and carbamate insecticides 10.1 Background Organophosphorous insecticides OPs and carbamate insecticides are dealt with here in a single chapter because they share a common mode of action cholinesterase inhibition. Unlike DDT and most of the cyclodiene insecticides they do not have long biological half-lives or present problems of biomagnification along food chains. When organochlorine insecticides such as DDT and dieldrin began to be phased out during the 1960s they were often replaced by OPs or carbamates which were seen to be more readily biodegradable and less persistent although not necessarily as effective for controlling pests parasites or vectors of disease. They replaced organochlorine insecticides as the active ingredients in crop sprays sheep dips seed dressings sprays used for vector control and various other insecticidal preparations. When organochlorine insecticides were phased out the less persistent insecticides that replaced them were thought to be more environmentally friendly . However some of the insecticides that were used as replacements also presented problems e.g. because of very high acute toxicity. The insecticides to be discussed in the present chapter illustrate well the ecotoxicological problems that can be associated with compounds that have low persistence but high neurotoxicity. Organophosphorous insecticides were first developed during the Second World War both as insecticides and as chemical warfare agents. During this time several new insecticides were synthesised by G. Schrader working in Germany prominent 2001 C. H. Walker 178 Major organic pollutants among which was parathion an insecticide that came to be widely used in agriculture after the war. In the post-war years many new OPs were introduced and used for a wide range of applications. Early insecticides had only contact action when applied to crops in the field but later ones such as dimethoate metasystox disyston and phorate had systemic .
