Chương này sẽ xem xét các quá trình xác định độc tính của các chất ô nhiễm hữu cơ để các sinh vật sống. Thuật ngữ "độc tính" sẽ bao gồm các ảnh hưởng có hại nói chung và sẽ không bị hạn chế để gây chết. Với những tiến bộ nhanh chóng trong cơ chế độc tố trong những năm gần đây, càng ngày càng có thể hiểu được trình tự cơ bản của những thay đổi dẫn đến sự xuất hiện của triệu chứng nhiễm độc và làm thế nào sự khác biệt trong hoạt động của các. | CHAPTER 2 Factors determining the toxicity of organic pollutants to animals and plants Introduction This chapter will consider the processes that determine the toxicity of organic pollutants to living organisms. The term toxicity will encompass harmful effects in general and will not be restricted to lethality. With the rapid advances in mechanistic toxicology in recent years it is increasingly possible to understand the underlying sequence of changes that leads to the appearance of symptoms of intoxication and how differences in the operation of these processes between species strains sexes and age groups can account for selective toxicity. Thus in a text of this kind it is convenient to deal with these principles at an early stage because they underlie many of the issues to be discussed later. It is important to understand why chemicals are toxic and why they are selective not only as a matter of scientific interest but also for more practical reasons. An understanding of mechanism can contribute to the development of new biomarker assays the design of more environmentally friendly pesticides and the control of resistant pests. 2001 C. H. Walker Factors determining toxicity 15 Although many of the standard ecotoxicity tests use lethality as the end point it is now widely recognised that sublethal effects may be at least as important as lethal ones in ecotoxicology. Pollutants that affect reproductive success can cause populations to decline. The persistent DDT metabolite p p -DDE p p -dichlorodiphenyldichloroethylene caused the decline of certain predatory birds in North America through eggshell thinning and consequent reduction in breeding success see Chapter 5 . The antifouling agent tributyltin TBT caused population decline in the dog whelk Nucella lapillus through making the females infertile see Chapter 8 . Neurotoxic compounds can have behavioural effects in the field see Chapters 5 and 10 and these may reduce the breeding or feeding success of animals.
