tailieunhanh - ORGANIC POLLUTANTS: An Ecotoxicological Perspective - Chapter 4

Trong Chương 3, phân phối hóa chất môi trường thông qua các ngăn của môi trường tổng liên quan đến các yếu tố hóa học và quá trình tham gia, và các mô hình để mô tả hoặc dự đoán số phận môi trường được coi là. Trong phần đầu của chương này, thảo luận di chuyển vào các câu hỏi phức tạp hơn của phong trào và phân phối trong môi trường trong đời sống cá nhân, cộng đồng, và các hệ sinh thái, sinh học cũng như các yếu tố vật lý và hóa học đi vào chơi | 4 Distribution and Effects of Chemicals in Communities and Ecosystems INTRODUCTION In Chapter 3 the distribution of environmental chemicals through compartments of the gross environment was related to the chemical factors and processes involved and models for describing or predicting environmental fate were considered. In the early sections of the present chapter the discussion moves on to the more complex question of movement and distribution in the living environment within individuals communities and ecosystems where biological as well as physical and chemical factors come into play. The movement of chemicals along food chains and the fate of chemicals in the complex communities of sediments and soils are basic issues here. Ecotoxicology deals with the study of the harmful effects of chemicals in ecosystems. This includes harmful effects upon individuals although the ultimate concern is about how these are translated into changes at the levels of population community and ecosystem. Thus in the concluding sections of the chapter emphasis will move from the distribution and environmental concentrations of pollutants to consequent effects at the levels of the individual population community and ecosystem. The relationship between environmental exposure dose and harmful effect response is fundamentally important here and full consideration will be given to the concept of biomarkers which is based on this relationship and which can provide the means of relating environmental levels of chemicals to consequent effects upon individuals populations communities and ecosystems. MOVEMENT OF POLLUTANTS ALONG FOOD CHAINS The pollutants of particular interest here are persistent organic chemicals com-pounds that have sufficiently long half-lives in living organisms for them to pass along food chains and to undergo biomagnification at higher trophic levels see Box . Some compounds of lesser persistence such as polycyclic aromatic hydrocarbons PAHs Chapter 9 can be .