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Introduction to ENVIRONMENTAL TOXICOLOGY Impacts of Chemicals Upon Ecological Systems - CHAPTER 2

Khung chất độc môi trường Độc chất trong môi trường có thể được đơn giản hóa sự hiểu biết chỉ có ba chức năng. Các chức năng này được trình bày trong hình 2.1. Đầu tiên, có sự tương tác của các chất hóa học được giới thiệu, xenobiotic, với môi trường. Sự tương tác này kiểm soát lượng độc tố hoặc liều có sẵn để sinh vật. Thứ hai, xenobiotic các tương tác với trang web hoạt động của nó. Các trang web của hành động là một loại protein đặc biệt hay phân tử sinh học khác tương tác. | CHAPTER 2 A Framework for Environmental Toxicology Environmental toxicology can be simplified to the understanding of only three functions. These functions are presented in Figure 2.1. First there is the interaction of the introduced chemical xenobiotic with the environment. This interaction controls the amount of toxicant or the dose available to the biota. Second the xenobiotic interacts with its site of action. The site of action is the particular protein or other biological molecule that interacts with the toxicant. Third the interaction of the xenobiotic with a site of action at the molecular level produces effects at higher levels of biological organization. If environmental toxicologists could write appropriate functions that would describe the transfer of an effect from its interaction with a specific receptor molecule to the effects seen at the community level it would be possible to predict accurately the effects of pollutants in the environment. We are far from a suitable understanding of these functions. The remainder of the chapter introduces the critical factors for each of these functions. Unfortunately we do not clearly understand how the impacts seen at the population and community levels are propagated from molecular interactions. THE CLASSICAL VIEWPOINT FOR CLASSIFYING TOXICOLOGICAL EFFECTS Techniques have been derived to evaluate effects at each step from the introduction of a xenobiotic to the biosphere to the final series of effects. These techniques are not uniform for each class of toxicant and mixtures are even more difficult to evaluate. Given this background however it is possible to outline the levels of biological interaction with a xenobiotic Chemical Physical-Chemical Characteristics Bioaccumulation Biotransformation Biodegradation Site of Action 1999 by CRC Press LLC Biochemical Monitoring Physiological and Behavioral Population Parameters Community Parameters Ecosystem Effects Each level of organization can be observed and examined