tailieunhanh - Organic Chemicals : An Environmental Perspective - Chapter 7

Các đầu vào cơ bản cần thiết để đánh giá độc tính của xenobiotics được tóm tắt và bao gồm các dữ liệu trên cả hai tiếp xúc với độc tố và đánh giá hiệu lực sinh học của nó về điểm kết thúc xác định số lượng. Một cuộc thảo luận ngắn gọn là sự lựa chọn của các loài thử nghiệm, phạm vi của các điểm cuối cùng chấp nhận được, và sự lựa chọn của các phương tiện truyền thông cho các xét nghiệm trong phòng thí nghiệm. Một số ý kiến được cung cấp trên xét. | Neilson Alasdair H. Ecotoxicology Organic Chemicals An Environmental Perspective Boca Raton CRC Press LLC 2000 7 Ecotoxicology SYNOPSIS The basic input required for assessing the toxicity of xenobiot-ics is summarized and includes data both on the exposure to the toxicant and an evaluation of its biological effect in terms of numerically determined end points. A brief discussion is directed to the choice of test species to the range of acceptable end points and to the choice of media for laboratory tests. Some comments are provided on the commonly used tests using single organisms that include representatives of algae crustaceans and fish with emphasis on assays for sublethal effects. Brief descriptions are given of less widely used assays using rotifers mayflies tadpoles and sea urchins. Assays for evaluating toxicity in sediments and toward terrestrial organisms are discussed and procedures for detecting genotoxic and estrogenic effects are noted. A discussion is presented on multicomponent test systems including different types of mesocosms. Attention is directed to the important question of metabolism by the test organisms with emphasis on fish. The use of biomarkers is briefly discussed and includes application of both biochemical and physiological parameters. Some cautionary comments are given on the application of these to feral fish. Attention is briefly drawn to the application of toxicity-equivalent factors and the role of epidemiology. It is suggested that a hierarchical approach to evaluating toxicity could be used and that assays at the higher levels are justified if no effects are observed at the lower ones. Any system should be flexible and should be able to incorporate studies of partition and additional factors relevant to a particular environment. Introduction Previous chapters have been devoted to the distribution and persistence of xenobiotics after discharge into the aquatic environment. This chapter is .