tailieunhanh - Species Sensitivity Distributions in Ecotoxicology - Section 2

Nguyên tắc khoa học và đặc điểm của ổ cứng thể rắn SSD Phần này giao dịch với các vấn đề lý thuyết và kỹ thuật trong nguồn gốc của phân phối loài nhạy cảm (SSD). Các vấn đề bao gồm các giả định cơ bản sử dụng của ổ SSD, việc lựa chọn và điều trị các tập hợp dữ liệu, phương pháp bắt nguồn phân phối và ước tính không chắc chắn liên quan, và mối quan hệ của các ổ SSD để phân phối tiếp xúc. Một nguyên tắc thống nhất thống kê được trình bày, liên kết. | Section II Scientific Principles and Characteristics of SSDs This section deals with theoretical and technical issues in the derivation of species sensitivity distributions SSDs . The issues include the assumptions underlying the use of SSDs the selection and treatment of data sets methods of deriving distributions and estimating associated uncertainties and the relationship of SSDs to distributions of exposure. A unifying statistical principle is presented linking all current definitions of risk that have been proposed in the framework of SSDs. Further methods for using SSDs for data-poor substances are proposed based on effect patterns related to the toxic mode of action of compounds. Finally the issue of SSD validation is addressed in this section. These issues are the basis for the use of SSDs in setting environmental criteria and assessing ecological risks Sections IIIA and B . 2002 by CRC Press LLC Theory of Ecological Risk Assessment Based on Species Sensitivity Distributions Nico M. van Straalen CONTENTS Introduction Derivation of Ecological Risk Probability Generating Mechanisms Species Sensitivity Distributions in Scenario Analysis Conclusions Acknowledgments Abstract The risk assessment approach to environmental protection can be considered as a quantitative framework in which undesired consequences of potentially toxic chemicals in the environment are identified and their occurrence is expressed as a relative frequency or a probability. Risk assessment using species sensitivity distributions SSDs focuses on one possible undesired event the exposure of an arbitrarily chosen species to an environmental concentration greater than its no-effect level. There are two directions in which the problem can be addressed the forward approach considers the concentration as given and aims to estimate the risk the inverse approach considers the risk as given and aims to estimate the concentration. If both the environmental concentration PEC and the