Đang chuẩn bị liên kết để tải về tài liệu:
Toxicological Risk Assessment of Chemicals: A Practical Guide - Chapter 7

Theo định nghĩa của OECD Để liệt kê trong Phụ lục IPCS = 1 (OECD 2003a): Tiếp xúc is''Evaluation Đánh giá của sự tiếp xúc của một hệ thống, sinh vật hoặc dân số (phụ) để đại lý năm (và các dẫn xuất của nó)''phơi đánh giá là. thứ ba bước trong quá trình đánh giá rủi ro. Các term''exposure''means phân nhóm liên lạc của con người với một chất và đã-được định nghĩa bởi US-EPA là Diễn ra tại ranh giới bên ngoài của người có thể nhìn thấy, tức là da và cơ thể vào lỗ miệng và. | 7 Exposure Assessment The aim of the exposure assessment is to determine the nature and extent of contact with chemical substances experienced or anticipated under different conditions. 7.1 INTRODUCTION According to the OECD IPCS definitions listed in Annex 1 OECD 2003a Exposure assessment is Evaluation of the exposure of an organism system or sub population to an agent and its derivatives . Exposure Assessment is the third step in the process of risk assessment. The term human exposure means contact with a substance and has been defined by US-EPA as taking place at the visible external boundary of the person i.e. skin and openings into the body such as mouth and nostrils US-EPA 1992 . An exposure assessment is the quantitative or qualitative evaluation of the amount of a substance that humans come into contact with and includes consideration of the intensity frequency and duration of contact the route of exposure e.g. dermal oral or respiratory rates chemical intake or uptake rates the resulting amount that actually crosses the boundary a dose and the amount absorbed internal dose . Depending on the purpose of an exposure assessment the numerical output may be an estimate of the intensity rate duration and frequency of contact exposure or dose the resulting amount that actually crosses the boundary . For risk assessments of chemical substances based on dose-response relationships the output usually includes an estimate of dose WHO IPCS 1999 . In most cases the substance coming into contact with the outer boundary of the body is contained in air water soil or a consumer product. The substance concentration in these media at the point of contact i.e. the exposure is the concentration on which exposure estimates are based. The most accurate exposure assessment would give information on the amount of a specific substance at the target site in the body where toxicity occurs the biologically effective doses. Figure 7.1 illustrates the relationship between exposure and .