"Prioritizing Aquatic Chemical Pollutants in Terms of Potential Ecological Risk" 

Ken-ichi Miyamoto, Mari Kotake, Junko Nakanishi

National Institute of Advanced Industrial Science and Technology

Society for Risk Analysis, Annual Meeting  (New Orleans, USA 2002/12/11)

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Abstract

Evaluating the ecological risks as well as the human health risks posed by chemicals is one of the major concerns in many countries. Since a large number of chemicals are in use, several ranking and scoring systems have been developed in the last decade to screen the chemicals and to set priorities. 

Most of these systems are based on potential exposures predicted from the physical/chemical properties of substances. In these systems, the availability and quality of required data and the assumptions used to estimate emissions to the environment are critical. The purpose of this study is to set risk-based priorities for chemical pollutants for which in-depth aquatic ecological risk assessments are needed. This prioritizing system emphasizes measured concentrations of chemicals rather than predicted ones. 

More than 800 chemicals whose aquatic concentrations have been determined were evaluated. Exposure assessment dealt with uncertainties due to the limited number of surveyed data that consisted of a variety of temporal and spatial points, and to the detection limit of the measurement. In an effects assessment, the toxicity of major aquatic organisms including zooplankton, fish, and plants was surveyed from database and/or predicted using QSAR. 

Risk was characterized by a simple quotient method; however, priorities were set based upon various criteria including the magnitude of potential risks, the number of high-risk areas, the degree of uncertainty considered in both exposure and effects assessments, and the designated use of the area of potential concern. About 30 chemicals were recommended for definitive ecological risk assessment using more sophisticated techniques such as probabilistic approach.

Keywords

生態リスク評価, スクリーニング評価