Ecological Risk Assessment Methodology of Toxic Pollutants in Surface Water and Sediments: A Review
水体和沉积物中毒害污染物的生态风险评价方法体系

Numerous toxic pollutants enter into water and sediments due to human activities, thus causing adverse effects on aquatic organisms. Hence, conducting ecological risk assessment of contaminants and screening high-risk contaminants are the basis of risk management of contaminants and ecosystem protection. In this paper, we reviewed the methodologies of ecological risk assessment for toxic pollutants in aquatic environment used in the United States, European Union and other developed countries. Basic methodology of risk assessment for contaminants in surface water and sediments includes the following three processes: (a) Exposure assessment, which is carried out using predicted or measured environmental concentrations (PECs or MECs); (b) Impact assessment, which is performed using predicted no effect concentrations (PNECs) derived from aquatic toxicity data through dose-effect relationship; (c) Risk characterization, which is ranked by risk quotient (RQ) from the ratio of PEC (or MEC) to PNEC. However, for the pollutants lacking toxicity data in sediments, the risk assessment of the organic pollutants can be carried out using the aquatic risk assessment method after obtaining the concentration of the pollutants in pore water, which is calculated from the concentration in sediments according to the organic carbon-normalized sediment/water partition coefficient of the organic pollutant. And for the metal pollutants in sediments, the risk assessments can be characterized by risk assessment code (RAC) or by the subtraction method of acid volatile sulfide (AVS) and simultaneously extracted metals (SEM). Based on the review, we proposed a risk assessment methodology for toxic pollutants in surface water and sediments in China, aiming to provide information for contamination risk management of China.