风险污染物短期高剂量暴露下的生态风险评估方法

Method of Ecological Risk Assessment for Risk Pollutants Under Short-term and High Dose Exposure in Water Pollution Accident

水污染事故的短期高剂量暴露造成的急性生态危害及水生生物安全问题成为人们研究的重点,但我国以往的水污染事故,多采用地表水环境质量标准和生活饮用水卫生标准来判断水体是否安全,缺乏对水生生物保护的安全效应阈值或风险值.国外在水生生物保护方面,虽然限定了一些风险污染物对水生生物的安全效应阈值或称为无效应阈值或风险值,但其无效应阈值的计算是基于长期暴露下的慢性毒性值,其生态风险值也是基于长期暴露下的风险,缺少对水污染事件短期高剂量暴露下化学品的阈值限定及风险评估.本研究结合常规生态风险评价的理念及美国EPA短期暴露情况下保护水生生物基准值的制定方法,探讨了水污染事件的短期高剂量暴露情况下风险污染物的生态风险评价及生态效应阈值的计算方法,并进行了实例应用,同时对建立我国水污染事故生态风险评估方法体系提出了建议.

In recent years,water pollution accidents resulting in acute aquatic ecological risk and security issues become a research focus.However,in our country,the surface water quality standards and drinking water health standards were used to determine the safety of waters or not in pollution incidents due to lacking safety effect threshold or risk value for protection of aquatic life.In foreign countries,although predicted no effect concentration（PNEC） or risk value（R） of pollutants were provided for protection of aquatic organisms,the PNECs or risk values were derived based on long-term exposure toxicity data NOECs（no observed effect concentrations） and lack of short-term exposure risk or threshold values.For the short-term and high dose exposure in pollution incident,ecological risk assessment methods were discussed according to the procedures of the conventional ecological risk assessment and the water quality criteria establishment of the U.S.EPA for the protection of aquatic organisms in short-term exposure,and had a case study.At the same time,we provide some suggestions for the establishment of ecological risk assessment system in water pollution incidents.