考虑物种权重校验保护太湖水生生物的铅基准

Weighted species sensitivity distribution method to derive site-specific quality criteria of lead for protection of aquatic life in Tai Lake

铅是一种有毒重金属元素,位列我国水中优先控制污染物"黑名单".我国水系众多,水生生物多样,研究保护区域水生生物的铅基准十分必要.太湖作为中国周边经济最发达、大中城市最密集且污染最严重的淡水湖泊之一,本研究选取8种太湖本土水生生物实验补充铅的急性毒性数据并两步外推得到慢性毒性数据.结合文献建立铅的本土毒性数据库,基于水体硬度对铅毒性的影响,建立硬度和毒性关系.考虑太湖生物区系和水质特征,采用物种权重敏感度分布方法,得到保护太湖水生生物铅的最大浓度基准值(CMC)和持续浓度基准值(CCC)值分别为50.04—58.87μg·L-1和3.99—4.69μg·L-1;现行地表水铅的Ⅲ类标准限值(50μg·L-1)下受铅急性毒性和慢性毒性影响的生物比例分别为4.42%和23.00%.

Lead is a toxic heavy metal and has been included in the "black list" of priority pollutants in water in China. It is necessary to establish a regional water quality benchmark for lead which aims at protecting resident aquatic life because of the numerous water systems and the diversity of aquatic organisms in China. Tai Lake is one of the most developed economies, most densely populated area and most polluted freshwater lakes in China. Eight native aquatic species were selected to construct acute toxicity tests to supplement the acute toxicity data of lead and further extrapolate chronic toxicity data. The toxicity database of lead of aquatic organisms in Tai Lake was established based on literature and then a relationship between water hardness and toxicity was constructed because hardness affects the biotoxicity of lead. The derived criterion maximum concentration(CMC) and criterion continuous concentration(CCC) for lead in Tai Lake were 50.04—58.87 μg·L-1 and 3.99—4.69 μg·L-1, respectively, using the weighted species sensitivity distribution method in consideration of taxonomic groups and water characteristics in Tai Lake. Besides, the proportion of organisms affected by the acute and chronic toxicity of lead derived from weighted species sensitivity distribution was 4.42% and 23.00% under the class III standard limit(50.00 μg·L-1) of lead.