多因子影响下铜的水质基准及生态风险

为探究特定水环境中多因子影响下的铜水质基准及生态风险,采用物种权重敏感度分布法、水效应比法和生物配体模型推导保护太湖水生生物铜的水质基准.根据推导结果,推荐采用最大浓度基准值(CMC)1.43 μg/L和持续浓度基准值(CCC)1.33 μg/L.结合水效应比法和生物配体模型,采用联合概率法评估太湖铜的生态风险.结果表明,两种方法下丰水期5%水生生物受到铜慢性毒性影响的概率分别为23.43%和39.43%,而未考虑多因子影响的风险概率为85.01%,高估了太湖铜生态风险.可见,水环境多因子对水质基准和生态风险的影响不容忽视,我国目前使用的铜标准可能无法保护特定区域的水生生物.考虑多因子影响可提高基准值推导和风险评估的科学性,避免"过保护"和"欠保护"现象.

The water quality criteria and ecological risks of copper under the influence of multiple factors

In order to explore the impact of multiple factors on water quality criteria and ecological risks, the weighted species sensitivity distribution (WSSD), water effect ratio (WER) and biological ligand model (BLM) were used to derive the water quality criteria of copper for protecting aquatic organisms in Tai Lake. The criterion maximum concentration (CMC) of 1.43μg/L and the criterion continuous concentration (CCC) of 1.33μg/L were recommended as the water quality criteria of copper in Tai Lake. Joint probability curve (JPC) combining WER and BLM were used to further assess the ecological risks. There were 23.43% (WER) and 39.43% (BLM) probability of affecting 5% aquatic organisms during wet season in Tai Lake, respectively, while the traditional method overestimated the risks of copper in Tai Lake with a probability of 85.01%. These findings clearly suggest that the influence of multiple factors in the aquatic environment on water quality criteria and ecological risks cannot be ignored, currently environmental quality standard of copper adopted in China may not be able to protect aquatic organisms in specific areas such as Tai Lake. Considering multiple factors will obtain more reasonable water quality criteria and ecological risks assessment results, and avoid the phenomenon of “over-protection” or “under-protection”.