我国地表水中典型DBPs的暴露水平及生态风险

Occurrence and ecological risk of typical DBPs in Chinese surface water

氯消毒过程中可能生成有毒有害的副产物,会对水生态系统和环境健康产生直接和间接的次生危害.三卤甲烷(THMs)和卤乙酸(HAAs)是地表水中检出率最高的消毒副产物(DBPs),其毒性效应受到广泛关注.本文检索整理了三氯甲烷(TCM)、三溴甲烷(TBM)、二氯乙酸(DCAA)和三氯乙酸(TCAA)在我国地表水暴露浓度和对水生生物的毒性效应浓度,了解我国重点流域地表水环境中TCM、TBM、DCAA和TCAA的浓度水平,分别利用急、慢性毒性数据推导预测无效应浓度(PNEC),并使用风险商(RQ)和概率生态风险评价法(PERA)对我国重点流域水环境中TCM、TBM、DCAA和TCAA进行多层次生态风险评估.结果表明,我国地表水环境中TCM、TBM、DCAA和TCAA暴露浓度范围为n.d.~51μg/L.以致死和生长、繁殖等为测试终点的急、慢性毒性数据,构建物种敏感度分布(SSD)曲线,推导出TCM、TBM、DCAA和TCAA的PNEC值分别为0.586,0.857,0和44.880mg/L;0.006,0.064,0.956和0.012mg/L.基于急、慢性毒性数据计算出的RQ小于1.我国重点流域中TCM和TCAA对1%的水生生物造成生长、繁殖等慢性毒性影响的概率分别为78.86%和20.61%,存在潜在的生态风险.

Trihalomethanes(THMs)and haloacetic acids(HAAs),the disinfection by-products(DBPs)in surface water,have given rise to major concern in recent years.In this study,exposure and ecotoxicity data of 4 DBPs(trichloromethane,tribromomethane,dichloroacetic acid and trichloroacetic acid)were collected from literature published in China and abroad,and a multiple-level environmental risk assessment was performed.THMs and HAAs were collected from previous studies,with concentrations range from n.d.to 51μg/L.Predicted no effect concentration(PNEC)for trichloromethane(TCM),tribromomethane(TBM),dichloroacetic acid(DCAA)and trichloroacetic acid(TCAA)was based on acute and chronic toxicity data.The PNEC of TCM,TBM,DCAA and TCAA derived from acute and chronic toxicity data which based on endpoints of survival,reproduction and development,with concentrations range from 0mg/L to 44.88mg/L,0.006mg/L to 0.956mg/L,respectively.Besides,risk quotient(RQ)and probabilistic ecological risk assessments(PERA)were calculated by exposure data,and PNEC of acute and chronic toxicity data.The results showed that RQ were less than 1.TCM of probabilities of exceeding NOEC based on chronic toxicity for 1%of the species were 78.86%.And TCAA of probabilities of exceeding NOEC based on chronic toxicity for 1%of the species were 20.61%.Based on these results,the ecological risks of TCM and TCAA in Chinese surface water were low.