甲氧氯(methoxychlor,MXC)作为一种有机氯杀虫剂,由于在农业生产中的广泛应用,使其在水环境和沉积物中的检出频率均较高,并且对各种水生物种均具有毒性作用.因此,制定中国MXC水质基准(water quality criteria,WQC)和沉积物质量基准(sediment quality criteria,SQC),并开展生态风险评估,对保护中国水生生物至关重要.基于收集和筛选的17 种水生生物的急性毒性数据和 10 种水生生物的慢性毒性数据.选取物种敏感性分布(species sensitivity distribu-tion,SSD)模型的最佳拟合对WQC进行推导,MXC对水生生物的短期水质基准(SWQC)和长期水质基准(LWQC)分别为0.75 和0.11 μg/L.通过相平衡分配法,在WQC的基础上进一步推导出SQC,沉积物质量基准高值(SQC-H)和沉积物质量基准低值(SQC-L)分别为 0.73 和0.11 mg/kg.此外,通过收集中国地表水和沉积物中的MXC暴露浓度数据,利用风险商值法(risk quotients,RQ)进行生态风险评价,结果表明我国部分区域的地表水和沉积物存在一定的生态风险.本文的结果将为中国水生生物保护和降低MXC生态风险提供有价值的参考.
As an organochlorine pesticide,methoxychlor(MXC)has been widely used in agriculture,resulting in a high frequency of detection in both the aquatic and sediment environment,and has toxic effects on aquatic species.Therefore,it is critical and necessary to derive Chinese MXC water quality criteria(WQC)and sediment quality criteria(SQC),and perform the ecological risk assessment for protecting aquatic organisms.The acute toxicity data of 17 aquatic organisms and the chronic toxicity data of 10 aquatic organisms were obtained through collection and screening.The best fit of the species sensitivity distribution(SSD)model was selected to derive the WQC,the short-term WQC(SWQC)and long-term WQC(LWQC)of MXC for aquatic organisms were 0.75 μg/L and 0.11 μg/L,respectively.Furthermore,the SQC was derived based on WQC by using the phase-equilibrium parti-tioning method.The resulting SQC-low(SQC-L)and SQC-high(SQC-H)were 0.73 mg/kg and 0.11 mg/kg,respectively.Moreo-ver,the exposure concentration data of MXC in surface waters and sediments were collected,the ecological risk was evaluated by using risk quotients(RQ)method.The result showed that there were certain MXC ecological risk in surface water and sediments.The work will provide a valuable reference for protecting aquatic organisms and minimizing MXC ecological risk in China.