农药和重金属复合污染物对大型溞的毒性效应

农药和重金属作为水环境中两类常见的污染物，其复合污染已经对水体生态和人类生存环境构成严重威胁。作者研究了3种常用农药（毒死蜱、三唑磷、氟虫腈）及2种常见重金属（铅、镉）对大型溞的急性毒性，同时采用五因素五水平二次通用旋转组合设计方案，研究了复合污染物体系对大型溞的联合毒性效应。结果表明:毒死蜱、三唑磷、氟虫腈、铅离子和镉离子对大型溞的48 h-EC50值分别为6.30、7.27、2.17、454.97和1 175.74 μg/L；5种污染物对大型溞的毒性效应贡献值依次为镉离子 > 三唑磷 > 氟虫腈 > 毒死蜱 > 铅离子；复合污染物对大型溞的毒性呈现出一定的相加效应；当水中毒死蜱质量浓度为0.81 μg/L、三唑磷为17.22 μg/L、氟虫腈为5.65 μg/L、铅离子为83.75 μg/L、镉离子为3 793.15 μg/L时，复合污染物毒性的理论协同效应最大。研究结果可为复合污染物风险评估提供参考。

Combined toxicity of pesticide and heavy metal to Daphnia magna

Pesticides and heavy metals are two common types of pollutants in aquatic environment. The combined pollution is noteworthy because they posed a serious threat to aqua ecology and living environment for human. Herein, the acute toxicities of 3 common pesticides (chlorpyrifos, triazophos and fipronil) and 2 common heavy metals (Pb and Cd) to Daphnia magna were evaluated. Their combined toxicities were also studied using five-factor quadratic general rotary unitized design. The 48 h-EC50 values of chlorpyrifos, triazophos, fipronil, Pb2+ and Cd2+ to D. magna were 6.30, 7.27, 2.17, 454.91 and 1 175.74 μg/L, respectively. The contribution of these five pollutions to combined toxicological effects following the order: Cd2+ > triazophos > fipronil > chlorpyrifos > Pb2+. Combined effects of five pollutants was observed on the survival of D. magna. Moreover, the maximum theoretical synergy appears when chlorpyrifos was 0.811 μg/L, triazophos concentration was 17.22 μg/L, fipronil was 5.65 μg/L, Pb2+ was 83.75 μg/L and Cd2+ was 3 793.15 μg/L. The data of this study can provide support for the risk assessment of composite pollutants.