杀螟丹、螺虫乙酯和铜镉二元复合污染的联合毒性

针对农业活动中广泛使用的杀螟丹、螺虫乙酯和常见重金属污染物铜、镉,以费氏弧菌为受试生物研究污染物并存状态下的联合毒性。通过研究在不同暴露时间下二元复合污染对费氏弧菌的急性毒性效应,计算半数效应浓度EC_(50),并采用混合毒性指数法评价联合毒性。研究表明,铜、镉、杀螟丹、螺虫乙酯单一暴露于费氏弧菌15 min的EC_(50)分别为0.53、0.74、79.06 mg·L~(-1)和116.67 mg·L~(-1)。杀螟丹和重金属的混合体系对费氏弧菌的联合毒性主要表现为相加作用,当螺虫乙酯在混合体系中占比较低时,也表现为部分相加作用。杀螟丹和螺虫乙酯能够减缓金属离子进入细胞的速率,因此费氏弧菌急性毒性实验研究联合毒性时,暴露时间应延长至45 min以上。

Joint toxicity of binary complexes of cartap, spirotetramat, copper, and cadmium to Vibrio fischeri

In view of the widespread use of cartap, spirotetramat, and common heavy metal pollutants, such as copper and cadmium in agricultural activities, the joint toxicity of their complexes on Vibrio fischeri was studied. The EC₅₀ (median effective concentration)was calculated with the acute toxic effects of binary complex contamination on Vibrio fischeri employing different exposure times. The Mixtures Toxicity Index method was employed to evaluate the joint toxicity. The acute toxicity experiments showed that the EC₅₀ of copper, cadmium, cartap, and spirotetramat on Vibrio fischeri at 15 mins was 0.53, 0.74, 79.06 mg·L^-1, and 116.67 mg·L^-1, respectively. The joint toxicity of cartap and heavy metals on Vibrio fischeri was mainly additive. When the spirotetramat accounted for a low proportion in the binary mixtures, the joint toxicity was partially additive. The presence of cartap and spirotetramat may slow down the rate of metal ions entering the cell. Therefore, the study of exposure time for joint toxicity on Vibrio fischeri should be extended to 45 mins.