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 agri? cultural activities, the joint toxicity of their complexes on Vibrio fischeri was studied. The EC50(median effective concentration)was calcu? lated with the acute toxic effects of binary complex contamination on Vibrio fischeri employing different exposure times. The Mixtures Toxic? ity Index method was employed to evaluate the joint toxicity. The acute toxicity experiments showed that the EC50 of copper, cadmium, car? tap, 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 car? tap 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.