The Toxic Effects Of Four Herbicides On Misgurnus Anguillicaudatus And Para Misgurnus Anguillicaudatus(Sauvage)

We studied the acute toxicity effect,physiological toxicity effect and genetic toxicity effect of four kinds of herbicide on Misgurnus anguillicaudatus and Paramisgurnus dabryanus (Sauvage) through a cuople of toxicological methods.Acute toxicity test was applied to determine the LC50 (medium lethal concentration) and SC(safe concentration) of the herbicide on the loach. Biochemical status of two kinds of enzyme relating to liver damage was measured to evalute the physiological toxicity effect.And we further used SCGE(Single Cell Gel Electrophesis) technique to test DNA damage in order to study the toxicity effect of the herbicide generally,which also,we hope,can provide scientific basis for monitoring the contaminating of the herbicide to environment and using herbicide properly.Through acute toxicity test,the SCs and LC50s of 24h,36h and 48h are acqured.The LC50s of 24h,36h and 48h of quizalofop-p-ethyl on Misgurnus anguillicaudatus are 0.0736 ml.L^-1,0.0685 ml.L^-1 and 0.0661 ml.L^-1 respectively,and the SC of quizalofop-p-ethyl on Misgurnus anguillicaudatus is 0.016 ml.L^-1. The LC50s of 24h,36h and 48h of Paraquat on Misgurnus anguillicaudatus are 0.723 ml.L^-1,0.660 ml.L^-1 and 0.648 ml.L^-1 respectively,and the SC of Paraquat on Misgurnus anguillicaudatus is 0.156 ml.L^-1. The LC50s of 24h,36h and 48h of Trifluralin on Misgurnus anguillicaudatus are 0.0697 ml.L^-1,0.0654 ml.L^-1 and 0.0625 ml.L^-1 respectively,and the SC of Trifluralin on Misgurnus anguillicaudatus is 0.0151 ml.L^-1. The LC50s of 24h,36h and 48h of green onion herbicide on Misgurnus anguillicaudatus are 0.038 ml.L^-1,0.027 ml.L^-1 and 0.022 ml.L^-1 respectively,and the SC of green onion herbicide on Misgurnus anguillicaudatus is 0.0023 ml.L^-1.The LC50s of 24h,36h and 48h of quizalofop-p-ethyl on Paramisgurnus dabryanus (Sauvage) are 0.0747 ml.L^-1,0.0645 ml.L^-1 and 0.0611 ml.L^-1 respectively,and the SC of quizalofop-p-ethyl on Paramisgurnus dabryanus (Sauvage) is 0.0123 ml.L^-1. The LC50s of 24h,36h and 48h of Paraquat on Paramisgurnus dabryanus (Sauvage) are 0.710 ml.L^-1,0.660 ml.L^-1 and 0.614 ml.L^-1 respectively,and the SC of Paraquat on Paramisgurnus dabryanus (Sauvage) is 0.138 ml.L^-1. The LC50s of 24h,36h and 48h of Trifluralin on Paramisgurnus dabryanus (Sauvage) are 0.0672 ml.L^-1,0.0613 ml.L^-1 and 0.0591 ml.L^-1 respectively,and the SC of Trifluralin on Paramisgurnus dabryanus (Sauvage) is 0.0137 ml.L^-1. The LC50s of 24h,36h and 48h of green onion herbicide on Misgurnus anguillicaudatus are 0.032 ml.L^-1,0.024 ml.L^-1 and 0.020 ml.L^-1 respectively,and the SC of green onion herbicide on Paramisgurnus dabryanus (Sauvage) is 0.0025 ml.L^-1.Based on the results of the acute toxicity test, five experiment groups of different concentration levels and a control group were designed for physiological toxicity test. In the physiological toxicity test,the activity of GPT and GOT was measured.The results showed that four kinds of herbicide all could induce the increse of the GPT and GOT activity in different levels,from which we conclude that the liver of Misgurnus anguillicaudatus and Paramisgurnus dabryanus (Sauvage) was damaged by the herbicide and four kinds of herbicide have physiological toxicity effect. But we also found that as time of experiment went on ,the GPT and GOT activity all decresed finally.To further explore the DNA damage effect of the herbicide we studied, SCGE technique was applied. The results showed that quizalofop-p-ethyl, Paraquat and green onion herbicide all could induce DNA damage of different levels. But as time of experoment went on, the DNA damage levels of several experiment groups decreased. This may be caused by the activating of DNA repair system. The results also showed that Trifluralin had no DNA damage effect on Misgurnus anguillicaudatus. As for Paramisgurnus dabryanus (Sauvage), Trifluralin had little DNA damage effect on it and the DNA damage levels did not change significantly as time and concentration increased,from which we concluded that other factors, for example sunlight,may result this damage. In conclusion, quizalofop-p-ethyl, Paraquat and green onion herbicide have genetic toxicity effect on Misgurnus anguillicaudatus and Paramisgurnus dabryanus (Sauvage) and the genetic toxicity effect of Trifluralin need to be further studied.In the embryo toxicity test,four kinds of herbicide all can reduce the hatching rate of Misgurnus anguillicaudatus and Paramisgurnus dabryanus (Sauvage). And quizalofop-p-ethyl, Paraquat and green onion herbicide all can induce malformation embryos and have teratogenic effect on the tested organisms. Trifluralin,however,has no teratogenic effect on Misgurnus anguillicaudatus and Paramisgurnus dabryanus (Sauvage).