The Joint Toxic Effects Study Of Three Pesticides To Acetylcholinesterase

Through the study for the IC50of five kinds of single pesticide for chlorpyrifos, phoxim, carbaryl, methomyland, cyhalothrin to acetylcholinesterase preparation, and according to the IC50of five kinds single pesticide at24min, further study the joint toxicity of three composite pesticide for chlorpyrifos combine with carbaryl, chlorpyrifos combine with methomyl and phoxim combine with cyhalothrin to AChE under the condition of the different time points, the different toxicity ratio and different concentrations, and studied the dose-effect relationship. At the same time, the study for the LC50of acute toxicity of five single pesticides to zebrafish and toxicity effects on zebrafish head AChE; on this basis, further study the joint acute toxicity to zebrafish and the joint toxicity effects on zebrafish head AChE of three pairs composite pesticides when toxicity ratio is1:1. The conclusion of experiment as follows:1. Through the study for the vitro toxicity effect of chlorpyrifos, phoxim, carbaryl, methomyland, cyhalothrin to AChE preparation, determination the IC50of five single pesticide to AChEpreparation in24min were1.5026,0.7184,0.7752,0.0908and32.938mg/L.2. In vitro, the joint toxicity effects of chlorpyrifos combine with carbaryl to AChE preparations didn't change with time change under the same toxicity ratio, but at the same time, the joint toxicity effects were different under the different toxicity ratio, shown as additive or synergistic.In vitro, the joint toxicity of chlorpyrifos combine with methomyl and phoxim combine with cyhalothrin changed with time change under the same toxicity ratio, and at the same time, the joint toxicity effects were different under the different toxicity ratio, shown as additive or antagonism.3. At the same concentration, the joint toxicity effect in vitro of phoxim combine with cyhalothrin to AChE showed that the inhibition rate increased with the decreased of pesticide concentration; the toxicity effect in vitro for other single and composite pesticide to AChE showed that the inhibition rate decreased with the decreased of pesticide concentration. At the same concentration, the rules of toxic effect of various pesticides to AChE were different with the extension of time, but most showed that the inhibition rate decreased before they were stable with the extension of time.4. The results showed that the acute toxicity of chlorpyrifos, phoxim, carbaryl, methomyl and cyhalothrin to zebrafish were high toxicity, medium toxicity, low toxicity, high toxicity, severe toxicity according the "semi static method" of acute toxicity test on zebrafish for the OECD recommended. The joint acute toxicity of chlorpyrifos combine with carbaryl to zebrafish showed addition in the test process of exposure. The joint acute toxicity of chlorpyrifos combine with methomyl and phoxim combine with cyhalothrin to zebrafish were different at different exposure time, shown as antagonism or additive.5. The study have showed that the activity of AChE for five single pesticide concentration group had Inhibition significantly, and the inhibition decreased with the decreased of concentration, after zebrafish exposure in various concentrations of chlorpyrifos, phoxim, carbaryl, methomyl and cyhalothrin. The joint toxic effects of chlorpyrifos combine with carbaryl, chlorpyrifos combine with methomyl and phoxim combine with cyhalothrin to AchE in zebrafish head were addition, antagonism and addition. The AChE activity in zebrafish head had inhibition significantly after three of the composite pesticide exposed, and the inhibition decreased with reduced of pesticide concentrations. All the AChE activity of additives control (SCK) group had no significant difference compared with and the control group,the results showed that additives had no significant effect on AChE activity in zebrafish head.