Dissipation And Residue Of Indoxacarb In Paddy And It ERA In The Paddy Water

In this thesis, Indoxacarb as the object of study, the dissipation of Indoxacarb residue after using was systematically studied, then chose the zebrafish as the receptor of ecological risk assessment in the water environment. Estimated the ecological risk assessment of Indoxacarb from the model prediction and actual monitoring. The results of this study were as follows:(1) Indoxacarb in paddy soil, rice plants, rice straw, rice and haff samples were extracted by acetonitrile, and cleansed by salting out method;the residue of Indoxacarb in paddy water samples were extracted by methylene dichloride. The separation was performed on HP-5capillary column,detected by GC-ECD.The quantification was performed by external standard method. When the concentration of spiked with Indoxacarb standards at0.01,0.10,0.50mg/kg, the spiked recoveries of this method ranged from71.60%to102.70%,the relative standard deviation ranged from1.57%～8.97%.The minimum detectable amounts of Indoxacarb was1.0×10-11g,the minimum detectable concentration of Indoxacarb were all1.0×10-2mg/kg in all kinds of samples of paddy field.(2) Under the natural conditions of HunanChangsha,ZhejiangHangzhou,GuangxiNanning in the years of2010and2011, the dissipation dynamics of Indoxacarb in the paddy water, paddy soil and rice plant all could accord with the one-grade chemical reaction kinetics equation.The dissipation half-life of Indoxacarb in paddy water, soil and rice plants respectively were2.81d-3.17d,7.48d～9.92d and6.42d～7.57d.These results showed that Indoxacarb was a degradable pesticide.(3) According to the experimental results in ChangshaHunan,HangzhouZhejiang,Nanning Guangxi in the years of2010and2011,we recommended the reasonable use standard:applying15%Indoxacarb SC at the paddy growth period twice at a dose of45a.i.g/ha (each applying pesticide interval was7days) to prevent and cure the cnaphalocrocis medinalis;and its safe interval was28days before harvesting.(4) The LC50of15%Indoxacarb SC to zebrafishes respectively were:7.55mg/L at24h,5.38mg/L at48h,4.50mg/L at72h,3.57mg/L at96h. It suggested that:the toxicity of Indoxacarb was moderate toxicity to zebrafishes. (5) Input the parameters of Indoxacarb concerned to the model of GENEEC2.0, got the concentrations of Indoxacarb in paddy field water at different times.Divied the peak concentration of Indoxacarb in paddy field water from GENEEC2.0and the experimental LC50of the15%Indoxacarb SC to zebrafishes at96hours, got the risk quotient was1.17×10-3, less than0.05, it suggested that there was no risk under the conditions of this experiment.(6) By actual monitoring the environmental exposure concentration at different times of Indoxacarb in simulative "paddy field-pond water",divied the environmental exposure concentration and the experimental LC50of15%Indoxacarb SC to zebrafishes at96hours, got the risk quotient was0.44X10-3, less than0.05as well, it suggested that there was no risk under the conditions of this experiment.