The Residue Dynamic And Emilation Effect Of Mixed Pesiticides In The Cabbage

At present,the production of our country's pesticides is developing gradually from single preparations to mixed ones,but in the process of pesticide residue research and pesticides registration management,our country basically only pays attention to the sole preparations.But in produces and in the application reality,the pesticides are often mixed. So it isvery difficult to guarantee the scientific nature of pesticides registration and residue result.Therefore,this article studies following content with emphasis:Choosing 3 kinds of quite commonly used pesticides:Chlorpyrifos,Pyridaphenthion and beta-cypermethrin. The article studies separately the degeneration rules of different kinds of sole and mixed preparations in the cabbage.Then we compared the differences of degeneration rules between sole preparations and mixed preparations.Then we analizied the effects of mixed preparations on sole preparations,then according to the known residual datas,appraisalling the risk of security plastochrone respectively.In the article studies the influences of the different processing methods to the elimination rates of pesticides residue is also mentioned.Then the pesticides risk assessment in the different situation is reaseared and the risk assessment model is established.This experiment mainly draws the following conclusion through more than 2 years of research:1) Through the massive experimental study,foregoing disposal methods and chromatograph examination conditions of 3 kinds of pesticides are established.2) The half-lives of beta-cypermethrin and mixed with Pyridaphenthion,Chlorpyrifos respectively are 0.98d,0.90d and 0.82d.The half-lives of Pyridaphenthion and Pyridaphenthion mixed beta-cypermethrin respectively are 1.19 and 1.09d.The half-lives of Chlorpyrifos and Chlorpyrifos mixed beta-cypermethrin respectively are 1.25d and 1.19d.Form above on,the half-life of beta-cypermethrin in the mixed praparations is obviously longer than that in the sole ones.However,the half-lives of Pyridaphenthion, Chlorpyrifos in the mixed praparations are a little samaller than that of in the sole praparations,but the difference is not big.3) The degeneration speed of pesticides tried is very fast during the first 7 days in the soil and cabbage,afterward tended to be balanced,the resolution dynamic conformed to the first-level dynamic equation,moreover the degeneration speed in the soil is faster than that of in the cabbage.4) During all the pesticides tried,only the beta-cypermethrin residue exceeds the allowed figure after Pre-harvest interval.The beta-cypermethrin residue exceeds national standard(1 mg/kg) for the 3rd day after spraying,because Pre-harvest interval of beta-cypermethrin allowed is 3 days.Pre-harvest interval of beta-cypermethrin has the extension relatively in the fall or winter season.Moreover,the degeneration speed in the mixed preparation is faster than that of in the sole ones.Most obvious by beta-cypermethrin,Chlorpyrifos,Pyridaphenthion taking second place.5) Studies indicated that the storage time is longer,the water temperature to be higher, the detergent density to be bigger,the wash immersion time to be longer,for the elimination rate of pesticides tried is higher respectively.6) The article established the most superior processing combination(combination 1) to eliminate pesticides residue:under 30℃soaks 10min,then clear water washing→the rice water soaks 10min,washes→soaks the 10min latter 0.05%detergent clean.This combination reaches about 70%to the pesticides elimination rate,simultaneously guaranteed the fresh and trophism of the cabbage.7) The diet exposition risk assessment experiment indicated:picked after own Pre-harvest interval,then processed by combines 1,the residual diet amount of absorption is only 2～14%of the ADI value,is only 0.2～1.4%of the ARfD value,therefore.From the edible security angle,eating cabbage dealed with pesticides tried is safe.