Residue Risk Assessment Of Chlorfenapyr On Actinidia Chinensis

In order to ensure the safety of 240g/L chlorfenapyr suspension on kiwifruit(Actinidia Chinensis),a field experiment of 240g/L chlorfenapyr suspension in kiwifruit was carried out in Xianyang,Shaanxi,Yongcheng,Henan,Suzhou,Anhui,Lichuan,Hubei,Jiulongpo,Chongqing,and Guiyang,Guizhou in 2018.A method for the analysis of residues in kiwifruit was established in this study.The final residue of chlorfenapyr in the whole fruit and pulp matrix of kiwifruit and the digestion dynamics in whole fruit were studied,and the dietary risk assessment of chlorfenapyr in kiwifruit was established.This dissertation provides a scientific and rational basis for the use of 240g/L chlorfenapyr suspension on kiwifruit;in addition,the effects of three primary processing processes on the residues of chlorfenapyr in kiwifruit were studied.The specific test results are as follows:(1)A simple method for determination of chlorfenapyr residues in kiwifruit was established by gas chromatography-tandem mass spectrometry.When the concentration was 0.005,0.5,0.05 mg/kg,the average recovery rates of chlorfenapyr were 90.9%-94.9%in whole fruit,85.8%?99.0%in pulp,and the relative standard deviation was 2.5%?9.9%in whole fruit.,4.8%?9.9%in pulp;the average recovery rates of processed products such as jam,juice,dried fruit and pomace were 95.2%?103.8%,84.1%?94.9%,92.6%?96.3%,83.5%?110.0%,and the relative standard deviation was 2.4%?9.9%,5.9%?7.2%,1.9%?9.5%,and 3.8%?9.6%,respectively.(2)The dissipition dynamics of chlorfenapyr in kiwifruit in Anhui and Hubei accords with the first-order chemical kinetic equation.The degradation equation of chlorfenapyr in kiwifruit was y=1.0433 e-0 0425 x(R2=0.9896)and the half lives was 16.3 days in Anhui.The degradation equation of chlorfenapyr in kiwifruit was y=0.9985 e-0 0549x(R2=0.9982)and the half lives was 12.6 days in hubei.(3)As 10 days,14 days and 21 days after application,the terminal residues of chlorfenapyr were from 0.126 to 2.934mg/kg in kiwifruit whole fruit and<0.005 to 0.237mg/kg in pulp when applied at a dose of 120 mg a.i./kg(formulation amount 20 g/mu),180 mga.i./kg(formulation amount 1333 times solution)that of 240g/L chlorfenapyr suspension concentrate with spraying 2 or 3 times at an interval of 7 days.This dissertation gives the rational application of chlorfenapyr suspension in kiwifruit according to the results:the dosage was 120 mg a.i./kg,sprayed three times with spraying interval of 10 days.(4)Under good agricultural practices,the supervised trials median residuel median(STMR)of chlorfenapyr in kiwifruit pulp is 0.0255mg/kg;the national estimated daily intakes(NEDIS)of chlorfenapyr were 0.011?0.093 ?g/(kg bw·d)for all groups of Chinese residents,the risk quotient(RQ)were 0.02%?0.31%.The results showed that the risk of dietary intake of chlorfenapyr in kiwifruit was low in all age groups in China.(5)The effects of three processes of extracting,cooking and drying on the insecticidal nitrile in kiwifruit were compared.The juice extraction process can effectively reduce the residual amount of insect nitrile,and most of the insect nitrile will remain in the filtered pomace;The cooking process of making kiwi jam can also effectively reduce the residual amount of chlorfenapyr,and the degradation degree of chlorfenapyr will increase with the increase of cooking time;for the hot air drying process of making kiwi fruit stem,due to a large amount of water loss Significantly increase the content of insect nitrile.