Residue behavior and dietary intake risk assessment of kresoxim-methyl and procymidone in strawberry under greenhouse conditions

To understand the residue behavior and possible dietary intake risk of kresoxim-methyl and procymidone applied to greenhouse grown strawberry(Fragaria ananassa Duch.), residue experiment and dietary intake risk assessment to different populations were carried out at Beijing, China. A simple, rapid analytical method for the determination of fungicide residues in strawberry samples was developed using gas chromatography coupled with mass spectrum detection(GC-MSD). The samples were extracted by acetonitrile,purified on primary secondary amine(PSA), analyzed by the GC-MSD. The target analytes were quantified by external standard method. The solar greenhouse trials were carried for 3 times during 2012-2013.The results indicated that the dissipation rate of the studied fungicides in strawberry fruits samples followed first order kinetics. The dissipation curves were c=0.804 7ｅ-0.114twith half-life of 6.1days for kresoxim-methyl, and c=3.283 9ｅ-0.098t with half-life of 7.1 days for procymidone. The residues in strawberry fruits varied from 0.09-1.52 mg/kg for kresoxim-methyl and 0.12-5.81 mg/kg for procymidone, respectively, when two fungicides were applied with kresoxim-methyl at 97.5 g a.i/hm2 or 195 g a.i/hm2, and procymidone at 375 g a.i/hm2 or 750 g a.i/hm2, spray 2 or 3 times, and 1,2,3,5 d PHI(preharvest interval) were set. The risk assessment adopt the RQ(risk quotient) for chronic risk and RP(risk probability) for acute risk, respectively. The results indicated that the RQ and RP values were below than 1 or 100% for the people age of 2-6, 7-14, 18-30 and 60-70 with 1-5 d PHI, which means the risk to consumers is acceptable.