Residue Dynamics and Safety Evaluation of Chlorpyrifos in Apple and Soil

The field experiment and laboratory testing were conducted to reveal the degradation dynamics and the final residues of chlorpyrifos in apple and soil.The results showed that the half-life of chlorpyrifos was 6.9~8.0 days and 4.8~6.2 days in apple and soil respectively,and over 87% degraded on the 21st day in apple and on the 14th day in soil after application.When sprayed 3~4 times with 267 mg a.i./kg and 400.5 mg a.i./kg chlorpyrifos 40% ME,and the last application was 14 days before harvesting,the residue of chlorpyrifos in apple was lower than 1 mg/kg(MRL),and 14 days were recommended as the preharvest interval of chlorpyrifos for apple.