Study on Mechanism of Non-point Source Pollution of Organochlorine Pesticides with Rainfall Simulation Method

By means of rainfall simulation, the mechanism of non-point source pollution of organochlorine pesticides (OCPs)by runoff was studied. The results showed that surface runoff perhaps played a more important role than the seepage water in the migration of OCPs from soil to water. The concentrations of OCPs in the runoff decreased with sampling time and then reached stability after 60 minutes. The soil organic matter affected the trend of migration of OCPs. The concentrations of OCPs in the runoff of the peat soil were relatively high. The total residual OCPs decreased with soil depth. In the depth of 0-5cm, the concentrations of OCPs were the highest. Compared to other soil types, the residual OCPs in the peat soil were lowest. The concentrations of OCPs still were relatively high even after 30 days, suggesting that the degradation of OCPs in the soil was very slow.