Distribution and risk assessment of organochlorine pesticides (OCPs) in soils of typical agricultural regions in Xinjiang

To enhance pollution prevention and control of organochlorine pesticides (OCPs)，the extent of organochlorine pesticides contamination in typical agricultural regions in Xinjiang was investigated in the paper. Surface soil samples from Xinjiang were collected and analyzed for obtaining the residual levels of 15 OCPs. The concentrations were in the ranges of 0.37-22.82 ng/g for HCHs, 0.91-858.47 ng/g for DDTs, 0.15-47.08 ng/g for chlordane-associated compounds, N.D (not detected) -16.27 ng/g for endosulfan and N.D-73.83 ng/g for endosulfan sulfate. Analysis of the sources of contamination showed that HCHs in the area were derived from an old mixed source of technical HCHs and lindane. DDTs, which were suspected to have recent application to the soil in most sites, were derived mainly form a mixture of technical DDTs and dicofol containing DDT impurites, and that chlordanes have new input while endosulfan have few new resources. Five principal components were extracted from 15 components by principal component analysis, accounting for 79.93% of the 15 OCPs tested suggesting that the occurrence of pests and diseases, the application of different OCPs and the components of the pesticides, were all reflected by the messages contained in the principal components. The gray correlative analysis assessment was used to evaluate pollution level of OCPs, the results showed that the pollution level of Shihezi was the highest, and that further measures of pollution control should be taken in all regions.