The Distribution Characteristics of 22 Organochlorine Pesticides in Soil from Sample Areas of the Yangtze River Delta

In order to evaluate the agricultural ecological environment risk caused by industrialization over a long period of time, the distribution characteristics of 22 organochlorine pesticide residues in the soils under different land use forms from four perpendicular profiles were analyzed using gas chromatography.Research results indicate that the mean concentrations of OCPs were in the order:vegetable land in industrial park(139.87 ng/g)> waste land in industrial park(103.1 ng/g)> vegetable land in agricultural areas(26.27 ng/g)> paddy field in agricultural areas(2.50 ng/g).DDTs and HCHs were still the primary pollutants of OCPs in the topsoils with DDTs concentrations of 0.14-485.73 ng/g(mean 44.43 ng/g) and HCHs concentrations of 0.69-66.69 ng/g(mean 7.73 ng/g).The ratio of(DDD+DDE)/DDTs indicated that there was almost no new input of pollution in this area.The concentrations of DDTs and HCHs tend to decrease gradually with the increase in the depth of soil profile.This trend is related to the fact that the rock types of zone of aeration in profile soil are mainly clays and sub-clays, which reduce the vertical transfer dynamics of organochlorine pesticides induced by the overland runoff.This study provides some references to the control and improvement of pollution conditions in the region.