| ChaoHu Lake was selected as our case study of OCPs contamination in water. Through the discussion about the origin, tendency and release of OCPs, we can know the transferring and transforming pathways of OCPs in the water in ChaoHu Lake, which may provide theoretical foundation for controlling and treating organic pollution of lakes.This paper investigates the residual levels of OCPs in water from ChaoHu Lake and the lake's tributaries by using solid phase extraction(SPE)and gas-chromatography /electron-caprure detection (GC-ECD). This paper analyzed the residual levels of OCPs in water not only from ChaoHu Lake's surface water and in different depth water of ChaoHu Lake. But also from in water of ChaoHu Lake tributaries, including NanFei river,ShangPai river,FengLe river,HangBu river,ZheGao river and Bai Shi-shan river.Firstly, The concentrations of 19 kinds of OCPs in the surface water of ChaoHu Lake were analyzed by SPE-GC/ECD in this paper. According to the experiment, there were 16 kinds of OCPs detected. Mainly of HCHs, DDTs,β-Endosulfan, Aldrin, Heptachlor, etc. The range of total OCPs concentration was 0.54~64.01ng/L. The results indicated that the main components were HCHs and DDTs, whose average concentration was 5.56 ng/L and 16.57 ng/L, accounting for about 84.75% of the total weight of OCPs. And the primary residual HCHs wereβ-HCH, the content order of isomers of HCHs was:β-HCH>α-HCH>γ-HCH>δ-HCH. It was because thatβ-HCH was very steady and not easy to decomposed and other isomers would transit intoβ-HCH .The origins of OCPs in the watershed were investigated, the values ofα/γin surface water were in the range of 0.46-3.31 and most of them were less than 1. and most values of (DDD+DDE)/DDTs and DDE/DDD in surface water were more than 0.5 and 1. showed that there were historical residues and recent discharges of OCPs into the watershed.Secondly, the distribution and compositon of OCPs in different depth water of ChaoHu Lake were studied. The concentrations of OCPs in bottom water in mostly sample sites were higher than in surfare water, which indicated that OCPs in bottom water were mainly derived from the release of the sediments. OCPs compositions were almost same between surface and bottom water.The concentrations of 19 kinds of OCPs in water of ChaoHu Lake tributaries were analyzed in this paper. Including NanFei river,ShangPai river,FengLe river,HangBu river,ZheGao river and Bai Shi-shan river. According to the experiment, there were 8 kinds of OCPs detected. Mainly of HCHs, DDTs,β-Endosulfan, etc. The range of total OCPs concentration was 1.22~77.10ng/L. The results indicated that the main components were HCHs and DDTs. And the primary residual HCHs wereβ-HCH, The range concentration was 12.57ng/L. the primary residual DDTs were DDE and DDD. The origins of OCPs in the watershed were investigated show that, the same as the surface water of ChaoHu Lake, there were historical residues and recent discharges of OCPs into the watershed.Fourthly, The concentrations of all existences accorded with the target values of GB 3838-2002. Compared with other water bodies throughout the world, the concentrations of OCPs in the water of the ChaoHu Lake are much lower and the risk is low in general. Through the environmental quality assessment and environmental risk Assessment shows that the water of Chaohu Lake watershed of organochlorine pesticides on human health the potential risks of not. And design the water quality model about the transport and transformation of organochlorine pesticides in water of Chaohu Lake watershed, in order to better grasp the characteristics and patterns of income and expenditure, better predict the development trend and the development of better management and planning decision-making to provide strong support for the technology and methods of it.
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