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Distribution tendency and source identification of organochlorine pesticides in soils of an underground river catchment |
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Abstract In order to study the distribution tendency and main possible sources of organochlorine pesticides (OCPs) in Qingmuguan underground river catchment in Chongqing, the concentrations of OCPs residues in 17 topsoil samples were measured by gas chromatography equipped with miro-63Ni electron capture detector. The total OCPs concentrations in soils of Qingmuguan ranged from 7.29 to 222.42ng/g with an average value of 46.15ng/g. HCHs and DDTs existed in all samples. The concentrations of HCHs ranged from 0.55 to 26.54ng/g, wihle the concentration of DDTs ranged from 4.31 to 213.50ng/g. The detectable rate of HCB was 88%, and the concentrations of HCB ranged from n.d. to 1.78ng/g. HCHs in study area came from industrial HCHs and lindane, meanwhile, the compositions of HCH isomers has changed significantly under the impact of environment. There were still fresh inputs of DDTs to soils in Qingmuguan underground river catchment, which substantially originated from illegal use of industrial DDTs rather than the dicofol type of DDT. HCB was a kind of persistent organic pollutants which widely existed in soils of Qingmuguan, and mainly being produced by the regional air deposition in recent years. Compared to the similar researches in other areas in China, HCHs and DDTs residues in the soil of Qingmuguan presented low levels. Furthermore, They were higher than those of Germany, Egypt, Romania when compared with parallel researches worldwide.
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Received: 23 June 2011
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