title: Vertical distributions of organochlorine pesticides and polychlorinated biphenyls in an agricultural soil core from the Guanzhong Basin, China.
abstract: The concentrations and distributions of hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes (DDTs), and polychlorinated biphenyls (PCBs) in an agricultural soil core in the Guanzhong Basin, China were determined. Overall, p,p'-DDT and p,p'-DDE were dominant contaminants and accounted for approximately 48.4 and 23.3% of the total detected DDTs. Low chlorinated PCBs (PCB 28 and PCB 52) were generally detected at higher concentrations and more frequently than high chlorinated PCBs. The peak values of ∑DDT (12.92 ng/g), ∑HCH (2.25 ng/g), and ∑PCB (3.44 ng/g) occurred in the 10-15, 15-20, and 5-10 cm sections, respectively. The negative correlation between the organochlorine pesticide (OCP) concentrations and the soil depths and the relatively high p,p'-DDT/p,p'-DDE ratios in the surface soils indicated that these chemicals were recently used illegally, despite their official ban in 1983. The increase in the ratio of α-/γ-HCH with increasing soil depth indicated that the use of lindane decreased relative to the use of technical HCHs in recent years.
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710075, China, luhx@ieecas.cn.
authors.forename: Hongxuan
authors.initials: H
authors.lastname: Lu
authors.forename: Weiguo
authors.initials: W
authors.lastname: Liu
mesh_terms: D000383:Agriculture; D002681:China; D003634:DDT / Q000032:analysis; D003633:Dichlorodiphenyl Dichloroethylene / Q000032:analysis; D004784:Environmental Monitoring; D001556:Hexachlorocyclohexane / Q000032:analysis; D006843:Hydrocarbons, Chlorinated / Q000032:analysis; D010575:Pesticides / Q000032:analysis*; D011078:Polychlorinated Biphenyls / Q000032:analysis*; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis*
chemical_list: D006843:Hydrocarbons, Chlorinated; D010575:Pesticides; D012987:Soil; D012989:Soil Pollutants; C009407:2,5,2',5'-tetrachlorobiphenyl; C040534:alpha-hexachlorocyclohexane; D003633:Dichlorodiphenyl Dichloroethylene; D001556:Hexachlorocyclohexane; C081766:2,4,4'-trichlorobiphenyl; D003634:DDT; D011078:Polychlorinated Biphenyls