title: Historical trends of organochlorine pesticides (OCPs) recorded in sediments across the Tibetan Plateau.
abstract: Sediment cores from four lakes across the Tibetan Plateau were used as natural archives to study the time trends of organochlorine pesticides (OCPs). The total concentrations of dichlorodiphenyltrichloroethane (ΣDDT) and hexachlorocyclohexane isomers (ΣHCH) were in the range of 0.04-1.61 and 0.08-1.88 ng/g based on dry weight (dw), while the input fluxes were in the range of 0.3-236 and 0.7-295 pg/cm2/y in the core sediments, respectively. The input fluxes of ΣDDT and ΣHCH generally peaked in sediment layers corresponding to the 1970s-1990s and peaked in top sediment layers. The ratio of α/γ-HCH decreased in the top layer sediments, implying that the contribution of lindane (pure γ-HCH) has been increasing in recent years. In addition, the ratio of o,p'-DDT/p,p'-DDT increased significantly over the last 15-20 years, suggesting that dicofol (characterized by high ratio of o,p'-DDT/p,p'-DDT about 7.0) has recently become a relatively more important source of DDT compared to technical DDT itself. The time trends of OCPs recorded in lake sediments examined the impact on such remote alpine regions by human activities.
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing, 100085, China. rqyang@rcees.ac.cn.
authors.forename: Ruiqiang
authors.initials: R
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing, 100085, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Xie
authors.affiliation: Environmental Change Research Centre, University College London, Pearson Building, Gower Street, London, WC1E 6BT, UK.
authors.forename: Handong
authors.initials: H
authors.lastname: Yang
authors.affiliation: Environmental Change Research Centre, University College London, Pearson Building, Gower Street, London, WC1E 6BT, UK.
authors.forename: Simon
authors.initials: S
authors.lastname: Turner
authors.affiliation: Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China.
authors.forename: Guangjian
authors.initials: G
authors.lastname: Wu
mesh_terms: D002849:Chromatography, Gas; D003634:DDT / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods*; D019015:Geologic Sediments / Q000737:chemistry*; D001556:Hexachlorocyclohexane / Q000032:analysis*; D007536:Isomerism; D060106:Lakes; D010575:Pesticides / Q000032:analysis*; D018609:Tibet; D013997:Time Factors
chemical_list: D010575:Pesticides; C040534:alpha-hexachlorocyclohexane; D001556:Hexachlorocyclohexane; D003634:DDT
keywords: Alpine lake; DDT; HCH; Historical trend; Sediment core; Tibetan Plateau