title: Risks from sediments contaminated with organochlorine pesticides in Hangzhou, China.
abstract: In September 2009, we investigated the residues, enantiomer fractions (EFs) and biological risks of organochlorine pesticides (OCPs), including dichlorodiphenyltrichloroethanes (DDTs) and hexachlorocyclohexanes (HCHs), in three different depth ranges (0-5 cm, 5-10 cm and 10-15 cm) of sediments from 15 sites in Hangzhou, China. The concentration (ng g(-1) dryweight) ranges of HCHs and DDTs in surface sediments were 0.74-5.8 and 0.76-17, respectively. The vertical distribution of mean OCP concentrations was in the order of 10-15 cm>5-10 cm>0-5 cm and implied that the residues of HCHs and DDTs gradually decreased after they were banned. The residues of OCPs in the study area mainly originated from the historical OCP use. The isomer ratios of <alpha>-HCH (α-HCH)/<gamma>-HCH (γ-HCH) (0.10-7.6) implied that HCH residues were derived not only from historical technical HCH use but also from additional use of lindane in this area. The isomer ratios of o,p'-DDT/p,p'-DDT (51% of samples were in the range of 0.3-1.3) suggested that both dicofol-type DDT and technical DDT applications may be present in most study areas. The (+)-enantiomers of α-HCH and o,p'-DDT were more prevalent than (-)-enantiomer in most samples with the fractions contain different enantiomers greater than 0.5. DDTs, especially p,p'-DDE, are the main OCP species of more ecotoxicological concern in Hangzhou.
authors.affiliation: International Joint Research Centre for Persistent Toxic Substances (IJRC-PTS), Zhejiang University of Technology, Hangzhou 310032, China.
authors.forename: Chengwang
authors.initials: C
authors.lastname: Wu
authors.forename: Anping
authors.initials: A
authors.lastname: Zhang
authors.forename: Weiping
authors.initials: W
authors.lastname: Liu
mesh_terms: D002681:China; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000737:chemistry*; D006843:Hydrocarbons, Chlorinated / Q000032:analysis*; D010575:Pesticides / Q000032:analysis*; D018570:Risk Assessment; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014877:Water Pollution, Chemical / Q000706:statistics & numerical data
chemical_list: D006843:Hydrocarbons, Chlorinated; D010575:Pesticides; D014874:Water Pollutants, Chemical