title: Determination and assessment of HCHs and DDTs residues in sediments from Lake Dongting, China.
abstract: The contamination of organochlorine pesticides hexachlorocyclohexane (HCH) and Dichlorodiphenyltrichloroethane (DDT) and their eco-environmental assessment in surface sediments from Lake Dongting, the second-largest freshwater lake in China, were studied. Concentrations of summation HCH (=alpha-HCH + beta-HCH + gamma-HCH +delta-HCH) were 0.21-9.59 ng/g dry weight and those of summation DDT = p,p'-DDD+p,p'-DDE+o,p'-DDT+p,p'-DDT) ranged from under detectable limit to 10.15 ng/g dry weight. The ratios of alpha-HCH to gamma-HCH were above 7 at most sampling sites while no or a small amount of beta-HCH were found at all sites, suggesting the degradation of HCH used in the history and possibly current use of HCH in the region. The low ratios (below 2.0 in most cases) of (p,p'-DDE+p,p'-DDD) to p,p'-DDT and high levels of individual isomers of DDT at some sites also suggested that there have still been fresh inputs of DDT into Lake Dongting. Through the comparison between concentrations of HCH and DDT residues in sediments of Lake Dongting and those from other places in China and also from the results of our eco-environmental assessment, it can be concluded that Lake Dongting is the water body with high contamination of both HCH and DDT in its sediments in comparison with other water bodies in China.
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China. xyjqqyy@hotmail.com
authors.forename: Yong
authors.initials: Y
authors.lastname: Qian
authors.forename: Minghui
authors.initials: M
authors.lastname: Zheng
authors.forename: Bin
authors.initials: B
authors.lastname: Zhang
authors.forename: Lirong
authors.initials: L
authors.lastname: Gao
authors.forename: Wenbin
authors.initials: W
authors.lastname: Liu
mesh_terms: D002681:China; D003634:DDT / Q000032:analysis*; D005618:Fresh Water / Q000737:chemistry*; D019015:Geologic Sediments / Q000737:chemistry*; D001556:Hexachlorocyclohexane / Q000032:analysis*; D010573:Pesticide Residues / Q000032:analysis*
chemical_list: D010573:Pesticide Residues; C040534:alpha-hexachlorocyclohexane; C086916:delta-hexachlorocyclohexane; D001556:Hexachlorocyclohexane; D003634:DDT; C023888:beta-hexachlorocyclohexane