title: Organochlorine pesticides in soils under different land usage in the Taihu Lake region, China.
abstract: A field study was conducted in the Taihu Lake region, China in 2004 to reveal the organochlorine pesticide concentrations in soils after the ban of these substances in the year 1983. Thirteen organochlorine pesticides (OCPs) were analyzed in soils from paddy field, tree land and fallow land. Total organochlorine pesticide residues were higher in agricultural soils than in uncultivated fallow land soils. Among all the pesticides, sigmaDDX (DDD, DDE and DDT) had the highest concentration for all the soil samples, ranging from 3.10 ng/g to 166.55 ng/g with a mean value of 57.04 ng/g and followed by sigmaHCH, ranging from 0.73 ng/g to 60.97 ng/g with a mean value of 24.06 ng/g. Dieldrin, endrin, HCB and alpha-endosulfan were also found in soils with less than 15 ng/g. Ratios of p,p'-(DDD+DDE)/DDT in soils under three land usages were: paddy field > tree land > fallow land, indicating that land usage influenced the degradation of DDT in soils. Ratios of p,p'-(DDD+DDE)/DDT > 1, showing aged residues of DDTs in soils of the Taihu Lake region. The results were discussed with data from a former study that showed very low actual concentrations of HCH and DDT in soils in the Taihu Lake region, but according to the chemical half-lives and their concentrations in soils in 1980s, the concentration of DDT in soils seemed to be underestimated. In any case our data show that the ban on the use of HCH and DDT resulted in a tremendous reduction of these pesticide residues in soils, but there are still high amounts of pesticide residues in soils, which need more remediation processes.
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China. wangfang@issas.ac.cn
authors.forename: Fang
authors.initials: F
authors.lastname: Wang
authors.forename: Xin
authors.initials: X
authors.lastname: Jiang
authors.forename: Yong-Rong
authors.initials: YR
authors.lastname: Bian
authors.forename: Fen-Xia
authors.initials: FX
authors.lastname: Yao
authors.forename: Hong-Jian
authors.initials: HJ
authors.lastname: Gao
authors.forename: Gui-Fen
authors.initials: GF
authors.lastname: Yu
authors.forename: Jean Charles
authors.initials: JC
authors.lastname: Munch
authors.forename: Reiner
authors.initials: R
authors.lastname: Schroll
mesh_terms: D002244:Carbon / Q000032:analysis; D002681:China; D004784:Environmental Monitoring; D006843:Hydrocarbons, Chlorinated / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D010573:Pesticide Residues / Q000032:analysis*; D010575:Pesticides / Q000032:analysis*; D012989:Soil Pollutants / Q000032:analysis*
chemical_list: D006843:Hydrocarbons, Chlorinated; D010573:Pesticide Residues; D010575:Pesticides; D012989:Soil Pollutants; D002244:Carbon