Concentrations, enantiomeric compositions, and sources of HCH, DDT and chlordane in soils from the Pearl River Delta, South China

Jun Li, Gan Zhang, Shihuan Qi, Xiangdong Li, Xiangzhi Peng

Research output: Journal article publicationJournal articleAcademic researchpeer-review

225 Citations (Scopus)

Abstract

Concentrations, and enantiomeric compositions of HCH, DDT and chlordane in 74 soils of the Pearl River Delta, South China were investigated. The mean concentrations of HCHs and DDTs descended in the order: crop soils > paddy soils > natural soils. The concentrations (ng/g dw) of p,p′-DDE, p,p′-DDT, p,p′-DDD and o,p′-DDT in crop soils were 0.14-231, 0.07-315, < DL-96.7 and 0.06-73.8, respectively, while those of chlordane were generally below 0.78 for trans-chlordane (TC) and 0.75 for cis-chlordane (CC). Enantiomeric factors (EF value) were determined for o,p′-DDT, α-HCH, TC and CC. Both preferential depletions of (-) enantiomer and (+) enantiomer were observed for o,p′-DDT and α-HCH, indicated by EF values either < 0.5 or > 0.5. An EF value > 0.5 generally suggested a preferential degradation of the (-) enantiomers of both TC and CC. The racemic α-HCH observed in the soils with higher HCH concentrations indicated that the transformation from γ-HCH (e.g. lindane) to α-HCH may be an important process in the soils. The isomer ratios of p,p′-DDT/(DDE + DDD), o,p′-DDT/p,p′-DDT and enantiomeric compositions of o,p′-DDT suggested that both illegal use of technical DDT and the DDT impurity in dicofol may be responsible for the freshly DDT input in the region. The sources of DDTs were drawn by principal component analysis-multiple linear regression (PCA-MLR). The relative contributions of dicofol-type DDT, residues, and fresh technical DDT were estimated to be 55%, 21% and 17%, respectively. In addition, CC was found to degraded faster than TC in soils from the Pearl River Delta. The study demonstrated that the combination of isomer ratios and enantiomeric composition analysis may provide critical information on the potential sources and fate of organochlorine pesticides in soil.
Original languageEnglish
Pages (from-to)215-224
Number of pages10
JournalScience of the Total Environment
Volume372
Issue number1
DOIs
Publication statusPublished - 15 Dec 2006

Keywords

  • China
  • Chlordane
  • DDT
  • Enantiomeric fraction
  • HCH
  • Pearl River Delta
  • Soil
  • Source

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution

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