Residues and enantiomeric profiling of organochlorine pesticides in sediments from Yueqing Bay and Sanmen Bay, East China Sea

Abstract

The spatial distributions and chiral signals of organochlorine pesticides (OCPs) in surface sediments from Yueqing Bay and Sanmen Bay, East China Sea were investigated. The total OCPs concentrations ranged from 2.11 to 18.15 ng g −1 dry weight for all the sampling stations. HCHs and DDTs were dominant, although trans-chlorodane/ cis-chlorodane were also observed in some sites. The predominant β-HCH and the α-HCH/ γ-HCH ratios indicated that the residues of HCHs in these places mainly originated from the historical usage of technical HCH. However, the ratios of (DDE + DDD)/DDT reflected a cocktail input pattern of fresh and weathered DDTs. Based on ERL/ERM guidelines, p, p′-DDT and ΣDDT posed a small risk to the bottom-dwelling consumers, while p, p′-DDD, p, p′-DDE and Σchlorodane were not found at concentrations expected to adversely affect sediment biota. Enantiomeric analysis showed that the degradation of chiral OCPs was enantioselective, resulting in enrichment of (−)-enantiomers for α-HCH, o, p′-DDT and o, p′-DDD in all samples. These results implied that the sediment quality guidelines of chiral OCPs should be reassessed using concentrations of their individual enantiomers.