Levels and Chiral Signatures of Organochlorine Pesticides in Urban Soils of Yinchuan, China

In this study, residual level and enantiomeric composition of typical organochlorine pesticides (OCPs) were surveyed in urban soils of Yinchuan, China. The median levels of ∑HCHs and ∑DDTs were 0.852 and 2.24 ng/g, respectively, which suggested little risk for ecological environment and human health in the study area. Both chiral α-HCH and o , p ′-DDT displayed the non-racemic signatures in all samples. The isomer ratios of ∑HCHs and ∑DDTs combined with enantiomer fractions (EFs) of α-HCH and o , p ′-DDT, suggested that contamination source of HCHs derived from historical HCHs (including technical HCHs and Lindane) and that of DDTs originated from old source with the usage of mixed technical DDTs and dicofol.