Characteristics and Potential Health Hazards of Organochlorine Pesticides in Shallow Groundwater of Two Cities in the Yangtze River Delta

Abstract

A total of 52 shallow groundwater samples were collected from two cities, Shengzhou and Shangyu, in the Yangtze River Delta, to characterize the residues of hexachlorocyclohexane (HCH) isomers and dichlorodiphenyltrichloroethane (DDT) isomers/metabolites present and estimate health risk of drinking groundwater. HCH and DDT residues occurred in the shallow groundwater of most of Shengzhou and partial area of Shangyu. Concentrations of total HCH (ΣHCHs) and total DDT (ΣDDTs) in the shallow groundwater ranged from below the detection limit (BDL) to 123.2 ng L−1 and BDL to 321.4 ng L−1 for Shengzhou and BDL to 46.40 ng L−1and BDL to 77.92 ng L−1 for Shangyu. The predominant HCH and DDT species in the shallow groundwater of Shengzhou were δ‐HCH and o,p′‐DDT, and the equivalent species in Shangyu were δ‐HCH and p,p′‐DDT. The low α‐HCH/γ‐HCH ratio, low (dichlorodiphenylethylene (DDE) + dichlorodiphenyldichloroethane)/ΣDDTs ratio and o,p′‐DDE being the dominant DDT metabolite for the majority of samples collected from Shengzhou suggest that there are fresh inputs of lindane and dicofol mixtures in majority area of Shengzhou. The high ratios of p,p′‐DDT/ΣDDTs in half of the groundwater samples collected from Shangyu suggest that there are fresh inputs of DDT in partial area of Shangyu. α‐HCH, β‐HCH, and γ‐HCH in the shallow groundwater in majority area of Shengzhou are posing serious cancer risks to children (>10−6), and the three HCH isomers in the shallow groundwater of Shengzhou should be controlled urgently and effectively.