Concentrations and potential health hazards of organochlorine pesticides in (shallow) groundwater of Taihu Lake region, China

Abstract

A total of 27 shallow groundwater samples were collected from the Taihu Lake region (TLR), to determine the concentrations of 14 organochlorine pesticide (OCP) species, identify their possible sources, and estimate health risk of drinking the shallow groundwater. All OCP species occurred in the shallow groundwater of TLR with high detection frequency except p, p'-dichlorodiphenyldichlorothane (p, p'-DDD) and p, p'-dichlorodiphenyltrichloroethane (p, p'-DDT). DDTs and hexachlorocyclohexanes (HCHs) were the dominant OCP contaminants in the shallow groundwater of TLR, and they account for 44.2% total OCPs. The low α-HCH/γ-HCH ratio, high β-HCH/(α+γ)-HCH ratio and β-HCH being the dominant HCH isomers for the majority of samples suggest that the HCHs were mainly from the historical use of lindane after a period of degradation. p, p'-DDE being the dominant DDT metabolite for all the samples indicated that the DDTs were mainly from the historical residues. Compositional analysis also suggested that there were fresh input sources of heptachlors, aldrins and endrins in addition to the historical residues. Correlation analysis indicated the hexachlorobenzene (HCB) impurity in the shallow groundwater of TLR was likely from the historical application of lindane and technical HCH (a mixture of HCH isomers that is produced by photochlorination of benzene). Carcinogenic risk values for α-HCH, heptachlor, heptachlor epoxide, aldrins and dieldrin in the shallow groundwater in majority area of TLR were found to be >10(-6), posing a potentially serious cancer risk to those dependant on shallow groundwater for drinking water.

Keywords: AT; Aldrins; BW; C; CDI; CV; Cancer risk; Composition; DDT; DDTs; ED; EF; Endrins; GC-μECD; HCB; HCH; HCHs; HPLC; HQ; Heptachlors; IR; MDL; OCP; Organochlorine pesticides; POPs; PTFE; PVC; R; R(f)D; S/N; SF; SPE; Shallow groundwater; Source identification; TLR; Taihu Lake region; US EPA; United State Environmental Protection Agency; aldrin and dieldrin; average lifespan; body weight; carcinogenic risk; chemical concentration in water; chronic daily intake; coefficient of variation; dichlorodiphenyltrichloroethane; endrin and endrin aldehyde; exposure duration; gas chromatography equipped with a (63)Ni electron capture detector; hazard quotient; heptachlor and heptachlor epoxide; hexachlorobenzene; hexachlorocyclohexane; high performance liquid chromatography; method detection limit; organochlorine pesticide; p, p′-DDD; p, p′-DDE; p, p′-DDE, p, p′-DDD and p, p′-DDT; p, p′-dichlorodiphenyldichlorothane; p, p′-dichlorodiphenylethane; persistent organic pollutants; polytetrafluoroethylene; polyvinyl chloride; reference dose of the contaminant via oral exposure; signal versus noise value; slope factor of the contaminant via oral exposure route; solid phase extraction; the exposure frequency; water ingestion rate; α-, β-, γ-, δ-isomers.