Profiles and Risk Assessment of Organochlorine Pesticides in Three Gorges Reservoir, China

The environmental pollution of the Three Gorges Reservoir in China may not be desirable and has adverse effects on biodiversity and human health in this region. Concentrations of 16 organochlorine pesticides (OCPs) were investigated in 19 surface water samples collected from near dam region of the Three Gorges Reservoir. The concentrations of total OCPs ranged from 14 to 88 ng L-1 with a geometric mean of 23 ng L-1. The spatial distribution of OCPs concentrations indicated the giant reservoir was sink of OCPs for upstream as well as source for downstream. The mean concentrations of total hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) were 10 and 9.7 ng L (1), respectively. Historical use of lindane and DDT was found to be the primary source of HCHs and DDTs. The ratio between heptachlor and its metabolic products indicated new input of heptachlor occurred in this region. Among the 16 detected OCPs, the cancer risks for human of heptachlor and heptachlorepoxide were all above 10(-4), indicating a potential threat of the two OCPs to human health.