Assessment of Organochlorine Pesticide Residues in Water, Sediment, and Fish of the Songhua River, China

This study examined residual concentrations and associated ecological risks of the organochlorine pesticides (OCPs) hexa- chlorocyclohexane (HCH) and dichloro-diphenyl-trichloroethane (DDT) in water, sediment, and fish of the Songhua River in Zhaoyuan County, China. In June 2012, 10 water, 10 sediment, and 20 fish samples were collected. Residual concentrations of ΣHCH and ΣDDT ranged from 10.0–35.59 ng L−1 (mean 28.03 ± 11.66 ng L−1) and 5.12–39.66 ng L−1 (mean 32.36 ± 11.58 ng L−1) for water. Residual concentrations of ΣHCH and ΣDDT ranged from 0.52–3.00 ng g−1 (mean 2.04 ± 0.73 ng g−1) and 0.34–3.41 ng g−1 (mean 2.38 ± 0.92 ng g−1) for sediment. The ratios of α-HCH/γ-HCH were close to 1 at the majority of sampling points, indicating considerable new pollution from the use of lindane. The ratios of p,p′-DDE + p,p′-DDD/ΣDDT were less than 0.5, indicating recent inputs from DDT impurities in dicofol. All HCH and DDT isomers except for p,p′-DDD were detected in fish tissue samples, but the associated ecological risks were estimated to be below levels of concern. The study revealed a historical usage of OCPs in the Zhaoyuan section of the Songhua River and new OCP from the use of lindane and dicofol.