PCBs residues characteristic and ecological risk assessment in the water and sediment of Qin Huai River in Nanjing

14 kinds of PCBs were determinded in water and sediment of Qin Huai River in Nanjing, P.R.China. The results showed that: the concentration range of ΣPCBs in the water of the river was 19.56~843.22 ng/L, their mean content was 170.19 ng/L; the concentration range of PCBs in the sediment was 125.80~1714.84 ng/g, and their mean content was 718.45 ng/g. Compared with the rest of the world river, PCBs residual levels in the study area were at the middle level, and the distribution varied widely in different sample sites. The source of pollution most came from the main city beside the input of the upstream. The dominant components of PCBs were tri-, tetra-, and pentachlorinated PCB congeners, such as PCB₁₈, PCB₅₂, PCB₄₄, PCB₁₀₁, PCB₁₁₈, etc, accounting for 91.10%~99.77% of total PCBs residual amount in water or sediment. The potential ecological risk index was 2873.8, and it indicated that the risk of research area was strong. Accounting for the accumulation of the toxic effects of the PCBs, the threat of PCBs to the downstream could not be ignored.