Distribution, sources, and risk assessment of polychlorinated biphenyls in surface waters and sediments of rivers in Shanghai, China

The distribution, sources, and potential risks of polychlorinated biphenyl (PCB) contamination in the rivers of Shanghai, China were investigated. Fourteen PCB congeners in surface waters and sediments, which were collected from 53 sampling sites, were quantified by gas chromatography-mass spectrometer (GC-MS). The total concentrations of PCBs in the dissolved phase, in particulates, and in sediments ranged from not detected (nd) to 34.8 ng·L^‒1, from 0.76 to 39.71 ng·L^‒1, and from 1.46 to 46.11 ng·g^–1 (dry weight, dw), respectively. The corresponding WHO toxic equivalents (TEQs) of dioxin-like polychlorinated biphenyls (dl-PCBs) ranged between nd–1135.63 pg TEQ·L^–1, 0.02–605.94 pg TEQ·L^–1, and 0.05–432.12 pg TEQ·g^–1 dw, respectively. The penta-CBs, especially PCB 118 and PCB 105, were the dominant congeners in all samples. Principle Component Analysis (PCA) indicated that the PCBs were mainly influenced by a historical accumulation of commercial PCB products, the burning of house coal, and emissions from municipal solid waste incineration (MSWI) and secondary metallurgy industries. The center of Shanghai was significantly affected by PCB contamination, followed by the industrial parklands and suburban towns, while the farmland of Chongming Island was the least affected area. Adverse biological and health effects would be likely in the central urban areas, industrial parks, and residential towns of Shanghai.