Occurrence, distribution and risk assessment of polychlorinated biphenyls and polybrominated diphenyl ethers in nine water sources.

Water quality of water sources is a critical issue for human health in South China, which experiences rapid economic development and is the most densely populated region in China. In this study, the pollution of organohalogen compounds in nine important water sources, South China was investigated. Twenty six organohalogen compounds including seventeen polychlorinated biphenyls (PCBs) and nine polybrominated diphenyl ethers (PBDEs) were detected using gas chromatograph analysis. The concentrations of total PCBs ranged from 0.93 to 13.07ngL(-1), with an average value of 7.06ngL(-1). The total concentrations of nine PBDE congeners were found in range not detected (nd) to 7.87ngL(-1) with an average value of 2.59ngL(-1). Compositions of PCBs and PBDEs indicated the historical use of Aroclors 1248, 1254 and 1260, and commercial PBDEs may be the main source of organohalogen compounds in water sources in South China. The nine water sources could be classified into three clusters by self-organizing map neural network. Low halogenated PCBs and PBDEs showed similar distribution in the nine water sources. Cancer risks of PCBs and PBDEs via water consumption were all below 10(-6), indicating the water quality in the nine water sources, South China was safe for human drinking.