Distribution and ecological risk of polychlorinated biphenyls and organochlorine pesticides in surficial sediments from Haihe River and Haihe Estuary Area, China

Polychlorinated biphenyl (PCB) and organochlorine pesticide (OCP) were analyzed in surficial sediments from the Haihe River and Haihe Estuary Area, Tianjin, China. The concentrations of ∑PCBs (the sum of 32 PCB concentrations) and ∑OCPs (the sum of eight OCPs concentrations) in the sediments from this area ranged from n.d. (not detected) to 253 ng g−1 (average value: 66.8 ng g−1) and from 0.997 to 2447 ng g−1 (average value: 738 ng g−1), respectively. Among the OCPs, the range of concentrations of hexachlorocyclohexane and its isomers (HCHs), dichlorodiphenyltrichloroethane and its metabolites (DDTs) and hexachlorobenzene (HCB) were 0.997–1620 ng g−1 (547 ng g−1), n.d. – 155 ng g−1 (18.5 ng g−1) and n.d. – 835 ng g−1 (173 ng g−1), respectively. In general, the concentrations of all persistent organic pollutants (POPs) from the Haihe River were higher than those from the Haihe Estuary Area. Compositional analyses of the POPs indicated that tri-PCBs were dominant in sediment from the Haihe River, while tetra-PCBs and penta-PCBs were identified as being prevalent in the Haihe Estuary Area. In addition, β-HCH and p,p′-DDD were found to be the dominant HCHs and DDTs, respectively. Compared with other areas around the world, the concentrations of POPs in sediments from the Haihe River were higher, but pollution level was comparable with other areas in the Haihe Estuary Area. According to established sediment quality guidelines (SQGs), POPs in this area have potential ecological risk.