Residual characteristics and ecological risk assessment of polychlorinated biphenyls in surface sediments from Yangtze Estuary and nearshore of East China Sea

Concentration of 14 polychlorinated biphenyls (PCBs) residues in sediments from Yangtze Estuary and nearshore of the East China Sea were determined by gas chromatography-electron capture detector (GC-ECD). The concentration of PCBs in sediments were in the range of 18.66-87.31 ng·g^-1. This paper will discuss PCB polluted sediments in the research area in terms of the distribution of PCBs, the pollution level, and the PCBs sources. According to component analysis, the types of PCBs found in the surface sediments were mainly 3 & 4 CB PCBs, accounting for 32.49%-96.43% of the total PCBs found. The principal factor analysis revealed that the PCBs in the sediments were mainly from industrial pollution. Correlation analysis revealed total organic carbon (TOC) content strongly influenced the distribution of OCPs in sediments. Compared with other regions around the world, the pollution level of PCBs was, in general, at a moderate level. The ecological risk assessment by the methods of calculating toxic equivalent quantity (TEQ_PCB) and comparing with interim sediment quality guideline (ISQG) and probable effect level (PEL) values of risk evaluation, indicates the PCB contaminated sediments from Yangtze River estuary and its nearshore of the East China Sea will have a medium ecological risk.