Persistent organic pollutants in coastal sediment off South China in relation to the importance of anthropogenic inputs

Surface sediments collected from the coastal region off South China were analyzed for persistent organic pollutants (POPs), including polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs), and organochlorine pesticides (OCPs). The concentrations of BDE-209, Σ₁₂PBDE, Σ₁₅PAH, Σ₇PAH, and Σ₁₁OCP were 0.22 to 26.3, 0.01 to 0.77, 13.9 to 271, 6 to 133, and 0.9 to 104ng/g, respectively. The spatial distribution patterns of PBDEs and PAHs suggested that the eastern coastal region was slightly more contaminated than the western coast. In addition, the concentrations of dichlorodiphenyltrichloroethane (DDT) and its metabolites (DDXs) were highly variable, with the highest level found at a site in Zhanjiang Bay, which might have been reflective of the impact of antifouling paints mainly used in boat maintenance in harbor areas. The predominance of BDE-209 in the study region was consistent with the usage pattern of penta-, octa-, and deca-BDEs in China, whereas sediment PAHs appeared to have been derived largely from coal or wood and petroleum combustion. Preliminary assessments indicated that terrestrial inputs, such as atmospheric transport and riverine runoff, may have been the major input pathways for PBDEs and PAHs, respectively, to accumulate in coastal sediment off South China. Conversely, residues of DDT-containing antifouling paints associated with shipping activities and boat maintenance accounted for most of the accumulated sediment DDTs.