PCBs, PCNs and PBDEs in sediments and mussels from Qingdao coastal sea in the frame of current circulations and influence of sewage sludge

Influence of current circulation and sewage sludge on spatial distributions of polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), and polybrominated diphenyl ethers (PBDEs) in sediments and mussels from the Qingdao coastal sea were investigated. Total concentrations of PCBs, PCNs and PBDEs in sediments ranged 6.5-32.9, 0.2-1.2, and 0.1-5.5 ngg(-1) dry wt, respectively. The maximum concentrations were all found near the Haibo River mouth, affected by sewage sludge input from the river. Under the current system in Jiaozhou Bay the organic pollutants were subject to deposit on the east side of the bay and trapped inside the bay. Sewage sludge was an important source of PCBs, PCNs and PBDEs in the bay and exponentially magnified the enrichment of PCBs. On the other hand, the congener profiles of PCBs in sediments outside the bay may signify an atmospheric source of PCBs. Total Concentrations of PCBs, PCNs and PBDEs in mussels were 61.4-88.6, 9.0, and 13.8 ngg(-1)lipid, respectively. Mussels enriched significantly PCBs, PCNs and PBDEs relative to the sediments. The total toxicity equivalent quantities (TEQs) of PCNs in mussels were generally lower than that of PCBs. The fluxes of the total PCBs and their TEQs have been decreased steadily since 1950s. The lower chlorinated/brominated congeners of PCNs and PBDEs may exhibit a greater tendency due to less lipophilic and thus a greater probability of being affected by the current circulation in the bay.