Effect of Municipal Sewage Treatment Plant Effluent on Bioaccumulation of Polychlorinated Biphenyls and Polybrominated Diphenyl Ethers in the Recipient Water

Water, sediment, and aquatic species including plankton, fish, and turtles were collected from a small lake in Beijing, which receives effluent discharged from a large sewage treatment plant (STP). The samples were examined to investigate polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) releases from a STP and their distributions in the lake. The accumulations of ∑₁₂PBDEs and BDE-209 in the sediment were 62.3 and 1150 ng/cm², respectively, while that of ∑PCBs was 99.3 ng/cm². BDE-209 was detected in more than 50% of the aquatic species. A strong linear correlation (R² = 0.92) was found between ∑₁₂PBDEs and ∑PCBs levels in aquatic species but not in sediments. The different PBDE congener profiles in sediments and biota samples suggest metabolic debromination in the sampled fish. Bioaccumulations of PBDEs and PCBs were found in aquatic species. The logarithm bioaccumulation factor (BAF) decreases with the number of bromines in PBDEs molecules, while the log BAF versus the number of chlorines in PCBs appears to be parabolic. Biomagnifications of these compounds were not obvious in the food web by analysis of the relationship between ∑₁₂PBDEs or ∑PCBs levels and the trophic level of aquatic biota species.