Polybrominated diphenyl ethers and its methoxylated analogues in biota and sediment samples from two freshwater lakes in Yangtze River delta

In the present study, sediments and biotas from two freshwater lakes in Yangze delta area were collected and analyzed for polybrominated diphenyl ethers (PBDEs) and methoxylated PBDEs (MeO–PBDEs). The concentrations of PBDEs in sediments and biotas ranged from 0.41 to 5.8 ng/g dry weight and from 4.6 to 100 ng/g lipid weight, respectively, while those of MeO–PBDEs were much lower (sediment: <LOQ-0.014 ng/g dry weight, biota: <LOQ-2.1 ng/g lipid weight). The levels of both brominated substances in sediments and biotas were in the moderate to low range compared with other studies. Different BDE congeners were found between two lakes probably due to the different exogenous sources and metabolic stages. Similar occurrence of higher brominated congeners (e.g., BDE-209) in sediments and biotas indicated sediments as a possible source of PBDEs for biotas. The different contribution of lower and higher brominated congeners between sediments and biotas may be due to the combined effect of biotransformation and bioavailability.