Congener specific distributions of polybrominated diphenyl ethers (PBDEs) in sediment and mussel (Mytilus edulis) of the Bo Sea, China

Congener specific distributions of polybrominated diphenyl ethers (PBDEs) were investigated in sediment and mussel (Mytilus edulis) collected from the coast of Bo Sea, China. The median values of BDE-209 and ΣPBDEs (including BDE-17, -28, -47, -66, -71, -85, -99, -100, -138, -153, -154, -183 and -190) were 2.29 and 0.16 ng g−1 dry weight in sediment, and 2.43 and 0.68 ng g−1 dry weight in mussel, respectively. BDE-209 was the predominant congener (61–99% in mussel and 75–99% in sediment except for one sample with 17%). Different congener patterns (excluding BDE-209) were observed between sediment and mussel, which were attributed to individual congener’s bioaccumulation potential and/or the ability to metabolize. The four most abundant congeners were BDE-47 (40.3%), -99 (22.5%), -71 (8.9%) and -28 (5.8%) in sediment, and -47 (36.4%), -28 (14.5%), -154 (8.6%) and -71 (8.6%) in mussel, respectively. The ratios of BDE-47/BDE-99 and BDE-100/BDE-99 in sediment were lower than those in mussel, indicating higher transformation and uptake rate of BDE-99 in mussel. The biota-sediment accumulation factor (BSAF) of individual PBDE congeners declined with the increase of their logarithm of octanol–water partition coefficients (log KOW) except for BDE-154, indicating congeners with higher log KOW were more likely to retain in sediment. These can be explained with a high affinity of these compounds for carbonaceous geosorbents, and molecular steric hindrance that limits large, very hydrophobic organic compounds from penetrating the cellular membranes.