Patterns of Bioaccumulation of Polybrominated Diphenyl Ether and Polychlorinated Biphenyl Congeners in Marine Mussels

Marine mussels (Modiolus modiolus) and sediment from 14 stations near a municipal outfall and three reference locations were analyzed for polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) to evaluate and compare patterns of bioaccumulation of individual congeners between these two groups of chemicals. Of the 47 PBDEs and 209 PCBs analyzed, 34 PBDE and 153 PCB congeners or coeluting groups of congeners were detected in one or more matrices. The predominant PBDE congeners were BDEs 47, 99, 100, and 209, accounting for 80-90% of the total PBDEs in all matrices. PCBs and PBDEs exhibited a parabolic relationship of the biota-sediment accumulation factor (BSAF) versus the log octanol-water partition coefficient (K(OW)). Below K(OW) 10(5.5), BSAFs ranged between 1 and 3, reflecting approximate equilibrium between mussels and sediment for these relatively water soluble congeners. BSAFs increased with increasing K(OW) to maximum values of approximately 30-100 for congeners with K(OW) similar to 10(7) and then declined at higher K(OW) to a value of approximately 1 for BDE 209. BSAFs for PBDEs were generally 2- to 3-fold higher than those for PCBs of a similar K(OW). The calculated BSAFs for PBDE congeners indicate that PBDEs have a pattern of bioaccumulative behavior in mussels similar to that of the PCBs, and that some PBDE congeners may be more bioaccumulative in mussels than PCBs.