Specific accumulation of polybrominated diphenyl ethers including deca-BDE in tissues of harbor seals from the northwest Atlantic

To examine tissue-specific accumulation of PBDEs, this study analyzed tri- through deca-BDEs in liver samples of harbor seals (n=56) from the northwest Atlantic region, and compared concentrations and patterns with those detected previously in blubber. Hepatic concentrations of ΣPBDEs ranged from 35 to 19547 ng/g lw (overall mean 2671 ng/g lw) and were similar to the concentrations in blubber (overall mean 2403 ng/g lw). Hepatic ΣPBDE concentrations were highest in the male pups (mean 4397 ng/g lw); their levels were significantly higher than those in the female pups. Tissue distribution of PBDEs differed markedly among male and female pups, suggesting possible gender differences in metabolism and elimination/retention of PBDEs among young seals. Congener profiles were dominated by BDE-47, indicating exposure to penta-BDE mixtures. Congener dominance in the pups was in the order: BDE-47>-99>-100>-153>-154>-155>, whereas hexa-BDEs surpassed penta-BDEs in the adult male profiles. Hepta- and octa-BDEs and BDE-209 were detected in seal liver, suggesting recent exposure to the octa- and deca-BDE formulations and/or BDE-209 debromination processes. Although detection frequency was low, BDE-209 levels in liver samples with detection (range:10 to 40 ng/g lw) were up to five times higher than those detected in blubber, implying that liver may be a preferential tissue for BDE-209 accumulation in harbor seals. Moreover, hepatic concentrations of BDE-209 in the seals were up to ten times higher than those reported in fishes that are harbor seal prey. These results suggest that BDE-209 can biomagnify in seal tissues and is subject to placental and/or lactational transfer, possibly placing pups at risk for adverse developmental effects