Blood concentrations of some persistent organohalogens in free-ranging spotted seals (Phoca largha) from Bristol Bay, Alaska.

In recent years, the relatively high levels of organochlorine contaminants and increasing levels of brominated flame retardants found in tissues of marine mammals have raised concerns that exposure to these marine pollutants may compromise individual health. In this pilot study, levels of 11 polychlorinated biphenyls, 3 polybrominated diphenyl ethers, and the DDT metabolite p,p'-diphenyldichloroethylene were analyzed in whole blood of 7 free-ranging spotted seals (Phoca largha) from Bristol Bay, Alaska, sampled during 2000 and 2001. Blood concentrations of analytes were generally low (<1 ppb wet weight). Open-ocean foraging and feeding on a lower trophic level may contribute to the relatively lower levels of organohalogens found in this species as compared to the closely related harbor seal, Phoca vitulina, occurring in Bristol Bay.