R5 PM Avian Sentinels of Environmental Contamination
Thursday, 17 November 2005: 1:50 PM - 5:30 PM in 321-323

(CES-1117-818613) The effect of PCBs, PBDEs, and their hydroxylated metabolites on thyroid hormone and vitamin A levels in bald eagles.

Cesh, L.¹, Williams, T.¹, Garcelon, D.², Letcher, R.³, Elliott, J.⁴, ¹ Simon Fraser University, Burnaby, British Columbia, Canada² Institute for Wildlife Studies, Arcata, California, USA³ Canadian Wildlife Service, Ottawa, Ontario, Canada⁴ Canadian Wildlife Service, Delta, British Columbia, Canada

ABSTRACT- Recent studies have shown polybrominated diphenyl ethers (PBDEs) to be notable chemicals of concern. PBDEs are widely used flame retardants and appear to be increasing exponentially in the environment. PBDEs have a similar molecular structure to polychlorinated dibenzo-p-dioxins (PCDDs), furans (PCDFs), and biphenyls (PCBs). Since these chemicals are known to be toxic, persistent, and bioaccumulative there is concern that PBDEs will have similar detrimental effects on wildlife and humans. Studies have shown that PCBs and PBDEs can impair the metabolism of vitamin A and decrease circulating thyroid hormones, which are required for proper growth, development, cell differentiation, immunology, vision, and reproduction. The objectives of this study are to monitor the levels of PCBs and PBDEs in British Columbia and southern California and to investigate potential effects of PCBs, PBDEs, and their hydroxylated metabolites on vitamin A and thyroid hormones (TT3 and TT4) in bald eagles. Blood samples were collected from nestling at 6 different sites; 5 in British Columbia and 1 in southern California. The results show a significant negative correlation between PCBs and TT4 levels in the plasma, but this relationship was not seen for TT3 or vitamin A. There was no significant relationship between PBDEs and TT4, TT3, or vitamin A. The results for the hydoxylated metabolites are not yet available, but will be discussed at the conference

Key words: PBDEs, PCBs, bald eagle, thyroid hormone