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(P045) Testing Biomarkers for Use in Bald Eagle Biosentinel Projects.
Roe, Amy*,1, Croisant, Emma2, Grasman, Keith2, Sikarskie, James3, Bowerman, William1, 1 Clemson University, Pendleton, SC, USA2 Wright State University, Dayton, OH, USA3 Michigan State University, East Lansing, MI, USA
ABSTRACT- The bald eagle (Haliaeetus leucocephalus) has been chosen as the primary biosentinel species to monitor bioaccumulative compounds of concern in Michigan. Blood and feathers from nestling eagles are collected from 20% of the watersheds in the state each year for analysis of organochlorine pesticides, PCBs, and mercury. In order to expand this program, we are determining which biomarkers are potentially useful for observing subtle effects of environmental toxicants on the health of the nestling eagles. Potential biomarkers include circulating levels of hormones and fat-soluble vitamins, blood-borne parasites, immune function tests, and fecal coliform patterns. Immune function and fecal coliform patterns are reported elsewhere. Field samples were collected from nestling bald eagles. A controlled laboratory study exposing chickens to PCBs was conducted. Fertilized, leghorn chicken eggs were unexposed or injected with 0, 0.100, 0.175, 0.250 or 0.325 ng/g of PCB 126 in sunflower oil into the air cell. Results to date have shown that eagles from more contaminated locations (i.e., Great Lakes coastal sites) are not more susceptible to blood-borne parasites. However, there was a relationship between location and corticosterone induction after an ACTH challenge. Eagles from Great Lakes coastal territories produced less corticosterone after ACTH challenge than those from the less contaminanted interior. No clear relationships have been established between location and thyroid hormone levels. For chickens, no relationships were observed between concentration of PCB 126 in a single in ovo exposure and thyroid hormone or vitamin A levels. Based on the results of this chicken experiment, neither thyroid hormone level nor vitamin A level appear to be useful biomarkers of PCB toxicity. However, this was an in ovo exposure and endpoints were not measured until 5 weeks post-hatch.
Key words: bald eagle, corticosterone, vitamin A, biomarkers
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