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Contaminants in bald eagles of the upper Midwestern U.S.: A framework for prioritizing future research based on in-vitro bioassays
Citation:
Elliott, S., W. Route, L. DeCicco, D. VanderMeulen, S. Corsi, AND B. Blackwell. Contaminants in bald eagles of the upper Midwestern U.S.: A framework for prioritizing future research based on in-vitro bioassays. ENVIRONMENTAL POLLUTION. Elsevier Science Ltd, New York, NY, 244:861-870, (2019). https://doi.org/10.1016/j.envpol.2018.10.093
Impact/Purpose:
Various organic contaminants are present in aquatic environments with the potential to bioaccumulate to higher trophic levels. Because of their mainly piscivorous diet, bald eagles (Haliaeetus leucocephalus) can provide information regarding the bioaccumulation of contaminants from aquatic environments to higher trophic levels. To prioritize contaminants detected in the plasma of eaglets from the Upper Midwest, exposure activity ratios (EAR) were determined by calculating the ratio of observed plasma concentrations to concentrations expected to elicit biological responses from the high throughput screening program ToxCast. EAR values were =1 for PFOS, PFNA, and bisphenol A in 99.7, 0.53 and 0.26% of samples, indicating plasma concentrations were higher than what would be expected to elicit biological responses. About 125 genes were identified as potentially being affected by concentrations of the detected contaminants in eaglet plasma. Use of high throughput screening data can guide future monitoring or research efforts focused on understanding the occurrence and effects of organic contaminants in bald eagles and other similarly-positioned trophic species.
Description:
Various organic contaminants (OCs) are present in aquatic environments with the potential to bioaccumulate to higher trophic levels. Because of their mainly piscivorous diet, bald eagles (Haliaeetus leucocephalus) can provide information regarding the bioaccumulation of OCs from aquatic environments to higher trophic levels. Although several OCs such as polychlorinated biphenyls (PCBs), perfluorinated chemicals (PFCs), and polybrominated diphenyl ethers (PBDEs) have been detected in bald eagle nestling (eaglet) plasma, few studies have evaluated the potential sub-lethal effects of these contaminants. We screened an existing database of OC concentrations in eaglet plasma collected from six study areas within and near national parks in the midwestern United States by calculating the ratio of plasma concentrations to concentrations expected to elicit biological responses from the high throughput screening program ToxCast. These ratios, called exposure activity ratios (EAR), provide estimates of potential bioactivity for 19 of the OCs detected in eaglet plasma, including seven PFCs, two phthalates, two PBDEs, two antimicrobials, two parabens, PCB187, bisphenol A, octylphenol, and dieldrin. Perfluorooctanesulfonic acid (PFOS) EAR values were consistently the highest for all chemicals among the six study areas. EAR values were =1 for PFOS, PFNA, and bisphenol A in 99.7, 0.53 and 0.26% of samples, indicating plasma concentrations were higher than what would be expected to elicit biological responses. About 125 genes were identified as potentially being affected by concentrations of the detected OCs in eaglet plasma. Several CYP genes, involved in xenobiotic metabolism, were most consistently identified. Other identified genes may affect biological processes involved in motor coordination, cardiac functions, behavior, and blood circulation. Variability among sites within the same vicinity was minimal; however, wide variability was evident among spatially disconnected sites. Use of high throughput screening data can guide future monitoring or research efforts focused on understanding the occurrence and effects of organic contaminants in bald eagles and other similarly-positioned trophic species.
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DOI: Contaminants in bald eagles of the upper Midwestern U.S.: A framework for prioritizing future research based on in-vitro bioassays