Contaminants in bald eagles of the upper Midwestern U.S.: A framework for prioritizing future research based on in-vitro bioassays. (January 2019)

• Record Type: Journal Article
• Authors: Elliott, Sarah M.; Route, William T.; DeCicco, Laura A.; VanderMeulen, David D.; Corsi, Steven R.; Blackwell, Brett R.
• Is Part Of: Environmental pollution. Volume 244(2019)
• Page Start: 861
• Page End: 870
• Publication Date: 2019-01
• Subjects: Perfluorinated chemicals -- ToxCast -- Plasma -- In-vitro bioactivity; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2018.10.093
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Several organic contaminants (OCs) have been detected in bald eagle ( Haliaeetus leucocephalus) nestling (eaglet) plasma in the upper Midwestern United States. Despite frequent and relatively high concentrations of OCs in eaglets, little is understood about potential biological effects associated with exposure. We screened an existing database of OC concentrations in eaglet plasma collected from the Midwestern United States against bioactivity information from the ToxCast database. ToxCast bioactivity information consists of concentrations expected to elicit responses across a range of biological space (e.g. cellular, developmental, etc.) obtained from a series of high throughput assays. We calculated exposure—activity ratios (EAR) by calculating the ratio of plasma concentrations to concentrations available in ToxCast. Bioactivity data were not available for all detected OCs. Therefore, our analysis provides estimates of potential bioactivity for 19 of the detected OCs in eaglet plasma. Perfluorooctanesulfonic acid (PFOS) EAR values were consistently the highest among all study areas. Maximum EAR values were ≥1 for PFOS, perfluorononanoic acid, and bisphenol A in 99.7, 0.53 and 0.26% of samples, indicating that some plasma concentrations were greater than what may be expected to elicit biological responses. About 125 gene targets, indicative of specific biological pathways, were identified as potentially being affected. Inhibition of several CYP genes, involved in xenobiotic metabolism, were most consistently identified. Other identified biological responses have potential implications for motor coordination, cardiac functions, behavior, and blood circulation. However, it is unclear what these results mean for bald eagles, given that ToxCast data are generated using mammalian-based endpoints. Despite uncertainties and limitations, this method of screening environmental data can be useful for informing future monitoring or research focused on understanding the occurrence and effects of OCs in bald eagles and other similarly-positioned trophic species. Graphical abstract: Image 1 Highlights: Organic contaminants in bald eaglet plasma screened for potential sub-lethal effects. Exposure—activity ratios calculated as plasma concentration/activity concentration. Maximum exposure—activity ratios >1 for PFOS, PFNA, and bisphenol A. Consistently high exposure—activity ratios for CYP and BACE1 genes. Little intra-study area variability, but high inter-study area variability. Abstract : Comparison of organic contaminant concentrations in bald eaglet plasma to bioactivity data from in-vitro bioassays indicates that PFOS, CYP-related endpoints, and sites near urban areas should be prioritized for future monitoring focused on understanding the effects of organic contaminant exposure in bald eagles.