Bald eagles as bio-sentinels: Monitoring and fingerprinting PFAS contamination

Area of Science:

• Environmental Science
• Ecotoxicology
• Wildlife Biology

Background:

• Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants of concern.
• Bald eagles (Haliaeetus leucocephalus) occupy a high trophic level, making them sensitive indicators of ecosystem health.
• Understanding regional PFAS contamination is crucial for effective environmental management in the Great Lakes.

Purpose of the Study:

• To assess bald eagle nestlings as sentinel species for PFAS fingerprinting.
• To quantify and map regional PFAS contamination in Wisconsin, Lake Superior, and Lake Michigan.
• To evaluate the utility of PFAS compositional profiles for source attribution.

Main Methods:

• Plasma samples were collected from 115 bald eagle nestlings between 2023-2025.
• PFAS concentrations and compositional profiles were analyzed across seven distinct regions.
• Statistical analyses, including principal component analysis, were used to identify contamination patterns.

Main Results:

• Total PFAS levels varied significantly by region, with the highest concentrations found in the Middle Wisconsin River and Apostle Islands.
• Distinct regional PFAS fingerprints were observed, including elevated PFOS in the Middle Wisconsin River and legacy compounds in the Apostle Islands.
• Site-specific contamination patterns suggested a mix of point-source and diffuse PFAS inputs.

Conclusions:

• Bald eagle nestlings are valuable biomonitors for spatially explicit PFAS assessment.
• PFAS fingerprinting in bald eagles aids in identifying contamination sources and informing risk assessments.
• This approach enhances our understanding of PFAS distribution in the Great Lakes ecosystem.