Using a Multi-Tracer Approach to Examine Perfluoroalkyl Substance Sources and Dietary Exposure Pathways in Pacific...

Area of Science:

• Environmental Science
• Ecotoxicology
• Wildlife Biology

Background:

• Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants found globally.
• Avian apex predators like bald eagles are susceptible to PFAS bioaccumulation.
• Understanding species-specific PFAS bioaccumulation and dietary links is crucial for conservation.

Purpose of the Study:

• To assess PFAS exposure in bald eagle nestlings along the Pacific coast of British Columbia.
• To investigate the relationships between PFAS profiles, diet, habitat use, and biological factors.
• To identify dietary sources contributing to PFAS burdens in this apex predator.

Main Methods:

• Blood samples from 89 bald eagle nestlings were analyzed for 17 PFAS.
• Stable isotope analyses (δ15N, δ13C, δ34S) were used to determine trophic position and habitat use.
• Fatty acid profiling differentiated aquatic from terrestrial prey contributions to the diet.

Main Results:

• PFAS exposure varied significantly by region and nestling age.
• Perfluorooctanesulfonic acid (PFOS) was the dominant PFAS detected.
• Certain PFAS (PFUdA, PFTrDA) correlated with marine diet indicators, while others (PFOS, PFHxS) suggested terrestrial food web biomagnification.

Conclusions:

• This study provides the first comprehensive PFAS exposure data for Pacific bald eagles.
• Dietary tracers revealed complex pathways influencing PFAS accumulation in this apex predator.
• Findings highlight the importance of integrated approaches to understand contaminant dynamics in wildlife.