PFAS from 2024 spill are showing up in Harpswell’s birds
Wildlife near Harpswell is carrying chemical fingerprints from a firefighting foam spill that occurred at the former Brunswick Naval Air Station last summer.
Scientists from Portland's Biodiversity Research Institute discovered elevated PFAS levels in eider ducks and bald eagles nesting in and around Harpswell Cove. The contamination traces back to August 2024, when 1,450 gallons of aqueous film-forming foam concentrate mixed with 50,000 gallons of water and entered streams draining into the cove.
The researchers found themselves in a rare position. Having monitored eiders in Casco Bay for mercury since roughly 2015, they possessed pre-spill baseline data. "You only study a site after the spill happens," noted Christine Gardner, director of the institute's toxicology laboratory.
After waiting until May 2025 to safely sample nesting birds, the team documented PFAS concentrations four to five times higher in avians within five miles of Brunswick Landing than in those tested 40 miles away. Bald eagles showed average PFAS levels roughly four times higher than eiders, with the 2025 Harpswell eagles registering higher readings than any other coastal eagles the institute has sampled.
Miller attributed the disparity to diet. Eagles sit atop the food chain, concentrating pollutants from prey that includes eiders, while eiders consume crabs, mussels, and snails. The team identified firefighting-foam-specific chemicals and mapped highest concentrations to areas nearest the spill site.
The work continues through a partnership with Bowdoin College's Schiller Coastal Studies Center on Orr's Island. Student Olivia Ho has helped collect water, sediment, and shellfish samples while tracking GPS-tagged eiders between Harpswell and Muscongus Bay.
Despite finding clear links to the spill, scientists caution that PFAS health effects on wildlife remain poorly understood. Miller acknowledged the frustration of incomplete answers but expressed hope that documenting this local event will expand broader knowledge. "It's going to take a long time to learn a lot about this," he said.
