An osprey plucks an alewife from the waters of the Sebasticook River in Benton as the alewives make their annual run upriver. Michael G. Seamans/Staff Photographer

Equipped with a floating mesh net and black-and-white decoys, wildlife biologist Micah Miller jumped on a boat Monday to begin hunting for harmful forever chemicals in the bloodstreams of common eiders, North America’s largest native duck.

Over the last three years, Miller has found high levels of the chemicals in blood drawn from eagles, loons and ospreys, some of Maine’s best known fish-eating birds. Now Miller is expanding his research to include the island-nesting species that prefers to feed on mussels.

It took eight hours for Miller and a team from the Biodiversity Research Institute in Portland to catch seven eiders in the net about 20 yards from a small, uninhabited Midcoast island. They might have gotten more samples if the weather wasn’t so calm.

“Rough water means the birds can’t see the net and that’s good for us,” he said. “Too nice, like it was (Monday), they’ll spot the net and stay away.”

Leigh LaMartina of the Biodviersity Research Institute helps collect data about common eiders nesting on a small island in Casco Bay last week. Photo courtesy of the Biodiversity Research Institute

The researchers band and weigh each bird and then draw a blood sample, which is sent to a lab that will provide him with a breakdown of the forever chemicals in each duck’s bloodstream. But he’ll have to wait – the results won’t be available until winter.

That’s OK because Miller will be busy. In late May, after he has collected enough eider samples, he will start climbing trees and rocky cliffs across Maine to test baby eagles. Miller will then don his waders in June and July to sample loon hatchlings and adults in their secluded lakeside nests.


The research will help Miller and others better understand how perfluoroalkyl and polyfluoroalkyl substances, or PFAS, move through our environment: from the factory, sewer plant or sludge-spread farm fields to ponds, lakes and rivers to fish, birds, and mammals.

The birds that Miller and his team are sampling serve as a proxy for another fish-eating species: people. We eat the same trout and mussels they do, although not in the same proportions. The amount of PFAS found in these birds tells Miller a lot about the environmental exposure facing us all.

F Biodiversity Research Institute biologist Chris Persico collects samples from a juvenile bald eagle nesting at the top of a tall tree in northern Maine last May. Photo courtesy of the Biodiversity Research Institute

Even trace amounts of some PFAS can be dangerous to humans, with exposure to high levels of certain PFAS linked to decreased fertility and increased high blood pressure in pregnant women, developmental delays in children and low birth weight, increased risk of some cancers and weakened immune systems.

Very little is known about how PFAS exposure might impact wildlife health, but some scientists predict wildlife will be affected in many of the same ways that humans are. Most wildlife PFAS research that is underway has focused on whether a species can absorb PFAS and pass it on to humans if we eat them.

The chemicals used to make many common household and industrial products resistant to heat, water and grease are almost everywhere: in animals from pandas to polar bears, in the rain, even in our blood. They eventually wind up in our public water supply and many of our ponds, lakes, rivers and oceans.

Once in the water, some of the PFAS are absorbed by fish, which are then eaten by birds, mammals and people. Because the bond between the fluorine-carbon bond is so strong, the amount of at least some of these chemicals will build up as you move up the food chain.


A review of 200 peer-reviewed wildlife studies found forever chemicals in over 600 species across the globe, according to Environmental Working Group, an advocacy group that supports tighter regulation of the chemicals. From Siberian tigers in China to Norwegian worms to Maine harbor seals.  

Two baby loons keep close to a parent on Long Pond in Belgrade. Staff photo /Jeff Pouland

Fish-eating birds function as canaries in the coal mine for other toxins, too, like mercury. They play this role well because they perch at the top of the aquatic food chain, they can be easily tracked because they return to the same nest site every year, and they attract enough interest to secure long-term funding.

Preliminary results from tests of 85 loons and 77 eagles, as well as a small batch of Maine ospreys, found forever chemicals in every sample, including some alarmingly high concentrations. The highest levels of PFAS were found in eagles and loons nesting near Lovejoy Pond in Albion.

Blood samples from Lovejoy Pond topped 500 parts per billion, or ppb, of perfluorooctane sulfonic acid, or PFOS, a well-studied forever chemical that 3M once manufactured for use in firefighting foam, paper and leather coatings and aerosol mists. 3M agreed to phase out production of PFOS in 2000.

Miller has gotten similar results from Sebago and Little Sebago lakes, but not consistently. 

PFOS is also the most common of the 40 forever chemicals found in freshwater fish in Maine. It is what Maine uses as a chemical marker to set consumption thresholds for fish, milk and beef as well as forage grass for dairy cows. It considers six forever chemicals, including PFOS, when assessing drinking water.


The average American has just over 4 ppb of PFOS in their blood. Maine advises against consuming water with more than 20 parts per trillion of six PFAS, milk with 210 ppt of PFOS, or beef with more than 3.4 ppb of PFOS, and advises limiting the consumption of fish with 3.5 ppb of PFOS, and not eating a fish that tops 60 ppb, 

A bald eagle carries an alewife back to the nest on the Sebasticook Stream in Benton. Staff Photo/Michael G. Seamans

Among loons and eagles, adults generally have higher PFAS levels in their blood. 

The Biodiversity Research Institute wants to expand its research to map out the exact path that PFAS follows through the aquatic food web and learn about the health impact on birds. The Environmental Working Group review of global PFAS wildlife research found only a dozen studies that focused on animal health impacts.

But David Andrews, a senior EWG scientist who worked on the review, believes early findings suggest that wildlife will suffer similar health problems as humans, a finding that could help free up the funding to grow that body of research.

He points to initial findings across a range of species: PFAS exposure is spurring steroid growth in polar bear brains and causing reproductive failures, weakening immune response in North Carolina alligators until infected wounds can’t heal, and causing Michigan crayfish and bluegills to forage and swim slower.

In Maine, the research on PFAS in wildlife is still in the early stages, focusing on which ones accumulate in which species, and in what organs, with the most ambitious ones trying to work backward from their target species to determine the primary source of the contamination – water, soil or diet.


The University of Maine’s Chatfield Lab is starting to investigate PFAS build up in wood turtles, a species experiencing a widespread decline in the eastern U.S. Wood turtles overwinter fully submerged in Maine’s small to midsized streams, including some with high concentrations of forever chemicals.

The Wildlife Disease Genetics Lab at UMaine is about to kick off a study of forever chemical exposure in wild game, including wild turkeys, deer, waterfowl and moose, to examine how it impacts the fitness of Maine’s wild game.

Dustin Meattey of the Biodiversity Research Institute helps band a common eider in Casco Bay last week. Photo courtesy of the Biodiversity Research Institute

Maine is already on the front lines of PFAS legislation, regulation and research.

In 2022, after a string of farms connected to the state’s decades-old sludge spreading program shut down because of PFAS contamination, Maine became the first state to ban sludge recycling and PFAS in nonessential products and the first to create an emergency relief fund for impacted farmers.

Maine’s PFAS response has mostly focused on the people who live or work near farms that use sludge-based fertilizer, factories that use PFAS in their industrial processes, and the airports or military bases where firefighting foam with PFAS is used to quickly suppress high-heat chemical fires.

The state has compiled a list of more than 1,100 sites where state records indicate PFAS contamination may exist. It is about halfway through a multi-year investigation of these sites, and has so far found 73 farms that exceed safe water or soil levels and defunct landfills that have tainted 51 drinking wells.

For Dianne Kopec, a faculty research fellow at UMaine’s Mitchell Center for Sustainability Solutions who is working on both UMaine wildlife studies, expanding PFAS research beyond humans is past due.

“We can’t forget that we share this planet,” Kopec said. “Humans made PFAS, and if we can make it, we can clean it up. It won’t be easy, but it’s a problem that we must fix.”

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