Per- and polyfluoroalkyl substances, or PFAS, are accumulating in dead juvenile seabirds in three locations off the Atlantic Coast, including North Carolina, according to a study published this month in Environmental Science and Technology, raising questions about how the chemicals might be affecting humans.
PFAS refers to a group of nearly 5,000 substances often called “forever chemicals” because they take hundreds of years to break down. They are found in the blood of 99% of Americans, and are linked to reproductive, developmental and immune system impacts in lab animals, according to the EPA.
The study looked for 36 different types of PFAS in liver tissue samples from 31 baby seabirds found dead in the Massachusetts Bay, Rhode Island’s Narragansett Bay and North Carolina’s Cape Fear River Estuary in 2017.
These locations were chosen because they have different exposure risks to PFAS, with the Cape Fear River Estuary being most at risk because it’s 90 miles downstream from the PFAS manufacturer Chemours.
Overall, seabirds from the Cape Fear River Estuary had significantly greater concentrations of PFAS than seabirds in the Massachusetts or Narrangansett Bay. The most abundant type of PFAS found was PFOS, a chemical used in stain repellants like Scotchgard until it was phased out of production in the early 2000s.
“That was not a surprise,” said Anna Robuck, the lead researcher of the study and a doctoral candidate at the University of Rhode Island Graduate School of Oceanography. “PFOS is the abundant compound found in most wildlife, even though we have stopped producing it.”
The study also showed that as levels of some PFAS, like PFOS, increased, the concentration of a type of fat in seabird livers decreased. Previous studies have found connections between PFAS and liver impairments, but this study is the first field-derived evidence of this specific relationship in seabirds.
“Fat stores are so important, you can’t reproduce if you don’t have enough fat, you can’t migrate if you don’t have enough fat,” said Robuck. “We need more research on this relationship.”
In the Cape Fear River Estuary seabirds, three PFAS unique to the Chemours production facility were also found. These PFAS — Nafion byproduct-2, PFO4DA and PFO5DoDA — are known as novel PFAS, and are just a few of over 250 PFAS that have been detected in Chemours’s waste stream.
In some birds, the levels of novel PFAS exceeded the levels of PFOS. Novel PFAS were also found in the livers of seabirds with no known connection to the Chemours facility.
“For us, this says that these novel PFAS are persistent in the environment enough that they can travel a long way,” said Robuck. “That was pretty shocking to find.”
Lindsay Addison, a coastal biologist with Audubon North Carolina who located the NC seabirds for this study, said she’s worried about these findings because a quarter of coastal waterbirds in North Carolina live in the Cape Fear River.
“This could be a big deal in terms of sustaining the populations of all these bird species,” said Addison.
The levels of PFAS found in the Cape Fear River Estuary seabirds were 20 times higher than the levels of PFAS found in the river’s striped bass. This is a result of bioaccumulation, a process that results in higher levels of chemicals in animals higher up on the food chain.
“If you have a chemical that accumulates up the food chain, you’re screwing over the upper-level predators,” said Robuck. “And humans often end up being those upper-level predators.”
Bioaccumulation is particularly a threat to some of the seabirds used in the study, like Brown Pelicans and Terns, because the species can live for a long time.
“Brown Pelicans can live over 10 years and Terns up to 30,” said Addison. “So there’s a lot of time for this stuff to bioaccumulate and affect them.”
The novel PFAS found in the Cape Fear River Estuary seabirds have also been found in the blood of Wilmington, NC, residents. A study published in Environmental Health Perspectives in July found that 24% of the PFAS detected in Wilmington blood samples came from the same three novel PFAS detected in the seabirds. One of these PFAS, Nafion byproduct-2, was found in the blood of 99% of study participants.
The levels of novel PFAS found in the seabird livers exceeded the levels found in these blood samples. Robuck said this raises questions about how these compounds accumulate in human livers, since that has not been studied.
Emily Donovan, co-founder of community group Clean Cape Fear, thinks that more studies looking for PFAS in humans should be initiated.
“This shows that when you start opening and dissecting organs, you start finding collections of these compounds,” said Donovan. “We’ve had blood and urine samples done in our area and we now need to start providing medical monitoring. I’d be curious to see if there is an increase in nonalcoholic fatty liver disease among our region’s overexposed residents.”
Robuck said that looking at the presence of PFAS in seabirds gives a rough idea of what the presence of these chemicals in humans looks like.
“Birds are a good proxy for what we get, as humans, from our environment,” said Robuck. “We use the phrase ‘canary in a coal mine’ for a reason.”