Words by Adele Morris
Photos and Graphics by Anders Ljung
Tracking forever chemicals: NC researchers lead the way on PFAS health risks
When Wilmington residents learned in 2017 that their drinking water was tainted with a little-known chemical called GenX, it sparked public outrage—and extensive scientific research that’s still unfolding today.
GenX is just one of more than 14,000 chemicals known as per- and polyfluoroalkyl substances, or PFAS. PFAS, also referred to as “forever chemicals,” are manmade compounds that have been used in product manufacturing since the 1940s. They are known for their persistence in the environment and their ability to accumulate in the human body.
PFAS are associated with a variety of health risks, including cancer, infertility and reduced vaccine effectiveness. Several North Carolina scientists have taken on research projects investigating exposure, toxicology, and the health effects of these chemicals.
Exposure studies
Heather Stapleton, a professor of exposure science and environmental chemistry at the Nicholas School of the Environment at Duke University, looks at how PFAS exposure contributes to cancer risk among firefighters. She serves as the director of the North Carolina Firefighter Cancer Cohort Study (N.C. FFCCS).
“There’s ample and sufficient evidence to suggest that cancer rates, incidence rates, in firefighters are higher than the general population for several types of cancers,” she said. “So there’s a need to really understand what’s driving this and what can be done to mitigate the exposure stressors and thus mitigate the cancer risk.”
The N.C. FFCCS launched around March 2024 and is affiliated with the National Fire Fighter Cancer Cohort Study, which began in 2016.
Stapleton said the overarching goal of the national study is to follow 10,000 firefighters for 30 years, recontacting them every two years to collect updated medical histories and additional blood and urine samples. This long-term effort will assess how exposure and stressors relate to cancer risk.
So far, the N.C. FFCCS has recruited approximately 350 firefighters across the state, with the goal of enrolling 1,000.
Stapleton said that PFAS levels in firefighters vary by region, reflecting differences in local drinking water contamination. She noted that PFAS levels in firefighters mirrored those in other North Carolina residents participating in an exposure study led by Dr. Jane Hoppin, a professor in the department of biological sciences at North Carolina State University.
That study, known as the GenX Exposure Study, focuses on measuring GenX and other PFAS in residents living near the Cape Fear River Basin. The study was funded by the National Institute of Environmental Health Sciences in 2017 after the publication of a viral StarNews article and began with the blood sampling of over 300 people in the Wilmington area.
“If we compare firefighters in Wilmington to residents of Wilmington that are in Dr. Hoppin’s study, those levels look the same, with the one exception,” Stapleton said. “There’s one PFAS that goes by the acronym PFHxS, which does seem to be higher, and that is a PFAS that has been identified in the fire suppression system called AFFF, or aqueous film-forming foam.”
AFFF is a type of foam that firefighters use to fight fires started by flammable liquids.
But as the GenX Exposure Study has shown, heightened PFAS exposure is not limited to firefighters.
Hoppin said her team has identified three new PFAS in the blood of nearly every Wilmington participant. These new PFAS were linked to the Fayetteville Works plant operated by the chemical manufacturing company Chemours. In 2019, Chemours signed a consent order to reduce its PFAS pollution from air emissions by 99.99 percent and from a large on-site stream by at least 99 percent.
In 2020, Hoppin received a grant from the N.C. State University Superfund Center to create a cohort of over 1,000 North Carolina residents to follow long-term and investigate changes in exposure and health effects. Hoppin has enrolled residents in the Wilmington, Fayetteville and Pittsboro areas.
So far, many of the cohort’s members have participated in two blood samplings.
“We were able to see that the levels of PFAS in people’s blood were coming down during a time when communities have made big efforts to reduce PFAS in drinking water,” Hoppin said.
Toxicology studies
Beyond tracking exposure, some scientists are studying how PFAS affect the human body at a cellular level.
Jamie DeWitt, a professor in environmental and molecular toxicology and director of the Pacific Northwest Translational Center for Environmental Health Research at Oregon State University, studies how PFAS affect vaccine effectiveness.
In 2013, as a professor in the department of pharmacology and toxicology at East Carolina University, DeWitt began studying the harmful effects of the GenX chemical.
She discovered that GenX could suppress the immune system. Her research now uses rodent and cell models to explore how PFAS alter immune responses.
“Studies of people who have been exposed to PFAS and studies of experimental animals that have been intentionally exposed to PFAS show that they have a reduction in their ability to make antibodies against vaccines,” she said. “So we can study this process in rodents and it occurs the same way in people.”
DeWitt explained that in both humans and rodents, vaccination prompts B cells, a type of white blood cell, to produce specific antibodies. This response is particularly sensitive to PFAS.
Macon Carroll, a third-year PhD student studying under DeWitt, said she studies the B cells in mouse spleens. These cells play a key role in immunity by producing antibodies that fight off pathogens.
Carroll investigates whether PFAS alter the balance between immature and mature B cells, using a device called a flow cytometer to measure the number and types of B cells present.
“If those [B cells] are being affected by PFAS, then that’s going to affect your ability when it comes to protecting yourself over getting sick or your vaccination status,” she said. “So what the work that I’ve done really looks at is, ‘Are these cells that do help protect you and help that vaccine function, are they functioning properly, and are they getting to the state where they can, in fact, help you?’”
Tracey Woodlief, a research assistant professor in the Department of Pharmacology and Toxicology at ECU, is also researching the impact of PFAS on the immune system, focusing specifically on molecular mechanisms — the specific biological processes occurring within cells.
When new PFAS are detected in water or blood, she obtains a sample and tests it with experimental models. She has tested around 15 compounds individually and conducted some combination studies.
Woodlief said her goal is to identify the molecular mechanisms and test compounds more efficiently.
She found that newer PFAS behave similarly to legacy PFAS, affecting B cell numbers and the T-cell-dependent antibody response — a process in which B cells need the help of another type of white blood cell called a T-cell to produce effective antibodies.
“Even though these new and novel [PFAS] compounds may be shorter and potentially have a higher elimination from the body, they have similar clinical anchors and impacts on the immune system overall,” Woodlief said.
Future direction
Woodlief, Hoppin and DeWitt all emphasized the need for more research into PFAS’ molecular mechanisms to better understand how PFAS can influence the development of disease and how the body’s immune system responds.
But Stapleton said she wants to research how firefighters’ combined exposure to PFAS, metals, combustion byproducts and flame retardants influence hormone levels and risks for other diseases.
She also hopes to expand PFAS exposure studies to include other occupations — like hair stylists, nail technicians, construction workers and painters — using personal monitors to measure people’s exposure.
These monitors are silicone wristbands that collect chemicals from the environment. Participants wear them for five to seven days before sending them to the lab for analysis.
“We’ve shown in our lab that measurements of these chemicals on the bands are pretty strongly, significantly correlated to what gets in our body, with the exception of your exposures through the diet,” she said.
Stapleton emphasized the importance of studying how exposure varies by lifestyle, environment, furniture, and even personal care products.
Funding challenges
Despite growing awareness, researchers face funding challenges.
Stapleton said she works on projects funded by the Federal Emergency Management Agency (FEMA) and the National Institutes of Health (NIH), in collaboration with researchers at the National Institute for Occupational Safety and Health (NIOSH). But she said recent NIOSH layoffs and potential program cuts are concerning.
“Those folks, some have been let go, and some have received a notice that they are about to be terminated in June,” she said. “So it’s upsetting to the program, to the group to trying to implement this research.”
Stapleton noted that NIOSH has the only facility in the country capable of certifying respiratory equipment for firefighters, and it was shut down. She said it is unclear how future respiratory systems will be certified for use in firefighting departments moving forward.
Meanwhile, DeWitt, the professor at Oregon State, said she is concerned that the Trump administration’s cuts to federal funding could reduce research into newly discovered PFAS.
“There’s still a lot of PFAS out there that haven’t been studied,” she said. “And I don’t know if we have really great strategies for trying to prioritize those. Now there are, or were, great strategies being developed at the U.S. EPA, but with that agency potentially being cut, those types of approaches are going to be stalled or perhaps eliminated.”
She added that reduced funding could limit the data needed to inform public health policy and hinder access to preventive care.
Hoppin, the principal investigator of the GenX Exposure Study, said that given the current funding climate, she has shifted her focus to analyzing existing data rather than collecting more blood samples.
“It costs about $1,000 a person for when we collect blood from people for all the things that we do, and so we have a thousand people in our cohort,” she said. “So that’s a million dollars. And it’s not a good time to be asking for a million-dollar-a-year grant. So we’re going to work with the data that we have.”
While much of her work revolves around understanding exposure and the potential health effects linked to PFAS, Hoppin said it also includes community engagement and sharing individual and community-level results when available.
But DeWitt noted that beyond funding, PFAS research simply takes time.
“One of the questions that comes up in general is that, well, ‘Can we prove that exposure causes these diseases?’ And one of my answers to that is that it takes time to prove causation,” she said. “Remember, PFAS science really was in its infancy, only about 20-some years ago, and so we’re growing the data. It takes time to really link exposure with effects, especially when exposures are environmental.”
