A North Carolina-based research study on exposure to GenX and related chemicals among people living in the Cape Fear River Basin is analyzing new blood samples from four communities with water supplies heavily contaminated with PFAS, including Fayetteville, Pittsboro, New Hanover County and Brunswick County.
Meanwhile, international experts convened in November by the World Health Organization have labeled two legacy types of PFAS — PFOA and PFOS — as carcinogenic and possibly carcinogenic to humans, respectively.
PFAS are a class of toxic and pervasive chemicals colloquially referred to as forever chemicals for their inability to naturally break down in the environment and human body. These chemicals have been used in manufacturing since the 1940s and are found almost everywhere today. They are especially prevalent locally because Chemours and its predecessor, DuPont, dumped chemical waste into the Cape Fear River for decades.
Here’s a breakdown of the latest research on PFAS:
GenX Exposure study
The GenX Exposure Study began in November 2017 with researchers from N.C. State who sought to measure GenX and other PFAS chemical exposure in people living in or near the Cape Fear River Basin, with the goal of assessing exposure levels and potential health effects.
Dr. Jane Hoppin is an environmental epidemiologist and the study’s principal investigator.
“Our overall focus is we want to understand what's happening throughout the Cape Fear river basin and also look at how the exposures differ in the groundwater community compared to people drinking surface water,” Hoppin told CityView.
In 2019, Hoppin’s team took samples from residents in the Fayetteville area surrounding the Fayetteville Works plant, including residents in Cumberland, Bladen and Robeson counties. By July 2021, the researchers had taken samples from about 300 people in the Fayetteville community. Those participants, Hoppin said, granted researchers the opportunity to follow them for up to 20 years to study the health effects of PFAS. In 2022, Hoppin’s team shared results with individuals and communities they tested, which showed that while GenX was not found in samples of participants, almost everyone in the study had PFAS in their blood unique to the Fayetteville Works plant.
Now, the researchers are following up with the group of over 1,000 people from across the Cape Fear River region tested in the initial rounds of the study. In the Fayetteville group, Hoppin said over a third of those participants have come back to give samples in this round of the study.
The study is focused more on clinical measures revealed with blood tests and looking at how those change over time with regard to PFAS exposure. This involves measuring things like cholesterol levels and thyroid hormones and doing a comprehensive metabolic panel that can reveal liver function and kidney function, Hoppin said.
“We're really interested in the next year in making some interactive maps so that people can look at how PFOA blood levels vary throughout the basin and over time, and trying to get some more accessible data that people can look at,” Hoppin said. “Even as we're starting to now look at some of the clinical outcomes, like liver enzymes and kidney markers — so starting to dig into some of the health pieces more.”
Hoppin emphasized the unique characteristics of the Fayetteville study group.
“Fayetteville is very interesting because everybody's exposure is different,” Hoppin said. “So in both Wilmington and Pittsboro, everybody's served by the same water source. And in Fayetteville, everybody's well has different levels of PFAS in it, everybody's house is somewhat different in how it's located next to the facility. And so we have a really unique opportunity to understand a lot more about exposure patterns, differences in exposures, how these chemicals track together.”
Hoppin said her team has already begun sharing individual test results and will share community-wide data based on scientific publications in progress within the next six months or so.
Carcinogenic chemicals
The International Agency for Research on Cancer, an intergovernmental agency forming part of the World Health Organization of the United Nations, has designated PFOA and PFOS as carcinogenic and possibly carcinogenic to humans, respectively.
These two long-chain PFAS have been phased out in the United States owing to health and environmental concerns, but remain prevalent in the environment and have been detected in blood samples from participants in the GenX Exposure Study.
The working group of 30 international experts — including Hoppin — reviewed extensive epidemiological studies to conduct a cancer hazard evaluation on PFOA and PFOS, according to the group’s report. They came to their conclusions by focusing on mechanistic evidence, which explores evidence of direct cause and effect; in this case, between PFOS and PFOA exposure and cancer.
Overall, the group determined there was enough evidence to officially classify PFOA as a “group 1” carcinogen or cancer-causing chemical. They determined that PFOS is possibly carcinogenic in humans, “group 2(b),” but more evidence was needed to support its cancer-causing effects.
Hoppin suggested that taking into account studies with large groups of people over time allowed the researchers to make a definitive conclusion that PFAS are capable of causing cancer. She said the GenX Exposure Study could be useful in making future cause-and-effect conclusions about cancer and PFAS exposure.
“One of the things that drove the making PFOA group 1 human carcinogen was the mechanistic data from epidemiology studies,” Hoppin said. “So, looking at the key characteristics of carcinogen: Do they impact the immune system? Do they result in epigenetic changes? These are kinds of questions that we can start to answer in a GenX study that's about 1,000 people. So we might be able to help inform that space on other PFAS.”
Still, Hoppin highlighted the complexity of tracking the chain of events between PFAS exposure and cancer. The process is made more difficult by the fact that most people don’t live in the same place their whole lives, so exposure levels are difficult to map directly to cancer, itself a disease that manifests in a number of ways. The small population sizes in rural communities, such as around the Fayetteville plant, also compounds these difficulties, she added.
“It's very rural, so it's going to be very difficult to identify enough cases of the same kind of cancer at the same point in time to really make causal arguments, which is not to say that we don't,” Hoppin said, “but it's just part of the challenge of that.”
In other words, Hoppin explained, PFAS exposure may have been a contributing factor to someone’s cancer, but with so many variables to consider, scientists aren’t yet able to say for certain whether drinking water with PFAS caused an individual’s disease.
“But it's just really hard, and it breaks my heart every time I'm talking to someone, because if they're impacted by cancer … that's the real story — is that cancer integrates over everything you've done over your life, and most people have moved around over their life.”
Contact Evey Weisblat at eweisblat@cityviewnc.com or 216-527-3608.
