Nafion byproduct 2 Found in Blood of Well Users Near Fayetteville, N.C.
Researchers from the GenX Exposure Study detected PFAS originating from a fluorochemical manufacturing plant – including Nafion byproduct 2 and GenX – in nearby private wells in Bladen and Cumberland Counties, N.C. PFAS refers to a group of chemicals called per- and polyfluoroalkyl substances.
“These compounds were released to the environment through air and wastewater emissions from the facility,” says Nadine Kotlarz, research scholar in the department of biological sciences at North Carolina State University, member of NC State’s Center for Human Health and the Environment (CHHE), and corresponding author of the paper.
“Air released from the facility caused the contamination of groundwater and private wells,” Kotlarz says. “In order to study how exposure to these chemicals may affect human health, we need to know the exposure levels across impacted people.”
In February 2019, the researchers recruited 153 people from this region who used 84 private wells to participate in the GenX Exposure Study. The participants lived within six miles of the fluorochemical facility. The participants provided well water and blood samples and filled out questionnaires about their well-water consumption.
The water and blood samples were screened for nine PFAS produced by the facility, including GenX and Nafion byproduct 2.
The PFAS found most frequently and at the highest concentrations in the wells included several low molecular weight PFAS (PMPA, PEPA, GenX, PFO2HxA, PFMOAA). The median concentration of GenX in the wells was 107 nanograms per liter (ng/L), 10 times higher than the U.S. Environmental Protection Agency’s (EPA) drinking water health advisory level of 10 ng/L.
However, these PFAS were not frequently detected in the private well users’ blood, even though they drank the well water.
Nafion byproduct 2, a higher molecular weight PFAS with a longer half-life, was detected frequently in wells at lower concentrations (the median concentration was 14 ng/L) and detected in more than half of participants’ blood.
“With Nafion byproduct 2, we saw that higher well-water concentration and the longer a person lived at their home correlated with higher blood levels,” Kotlarz says. “Well-water consumption is having an impact on exposure, and we know that several other PFAS were present in the wells, but due to the short half-lives of some PFAS (like GenX) in the body, we didn’t find all of the well water PFAS in blood.
“Blood levels of a chemical across a population are often used to characterize exposure,” Kotlarz says. “Without blood levels, we will need to estimate exposure to PFAS such as GenX another way in order to study their potential health effects.”
The research appears in the Journal of Exposure Science and Environmental Epidemiology. The GenX Exposure Study is supported by research funding from the National Institute of Environmental Health Sciences (1R21ES029353), NC State’s CHHE (P30 ES025128), the Center for Environmental and Health Effects of PFAS (P42 ES0310095), and the NC Policy Collaboratory. James McCord and Mark Strynar from the EPA; David Collier and Suzanne Lea from East Carolina University; Theresa Guillette of the Oak Ridge Institute for Science and Education Research; and Claire Critchley, Michael Cuffney, Zachary Hopkins, Detlef Knappe and Jane Hoppin of NC State also contributed to the work.
Note to editors: An abstract follows.
“Per- and polyfluoroalkyl ether acids in well water and blood serum from private well users residing by a fluorochemical facility near Fayetteville, North Carolina”
Authors: Nadine Kotlarz, Claire Critchley, Michael Cuffney, Zachary R. Hopkins, Detlef R.U. Knappe, Jane A. Hoppin, North Carolina State University; Theresa Guillette, Oak Ridge Institute for Science and Education Research; David Collier, C. Suzanne Lea, East Carolina University; James McCord, Mark Strynar, U.S. Environmental Protection Agency
Published: Jan. 10, 2024 in the Journal of Exposure Science and Environmental Epidemiology
BACKGROUND: A fluorochemical facility near Fayetteville, North Carolina, emitted per- and polyfluoroalkyl ether acids (PFEAs), a subgroup of per- and polyfluoroalkyl substances (PFAS), to air.
OBJECTIVE: Analyze PFAS in private wells near the facility and in blood from well users to assess relationships between PFEA levels in water and serum.
METHODS: In 2019, we recruited private well users into the GenX Exposure Study and collected blood and well water samples. We targeted 26 PFAS (11 PFEAs) in water and 27 PFAS (9 PFEAs) in serum using liquid chromatography-mass spectrometry. We used regression modeling to explore relationships between water and serum PFAS. For the only PFEA detected frequently in water and serum, Nafion byproduct 2, we used generalized estimating equation (GEE) models to assess well water exposure metrics and then adjusted for covariates that may influence Nafion byproduct 2 serum concentrations.
RESULTS: We enrolled 153 participants ages 6 and older (median=56 years) using 84 private wells. Most wells (74%) had ≥6 detectable PFEAs; median ∑PFEAs was 842 ng/L (interquartile range=197-1,760 ng/L). Low molecular weight PFEAs (PMPA, HFPO-DA [GenX], PEPA, PFO2HxA) were frequently detected in well water, had the highest median concentrations, but were not detectable in serum. Nafion byproduct 2 was detected in 73% of wells (median=14 ng/L) and 56% of serum samples (median=0.2 ng/mL). Cumulative dose (well concentration × duration at address) was positively associated with Nafion byproduct 2 serum levels and explained the most variability (10%). In the adjusted model, cumulative dose was associated with higher Nafion byproduct 2 serum levels while time outside the home was associated with lower levels.
SIGNIFICANCE: Serum biomarkers were not good measures of long-term exposure to low molecular weight PFEAs in a private well population. For Nafion byproduct 2, well water exposure metrics were associated with serum levels, particularly when incorporating exposure duration.
This post was originally published in NC State News.