Researchers led by NC State University have discovered that PFAS contamination in North Carolina’s groundwater could linger for over 40 years, posing long-term risks to residents and downstream water users.
A recent study led by researchers at North Carolina State University reveals that per- and polyfluoroalkyl chemicals (PFAS) could remain in the groundwater of Cumberland and Bladen counties in North Carolina for more than 40 years. The study shines a spotlight on the lingering effects of these persistent chemicals, which have been linked to serious health issues.
PFAS, commonly used in a variety of industrial applications, have been found to contaminate vast areas of groundwater. The research team employed an innovative technique, combining PFAS data, groundwater age-dating tracers and groundwater flux to project future PFAS concentrations.
“There’s a huge area of PFAS contaminated groundwater – including residential and agricultural land – which impacts the population in two ways,” lead author David Genereux, a professor of marine, earth and atmospheric sciences at NC State, said in a news release.
The researchers focused on groundwater samples from two watersheds near the Fayetteville Works fluorochemical plant.
Their findings indicated the presence of PFAS in groundwater up to 43 years old, with concentrations of hexafluoropropylene oxide-dimer acid (HFPO-DA) and perfluoro-2-methoxypropanoic acid (PMPA) averaging 229 and 498 nanograms per liter (ng/L), respectively.
These levels far exceed the U.S. Environmental Protection Agency’s maximum contaminant level (MCL) of 10 ng/L for HFPO-DA in drinking water.
“These results suggest it could take decades for natural groundwater flow to flush out groundwater PFAS still present from the ‘high emission years,’ roughly the period between 1980 and 2019,” Genereux added. “And this could be an underestimate; the time scale could be longer if PFAS is diffusing into and out of low-permeability zones (clay layers and lenses) below the water table.”
Despite the reduction in air emissions of PFAS since 2019, the study indicates that atmospheric deposition continues to contribute to groundwater contamination.
“Even a best-case scenario – without further atmospheric deposition – would mean that PFAS emitted in past decades will slowly flush from groundwater to surface water for about 40 more years,” added Genereux. “We expect groundwater PFAS contamination to be a multi-decade problem, and our work puts some specific numbers behind that.”
The implications of this lengthy contamination period are profound for the over 7,000 private well users and residents affected by downstream river water from the Cape Fear River. The study’s findings underscore the importance of addressing the persistent nature of PFAS and their long-term environmental impact.
Moving forward, the research team plans to expand their models to predict future PFAS concentrations at individual drinking water wells and collaborate with toxicologists to associate past PFAS levels with health outcomes.
The study was published in Environmental Science & Technology, with postdoctoral researcher Craig Jensen as the first author. The work was backed by the North Carolina Collaboratory and included contributions from experts at the University of Utah and the University of Nebraska.
By providing a detailed timeline for PFAS contamination, this research offers crucial insights that could guide future mitigation efforts and policies to protect public health and the environment.