Researchers from the GenX Exposure Study have detected PFAS (per- and polyfluoroalkyl substances) associated with a nearby fluorochemical plant in the household dust of homes located in Cumberland and Bladen counties, North Carolina. Homes closer to the plant had higher concentrations of those specific PFAS than homes located farther away.
Additionally, the researchers detected high levels of other PFAS not necessarily associated with the fluorochemical plant in over 90% of samples taken from homes. Overall, the findings indicate that household dust can be an additional PFAS exposure source.
"PFAS exposure via contaminated well water is relatively well studied but, given the air emissions from the plant, we wanted to learn whether household dust was also a source of exposure," says Nadine Kotlarz, assistant professor of civil, construction, and environmental engineering, member of North Carolina State University's Center for Human Health and the Environment (CHHE), and corresponding author of the work.
In February 2019, the team collected dust samples from 65 homes located within ~6 miles (9 km) of the plant; these homes had previously undergone well-water testing as part of the GenX Exposure Study. They targeted 48 PFAS, including 12 PFEAs (or per- and polyfluoroalkyl ether acids, a subset of PFAS) specifically associated with the fluorochemical plant that were also detected in the drinking water wells of nearby residents. They also included ultrashort chain PFAS in the testing due to increasing reports of their presence in dust and people.
Every dust sample had at least one PFAS detected. GenX was present in 89% of the samples, and an additional six of the 12 PFEAs were detected in over 75% of the samples. Dust concentrations of six PFEAs (PEPA, PMPA, PFMOAA, PFO2HxA, GenX, and Nafion byproduct 2) decreased significantly as home distance from the fluorochemical plant increased.
The team also found TFA, an ultrashort chain PFAS, in 89% of dust samples. This compound had the highest median concentration of the 48 targeted PFAS in the study. Ultrashort chain PFAS like TFA are an emerging class of PFAS that originate from breakdown of refrigerants.
"For people living near the fluorochemical facility, it would be natural to wonder how important dust exposure may be," says Jane Hoppin, environmental epidemiologist at NC State and principal investigator of the GenX Exposure Study.
"Generally speaking, we know that dust exposure can contribute to overall exposure, and that small children tend to have higher dust exposures than adults," Hoppin says. "This study demonstrates the need for evaluating household dust for PFAS in impacted communities. Additionally, we need to identify the sources of short chain PFAS, such as TFA."
The study appears in Environmental Science and Technology and was supported by research funding from the National Institute of Environmental Health Sciences (1R21ES029353), NC State's Center for Human Health and the Environment, the Center for Environmental and Health Effects of PFAS (P42 ES0310095), and the NC Policy Collaboratory. Susie Proctor, former research assistant at NC State and current Ph.D. student at University of Michigan, is first author. Sharon Zhang and Heather Stapleton of Duke University's Nicholas School of the Environment developed the analytical method and performed the dust PFAS analyses. Other NC State contributors were Jane Hoppin and Detlef Knappe.
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