Summary
This study examined per- and polyfluoroalkyl substances (PFAS) in wastewater and their potential impact on drinking water contamination in the United States. PFAS are a large group of chemicals used in many industrial and consumer products and are known for their persistence in the environment.
Researchers analyzed wastewater from eight large municipal treatment facilities and found that the six PFAS compounds currently regulated in U.S. drinking water standards make up only a small portion (about 7–8%) of the total fluorinated chemicals present. Even when including 18 commonly measured PFAS compounds, they represented only 11–21% of the total extractable organofluorine (EOF). Most of the remaining fluorinated compounds were mono- and polyfluorinated pharmaceuticals.
The study also showed that wastewater treatment removed less than 25% of these fluorinated substances, meaning large amounts can still enter waterways. Based on national modeling, researchers estimated that wastewater discharges could contaminate drinking water sources for up to 23 million Americans above regulatory thresholds.
Overall, the findings highlight that current PFAS regulations address only a small fraction of fluorinated chemicals present in wastewater, emphasizing the need for better control of PFAS sources and further research into the environmental fate and health effects of fluorinated pharmaceuticals.
PMID: 39761386
PMCID: PMC11761303
DOI: 10.1073/pnas.2417156122
Abstract
Wastewater receives per- and polyfluoroalkyl substances (PFAS) from diverse consumer and industrial sources, and discharges are known to be a concern for drinking water quality. The PFAS family includes thousands of potential chemical structures containing organofluorine moieties. Exposures to a few well-studied PFAS, mainly perfluoroalkyl acids (PFAA), have been associated with increased risk of many adverse health outcomes, prompting federal drinking water regulations for six compounds in 2024. Here, we find that the six regulated PFAS (mean = 7 to 8%) and 18 measured PFAA (mean = 11 to 21%) make up only a small fraction of the extractable organofluorine (EOF) in influent and effluent from eight large municipal wastewater treatment facilities. Most of the EOF in influent (75%) and effluent (62%) consists of mono- and polyfluorinated pharmaceuticals. The treatment technology and sizes of the treatment facilities in this study are similar to those serving 70% of the US population. Despite advanced treatment technologies, the maximum EOF removal efficiency among facilities in this work was <25%. Extrapolating our measurements to other large facilities across the United States results in a nationwide EOF discharge estimate of 1.0 to 2.8 million moles F y-1. Using a national model that simulates connections between wastewater discharges and downstream drinking water intakes, we estimate that the sources of drinking water for up to 23 million Americans could be contaminated above regulatory thresholds by wastewater-derived PFAS alone. These results emphasize the importance of further curbing ongoing PFAS sources and additional evaluations of the fate and toxicity of fluorinated pharmaceuticals.