Nearly 7 percent of Americans may be exposed to hazardous levels of "forever chemicals" through treated municipal wastewater, a new study has found.
These approximately 23 million people may be consuming these toxic compounds, also known as per- and polyfluoroalkyl substances (PFAS), in their drinking water, according to the study, published on Monday in the Proceedings of the National Academy of Sciences.
They are doing so due to the failure of wastewater treatment facilities to effectively remove PFAS from their purified water streams, which ultimately reenter municipal drinking water networks, the study authors found.
And that figure is only likely to rise, since treated wastewater continues to make up an increasingly significant proportion of drinking water resources, the researchers warned.
There are thousands of types of PFAS, synthetic compounds found in a variety of household products, waterproof apparel, industrial discharge and certain types of firefighting foam.
These so-called forever chemicals persist in both the human body and in the environment, and many have been linked to cancers and other serious illnesses.
While the Environmental Protection Agency (EPA) established drinking water regulations for six types of PFAS last year, those are only six of as many as 15,000.
A team of scientists led by Bridger Ruyle, an environmental engineer at New York University, set out to track the presence of organofluorines — a family of compounds that includes PFAS and are often ingredients in prescribed medications — in the wastewater of eight large municipal treatment systems.
Ruyle and his colleagues found that as much as 75 percent of the extractable organofluorine present in the treated wastewater contained pharmaceuticals that are not currently subject to EPA regulations. The six regulated PFAS, meanwhile, made up less than 10 percent of the extractable organofluorines, according to the study.
Even though these systems — which resemble those serving about 70 percent of the US population — employ advanced sewage treatment technologies, their maximum efficiency rate for removing organofluorines was less than 25 percent.
Based on results from a national wastewater dilution model, the authors calculated that PFAS discharges in wastewater may be permeating the drinking water supplies of as many as 23 million Americans.
"These results emphasize the importance of further curbing ongoing PFAS sources and additional evaluations of the fate and toxicity of fluorinated pharmaceuticals," the authors stated.
Nonetheless, the researchers also acknowledged that realizing such goals will be complex, as U.S. regulators typically consider risks associated with individual toxicants, rather than the complex mixtures that exist in wastewater.
"This poses a challenge for regulating PFAS, pharmaceuticals, and other organofluorine compounds because there are potentially tens of thousands of these chemicals in commerce," the authors noted.
While the researchers stressed that experts have widely called for a class-based method for regulating PFAS, industry voices have long been opposed to such an approach.
The authors also acknowledged that the U.S. Food and Drug Administration "does not consider the environmental persistence and secondary human and ecological exposures to pharmaceuticals."
Ultimately, the scientists called for further research that would include random samplings of a wider array of diverse wastewater treatment plants, as well as improvements to wastewater quality management and infrastructure.
"Pharmaceuticals that are persistent enough to reenter drinking water supplies, such as the highly recalcitrant organofluorine compounds in this study, could therefore affect otherwise healthy and/or sensitive human populations," the researchers added.