Although levels of older “forever” chemicals have declined in many foods over the past 20 years, a new study shows that drinking water, seafood, eggs, and brown rice remain significant sources of PFAS exposure for adults.
For years, food has been seen as a key way people are exposed to PFAS, a group of long-lasting chemicals found in everything from industrial materials to everyday consumer products. These “forever chemicals” are known to linger in the environment and have been linked to serious health risks. But there’s encouraging news.
A new study from researchers at the Boston University School of Public Health (BUSPH) finds that PFAS exposure through food has actually declined among adults over the past 20 years. However, the study also highlights that drinking water is still a significant source of PFAS exposure.
Published in the journal Environmental Science & Technology, the research looked at how diet and drinking water relate to blood levels of “legacy” PFAS—older chemicals that were phased out in the United States in the early 2000s. The team analyzed blood samples from California residents and found that PFAS exposure was linked to eating seafood, eggs, and brown rice. Surprisingly, they found fewer food-related connections than earlier studies suggested.
The researchers also discovered that people living in areas with detectable PFAS in their tap water had higher levels of the chemicals in their blood. However, these levels were lower than those found in severely contaminated regions.
Regulatory Context and Public Health Implications
The findings published the same day the Environmental Protection Agency (EPA) announced that it will roll back first-ever limits on certain types of PFAS in drinking water, set last year. The EPA also said it will uphold drinking water standards for two of the most harmful forever chemicals—PFOA and PFOS—but extended the deadline for water utilities’ compliance with these rules, from 2029 to 2031.
The study provides the first analysis of the effects of diet and drinking water simultaneously on PFAS concentrations in blood, and it fills a critical gap in research on this topic. Most US information on PFAS in food relies on earlier European studies that cannot be fully applied to the US population or lifestyle due to differences in time of sampling, diet, food production, and industries. To understand and mitigate the harmful effects of PFAS on individuals and the environment, the US needs current data on the possible contributing sources of exposure.
While we observed fewer dietary associations compared to previous studies, diet and water may still be an important source of exposure in the general population,” says study lead and corresponding author Dr. Emily Pennoyer, a graduate of BUSPH’s environmental health PhD program, and a student at the time of the study. “These findings emphasize the need to continue ongoing efforts to regulate PFAS in drinking water.”
Known as “forever chemicals” because they are difficult to break down, some PFAS are linked to a number of diseases and other health conditions, including multiple cancers, liver damage, thyroid disease, decreased vaccine response, and developmental and reproductive complications.
Shifts in Dietary PFAS Exposure
For the study, Dr. Pennoyer and colleagues at BUSPH, the California Department of Public Health (CDPH), and California Department of Toxic Substances Control estimated associations among legacy serum PFAS concentrations, self-reported food consumption, and PFAS concentrations in public drinking water supplies. The 700 adult participants were selected from the California Regional Exposure Study, conducted from 2018-2020, which measures and compares environmental chemicals in people across the state to better understand how to reduce chemical exposure and improve public health.
The participants provided survey responses detailing demographic information and the frequency in which they consume red meat, poultry, seafood, dairy, eggs, potatoes, brown rice, takeout, and packaged foods that are heated at home. The researchers observed associations between legacy serum PFAS and consumption of seafood, eggs and brown rice, but overall, PFAS exposure through food appeared to be lower than earlier studies in other populations—a surprising result to the team. This decline could be due, in part, to the Food and Drug Administration’s decision to phase out legacy PFAS from manufacturing, and restrict certain PFAS in paper food contact materials.
“It is encouraging that we see fewer associations with food in this study, but concern about PFAS in some food groups remain,” says study coauthor Dr. Nerissa Wu, biomonitoring California program lead at CDPH. “We will continue to work to understand how to lower PFAS levels in the California food supply.”
Water Quality Still a Concern
While PFAS concentrations in the participants’ drinking water was on average substantially lower than previous measurements in areas that have reported heavily contaminated water supplies, the team still observed significantly higher PFAS levels in participants living in water service areas with detectable PFAS, compared to those who lived in areas without detectable levels.
“The connections to drinking water are concerning and support California’s efforts to evaluate and address PFAS contamination in drinking water supplies,” says study coauthor Dr. Kathleen Attfield, head of the Biomonitoring California, Exposure Surveillance and Epidemiology Unit at CDPH.
In addition to gaining a better understanding of PFAS in the food chain, “more research is needed on indoor exposures to air, dust, and cosmetics, as well as analyses of newer, non-legacy PFAS,” says study senior author Dr. Thomas Webster, professor of environmental health at BUSPH.
“Our findings further support the importance of upholding the federal drinking water standards promulgated by the U.S. Environmental Protection Agency,” says study coauthor Dr. Wendy Heiger-Bernays, emeritus clinical professor of environmental health at BUSPH. ”Efforts to ban or limit the use of PFAS, including emerging PFAS, are necessary to reduce their presence in the environment, including in food and water.”
Consumers can make informed choices by purchasing products labeled “fluoro-free” when possible, she adds.
Reference: “Exposure to Legacy Per- and Polyfluoroalkyl Substances from Diet and Drinking Water in California Adults, 2018–2020” by Emily H. Pennoyer, Toki Fillman, Wendy Heiger-Bernays, Kathleen R. Attfield, Hyoung-Gee Baek, Songmei Gao, Sabrina Smith, June-Soo Park, Nerissa Wu and Thomas F. Webster, 14 May 2025, Environmental Science & Technology.
DOI: 10.1021/acs.est.4c11872
Funding: Centers for Disease Control and Prevention, National Institute of Environmental Health Sciences
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3 Comments
While the research article makes very clear that only a relatively small number of ‘legacy’ PFAS types were studied, this summary doesn’t do a good job of translating the import of that limitation to the reader. Some legacy forms such as PFOA and PFOS have been phased out for most uses for more than a decade, so it isn’t terribly surprising that these are declining in blood. However, many new forms of PFAS, typically shorter chain and with little research on health effects of exposure, have replaced the legacy forms. The authors conclude “Future work should also consider additional PFAS and exposure pathways, including inhalation of precursor compounds in the indoor environment, which might be important contributors to PFAS body burden..”
It’s a long article to read to discover that I probably can’t do much to avoid them. Eat the best quality food you can afford and get on with your life I suggest.
Yeah could be… right… as how many places that are for healthy choices all fight to get rid of laws that keep unsafe stuff out of food. Almost all of them getting attention. What’s Trumps stance in banning harmful stuff the rest of the world had already cause it’s killing people? Is he fir the peoples health or big business making cheap money at our healths expense.