Researchers tested over 700 private well and public drinking water sources and found that tap water from urban areas or regions previously contaminated with forever chemicals were more likely to contain the chemical compounds.
Because per-and poly-fluoroalkyl substances (PFAS), also known as "forever chemicals," don't break down easily, they are currently found in virtually every aspect of the environment, including soil, air, and water. Though manufacturers in the United States no longer use forever chemicals, companies in other countries still use PFAS to produce products.
Research suggests that PFAS can cause reproductive harm, developmental delays in children, and increase the risk of some types of cancer. What's more, news reports indicate that PFAS manufacturers DuPont and 3M knew about the dangers of forever chemicals and kept this information hidden from the public for over 40 years.
In addition, humans are likely exposed to PFAS through contaminated drinking water, and earlier estimates indicate that in the U.S., about 200 million people have drinking water sources that contain unsafe PFAS levels.
To address the issue, the Environmental Protection Agency (EPA) proposed new PFAS limits in drinking water, which, if finalized, would require public water sources to monitor forever chemicals and lower the levels if they exceed the limits.
Now, in a recent study, researchers with the U.S. Geological Survey (USGS) — a U.S. government scientific research agency — tested over 700 private-well and public-supply tap water samples from across the U.S. for PFAS. Using modeling based on those samples, they estimate that 45% of drinking water sources nationwide could contain at least one PFAS compound.
The USGS researchers obtained tap water samples from 269 private wells and 447 public water sources from various locations in the U.S. between 2016 and 2021. They retrieved the samples primarily from residences and sampled some schools, national parks, and urban centers near industrial sites.
Using three laboratories, the team tested the samples for 32 forever chemical compounds.
In about 15% of the samples, the scientists observed 17 PFAS at least once, with PFBS, PFHxS, and PFOA found most frequently. Moreover, PFOA and PFOS concentrations averaged around four parts per trillion, which is the limit proposed by the EPA.
In addition, PFAS profiles and estimated concentrations were similar among private wells and public supply tap water.
The study also found PFAS in water sources in approximately 70% of urban areas or locations known to have previous PFAS contamination. In contrast, only 8% of rural regions sampled had PFAS present.
Moreover, PFAS in drinking water may be more common in the Great Plains, Great Lakes, Eastern Seaboard, and Central/Southern California regions.
Based on the data, the scientists estimate that nearly half of tap water in the U.S. could contain at least one forever chemical.
However, according to The Hill, lead author and USGS research hydrologist Kelly Smalling notes, "What this study has shown us is that even though it's estimating that 45 percent of U.S. taps could have at least one PFAS, we also show that there are huge swaths of the country where PFAS was not detected, and I think that's good news."
- EPA. Our Current Understanding of the Human Health and Environmental Risks of PFAS.
- EPA. Biden-Harris Administration Proposes First-Ever National Standard to Protect Communities from PFAS in Drinking Water.
- Environment International. Per- and polyfluoroalkyl substances (PFAS) in United States tapwater: Comparison of underserved private-well and public-supply exposures and associated health implications.
- The Hill. New study estimates 'forever chemicals' may be found in 45 percent of U.S. tap water.
- EPA. Reducing PFAS in Drinking Water with Treatment Technologies.