PFAS pollution led to contamination of US drinking water wells, study finds
Pollution by toxic PFAS “forever chemicals” in America’s aquifer system has led to widespread contamination of private and public drinking water wells, data from a new study by the US Geological Survey finds.
The study, published in Environmental Science and Technology, detected PFAS chemicals in 20% of private wells and 60% of public wells sampled in 16 eastern states, and offered new insights on how to predict which drinking water sources may be contaminated.
Previous analyses have detailed the chemicals’ ubiquity in municipal water systems, but less is known about the scope of the problem in the nation’s private wells, from which about 43 million people get their water.
“This should set off alarm bells for anyone relying on private well water,” said Scott Faber, vice-president of government affairs with the Environmental Working Group, which tracks PFAS issues. “One out of five people getting their water from wells could be drinking PFAS – that’s a big number.”
PFAS, or per-and poly-fluorakyl substances, are a class of more than 9,000 compounds typically used across dozens of industries to make products water-, stain- or heat-resistant. They’re in thousands of everyday consumer products such as stain guards, cookware and waterproof clothing, and are common in industrial manufacturing.
The chemicals are linked to cancer, birth defects, liver disease, thyroid disease, decreased immunity, hormone disruption and a range of other serious health problems. They’re dubbed “forever chemicals” because they do not naturally break down, and they also easily move through the environment, often ending up in drinking water.
Analyses of public utility records have found the chemicals to be contaminating water supplies for well over 100 million Americans, though estimates largely don’t cover private wells. No comprehensive private well monitoring system exists, many water quality standards don’t apply to them and filters installed in private wells often aren’t designed to capture PFAS.
“Well owners are flying blind,” Faber said.
The USGS undertook the analysis to provide data that could help regulators identify areas and wells that are at higher risk for PFAS contamination, though the data won’t automatically trigger new testing.
Broadly, the research found higher concentrations in areas “affected by modern human activity” like urbanization, said Peter McMahon, one of the study’s co-authors. The chemicals were also found at a higher rate near facilities that commonly use PFAS products, like airports, military bases and chemical plants, or landfills that often leak the compounds into groundwater.
Wells’ depth also plays a role, McMahon noted. Those drawing from deeper and “older” groundwater shielded from contaminated precipitation had less PFAS, while wells pulling from shallow, “modern” aquifers that cycle in contaminated surface water or rain have higher concentrations.
Though wells near Memphis, Tennessee are in an urbanized area, the region’s deep, old water aquifer is largely clean, while nearly every well tested that relies on shallow aquifers in the Ohio Valley or New England regions had some PFAS in it. Aquifers with higher levels of pharmaceuticals and organic material also had elevated PFAS levels.
The USGS took 254 samples from drinking water wells that draw from a network of five groundwater aquifers stretching from Maine to Illinois to Florida. The study looked for 24 kinds of PFAS and detected 14. Levels in a public West Virginia well reached about 1,500 parts per trillion (ppt), which is well above a level that public health advocates warn could cause health problems. The Environmental Protection Agency set a health advisory limit of 70ppt, though some states have limits as low as 1ppt.
The study’s authors noted most samples found multiple types of PFAS, though little is known about how those toxic mixes impact health, and contamination levels could be much higher because thousands of PFAS compounds exist, but regulators typically only check for about 30.
Though the PFAS crisis has come into sharper focus in recent years and the chemicals’ health risks have been clear for decades, the EPA has so far failed to act on setting enforceable water limits. The agency is proposing to set limits on two types of PFAS compounds in drinking water by 2023, but that still leaves thousands unaccounted for, and the agency has previously missed similar deadlines.
In the absence of meaningful federal oversight, many states have begun setting drinking water limits. But most of the 16 states from which the USGS checked samples don’t have any standards in place, which leaves it up to well owners to protect themselves.
That underscores how regulators have “failed us”, Faber said, and highlights the need to ban further PFAS production.
“This is the kind of regulatory failure that should upset every American,” he added. “It should light a fire under legislators who represent rural states with contaminated military bases and industrial facilities.”