TRAVERSE CITY, Michigan (AP) — The drinking water from nearly half of the faucets in the United States likely contains “perpetual chemicals” that can cause cancer and other health problems, according to a government study released Wednesday.
The synthetic compounds, collectively known as PFAS, contaminate drinking water in cities and towns large and small — as well as in private wells and public systems — to varying degrees, according to the US Geological Survey.
The researchers called the study the first nationwide attempt to test tap water from private sources in addition to regulated sources for PFAS. It builds on previous scientific evidence that the chemicals are widespread, found in consumer products as diverse as non-stick pans, food packaging and waterproof clothing, and entering water supplies.
Because the USGS is a scientific research agency, the report contains no policy recommendations. But the information “can be used to assess the risk of exposure and make decisions about whether to treat your drinking water, have it tested, or get more information from your state” about the situation on the ground, said lead author Kelly Smalling, a research hydrologist.
The US Environmental Protection Agency in March proposed the first federal drinking water limits for six forms of PFAS, or per- and polyfluorinated substances, that persist in the human body for years and do not break down in the environment. A final decision is expected later this year or in 2024.
But the government hasn’t banned companies that use the chemicals from discharging them into public sewers, Scott Faber, senior vice president of the Environmental Working Group, told an advocacy group.
“We should tackle this problem where it starts, rather than putting up a traffic light after the accident,” he said. “We should require polluters to treat their own waste.”
Studies in laboratory animals have revealed possible links between PFAS chemicals and some types of cancer, including kidney and testicular cancer, as well as problems such as high blood pressure and low birth weight.
Federal and state programs typically measure exposure to pollutants such as PFAS at water treatment plants or groundwater wells that feed them, Smalling said. In contrast, the USGS report was based on samples from faucets at 716 locations, including 447 that rely on public supplies and 269 that use private wells.
The samples were taken from different locations between 2016 and 2021 – mainly in homes, but also in some schools and offices. These included protected areas such as national parks; Residential and rural areas with no identified PFAS sources; and urban centers with industrial or waste dumps known to generate PFAS.
Most taps were only sampled once. Three were sampled multiple times over a three-month period with little change in results, Smalling said.
Scientists tested 32 PFAS compounds – most of which were detectable using available methods. There are thought to be thousands more, but they can’t be detected with current technology, Smalling said.
The most frequently found types were PFBS, PFHxS and PFOA. PFOS, one of the most common in the country, was also a frequent occurrence.
Positive samples contained up to nine varieties, but most were closer to two. The median concentration was about seven parts per trillion for all 32 types of PFAS, although it was about four parts per trillion for both PFOA and PFOS — the limit the EPA has proposed for these two compounds.
The heaviest loads were in cities and near potential sources of the compounds, particularly on the east coast; Great Lakes and Great Plains town centers; and Central and Southern California. Many tests, especially in rural areas, failed to detect PFAS.
Based on the data, the researchers estimated that at least one form of PFAS could be found in about 45% of tap water samples nationwide.
The study underscores that private well users should have their water tested for PFAS and consider installing filters, said Faber of the Environmental Working Group. Filters with activated carbon or reverse osmosis membranes can remove the compounds.
The USGS study is “further evidence that PFAS is incredibly prevalent and people who rely on private wells are particularly vulnerable to the harm caused by these chemicals,” Faber said.