PFAS drinking water

February 26, 2025

New data show widespread chemical contamination of drinking water

By Douglas Main

A newly released trove of data reveals widespread pollution of US tap water with more than 320 chemical contaminants, including industrial chemicals and farm-related pollutants.

The latest information is part of a tap water database, created by the Environmental Working Group (EWG), and incorporates information from nearly 50,000 water systems collected between 2021 and 2023.

Though few chemicals were found exceeding the federal government’s legally mandated maximum contaminant level (or MCL), almost all US water systems nation-wide contained at least one contaminant at levels that surpassed the health guidelines developed by EWG that are based on scientific research of the harms associated with the various contaminants.

“This is a wake-up call,” said Tasha Stoiber, an EWG senior scientist. “Outdated federal regulations continue to leave millions of people at risk of exposure to harmful substances.”

Among the chemicals commonly detected were per- and polyfluoroalkyl substances (PFAS), also known as forever chemicals, which were found in the water of at least 143 million Americans. Nitrates, a common waste product from farming operations linked to colorectal cancer and thyroid disease, were also commonly detected as well as disinfection byproducts caused by using chlorine.

Many of these disinfection byproducts — including chemicals called trihalomethanes, chloroform, haloacetic acids, and more — showed up in tens of thousands of water systems at concentrations far above what many health scientists consider safe.

January 6, 2025

Fluorinated drugs, a type of PFAS, widely contaminating US drinking water

By Douglas Main

New research suggests that fluorinated pharmaceuticals — a category that includes well-known medications such as Prozac and Flonase — are showing up in the water supply of millions of people. These drugs and their breakdown products are technically classified as being per- and polyfluoroalkyl substances (PFAS), also known as “forever chemicals,” which as a chemical class is the subject of worldwide health concern.

A study published January 6 in Proceedings of the National Academy of Sciences found that the bulk of PFAS entering and exiting wastewater treatment plants is made up of these fluorinated drugs. Notably, the researchers determined that the pharmaceuticals were largely not removed from the water by conventional wastewater treatment practices.

This pharmaceutical material “doesn’t get treated in the wastewater treatment plant, and it doesn’t break down,” said Bridger Ruyle, study co-author and researcher at New York University. “And we know [these chemicals] can be re-entering drinking water supplies.”

The study estimates that this material contaminates the water supply of around 23 million Americans, Ruyle said.

These drugs enter wastewater after being excreted by people. About 50% of drinking water utilities are located downstream of a wastewater outflow plant and regularly use varying amounts of this water.

A slight majority of this material was made up of only four drugs and one of their metabolites: the arthritis medication Celecoxib (Celebrex); flecainide (Tambocor), prescribed for arrhythmia; maraviroc (Selzentry), and one of its metabolites, used to treat HIV; and sitaglipt (Januvia), a diabetes drug.

“We don’t know that much about what the exposures or health risks are” for those drinking small concentrations of this material, Ruyle said.

November 7, 2023

PFAS chemicals found in 71% of tested Wisconsin wells

By Shannon Kelleher

The majority of private wells providing water for 450 Wisconsin homes tested positive for harmful chemicals, though mostly at low levels, according to a new study.

The analysis, published November 2, tested the wells for 44 types of per- and polyfluoroalkyl substances (PFAS). Researchers found that 71% of the wells were contaminated with 4% of the private wells containing PFAS levels that exceeded the Environmental Protection Agency (EPA)’s proposed maximum contaminant levels. Roughly 1% had PFAS levels above the state’s recommended groundwater standards. The researchers said their work is the first to sample shallow groundwater away from known PFAS contamination sites in the state. Examining well water is important because about one quarter of Wisconsin residents get their drinking water from over 800,000 private wells.

“A big takeaway is we found PFAS in the majority of wells, but at very small levels in most of those locations,” said Steven Elmore, program director of the Bureau of Drinking Water and Groundwater at the Wisconsin Department of Natural Resources (DNR). To find it at detectable levels in shallow groundwater is not surprising, he said, noting that PFAS has been found in rainwater across the country and in Lake Michigan and Lake Superior, which flank the state.

The study was a collaboration between the Wisconsin Department of Natural Resources, the University of Wisconsin – Stevens Point, and the Wisconsin State Laboratory of Hygiene through the University of Wisconsin-Madison. It was funded by the US Environmental Protection Agency.

There are over 12,000 types of PFAS, many of which cannot be detected in water using currently available tests. These so-called “forever chemicals” do not break down naturally and can leach into drinking water from industrial sites, sewage treatment plants, landfills, or certain firefighting foams. A 2022 analysis found detectable PFAS levels in about 83% of US waterways. A recent study found that exposure to some PFAS may increase thyroid cancer risk, while past research has linked the chemicals to health problems including kidney cancer, testicular cancer, and ulcerative colitis.

The companies 3M, DuPont, and others agreed to settlements over the summer that will provide communities with billions of dollars to test for PFAS and remove them from drinking water. Last month, three residents of New Milford, Connecticut filed a lawsuit alleging that the Aquarion Water Company provided water to the public that it knew was contaminated with elevated PFAS levels.