Wastewater treatment facilities are a major source of PFAS contamination in U.S. drinking water, estimated to contain enough “forever chemicals” to raise concentrations above safe levels for more than 15 million people. is being discharged. It also has the potential to release long-lasting prescription drugs into the water supply.

Although these plants purify wastewater, they do not destroy all the contaminants added upstream, and the remaining chemicals are released into the same waterways that provide drinking water. “This is a funnel into the environment,” he says bridger lyle at New York University. “We capture different things from different places and release them all in one place.”

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are of particular concern because they contain carbon-fluorine bonds and are highly persistent in the environment. Regular exposure to several types of PFAS is associated with an increased risk of many health problems, from liver damage to various forms of cancer. The U.S. Environmental Protection Agency (EPA) recently established strict drinking water limits for six of the most well-studied PFAS.

Wastewater treatment facilities are a known source of PFAS contamination worldwide. sewage sludge It is produced as a by-product and sometimes used as fertilizer. To determine whether similar contamination remained in treated water, Ruyle and his colleagues measured concentrations of PFAS and other molecules containing carbon-fluorine bonds in wastewater at eight large treatment facilities across the United States. .

Their findings suggest that wastewater treatment plants across the United States release tens of thousands of kilograms of fluorine-containing compounds into the environment each year, including significant amounts of PFAS. Once the treated wastewater leaves the facility, it mixes with natural water from rivers and lakes. “That would create downstream drinking water issues,” Lyle said.

Applying these numbers to a model of the U.S. drinking water system, the researchers estimated that wastewater could cause PFAS concentrations in the drinking water of approximately 15 million people to exceed EPA limits. In times of drought, as natural water for diluting wastewater decreases, models suggest that concentrations rise above the limit by up to 23 million people. And Ruyle says these may be conservative estimates. Their model assumes that natural water is already free of PFAS.

“This shows that wastewater treatment facilities are a very important source of these compounds,” he says. Carsten Plasse The professor at Johns Hopkins University in Maryland was not involved in the study. Although there are ways to remove or destroy PFAS in water, and more drinking water facilities are installing such systems, currently “our wastewater treatment plants are not set up to deal with this.” he says.

While chemicals alone will forever be a problem, researchers also found that PFAS only make up a small portion of the total amount of fluorinated chemicals emitted by facilities. Most were not PFAS, but other compounds used in common medications such as statins and SSRIs. These drugs are also a concern for ecosystems and people.

“Another person could be taking a cocktail of fluoridated prescription drugs,” Lyle says. But the effects of low doses and long-term exposure to such compounds are not well understood, he says.

“We need to start having a conversation about whether we should use more fluoride in medicines,” Ruiru says. Fluoridation is widely used in medicines to increase their effectiveness in the body, but “preventing widespread chemical contamination should also be important,” he says.