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What Are “Forever Chemicals” and Why Are They in Our Water?

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We’ve got more on how these culprits can impact your health.

An alarming new study suggests that more than 200 million Americans could be exposed to “forever chemicals” in their tap water. We’re breaking down what these scary-sounding compounds are, how they affect the body, and what you can do to protect yourself.

Are there forever chemicals in tap water?

New testing from the Environmental Protection Agency has discovered that “forever chemicals,” so-called because they’re virtually indestructible and don’t degrade, have found their way into the drinking water of 70 million people in the U.S. But the agency has only surveyed about a third of America’s public water systems, meaning that the EPA is on track to find as many as 200 million people — or at least 60 percent of the U.S. — could be exposed, the Guardian reports.

The findings are in line with previous studies, which have determined that these toxins are fairly common in our water supply. A U.S. Geological Survey report last year found the chemicals in 45 percent of our nation’s tap water.

Researchers in that study tested for 32 of these chemicals, known formally as perfluorinated and polyfluorinated alkyl substances (PFAS), which have been linked to several serious conditions, including cancer. The median concentration they found was around 7 parts per trillion. But for two particular substances, PFOA and PFOS, the concentration was about 4 parts per trillion. Cities — particularly on the East Coast, in the Great Lakes and Great Plains region, and in Central and Southern California — had the highest levels of PFAS, while many rural areas didn’t appear to have any, the AP reports

The USGS study was released just weeks before the chemical and manufacturing behemoth 3M reached a $10.3 billion settlement with American cities and towns over claims they polluted water with PFAS. (For more, check out Katie’s 2023 interview with the attorney working on this case below.)

Last year, the Environmental Protection Agency proposed new standards that would limit PFAS. The guidelines would force water utilities to restrict two common types of PFAS (called PFOA and PFOS) to 4 parts per trillion, which is the lowest level at which they can be reliably detected. It’s only recently become clear how dangerous these chemicals can be, and the EPA’s previous guidance, issued in 2016, advised a much higher limit, at 70 parts per trillion, the Washington Post reports.

Some states have recently enacted their own forever chemical standards. These federal guidelines would be as tough or tougher than those rules, reducing exposure for nearly 100 million Americans, the EPA estimates. Radhika Fox, an EPA administrator, tells the Associated Press that the new rules would be a “transformational change” for improving the safety of drinking water in the U.S. 

“The science is clear that long-term exposure to PFAS is linked to significant health risks,” she says.

Do water filters remove forever chemicals?

David Andrews, a senior scientist with the Environmental Working Group, tells CNN that the filters most effective at ridding water of forever chemicals use reverse osmosis. Granular activated carbon filters, which are more common and less expensive, aren’t as effective but can still remove a large number of other contaminants, he says.

It’s also very important to regularly change your filters. If you don’t, they may become saturated, which could actually raise the levels of PFAS in your water, Andrews says.

If all this is making you want to upgrade your water filter, Wirecutter suggests looking for one that’s NSF-certified to remove PFOA and PFOS. (They recommend the Aquasana AQ-5200 and the A.O. Smith filter.)

What are PFAS, and how do they affect your health?

PFAS were engineered to repel water and oil and protect surfaces against high temperatures; they’re now commonly found in items like nonstick pans, food packaging, and fire-suppressant foams, CBS reports. They’re called “forever chemicals” because they don’t appear to degrade, and are accumulating in our soil, water, and even our own bodies. 

According to Harvard’s School of Public Health, PFAS have been linked to some health issues, including cancer, liver damage, decreased fertility, and asthma. There are more than 4,000 of these chemicals in existence, and scientists are only beginning to grasp the health risks they may pose. 

The threat has led to a growing call for PFAS to be more tightly regulated: Last year, the Netherlands, Germany, Denmark, Sweden, and Norway submitted a proposal to the European Chemicals Agency to ban the use and production of forever chemicals. If passed, it’d be one of the broadest substance bans ever in Europe.

Where else are PFAS hiding?

A March 2023 study found that fish caught in rivers and lakes across the U.S. contained an alarming level of forever chemicals. These creatures were so contaminated that eating just one would be like drinking a month’s worth of polluted water, the researchers said.

PFAS are also being found, distressingly, in menstrual products. The popular period-underwear company Thinx settled a class action lawsuit last year for $4 million, after consumers accused the brand of selling reusable undies that contained PFAS and Agion, an anti-microbial coating that some say could be harmful to human health. And an independent analysis conducted by the watchdog site Mamavation and Environmental Health News, found the chemicals in 48 percent of pads and panty liners, 22 percent of tampons, and 65 period of period underwear, TIME reports.