How to Get PFAS Out of Drinking Water—and Keep It Out

Filters in water pitchers or under-sink systems capture dangerous chemicals, only for them to be returned to the environment. A researcher from North Carolina is pioneering a new system that could get rid of forever chemicals forever.

There’s something scary in the water at Cape Fear. For years, chemicals giant DuPont and the company Chemours, which it spun off in 2015, manufactured long-lasting synthetic chemicals—known as forever chemicals—that made their way into the environment in this corner of North Carolina, ultimately ending up in the Cape Fear River. This is one of America’s PFAS hot spots, though forever chemicals are also found in tap water in thousands of locations around the US. (DuPont has been involved in several class action lawsuits across the United States related to the chemicals since the early 2000s.)

Specifically, DuPont and Chemours had used PFAS, or perfluoroalkyl and polyfluoroalkyl substances, for making Teflon, widely used in nonstick cookware. But, in the process, they contaminated the groundwater. Tests have shown that drinking water in this part of North Carolina can have levels of PFAS many times higher than the federal limit. The health effects of PFAS are frightening—from increasing your risk of cancer and obesity to lowering fertility.

“North Carolina’s still dealing with that,” says Jordan Poler, a chemistry professor at the University of North Carolina at Charlotte. “It’s a huge challenge for the people here.” Charlotte is more than 100 miles from the Cape Fear River, and the tap water there is fairly safe, says Poler. But hurricanes sometimes redistribute contaminated water in his direction. It’s partly what inspired him to come up with a new PFAS filtration system—and one with a key difference from existing systems.

“A lot of these media, you throw them in the landfill and they’re just going to leach everything back out,” he says of the short-lived filters people often use in pitcher devices or fitted to pipes under their kitchen sinks. Poler wanted to be able to suck PFAS back out of the filter and dispose of it safely instead. He has come up with a low-cost, reusable filter that he’s racing to bring to market. “I’m working my butt off,” he says.

In less than a hundred years since their invention in 1934, humanity has bestrewn planet Earth with PFAS chemicals. Manufacturers have stuffed them into cleaning fluids, frying pans, and clothes, among other products. Now, practically anywhere you look, you’ll find traces of PFAS littering the environment. From Mount Everest to Antarctic Penguins and, probably, your tap water.

A recent newspaper investigation revealed that PFAS chemicals are in some drinking water supplies in England, while the authors of a separate 2023 study estimated that 45 percent of private and public US drinking water was contaminated by one PFAS chemical or more. The Environmental Protection Agency suggests that between 6 percent and 10 percent of US public drinking water systems are affected.

The US banned a handful of particularly harmful PFAS chemicals from drinking water last year, but some water-watchers are already worried that the new Trump administration could roll back these protections. Plus, just last month, a major new research paper described how people living in parts of the US with high levels of PFAS in the drinking water were already more likely to have certain cancers, including oral, lung, and brain cancer.

“These are compounds that don’t break down in the environment, at least not on timescales that are relevant to humans,” says Colin Cooke at the University of Alberta. “We’re stuck with them.”

It’s the ultra-strong carbon-fluorine bonds in PFAS molecules that make them so long-lived. These chemical bonds are among the strongest ever recorded. Cooke explains that PFAS chemicals effortlessly move around with the water cycle, which is how they end up all over the place: “Anywhere that the wind blows and the rain falls, there is potential for these contaminants to be introduced to the environment.”

There are three main ways of removing PFAS from water—reverse osmosis, activated carbon filtration, and ion exchange. Reverse osmosis involves forcing water through a semipermeable membrane, which encourages contaminants to separate out from the water. Activated carbon, meanwhile, adsorbs contaminants as water passes through the filter.

Poler has opted for the third type with his filter—ion exchange. In this version, the water passes through a fine sand-like material that chemically attracts and filters out certain contaminants. “We use sustainable materials,” he says. “It’s a natural zeolite [mineral]. You can dig it out of the ground; you don’t have to spend energy making it.”

On a microscopic level, Poler says this material has a complex shape. He describes it as a pile of tiny sticks, between which water molecules may pass. That means there’s a high surface area for attracting and pulling out the nasty stuff. Once the filter is full of PFAS and other unwanted materials, Poler says he can regenerate it by using a special fluid to chemically attract those contaminants out. “I’ve done hundreds of cycles; there’s no performance degradation,” he says. He and some colleagues published a study describing the principles of their approach in 2023.

The recovered PFAS would ideally then be sent for processing, to once and for all break those carbon-fluorine bonds and dispose of the material safely. Poler has identified companies in North Carolina that he says could do this. The process would require energy to heat and pressurize the PFAS. The alternative, Poler says, is to risk those compounds returning to the environment again—perpetuating the toxic cycle. He adds that he hopes to see his filter on the market as early as later this year. Some other companies advocate instead for long-term containment or storage of PFAS materials underground.

In total, there are more than 10,000 PFAS chemicals out there, though some are considered especially harmful. Two in particular, PFOA and PFOS, are so dangerous that they have already been banned from products in a number of countries, including the US. Despite this, other harmful PFAS molecules still turn up in a shocking range of consumer goods, according to Tasha Stoiber, senior scientist at Environmental Working Group, a nonprofit. “Even cosmetics,” she says.

Practically everyone now has PFAS in their body, adds Stoiber. But your risk of exposure varies depending on where you live. Military bases and their vicinities are notorious hot spots, generally because of the PFAS in foams used to put out jet fires.

Stoiber and her colleagues at EWG keep an eye on the consumer-grade water filtration systems available in the US. The organization’s tests have found that common pitcher filters from brands such as Brita and Berkey do not all remove PFAS equally well. But some do an excellent job, based on EWG’s tests, including the pitcher filter system made by Epic Water Filters, a US-based firm.

“I would say PFAS is by far the number one contaminant that we’re getting feedback for our customers being worried about,” says Joel Stevens, cofounder of Epic Water Filters. The filters his company makes for its water pitchers include a carbon block. “Thousands upon thousands of layers of carbon fibers that are wrapped around a block,” he explains. As the water trickles through those fibers, the carbon takes off PFAS and other contaminants, including chlorine and lead.

In about three months’ time, the company will launch a new pitcher filter that can also take out heavy metals and fluoride. Fluoride is added to water in some areas in order to improve dental health, though some people would prefer not to drink it because of a potential link between fluoride and adverse neurological effects. Scientific analysis suggests that the risk from tap water in countries such as the US, however, is extremely low.

While there are some very effective water filter products on the market, says Stoiber, many people still throw spent filters in the trash, which means they ultimately end up at landfill sites where the PFAS can leach out into the environment again.

Customers of Epic Water Filters can return their spent filters to the company. “The filters are then sent to a special recycling center where the plastic is recycled and the internal filters are incinerated,” says Stevens in a follow-up email.

Stoiber’s research suggests that some forms of incineration of PFAS materials can release harmful compounds into the environment. “We still don’t have good disposal recommendations for spent treatment media,” she says. It is possible to break PFAS compounds down, though, at extremely high temperatures, even as high as 1,500 degrees Celsius (2,730 F). Some researchers are currently exploring how chemical additives such as granular activated carbon could reduce the amount of heat required to break down PFAS compounds.

There’s another problem with current approaches to PFAS. “Community-level drinking water treatment is what’s needed at this point, because the costs shouldn’t fall on the individual,” says Stoiber. “It shouldn’t be unfair, who has a filter, who doesn’t, who gets exposed.”

While some US drinking water facilities are now installing large-scale PFAS filtration technology, such as in Tampa, Florida, the cost of doing this across the nation could spiral into the billions, according to some analyses. While Stoiber says the most effective strategy for avoiding PFAS contamination is not to use these chemicals in the first place, countless companies still do, and it could be a long time before they disappear entirely from consumer products, if that ever happens.

For now, there is a risk that the Trump administration could weaken the new US water regulations that demand the removal of some PFAS molecules from tap water supplies, says Stoiber. “We are fighting to protect the drinking water laws that were just passed,” she says. “I think all eyes are on that.”

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