A New Way to Destroy Forever Chemicals

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are notoriously difficult to scrub from the environment. These so-called “forever chemicals” can take thousands of years to degrade naturally.

PFAS are used in a variety of consumer goods, including nonstick cookware, rain jackets, fast food packaging, and carpeting, due to their grease- and water-resistant properties. They leach into the environment during the production processes and seep through landfills. PFAS is everywhere—it contaminates drinking water, soil, and the air.

They’ve become so widespread that around 97% of people in the U.S. likely have PFAS in their blood. Over time, PFAS buildup can cause a range of health issues, such as low birth weight, reduced immune response, liver damage, high cholesterol, and various cancers.

Scientists now say that a simple combination of lye—a common ingredient in soap—and another common organic chemical could cause the chemicals to fall apart in a matter of hours. While the approach doesn’t work for all PFAS, it could become a cheap and safe way to reduce the toxicity of contaminated waterways, according to a new study published in Science.

Scientists have proposed other methods including incineration, oxidation, radiation, and even blasting contaminated water with cold plasma.

“Yes, you can destroy [PFAS]. But typically, the energy is so high that it’s really not economically feasible,” said Rainer Lohmann, PhD, director of a PFAS superfund research site at the University of Rhode Island Graduate School of Oceanography, who was not involved with the study.

The new approach is much less harsh: It’s a low-energy and cost-effective way to disintegrate the chemicals into relatively safe and natural compounds. “Their approach, of course, has the beauty of being much simpler,” Lohmann said.

How Would the New Approach Break Down PFAS?

Water filtration plants can remove PFAS from the water system with special filters, namely activated carbon and reverse osmosis technologies. Once these chemicals are filtered out, treatment sites are left with a potion of waste concentrated with PFAS. If the toxic chemicals are just tossed in a landfill, they will just leach back into the environment.

“There’s a need for a method to get rid of PFAS in a way that does not continue to pollute,” Brittany Trang, PhD, a coauthor of the new study and a reporting fellow at STAT News, said in a call with reporters.

This is where her team’s approach comes in. A simple chemical solvent could be added to these waste products so they could be disposed of safely.

The primary input is sodium hydroxide, also called lye, which is an inexpensive and well-known chemical commonly used in soap making.

The other chemical component of this process is called dimethyl sulfoxide (DMSO), another commonly used chemical compound. In this case, DMSO would never actually touch the drinking water that is being decontaminated.

“Nothing about this poses obvious environmental red flags or true deal breakers, especially when you couple that with the fact that you’re degrading these pollutants that otherwise will not degrade in the environment,” said William Dichtel, PhD, senior author on the study and professor of chemistry at Northwestern University.

PFAS molecules are made up of a string of carbon and fluorine atoms attached together, one of the strongest bonds ever created.

The researchers said the sodium hydroxide approach works specifically to break down carboxylates, which make up about 40% of PFAS. Not only did the process work on well-known carboxylic compounds like PFOA, but it could also degrade GenX, a PFAS substitute that’s often as damaging as PFAS.

Once the carboxylates disintegrate, fluoride is the only potentially toxic compound left. “Fluoride on its own is much less dangerous than any of the PFAS,” Lohmann said.

He emphasized that degrading carboxylates alone won’t solve the PFAS problem. Sulfonates, such as PFOS, which also make up 40% of PFAS, are even more challenging to break down.

Why We Won’t See This Implemented Right Away

Dichtel said the new finding helps researchers understand how carboxylic PFAS can break down and this can be a key step toward figuring out how to degrade other kinds of PFAS.

“I really think that the fundamental knowledge of how these materials degrade is probably the single most important thing coming out of this study,” Dichtel said. “Anyone working on PFAS degradation can look at this and have a better understanding of what might be going on in their process.”

In the long run, environmental advocates say that setting strict limits on—or outlawing—the production of PFAS by chemical manufacturers is the best way to reduce future contamination. In the meantime, scrubbing the existing PFAS from the environment can reduce health harms to communities with high exposure.

The approach may not be implemented right away. Researchers will need to run more tests in the laboratory and in the field. Then, it’s a matter of making it on the market.

“It’s a very good and strong study,” Lohmann said. “It’s a good step, but is this now the solution to our PFAS problems? I don’t think so. Not yet.”

“I’m not trying to say that the approaches that exist right now are really good. It’s just that water providers rely on them,” Lohmann said. “For them to switch, they really have to be convinced that the alternative is better and cheaper.”