In 2019, nearly two dozen water agencies in Southern California were found to have reportable levels of cancer-causing chemical compounds in their wells. By 2020, 700 agencies with similar contamination had been identified across the United States. These compounds, known as perfluorinated alkylated substances or PFAS, are dubbed “forever chemicals” because, for a long time, there was no known way to break them down.
But Sharma Yamijala, a computational chemist at the University of California, Riverside, may have just discovered a solution. After hearing about the issue at a seminar in 2019, he got to work on the problem with two colleagues at the university. The results of their project were published in the journal Physical Chemistry Chemical Physics in January.
“I thought that we should try something out to understand what’s happening,” he tells OneZero.
Since the 1940s, PFAS have been used in a wide variety of products, like food packaging, nonstick pans, paints, cleaning supplies, and even smartphones. Because they don’t break down in the environment, they get into drinking water and other living organisms, many of which we eat. Since the body can’t digest them either, they accumulate inside of us, too.
“These pollutants are very persistent,” explains Bryan Wong, one of Yamijala’s co-authors on the paper, to OneZero. “They last for a long time.”
High levels of PFAS intake are linked to cancer as well as low birth weight and thyroid hormone disruption, according to the Environmental Protection Agency.
In his research, Yamijala used computer simulations to study the chemical structure of the PFAS that are the most ubiquitous in the environment: perfluorooctanoic acid and perfluorooctanesulfonic acid. The carbon-fluorine bond that acts as the backbone of these chemicals is one of the strongest bonds in organic chemistry, which is why they seem to last forever. But this is exactly what the team’s breakthrough addresses: When they exposed the compounds to excess electrons — a process called reduction — the bond with the fluorine atom broke.
What’s more, the broken molecules that resulted from the process had a domino effect on the remaining PFAS in the water. In the simulation, these smaller molecules accelerated the breaking down of the other PFA molecules.
“Scientists are the ones who helped the industrialists generate these chemicals in the first place.”
The results are promising, but more work must be done before the process can be used to decontaminate water in the real world, says Yamijala. For one thing, researchers must find out whether or not the new molecules created by breaking down PFAS are carcinogenic. Yamijala and his colleagues plan to run longer simulations to better understand these new molecules and how they function
Still, the breakthrough has potential to end the forever chemicals that have infiltrated water systems around the globe. Ideally, the method would be used at water treatment plants and aquifers. “You want to get rid of these chemicals before supplying water to households,” says Yamijala.
In the real world, the process would involve placing compounds that contain metal, like copper nanoparticles, into water and exposing them to ultraviolet radiation. Doing so would cause electrons to break off from the compounds, freeing them up to interact with the PFAS molecules and break them down.
Previous studies about the possibility of using reduction to break up PFAS suggested that doing so would be cost effective, says Yamijala. While there are still unknowns about costs in the real world — like that of the metal-containing compounds needed to break down the PFAS — research from the University of California, Los Angeles suggests the technique would cost 8 to 10 cents per liter of contaminated water to employ.
Though companies like DuPont, one of the largest corporations known to have used PFAS in its products, have phased out their use, the chemicals still continue to contaminate nearly every facet of our environment. Yamijala says scientists should play a role in cleaning up the mess, since they helped corporations create PFAS to begin with.
“It is scientists’ responsibility to show people how to break these bonds because scientists are the ones who helped the industrialists generate these chemicals in the first place,” he says.
“So scientists need to do the opposite, is what I believe.”