They’re everywhere. In the air you breathe, the water you drink, and the soil we grow our food in—decades of industrial and commercial production and use have left basically no corner of our lives untouched by PFAS (polyfluoroalkyl substances), commonly called ‘forever chemicals.’ The two most important things to know about these chemicals: They’re toxic, and they don’t degrade over time on their own. Instead, they accumulate in our environments and in our bodies.
But a newly discovered chemical mechanism could help in the fight against mounting PFAS pollution. Chemists have found a way to break down some types of these chemicals into harmless, component parts using inexpensive and common tools. The new research, published today in the journal Science, is a big step forward in our understanding of how these compounds react. And though we’re still a long way from solving the problem, we’re just a little bit closer to a healthier world.
Why PFAS Are So Dangerous?
PFAS are chemicals with a lot of different uses (food packaging, fire fighting foams, nonstick cookware, furniture, cosmetics, etc...). Their main draw is that they’re super good at repelling water, oil, and grease, and even at tamping out fires. They do all this by being super-duper non-reactive. PFAS are made up of highly stable molecules that basically just stick to themselves.
When they leach into the environment and enter our bodies, our systems have no way of getting rid of them. So, they pile up and cause problems. Research has found links between PFAS and multiple types of cancer, immune system problems, high cholesterol, liver disease, and issues with pregnancy and infant development. (Because of all these health effects, the EPA announced new limits on PFAS in drinking water in June, advising that safe water supplies should basically contain no detectable PFAS.)
Yet they’re very difficult, nigh impossible, to avoid. PFAS have been detected in drinking water across the U.S., both indoor and outdoor air, farm fields worldwide, fish, cosmetics, and elsewhere.
Even with lots of human effort, these forever chemicals have proven incredibly difficult to break down. Incineration doesn’t seem to work. Lots of strategies can lead to other toxic byproducts. And many methods can be cost-prohibitive, limited, or hard to scale up—like heating water containing PFAS to super high temperatures.
What’s New About This Method?
“It think it’s fair to say that all other emerging PFAS degradation methods are things that you would classify as very high energy [or] relatively exotic conditions,” said William Dichtel, a chemist at Northwestern University and one of the study researchers, in a press briefing on Tuesday. “That’s really what differentiates our finding from from from everything else that that’s out there,” he added— emphasizing the accessibility and relative ease of the new method.
Using just a little bit of heat and supplies that can be found in high school chemistry labs (sodium hydroxide, i.e. lye, and a solvent called DMSO), the researchers were able to take one type of concentrated PFAS and break it up into smaller, non-toxic compounds.
“Most chemists are taking two molecules and squishing them together to make one big molecule, like taking two Legos and putting them together,” explained Brittany Trang, who was the study’s lead researcher and completed her PhD at Northwestern University last month, in the press briefing. “But instead, what we were doing is smashing the Lego to bits and looking at what was left to figure out how it fell apart.”
And that second step is important. Not only did the chemists successfully degrade the PFAS, but they used quantum mechanical models to figure out exactly how it happened and to provide a road map for others to use in related research.
Which Diana Aga, an analytical chemist and PFAS researcher at the University of Buffalo who was uninvolved in the new study, told Gizmodo she was especially grateful for. “I appreciate everything that this publication has done in terms of detailed analysis and comprehensiveness.”
To smash the Legos apart, Trang and her co-researchers heated their PFAS, lye, and DMSO solution at temperatures between 80 and 120 degrees Celsius (176 and 248 Fahrenheit). After four hours, nearly 80% of the PFAS was gone, and after 12 hours, more than 90% of it disappeared—replaced by benign carbon byproducts like oxalate, which is in many of the vegetables we eat, or glycolic acid, which is commonly used in skincare products.
Characterizing those byproducts is a big deal as well, Aga said. It’s a thorough step that helps ensure more environmental harm won’t come from trying to tackle the issue (which has happened before with PFAS). “This study is beautiful, because they did that,” she added.
What Are the Limitations?
But even if it’s beautiful, the new research isn’t perfect. This isn’t the end of the PFAS problem or a quick-fix, the researchers all stressed.
For one, the method only works on some PFAS. There are over 5,000 unique PFAS compounds out there, and they come in different categories. Two of the biggest classes are known as carboxylates and sulfonates. The new method successfully got rid of almost all of the carboxylates in a solution, but it doesn’t work for the equally prevalent sulfonates (or any other PFAS types).
The researchers are hoping they or others could address this and expand to sulfonates in follow-up studies. “For now, this is not a general solution,” said Dichtel. “The biggest gap in what we have today versus what is needed is that we really would like to degrade sulfonates, as well.”
And it’s not as if the researchers can dump lye and DMSO into our water supply to get rid of PFAS there. “That would really not be good either,” Trang told Gizmodo in a phone call.
The potential use for this method is in degrading PFAS that have already been filtered out of drinking water. Lots of ongoing research is focusing on ways to do that, through activated charcoal or reverse osmosis. Once filtered out, a good destruction method is key to ensure the PFAS doesn’t just immediately leach back into the environment. Yet on its own, the new research doesn’t get rid of the pollution.
Other scientists, engineers, and lab groups have been working to solve the PFAS problem and have made some big strides recently. Earlier this year, a group of engineers published a method involving UV light, sulfite, and iodine that could be used to break down a broad array of PFAS. And some work has focused on using microbes to do the same. However, given the scale of the problem, we probably need every method and all the knowledge we can get.
“It’s not gonna save the world tomorrow, as much as I wish it would,” Trang told Gizmodo. But maybe it could help, for a day after that.