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- Scientists from Brown University, the University of Minnesota, and the U.S. Navy found that injecting colloidal carbon into contaminated soil can trap PFAS chemicals underground, dramatically reducing contamination.
- In field tests, PFAS concentrations fell from over 50,000 nanograms per liter to undetectable levels within 10 months, capturing both long- and short-chain PFAS compounds.
- The approach could cost less than half as much as current cleanup methods and require minimal maintenance, offering a sustainable solution for communities dealing with PFAS pollution.
Over decades, per- and polyfluoroalkyl substances (PFAS) have slowly woven their way into our daily lives, without most of us ever noticing. They’re the stuff that prevents your eggs from sticking to the frying pan, waterproofs your jackets, allows makeup to last an entire day, and keeps those fast-food wrappers grease-resistant.
They’re also the stuff that earned the unsettling nickname “forever chemicals” thanks to carbon-fluorine bonds so strong that once these chemicals enter the environment, they tend to stay there. Forever. And that durability has become a serious problem. Scientists are increasingly recognizing that PFAS may cause a range of health issues, even as these chemicals have been detected in groundwater near military bases, airports, industrial sites, and municipal water systems across the United States. Cleaning them up has proven frustratingly difficult, expensive, and often temporary. Public-facing advice has often focused on avoiding products that contain PFAS or relying on above-ground water filtration, which requires almost constant upkeep. But now a few savvy researchers say they may soon have a solution for that, too.
Researchers from Brown University and the University of Minnesota, alongside industry partners and the U.S. Navy, tested whether an ultrafine carbon material could be injected directly into contaminated soil to trap PFAS in place. Their findings, published in The Journal of Hazardous Materials, show that it may be a wild enough idea to work.
The team tested an activated carbon material known as “colloidal carbon,” which acts like a microscopic sponge that can trap PFAS chemicals underground. They began by trialing it in lab conditions, collecting soil from a contaminated site, before testing it on the real thing, taking it to a field at a Navy training area known to have extremely high PFAS levels.
The researchers ran a “push-pull” test, injecting the carbon into the ground, creating an underground treatment zone where PFAS bind as groundwater flows through the net, then pumping the water back out to measure how much of the PFAS made it through. In their tests, the PFAS concentrations dropped from more than 50,000 nanograms per liter to tktk, below detection limits, within 10 months. Importantly, the carbon net captures both long-chain and short-chain PFAS. This is a big deal for the potential cleanup of these forever chemicals because short-chain PFAS are harder to remove, yet are becoming increasingly common as manufacturers move away from older compounds.
Just as important from an economic standpoint is that, according to the team’s analysis, the long-term operating costs of this carbon-based approach would be less than half those of the existing PFAS remedies. And because the system would exist underground, it would require little maintenance.
“This study shows that we can create an effective treatment zone underground that dramatically reduces PFAS levels with far lower long-term costs,” Matt Simcik, a professor in the School of Public Health and co-author of the study, shared in a statement. “The effectiveness of this method, combined with the fact that the system requires very little ongoing maintenance, makes this a promising option for real-world cleanup efforts. For communities facing PFAS contamination, this represents a major step forward toward practical, sustainable technologies that can protect drinking water and reduce long-term exposure risks.”
It’s critical to note that this isn’t a silver bullet — at least not yet. The researchers are clear that more work is needed to understand how long underground carbon remains effective and how it could perform under different soil conditions. But the study does offer some good news and a potentially practical path forward in the fight against forever chemicals. And, on a similarly impactful note, it shows just how important it is that we work on this issue together.
”The project shows the importance of partnerships between practitioners, government, and academia,” William Arnold, a professor in the College of Science and Engineering, said. “The expertise, experience, and insight of the individuals who made up the team were needed for this lab-to-field project to succeed.”
