While the Cape Fear region has often been termed “ground zero” for PFAS-specific contamination of drinking water, scientists on the West Coast are studying ways to break down the lasting chemicals.
READ MORE: Advocacy team urges UN to take action against PFAS pollution, citing human rights violation
PFAS, per- and polyfluoroalkyl substances, is an umbrella term for a family of at least 10,000 chemicals, both prized and detested for the same attribute — the inability to be easily destroyed.
Termed “forever chemicals” due to its unique characteristic that withstands environmental degradation, heat, and absorption, researchers are still learning ways to remove the contamination from groundwater, air, soil and food.
Scientists have found industrial uses of PFAS in more than 200 different applications, including fast-food containers, anti-staining fabrics and fire-suppressing foams.
A pair of engineering scientists at University of California Riverside recently released findings on two species of bacteria that dismantle certain versions of PFAS.
Associate professors in the Bourns College of Engineering, Yujie Men and Jinyong Liu, have been studying PFAS degradation methods since 2016. The most recent study, published in the journal Nature Water, was funded by the U.S. Department of Defense and National Institute of Environmental Health Science.
Men focuses on biological science and impacts, while Liu’s expertise is in chemical solutions.
Both have garnered attention for their studies on PFAS and solutions to destroying the stubborn pollutants plaguing the nation. As of June 2022, 2,858 locations in 50 U.S. states and two territories are known to be contaminated with PFAS, according to the Environmental Protection Agency.
Men discovered Desulfovibrio aminophilus and Sporomusa sphaeroides — naturally-occurring bacteria known to live in the ground — cut the PFAS’ chlorine-carbon bond. In turn, that starts a chain of reactions that destroy the structures, rendering PFAS compounds harmless.
“The microbes are universally found,” Men told Port City Daily on a call last week, “literally everywhere.”
As bacteria break down the carbon-chlorine bond, it replaces the released chlorine with oxygen. This makes the chemical unstable, Men explained.
“It will spontaneously break down further so it’s also cleaving its neighbors,” she said of the chain of atoms. “They will be less fluorinated, less chlorinated and less toxic.”
To truly understand the full health effect savings from the degradation, Men said she would have to consult a toxicologist.
A microbial approach to destroying PFAS saves energy and is inexpensive.
“Chlorinated PFAS are easier to disappear because their bonds are much weaker,” Liu said.
However, the solution would not apply to GenX, or other “legacy” PFAS, such as PFOA and PFOS, which are fluorinated compounds. The method only applies to chlorinated PFAS, used in various industrial, packaging and electronic applications. Teflon would fall into this category, as would water-repellent materials.
For a manufacturing or utility company to utilize the method — in the local case of Chemours or Cape Fear Public Utility Authority — the bacteria would be put in anaerobic bioreactors. The process would be similar to treatments commonly used in wastewater.
Chemours was not aware of the specific bacteria-destruction method but noted it has supported research into remediation techniques and evaluate developing treatment technologies.
For Men’s method, the bacteria itself would be “mined” out of the ground from common soil and isolated from the PFAS. For expedited cleanups, nutrients such as methanol could be injected into groundwater to promote bacterial growth. This would greatly increase the bacteria’s presence to destroy pollutants more effectively.
The Cape Fear River contains chlorinated versions of the chemicals. PFAS have been dumped into it for four decades — the cause of contamination is Chemours’ Fayetteville Works facility, a DuPont offshoot, located 70 miles upstream from Wilmington.
Though the bacteria method only affects chlorinated PFAS, Liu has been studying photochemical degradation that could apply to the legacy compounds and GenX. It’s a UV-based solution, using a specific type of light — a shorter wavelength than the average UV ray.
Both researchers said a combination of both modes of destruction may be the best solution — what Men calls “some harmony between degradation and chemical design.”
The one downside to Men’s method is it could hinder monitoring PFAS, prominent in the Tar Heel State. The North Carolina Department of Environmental Quality is leading the country on addressing PFAS contamination. It released its Action Strategy for PFAS last summer detailing future plans to include identifying health risks, developing science to set enforceable limits, and minimizing PFAS pollution.
While Men specifically pointed to the success of North Carolina’s monitoring program, she notes her findings could actually mean there are more chemicals than are being detected.
“If bacteria can eat chlorine containing PFAS so easily … maybe you can’t see them,” Men said. “The bacteria may have already eaten them.”
Jeff Warren, the executive director of the North Carolina Collaboratory — an academic research facility funded by the North Carolina General Assembly — said he’s always keeping an eye out for new studies, such as this one.
“If provided the resources, we would at least look to include this and other approaches to identify the best, or suite of best, technologies that truly do what researchers are hopeful they do — completely destroy PFAS,” he said. “But the Holy Grail has remained elusive thus far.”
Warren pointed to additional studies considered by the Collaboratory as well. In August 2022, a study published in the journal Science, reported a team of researchers mixed two inexpensive compounds — dimethyl sulfoxide and sodium hydroxide — and brought them to a low boil; within hours, the PFAS molecules fell apart.
The method could potentially be used to destroy the PFAS once removed from contaminated water or soil; it removes the carbon-oxygen “head” of the PFAS molecule chain, weakening the atoms.
According to the study, reported on by the New York Times, it’s been difficult for chemists to find “cheap and safe” methods to get rid of PFAS.
Warren’s goal would be to do a “Consumer Reports-style” analysis of a handful of technologies, specifically when looking into ways to destroy aqueous firefighting foams.
The state is working on a buyback program to collect PFAS-containing AFFF, used by fire departments to put out flammable liquid fires. Most departments report they do not use AFFF except in emergency situations, but there are limited alternatives at this time.
READ MORE: Local firefighters speak against becoming ‘human guinea pigs’ due to PFAS exposure
“We would not simply choose one single destruction technology to handle the old foam but rather test numerous reported technologies,” Warren said. “Actually have our science team measure and analyze output, air and liquid effluent, of any remediation to quantify and verify whether the PFAS are truly destroyed.”
While Men and Liu have made headway in their research, applying the method to a tangible, real-world form has many steps to go. Microbes have been used for biological cleanups of industrial pollutants for years, but using them to clean up PFAS is still “in its infancy,” the scientists say.
“There needs to be a technology transfer between the fundamental understanding and the industrial level — communication with the EPA and industry,” Liu said of next steps. “But that’s beyond our focus.”
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