The 2019 film “Dark Waters” tells the real-world story of attorney Rob Bilott, who took on chemical giant DuPont for knowingly contaminating drinking water with toxic PFAS compounds. Specifically perfluorooctanoic acid, or PFOS, a substance used in the manufacturing of Teflon.
Through dramatized for the big screen, the proliferation of perfluoroalkyl and polyfluoroalkyl substances, or PFAS, is a very real problem, say scientists. The U.S. has identified nearly 12,000 PFAS chemicals, while Europe recognizes approximately 15,000. These substances, found in everyday products such as non-stick pans, waterproof clothing and sunscreens, are known for their persistence in the environment and the attendant health problems this causes.
Leading the fight against PFAS is chemistry professor Diana Aga and her team at the University at Buffalo, who are harnessing bacteria that can degrade these so-called “forever chemicals.” According to the study led by UB, certain microbes can break apart the super sticky carbon-fluorine bonds that give these compounds their nickname.
Photo: Meredith Forrest Kulwicki/University at BuffaloOver the course of their research, Aga and her colleagues have identified a bacteria strain that can neutralize at least three types of PFAS. The newly recognized Labrys portucalensis F11 bacteria also demonstrates an ability to break down harmful byproducts produced during the degradation process, said Aga.
“Because there are 12,000 of these chemicals, many of them remain unknown,” Aga said. “The exact structure of PFAS is unknown besides the bond between the carbon and fluorine atoms, which is very strong. The F11 bacterial strain has developed the ability to chop away the fluorine and eat the carbon.”
PFOS, a common environmental contaminant among PFAS chemicals, was designated as hazardous by the U.S. Environmental Protection Agency last year. In the lab at UB, F11 bacteria metabolized over 90% of PFOS after a 100-day exposure period. The microbe also broke down two additional PFAS types – fluorotelomer carboxylic acid (FTCA) and fluorotelomer sulfonate (FTS). FTCAs are used in stain repellents and food packaging, while FTS chemicals are most often found in fire-fighting foams.
“PFASs are really magical chemicals that have a lot of purposes and are used widely,” Aga said. “But when they end up in the environment, they become very dangerous.”
A broad impact
PFAS has been utilized across industries since the mid-20th century. Large-scale production of the chemicals occurred during the Manhattan Project – the U.S. effort to develop the atomic bomb – as a means to separate uranium. Their use soon expanded commercially, with companies like 3M hiring chemists who had worked on the bomb project.
Photo: Meredith Forrest Kulwicki/University at BuffaloScientists say the widespread application of PFAS has caused a similarly broad impact on humans, commonly entering the body through contaminated drinking water or crops fertilized with sludge. Researchers have linked even low levels of chronic PFAS exposure to health effects such as kidney cancer, thyroid disease and ulcerative colitis.
Current methods for eliminating PFAS, mostly involving intense heat or pressure, are expensive and often limited to the treatment of filtered waste. Aga’s team initiated their efforts against the chemical by isolating the F11 bacteria from a polluted industrial site in Portugal. Though the microbe had shown the ability to strip fluorine from pharmaceutical contaminants, it had never previously been tested on PFAS. UB’s analysis showed that the F11 bacteria could degrade some PFAS within a sealed-flask environment, said Aga.
UB scientists are not alone in studying the efficacy of bacteria on the man-made compound – prior studies demonstrated that the microbe Acidimicrobium sp. strain A6 is capable of breaking the ultra-tough carbon-fluorine bonds that hold PFAS chemicals together.
However, this slow-growing bacteria requires specific environmental conditions to flourish, a question that similarly hangs over UB’s research. Aga cautioned that F11 took 100 days to eliminate a significant portion of PFAS, in a setting that lacked other sources of consumption.
“We put (the bacteria) in optimum conditions to degrade PFAS, with nothing else to eat,” said Aga. “In the (outside) environment, F11 may have other ‘foods’ to degrade, and may ignore the PFAS.”
For the good of all
States including Ohio are working to understand the extent of PFAS proliferation. The Ohio EPA, in collaboration with the state department of health, has sampled 150 river locations and collected samples from sites where PFAS may be discharging into sanitary sewer networks.
While Ohio is not currently researching the use of bacteria for remediation purposes, it is providing loans to utilities to conduct PFAS evaluations, said press secretary Bryant Sommerville.
“Ohio is always interested in learning of new treatment and destruction technologies for PFAS,” Sommerville said in an email. “We continually meet with researchers and companies in those fields and encourage them to have conversations with our staff to discuss emerging technologies.”
Meanwhile, researchers continue to study bacteria that can completely metabolize PFAS, a goal complicated by the relatively short existence of the damaging chemicals. UB scientist Aga’s vision involves cultivating the F11 bacterial strain in wastewater treatment plant sludge, then directly injecting it into contaminated water and soil.
Ultimately, Aga sees the struggle against “forever chemicals” as essential to safeguarding future generations from toxicity and sickness.
“It’s become personal, because I know people with various cancers that may not be related to PFAS, but are coming from environmental exposure of all kinds,” said Aga. “I don’t want to be drinking water with PFAS, and I don’t want my friends and relatives getting cancer. People are doing (this research) not just for science, but for the good of society.”
