One of the toughest classes of pollutants are per- and polyfluoralkyl substances, or PFAS, as they are known. PFAS are often called “forever chemicals” because they are extremely long-lasting and difficult to clean up. They are found in household products including non-stick pans, dental floss, water-repellent fabrics, and many others. They can be found extensively in U.S. waterways and soil.
PFAS move through the food chain, accumulating in humans at levels that scientists say can cause adverse health effects. While these have not been definitively proven, there is evidence that higher cholesterol levels, cancer, thyroid disruption, and low infant birth rates are all associated with PFAS ingestion.
PFAS are difficult to get rid of because their carbon-fluorine covalent bonds are some of the strongest in organic chemistry. Researchers at Princeton University have been studying a process known as Feammox in which ammonium breaks down in acidic, iron-rich soils in New Jersey wetlands and similar locations. They found that this reaction takes place when a bacterium called Acidimicrobium A6 is present.
Using gene-sequencing techniques, they found that the microbe has characteristics that could help break down carbon-fluorine bonds, and therefore break down PFAS. In tests using microbe-loaded soil samples, they found that the bacterium removed 60% of PFAS pollutants within 60 days.
The research has been published in the journal Environmental Science and Technology and the team is now testing the bacterium’s effectiveness over different time-spans in lab conditions before testing it in the field.
Photo, posted November 9, 2017, courtesy of the Department of Environmental Quality via Flickr.