The Interactions Between Bacterial Communities and PFAS

Over the past several days, LCGC International presented video clips from our interview with Ralph Mead and his team at the University of North Carolina, Wilmington, and the North Carolina PFAS Testing Network (1,2).

In part two of our conversation with Ralph Mead and his group, they discussed the challenges in characterizing and quantifying PFAS and environmental samples (2). In part three of this interview, they discussed the interactions between bacterial communities and replacement PFAS materials. Here's part three of our conversation with the Mead Group at UNC Wilmington.

Ralph Mead: There is literature out there that talks a lot about some of the precursor compounds that can be biologically degraded into a terminal product, typically a carboxylic acid, say PFOA or something like that. With replacement PFAS, there are still some unknowns about the lability of that compound when exposed to bacteria. We had a former postdoc, Jen, who did some biological degradation experiments looking at bacterial consortium changes over a six-month timeframe. We paired that with the quantitation of hexafluoropropylene oxide dimer acid (HFPO-DA), or the DuPont trade name (GenX), with time, and the results from the bacteria consortium indicate that there's a clear changing of the bacteria assemblages themselves, but the differences of GenX with time was not so clear cut. The picture was not quite as clear.

Paul Wojtal: So two of the things that I've been thinking about a lot are 1) the potential isotopic vaccination that occurs during biodegradation. So there's a larger question about asynchronic fractionation occurring during any sort of degradation of PFAS. And then there's a whole host of literature tracking the natural degradation of anthropogenic compounds using compound-specific isopropyl stress, and the capabilities of the method that we're building will hopefully lend itself to being able to answer some of these questions about both the speed at which these biodegradation reactions happen, but then also ensuring that they are actually proceeding by biological reactions and not some other mechanism.

This interview is part three of a six-part interview with Ralph Mead and his team. The links to Parts 1 and 2 can be found in the literature (1,2).

References

1. Wetzel, W. Inside the Laboratory: The Mead Group at UNC Wilmington and the North Carolina PFAS Testing Network. LCGC International. Available at: https://www.chromatographyonline.com/view/inside-the-laboratory-the-mead-group-at-unc-wilmington-and-the-north-carolina-pfas-testing-network (accessed 2025-04-04).
2. Wetzel, W. The Challenges of Characterizing PFAS in the Environment. LCGC International. Available at: https://www.chromatographyonline.com/view/the-challenges-of-characterizing-pfas-in-the-environment (accessed 2025-04-04).