Tackling the Problem of Forever Chemicals

_ The legacy of per- and polyfluoroalkyl substances (PFAS) is a persistent problem in many industries, including upstream oil and gas. In this Q&A, remediation expert Grant Scott, SPE, presents the trouble with these “forever chemicals” and the mitigating efforts being used. Scott is principal consultant and co-founder of Ambio Holdings, an Australian environmental technology business developing source-control solutions for PFAS-affected infrastructure, soils, and materials. He holds a BS degree in physics from Washington State University, an MS degree in petroleum engineering from The University of Texas at Austin, and a JD degree from The University of Melbourne. Scott has been a member of SPE since 1982. JPT: What are PFAS, how are they used, and why are they a problem? Scott: Per- and polyfluoroalkyl substances (PFAS) are a family of several thousand synthetic chemicals built around a chain of carbon atoms fully or partly bonded to fluorine. That carbon/fluorine bond is the strongest single bond in organic chemistry, which is exactly why industry loves them and why the environment can’t get rid of them. They repel water and oil, survive heat and solvents, and lower surface tension better than almost anything else, so they’ve gone into firefighting foams, nonstick and stain-resistant coatings, fluoropolymer seals and linings, hydraulic fluids, electroplating, semiconductors, and textiles since the 1950s. The problem is threefold. They don’t break down under normal environmental conditions. They’re mobile; the short-chain and anionic forms move readily with groundwater and travel kilometers from source. And they bioaccumulate. In 2023, the World Health Organization’s cancer agency classified perfluorooctanoic acid (PFOA) as a Group 1 human carcinogen, the same category as asbestos and benzene, with kidney and testicular cancer the strongest associations, and perfluorooctanesulfonic acid (PFOS) as possibly carcinogenic. The US Environmental Protection Agency (EPA) rates both as likely human carcinogens and set the health goal for PFOA at zero, meaning no exposure level is considered safe. Beyond cancer, the established effects include immune suppression, raised cholesterol, liver damage, thyroid disruption, and reduced birth weight. PFOS and PFOA now sit on the Stockholm Convention’s list of persistent organic pollutants alongside the original “dirty dozen,” including dieldrin, DDT, PCBs, and dioxins, chemicals we spent the 1980s and 1990s pulling out of the ground. The difference is that those were mostly banned during my early career; PFAS were still going into fire-training grounds and fracturing fluids a decade ago. Regulators are now setting drinking-water limits in the low parts-per-trillion range. Australia’s 2025 guideline for PFOS is 8 ng/L. Thirty years ago, we were designing to milligram-per-liter criteria for hydrocarbons. We are now regulating a contaminant six orders of magnitude lower, for which conventional remediation largely doesn’t work.