MassDEP bench study finds limited PFAS mobilization risk from proposed thermal cleanup at Framingham site

Natalie Johnson of the Massachusetts Department of Environmental Protection presented a bench‑scale study showing that heating contaminated soil—an approach planned to remove dense nonaqueous‑phase liquids (DNAPL) at the General Chemical site in Framingham—accelerated transformation of some PFAS precursors but likely produced only a small increase in mobile perfluoroalkyl acids (PFAAs).

Johnson told advisory committee members the study was motivated by concern that remedial technologies targeting chlorinated solvents could "make things worse" for PFAS by converting currently immobile precursors into more mobile compounds. "Will my remedial technology potentially make things worse?" she asked at the session, framing the experiment's central question.

The bench test used six replicated glass reactors filled with Framingham soil and ran three at elevated temperatures (ramped up and held near 97 °C for 30 days) and three at room temperature. The team measured targeted PFAS by EPA method 1633, ran non‑target assays including a total oxidizable precursor (TOP) test and extractable organic fluorine (EOF) for soils, and captured vapors and condensate for…