Establishing Evidence-Based Standards for PFAS Destruction Pathway Claims

Research on per- and polyfluoroalkyl substances (PFAS) destruction increasingly invokes claims regarding PFAS removal, defluorination, acceptable end points, and transformation pathways. However, the evidentiary basis supporting these claims remains inconsistently interpreted and often relies on indirect metrics that cannot support all forms of conclusion equally. In this Perspective, we propose a shared evidentiary ladder for PFAS destruction studies and show how it can be applied in two related but distinct ways: a practical evidentiary framework for treatment-relevant claims and a mechanistic evidentiary framework for pathway-relevant claims. Evidence is organized hierarchically from narrative inference and indirect metrics to partial product identification, mass balance closure, and direct mechanistic confirmation. By distinguishing what the same evidence base can support in treatment-oriented versus mechanism-oriented interpretation, this framework provides a basis for reducing overinterpretation, improving transparency, and strengthening comparability across PFAS destruction studies.