The global threat from the irreversible accumulation of trifluoroacetic acid (TFA)

Trifluoroacetic acid (TFA) is a persistent and mobile substance that has been increasing in concentrations within diverse environmental media, including rain, soils, human serum, plants, plant-based foods, and drinking water. Currently, TFA concentrations are orders of magnitude higher than those of other per- and polyfluoroalkyl substances (PFAS). This accumulation is due to many PFAS having TFA as a transformation product, including several fluorinated gases (F-gases), pesticides, pharmaceuticals and industrial chemicals, in addition to direct release of industrially produced TFA. Due to TFA’s extreme persistence and ongoing emissions, concentrations are increasing irreversibly. What remains less clear is the thresholds where irreversible effects on local or global scales occur. There are indications from mammalian toxicity studies that TFA is toxic to reproduction and that it exhibits liver toxicity. Ecotoxicity data are scarce, with most data for aquatic systems; fewer data are available for terrestrial plants, where TFA bioaccumulates most readily. Collectively, these trends imply that TFA meets the criteria of a planetary boundary threat for novel entities because of increasing planetary-scale exposure, where potential, irreversible disruptive impacts on vital earth system processes could occur. The rational response to this is to instigate binding actions to reduce emissions of TFA and its many precursors.