Confronting the threat of TFA and other persistent and mobile substances to protect water resources

Water resources worldwide, even in remote locations, have become increasingly contaminated with substances that are considered persistent, mobile and toxic (PMT) or very persistent and very mobile (vPvM). This concern has recently led to PMT/vPvM substances being added a new category of hazardous substances the European regulation for Chemical, Labelling and Packaging (CLP, (EC) No 1272/2008) in 2023, as well as plans to add it to the REACH regulation (1907/2006/EC). PMT/vPvM substances are those which do not break down easily in the environment (persistent), are transported rapidly in the water cycle (mobile) and are in some cases toxic. They are associated with widespread, negative effects on the environment and human health, as well as with expensive clean-up costs. Advanced water treatment methods, like ozonolysis or activated carbon filtration, are generally ineffective. This has led to several civil and legal disputes regarding them, as it is not always clear who should pay for their large remediation costs. An exemplary case of a PMT/vPvM substance is trifluoroacetic acid (TFA). TFA is one of the ultrashort-chain perfluoroalkyl acids, a subset of the larger family of per- and polyfluoroalkyl substances (PFAS). TFA is a degradation product of many refrigerants, pesticides and pharmaceuticals and is also directly released from industrial products and processes; it is now widespread and increasing rapidly in water resources. TFA has been assumed to be of little concern, in part because it was not able to bioaccumulate; however, the ubiquitous accumulation in the environment, in particular its observed accumulation in water resources and in various plants, including crops, is causing concentrations in human blood to increase with time. Recent levels in many regions have exceeded recommended exposure thresholds. Concerns of TFA include liver toxicity, toxicity to reproduction and the slowing of respiration rates in microbial communities. This irreversible increase of TFA can be considered a planetary boundary threat, based on increasing exposure world-wide, irreversible environmental contamination, and long-lasting disruptive effects on human health and vital earth system processes. At the end of the presentation solutions will be provided on how diverse actors can work together to phase out the sources of TFA and other PMT/vPvM substances, on a pathway towards zero pollution. Keywords: water pollution, PMT substance, PFAS, TFA, transformation products. Acknowledgements: This work has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 101036756 - ZeroPM