Trifluoroacetate (TFA) in precipitation and surface waters in Switzerland
According to a paper by Henne et al. [1] sources and budgets of the persistent, anthropogenic compound trifluoroacetate (TFA) are poorly quantified across different environmental media. In their paper “Trifluoroacetate (TFA) in precipitation and surface waters in Switzerland: trends, source attribution, and budget” the authors present concentrations of TFA observed in precipitation and surface waters in Switzerland during three years of continuous monitoring and in archived water samples, collected since 1984. Simulated atmospheric degradation of known TFA precursors for 2021 - 2023 accounted for 63% (58 % - 70 %) of the observed deposition with 48% (41 %–54 %) due to hydrofluoro-olefins and 15% (12 % - 18 %) due to long-lived fluorinated gases. In Switzerland, atmospheric deposition of TFA amounted to 24.5 ± 9.6 tonnes/year, whereas TFA terrestrial inputs from the degradation of plant protection products (PPP) in soils, estimated from the literature, ranged from 2.9 to 11.8 tonnes/year, depending on the assumption on degradation efficiency. TFA inputs from the degradation of PPP dominated 2–3 times over atmospheric deposition in Swiss croplands. These inputs were balanced by exports through the major rivers, 31 ± 4 tonnes/year.
Henne et al. state in their conclusions that 29 % - 48 % of the observed atmospheric deposition was not explained by the simulated degradation of known precursor compounds. This gap may be associated with unknown precursor compounds, underestimated TFA yields from known precursors, model shortcomings or a combination of these. The authors comment that renewed scientific efforts are required to improve our understanding of atmospheric chemistry and fate of fluorinated compounds in the atmosphere as well as in soils and water bodies.
Henne et al. comment that the TFA yield of the main contributing long-lived fluorinated compound (HFC-134a) should be re-evaluated, since its currently accepted value of 7 %–20% is based on a small number of experiments conducted three decades ago [2] (Wallington et al., 1996). An annual average yield of 42% from HFC-134a (summer: 68 %; winter: 16 %) could explain most of observed gap and would be close to yields (37%) reported in earlier global chemistry simulations [3] (37% Kotamarthi et al., 1998).
However, it should be noted that the recent paper by Hart et al. (discussed in this newsletter) reported that the TFA molar yield for HFC-134a was calculated to be 9% [4].
References
[1] Henne, S., Storck, F. R., Wöhrnschimmel, H., Leuenberger, M., Vollmer, M. K., and Reimann, S., Trifluoroacetate (TFA) in precipitation and surface waters in Switzerland: trends, source attribution, and budget, Atmospheric Chemistry and Physics, 2025, 25, 18157–18186, https://doi.org/10.5194/acp-25-18157-2025.
[2] Wallington, T. J., Hurley, M. D., Fracheboud, J. M., Orlando, J. J., Tyndall, G. S., Sehested, J., Møgelberg, T. E., and Nielsen, O. J., Role of Excited CF3CFHO Radicals in the Atmospheric Chemistry of HFC-134a, The Journal of Physical Chemistry, 1996, 100, 18116–18122, https://doi.org/10.1021/jp9624764.
[3] Kotamarthi, V. R., Rodriguez, J. M., Ko, M. K. W., Tromp, T. K., Sze, N. D., and Prather, M. J., Trifluoroacetic acid from degradation of HCFCs and HFCs: A three-dimensional modeling study, Journal of Geophysical Research: Atmospheres, 1998, 103, 5747 - 5758, https://doi.org/10.1029/97JD02988.
[4] Hart, L., Hossaini, R., Wild, O., Mazzeo, A., Halsall, C., Hou, X., et al. Growth in Production and Environmental Deposition of Trifluoroacetic Acid Due To Long‐Lived CFC Replacements and Anesthetics, Geophysical Research Letters, 2026, https://doi.org/10.1029/2025GL119216