TRIFLUOROACETIC ACID FOUND IN BREAKDOWN OF F-GASES POSES NO RISK TO HUMAN HEALTH OR ENVIRONMENT

This assessment [1] by the Environmental Effects Assessment Panel (EEAP) of the United Nations Environment Programme (UNEP) provides the latest scientific update on a wide range of issues since their most recent comprehensive assessment (2018). It includes a comprehensive summary for Trifluoroacetic acid (TFA) and points out that most PFAS have different properties from TFA. Some HFCs and some HFOs breakdown produce TFA in the atmosphere. The summary has these important findings, but read the complete summary as it covers these issues in much greater detail:

• Trifluoroacetic acid continues to be found in the environment, including in remote regions, although not at concentrations likely to have adverse toxicological consequences.
  - Trifluoroacetic acid (TFA) is found in the environment as a salt, with a no-observed-effect-concentration (NOEC) for aquatic species, which is typically > 10,000 μg/L. TFA is produced by the environmental degradation of several hydrofluorocarbons (HFCs) and hydrofluoro-olefins (HFOs). Analysis of 1187 samples of rainwater collected in eight locations across Germany in 2018–2019 showed median and a precipitation-weighted mean concentration of TFA of 0.210 μg/L and 0.335 μg/L, respectively.
• Other sources of TFA, besides from refrigerants and propellants that fall under the purview of the Montreal Protocol, may be more important but less understood.
  - Fugitive emissions of TFA have been reported from landfills, transfer stations, and incinerators in locations where manufacturing facilities produce fluorinated chemicals.
• Current concentrations of TFA salts and related compounds in soil and surface waters do not present risks of adverse effects in aquatic and terrestrial plants and animals.
  - Historical and current measurements of TFA in soil and surface-water indicate de minimis risks when compared to no-effect-concentrations (NOECs) in laboratory and field-based testing.
• Humans could be exposed to TFA via drinking water and food but there is no evidence to date of adverse effects on health.
  - TFA salts are of low acute toxicity to mammals under conditions relevant to environmental exposure.

In its Summary Update 2020 for Policymakers [2], the UNEP Environmental Effects Assessment Panel has summarised these scientific conclusions for TFA: The current low concentration of trifluoroacetic acid (TFA) produced by the degradation of several hydrofluorocarbons (HFCs) and hydrofluoroolefins (HFOs), is currently judged not to pose a risk to human health or to the environment. Trifluoroacetic acid continues to be found in the environment, including in remote regions, although concentrations are currently very unlikely to have adverse toxicological consequences for humans and ecosystems [33,34]. While TFA is formed from the HFCs and HFOs regulated under the Montreal Protocol, a large amount of TFA was naturally formed over millions of years and has accumulated in the oceans. An unknown amount originates from fugitive emissions from chemical manufacture, waste disposal sites, laboratory use, and degradation of pharmaceuticals, pesticides, and industrial chemicals containing the trifluoromethyl group.

Notes:
[1] Neale, R. E., Barnes, P. W., Robson, T. M., Neale, P. J., Williamson, C. E., Zepp, R. G., et al. (2021). Environmental effects of stratospheric ozone depletion, UV radiation, and interactions with climate change: UNEP Environmental Effects Assessment Panel, Update 2020. Photochemical & Photobiological Sciences. https://doi.org/10.1007/s43630-020-00001-x. See sections 7.8 to 7.11 for Trifluoroacetic acid (TFA).
[2] available at Environmental Effects Assessment Panel (EEAP) | Ozone Secretariat (unep.org)