Updated inventory for fluorspar (CaF2) and emissions of trifluoroacetic acid (TFA) from 1930, including the period from 2000 to 2020
The recently published updated inventory estimates global TFA emissions from all significant sources. It estimates emissions of anthropogenic TFA discharged to the Atlantic Ocean [1] and compares these to the estimated quantities of TFA measured in the Atlantic Ocean in 2022-2023 [2]. According to the paper, anthropogenic TFA is widely dispersed in the Atlantic Ocean, but the narrow body of water where relevant depth-profiles for TFA concentrations have been reported, covering a distance of about 13,300 km, a narrow corridor of 200 km, to a depth of 2000 m and 200 ng/L TFA, contains about 1 million tonnes of TFA. This is greater than the estimated anthropogenic TFA in the whole of the Atlantic Ocean. The paper concludes that the Atlantic Ocean must therefore contain a large natural burden of TFA. However, the mechanism of formation for naturally occurring TFA is yet to be determined.
The inventory paper explains that the publication of concentrations of TFA in the Atlantic Ocean, measured in 2022–2023 [2], is significant as the concentration measurements are extensive, including depth profiles in the North and South Atlantic Oceans, and allow an estimate of the burden of TFA in the Atlantic Ocean. The Atlantic Ocean, Caribbean Sea, and Mediterranean Sea and their drainage basins are used as the catchment area for discharges of anthropogenic TFA to water, and TFA in precipitation from atmospheric degradation of fluorocarbons, to estimate the quantity of anthropogenic TFA in the Atlantic Ocean. From 1930 to 2020, the reported anthropogenic contribution to TFA in the Atlantic Ocean is estimated to be 467,000 tonnes, with a theoretical upper limit of 1,215,000 tonnes. The inventory paper reports this is about 0.6% - 1.2% of the estimated 40-80 million tonnes burden of TFA in the Atlantic Ocean, and for the theoretical upper limit, 1.5% - 3% and that anthropogenic emissions are responsible for only a small fraction of the TFA observed in the Atlantic Ocean.
The paper states that due to their atmospheric lifetimes, HFCs, HCFCs, and anesthetics are dispersed globally, and generated TFA is deposited globally, allowing an estimate of the quantity deposited in the relevant oceans and seas, and their drainage basins. It explains that recent assessments of the use of pesticides and their formation of TFA on degradation have reported a TFA yield of 30% on average. These assessments allow an estimate of relevant pesticide use globally and generation of TFA, using a cropland area database to estimate global and regional pesticide use, and TFA discharge to the relevant drainage basins. An upper limit of TFA generation from pesticides is derived by assuming 100% TFA yield. TFA from other sources and their potential contribution to TFA in the Atlantic Ocean are estimated. The paper reports that increased emissions of TFA from sensitivity analyses or additional emissions in 2021 to 2022 are also estimated. Significant other industrial uses of fluorspar that could account for large additional emissions of TFA have not been identified, according to the paper.
[2] UBA (2024). Untersuchung von aktuellen Meerwasserproben auf Trifluoressigsäure (Investigation of current seawater samples for trifluoroacetic acid). https://www.umweltbundesamt.de/publikationen/untersuchung-von-aktuellen-meerwasserproben-auf#:~:text=Der%20Bericht%20beschreibt%20die%20Entwicklung%20und%20Validierung%20einer,aus%20den%20Jahren%202022%20und%202023%20zu%20bestimmen