Trifluoroacetic acid (TFA) is an ultrashort-chain PFAS. While it has not gotten the attention of other PFAS “forever chemicals,” it is the subject of growing concern. Shorter-chain PFAS like TFA have been assumed to be less hazardous than longer-chain PFAS. Many scientists are now calling that assumption into question. In a recent CHE webinar, Dr. Hans Peter Arp shared a new study looking at the dangers of TFA.
TFA & the Montreal Protocol
Dr. Arp began his discussion with a look at the Montreal Protocol and James Lovelock. James Lovelock was the first person to devise a way to detect chlorofluorocarbons (CFCs) in the atmosphere. At the time, CFCs were commonly used as refrigerants and aerosols. Lovelock wrote that CFCs posed “no conceivable hazard.”
In the 1980’s, when scientists discover the hole in the ozone layer over Antarctica, the world learned that CFCs are actually very hazardous. In response, the Montreal Protocol phased out the use of CFCs. This intervention saved the ozone layer and averted disaster for life on Earth.
Since that time, the Montreal Protocol has gone through several revisions. The chemicals substituted for CFCs have been less ozone depleting but have been problematic for other reasons. Some refrigerants are not ozone depleting but are strong greenhouse gases. Some of the refrigerants in use now have less global warming potential but are significant sources of TFA. The accumulation of TFA in the environment has largely coincided with the increase in F-gas use following the Montreal Protocol.
Accumulating exposure
TFA is made intentionally but is also a degradation product. Sources of TFA include:
- Refrigerants and blowing agents (such as hydrofluorocarbons and F-gases)
- Agricultural chemicals (including fluenacet, oxyfluorfen, trifluralin, and fluometuron)
- Pharmaceuticals (including prozac, flecainide, and bicalutamide)
- PFAS production and products
- PFAS remediation (enhanced degradation techniques used to remove PFAS from water can lead to TFA formation)
There are no natural sources of TFA. Of all the PFAS in the environment, TFA is the most abundant. TFA exposure is so widespread that we are chronically exposed at levels higher than other PFAS. TFA is highly mobile and moves with the water cycle.
“It will go wherever the water flows.”
TFA can now be found in many plants, including crops. From Arctic ice cores to the leaves of trees, levels of TFA are increasing.
Human health effects: A growing concern
While the full effects of TFA on health are not yet known, early research suggests that there is cause for serious concern. Animal studies have shown TFA to have liver toxicity and indicate possible harmful impacts on the development of embryos in humans and mammals. In addition to concerns about human health, limited studies have found evidence for TFA toxicity to aquatic ecosystems and to soil and terrestrial systems.
As shown by the effects of CFCs on the ozone layer, the lack of understanding about harms does not equate to safety. The accumulation of TFA in the environment means that our exposure is continuously increasing.
As Dr. Arp noted, every organism is now exposed to TFA throughout its lifecycle:
“We do not have any data on what impact that has with such lifelong exposure.”
The study authors make the case that TFA poses a planetary boundary threat. Because TFA is so persistent and mobile, we cannot afford to wait until the health impacts are fully understood to take action.
What we can do
Dr. Arp stressed the need for binding actions to reduce emissions of TFA and its precursors. There are several steps we can take:
- Transition to PFAS-free and TFA-free alternatives, starting with the TFA precursors that are being produced in the greatest volume:
- Switch to alternatives to F-gases that are used as refrigerants and blowing agents.
- Phase out and restrict the use of PFAS.
- Phase out or find safer alternatives to TFA precursor pesticides and pharmaceuticals.
- Classify and label TFA as a PFAS. Regulate TFA like other PFAS.
- Remove TFA from active emission sources, ideally via the polluter pays principle.
For more on the threats posed by TFA and what we can do now, see our webinar Ultrashort-Chain PFAS: The global threat of trifluoroacetic acid.
This organizational blog was produced by CHE's Science Writer, Matt Lilley.