What is TFA?
TFA or trifluoroacetic acid is a very short-chain perfluorinated substance (PFAS).
TFA is used in many industrial applications (it is a strong acid) and to produce fluorinated molecules.
TFA can be found in various environmental elements (water, air, soil, etc.) as a result of:
• its direct release into the environment;
• the degradation of several thousand PFAS released into the environment, including fluorinated gases present in the atmosphere and fluorinated pesticides used in agriculture.
Why worry about TFA?
According to some studies, TFA's high mobility and persistence mean that it is present everywhere in the environment.
To date, there are no health recommendations based on exposure levels, nor are there any regional, national or even European regulations governing water intended for human consumption.
To understand the situation in Wallonia, it is first necessary to have a comprehensive overview of the TFA content in water intended for human consumption.
Is there a standard for TFA in tap water?
There is currently no legal limit for TFA in surface water or groundwater, either at the regional, national, or even European level.
In a statement dated August 7, 2024, the European Commission clarified that the health effects of TFA are currently being evaluated by the WHO (World Health Organization), based on the most recent scientific knowledge. Depending on the outcome of this evaluation, the WHO may issue recommendations regarding TFA concentrations in drinking water.
What is the TFA content of tap water in Wallonia?
At the request of the Walloon government, SWDE coordinated a sampling and analysis campaign to assess the presence or absence of TFA in the drinking water supply across the entire Walloon region.
The results of this regional monitoring are available online on the website of the Public Service of Wallonia (Service Public de Wallonie).
According to the opinion provided by the Independent Scientific Council on PFAS (CSI), consulted by the Walloon government, these results do not call into question the potability of the water.
Indeed, the PFAS CSI “unanimously proposes using a guideline value of 2,200 ng/L of TFA in the Walloon drinking water network, provided that only TFA is present in the water sample in question.”
The maximum limit of 100 ng/L for the sum of the 20 PFAS remains applicable alongside this recommendation for TFA. The indicative value for TFA in drinking water proposed by the CSI thus serves as a consultative reference that may be used by the competent authority (SPW-ARNE). Exceeding this guideline value does not compromise the potability of the water but requires an enhanced monitoring plan to identify and eliminate the source of TFA contamination.
On October 17, 2024, the Walloon Government adopted this guideline value of 2,200 ng/L for TFA.
How is TFA detected in water intended for human consumption?
Detecting TFA in water intended for human consumption requires sensitive and specific analytical techniques due to the low concentrations at which it may be present.
HPLC-MS/MS is the preferred technique for detecting the presence of TFA in water. It combines the separation of TFA from other molecules present in the water by high-performance liquid chromatography (HPLC) and detection by tandem mass spectrometry (MS/MS) for a highly sensitive and specific measurement.
How is TFA eliminated from water intended for human consumption?
Conventional techniques used to treat tap water (such as chlorination or filtration) are not effective in removing TFA. It is necessary to use more advanced techniques such as reverse osmosis. This expensive technology consumes energy and water. In addition, managing the TFA concentrate removed from the water raises environmental issues.