The government of Wallonia – the French-speaking southern region of Belgium – disclosed on October 17 preliminary results on the presence of trifluoroacetic acid (TFA) in drinking water, finding TFA in in 598 out of 642 distribution zones (93%), including 13 in which the 2.2mcg/L guidance value was exceeded.

TFA, an ultrashort-chain member of the PFAS (per- and polyfluoroalkyl substances) category, is produced in the environment from the breakdown of certain HFOs (particularly HFO-1234yf) in the atmosphere, pesticides and pharmaceuticals and from sewage treatment and industrial pollution. Known as “forever chemicals” for their durability in nature, PFAS, have been linked to cancer and other conditions; the health impact of TFA is still being assessed, though the German government has linked it to reproductive toxicity.

Despite the findings, the Walloon government indicated that “everywhere in Wallonia, tap water is safe to drink.” The government also endorsed “continued monitoring of the areas and the identification of sources of TFA in raw water,” adding, “This work is part of the regional strategy to combat PFAS in the environment.”

“I reaffirm here Wallonia’s commitment to protecting public health and maintaining a high level of transparency in the management of PFAS,” said Yves Coppieters, Minister of Health and the Environment for Wallonia. “We act with determination to monitor quality of distribution water, and we take all necessary measures to limit the impact of these substances on the environment and the health of our citizens.”

At the request of the Walloon government, the Walloon Water Company (SWDE), which produces and distributes drinking water in the region, measured the presence of TFA at the tap in the 642 water distribution zones in June and July of this year. The results are available here. In 13 zones, the TFA level exceeded 2.2mcg/L, a guidance value for drinking water (if only TFA is present) set by the Independent Scientific Council (CSI) PFAS in Wallonia. The 13 zones encompass more than 100,000 residents. The highest level (3.1mcg/L) was detected in the city of Philippeville.

Another zone, in the city of Ciney, which conducted its own survey, also showed high levels (2.4mcg/L), according to an article in RTBF Actus.

The 2.2mcg/L drinking water limit for TFA, which is also used by the Netherlands, is intended to serve as “an advisory value” that can be used by the Walloon environmental ministry (SPW-ARNE). “Exceeding this guideline value does not call into question the potability of the water but requires an increased monitoring plan to identify the source of TFA contamination and to eliminate it,” said the Walloon government.

The EU’s Drinking Water Directive (DWD), which will take effect January, 12, 2026, establishes limits of 0.5mcg/L for “PFAS Total” (all PFAS, including TFA) and 0.1mcg/L for the “Sum of PFAS,” which covers a list of 20 PFAS (not including TFA). The Walloon government referred to the latter limit as remaining “applicable” along with its recommended 2.2mcg/L drinking water limit for TFA.

Another article in RTBF Actus noted that in 240 out of the 642 zones, or 37%, TFA levels exceeded the future European PFAS Total directive of 0.5mcg/L, which the Walloon government plans to implement in 2025, ahead of the EU’s 2026 date.

The European Commission recommends that in the analysis of PFAS Total, the contribution of TFA in water intended for human consumption should be separately evaluated as the TFA concentration could significantly exceed 0.5mcg/L.

Additional checks

The Walloon government added that it plans to do “additional checks” in 36 distribution zones where the TFA concentration exceeded 1.5mcg/L. The government said it will also “improve transparency and communication” with the municipalities concerned. In addition, the SPW-ARNE will be responsible for communicating a “reassessment of the situation” based on TFA evaluations being conducted by the World Health Organization (WHO). According to the EU, the health effects of TFA are being assessed by the WHO on the basis of the most recent scientific knowledge. Depending on the results of this assessment, the WHO could issue new recommendations regarding TFA concentrations in drinking water.

The widespread presence of TFA in drinking water could represent a major challenge for water distributors because conventional activated carbon filters are unable to capture this ultra-short chain PFAS. Only reverse osmosis works, but this process is expensive.

Reacting to the detection of TFA in European waterways, the NGO Nature & Progrès called for “a rapid, global political response to ensure our waters remain healthy for the future,” adding, “this includes, first and foremost, stopping the sources of TFA pollution in our waters upstream, i.e. banning PFAS pesticides and fluorinated gases.” In May, Nature & Progrès, PAN Europe and other European organizations released a report on TFA in European surface water, followed by a July report on TFA in European drinking water.

Meanwhile in the country of Luxembourg, which borders southeastern Wallonia, Paul Galles, President of the Environmental Commission, acknowledged the urgency of the TFA issue, according to an article in RTL Today. “We don’t yet have a specific limit, but we do have a reference value, which is set at 12,000 nanograms per liter [12mcg/L]. Currently, based on the measurements we have, the levels in drinking water, groundwater, and surface water are far below this. So, there is no immediate danger. However, it is known that the risk could increase because TFA is present in many products we use in our daily lives.”

According to the Luxembourgish Ministry of the Environment, TFA levels in Luxembourg’s drinking water, measured since last year, have reached up to 0.9mcg/L.

The chemical industry addressed the environmental deposition of TFA in an October 2021 study funded by the Global Forum for Advanced Climate Technologies (globalFACT), which represents f-gas producers Chemours, Honeywell, Arkema and Koura (and equipment manufacturer Daikin). The study concluded that “with the current knowledge of the effects of TFA on humans and ecosystems, the projected emissions through 2040 would not be detrimental.” But the study also acknowledged that “the major uncertainty in the knowledge of the TFA concentrations and their spatial distributions is due to uncertainties in the future projected emissions.”

“We act with determination to monitor quality of distribution water, and we take all necessary measures to limit the impact of these substances on the environment and the health of our citizens.”

Yves Coppieters, Minister of Health and the Environment for Wallonia