Council of the European Union has formally adopted an updated list of pollutants affecting surface water and groundwater (17 February, Brussels), marking a significant development in EU water policy. The revised list of priority substances now includes additional pesticides, pharmaceuticals, and PFAS, while tightening environmental quality standards and strengthening monitoring obligations across Member States.

The update revises key pillars of EU water legislation, including the Water Framework Directive, the Groundwater Directive, and the Environmental Quality Standards Directive, aligning them with the latest scientific evidence. The European Parliament is expected to hold the final vote by the end of March.

Within MAR2PROTECT, this update aligns strongly with our mission to protect groundwater management. We interviewed Ana Pereiro, MAR2PROTECT Coordinator, to gather her perspective on the updated list and what it means for European water governance.

Science Must Drive the Lists

Ana Pereiro welcomes the scientific basis behind the new priority substances list:

“All the substances now being added are typically six-carbon chain and above. I fully agree with that. They are bioaccumulative, they are toxic.”

Her view reflects growing scientific consensus that longer-chain PFAS and similar persistent substances pose higher risks due to their ability to accumulate in organisms and ecosystems over time. However, she also stresses that regulatory lists must remain dynamic:

“I believe the lists should remove substances that have already been phased out or banned, and incorporate those for which there is clear scientific evidence — substances that are non-essential and have proven impacts on health and ecosystems.”

For Pereiro, regulation should not be static. Instead, it must continuously evolve as science advances.

The “Cocktail Effect”: More Than the Sum of Its Parts

A critical point raised in the interview is the so-called cocktail effect — the combined impact of multiple pollutants interacting together.

“The cocktail effect is much more powerful in landfill leachates than in an aquifer. Concentrations are higher because pollutants come from multiple products, and the complexity of the mixture increases the overall impact.”

This highlights a regulatory challenge: while individual substances may meet safety thresholds, their combined presence can amplify toxicity. This is especially relevant for complex waste streams and downstream aquatic environments.

The Case of TFA: A Persistent Gap

Ana also draws attention to trifluoroacetic acid (TFA), one of the most persistent PFAS-related compounds:

“TFA, which is highly persistent and known to have consequences for agriculture, and which travels through the entire water cycle — including via acid rain — is not included among the 20 substances listed in the Drinking Water Directive.”

She argues that TFA should be treated as a separate and specific case, given its extreme persistence and mobility. More broadly, she questions the limited scope of the Drinking Water Directive list and calls for stronger alignment across EU water directives:

“Different water directives — whether for human consumption, wastewater effluent, or river discharge — may require different concentration limits. But they should refer to updated and coherent contaminant lists based on scientific evidence.”

Are Member States Ready?

If the new rules are approved in March, are EU countries ready to implement them? According to Pereiro:

“All European countries are preparing, clearly. But there are major differences.”

She compares Europe with the United States, noting that regulatory limits for individual compounds are currently much stricter in the US:

“In the United States, the maximum limits for individual compounds are much lower than in Europe.”

This comparison suggests that while Europe is advancing, there is still room to strengthen standards further.

The Replacement Dilemma: Ban or Innovate?

Beyond regulation, the long-term solution raises deeper technological and economic questions. PFAS compounds are widely used because of their unique properties — chemical stability, water and grease resistance, and durability. Replacing them entirely may not be straightforward.

“Replacing these compounds is almost a utopia. Their properties are unique.”

Instead of assuming total elimination is immediately feasible, Pereiro advocates investment in safer alternatives:

“We need to invest — either in fluorine-free compounds that truly maintain the required properties and are proven non-toxic and non-bioaccumulative, or in inert PFAS that are scientifically demonstrated to be safe under controlled conditions.”

She emphasizes that innovation must focus not only on performance but on verified safety for both human health and the environment.