Polluting ‘forever chemicals’ build up differently across continents, finds study of global freshwater reservoirs

Ecosystems across the globe are increasingly threatened by contamination from per- and polyfluoroalkyl substances (PFAS), a group of more than 10,000 synthetic chemicals nicknamed ‘forever chemicals’ due to their persistence and mobility in the environment. PFAS are used extensively in many industrial and consumer applications and are released across the entire product lifecycle from manufacturing to disposal. Long-term exposure to these chemicals poses risks to human health and the environment.

In Europe, some PFAS are identified as substances of very high concern by the European Chemical Agency; the European Food Safety Authority, which has established guidelines for ‘tolerable’ weekly doses of PFAS in food; and as part of the Drinking Water Directive, which recently implemented rules on how Member States must monitor PFAS levels in drinking water in order to meet EU limits. Several of the most harmful PFAS substances have already been banned in the EU, with a REACH restriction covering all PFAS in fire-fighting foams and an on-going restriction process aiming to address other uses. The Chemicals Industry Action Plan (adopted in 2025) aims to support a transition away from PFAS where alternatives are available.

However, existing data on PFAS is limited, fragmented, inconsistent, and geographically uneven, say the authors of a new study, making it difficult to comprehensively understand how they are distributed and – crucially – where they come from. To address this knowledge gap, the researchers developed a new data-driven workflow to get a better picture of anionic PFAS occurrence in freshwater reservoirs across the globe. Anionic PFAS (containing a negatively charged atom) may be of particular concern in aquatic ecosystems, where they are highly mobile and show potential to bioaccumulate (build up and become concentrated within organisms over time).