The four-year national study, known as UNSaFE (UNderstanding the Scale, Sources, Fate and Effects of PFAS pollution), aims to understand how these toxic 'forever chemicals' spread, how they harm ecosystems, and how their risks can be reduced.
The initiative is led by scientists from Brunel University London, Imperial College London, King's College London, and the UK Centre for Ecology & Hydrology, with funding from UK Research and Innovation (UKRI).
They are joined by the Environment Agency and environmental charity Earthwatch, which will help engage thousands of volunteers to monitor PFAS in rivers, streams, and lakes across the country.
PFAS, or per- and polyfluoroalkyl substances, are a vast group of human-made chemicals used in everyday products such as non-stick cookware, waterproof jackets, food packaging, and firefighting foams.
These substances are celebrated for their durability - but that resilience makes them a serious environmental hazard.
Dubbed forever chemicals, PFAS do not break down naturally and can persist in the environment for decades. They accumulate in the bodies of fish, animals, and people, steadily moving up the food chain.
Exposure has been linked to liver and thyroid damage, immune system disruption, and potential reproductive issues in humans and wildlife.
Globally, scientists estimate that there could be more than 15,000 different PFAS chemicals, yet only a fraction - around 63 - have been detected and monitored.
In the UK, research has shown that over 90% of surface waters downstream from wastewater treatment plants exceed safety limits for at least one common PFAS compound, perfluorooctanoic acid (PFOA).
The UNSaFE project will provide the most comprehensive investigation yet into how PFAS enter and spread through UK waterways.
Researchers will focus initially on the Thames River Basin, collecting and analysing water, sediment, and biological samples to trace how these chemicals move through the environment.
Brunel University's team, led by Dr Thomas Miller, will specialise in examining how PFAS accumulate in aquatic life - from small invertebrates to fish - and determining which compounds pose the greatest danger.
The project will focus on 24 high-priority PFAS compounds currently regulated by the European Union.
The study will also employ cutting-edge techniques, including artificial intelligence and genomics, to understand how PFAS affect the biology of exposed organisms.
Researchers will develop new laboratory methods for detecting PFAS in water and wildlife, and set science-based safety thresholds to guide environmental protection policies.
To expand data collection beyond the Thames, Earthwatch will mobilise over 3,000 volunteers to test the quality of local rivers, streams, and lakes across the UK.
This citizen science effort will generate a nationwide picture of contamination and help communities play a direct role in safeguarding their waterways.
Scientists hope the UNSaFE project will give policymakers the clearest evidence yet to act decisively against PFAS pollution.
By understanding where and how these chemicals accumulate, and how they affect living organisms, the research aims to pave the way for stronger environmental regulations - protecting rivers, wildlife, and ultimately, human health.
As the investigation begins, the message is clear: tackling PFAS in rivers is not just about cleaning up pollution, it's about protecting the lifeblood of Britain's ecosystems for generations to come.