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Rivers across all four nations of the UK are contaminated with a type of per- and polyfluoroalkyl substance (PFAS), according to a new study.
Researchers from York University and the environmental charity Fidra sampled water from 32 rivers across England, Wales, Scotland and Northen Ireland.
The majority of samples taken from the rivers (31 out of 32) tested positive for the short-chain PFAS trifluoroacetic acid (TFA).
Only the River Ness in Scotland was free of this troubling chemical, which is known to cause birth defects in animals.
TFA in water
Like all PFASs, TFA is considered a “forever chemical” as it doesn’t naturally break down.
It’s thought to be one of the most abundant PFASs in the world, as it is typically produced from the breakdown of larger PFASs found in environmental contaminants like pesticides and pharmaceuticals.
What are PFASs?
Forever chemicals were first mass-produced in the mid-20th century as waterproofing agents for commercial products like pans, packaging and raincoats.
Academic understanding of the compounds eventually began to build in the 1990s, following decades of gatekeeping and lobbying from the chemicals’ two prime producers, 3M and Dupont.
Once this research got going, it became apparent that the chemicals had spread to every corner of the planet, were practically unbreakable and, in significant doses, could cause cancer and birth defects.
To gauge how present TFA is in UK rivers, the researchers from the University of York and Fidra took 214 water samples from 54 sites across 32 rivers. Nine locations were chosen in Northern Ireland, 19 in Scotland, 21 in England and 5 in Wales.
Following high-performance liquid chromatography-tandem mass spectrometry (HP-LC-MS) analysis, TFA was detected in 167 of the 214 samples (an overall detection frequency of 78%) and in 53 of the 54 sites (a site-level detection frequency of 98%).
Most regions had an average concentration in the hundreds of nanogram per liter (328 ng/L, 183 ng/L, etc.).
The Scotland Glasgow region, however, had a whopping 23,968 ng/L average TFA concentration. The most contaminated sample – obtained from the River Kelvin in Glasgow in the winter of 2023 – had a concentration of 78,464 ng/L, making it the second highest maximum concentration ever reported, only exceeded by a river monitoring study in Germany.
“The Glasgow data are intriguing and we aren’t sure why they are so high,” Alistair Boxall, a professor of environmental science at the University of York, told Technology Networks.
“I initially thought it might be a one off, but we saw high concentrations across the seasons and in different rivers in the area.”
“There were other locations that had fairly high levels compared to other studies, such as the River Foss in North Yorkshire,” Boxall added. “They tended to be areas where the land use was dominated by arable agriculture.”
The lowest mean TFA concentration, 102 ng/L, was recorded in the South Wales region.
Only one river, the River Ness in Scotland, didn’t show any signs of TFA contamination.
Overall, the average TFA concentration in all UK rivers stood at 2,211 ng/L – a figure higher than the European average of 1,220 ng/L.
Boxwell and his colleagues say further work will be needed to analyze regions not covered in their study (such as the south of England).
“Moving forward, these data should be further analyzed to try and establish the drivers of TFA contamination in UK surface waters and routes for source control should be prioritized,” their report concluded.
Reference: Li J, Boxall ABA, Swan C, et al. Concentrations of trifluoroacetic acid (TFA) in UK surface waters. Fidra. Preprint posted online June 12, 2025. Accessed June 17, 2025. Doi: fidra.org.uk/download/concentrations-of-trifluoroacetic-acid-tfa-in-uk-surface-waters/
About the interviewee:
Alistair Boxall is a professor of environmental science at the University of York. His research focuses on understanding emerging and future ecological and health risks posed by chemical contaminants in the natural environment.
This article is based on research findings that are yet to be peer-reviewed. Results are therefore regarded as preliminary and should be interpreted as such. Find out about the role of the peer review process in research here. For further information, please contact the cited source.
