Chalk streams – a rare type of river that rises from springs in landscapes with chalk bedrock – are being impacted by microparticle pollution, according to a new study.
The ‘first-of-its-kind’ study by the University of Brighton and the Upper Itchen Restoration Community Interest Company (UIR CIC) on the River Itchen in Hampshire has found tiny plastic and fibreglass particles in its headwaters.
Citizen scientists from the local community, working with researchers, detected microfibre and microparticle pollution at every site sampled in spring 2025.
Microfibres – often shed from clothing – were prominent in the samples, while fibreglass, rarely reported in rivers, was also present, together with tyre particles from road run-off.
This sort of contamination can disrupt the river ecosystem, posing risks to insects, fish and mammals that depend on these chalk streams.
Early analysis as part of the study suggests this type of pollution is widespread across the streams of the Upper Itchen.
Finding microfibres and even fibreglass fragments at every site we sampled is concerning, but it also gives us the evidence we need to act.
Although particle size and colour varied, the results of the study found persistent, catchment-wide contamination.
They also confirmed that even chalk streams, which are renowned for their biodiversity, are being affected by particle pollution.
The research focused on identifying and quantifying pollutants in the Upper Itchen and is still ongoing. Additional samples are set to be analysed throughout 2025, with the aim of tracing pollution sources, assessing potential impacts on wildlife, and exploring ways to reduce harm.
The final report is expected later this year and aims to deliver the ‘first comprehensive picture’ of particle pollution in a UK chalk stream – around 200 of which exist worldwide, with most of them in the southern half of England and a few in France.
The project is led by Dr Corina Ciocan – Principal Lecturer at University of Brighton’s School of Applied Sciences and co-Director of the Centre for Environment and Society – and Ian Diver, a Director of the UIR CIC.
Commenting on the study, Dr Corina Ciocan said: “Chalk streams like the Itchen are unique and often compared to rainforests for their biodiversity. Finding microfibres and even fibreglass fragments at every site we sampled is concerning, but it also gives us the evidence we need to act.
“The next step is to identify the sources of this pollution and work with local partners to reduce it and mitigate the impacts.”