Early analysis suggests this type of pollution is widespread across the streams of the Upper Itchen. Although particle size and colour varied, the results reveal persistent, catchment-wide contamination. They also confirm that even chalk streams – renowned for their biodiversity – are being affected by particle pollution, adding a new concern to the existing pressures of habitat loss, chemical pollution, water abstraction, and drought.
The research, which focuses on identifying and quantifying pollutants in the Upper Itchen, is still ongoing. Additional samples will 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 – expected later this year – will deliver the first comprehensive picture of particle pollution in a UK chalk stream. Results will be shared with landowners, farmers, local groups, and regulators, extending understanding well beyond the Itchen.