‘Citizen scientists make a vital difference’: the locals who proved the River Wye was polluted

Angler Gordon Green, a researcher for the Wye Salmon Association, takes water samples from the river at the Huntsham Bridge near Symonds Yat. Photograph: Adrian Sherratt/the Observer

A few times a week, a group of volunteers dotted along the Yazor Brook, which rises in a rural catchment and flows into the River Wye at Hereford, brave the brambles and muddy banks to take samples of the gently flowing water.

They conduct the tests on at least four sites along the brook and upload their results online. They are now among more than 200 citizen scientists who regularly test the River Wye from its source in the Cambrian mountains to the Severn estuary, compared with the sporadic testing by regulators.