A huge citizen testing blitz of rivers across Britain this summer has found 75% are in poor ecological health as a result of pollution from water companies and agricultural runoff.

Over the weekend of 7-10 June, more than 2,600 volunteers for Earthwatch Europe measured the water quality of their local rivers, providing a snapshot of the health of the country’s rivers. 

During the Great UK WaterBlitz, the citizen scientists measured the levels of two polluting nutrients: nitrates and phosphates, which are commonly present in treated and untreated sewage, as well as in fertilizers that wash off farmland.