Hundreds of harmful chemicals found in all English rivers

Hundreds of harmful chemicals, some of them banned, have been found in various mixtures across all 171 river and groundwater catchments tested in England in 2024, according to data from the Environment Agency (EA), analysed by the Guardian and Watershed Investigations.

- Leana Hosea , Rachel Salvidge

About 250 are classified as very toxic, toxic or harmful to aquatic life, according to the European Chemicals Agency (ECHA), and a banned carcinogenic "forever chemical" was among 20 "substances of very high concern" found.

"What this shows is that the way we monitor and manage chemicals in our rivers is completely unfit for purpose," said Alistair Boxall, a professor in environmental science at the University of York. "Although it depends on the concentrations, a lot of these are very toxic. We know they target algae, invertebrates and fish. If you've got a mixture of a few hundred substances, they are potentially working together and exacerbating the effect."

Nick Measham, chief executive of WildFish conservation charity, said: "Our invertebrate monitoring shows clear evidence of significant chemical impact across all the 100-plus rivers we monitor ... It makes poo in rivers look like a second-order problem."