Treated and untreated sewage greatest threat to river biodiversity, says study

Discoloured liquid being discharged into the River Thames. Photograph: Carl Court/Getty Images

Pollution from treated and untreated sewage is the greatest threat to river biodiversity, causing more damage than runoff from farms, according to research.

There is a need for more regulation of water companies and improvements at their treatment plans to protect rivers, say the authors of the study.