The discoloration of rivers by effluents from the dyeing industry is at its most acute in the Severn Trent region. The NRA says that the problem has worsened as the industry has switched to reactive dyes. These give improved colour-fastness, but are poorly biodegradable in sewage treatment works. Ten rivers in the region are affected by colour pollution, compared to two or three a few years ago.
Other rivers affected by textile dyes inclu