several toxic chemicals in British rivers are going undetected as pollution inspectors are using ineffective monitoring techniques. A study initiated by the uk government has identified two major problems with the testing methods of the British environment agency. First, the environment agency tests river water for only a few pollutants such as fertilisers and metals. Second, inspectors rarely sample river sediments, even though many pollutants are seldom found in the water itself and are attached to silt particles.

Researchers have found concentrations of toxic chemicals in sediments thousands of times here than those in river water. Colin Neal of the Institute of Hydrology in Wallingford, a coordinator of the study, says: "Several rivers in industrial Yorkshire are the most amazing chemical soups.'