ABSTRACT
In the 1950s, the waters of the River Derwent, in north-central England, flowed unpolluted until they reached the Borough of Derby’s two sewer outfalls—one that occasionally released raw sewage and another that routinely discharged inadequately treated effluent from the local sewage treatment works. The river then passed through land owned by British Celanese Ld., whose effluent also polluted and warmed it. Downstream, discharge 207from the British Electricity Authority’s power station further increased the river’s temperature.
