The Cooling Water of Power Stations: A New Factor in the Environment of Marine and Freshwater Invertebrates

Modern industry brings many new factors into the natural environment, which may be expected to affect the natural balance. Although the literature regarding many such factors is abundant, it seems that the problems connected with the effect of power station discharges and how aquatic organisms respond to them are still largely a matter for speculation (see, however, Van Vliet 1957). A wide field is open for biological investigations on the response of aquatic organisms to these new factors. The increasing demand of modern industry for electric power brings every year more power stations on the rivers and by the sea. Cooling water, either from the sea or from the river, is essential for running them. In 1957 about 76 000 million units of electricity were supplied in England and Wales by the Central Electricity Authority. Nearly all, of this, together with current generated for its own use, was generated in thermal plant (steam turbine and diesel engines) and required an estimated 4 x 10's gallons (18 2 x 1012 litres) of cooling water. Very approximately, a third of this was river water, a third sea water or brackish estuarine water, and a third water that had been recirculated over cooling towers; of the latter, about 300 on average would be fresh make-up water and about 20% returned to the water course, the 1 % difference being evaporated. All this water contains living organisms, if only bacteria and fungi. Lt is intended in this paper to give a general picture of the conditions created by power stations in freshwater and marine environments and some information on the animal species involved and their response to the conditions they experience.