DETERMINATION AND EVALUATION OF NATURAL RADIOACTIVE NUCLIDES IN DRINKING-WATER FROM SELECTED WATER-SUPPLIES OF THE ERZGEBIRGE AND THE VOGTLAND REGIONS

Investigations have been carried out to determine the natural radionuc lide content of drinking and raw waters, in water supplies of the Erzg ebirge and the Vogtland region. The maximum concentration values for t he typical nuclides have proved to be lower than the concentration lev els published in 1995 by the German Commission on Radiological Protect ion (SSK) for waters which are possibly susceptible to influences from uranium mining. Taking into consideration the nuclides Pb-210, Po-210 , Ra-226, U-234, U-238, and Th-232, the average annual ingestion dose totals 20 mu Sv for infants, and 15 mu SV for adults, which is relativ ely low compared to the other pathways of natural radiation exposure. Under application of conservative assumptions, the annual ingestion do se can reach 480 mu Sv and 360 mu Sv, respectively. The dose-predomina te nuclides are usually Ra-226 and Pb-210. The reduction of concentrat ions of natural radionuclides in drinking water, which is achieved thr ough the treatment of raw waters in water works is usually low. It dec reases in the following order: Pb-210, Ra-226, Po-210, thorium isotope s, uranium isotopes.