URANIUM AND (PO)-P-210 RADIONUCLIDES IN DRINKING WATER IN SOUTHERN BULGARIA AND EXPECTED RADIATION DOSES

The activity concentrations of the naturally occurring radionuclides U-238, U-234 and Po-210 have been determined for the first time in drinking water from certain sources in Southern Bulgaria using nuclear and radiochemical methods. The results obtained for the water samples vary in the intervals 0.6-678 mBq l(-1) for U-238, 1.4-1484 mBq l(-1) for U-234, <0.3-13.6 mBq l(-1) for Po-210 and 1.04-10.6 for the U-234/U-238 ratio. The annual effective dose from U-238, U-234 and Po-210 ranges from 1.09 to 44.1 mu Sv y(-1), 0.78 to 46.8 mu Sv y(-1) and 0.77 to 62.8 mu Sv y(-1) for infants, children and adults, respectively. The annual effective dose due to consumption of drinking water is below the individual dose criterion of 100 mu Sv y(-1) recommended by the World Health Organization. The natural radioactivity of the water sources investigated is below the national and international limits.