Natural radioactivity in springs of Sverdlovsk region, Middle Urals, Russia

Activity concentrations of natural radionuclides were determined in water from 31 springs of Sverdlovsk region, Middle Urals, Russia. Activity concentrations of 222Rn varied from 2.4 to 161 Bq L−1 providing the average annual internal dose exposure of 0.27 mSv. The maximal 238U and 232Th activities were 0.124 Bq L−1 and 0.005 Bq L−1 respectively resulting in insignificant risk. No correlation between activities of 222Rn and 232Th or 238U were found. Activity concentrations of 226Ra determined in seven springs with the highest radon content varied from 0.1 to 0.87 mBq L−1 providing annual doses of 0.02–0.18 µSv y−1.