Dose effect for South Serbians due to 238U in natural drinking water

The use of depleted uranium ammunition in South Serbia during the 1999 Kosovo conflict raised a great deal of public concern in the Balkans. Radioactivity levels of U-238 in 20 wells and lake water samples were checked from the viewpoint of internal radiation exposure for South Serbian subjects. We have measured U-238 concentration using inductively coupled plasma mass spectrometry, whereas thermal ionisation mass spectrometry has been used for the measurement of isotope ratios, e.g. U-234/U-238 and U-235/U-238. The concentration of uranium in water samples varies in the range 1.37-63.18 mBq/L. U-234 belongs to the U-238 natural radioactive decay series, and at secular equilibrium, the abundance ratio, U-234/U-238, corresponds to the ratio of their half-lives. The U-234/U-238 activity ratio varies in the range 0.88-2.2 and U-235/U-238 isotope ratio varies from 0.00698 to 0.00745. These findings indicate that uranium in water was a mixture of natural and anthropogenic origin. The annual effective dose due to U-238 was estimated to be in the range 9.2 X 10(-5)-2.1 X 10(-3) mSv.