Variation in the uranium isotopic ratios super( 234)U/ super( 238)U, super( 238)U/total-U and super( 234)U/total-U in Indian soil samples: Application to environmental monitoring

This paper based on measurement of uranium concentration and 234U/238U activity ratios in soil samples collected from Nalgonda district, Andhra Pradesh, India, a proposed mining site, was carried out to find the spatial distribution of uranium and the state of secular equilibrium of super( 234)U/ super( 238)U to examine the possibility of applying uranium concentration and uranium isotopic activity ratios to detect any hydrogeochemical changes in the environment during/post-operation. Soil samples were collected and analyzed for uranium concentration using the conventional UV fluorimetric method, showing a uranium concentration in the range of 0.7 plus or minus 0.2 ppm to 7.9 plus or minus 0.4 ppm with an average of 3.4 ppm, and super( 234)U/ super( 238)U activity ratios were estimated using the alpha spectrometry technique, showing an activity ratio in the range of 0.92 plus or minus 0.11 to 1.02 plus or minus 0.11. The super( 234)U/ super( 238)U activity ratio obtained indicated that these two uranium isotopes are in the state of secular radioactive equilibrium.