Indoor radiation levels in the proposed uranium mining areas of Andhra Pradesh, India

Lambapur and Peddagattu areas in the Nalgonda district of Andhra Pradesh, India are found to have significant uranium mineralization. Studies made by Atomic Minerals Directorate of Exploration and Research (AMDER), Hyderabad revealed that this mineralization could be a commercially viable source for extraction of uranium mineral. This paper reviews our studies taken up to establish base-line data of indoor radiation levels in the proposed uranium mining areas before the actual mining is taken up. The mean indoor radon and thoron levels in these areas are found to be 75.4 and 70.6 Bq.m-3, respectively. Whereas the average effective dose due to indoor radon, thoron and their progenies is found to be 4.9 mSv.y-l. A comparative study in these areas has shown that the radon and thoron levels are relatively higher in the mud type of dwellings. Since the mud is taken from the local soil, it can be concluded that the local soil contributes significantly to the indoor radiation levels. The average of the measured natural background gamma radiation levels in this area is found to be (2.51 ± 0.42) x 103 μGy.y-l. (author)