Natural radioactivity in soil and radiation levels of Rajasthan

The results of the measurement of natural radioactivity in soil collected from various locations of three districts of Rajasthan state using the gamma spectrometry technique are presented. The data on calculated and measured values of outdoor air absorbed dose rates due to terrestrial gamma radiation at each location are also discussed. It has been observed that the concentrations of the natural radionuclides viz., K-40 Ra-226 and Th-232 in the soils vary from 50 to 137 Bq.kg(-1), from 30 to 78 Bq.kg(-1) and from 43 to 106 Bq.kg(-1) respectively. It has also been observed that on the average, the outdoor terrestrial gamma air absorbed dose rate is about 6.7 x 10(-8) Gy.h(-1) for the three districts and the corresponding outdoor annual effective dose of 8.2 x 10(-5) Sv. Weak correlations have been observed between the concentration of K-40 and that of Ra-226 and Th-232.