A COMPARATIVE STUDY OF RADIUM CONTENT AND RADON EXHALATION RATE FROM SOIL SAMPLES USING ACTIVE AND PASSIVE TECHNIQUES

Soil is the most important factor affecting the radon level in the human living environments. It depends not only on uranium and thorium contents but also on the physical and chemical properties of the soil. In this paper, the measurements of radium content and mass exhalation rate of radon from the soil samples collected from Uttarkashi area of Garhwal Himalaya are presented. The correlation between radium content and radon mass exhalation rate from soil has also been obtained. The radium was measured by gamma ray spectrometry, while the mass exhalation rate of radon has been determined by both active and passive methods. The radium activity in the soil of study area was found to vary from 45 +/- 7 to 285 +/- 29 Bq kg(-1) with an average of 99 Bq kg(-1). The radon mass exhalation rate was found to vary from 0.59 x 10(-5) to 2.2 x 10(-5) Bq kg(-1) h(-1) with an average of 1.4 x 10(-5) Bq kg(-1) h(-1) by passive technique and from 0.8 x 10(-5) to 3.2 x 10(-5) Bq kg(-1) h(-1) with an average of 1.5 x 10(-5) Bq kg(-1) h(-1) by active technique. The results suggest that the measured radium value is positively correlated with the radon mass exhalation rate measured with both the active and passive techniques.