Evaluation of outdoor radon levels and its dependence on the radium content in soil in the environs of Belagavi India

The paper presents the seasonal variation of outdoor radon levels and the measured lung dose to the population of the Belagavi region of India. The outdoor radon levels were measured in different seasons using LR-115 (type II) films fixed in a pin-hole cup detector. The outdoor radon levels in this work were found to be high in summer with values ranging from 11.8 to 27.3 Bq m-3 with a mean value of 20.0 Bq m-3. Lower radon levels were observed in monsoon season and the values range from 3.8 to 15.8 Bq m-3, with a mean value of 10.0 Bq m-3. The potential alpha energy concentration was maximum in summer with a mean value of 3.3 mWLM. The mean annual exposure was found to be 1.4 mWLM and the mean annual inhalation dose was 0.2 mSv y-1. The activity of 226Ra in soils was measured using a NaI (Tl) detector based on gamma ray spectrometer. The 226Ra activity of the study area was in the range of 16.5 to 70.4 Bq kg-1 with a mean value of 32.4 Bq kg-1. The correlation coefficient between the radium content in soil and outdoor radon levels was studied. The present study shows a significant correlation of 0.7, between outdoor radon levels and the radium content in the soil.