Natural radioactivity in building materials at Kalpakkam

The need for determination of natural radioactivity content in building materials arises from the growing attention paid to its potential radiation effects and consequent concern of many producers of such materials These materials have been analyzed for natural radioactivity due to presence of primordial radionuclide 238U, 232Th and 40K using gamma spectrometry. The activity of different building material obtained in this study ranged from 1-72 Bq/kg for 226Ra, 4-148 Bq/kg for 232Th and 38-1288 for 40K respectively. The radium equivalent activity (Raeq) values of all the building materials are lower than the limit of 370 Bq/kg which will produce an exposure of 1.5 mSv/yr to the inhabitants. In all cases both External hazard index Hex and Internal hazard index Hin in all the building materials collected and analysed in this paper is below unity. Based on the criterion formula for gamma activity the results presented indicate that the commonly used building materials in Kalpakkam could be used in building construction without exceeding the proposed radioactivity criterion level. (author)