Natural activities of 238U, 232Th and 40K in some Indian building materials

The activity concentrations of Ra-226, Th-232 and K-40 have been determined by gamma-ray spectrometry. The measured activity in the selected building materials ranges from (3.2 to 151.7 Bq/kg), 14 to 63.7 Bq/kg and 24.3 to 121.5 Bq/kg for Ra-226, Th-232 and K-40 respectively. The activity concentration of U-238 has been determined using fission track technique and the value ranges from 0.11 to 3.85 ppm. The concentrations for these natural radionuclides are compared with the reported data from other countries. Radium-equivalent activities (Ra-cq) are calculated for the measured samples to assess the radiation hazards arising due to the use of these materials in the construction of dwellings. All building materials have shown Racq activities lower than the limit set in the Organization for Economic Cooperation and Development (OECD) report (370 Bq/kg), equivalent to external gamma dose of 1.5 mSv yr(-1). A good correlation has been observed between U-238 and Ra-226 in these materials. (C) 2003 Elsevier Ltd. All rights reserved.