Assessment of natural radioactivity of sand used in Turkey

The natural radioactivity due to the presence of Ra-226, Th-232 and K-40 in sand samples used as building materials in Turkey was measured by gamma spectrometry. The measured activity in the sand samples ranged from 17 to 97 Bq kg(-1), 10 to 133 Bq kg(-1) and 116 to 955 Bq kg(-1) for Ra-226, Th-232 and K-40, respectively. The concentrations of these natural radionuclides were compared with the reported data for other countries. The radium equivalent activity (Ra-eq), the external hazard index (H-ex), the internal hazard index (H-in), the indoor absorbed dose rate in air and the annual effective dose rate were evaluated to assess the radiation hazard for people living in dwellings made of the materials studied. The Raeq values of sand samples are lower than the limit of 370 Bq kg(-1), equivalent to a gamma dose of 1.5 mSv yr(-1). This study shows that the measured sand samples do not pose any significant source of radiation hazard and are safe for use in building materials. Moreover, the experimental mass attenuation coefficients (mu/rho) of seven different sand samples were determined in the energy range 80-1332 keV photons by using the gamma ray transmission method. Experimental values of mass attenuation coefficient were compared with theoretical values obtained using the program XCOM. The calculated values and the experimental results of this work and the other results in the literature are found to be in good agreement. Chemical and structural analyses (XRD) of the sand samples were also undertaken.