Assessment of natural radioactivity and radiological hazards in building materials used in the Tiruvannamalai District, Tamilnadu, India, using a statistical approach

One-hundred-fifty-one samples of six types of building materials were collected from different locations of the Tiruvannamalai District, Tamilnadu, and were analyzed using a gamma ray spectroscopy system. From the results, the highest values observed in the specific activities of 226Ra, 232Th and 40K were 116.1 (soil) 106.67 (sand) and 527.533 (tiles) in Bq kg−1, while the lowest values observed in the specific activities of the same radionuclides were 35.73, 37.75 and 159.83 for cement in Bq kg−1, respectively. The potential radiological hazards were assessed by calculating the radium equivalent activity (Raeq), the indoor absorbed gamma dose rate (DR), the annual effective dose rate (HR), the activity utilization index (I), the alpha index (Iα), the gamma index (Iγ), and the external hazard (Hex) and internal hazard (Hin) indices. The estimated mean value of the absorbed dose rate of 148.35 nGy h−1 is slightly higher than the world average value of 84 nGy h−1, and the annual effective dose in the studied samples is 0.1824 mSv y−1, which is lower than the recommended limit. Multivariate statistical methods are applied to determine the existing relationship between radionuclides and radiological health hazard parameters and to identify the maximum contribution of radionuclide in radioactivity. The values of the hazard indices were below the recommended levels; therefore, it is concluded that the buildings constructed from such materials are safe for the inhabitants. The findings from this research will be useful to assess the radiation hazards of building materials in humans.