Natural radioactivity and radiological hazards of building materials in Xianyang, China

Common building materials collected from Xianyang, China were analyzed for the natural radioactivity of 226Ra, 232Th and 40K using γ-ray spectroscopy. The average activity concentration of 226Ra, 232Th and 40K in the studied building materials ranges from 13.4 to 69.9, 13.1–99.1 and 124.7–915.1 Bq kg−1, respectively. The measured activity concentrations for these radionuclides were compared with the reported data of other countries and with the worldwide average activity of soil. To assess the radiation hazard of the natural radioactivity in all samples to the people, the radium equivalent activity, external hazard index, internal hazard index, indoor absorbed dose rate and total annual effective dose were estimated. The radium equivalent activities of the studied samples are below the internationally accepted values. The external hazard index and internal hazard index of all analyzed building materials are less than unity. The mean values of indoor absorbed dose rate for all building materials except for lime are higher than the world population-weighted average of 84 nGy h−1 and the total annual effective dose values of building materials are lower than 1 mSv y−1 except for some cyan brick samples. The study shows the measured building materials do not pose significant source of radiation hazard and are safe for use in the construction of dwellings. - Highlights: ► Natural radioactivity in building materials was determined by gamma ray spectrometry. ► The radiological hazard of studied building materials is within the recommended safety limit. ► Most of the studied building materials do not pose significant radiation risk to residents.