Assessment of natural radioactivity in major building materials of Xiangyang, China

The activity concentrations of K-40, Ra-226 and Th-232 in the commonly used building materials collected from Xiangyang were measured using NaI (Tl) gamma spectrometer. The radioactivity values of K-40, Ra-226 and Th-232 in the studied samples ranged from 130.5 to 1006.3, 8.4 to 164.0, and 8.7 to 145.6 Bq kg(-1), respectively. The concentrations of these radionuclides have been compared with the typical published world values. Radium equivalent activity, external and internal hazard indexes, external and internal exposure indexes, indoor air absorbed dose rate and annual effective dose rate have been calculated to assess the potential radiological hazard associated with natural radionuclides in the studied materials. The calculated values of all the assessed indices in the analyzed building materials except for fly ash are below the internationally accepted limits indicating that these building materials can be safely used in dwellings construction and do not lead to any significant radiation exposure to occupants. Nevertheless, the annual effective dose rate values of all fly ash samples, external and internal hazard indexes values in most fly ash samples exceed the recommended values. It is, therefore, desirable to regularly monitor the natural radioactivity level of the building materials products made from fly ash.