Measurement of natural radioactivity in Jordanian building materials and their contribution to the public indoor gamma dose rate

This study is undertaken to determine the activity concentration of 226Ra, 232Th and 40K in samples of commonly used building materials in Jordan. Samples of seven different materials were collected from construction sites and local agencies supplying raw construction materials and analyzed using a HPGe gamma-ray spectrometer, taking into account self-attenuation in bulk samples. The average specific activity concentrations of 226Ra, 232Th, and 40K ranged from 2.84 to 41.52, 0.78 to 58.42. and 3.74 to 897 Bq/kg, respectively. All the samples had radium equivalent activities well below the limit of 370 Bq/kg set by the Organization for Economic Cooperation and Development (OECD, 1979). External and internal hazard indices, absorbed dose and annual effective dose rate associated with the radionuclides of interest were calculated and compared with the international legislation and guidance. In general, most of the activities did not exceed the recommended international limits, except for granite and ceramic samples which are usually used as secondary building materials in Jordan. - highlights: • The doses and risk factors associated with exposure to natural gamma radiation. • External and internal hazard indices, absorbed dose and annual effective dose rate associated with the radionuclides of interest were calculated. • Only granite and ceramic samples, usually used as secondary building materials, were found to exceed recommended limits