Estimation of natural radioactivity in local and imported polished granite used as building materials in Saudi Arabia

Measurements of natural radioactivity in local and imported samples of commercial granites used in Saudi Arabia were carried out by using gamma-ray spectroscopy with hyper-pure germanium detector. The activity concentrations measured of granite samples were determined for 226Ra(from 1.53 to 77.16 Bq kg−1), 232Th (from 0.51 to 89.82 Bq kg−1) and 40K (from 19.47 to 1632.37 Bq kg−1). The corresponding average activity concentrations for 226Ra,232Th and 40K were 28.82, 34.83 and 665.08 Bq kg−1, respectively. The radiological hazard parameters (radium equivalent, gamma index, external index, internal index, absorbed dose and annual effective dose) were calculated to assess the radiation hazards associated with granite samples. The obtained results are lower than the recommended limits. The results were compared with the published data of other countries. The measurements will help in the development of standards and guidelines for the use and management of these materials.