Assessment of radiation hazards due to exposure to radionuclides in marble and ceramic commonly used as decorative building materials in Egypt

The concentrations of 238 U ( 226 Ra), 232 Th, and 40 K for the commonly used decorative building materials (15 marble and 15 ceramic) in Egypt were measured using gamma spectroscopy system. Radionuclides concentrations in marble samples were ranged from: ND to 49.92 ± 7.74 Bq kg −1 for 226 Ra, 8.30 ± 1.70 to 119.52 ± 16.00 Bq kg −1 for 232 Th, and 32.60 ± 4.25 to 2238.33 ± 242.66 Bq kg −1 for 40 K while in ceramic samples the concentration ranged from: 28.42 ± 5.41 to 118.70 ± 20.34 Bq kg −1 for 226 Ra, 30.65 ± 5.49 to 114.15 ± 18.78 Bq kg −1 for 232 Th, and 389.54 ± 49.57 to 1069.83 ± 124.50 Bq kg −1 for 40 K, respectively. These results imply that radium and thorium concentrations were below the worldwide recommended values but potassium was above the standard guideline. Radiological hazards indices of radium equivalent activity (Ra eq ), external and internal hazard indices: H ex and H in , respectively, and annual effective doses of the investigated materials due to the presence of those radionuclides were calculated and had values less than the worldwide recommended values of 370 Bq kg −1 , unity and 1 mSv y −1 , respectively. Therefore, the studied types of marble and ceramic can be safely used as decorative building materials.