Measurement of natural radioactivity in building materials in Qena city, Upper Egypt

Building materials cause direct radiation exposure because of their radium, thorium and potassium content. In this paper, samples of commonly used building materials (bricks, cement, gypsum, ceramics, marble, limestone and granite) in Qena city, Upper Egypt have been collected randomly over the city. The samples were tested for their radioactivity contents by using gamma spectroscopic measurements. The results show that the highest mean value of 226Ra activity is 205 ± 83 Bq kg−1 measured in marble. The corresponding value of 232Th is 118 ± 14 Bq kg−1 measured in granite. For 40K this value is (8.7 ± 3.9) × 102 Bq kg−1 measured in marble. The average concentrations of the three radionuclides in the different building materials are 116 ± 54, 64 ± 34 and (4.8 ± 2.2) × 102 Bq kg−1 for 226Ra, 232Th and 40K, respectively. Radium equivalent activities and various hazard indices were also calculated to assess the radiation hazard. The maximum mean of radium equivalent activity Raeq is 436 ± 199 Bq kg−1 calculated in marble. The highest radioactivity level and dose rate in air from these materials were calculated in marble.