Measurement of natural radioactivity in granites and its quartz-bearing gold at El-Fawakhir area (Central Eastern Desert), Egypt

The distribution of natural radionuclides (Ra-226, Th-232 and K-40) in Granites and its quartz-bearing gold at El-Fawakhir area (Central Eastern Desert, Egypt) were measured by using gamma-ray spectroscopy [NaI (Tl) 3 '' x 3 '']. X-Ray Fluorescence technique was used for chemical analyses of the studied samples. The specific activity of Ra-226, Th-232 and K-40 values are in range (3 +/- 0.5 to 43 +/- 2 Bqkg(-1)), ( 5 +/- 0.7 to 41 +/- 2 Bqkg(-1)) and (128 +/- 6 to 682 +/- 35 Bqkg(-1)) respectively. The absorbed dose rates ranged from 13.8 to 58.4 nGy h(-1), where the total effective dose rates were determined to be between 16.7 and 70.9 mu Svy(-1). The maximum external hazard index (H-ex) is 0.3 nGyh(-1). The calculated values of the excess lifetime cancer risks (ELCR) and annual effective dose rate values are in between (8.48 x 10(-5) and 2.63 x 10(-4)) and (24.2 and 72.9 mu Svy(-1)) respectively. Geochemically, the studied granites consist of major oxides, they are characterized by SiO2, K2O, Na2O, Al2O3, and depleted in CaO, MgO, TiO2, and P2O5. The average absorbed dose rate (D-o) in air is 37.8 nGyh(-1) for the whole studied samples, this value is about 3.78% of the 1.0 mSvy(-1) recommended by (ICRP-60,1991) to the public, so there is no radiological risk for the workers in that area. Copyright (C) 2015, The Egyptian Society of Radiation Sciences and Applications. Production and hosting by Elsevier B.V.