Natural Radioactivity Assessment and Radiation Hazards of Pegmatite as a Building Material, Hafafit Area, Southeastern Desert, Egypt.

Sixty-seven sites of Hafafit pegmatite from the Southeastern Desert of Egypt were investigated radiometrically in the field using an in situ γ-ray spectrometer to determine eU, eTh, and K contents. The obtained results ranged from 0.4 to 6 ppm for eU with a mean value of 2.5 ppm, from 0.2 to 32 ppm for eTh with a mean value of 6.7 ppm, and from 0.7% to 5.4% for K with a mean value of 3.3%. Consequently, the radiological effects from these rocks were estimates by determination of the environmental parameters: gamma activity concentration index Iγ, external hazard index Hex, internal hazard index Hin, external absorbed dose rates in outdoor, and external absorbed dose rates in indoor air. The results obtained in this study showed that values U, Th, and K lie in the range of the acceptable world values. In addition, the calculated radiation hazard parameters (Iγ, Hex, and Hin) have values lower than the world values, while the calculated external absorbed dose rates (Dair) have values higher than the world and Egyptian permissible levels.