Author(s)

S. F. Hassan¹, M. A. M. Mahmoud^1*, M. A. E. Abd El-Rahman²

¹Nuclear Materials Authority, Cairo, Egypt.
²Military Technical College, Cairo, Egypt.

The studied area at Wadi Nugrus, Southeastern Desert, Egypt, is located between lat. 24°41'00'' and 24°41'35''N and long. 34°36'47'' and 34°37'09''E. The rock types are represented by layered metagabbros, biotite schists, gneisses, granodiorites, and Muscovite granites. The muscovite granite of Wadi Nugrus, is small exposure in size (~5.0 km²), emplaced along NW-SE trend, with about 0.5 - 4.5 Km in length and 100 - 250 m in width and intruding the biotite schists. The studied muscovite granite is composed mainly of plagioclases, potash feldspars, quartz, biotite and muscovite. The recorded minerals assemblage can be classified into secondary U-minerals (uranophane and meta-autunite), U-bearing minerals (uranothorite and columbite) and accessory minerals (zircon, flourite, allanite, zinnwaldite and hematite). The U/eU is more unity where, the measured chemical uranium is higher than the measured equivalent uranium in the most analyzed samples especially in trenches, which reflect disequilibrium state. The activity concentrations range from 251.72 to 1096.2 Bq·kg^-1 for ²³²Th, from 494 to 2593.5 Bq·kg^-1 for ²²⁶Ra, and from 1314.6 to 1846.7 Bq·kg^-1 for ⁴⁰K. The obtained radiological data show that the average internal and external hazard indices are 9.11 and 5.78, respectively which are more than unity and highly exceeding the permissible limits (International Commission on Radiation Protection, ICRP). The internal and external hazards are mainly due to ²²⁶Ra nuclei while the absorbed dose rate (nGy/h) is related to ²³²Th nuclei. The contributions of the three nuclei in the total absorbed dose rates and internal and external hazardous, for ²²⁶Ra, it contributes by 72% in H_in, 57% in H_ex and 55% of D_R, for ²³²Th it contributes by 24% in H_in, 37% in H_ex and 36.9% of D_R, while for ⁴⁰K it contributes by 4.1% in H_in, 6.4% in H_ex and 8.1% of D_R.

Muscovite, Peraluminous, Uranium, Radiation Exposure Levels, Radon Concentration

Hassan, S. , Mahmoud, M. and Abd El-Rahman, M. (2016) Effect of Radioactive Minerals Potentiality and Primordial Nuclei Distribution on Radiation Exposure Levels within Muscovite Granite, Wadi Nugrus, Southeastern Desert, Egypt. Journal of Geoscience and Environment Protection, 4, 62-78. doi: 10.4236/gep.2016.43006.