Radiological and environmental studies on the metamorphosed sandstones at Wadi Sikait area, southeastern desert, Egypt

Abstract

Abstract Wadi Sikait area lies in the southern part of the Eastern Desert of Egypt along the upper stream of Wadi.Sikait. The exposed rock units in Wadi Sikait area are ophiolitic mélange roccks, metamorphosed sandstones, and porphyritic granites, lamprophyre dykes, in addition to fluorite and quartz veins. The activity concentrations of various radionuclides are measured by NaI-Tl activated detector and the radioactive mineralization were determined by Alpha track technique using CR-39 films. Radiometric investigations indicate that 238U activity concentrations range between 37.2 and 520.4 with average 148.8 BqKg−1, 232Th activity concentrations vary between 8.08 and 366.99 BqKg−1 with 76.75 BqKg−1 as an average. The studied metamorphosed sandstones have higher values relative the world concentration levels. High uranium content of the metamorphosed sandstone is attributed to presence radioactive minerals like uranophane and autonite, in addition to accessory minerals like allanite, zircon and monazite. Other U-bearing minerals are also recorded as biotite, muscovite, iron oxides and clays. Absorbed Dose Rate (D), annual effective dose equivalent (AEDE), radium equivalent activity (Raeq), external (Hex) and internal (Hin) hazard index, in addition to activity gamma index (Iγ) caused by gamma emitting natural radionuclide are determined from the obtained values of 226Ra, 232Th and 40K. Fairly, many of the studied metamorphosed sandstone do not satisfy the universal standards.