Environmental impact assessement and determination of radiogenic heat production in the North Jabal Maghrabiyah area, Central Eastern Desert, Egypt

Abstract

The present study deals essentially with the establishment of the environmental natural radiation levels in the surveyed area. These will provide base-line information that can be used as a reference to detect and determine the amount and extent of any possible future variation or contamination in the natural radioactivity levels that might occur in the study area due to any potential incidents involving release of nuclear radiation or fallout of nuclear fission products that could affect both terrestrial and atmospheric radioactivity. A map of radiogenic heat production (RHP) was built from the airborne spectral gamma-ray data of North Jabal Maghrabiyah area, central Eastern Desert, Egypt. The area of study reflects radiogenic heat production varying from 0.03 to 6.44 μWm-3, averaging a value of 0.99 μWm-3, while their standard deviation reaches 0.61 μWm-3. The maximum values are associated with the acidic rocks in the northeastern, central, southeastern, northeastern and eastern parts of the area of study. Results showed several levels of radiation as follows: (less than 0.39 mSv/y), (from 0.39 to 0.59 mSv/y), (higher than 0.59 and reached to 2.01 mSv/y). The dose rate more than 1 mSv/y is considered the radioactivity hazard level which represented mainly with late to post tectonic Potassic calc-alkaline granitoids, calc-alkaline granitoids, Muꞌtiq group, Dukhan volcanic/subvolcanic group, Atallah felsite, Parts of Quaternary deposits, Hammamat sediments, parts of Tarif, Dakhlah and Duwwi Formations. Thus, the North Jabal Maghrabiyah area can be considered as high RHP, because of the relatively high radioactive concentrations. There are good relationships between the derived RHP and the three radioactive elements, equivalent Uranium (eU), equivalent Thorium (eTh) and Potassium (K), as represented by the binary relationship between any of two elements. The importance of radiogenic heat production is the source of ground thermal energy.