AERORADIOSPECTROMETRY IN THE LITHOLOGICAL MAPPING AND ENVIRONMENTAL MONITORING OF WADI ARABA AREA
Mohamed A. El-Sadek* and Ahmed A. Ammar
Nuclear Materials Authority
P.O. Box 530 Maadi, Cairo, Egypt
Ahmed M. Sabry
Faculty of Science, Ain Shams University
The aim of this airborne radiospectrometric study is to delineate, modify, and correct the regional lithology as well as to define and monitor the environmental background of Wadi Araba area, Northern Eastern Desert, Egypt. The study uses the aerial radiospectrometric survey data and the regional geological map as the main sources of information.
The aeroradiospectrometric survey data have been statistically analyzed and correlated with the compiled geological map of the area under study. This analysis resulted in the delineation of several new interpreted radiometric lithologic (IRL) units.
Corresponding statistical characteristics have been computed and established for each IRL unit in the investigated area. The various four statistical inference tests were applied to the total-count (T.C.) radiometric characteristic statistics to determine whether or not a statistically significant difference exists between the computed statistics possessed by the different IRL units (normal distributions) in the studied area.
The four tests include the Bartlett’s, Analysis of Variance (ANOVA), Fisher’s (F), and Student’s (t). From the results of the statistical inference tests, only one group of IRL units from Rod El-Hamal Formation (RHF-2, RHF-3, and RHF-4) as well as only one group from Wadi Irkas Formation (WIF-2, WIF-5, and WIF-7) could be considered as belonging to one and same parent lithological population. Moreover, one pair from Wadi Irkas Formation (WIF-3 and WIF-8), as well as one group (QtS-4, QtS-7, and QtS-8) and three pairs (QtS-3 and QtS-5), (QtS-10 and QtS-17) and (QtS-12 and QtS-13) from Quaternary Sediments could be considered as belonging to one and the same parent lithological population from the radioactivity point of view.
The dose-rate map of the study area shows that the maximum dose-rate value originating from the terrestrial gamma-radiation reaches 0.36 mSv/y. This value is associated with the Rod El-Hamal formation, which remains in the safe side and within the maximum permissible safe radiation dose (1.0 mSv/y) without harm to the individual, with continuous external irradiation of the whole body.