Natural radioactivity measurement in sedimentary rock samples collected from the bahariya oasis, Western Desert, Egypt

Abstract EN

The specific activities of natural radionuclides in ten sedimentary rocks samples collected from the Bahariya oasis area of Western Desert district, Egypt, have been evaluated.

Experimental results were obtained by using a high-purity germanium (HPGe) detector and gamma-ray spectrometry analysis system.

It was found that, the sedimentary rocks specific activity ranges from 6.9 to 43.5 Bq kg-1 for 238U, between 0.5 and 33.9 Bq kg-1 for 232Th and between 6.5 and 1007.7 Bq kg-1 for 40K.

The activity of the Bahariya Formation rises from base to top and reaches 1007.7 Bq kg-1 for 40K which records the highest in the whole area at all in its upper most glauconitic siltstone, mudstone layer.

In addition, it was found that the activity increases with the occurrence of Fe-oxide minerals as in the ferruginous sandstones, glauconite in siltstone and mudstone layers in the Bahariya and Naqb formations.

The activity of the carbonate rocks shows the highest in the Naqb Formation (pinky limestone), less in the Qazzun Formation and the lowest in the Khoman Chalk, particularly for Th and K activity.

The average value of gamma dose rate (30.04 nGy/h) and the average annual effective dose (0.184 mSv y-1) obtained in this study are lower than the worldwide dose rate average value (55 nGy/h) and the maximum annual dose to members of the public (1.0 mSv y-1), respectively.