Estimation of Natural Radionuclides and Rare Earth Elements Concentration of the Rocks of Abu Khuruq Ring Complex, Egypt

The naturally occurring radionuclides (radium-226, thorium-232, potassium-40 and radon-222) were investigated in the alkaline rocks of Abu Khuruq Ring, southern Eastern Desert, Egypt. A high-resolution germanium detector was used for the detection of K-40, Th-232, and Ra-226 (Canberra, GR4020 model) while Rn-222 concentration was measured by the Alpha-Guard Saphymo GmbH system, model PQ 2000 (AG). Major and rare earth elements (REEs) were assessed using the inductively coupled plasma mass spectrometry and atomic emission spectrometry techniques. Positive correlations were observed between REEs, indicating symmetrical chemical properties and their overall presence in the parent material-also, a positive correlation was observed between effective radium content and radon concentrations pointing to the strong linear dependency between both contents in the studied rocks. The average values of activity concentration of K-40, Th-232, Ra-226, and Rn-222 were less than the suggested level by a factor of 1.38%, 3.16%, 2.09%, and 1.16%, respectively. Significant variations were found among the radiological hazards parameters, e.g., the mean value of the annual effective dose (0.55 mSv y(-1)) was more than the global reference value (0.41 mSv y(-1)) by a factor of 1.34. The calculated average value of the gamma index was 0.90, and that of the alpha index was 0.37. H-ex, H-in and Ra-eq showed fewer average values than the standard values of unity and 370 Bq kg(-1), respectively.