干旱区生态环境知识资源中心

Remote sensing and radiometric survey techniques in the area between Qusier and Mersa Alam show variation of content of natural radioactivity in Wadi Wizr area, Eastern Desert of Egypt Gamma-ray, and laser fluorimetry were applied to measure the natural radioactivity content in representative content in representative samples from Wadi Wizr. The concentration of Ra-226 ranged from 36 to 661 Bq kg(-1), while the radioactivity ratio between Ra-226/Pb-214 and Pb-214/Bi-214 ranged from 0.7 to 1.4. The activity ratio U-238/Ra-226% was found to be in the range 6.4%-72.2%. A state of disequilibrium between the two radionuclides in the uranium series is clear. The trend of disequilibrium was obvious in all the investigated sites and correlating both radionuclides, U-238/Ra-226 demonstrated the site variation influence. Samples were also analyzed by XRD to reveal their mineral composition. (C) 2003 Published by Elsevier Science Ltd.