MEASUREMENTS OF NATURAL RADIOACTIVITY an‎d ASSOCIATED RADIOLOGICAL HAZARDS IN SAND an‎d GRAVEL QUARRIES IN ASSIUT, EGYPT

This study contains 70 samples and covered a total of 36 different sand and gravel quarries in Assiut, Egypt. Activity concentration of ^226Ra, ^232Th and 40K were measured using γ-ray spectrometry (NaI (Tl) 3” x 3”). The average values of specific activity for ^226Ra, ^232Th and 40K in sand samples are 4.74, 4.10 and 109.82 Bq kg^-1, respectively, and in gravel samples these values are 6.01, 1.82 and 31.6 Bq kg^-1, respectively. These values are smaller than the world average values that reported by UNSCEAR 2000. Some radiological indices such as Radium equivalent activity, Absorbed dose rate, Annual Effective Dose Equivalent and Annual Gonadal Dose Equivalent, were calculated, to estimate the radiological hazards arising from using these row building materials in Assiut governorate, and found that, all the investigated quarries are safe from radiological view for use in building construction.