Natural radioactivity levels in building materials used in Egypt

All building materials contain various amounts of radioactive nuclides. The levels of natural radioactivity in 43 selected typical building materials used in the construction of walls, windows and doors were determined. For the first time, the radioactivity of iron was measured, revealing the existence of Co-60. A shielded high-purity germanium detector was used to measure the abundance of Ra-226, Th-232 and K-40. The materials examined in this work showed radioactivity levels below the limit estimated from radium equivalent activity for acceptable radiation doses attributable to building materials, except for the fact that one gypsum sample showed higher levels of activity than average world levels. The studied building materials were classified according to the radium equivalent activities, which varied from highest to lowest levels as follows: clay, cement, brick, gypsum except from Abu-Zaabal, sand, wood, iron, glass and hydrated lime The existence of the Cs-137 isotope in some building materials was confirmed and its concentration levels were determined (ranging from 0.04 to 21.156 Bq kg(-1)). The alpha-activity of radon was measured in a number of building materials using CR-39 detectors.