NATURAL RADIOACTIVITY IN ZAMBIAN BUILDING-MATERIALS COLLECTED FROM LUSAKA

Samples of natural and manufactures building materials collected around Lusaka have been analyzed for natural radionuclides using gamma-spectrometry. A simple comparison of the specific radioactivities of primordial radionuclides in these materials to the world averages for soil (25 Bq kg(-1) U-238, 25 Bg kg(-1) Th-232, 370 Bq kg(-1) K-40 and 89 Bq kg(-1) Ra-eq) shows that, of the nine types of samples analyzed, only burnt clay bricks (for U-238, Th-232 and K-40), cement roofing tiles (for U-238), building and river sands (for Th-232 and K-40) have greater activities than does soil. Radiological evaluation of specific radioactivities in these materials indicates that all materials meet the external gamma-ray dose limitation of 1.5 mSv y(-1), that is, all samples have a radium equivalent activity of less than 370 Bq kg(-1).