RADIATION-DOSE ESTIMATION FROM THE RADIOACTIVITY ANALYSIS OF LIME ANDCEMENT USED IN BANGLADESH

The radioactivity concentrations of Th-232, Ra-226, K-40 and Cs-137 we re measured using high-resolution gamma-ray spectrometry in limestone, powdered lime, by-product lime and cement used in Bangladesh. The act ivity concentrations, Ra equivalent activities, representative level i ndex values for all samples and the effective dose equivalents due to the intake of the above-mentioned radionuclides in limestone and powde red lime by the adult group were estimated. The mean activity concentr ations of Th-232, Ra-226 and K-40 were 60.8, 602 and 928 Bq kg(-1), re spectively for limestone, 107, 68.0 and 1660 Bq kg(-1), respectively, for powdered lime and 83.0, 31.0 and 972 Bq kg(-1), respectively, for by-product lime. For cement, the mean activity concentrations of Th-23 2, Ra-226 and K-40 were observed to be 54.3, 29.7 and 523 Bq kg(-1), r espectively. The presence of Cs-137 was not detectable in any of the s tudied samples. The measured average activities of Th-232, Ra-226 and K-40 for all samples were relatively higher than the world typical val ues except for Ra-226 in cement and by-product lime. The calculated me an Ra equivalent values for limestone, powdered lime, by-product lime and cement were 219, 349, 224 and 148 Bq kg(-1), respectively. The cor responding representative level index values were found to be 1.63, 2. 63, 1.68 and 1.09, respectively. The mean effective dose equivalent va lues of Th-232, Ra-226 and K-40 for limestone were 56.5 x 10(-7), 41.6 x 10(-8) and 50.8 x 10(-10) Sv g(-1), respectively, and those for pow dered lime were 99.5 x 10(-7), 46.9 x 10(-8) and 91.3 x 10(-10) Sv g(- 1) respectively. 1998 Elsevier Science Ltd. (C) All rights reserved.