Radiation dose estimation from the radioactivity analysis of lime and cement used in Bangladesh

The radioactivity concentrations of Th-232, Ra-226, K-40 and Cs-137 were measured using high-resolution gamma-ray spectrometry in limestone, powdered lime, by-product lime and cement used in Bangladesh. The activity concentrations, Ra equivalent activities, representative level index values for all samples and the effective dose equivalents due to the intake of the above-mentioned radionuclides in limestone and powdered lime by the adult group were estimated. The mean activity concentrations of Th-232, Ra-226 and K-40 were 60.8, 602 and 928 Bq kg(-1), respectively 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-232, Ra-226 and K-40 were observed to be 54.3, 29.7 and 523 Bq kg(-1), respectively. The presence of Cs-137 was not detectable in any of the studied samples. The measured average activities of Th-232, Ra-226 and K-40 for all samples were relatively higher than the world typical values except for Ra-226 in cement and by-product lime. The calculated mean Ra equivalent values for limestone, powdered lime, by-product lime and cement were 219, 349, 224 and 148 Bq kg(-1), respectively. The corresponding representative level index values were found to be 1.63, 2.63, 1.68 and 1.09, respectively. The mean effective dose equivalent values 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 powdered 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.