Comparative assessment of natural radionuclide content of cement brands used within Nigeria and some countries in the world
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Date
2014
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Abstract
The gamma spectrometric analysis of different brands of cement used as building and construction material in
Nigeria has been carried out in this study. Samples of 12 brands of gray Ordinary Portland Cement (OPC) and 5
brands of white cement of six samples each were collected and analyzed for their radiological content using
gamma spectrometry method. The average value of 226Ra, 232Th, and 40K for OPC is 30.2 ± 10.4 Bq kg−1,
24.6 ± 7.1 Bq kg−1, and 251.3 ± 27.6 Bq kg−1 respectively and the average value for the white cement is
41.9 ± 16.7 Bq kg−1, 30.1 ± 9.4 Bq kg−1 and 340.2 ± 37.7 Bq kg−1 respectively. The total average content
of 226Ra, 232Th, and 40K for all the cement brand samples are 36.1 ± 13.6 Bq kg−1, 27.4 ± 8.3 Bq kg−1, and
295.8 ± 32.7 Bq kg−1 respectively. These values obtained are lower when compared to the world average
values(226Ra-50 Bq kg−1,232Th-50 Bq kg−1and40K-500 Bq kg−1)forbuildingmaterials.Theestimatedradium
equivalent activities (Raeq), representative index (Iγ), average absorbed γ-dose rate (D), the annual effective
dose rate (AEDE), annual gonadal dose equivalent (AGDE) external and internal hazard indices and the Excess
life cancerrisk (ELCR)werelowerthantherecommendedsafelimitandarecomparablewithresultsfromsimilar
studies conducted in othercountries. The evaluated mean gonadal dose equivalents of three cement brandsam
ples were found to be higher than the world average for building material while others are less than the world
average. A comparison of the average activity values obtained in Nigeria cement and other countries of the
world show that those countries with history of high radionuclide solid minerals have activity concentration
far above that of Nigerian cement, while these values agreed with those obtained in other countries.