Assessment of radiological hazards of some selected portland cement used in Nigeria

This work assess through analysis, the natural radionuclide level and the associated radiological hazards of some selected Portland cement used in Nigeria The natural radionuclide content of Portland Cement widely used in Nigeria were measured using a highly shielded Canberra Na(Tl) detector, a type of gamma-ray spectrometry. A total of 15 samples from 5 batches of the product were analyzed. The mean value of 226Ra, 232Th and 40K concentrations determined were 33.85 ± 9.79 Bqkg-1, 20.05 ± 3.93 Bqkg-1 and 78.01 ± 25.01 Bqkg -1 respectively, being lower than the permissible global values of 52.2 Bqkg -1, 41.0 Bqkg-1 and 230.0 Bqkg-1 respectively by UNSCEAR. On the basis of hazard indices, internal hazard index of 0.2766, external hazard index of 0.1850 were obtained for the product and are fund to be much lower than unity. The absorbed dose rate of 31.0030nGyh-1 and the annual effective dose rate of 0.1521mSvy-1 are much below the recommended standard by UNSCEAR. All the cement sample analyzed met the safety criteria by UNSCEAR and hence do not pose any radiological hazards to human health.