Radionuclide content of local and imported cements used in Egypt.

The activity concentrations of natural and artificial gamma-ray emitting radionuclides in local and imported cement have been investigated during the period from 2000 to 2003 using a 50% HPGe gamma-spectroscopy system. The total numbers of local and imported samples were 29 and 8, respectively. The results showed a low activity concentration of (137)Cs in both the local and imported samples. The only exception was found in one imported Portland cement (2.8 +/- 0.2 Bq kg(-1)) and one local blast furnace slag cement (1.9 +/- 0.3 Bq kg(-1)). The average activity concentrations of (226)Ra, (232)Th and (40)K in local cement were 33 +/- 17, 14 +/- 2.4 and 45 +/- 26 Bq kg(-1), respectively, whereas those in imported cement were 27 +/- 7, 8 +/- 7 and 134 +/- 22 Bq kg(-1), respectively. The results showed that blast furnace slag cement contains the highest level of natural radioactivity, whereas white cement contains the lowest levels. The measured activity concentrations of the detected radionuclides were compared with other measurements carried out in Egypt and elsewhere. Radium-equivalent activities were also calculated to assess the radiation hazards arising from using such material in the construction of dwellings. Generally, the radium-equivalents of the analysed samples were smaller than the guideline limit of 370 Bq kg(-1).