Assessment of Natural Radioactivity Levels and Radiological Hazards of Cement in Iraq

摘要

Eight samples of cement were collected from different commercial factories (Al-Koufa, Al-Basra, Al-Najaf and Kerkouk factories) located in Iraq. They were analyzed using a gamma ray spectroscopy system. The activity concentrations of ~(226)Ra, ~(232)Th and ~(40)K were ranged from 5.8 to 43.17 Bq kg~(-1), from 0.99 to 55.79 Bq kg~(-1) and from 53.28 to 185.34 Bq kg~(-1), respectively. The potential radiological hazards were assessed by calculating the radium equivalent activity (Ra_(eq)), the indoor absorbed gamma dose rate (D), the annual effective dose equivalent (AEDE), the alpha index (I_α), the gamma index (I_γ), and the external hazard (H_(ex)) and internal hazard (H_(in)) indices. The highest value of Ra_(eq) is estimated of 101.36 Bq kg~(-1), which is significantly less than the upper limit of 370 Bq kg~(-1). The estimated maximum value of the absorbed gamma dose rate of 54.71 nGy h~(-1) is within the world average value of 55 nGy h~(-1), and the annual effective dose equivalent in the studied samples were 0.05 (outdoor), 0.18 (indoor) mSv y~(-1), which is lower than the recommended limit reported in the UNSCEAR (2000). The values of the hazard indices were below the recommended levels; therefore, the study shows that the measured radioactivity for cement does not pose as significant source of radiation hazard and is safe for use in the construction of dwellings.