Radiological Risk Assessment of Radon Gas in Bricks Samples in Iraq

Naturally occurring radioactive radon gas is produced from radioactive decay of naturally radioactive element radium and emits alpha particles. The radon gas is the main source of natural background radiation that contributes to about more than 60% of the annual radiation dose to humans on Earth. In this research, radon concentrations (Rn-222) in brick samples that are available in Iraqi markets were measured using solid state nuclear track (CR-39). Also, uranium-238 (U-238), radium-226 (Ra-226) were calculated in all samples under study together with some radiation parameters such as exhalation of radon gas rate (F-O), annual effective dose (D-Rn), and excess lifetime cancer risk (ELCR). It was found that, the average value of Rn-222, U-238, and Ra-226 concentrations in studied samples were 48.75 +/- 10.61 Bq/m(3), 0.084 +/- 0.02 ppm, and 115.57 +/- 29.60 mBq/kg, respectively. Also, it was found that the average of each of F-O, D-Rn, and ELCR were 27.54 +/- 5.99 mu Bq/m(2).h, 0.88 +/- 0.17 nSv/y, and (3.01 +/- 0.65) x 10(-3), respectively. After data analysis, the resulted data were examined and compared with the global average and the permissible limits which recommended by the international scientific agencies such as International Commission on Radiological Protection (ICRP 2010), United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR 2017), Organization for Economic Cooperation and Development (OECD 2009). It was found that radiation levels from brick samples used in local markets for most models fell within the permissible limits and may not cause any danger to human beings.