Radiological impact of primordial radionuclides and radon rates in rock-based building materials: Kurdistan region of Iraq

The present study aimed to assess primordial radionuclides and radon's specific activities as found in the Iraqi Kurdistan Region's rock samples, which are used as building materials. For this purpose, NaI (Tl) and RAD-7 detectors were employed. The results indicated that ²²⁶Ra, ²³²Th, and ⁴⁰K's average specific activities are 18.3 ± 8.45, 20.04 ± 4.7, and 179.3 ± 47.4 Bq kg⁻¹, respectively. This suggests that there are no significant radiological impacts or emissions in the area; therefore, it is possible to use the rocks for building material purposes. Additionally, the measured radiation hazard index values fall within the range specified by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), except for the absorbed dose rate's average value, which slightly exceeded the safety standard. ²²²Rn activity's average value is about 43.1 ± 6.51 Bq m⁻³, which is below the 200 -600 Bq m⁻³ threshold value. Meanwhile, the average surface and mass exhalation rates were 1.94 ± 0.97 Bq m⁻² d⁻¹ and 0.075 ± 0.045 Bq kg⁻¹ d⁻¹, respectively. Furthermore, the average radon emanation coefficient was 2.48 ± 0.85. The study utilized various statistical analyses to assess the distribution and relationships of the rock sample-based natural radionuclides (²²⁶Ra, ²³²Th, ⁴⁰K) and ²²²Rn activity concentration. The Shapiro–Wilk test confirmed normal distribution for the data, while skewness and kurtosis provided insights into the distribution characteristics. Pearson correlation analysis revealed a strong correlation between ²²²Rn and ²²⁶Ra, while other radionuclide pairs showed weaker relationships. Principal Component Analysis (PCA) explained 90.2% of the variance in the dataset, highlighting the significance of the primary component. Finally, spatial distribution maps for the study area were created in terms of the radionuclides' specific activity, radiological hazard indicators, and radon concentrations. This study's results offer insights into the future radiological environment of the region.