Evaluating the level of 226Ra, 232Th and 40K in different building materials

Abstract

This study evaluates the levels of ²²⁶Ra, ²³²Th, and ⁴⁰K in various building materials, including brick, cement, sand, gravel, and gypsum, sourced from Al-Shatra in the Dhi-Qar Governorate of Iraq. Measurements were conducted using a NaI (Tl) detector, which is an effective tool for gamma-ray spectrometry. The average activity concentrations measured were 19.70 ± 6.7 Bqkg⁻¹ for ²²⁶Ra, 20.14 ± 3.3 Bqkg⁻¹ for ²³²Th, and 232.24 ± 91 Bqkg⁻¹ for ⁴⁰K. The calculated mean radium equivalent activity was found to be 66.63 Bqkg⁻¹, which is below the internationally accepted threshold of 370 Bqkg⁻¹. Both the internal hazard index (Hin) and the external hazard index (Hex) were determined to be less than unity (<1), in accordance with the safe levels recognized by UNSCEAR. Additionally, the average values for the absorbed dose rate (nGyh⁻¹), indoor annual effective dose (mSvy⁻¹), outdoor annual effective dose (mSvy⁻¹), and gamma-ray exposure rate (μRh⁻¹) were estimated to be 59.09, 0.29, 0.07, and 138.83, respectively. These parameters are within acceptable limits when compared to the world-permitted values. Therefore, all types of building materials assessed in this study are considered safe and do not pose a significant threat to public health.