Radioactivity and Radiation Hazard Indices Assessment for Phosphate Rock Samples from Al-Jalamid, Turaif, Umm Wu’al, and As-Sanam, Saudi Arabia

Abstract

In this study, the activity concentration of 235U, 40K, 238U, 226Ra, and 232Th in phosphate rock found in the Kingdom of Saudi Arabia has been measured by gamma-ray spectrometry. Phosphate is extracted from the northern region in Saudi Arabia and widely used in agriculture as fertilizers as well as in the chemical industry. The average activity concentration of 235U, 238U, 226Ra, 232Th, and 40K has been measured as (10.34 ± 1.49 Bq kg−1, 260.99 ± 19.68 Bq kg−1, 242.33 ± 2.74 Bq kg−1, 3.42 ± 0.94 Bq kg−1, and 47.50 ± 3.03 Bq kg−1) for Al-Jalamid phosphate rock ores, respectively; (46.10 ± 2.61 Bq kg−1, 1028.31 ± 36.88 Bq kg−1, 989.98 ± 6.41 Bq kg−1, 13.75 ± 1.68 Bq kg−1, and 51.93 ± 3.82 Bq kg−1) for Turaif phosphate rock ores, respectively; (63.60 ± 3.33 Bq kg−1, 1353.25 ± 41.58 Bq kg−1, 1304.29 ± 7.70 Bq kg−1, 13.45 ± 1.64 Bq kg−1, and 40.26 ± 3.67 Bq kg−1) for Umm Wu’al phosphate rock ores, respectively; and (13.83 ± 1.59 Bq kg−1, 318.72 ± 21.78 Bq kg−1, 350.50 ± 3.14 Bq kg−1, 5.01 ± 1.13 Bq kg−1, and 42.15 ± 3.02 Bq kg−1) for As-Sanam phosphate mines, respectively. The radiological parameters (gamma index, absorbed dose, outdoor and indoor annual effective dose, and total excess lifetime cancer risk (ELCR)) have also been calculated to assess the health hazards. The radiation indices, effective dose, and ELCR have been found high in all samples corresponding to International Commission on Radiological Protection (ICRP) safety limits, which reflects a radiological health risk for workers and population. The X-ray diffraction (XRD) analysis confirms the concentration of dominant elements like fluorapatite (Ca5(PO4)3F), dolomite (CaMg (CO3)2), and minor traces of quartz (SiO2) and calcite (CaCO3). The elemental concentration of CaO, Al2O3, P2O5, SiO2, MgO Al2O3, and Fe2O3 has been measured by X-ray fluorescence (XRF) technique.