Assessment of radiological parameters and metal contents in soil and stone samples from Harrat Al Madinah, Saudi...

The current work deals with measurement and distribution of natural radionuclides for twelve (12) soil and fifteen (15) stone samples collected from Harrats Al Madinah in western region of Saudi Arabia. Two methods were used in this investigation gamma-ray spectrometer (GRS) and X-ray fluorescence (XRF).The activity concentrations of radionuclides (²²⁶Ra, ²³²Th and ⁴⁰K) were measured using γ-ray spectrometer NaI(Tl) model (A320) made in the U.S.A. The average values of the concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K were 37.5 ± 0.1, 28.0 ± 0.5 and 300.6 ± 1.7 Bq/kg respectively. The obtained results show that the mean radium equivalent activity, annual effective dose, external and internal hazard indices and radiation level index were 100.67 BqKg^-1, 55.63μSv, 0.27, 0.37 and 0.73 respectively. The results were compared with the recommended limits in the literature from other locations and with the global allowable limits recommended by International Commission on Radiological Protection and United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). The obtained results are concordant with the magnitude of safe criteria and exposure risks which were recommended in public papers. The current study is considered as the first baseline data for the natural radioactivity and metal contents measured by X-ray fluorescence method in the Harrat Al Madinah city.