Abstract
It is important to measure the radionuclide concentrations in red soil to determine the health effect and to protect the environment. The red soil regions located in Qassim province, Saudi Arabia were determined. Thirty red soil samples were collected from three regions (Al Bi'ithah, Dremeha and Al Bukaireyah). Gamma-ray spectrometry using NaI (Tl) detector was used to measure the radionuclides of 226Ra, 232Th and 40K. The average (range) of activity concentration of 226Ra was 10.0 (9.3–11.6) Bq/kg, 7.3 (6.6–8.4) Bq/kg and 19.4 (15.9–22.7) Bq/kg in Al Bi'ithah, Dremeha and Al Bukaireyah, respectively. For 232Th, the average values of radioactivity concentration were 11.8 (7.6–13.0), 6.3 (5.1–7.3) and 19.1 (17.8–20.7) in Al Bi'ithah, Dremeha and Al Bukaireyah, respectively. In addition, the average radionuclide concentration of 40K was 74.5 (71.2–78.3), 67.3 (57.6–77.4) and 94.3 (59.6–101.6) in Al Bi'ithah, Dremeha and Al Bukaireyah, respectively. Next, the comparison between radionuclide concentrations in this study and other published papers in the world was done. In addition, radiation hazard parameters were estimated. The maximum values of the radium equivalent and absorbed dose rate were 63.6 Bq/kg and 30.0 nGy/h, respectively. These values are lower than the international limit (370 Bq/kg and 65 nGy/h). Furthermore, the annual effective gamma doses and the lifetime hazards of cancer were lower than the international limit. The external hazard index (Hex), internal hazard index (Hin) and representative level index (Iγr) were found to be less than the acceptable limit of unity. Therefore, the study area is still in the zones of normal radiation level, which leaves the red soil radioactivity there less a threat to the environment as well as the human health.