Investigation of Natural Radioactivity Levels and Evaluation of Radiation Hazards in Residential-Area Soil Near a Ras Tanura Refinery, Saudi Arbia

One of the oldest oil refineries in the Middle East is located south of Ras Tanura in eastern Saudi Arabia, Arabian Gulf. Naturally occurring radionuclides may be associated with the extraction processes of oil and gas. Therefore, the activities concentrations of U-238, Ra-226, Th-232, K-40, and Cs-137 in soil samples near Ras Tanura refinery were measured using the gamma ray spectrometric technique. The mean activity concentrations of the radionuclides U-238, Ra-226, Th-232, 40K, and 137Cs were 39.0 +/- 4.8 Bq/kg, 23.2 +/- 1.4 Bq/kg, 7.73 +/- 1.2 Bq/kg, 278 +/- 9.8 Bq/kg, and 1.42 +/- 0.5 Bq/kg, respectively. Radiation hazard indices were calculated to evaluate the radiological risk for the public and environment. The results show that the mean values of radium equivalent activity (Ra-eq) and gamma absorbed dose rate (D) in air, annual effective dose equivalent (E), and external radiation hazard indices for analyzed samples were lower than the recommended limit by the United Nations Scientific Committee on the Effect of Atomic Radiation. This study is the first to evaluate the radiological impacts in the investigation area. Accordingly, the present study could be considered a baseline for natural radioactivity levels in soil near a refinery area in Ras Tanura.