Radiological hazard assessment of soil from Kasik oil refinery, Nineveh, Iraq

Abstract

This study explored soil samples in a depth about 10–15 cm, 20 Soil samples were collected systematically from various locations to ensure a comprehensive assessment of the site within Kasik oil refinery, Nineveh Governorate, Iraq, whereby the determination of three natural radionuclides' specific activities was carried out via A p-type coaxial HPGe γ-ray spectrometer, manufactured by CANBERRA, USA. Natural radioactivity in soil is a significant factor for assessing environmental radiation exposure and potential health risks. The 226Ra, 232Th, and 40K radionuclides' mean specific activities in the soil samples were in the 13.10–33.43 Bq/kg, 10.58–22.76 Bq/kg, and 104.90–442.16 Bq/kg ranges, respectively, with overall means of 21.44 Bq/kg, 15.96 Bq/kg, and 255.50 Bq/kg, which are within the worldwide mean levels. The mean radium-equivalent activity (Raeq) was 63.94 Bq/kg, and thus below the 370 Bq/kg international limit. All of the samples' representative level index (Iɣ) and internal and external hazard indices (Hin and Hex) were below the limit of unity, indicating low radiation hazards. The absorbed dose rate resulting from the three primordial radionuclides was in the 19.92–41.46 nGy/h range (mean: 30.20 nGy/h), with an annual effective dose of 0.04 mSv/y. The mean excess lifetime risk of cancer was found to be 0.15 × 10⁻³, and thus under the 0.29 × 10⁻³ world average. The study's results indicate that the natural radionuclides' measured specific activities in the soil samples are below the world recommended values, suggesting that the investigated area is safe in terms of radiological health risks.