Evaluation of Radioactivity and Potential Radiological Health Risks of Mined Soils Used as Building Materials in Ijero-Ekiti, Nigeria

Abstract

The utilization of mined soils in building construction has raised serious concerns about radiological hazards to the public due to elevated concentrations of naturally occurring radioactive materials (NORMs). This study assesses the natural radioactivity levels and potential radiological health risks associated with mined soils commonly used as building materials in Ijero-Ekiti, a major mining community in Southwestern Nigeria. Gamma spectrometry analysis was performed on thirty (30) randomly sampled mined soil samples using a high-purity Germanium (HPGe) detector to determine activity concentrations of the radium-226 (226Ra), uranium-238 (238U), thorium-232 (232Th), and potassium-40 (40K). Radiological models based on these measured activity concentrations were used to evaluate potential health risk indicators, including hazard indices (Hex and Hin), Annual Gonadal Dose Equivalent (AGDE), annual effective dose (AEDout and AEDin), radium equivalent activity (Raeq), and excess lifetime cancer risk (ELCR). The average activity concentrations of 226Ra, 238U, 232Th, and 40K in the samples were 512.28 ± 26.76, 241.26 ± 12.55, 31.07 ± 3.56, and 2808.01 ± 148.52 Bq/kg, respectively. Radionuclide concentrations and calculated health risk indicators exceeded global average values reported by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) and recommended safe limits set by the International Atomic Energy Agency (IAEA). These findings indicate elevated ionizing radiation levels in the samples, posing potential radiological health risks to exposed residents. To address these concerns, stringent policies, public awareness, further research, and safer building materials are recommended.