Evaluation of Radionuclide Contents in the Soil of Oloru Town, Moro Local Government Area, Kwara State, Nigeria

Abstract

Naturally occurring radionuclides in soil, particularly ²²⁶Ra, ²³²Th, and ⁴⁰K, are a recognized public-health and environmental protection concern, as soil serves as a major reservoir and transfer pathway to plants, water, and humans via external irradiation and ingestion. Localized radiological data for Oloru Town, Moro Local Government Area, Kwara State, Nigeria, an agrarian community with potential soil–groundwater interaction, remain limited. This study therefore evaluated ²²⁶Ra, ²³²Th, and ⁴⁰K concentrations in Oloru soils and estimated the associated radiological hazard indices and population dose. 50 soil samples were collected across ten stratified locations. A well calibrated gamma spectrometry detector was used for the assessment of the radionuclide contents. Absorbed dose rate, annual effective dose equivalent, radium equivalent activity, external and internal hazard indices, gamma representative index, and excess lifetime cancer risk (ELCR) were subsequently estimated. It was observed that ⁴⁰K was the dominant radionuclide (347.2–654.8 Bqkg^-1), while ²²⁶Ra (8.87–22.00 Bqkg^-1) and ²³²Th (4.50–20.42 Bqkg^-1) remained below world averages. Absorbed dose rate (27.73–38.94 nGyh^-1), annual effective dose (0.034–0.048 mSvy^-1), radium equivalent activity, hazard indices, gamma index, and ELCR (0.119–0.167 ×10^-3) were all well below internationally recommended limits at every location. The soils of Oloru Town pose no significant radiological health risk from external exposure, supporting continued safe habitation and agricultural use, and the findings establish essential baseline data for future environmental radiation monitoring and land-use planning in the community and comparable settlements.