Evaluation of Natural Radioactivity and Associated Radiological Risks of Farmland Soil: A Study of a Campus Farmland of Osun State University, Nigeria

Assessment of activity levels of radionuclides that exist in nature in agricultural farmland soils is very crucial because of the deleterious effects that gamma radiation can have on humans, once exposed. This study determined the radioactivity levels of 232Th, 238U, and40K (radionuclides that exist in nature) in 60 soil representatives gathered from a Teaching and Research Farm of Osun State University located in Ejigbo, Ejigbo Local Government Area of Osun State, Nigeria using gamma-ray spectroscopy equipped with Caesium Iodide (CsI) scintillation detector. It also evaluated indices of the radiological hazard consisting of annual effective dose, gamma dose rate, external and internal risk indices, activity of radium equivalent, annual gonadal dose equivalent, and concentration index of gamma activity. The evaluated mean values of the radioactivity levels of 40 K and 232Th were below the recommended global averages. The computed mean value of the measured 238U radioactivity levels is greater than the value for the worldwide average by a factor of 0.11. All the evaluated values of the radiological risk of the appraised radionuclides were below the globally acceptable limits. Also implemented in this study is the correlation analysis that establish the relationship between the measured radioactivity levels and the evaluated radiological risks. Correlation analysis results estalished that all the variables are positively and strongly correlated. The soil samples under consideration were considered to be safe for agricultural activities since it does not cause any radiation risk to the human population.