Radionuclide Assessment and Estimation of Radiological Indices in Groundwater Samples from Selected Mining Sites in Osun State, Southwestern Nigeria

Abstract

The radiological contamination of groundwater sources near mining sites has become a significant environmental concern due to the potential risks posed by elevated levels of naturally occurring radioactive materials (NORMs). The study hereby assesses the radioactivity concentrations of 40K, 238U and 232Th in seventy-eight (78) groundwater samples collected from mining sites in the gold belt region of Osun State, Nigeria, using NaI(Tl) based gamma spectrometer and also estimates their associated radiological indices. The results indicated that the mean activity concentrations of all radionuclides exceeded the World Health Organisation's permissible limits of 1.0 Bq/L, raising significant concerns regarding the radiological safety of the water from the area under investigation. The radium equivalent values of 456.75 Bq/L and 272.87 Bq/L were obtained at Olowu and Iganga mining sites, respectively, where contamination levels were highest. The heightened exposure risks underscore the need for urgent interventions to protect public health and the environment in communities affected by mining activities.