Assessment of Natural Radionuclides Concentrations and Radiological Hazards from Soil Samples in Alabata and Its Environs, Ogun State, Southwestern Nigeria

The natural occurring level of radioactivity in any soil is one of the main causes of external gamma exposure. The activity concentrations of natural radionuclides from soils in granitic area of Alabata, southwest Nigeria were determined with the aim of knowing the levels and evaluating the radiological hazards. Soil samples were collected and analysed by gamma-ray spectrometry method utilizing NaI scintillation detector. Results show that the ranges (and the conforming average values) of the estimated activity concentrations for 238 U, 232Th and 40K are 6.46 0.00 to 66.57 15.05; 211.56 96.10 to 6.46 0.00, and 211.56 ± 96.10 to 470.02 91.28 Bq/Kg, respectively. 238U was mostly below detection limits (BDL) All the estimated radiological hazards were observed to be within the threshold limit of 370 Bq/kg, 60 nGy/h per UNSCEAR standards, 1 mSv/yr, 1.45 × 10⁻³, and 1 for radium equivalent activity, absorbed dose rate, effective dose, excess life cancer risk, and external and internal hazard index respectively as recommended by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), Specifying that 238U was mostly below detection limits (BDL). Further investigation into the levels and radiation exposures of quarry soils within the vicinity of the study area is highly suggested.