In southwestern Nigeria, the increase in informal mining activities has raised environmental and public health concerns due to the potential mobilization of naturally occurring radioactive materials (NORMs) into surrounding ecosystems. In this study, 30 soil samples and 60 mine tailings were collected and analyzed to determine the activity concentrations of NORMs ( 40 K, 238 U, and 232 Th). Gamma spectrometry with a well-calibrated CsI(Tl) detector was used. Spatial distribution maps were generated via geostatistical interpolation techniques. The radiological health risks associated with NORMs in the study area were assessed. The mean activity concentrations of 40 K, 238 U, and 232 Th were 465.9 ± 267.5 Bq kq −1 , 30.3 ± 9.1 Bq kg −1 , and 48.7 ± 13.2 Bq kg −1 , respectively, in the soil samples, whereas the values were 607.3 ± 651.8 Bq kg −1 for 40 K, 29.5 ± 24.6 Bq kg −1 for 238 U, and 53.0 ± 34.5 Bq kg −1 for 232 Th in the mine tailings. Compared with soil, mine tailings present slightly higher activity concentrations of radionuclides. Geospatial maps of the study area reveal distinct hotspots with elevated activity concentrations of radionuclides, particularly in areas in close proximity to mining sites. The results of the radiological health risk parameters evaluated in this study show that while most locations fall within internationally recommended safety limits, certain areas (with high activity concentrations of NORMs) can pose potential radiological health risks to local populations through prolonged exposure. There is a need for continuous environmental monitoring and the implementation of safety guidelines in the study area to mitigate radiological hazards associated with artisanal mining.
Fasanmi et al. (Mon,) studied this question.