Assessment of Natural Radioactivity and Associated Radiological Hazards in Soils of Mining Areas in Nasarawa State

Background: Artisanal and small-scale mining activities in Nasarawa State, North Central Nigeria, disturb naturally occurring radioactive materials in soil and may elevate radiation exposure for mining communities. Systematic radiological hazard assessment is urgently needed. Aim: This study assessed natural radioactivity concentrations and associated radiological hazards in soils from active mining areas in Nasarawa State. Methods: Soil samples were collected from 40 sites across five mining areas and five control locations. Activity concentrations of Ra-226, Th-232, and K-40 were measured by gamma spectrometry using a calibrated NaI(Tl) detector. Radiological hazard parameters including absorbed dose rate, annual effective dose, radium equivalent activity, and excess lifetime cancer risk were calculated following UNSCEAR methodology. Results: Mean activity concentrations were 68.4, 89.2, and 412.6 Bq/kg for Ra-226, Th-232, and K-40 respectively in mining areas, compared with global soil averages. Radium equivalent activity in four tin mining sites exceeded the 370 Bq/kg safety limit. Excess lifetime cancer risk for miners was 5.4 times higher than control populations. Conclusion: Mining activities in Nasarawa State elevate radiological hazards to levels warranting mitigation measures. Mandatory radiation monitoring for miners, dust suppression techniques, and remediation of highest-activity waste sites are urgently recommended. Keywords: natural radioactivity, mining, Nasarawa State, radiological hazards, gamma spectrometry.