Geospatial assessment of activity concentrations of natural radionuclides and absorbed dose rates in gidan-kwano, minna, nigeria using airborne radiometric data

Abstract

This study assessed the spatial distribution of natural radionuclides and the associated absorbed dose rates in Gidan-Kwano, Minna, Niger State, Nigeria, using airborne radiometric data acquired from the Nigerian Geological Survey Agency (NGSA). Activity concentrations of ²³⁸U, ²³²Th, and ⁴⁰K were determined, and geospatial contour and isodose maps were generated. Absorbed dose rates ranged from 18 to 69 nGy/h (mean: 32 nGy/h), below the global reference of 59 nGy/h, indicating low radiological risk. Pearson correlation analysis revealed a strong positive correlation for ⁴⁰K (R = 0.93), a moderate correlation for ²³²Th (R = 0.62), and a weak correlation for ²³⁸U (R = 0.08), suggesting ⁴⁰K largely drives spatial variability despite a lower dose contribution. Comparison with previous in-situ measurements showed weak agreement, reflecting methodological and spatial-scale differences. The findings establish a regional radiological baseline and demonstrate the utility of airborne surveys for environmental monitoring and radiation protection planning.