Assessment of radiation dose rates at the Faculty of Engineering, Ahmadu Bello University, Zaria

This study assessed ambient radiation dose rates within the Faculty of Engineering at Ahmadu Bello University (ABU), Zaria, Nigeria, to evaluate potential radiological hazards and spatial variations. Using a portable gamma spectrometer and GPS device, gamma radiation levels were measured at 20 georeferenced locations, quantifying concentrations of uranium-238 (²³⁸U), thorium-232 (²³²Th), and potassium-40 (⁴⁰K). Results revealed significant spatial variability, with dose rates ranging from 48.63 to 166.63 nGy/h—exceeding the global average of 59 nGy/h (UNSCEAR, 2000). The mean dose rate (123.97 nGy/h) and thorium-232 activity concentrations (mean: 45.73 Bq/kg, peak: 88.42 Bq/kg) indicated localized enrichment, likely due to Precambrian basement rocks (granites/gneisses) underlying the study area. Statistical and spatial analyses identified hotspots with dose rates >130 nGy/h, correlating with geological features. While values remained below international safety limits (ICRP, 1991), prolonged exposure risks warrant attention. The study highlights heterogeneous radiation distribution, influenced by soil composition and lithology, and underscores the need for periodic monitoring, public awareness, and land-use planning to mitigate cumulative exposure. Recommendations include detailed radionuclide assays for hotspots and integration of findings into institutional safety protocols. This work contributes baseline data for environmental radioprotection in academic settings with similar geological profiles.