Spatial Patterns of Gamma Radiation and Radiometric Anomalies at Municipal Dumpsites in Uyo and Eket, Akwa Ibom State, Nigeria

Abstract

Municipal solid-waste dumpsites may accumulate naturally occurring radioactive materials (NORMs) and technologically enhanced NORMs (TENORMs), creating spatially variable environmental radiation. This study evaluated gamma-radiation patterns at open dumpsites in Uyo and Eket, Akwa Ibom State, Nigeria, using a portable Geiger–Müller REED R8008 scanner. Count rate and dose-rate equivalents were measured along parallel profiles at 5 m station intervals, with local control backgrounds of 3.3–3.5 CPM. Based on the tabulated measurements, Eket recorded approximately 18.06–44.82 CPM, corresponding to 0.181–0.448 µSv h⁻¹, whereas Uyo recorded approximately 9.96–53.88 CPM, corresponding to 0.10–0.539 µSv h⁻¹. Spatial maps indicate relatively compact, core-centred anomalies at Eket and broader zones of elevated radiation at Uyo. The observed distributions coincide with waste-accumulation areas and are considered in relation to the permeable sands of the Benin Formation and the shallow hydrogeological setting. Although the survey characterises surface and near-surface gamma radiation rather than subsurface radionuclide transport, the results establish a site-specific radiometric baseline for the two dumpsites. The study supports the use of repeat ground radiometric surveys, together with complementary hydrogeological and geophysical monitoring, to evaluate temporal changes and spatial persistence of radiometric anomalies at municipal solid-waste disposal sites in the Niger Delta.