UNIHEZ JOURNAL OF CONTEMPORARY RESEARCH

Uncontrolled waste dumpsites in rapidly urbanizing regions are complex environmental systems where chemical and radiological hazards coexist but are often assessed separately, limiting understanding of cumulative exposure and long-term health risks. This study presents an integrated spatial assessment of background ionizing radiation (BIR) and heavy metal contamination in soils around the Ariaria waste dumpsite, Nigeria, with the aim of developing a unified radiological–toxicological risk framework. In situ gamma radiation measurements were conducted using a calibrated Geiger–Müller survey meter, while soil samples were analysed for elemental composition using X-ray fluorescence spectrometry. Radiological indices, including absorbed dose rate, annual effective dose equivalent (AEDE), and excess lifetime cancer risk (ELCR), were calculated using standard models. Heavy metal concentrations were evaluated against international guideline limits, and spatial patterns were analysed to identify contamination variability. Results show that the mean absorbed dose (≈193.3 nGy h⁻¹) exceeds the global average of 89 nGy h⁻¹, indicating enhanced radiation from radionuclide-bearing wastes. Although AEDE (≈0.30 mSv y⁻¹) remains within recommended public exposure limits, ELCR (≈1.03 × 10⁻³) exceeds global reference values, suggesting elevated long-term cancer risk. Geochemical analysis reveals that chromium, uranium, thorium, nickel, and cobalt exceed regulatory thresholds, while cadmium, lead, zinc, and arsenic remain within permissible limits. Spatial patterns indicate heterogeneous contamination driven by waste composition and subsurface processes. Overall, the co-occurrence of radiological and chemical contaminants highlights a chronic, multi-pathway exposure scenario with potential long-term health implications. These findings emphasize the need for integrated monitoring, improved waste management, and targeted remediation strategies.