ABSTRACT
The widespread growth of open dumpsites in Nigeria, fueled by insufficient waste management systems, presents serious threats of heavy metal pollution to soil, water, and public health. This research investigated heavy metal concentrations in soils from two operational dumpsites in Benin City, Nigeria, and explored their potential environmental and health impacts. Soil samples were gathered from the Oluku and Ikhueniro dumpsites at three depths (0–10 cm, 10–20 cm, and 20–30 cm) and tested for lead (Pb), cadmium (Cd), chromium (Cr), and nickel (Ni) using Atomic Absorption Spectrophotometry (AAS). Key physicochemical properties, such as pH, electrical conductivity (EC), cation exchange capacity (CEC), and moisture content, were also analyzed. Findings indicated slightly acidic soils (pH 5.65–6.05), moderate salinity (EC: 120–206 µs/cm), and CEC values (5.16–5.96 meq/100g) that affected metal retention. Most heavy metal levels were within the National Environmental Standards and Regulation Enforcement Agency (NESREA) guidelines: Pb (1–2 mg/kg), Cr (2–19 mg/kg), and Ni (5–14 mg/kg). However, Cd surpassed the allowable limit (7 mg/kg vs. 3 mg/kg) in one instance. Statistical analysis demonstrated significant adherence to standards for Pb, Cr, and Ni (p < 0.001), but Cd levels did not significantly differ from permissible limits (p = 0.286), suggesting localized contamination risks. Although current pollution levels are generally minimal, the enduring presence of heavy metals and the reuse of dumpsites for farming pose long-term risks to food safety and public health. The study emphasizes the necessity of proactive strategies, including improved waste segregation, phytoremediation, community awareness, and ongoing monitoring, to reduce these risks. This research highlights the importance of stronger regulatory enforcement and additional studies to address gaps in long-term impact evaluations and remediation effectiveness.
