OKOH VICTORIA OSAS

This study evaluates heavy metal contamination in soils and earthworms (Aporrectodea longa) across three distinct sites—a botanical garden, an automobile repair workshop, and an industrial zone—to assess site-specific pollution impacts. Soil and earthworm samples were analyzed for zinc (Zn), copper (Cu), manganese (Mn), cobalt (Co), lead (Pb), cadmium (Cd), nickel (Ni), and iron (Fe). Results revealed stark contrasts: the industrial zone exhibited the highest contamination, with Cd averaging 0.2700 mg/kg in soil (peaking at 0.5250 mg/kg) and 0.01500 mg/kg in earthworms, exceeding regulatory thresholds. The automobile workshop showed elevated Pb (0.02100 mg/kg in soil) linked to vehicular emissions, while the botanical garden had relatively lower metal levels (Zn: 1.370 mg/kg in soil), though earthworms still accumulated significant Fe (3.342 mg/kg) and Cd (0.01450 mg/kg). Earthworm bioaccumulation patterns mirrored soil contamination, with industrial earthworms retaining hazardous Pb (0.03150 mg/kg) and Cd, underscoring their role as bioindicators. The automobile workshop’s earthworms exhibited suppressed metal uptake (Zn: 0.3600 mg/kg vs. soil Zn: 1.661 mg/kg), suggesting behavioral avoidance or toxicity effects. Conversely, botanical garden earthworms demonstrated moderate bioaccumulation despite lower soil pollution, hinting at atmospheric deposition. These findings highlight the industrial zone as a critical hotspot, with Cd posing severe ecological and human health risks due to its carcinogenic potential. The study advocates for urgent remediation in industrial areas, stricter regulation of automotive waste, and expanded use of earthworms in pollution monitoring. By linking land use to metal bioavailability, this research provides actionable insights for urban planning and environmental policy.