Asian Journal of Advances in Research

Automobile repair activities in urban environments contribute significantly to heavy metal accumulation in surface soils, yet detailed geochemical evidence remains limited for many cities in southern Nigeria. This study investigated the concentration levels and spatial distribution of cadmium (Cd), chromium (Cr), lead (Pb), iron (Fe), nickel (Ni), and zinc (Zn) in soils from selected automobile mechanic workshops in Asaba, Delta State. Composite surface soil samples (0–15 cm) were collected from four active workshop locations and a control site within Dennis Osadebay University. Samples were digested using a nitric–perchloric acid mixture and analysed using atomic absorption spectrophotometry (AAS). Mean metal concentrations in workshop soils ranged from 5.34–9.01 mg/kg for Cd, 5.32–10.36 mg/kg for Cr, 21.81–52.11 mg/kg for Pb, 23.17–31.85 mg/kg for Fe, 6.80–14.37 mg/kg for Ni, and 18.06–24.46 mg/kg for Zn, compared with substantially lower values at the control site. Cadmium concentrations at all workshop locations exceeded WHO and NESREA guideline limits, while lead exceeded permissible levels at the Mami Market site. Although Cr, Ni, and Zn remained within regulatory thresholds, their enrichment above background levels indicates continuous anthropogenic input. The findings highlight progressive modification of urban soil geochemistry due to automobile repair activities and underscore the need for improved waste management and routine environmental monitoring in mechanic-workshop environments.