Pollution profile, ecological and health risk assessment of trace metals in soils of auto mechanic workshops at Gombe metropolis, Gombe State, Northeastern Nigeria

This study was conducted to assess the pollution profile, ecological and health risks associated with trace metals (Cr, Mn, Cu, Ni, Cd and Pb) in soils in the vicinity of auto mechanic workshops in Gombe metropolis, Nigeria. Soil samples were collected at depths of 0–15 cm and analyzed after acid digestion using an atomic absorption spectrophotometer (AAS). The data collected were analyzed for descriptive and inferential statistics. The mean concentration of trace metals (mg kg −1 ) ranged Cr (0.14–12.7), Mn (1.46–32.65), Cu (3.22–183.80), Ni (2.47–138.50), Cd (0.23–14.50) and Pb (1.39–135.40). The result showed that metals were highly accumulated in the following trend: Cu > Ni > Pd > Mn > Cd > Cr. Correlation, principal component analysis (PCA) and hierarchical clustering analysis (HCA) revealed that the major source of pollution might be linked to the anthropogenic activities at auto mechanic workshops. Pollution indices studies showed that soil samples were highly contaminated with Cu, Ni, Cd and Pb. The ecological risk assessment is classified under high to serious ecological risk, and cadmium contributes 88–92% of the total potentially ecological risk. The total hazard index (HI) for ingestion was > 1 for children, which indicated a non-carcinogenic health risk effect for children. The cancer risk (CR) values for ingestion and dermal pathways exceeded the threshold value (1 × 10 −6 to 1 × 10 −4 ) for both children and adults, indicating possible cancer development. The study concludes that the activities at the mechanic workshops contaminated the soil and eventually pose threat to humans, suggesting adequate attention should be given to the risk of these trace metals in the study areas.