ENVIRONMENTAL RISK ASSESSMENT OF ZINC, CADMIUM, COPPER AND LEAD IN SOIL AT VEHICLES MAINTENANCE SITE, PORT HARCOURT, NIGERIA.

This study assessed the environmental risks associated with zinc (Zn), cadmium (Cd), copper (Cu), and lead (Pb) contamination in soils from vehicle maintenance sites inChoba, Port Harcourt. Soil samples were collected from selected vehicle maintenance locations and analyzed for heavy metal concentrations using standard analytical procedures. The results revealed varying concentrations of the investigated metals across the sampling points. Zinc recorded concentrations ranging from 52.35 to 664.50 mg/kg, cadmium ranged from 0.60 to 8.65 mg/kg, copper ranged from 5.30 to 716.99 mg/kg, while lead ranged from 1.40 to 275.00 mg/kg. The highest concentrations of Zn, Cd, Cu, and Pb were observed at sample point SH, indicating a major contamination hotspot within the study area. Comparison with permissible soil quality standards showed that several sampling points exceeded recommended limits, particularly for cadmium, copper, lead, and zinc. The elevated concentrations were attributed to anthropogenic activities such as waste oil discharge, battery disposal, tyre wear, welding, and spray-painting operations. The findings suggest that prolonged vehicles maintenance activities have significantly impacted soil quality within the area. The study concludes that the soils around the investigated maintenance sites are moderately to heavily contaminate and may pose environmental and human health risks. Proper/Smart waste management practices, environmental monitoring, and regulatory enforcement are therefore recommended to minimize further heavy metal accumulation in the study area.