The Impact of Auto Mechanic Junk on Soil and Groundwater Physicochemical Properties in Selected Sites in Port-Harcourt, Nige Delta, Nigeria

The proliferation of auto-mechanic sites near houses within cities has made it necessary to study the impact of car assembly and disassembly activities on the adjoining soil and water. Thus, this study hypothesizes that pollutants from auto-mechanic junk (waste) will adversely affect the soil and water. We chose some auto mechanic sites at three locations in Port Harcourt. Three soil and water samples were randomly collected from the three sites (Ikokwu, Elekahia, and Mile 3 auto parts sites) within each location (n = 18) using soil augur and water jar, respectively. We sent the samples to the laboratory for the analysis of pH. Cadmium, Lead, Chromium, Iron, and Manganese using the atomic absorption spectrophotometric method (AAS) after digesting 2 g soil samples and immersing in nitric acid (HNO3). The ANOVA result reveals no significant difference in heavy metal concentration between the surface and sub-surface soils (F1, 28, 0.02, P = 0.88). Nevertheless, the surface soil has a higher concentration of metals than the sub-surface soils. Iron has the highest concentration in surface and sub-surface soils, followed by Chromium, Manganese, Lead, and Cadmium. At the same time, cadmium has the lowest concentration of all metals analyzed. The metallic components in the soil occur in the order Fe>Cr>Mn>Pb>Cd. The result shows that the concentration of Cr and Pb in the soil was above the World Bank Standard (WHO), while the concentration of heavy metals in drinking water was below the WHO standard. Iron has the highest concentration probably because of the ground geology and sedimentary formation of the parent soil. The most polluted site was Elekahiah, followed by Mile 3 and Ikokwu. Although there is a negative correlation between heavy metal concentration between soil and water (R2 = -0.22), there was a positive correlation of chemicals between surface and sub-surface soils (R2 = 0.99), which shows that migration of chemical components from surface to groundwater may be possible in future. The result implies that auto-mechanic junks can pose public health problems if the soil and groundwater are not constantly monitored.

Keywords: Automobile, Mechanic, Contamination, Vehicular Junks, Pollution, Groundwater.