Physicochemical and Microbial Properties of the Soil Samples Collected from Auto-Mechanic Workshop, Orubor-Agbor, Delta State, Nigeria

Abstract

Auto-mechanic workshops are major concerns due to the repeated discharge of spent engine oil to the receiving soil. This study investigated the qualities of soil samples from an auto-mechanic workshop located in Orubor, Abgor, Delta State, Nigeria. The collected soil (n=36) was characterized for physicochemical and bacteriological quality using standard procedures. The physicochemical results wet season were pH (5.25 ± 0.07 to 6.15 ± 0.07), electrical conductivity (45.0 ± 7.07 to 165 ± 7.07 µS/cm), organic carbon (1.53 ± 0.42 to 10.1 ± 0.16 %), nitrogen (0.05 ± 0.00 to 0.44 ± 0.01 %), phosphorus (0.69 ± 0.05 to 5.20 ±0.02 mg/kg) and total hydrocarbon content (151 ± 1.41 to 572 ± 3.53 mg/kg). The dry season recorded pH (4.78 ± 0.04 to 5.73 ± 0.04), electrical conductivity (44.1 ± 6.29 to 1.62 ± 4.60 µS/cm), organic carbon (1.21 ± 0.07 to 7.52 ± 0.13 %), nitrogen (0.47 ± 0.00 to 0.58 ± 0.00 %), phosphorus (0.90 ± 0.57 to 6.79 ± 0.09 mg/kg) and total hydrocarbon content (98.9 ± 0.44 to 373 ± 6.36 mg/kg). There was no significant difference (p˃0.05) in the physicochemical parameters concerning the sampling periods. The total heterotrophic bacterial and total naphthalene utilizing bacterial counts were 9.67 ± 1.04 × 105 cfu/g and 5.40 ± 0.88 × 105 cfu/g respectively. The major bacterial isolates were Serratia, Pseudomonas, Enterococcus, and Providencia spp. Findings from this study revealed the necessity for public education and stricter waste management practices within auto-mechanic workshops to stem the negative effects of spent auto-engine oil pollution in the