A Study of Bacteriological and Physicochemical Characteristics in Soils of Auto-mechanic and none Auto-mechanic Workshop Soils from Selected Areas in Calabar Metropolis

The research study was aimed at investigating physicochemical and bacteriological characteristics of auto-mechanic and none auto-mechanic workshop soil samples. Auto-mechanic and non auto-mechanic workshop environments were randomly sampled within Calabar Metropolis. The study was completed within a period of six months. Standard microbiological methods were used to isolate, characterize and identify bacteria from the collected soil samples. The mean heterotrophic bacteria counts were higher in the auto-mechanic workshop soils compared to their non auto-mechanic workshop soil counterpart. Bacteria isolates from the auto-mechanic mechanic workshop soil samples were identified as species of Aeromonas, Serratia, Klebsiella, Corynebacterium, Yersinia, Shigella, Enterobacter and Escherichia coli, while those isolated from the none auto-mechanic workshop soils were identified as Citrobacter, Yersinia, Bacillus and Serratia. Comparison of the mean physicochemical parameters of the auto-mechanic workshop and non auto-mechanic soil samples showed significantly lower values of pH and available phosphorus in the auto-mechanic workshop soils whereas C:N ratio, calcium, total hydrocarbon concentration effective carbon exchange capacity and base saturation percentage values were significantly (P<0.05) higher in the auto-mechanic workshop soil samples. The concentration of heavy metals varied widely among the location studied. The mean Zn, Cu, Fe, V, Ni, Cd, Pb, Co, Cr were higher in the auto-mechanic workshop soil samples than in the none auto-mechanic soil samples. However, the total hydrocarbon values for the studied auto-mechanic soil samples showed that the mean values of 5266.7 mg/kg, 4413.2 mg/kg, 3130 mg/kg and 4514.4 mg/kg (AMT, AMM AME, and AMI) were above the recognized biogenic value of 50 mg/kg reported by DPR (1991), as these is environmentally significant and indicative of gross contamination which could in turn stimulate a wide variety of environmental issues.