Abstract:
Auto mechanics have over the years played a major role in the
transport industry in Ghana by providing services to many road users
including; heavy duty cars, tankers, salon cars, commercial vehicle among
others. In the process of discharging their duties, they intentionally and
unintentionally deposit various waste from vehicles on the soil within the
workshops and the adjoining fields. A survey was conducted to assess the
impact of automobile waste on soil heavy metal levels and soil microbial
activity. Two auto mechanic workshops at Edwenase and South Suntreso in
Kumasi Metropolis (Ashanti Region of Ghana) were considered. The
experimental design used was Randomized Complete Block Design.
Composite soil samples were taken at depths of 0-10 cm and 10-30 cm from
the upper part through to the middle part and to the valley bottom and analyse
for heavy metals including; Pb, As, Zn and Cd. Selected parts of maize and
plantain at the adjoining fields were also randomly sampled for heavy metal
accumulation analysis. Soil samples were subjected to microbial activity
analysis using the basal respiration method. The levels of Zinc recorded in the
soil sample were highly above the FAO acceptable limit of 3.5 – 6 mg/kg. The
levels of arsenic at South Suntreso were within the FAO acceptable limit of 20
mg kg-1. Pb of plant samples had 0.03 mg/kg level. Zinc levels emerged the
highest at 15.47 mg/kg in plant biomass. At South Suntreso, the valley bottom
recorded the highest microbial activity of 65.24 mgCO2/kg soil/day. After the
study, it was established that there were some traces of heavy metals in soil
and plant samples at the two study sites; and the presence of the heavy metals
had an effect on soil microbial activities.
