ABSTRACT
The extent of Groundwater and soil contamination arising from Auto-mechanic workshop at Uwelu and G.R.A were examined. Soil and water contaminated with heavy metals can result to very serious environmental hazard. As a result of this arising problem, this research was carried out to assess the concentration of heavy metals in and around “Uwelu” and “Country Home Road (G.R.A.)” in Benin City, southern Nigeria.
In carrying out this research, a total of 6 Groundwater samples were collected and a total of twenty-four (24) soil samples were collected including control samples at depth 0-15 and 15-30 cm were analysed using Atomic Absorption Spectrophotometer (AAS) PG 550 model with Air acetylene flame, Silver Nitrate titration, Spectronic 2D Spectrophotometer and Gravimeter. The soil result revealed at Uwelu, that the pH ranges from 5.2 – 7.6, EC 97.5 – 345.1 (mg/kg), Fe 135.3 – 564.7(mg/kg), Mn 14.1 – 76.0(mg/kg), Zn 63.8 -603.1 (mg/kg), Cu 4.0-9.7 (mg/kg), Cr 0.25-0.84 (mg/kg), Cd 0.21-0.60 (mg/kg), Pb 0.65-1.91(mg/kg), Ni 0.58-1.54 (mg/kg), V 0.37-0.92 (mg/kg) and results for groundwater at Uwelu, pH ranged from 4.0 -4.1, E.C 46.5 – 60.7(mS/cm), Mn 0.030-0.044 (mg/l), Zn 0.005 -0.016 (mg/l). The soil result revealed in GRA that the pH ranges from 4.6 – 6.9, EC 49.2 – 229.3 (mS/cm), Fe 135.3 – 564.7 (mg/kg), Mn 10.9 -32.9(mg/kg), Zn 12.8-99.8(mg/kg), Cu 3.1-8.1(mg/kg), Cr 0.1-0.53(mg/kg), Cd 0.10-0.50(mg/kg), Pb 0.23-1.63(mg/kg), Ni 0.21-1.07(mg/kg), V 0.14 -0.71(mg/kg) and results for ground water pH ranged from 4.0-4.1, E.C 45.5 -52.8(mS/cm), Fe 0.385-0.657(mg/l), Mn 0.041-0.47(mg/l), Zn 0.87-0.154(mg/l). The analysed groundwater were observed to have some concentration above the World Health Organisation (WHO, 2011) and Nigeria Standard for Drinking Water Quality (NSDWQ). This show the daily activities of automobile mechanic workshop have in part negatively impacted on both groundwater and soil.
