Assessment of Heavy Metal Contamination of Soil in Mechanic Workshops at Nekede and Orji, Owerri Zone, Imo State, Nigeria

Assessment of heavy metal contamination of soils in mechanic workshop at Nekede and Orji, Imo State was carried out using triplicate soil samples at depths of 0 – 15 cm from three sampling points and a control sample - sample point 1 (SP) 20m away from (SP2) and 40m from (SP 3), control point, 1km away from each of the automobile workshops. A total of twelve (12) solil samples were collected using a soil auger. The soil samples were analysed for the following heavy metals (Lead, Copper, Zinc and Nickel) using AA Atomic Absorption Spectrophotometer. Data generated were subjected to statistical analysis such as means and Standard deviation using least significant difference (LSD). Results showed lower concentrations of the heavy metals in soil from control point as compared to soil samples collected from mechanic workshops. Across the sampling point, Zn, Pb, Cu and Ni had concentrations 1.75-89 mg/kg, 1.15-51.15 mg/kg, 0.55-29.35 mg/kg and 0.3-4 mg/kg respectively. Mean concentrations of Zn (49.27 mg/kg), Pb (23.70 mg/kg), Cu (18.25 mg/kg) and Ni (3.58 mg/kg) were higher in the soil samples from auto workshops of Orji compared to Nekede. Across the different sampling points, both Zn (89 mg/kg) and Pb (15.36 mg/kg) were higher in Nekede SP 1 whereas Cu (29.35 mg/kg) and Ni (4 mg/kg) were higher in Orji SP 1 and SP 2 respectively. Assessment of the extent of lead contamination / pollution showed that Zn contamination ranged from very slight Pb varied from very slight, moderate, Cu ranged from low- very low concentration, while Ni varied from very slight’ slight. The study therefore, recommends the control and supervision in the use of land allocated as mechanic workshop to reduce the accumulation of heavy metals.