Heavy Metals in Tree Parts (Roots, Bark, Leaves) and Fruits Grown in Mechanic Workshops in Nigeria

The day-to-day activities carried out at the mechanic workshop like panel beating, welding, and automobile battery servicing may result in high amounts of heavy metals in the soil near mechanic workshops. Spent engine oils also emit a huge number of toxic metals, when disposed of on the floor at workshops, they settle on soil and are absorbed into nearby trees and plants. Therefore, making the tree parts and fruits at mechanic workshops prone to attack by heavy metals. This work is focused on testing if the presence of heavy metals would have adverse effects on the tree parts (roots, shoots, upper leaves, lower leaves) and fruits of mechanic workshops. A mechanic village in Abeokuta, Ogun State was chosen as the case study. The tree parts were oven-dried, ground, digested, and taken for analysis using AAS. Zinc (Zn), Lead (Pb), and Mercury (Hg) were found in higher amounts than the recommended allowable limits by WHO/FAO. Results show that the upper bark had the highest heavy metal concentration. In general, the tested heavy metals were recognized in the order: Zinc (Zn) > Lead (Pb) > Mercury (Hg) > Nickel (Ni) > Manganese (Mn) > Iron (Fe) > Copper (Cu). It is recommended that mechanic villages should be sited far from residential areas. Remediation of polluted soil should be encouraged. Phytoremediation was suggested to be the best method for reducing the concentration of heavy metal in the soils and tree parts at mechanic workshops. Continuous education and training should be provided for automobile repairers/ mechanics, emphasizing the environmental implications of their poor occupational waste management and the dangers of eating fruits and taking herbs from trees planted in workshops.