Abstract
The concentrations of heavy metals were determined from the soil of the mechanic village, in Abeokuta and a control farmland located at Federal University of Agriculture, Abeokuta (FUNAAB). The soil sample collected at the base of different species of tree showed that the heavy metals were below permissible levels (FAO/WHO and EC/CODEX standard) and show no significant difference in the range of mean. Absorption of heavy metals by the bark of the trees in the mechanic village was evident when compared relatively to the presence and uptake of the heavy metals from the soil by tree in the farmland. The mean concentrations of the heavy metals in the soil of the farmland are in this order of magnitude Cd>Cu>Pb, while the mean concentration of the heavy metals in the soil of the mechanic village are in the order of magnitude Pb>Cu>Cd. Lead has the least concentration in the farmland, while in the mechanic village, it is the predominant heavy metal detected which also shows greater significant different at p<0.05 with a value of 24.34 mg/kg indicating area of high mechanic activities. The concentration values of heavy metals in the barks in comparison to the standard shows that the concentration of the heavy metals in those vicinities is within the permissible range for cadmium and copper, while lead present was above the WHO/FAO standard at 0.299 mg/kg and close to the EC/CODEX standard. It can also be concluded that the uptake efficiency of heavy metal under study of the three species are in the order magnitude Mango>Cashew>Neem.
Key words: Absorption, concentration, farmland, magnitude, phytoremediation.
