Speciation of heavy metals in soil, and their phytoavailability in edible part of Amaranthus hybridus cultivated along major roads in Ile- Ife, Nigeria

摘要

Heavy metal content in soil andAmaranthushybriduscultivated on it were determined by speciation method and acid dissolution. The atomic absorption spectrophotometer was used to quantify the metals in the soil and vegetable. Themobilisationof metals from soil to plants as indicated by the metal contents in the soil and vegetables decreased in this order Fe Mn Zn Cu Pb As ≥ Cd. The metals concentration ranges in the soil and vegetables as follows: {Fe (12.540-20.915), Mn (1.727-2.506), Zn (0.717- 1.571), Cu (0.292- 0.569), Pb (0.019-0.030) As (0.016-0.033) and Cd( 0.015- 0.028)}µg/g : {Fe (7.359-11.205), Mn (0.964-1.580), Zn (0.542- 1.220), Cu (0.010- 0.272), Pb (0.015-0.085) As (0.012-0.019) and Cd (0.012- 0.018)} µg/g respectively. The total metal concentration found in the vegetables was more than the metal uptake from the soil, indicating contamination of the vegetables from other sources. The heavy metals concentrations were within the safe limit of WHO/FAO. There was no statistical significant difference between the metal uptake by vegetable and total metal in the vegetable at 95 and 99% of probability level. At present the vegetables may not pose health risk but the plots needed to be monitored from time to time.