Phytoextraction of Heavy Metals by Vetivera zizanioides, Cymbopogon citrates and Helianthus annuls

摘要

The research work under field conditions is to investigate the connection between the heavy metals concentration in soil and their bioaccumulation in Vetivera zizanioides, Cymbopogon citrates (Lemon grass) and Helianthus annuls (sunflower) collected from experimental site and a control area in Zaria-Nigeria. The collection was done by dividing the experimental and control sites each into four quadrants, five plants samples of each species and soil samples were collected from each quadrant in a diagonal basis. The concentrations of Cd, Co, Cu, Ni, Pb and Zn in different parts of each of the plant species collected from the experimental and control soils were determined using atomic absorption spectrophotometry. The experimental levels of the metals were higher (P ≤ 0.05) than those at the control site and the limits recommended by Food and Agricultural Organisation/World Health Organisation (FAO/WHO). The heavy metal concentrations were higher in leaves (P ≤ 0.05) than in roots of the plants tested. Vetivera zizanioides showed the bioaccumulation factor (BF) and translocation factor (TF) values for the studied metals greater than 1 (except Co and Pb that had their BF less than 1). Cymbopogon citratus showed BF values of Cd, Ni and Pb were greater than 1, but TF of all the metals studied were greater than 1. Helianthus annus plant had BF values for Cd, Cu and Zn greater than 1, but TF values for all the metals studied were greater than 1. This indicated that Vetivera zizanioides, Cymbopogon citrates and Helianthus annuls have good phytoextraction potentials for the removal of heavy metals from contaminated soils.