EFFECT OF APPLICATION OF EDTA ON THE EFFICIENCY OF PHYTOEXTRACTION OF METALS FROM SOIL NEAR DUMPSITES BY SOME SELECTED PLANTS IN ZARIA NIGERIA

Abstract

 The aim of this study is to investigate the effect of the application of ethylenediamine-tetraacetic acid (EDTA) on the efficiency of phytoextraction of Cd, Co, Cu, Ni, Pb, and Zn by Vetiverazizanioide, Ipomoea asarifolia,Helianthus annus, Ricinuscommunis L. and Cymbopogoncitratusharvested from the soil treated with EDTA and that not treated with EDTA (natural). The concentrations of the metals in the plant species and soil were determinedusing atomic absorption spectrophotometry. The results showed that the metal concentrations in the soil (before planting) at the dumpsiteswere higher (P≤0.05) than the control and were above (except Cu and Zn) the standard limits as recommended by FAO/WHO). The concentrations of metals in all the plants harvested from soil the treated with EDTA were found to be higher (P < 0.05) than those from the soil without EDTAtreatment.The percentages removal of Cd ranged from 36.7 - 52.5 (natural) and 59.7 - 70.3 (with EDTA); Co:- 0.6 - 15.7 (natural) and 1.2 - 19.2 (with EDTA); Cu:- 24.5 - 44.3 (natural) and 32.1 - 70.5 (with EDTA); Ni:- 20.5 - 88.4 (natural) and 35.6 - 90.5 (with EDTA); Pb:- 13.0 - 21.3 (natural) and 27.9 - 42.1 (with EDTA) and Zn:- 17.1 - 28.0 (natural) and 19.9 - 36.0 (with EDTA).This demonstrated that EDTA is an efficient soil amendment additive in enhancing metals desorption from the soil by increasing their accumulation in plants, hence enhancing the efficiency of phytoextraction of the heavy metals from the soil by the plants forthe purpose of detoxification of dump sites.