EDTA-Enhanced Phytoextraction by Tagetes sp. and Effect on Bioconcentration and Translocation of Heavy Metals

Abstract

Phytoextraction is one of the processes of phytoremediation, in which heavy metals are extracted by plant roots and shoots. For enhanced phytoextraction efficiency use of some chelating agent such as ethylenediaminetetraacetic acid (EDTA) is an effective approach to remove heavy metals from contaminated soils. In the present study, the effect of EDTA on the uptake of Zn, Cd, Pb, and Cu by Tagetes sp. was examined. The application of EDTA had inhibitory effects on the growth of the plants, but effectively increased the mobility of Zn, Cd, Pb, and Cu in soils, and significantly enhanced the accumulation of these heavy metals in aerial parts of the plants. The portions of Zn extraction from soil were increased by 1.71, 1.86 and 1.9 times, Cd extraction from soil was increased by 2.33, 2.44 and 2.46 times, Pb extraction from soil was increased by 1.65, 1.93 and 2.01 times and Cu extraction from soil was increased by 1.93, 1.95 and 2 times, under the treatments of 5 (E5), 10 (E10) and 15 mg EDTA/kg of soil (E15), respectively, compared to the control. The highest bioconcentration factor of shoot (BCFshoot) and the translocation factor (TF) were observed in E15 and highest remediation factor (RF) was observed in E10. But 5 mmol EDTA/kg of soil is the best treatment for selected heavy metals remediation because it has less toxic effects on plant as well as it is economical both cost wise and for the decorative flowers.