Lead Phytoextraction from Soil by Corn, Sunflower, and Cotton Species Applying EDTA and Sulfuric Acid.
Ebrahim Fattahi Kiasari, Amir Fotovat, Alireza Astaraei, and Gholamhossein Haghnia. Ferdowsi Univ of Mashhad, Mashhad 91775-1163, Iran
The contamination of soils with lead is a major environmental problem throughout the world. Phytoextraction of heavy metals from contaminated soils has the prospect of being a more economic in situ alternative. Chemically enhanced phytoextraction has been proposed as an effective approach to remove heavy metals from contaminated soil through the use of high biomass plants. Using a pot experiment, the effects of the application of three rates of EDTA at 0, 1.5 and 3 mmol.kg-1 and sulfuric acid at 0, 0.5 and 1 mmol.kg-1 with two rates of Pb at 0 and 200 mmol.kg-1 on the uptake of Pb by corn (Zea mays L.), sunflower (Helianthus annuus L.), and cotton (Gossypium hirsutum L.) plants were studied. The results showed that EDTA was more effective than sulfuric acid in increasing the concentration of Pb in shoots and roots for all plants studied. The maximum amount with application of EDTA to soil for shoots of corn, sunflower, and cotton were 4.07, 6.49 and 31.33 times higher than control, respectively. EDTA also enhanced Pb content of roots of corn, sunflower, and cotton 3.38, 1.63 and 1.09 higher than control, respectively. DTPA-Pb was higher in soil treated with EDTA than sulfuric acid. The application of EDTA also significantly increased shoot-to-root ratios of Pb in plants examined. The results of this study showed that corn was able to phytoextraction more Pb than sunflower and cotton. Keywords: Phytoextraction; EDTA, Sulfuric acid, Corn, Sunflower, Cotton, Lead