Effect of EDTA on Uptake of Lead and Cadmium by Canola

Lead (Pb) and cadmium (Cd) are among heavy metals which enter water, soil, plants and ultimately the human and animals food chain from variouse resources and can cause serious damages. Several methods has been suggested for remediation of contaminated soils. Phytoremediation is a promising technology for this purpose. Harvesting and maximum extraction of contaminants from soil environment is the purpose of phytoremediation. Use of chelates, is one of the effective approaches for increasing the bioavailability of heavy metals. Therefore, In this study, the effects of Ethylene Diamine Tetra-acetic Acid (EDTA) as a chelating agent on increased absorption of Pb and Cd by Canola (Okapi) were studied. A pot experiment was conducted in the greenhouse as a factorial and completely randomized design with three replication. Factors included of : 1- EDTA Application in two levels (0 and 2.7 mmolkg-1 soil), 2- Pb at three levels ( 0, 150 and 500 mgkg-1 soil) and 3- Cd in three levels (0, 3 and 10 mgkg-1 soil). Consequently, a non- contaminated soil was selected and contaminated with different amounts of Pb and Cd. Then, canola seeds were planted and after harvest, Pb and Cd concentration in plants (grain and straw) and soil was measured. The results showed that EDTA Application was able to increase Pb and Cd solubility in soil solution, resulting in increased absorption of Pb in straw (25.6 times) and grain (11.2 times) and Cd in straw (12 %). Also studying the Pb and Cd concentration in canola showed that in canola straw in contaminated treatments, Cd concentration (7.35-23.1 mgkg-1) in both levels of EDTA and Pb concentration (106.47-275.48 mgkg-1) only in treatment with EDTA were observed in toxicity limit.