The Effect of Nitrilo Triacetic Acid (NTA) on Cd Phytoremediation by Maize in Soil Leaching Condition

Phytoremediation is a method to refine heavy metals from soil. Using chelators can increase the efficiency of phytoremediation. The aim of this study was to investigate the effect of Nitrilo Triacetic Acid (NTA) on growth indexes and the efficiency of phytoremediation by maize in Cd-contaminated soils under leaching condition. In this way, in the greenhouse, an experiment was conducted consisting three levels of Cd contamination (0, 25 and 50 mgkg-1 soil) and three levels of NTA (0, 15 and 30 mmolL-1 in pot). According to the results, the most amount of Cd in the shoot and root of the plant was observed in Cd50NTA30 (50 mgCd/kg soil and 30 mmolNTA/L in pot) by 2 and 1.8 times, respectively, than Cd50NTA0 (non-application of NTA). Also, the amount of Cd in drainage water in both of Cd25 and Cd50 with apply NTA30 were the maximum amount. In Cd50NTA30 toxicity symptoms were observed in the form of yellowish leaves, decreased chlorophyll index, necrosis and a significant decrease in dry weight of plant organs, leaf area, and plant height. In Cd50NTA30 the amounts of BAC and BCF were increased by 2.8 and 2.4 times, respectively, than Cd50NTA0. In the case of similar treatments, the amount of TI was decreased by 33%. TF could only show a significant increase in Cd50NTA30 than Cd50NTA0. According to the results, the use of NTA as a chelator that has the least environmental damage can significantly increase the efficiency of phytoremediation by maize.