Phytoremediation: elimination of hexavalent chromium heavy metal using corn (Zea mays L.)

There are more natural and more cost-effective alternatives to economically over costing physical and chemical remediation of polluted agricultural soils. Heavy metals that exert a significant toxicity on the organisms in the environment are one of the primary dangerous materials. In the elimination of heavy metal toxicity in the soils, phytoremediation method is used as a new technology. In this study, the usability of corn ( Zea mays L.) in the phytoremediation of hexavalent chromium-contaminated soil. Moreover, the hyperaccumulator ability of the corn for Cr +6 heavy metal was evaluated. In order to increase the solubility of chromium heavy metal in the soil different amounts of chelator (EDTA) were applied to the soils. The study was conducted according to the random blocks experimental design under controlled conditions with totally 18 pots of 3 replicates of control and 5 different chelate doses (0, 10, 20, 40, 80 mmol/kg). The soils in the pots were incubated with 30 mg/kg Cr +6 as Chromium (VI) oxide (Sigma-Aldrich No: 232653) for 30 days. During the sowing of the corn seeds 150 mg/kg N, 100 mg/kgP 2 O 5 , and 125 mg/kg K 2 O were applied to the pots and watering was done when needed. After the harvest, the chromium contents of the root and stem were determined. The chromium in the stem of the control was 2.81 mg/kg, and it was 31.46 mg/kg in the stem of 80 mmol/kg EDTA application trial. This result was statistically significant at 5%. The chromium content of the root was 18.57 mmol/kg in the control condition while it was 34.95 mmol/kg in the root of the highest concentration of applied chelate. This study revealed that corn is a hyperaccumulator plant to be used in phytoremediation of the soils contaminated by Cr +6 .