Effect of Sunflower and Amaranthus Culture and Application of Inoculants on Phytoremediation of the Soils Contaminated with Cadmium

Abstract: Cadmium is a toxic element in plant and human nutrition which is added to the soil from different sources especially consumption of phosphate fertilizers with high cadmium concentration, application of industrial wastewaters, mine extraction operations and metal melting and leads to contamination of environment. Phytoremediation is an effective, economical and biocompatible method for remediation of contaminated soils. This research was executed in order to study effect of sunflower and amaranthus culture and inoculants of two native bacteria resistant to cadmium on phytoremediation of this metal. In a calcareous soil of Karaj region (Fine Loamy, Mixed Super Active Thermic Xeric Haplocambids) and in green house conditions, effect of culture of the two plants, sunflower and amaranthus and three levels of control inoculants (BO), Bacillus mycoides M1 (B1), Micrococcus roseus M2 (B2) and four levels of control cadmium concentration (0, 50, 100 and 200 mg/kg) was studied in a factorial experimental design with random blocks basic design with three replications. Concentration of cadmium, iron and zinc were measured in shoot and root as a function of dry material and photosynthetic chemical efficiency. The analysis of variance analysis showed that application of inoculant significantly (P< 0.01) increased phytoremediation efficiency and effect of amaranthus in cadmium phytoextraction was higher than that of sunflower. It seems that effect of sunflower on phytoremediation is generally through phytoestabilisation and effect of amaranthus is through phytoextraction process. Treatments