Phytoremediation Potential of Canna indica (Indian shot) for Cobalt and Zinc Contaminated Soil

Abstract

Rapid industrialization and urban expansion lead to the accumulation of toxic heavy metals in the soil and water system, such as Zinc (Zn) and Cobalt (Co). Traditional methods used for remediation of heavy metals from soil are expensive, unsustainable and generate a lot of secondary waste, which is difficult to manage. Phytoremediation, on the other hand, acts as an effective alternative to conventional methods, which use plants to extract and stabilize contaminants with a sustainable and cost-effective approach. This study examines the phytoremediation potential of Canna indica in removing heavy metal contaminants, i.e. zinc and cobalt, from the soil. A 45-day pot experiment has been conducted with three replicates per treatment, at concentrations of 2 mg/L and 5 mg/L for both metals under natural light conditions. Further, the accumulated concentration of both metals was measured using Atomic Absorption Spectroscopy (AAS). The data revealed discernible trends in the accumulation of both metals. Zinc is primarily accumulated in rhizomes, showing translocation rates of 80.82% at 2 mg/L and 41.79% at 5 mg/L, implying a phytostablization mechanism. On the contrary, Canna indica translocated Cobalt mainly to the aerial parts, with the very high translocation values of 305.61% at 2 mg/L and 160.78% at 5 mg/L, suggesting effective phytoextraction. Decreasing values of translocation as the concentration of contaminants rises may be due to phytotoxic stress. Thus, the findings support the dual efficiency of Canna indica both as a phytoextractor and phytostablizer for Cobalt and Zinc, respectively.