Removal of Prussian blue from contaminated soil in the rhizosphere of cyanogenic plants

Abstract

The fate of radiolabeled cyanide in soil was investigated during exposure to cyanogenic plant species, sorghum ( Sorghum bicolor var. P721) and flax ( Linum usitassimum var. Omega-Gold), in fully-contained growth chambers. Labeled cyanide was subject to microbial transformation, assimilation by plant roots, incorporation and biodegradation in plant tissue. For this study, 14C-labeled cyanide was added to soil, and distribution of 14C activity was assessed before plant establishment and after harvest. After 3 months of plant growth, 7% of the 14C-labeled cyanide was converted to 14CO 2 with sorghum and 6% with flax, compared with only 2% conversion in unplanted soil. A small amount of unaltered cyanide was shown to be accumulated by the plants (≈140 mg cyanide/kg plant or <0.1% of the total). Results from this experiment demonstrate the potential of cyanogenic plants for use in phytoremediation of cyanide-contaminated soil.