PHYTOREMEDIATION OF CADMIUM-CONTAMINATED SOIL BY BRASSICA SPECIES

Abstract

Phytoremediation is a green technology for the sustainable remediation of surface soils contaminated with toxic heavy metals. When added to soils the chelating agent ethylenediamine tetraacetic acid (EDTA) increased the solubility of heavy elements for plant uptake during phytoremediation. A greenhouse experiment was carried out with two Brassica species (Brassica juncea and Brassica carinata) grown on artificially contaminated soil (20 and 40 mg Cd kg-1) with EDTA added at a rate of 1 g kg-1 soil. With increasing Cd (0, 20 and 40 mg Cd kg-1 soil) contamination the biomass of both the Brassica species decreased. However, Brassica juncea was more tolerant of high levels of Cd in the soil in comparison to B. carinata. The results indicated that EDTA made the cadmium more available to the plants and lowered the Cd content of the soil. The magnitude of the increase in tissue (stem, leaf and root) Cd concentration was higher in B.juncea than in B. carinata and after the application of chelating agent (EDTA). The Brassica juncea species of Indian mustard has better potential for the phytoremediation of soil heavily contaminated with Cd (40 mg Cd kg-1 soil).