Differential uptake of silver, copper and zinc suggests complementary species-specific phytoextraction potential

ABSTRACT

The aim of our study, conducted as a pot experiment, was to assess the potential of willow (Salix miyabeana), alfalfa (Medicago sativa), tall fescue (Festuca arundinacea), and Indian mustard (Brassica juncea) to remediate two brownfield soils differentially contaminated with Ag, Cu and Zn (up to 113.60, 47.50, and 117.00 mg kg⁻¹ respectively). While aboveground Ag accumulation was highest in B. juncea (4.60 ± 2.58 mg kg⁻¹), lower levels were also measured in M. sativa and F. arundinacea. Cu accumulation was observed in all species, but only in underground parts, and was highest in F. arundinacea (269.20 ± 74.75 mg kg⁻¹), with a bioconcentration factor of 13.85. Salix miyabeana was found to have the highest Zn aerial tissue concentration (119.96 ± 20.04 mg kg⁻¹). Because of its high Ag uptake, the remediation potential of B. juncea should be evaluated more extensively on the site from which we excavated the soil for this study. Given the multiple forms of contamination on the site and the differential specie-related uptake evident in our findings, we hypothesize that an optimal plantation allowing expression of complementary remediation functions would include B. juncea for extraction of Ag, in combination with F. arundinacea for stabilization of Cu and S. miyabeana for extraction of Zn.

Acknowledgments

This experiment was conducted with financial support from Mitacs. Dominic Desjardins is supported by a FRQNT BMP doctoral scholarship. The research team would like to thank all the individuals who assisted in sample collection, processing and data analysis, as well as Karen Grislis for English revision.