Miscanthus x Giganteus Composition in Metals and Potassium After Culture on Polluted Soil and Its Use as Biofuel

Abstract

A comprehensive study of Miscanthus x giganteus culture on brownfield has been carried out. Plants are an alternative being considered for the production of biofuel, but development of energy crops increased competition in the use of land resources. Brownfields cover approximately 239 Mha of the world’s unexploited soils. Miscanthus x giganteus is able to produce biofuel and is able to grow on polluted sites. The present study is focused on Cd, Cu, Cr, Ni, Pb, Zn and K contents in roots, rhizomes, stems and leaves to optimize bioenergy production on brownfields. Regarding metal partitioning, Cr and Ni are not accumulated in the whole plant. Bioconcentration factors and translocation factor calculations show that Cd, Cu, Pb and Zn are mostly stocked in rhizomes and roots. Low concentrations of metals in aboveground biomass should facilitate its use in combustion units. K content is similar in control samples and brownfield samples during the growing season but K remobilization is blocked at the end of autumn if plants are cultivated on brownfields. K increase in aboveground biomass could be a limiting parameter of biofuel production in brownfield cultures because of critical problems of fouling and slagging in combustion units. K regulation associated to exclusion of metal by Miscanthus x giganteus should be investigated to standardize engineering practices and more particularly in case of brownfield culture.