Potential of energy crops for the phytoremediation of a soil polluted by serpentine mining

Abstract

Phytoremediation using energy crops offers both environmental and energy-related benefits; however, its effectiveness in soils contaminated with nickel (Ni) and chromium (Cr) due to serpentinite mining requires further investigation. This study aimed to assess the potential of energy crops for the phytoremediation of soil contaminated by serpentinite mining activities. The experiment was conducted using soil from a former chromite mining area in serpentinites, which was operational between 1945 and 2010, in the municipality of Cromínia, State of Goiás, Brazil. A randomized block design was adopted, comprising five treatments with four replicates: energy cane, sugarcane, capiaçu grass, elephant grass, and spontaneous flora. The total concentrations of Ni and Cr in the soil were quantified. In plants, shoot and root biomass production, Ni and Cr accumulation, and energy productivity were evaluated. The translocation factor and bioconcentration factor for the metals were determined. Data were subjected to analysis of variance and the Scott-Knott test. Sugarcane exhibited the highest biomass production and energy productivity. Reductions in total Ni and Cr concentrations in the soil were observed at 58% and 22%, respectively, which may be associated with metal retention in the roots through phytostabilization. By ensuring high biomass yields, enabling renewable energy production, preventing metal transfer to other environments and organisms, and providing socioeconomic benefits, the cultivation of energy crops presents a sustainable alternative for the phytoremediation of decommissioned serpentinite mining areas.