Mining contributes more to the gross domestic product of Chile than any other sector. Tailings, abandoned mines, closures and other areas affected by mining activities require stabilization and revegetation within an environmentally sound context. A study performed in the Coquimbo region, found that 420 species, or about 28 % of the Chilean native regional flora, were able to spontaneously colonize tailings. Furthermore, another study described that the Coquimbo flora represents 30 % of the Chilean flora with 54 % of endemism in Chile. Many of these plants have multiple uses and have a certain level of vulnerability related to their conservation status. In order to ensure a sustainable industry, it is necessary to clarify whether metals are mobilized to aerial tissues or not, to guide the optimization of their use either for stabilizing sites or extracting pollutants. We evaluated a polyculture of more than 25,000 individual plants, planted in 2012 in three treatments: tailings, tailings and mycorrhiza, and tailings and compost. The species were assessed for survival, growth, vigor, chlorophyll content index, chlorophyll fluorescence (as a stress indicator), root and shoot metal concentrations, etc. We found that all the species analysed had some level of stress. Most of the significant differences were driven by species rather than treatment. In terms of survival, Prosopis chilensis (algarrobo), Baccharis linearis (romero), Schinus polygamous (huingan) and Acacia caven (espino) lead the list. Copper was most concentrated in the roots, and readily mobilized towards the leaves in most cases, but translocation was lowest in algarrobo and Quillaja saponaria (quillay). For this reason, and because of lower uptake overall, quillay is recommended if the ambition is to stabilize sites while also reducing transport to aerial tissues.
Milla Moreno, E & Guy RD. 2018. Phytoremediation of tailings from a Chilean Copper Mine. GECAMIN (Conference proceeding).