Plants from mine spoils in the South American Area as potential sources of germplasm for phytorenmediation technologies

Abstract

The selection of adequate plant species is a prerequisite for cleaning-up contaminated soils by means of phytoextraction which is a time and cost-effective technology. Here first results of the screening of plant species from three different mining areas in South America are reported: A copper mine in Peru ("Mina Turmalina"), a silver mine in Ecuador ("Mina San Bartolomé") and a copper mine in Chile ("Mina El Teniente"). The accumulation of heavy metals and As in shoots as a function of extractable metal concentrations in the soils was analyzed in field samples. The different plant species collected on the severely polluted soils exhibited large differences in shoot accumulation of heavy metals and As. Among the grass species (Poaceae), the highest shoot As concentrations were found in Paspalum sp. (> 1.000 μg/g) and Eriochloa ramosa (460 μg/g) from the Cu mine in Peru, and in Holcus lanatus and Pennisetum clandestinum (> 200 μg/g) from the silver mine in Ecuador. Paspalum racemosum also accumulated considerable concentrations of Cu and Zn. The species from the genus Bidens (Asteraceae) were able not only to accumulate high shoot As concentrations (> 1000 μg/g in B. cynapiifolia from Peru), but also considerable amounts of Pb (B. humilis from Chile). The highest Cu shoot concentrations were found in Mullinum spinosum (870 μg/g) and in B. cynapiifolia (620 μg/g). The shoot accumulation of Zn was highest in Baccharis amdatensis (> 1900 μg/g) and in Rumex crispus (1300 μg/g) from the silver mine in Ecuador. The potential usefulness of these species for phytoremediation technologies is discussed.