Initial studies for the phytostabilization of a mine tailing from the Cartagena-La Union Mining District (SE Spain).

Mine tailings are one of the main environmental problems in post-mining landscapes and their removal is often complicated due to their high heavy metal content and dimensions. In this sense, using plant species for in situ stabilization may be an interesting and low cost option. Moreover, there are some plant species that have adapted to these conditions and are usually present at these contaminated sites. In this study, a mine tailing located in South-East Spain was investigated in order to establish lines for further phytostabilization research. A plot sampling design was carried out in order to characterize the soil properties. In addition, two plant species that have naturally colonized some parts of the tailing, Hyparrhenia hirta and Zygophyllum fabago, were sampled, including the analyses of their respective rhizospheric soils. The results of plot soil samples showed pH values from ultra acid to slightly alkaline. The electrical conductivity values were around 4dSm(-1) in plots with vegetation and 8dS m(-1) in the plot without vegetation. Total metal concentrations were high (4000 mg kg(-1) for Pb, 9000-15000 mg kg(-1) for Zn). DTPA- and water-extractable Zn were 5% and 3% of the total, respectively. H. hirta accumulated around 150 mg kg(-1) Pb in both shoots and roots. Zn concentration was 750 mg kg(-1) in Z. fabago shoots. DTPA-extractable Zn and Cu were positively correlated to plant uptake.