Phytoavailable content of metals in soils from copper mine tailings (Touro mine, Galicia, Spain)

• The amount extracted with CaCl2 best predicts the phytoavailability of metals.
• The translocation factor is > 1 for all plant species except for F. rubra.
• The bioconcentration factor is > 1 for all metals except for Cu in some cases.
• All selected plant species are accumulators of Mn and Ni but not of Cu and Zn.

This study was carried out on minesoils from a copper mine in Touro, NW Spain. The aims were to evaluate the effectiveness of a variety of extractants for predicting the availability of trace metals, to use the plants that colonize the affected area to evaluate metal absorption, and to assess the potential of colonist vegetation for the phytoremediation of mine tailings. Copper, Mn, Ni and Zn were found in all soils. Total soil Cu exceeds the intervention limits. In general, the extracted amount of the metals was in decreasing order: CaCl2 > EDTA > DTPA > AOBPM > BDW. The amount of metal extracted with CaCl2, followed by EDTA, best reflects the availability of these elements in these soils. In these soils, and for all of the metals studied, the translocation factor is > 1 except for Festuca rubra that accumulates higher amounts of the metals in the root than in the shoot. In general, the bioconcentration factor was > 1 except for Cu in some cases. All selected plant species are mainly accumulators of Mn and Ni and therefore special care must be taken with the Zn and especially with Cu contents in the soils from Touro mine.