Pioneer Mediterranean Shrub Species Revegetating Soils Developed on Mining Soils/Spoils

Spontaneous and autochthonous species of plants growing on degraded and contaminated soils/spoils that survive in such environments show, in general, no symptoms of toxicity. This study compares concentrations of chemical elements in different leaves maturation and in different seasons of several native species in a massive sulphide in an abandoned mine area. The objective is to evaluate if these species can play an important role on the stabilization of degraded soils and mine spoils. Total concentrations of chemical elements were great in soils. However, in general, only <1% of the total concentration was extracted by DTPA or ammonium acetate solutions. Total and available fraction of the chemical elements has similar behaviour between soil sites. Mature leaves have higher concentrations of As, Cu, Fe, Mn, Pb and Zn than younger ones. An opposite behaviour occurs with S. Winter and spring variations in most chemical elements concentrations in the plant leaves are not significantly different, except for As. Elemental concentrations of plant leaves are independent of the same elements concentrations (total and available fraction) in soils where plants have grown. The concentrations of As, Cu and Pb in plant leaves were below the level of risk to be ingested by grazing animals, although soils are above the reported thresholds. Therefore, all studied plant species can be considered for phytostabilization programmes, but the use of the land for pasture may not be a solution considering that animals ingest soil along with herbage.