Suitability of different mediterranean plants for phytoremediation of mine soils affected with cadmium

Abstract

Mine residues dumped on the environment as overburden or tailings ponds show environmental and human health hazards by the transfer of heavy metals through erosion or leaching. The objective of this study was to assess the potential use of different Mediterranean plant species for phytostabilization or phytoextraction of cadmium in acidic mine residues. For this purpose, a reclamation strategy was carried out in a mine tailing based on the use of phytoremediation aided with three different amendments (pig slurry, pig manure, and marble waste). -Six Mediterranean species were introduced: Lygeum spartum, Atriplex halimus, Helichrysum stoechas, Dittrichia viscosa, Piptatherum miliaceum, and Limonium cossonianum. Soil and plant samples were collected 24 months after remediation works. Results showed that the characteristics of the mine residue improved with the reclamation developed, with increased pH, organic matter and fertility, and decreased salinity. The extractable and exchangeable fractions of Cd decreased 85 % and 96 %, respectively. The tested species (except for A. halimus and L. cossonianum) may be potential candidates for the objectives of Cd phytostabilization since they showed low translocation and bioaccumulation factors. P. miliaceum was the best candidate owing to its lower translocation and bioaccumulation factors, higher biomass, and higher colonization of the area. A. halimus seems a potential candidate for phytoextraction rather than for phytostabilization of soil Cd, with high translocation and bioaccumulation factors, high biomass, and fast growth.