Use of Native Species and Biodegradable Chelating Agents in the Phytoremediation of Abandoned Mining Areas

The application of assisted phytoextraction to the remediation of abandoned mining areas can be a valuable method to reclaim these areas without modifying soil and landscape characteristics. An in situ application of continuous phytoextraction technique was carried out in the area of Campo Pisano, near Iglesias (Sardinia, Italy) followed by a laboratory assisted phytoextraction test using the biodegradable chelating agents MGDA and IDS. The plants used were Scrophularia canina L. subsp. bicolor, Cistus salviifolius L. and Teucrium flavum L. subsp. glaucum. The plant that demonstrated the better ability to accumulate heavy metals was C. salviifolius while S. canina demonstrated the better tolerance to metals. The low soil cation exchange capacity determined a high accumulation of metals immediately after chelant treatment up to 300 mg/kg of Pb and 3,000 mg/kg of Zn which did not further increase during the assisted phytoextraction experiment.