Potential for Phytomining of Rare Earth Elements by Naturally Occurring Plants in Reclaimed Tailing Ponds

Rare earth elements (REEs) from the ex-mining area (reclaimed tailing ponds) in East Rodope, Bulgaria, were investigated in soil and different plant species using inductively coupled plasma-optical emission spectrometry (ICP-OES). The tailings pond was reclaimed 20 years ago. The research work aims to determine the potential for phytomining of rare earth elements by naturally occurring plants in reclaimed tailing ponds. In the soil samples, the concentrations of cerium (Ce), lanthanum (La), and gadolinium (Gd) exceeded the average content of the elements in soils. The bioconcentration factor (BCF) was calculated. It was found that light rare earth elements (LREEs) are in greater concentration in plant samples than heavy rare earth elements (HREEs).