Wild plants canopies may adsorb dust particles eroded from mine tailings, decreasing potentially toxic elements dispersion

Mine tailings are a source of contamination to soil, air, and water. Plant leaf surfaces may retain potentially toxic elements and deplete their dispersion. This study aimed to evaluate the potential of wild plant species as phytobarriers of areas affected by the dispersion of mine residues. Soil and plant samples were collected from 51 sites. The pseudo-total and DTPA-extractable Cd, Pb, Cu, Zn, and Mn concentrations were measured in soil. Washed and unwashed plant samples were analyzed to calculate the phytobarrier index. High pseudo-total and extractable concentrations of Pb, Zn, and Cd were found in the whole area, and strong influence by mine residues was observed. Twenty-two plant species were able to adsorb dust on leaves. P. lanceolata, Cucurbita spp., Medicago sativa had 5.5, 3.5, and 3.2 times more Pb on the surface than inside the plant. The plants capture particles in different degree. The highest phytobarriers index and widespread sites distribution were observed in Sanvitalia procumbens (37-48), Dichondra argentea (40-62), Dyssodia pinnata (34-62), Aster gymnocephalus (32-51), Flaveria trinervia (39-47), Jatropha dioica (32-48), and Brickellia veronicifolia (32-70). The plant species have different abilities to catch particles according to the specific site conditions where they were growing. Probably, native plant species may serve for air phytoremediation near the mine tailings at arid and semiarid areas.