Perspectives for phytoremediation capability of native plants growing on Angouran Pb–Zn mining complex in northwest of Iran

Phytoremediation is a cost-effective, environmentally-friendly and emerging remediation technology that treats polluted areas using plants, having the potential to restore ecosystems and make compromised areas useable again, therefore returning a resource to community use. In the present work a study was conducted on the contamination of soil by heavy metals (Zn, Pb, Cr, Cd, and Co) in the mining area of Angouran (northwestern Iran) and on their uptake by 25 native species present in the mining district, in order to evaluate their potential use in phytoremediation interventions. Plant and soils from three sites around the mine were sampled and characterized, and metals accumulation and translocation were evaluated. Principal Component Analysis (PCA) and Cluster Analysis (CA) were applied to study the behavior of species in the accumulation and translocation of the elements in their tissues. The contents of Zn, Pb, Cr, Cd, and Co in the studied plants were, respectively, 31.77–723.05, 7.78–233.25, 1.77–21.57, 0.04–7.92, and 0.15–9.97 mg/kg. Among the 25 species, 13 plants showed translocation factor greater than one (TF > 1) for Zn, 14 for Pb, 3 for Cr, 10 for Co, and 6 for Cd. Marrubium cuneatum having an accumulation factor greater than one (AF > 1) for Zn and bioconcentration factor greater than one (BCF >1) for Cd can be considered as an accumulator and stabilizer for Zn and Cd, respectively. Also, the highest value of Pb (233.25 mg/kg) and Cr (21.57 mg/kg) were found in the shoot of this plant. Psathyrostachys fragilis with BCF >1 for Co and maximum Pb accumulation in the root can be used as a stabilizer plant for Pb and Co-contaminated soils. Besides, Stipa arabica and Verbascum speciosum, with TF > 1 and rather high AF, could be considered suitable species for removing Zn and Pb through phytoextraction. This research showed that some native species in the study area have considerable potential for developing phytoremediation strategies.