Phytoremediation potential of plants growing spontaneously on abandoned coal mine wastes

Abstract

Abstract Coal mining activities cause drastic perturbation of vegetation, soil and diffuse heavy metal to environment. Hence, identification of heavy metals tolerant species is essential for ecological restoration of mine impacted lands. This study aimed to assess the concentration of heavy metals in soils and the phytoremediation potential of 13 dominant plants naturally growing on abandoned coal waste dumps in northern Iran. Plant roots and shoots and the corresponding soils were sampled and then prepared, dried and milled in the laboratory. The results showed that metals concentration varied among plants and for each species between root and shoot. Majority of plants accumulated greater metals in aboveground biomass than belowground biomass, which indicates their effective metal translocating capacity. Artemisia scoparia and Capparis spinosa were contained the highest concentrations of Cu in shoot with 41.06 and 42.48 mg/kg, and TF>1 indicating the capacity for phytoextraction. The accumulation of Arsenic in the shoots and roots of Sylibum marianum was higher than normal. Cynodon dactylon and Hordeum vulgare were the only plants that accumulated >100 mg/kg Zn in the roots and can be recommended for phytostabilization. S. marianum and Chenopodium album potentially can be considered as Cd-accumulator. Kochia prostrate with BCF and TF < 1 for most detected metals is the only excluder species. The only indicator species for Vanadium was S. marianum with a transfer factor of 2.01. S. marianum and Glaucium fimbriligerum showed a tolerance mechanism to Strontium. The findings confirmed the potential of these plants in translocating of metal(loid)s from roots to the aerial parts.