Phytoremediation Potential of Native Plant Species in Mine Soils Polluted by Metal(loid)s and Rare Earth Elements

Abstract

Mining activity has an adverse impact on the surrounding ecosystem, especially via the release of potentially toxic elements (PTEs); therefore, there is an urgent need to develop efficient technologies to remediate these ecosystems, especially soils. Phytoremediation can be potentially used to remediate contaminated areas by potentially toxic elements. However, in soils affected by polymetallic contamination, including metals, metalloids, and rare earth elements (REEs), it is necessary to evaluate the behavior of these toxic elements in the soil-plant system, which will allow the selection of the most appropriate native plants with phytoremediation potential to be used in phytoremediation programs. This study was conducted to evaluate the level of contamination of 29 metal(loid)s and REEs in two natural soils and four native plant species (Salsola oppositifolia, Stipa tenacissima, Piptatherum miliaceum, and Artemisia herba-alba) growing in the vicinity of a Pb-(Ag)-Zn mine and asses their phytoextraction and phytostabilization potential. The results indicated that very high soil contamination was found for Zn, Fe, Al, Pb, Cd, As, Se, and Th, considerable to moderate contamination for Cu, Sb, Cs, Ge Ni, Cr, and Co, and low contamination for Rb, V, Sr, Zr, Sn, Y, Bi and U in the study area, dependent of sampling place. Available fraction of PTEs and REEs in comparison to total concentration showed a wide range from 0% for Sn to more than 10% for Pb, Cd, and Mn. Soil properties such as pH, electrical conductivity, and clay content affect the total, available, and water-soluble concentrations of different PTEs and REEs. The results obtained from plant analysis showed that the concentration of PTEs in shoots could be at a toxicity level (Zn, Pb, and Cr), lower than toxic but more than sufficient or natural concentration accepted in plants (Cd, Ni, and Cu) or at an acceptable level (e.g., V, As, Co, and Mn). Accumulation of PTEs and REEs in plants and the translocation from root to shoot varied between plant species and sampling soils. A. herba-alba is the least efficient plant in the phytoremediation process; P. miliaceum was a good candidate for phytostabilization of Pb, Cd, Cu, V, and As, and S. oppositifolia for phytoextraction of Zn, Cd, Mn, and Mo. All plant species except A. herba-alba could be potential candidates for phytostabilization of REEs, while none of the plant species has the potential to be used in the phytoextraction of REEs.

The capacity of Plectranthus sp. to perform phytoremediation on heavy metal mercury (Hg) in the tailing of gold processing industries

“…2023 , he stabilizing action of plant roots reduces the mobility and bioavailability of pollutants, which in turn lessens the harmful impacts of metals on the environment [38]. [29], [39]. BCF and BAC values of Plectranthus sp.…”

“…and the types of treatments that have TF or BCF and BAC values >1 are summarized in Table 4. The accumulator properties of Hg in these 3 treatments, are classified as moderate, because BCF and BAC value is in range value 0.1-1 [29], [39]. Table 4 shows the possible uses of Plectranthus sp.…”

Remediation of heavy metals by native plant species grown in Iran’s richest gold mine and study of plants’ pollution tolerance strategies

“…Various plant species with different capabilities in the uptake, accumulation, and extraction of heavy metals are widespread throughout the world (Shtangeeva, 2021). Information about plantsoil relationships, the concentration of metals in plants, and their remediation potential is growing continuously (Azizi, et al, 2023).…”

Use of aided phytostabilization facilitate the production of aromatic plants in mining wastes as an environmental and socieconomic rehabilitation strategy

“…En general, una de las características de los depósitos mineros localizados en el Distrito Minero de Cartagena-La Unión es la acumulación de concentraciones elevadas de metal(oide)s (Azizi et al, 2023;Martínez-Carlos et al, 2022;Shahrokh et al, 2023b), Concretamente, los metal(oide)s que presentaron mayor concentración en el conjunto de las parcelas analizadas en este estudio fueron el Zn y el Pb, seguidos de As y Cd (Figuras 4.3.1. y 4.3.2).…”

“…En comparación con los suelos naturales de la Sierra Minera que presentan concentraciones de 1226 -3709 mg kg -1 (Martínez-Martínez et al, 2013), los suelos de este estudio acumulan menor cantidad de este metal. Sin embargo, el estudio realizado por (Azizi et al, 2023) en otro distrito minero de la Región de Murcia, en Mazarrón, mostró mayores concentraciones de Pb en las muestras de suelo procedentes de depósitos mineros, superando el valor de 2500 mg kg -1 .…”