Ecological Potential of Plants for Phytoremediation and Ecorestoration of Fly Ash Deposits and Mine Wastes

Abstract

Fly ash generates as the result of coal combustion in thermoelectric power stations whereas ore mining activities produce mine waste-rock and tailings worldwide. High concentrations of metal(loid)s and organic pollutants in fly ash and mine wastes are released into soil, air, and water presenting a global threat to the surrounding environment and human health. The environmentally sound management of fly ash and mine wasterock and tailings includes monitoring stability of the dam construction and seepage flowrate, prevention of water erosion and dust spreading, reducing the footprint of the management facilities and successful restoration/revegetation. Harsh conditions prevailing on fly ash and mine deposits are unfavorable mechanical composition and pH, high concentrations of soluble salts, lack of nitrogen and phosphorous, reduced number of microorganisms and fungus, toxic concentrations of As, Au, Ag, B, Cu, Cd, Cr, Hg, Mn, Mo, Ni, Pb, Zn, and the presence of PAHs and PCBs. The review addresses phystostabilization, phytoextraction, rhizodegradation, and phytodegradation as main phytoremediation green technologies which use plants to clean up the contaminated area to safe levels. Establishment of the self-sustaining vegetative cover on fly ash and mine deposits is crucial for recovering ecosystem health, stability, and resilience. Therefore, here we have discussed the essential role of native plants in the ecorestoration process on waste deposits. Additional emphasis is given to the evaluation of plant adaptive response to pollution stress. This review presents a current knowledge in phytomanagement of fly ash deposits, mine waste-rock and tailings. Also, it provides a new frontier in restoration physiology where physiological and biochemical tools can be used to predict plant response to stressors and success of restoration projects.

The phytoremediation potential of non-edible oil-producing plants for gold mine tailings

“…A combination of BCF < 1 and TF ≥ 1 or BCF and TF < 1 is indicative of plant's potential as phytostabilizer and refers to its metal tolerance strategy, that is exclusion (Gajić et al 2018). Exclusion is one of the plant strategies to maintain lower rate of heavy metal absorption and accumulation (Seregin and Kozhevnikova 2011;Gajić et al 2018). The low value of BCF and FT shows that the plant has limitations in absorbing and accumulating metals in its biomass (Yoon 2006).…”

Phytoremediation Potential, Photosynthetic and Antioxidant Response to Arsenic-Induced Stress of Dactylis glomerata L. Sown on Fly Ash Deposits

“…This is achieved by using excluders which are able to immobilize pollutants in the substrate or plant roots [6]. Therefore, plants with a different combination of bioconcentration factor (BCF) and translocation factor (TF) (BCF < 1 and TF <1; BCF < 1 and TF > 1; BCF > 1 and TF < 1) show a high phytostabilization potential and represent excluders, because they possess mechanisms that maintain low uptake of soil-metal(loid) content and low shoot-metal content [7]. Furthermore, sowing a mixture of grasses and legumes and planting of shrubs and trees on fly ash deposits that are good phytostabilizators of metal(loid)s are crucial for efficient ecological restoration.…”

“…Furthermore, sowing a mixture of grasses and legumes and planting of shrubs and trees on fly ash deposits that are good phytostabilizators of metal(loid)s are crucial for efficient ecological restoration. These plants also provide green cover that is able to stabilize ash, prevent erosion by wind, decrease mobility and toxicity of toxic elements in the environment and provide organic matter which can bind contaminants [7][8][9][10][11][12][13][14].…”

Morphological Responses and Gene Expression of Grain Amaranth (Amaranthus spp.) Growing under Cd

“…Phytomanagement can cover the mechanisms of phytoextraction and phytostabilisation. The translocation factor (TF) defines the relationship between the content of the metal in the leaves and its content in the root, providing the information about the efficiency of plant to transport metal(s) from roots to leaves [32]. Therefore, TF determination is important for assessing the plant's phytoremediation potential.…”