Phytoremediation of Heavy Metals Contaminated Soils Through Transgenic Plants
01 Jan 2016-pp 345-391
TL;DR: In this article, the use of plants and their associated microbes to remedy contaminated soils, sediments, and groundwater, is emerging as a cost-effective and environment friendly technology, using different plant processes and mechanisms normally involved in the accumulation, complexation, volatilization, and degradation of organic and inorganic pollutants.
Abstract: The contamination of the environment with toxic metals has become a worldwide problem. Metal toxicity affects crop yields, soil biomass, and fertility. Soils polluted with heavy metals pose a serious health hazard to humans as well as plants and animals, and often requires soil remediation practices. Phytoremediation, the use of plants and their associated microbes to remedy contaminated soils, sediments, and groundwater, is emerging as a cost-effective and environment friendly technology. Phytoremediation uses different plant processes and mechanisms normally involved in the accumulation, complexation, volatilization, and degradation of organic and inorganic pollutants. Certain plants, called hyperaccumulators, are good candidates in phytoremediation, particularly for the removal of heavy metals. Phytoremediation efficiency of plants can be substantially improved using genetic engineering technologies. Recent research results, including overexpression of genes whose protein products are involved in metal uptake, transport, and sequestration, or act as enzymes involved in the degradation of hazardous organics, have opened up new possibilities in phytoremediation of heavy metal-contaminated soils.
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TL;DR: The addition of CA improved the plant physiology and enhanced the antioxidant enzymes activities to overcome Pb and Hg induced oxidative damage and electrolyte leakage and revealed that T. latifolia showed greater tolerance towards Hg and accumulated higher Hg in all parts compared with Pb.
34 citations
TL;DR: In this paper, the authors evaluated the usefulness of Phalaris arundinacea, Salix viminalis and Zea mays to the phytoremediation of the soil contaminated with nickel.
Abstract: The aim of this study was to evaluate the usefulness of Phalaris arundinacea, Salix viminalis and Zea mays to the phytoremediation of the soil contaminated with nickel. A 2-year microplot experiment was carried out with plants growing on Ni-contaminated soil. Microplots (1 m2 × 1 m deep) were filled with Haplic Luvisols soil. Simulated soil contamination with Ni was introduced in the following doses: 0—no metals, Ni1—60, Ni2—100 and Ni3—240 mg kg−1. The phytoremediation potential of plants was evaluated using a tolerance index, bioaccumulation factor, and translocation factor. None of the tested plants was a species with high Ni phytoremediation potential. All of them demonstrated a total lack of usefulness for phytoextraction; however, they can be in some way useful for phytostabilization. Z. mays accumulated large amounts of Ni in the roots, which made it useful for phytostabilization, but, at the same time, showed little tolerance to this metal. For this reason, it can be successfully used only on soils medium-contaminated with Ni, where a large yield decrease did not occur. Its biomass may be safely used as cattle feed, as the Ni transfer from roots to shoots was strongly restricted. P. arundinacea and S. viminalis accumulated too little Ni in the roots to be considered as typical phytostabilization plants. However, they may be helpful for phytostabilization due to their high tolerance to Ni. These plants can grow in the soil contaminated with Ni, acting as a protection against soil erosion or the spread of contamination.
24 citations
Cites background from "Phytoremediation of Heavy Metals Co..."
...Plants used in phytostabilization reduce the amount of water percolating through the soil, thus minimizing the hazardous leaching and preventing soil erosion, and hence, stop the distribution of toxic metals to other areas (Srivastava 2016; Thakur et al....
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01 Jan 2019
TL;DR: In this paper, the development of genetically modified (GM) plant species has been regarded as a next-generation technology to generate plant tolerance against As stress and even phytoremediation of As from contaminated soils.
Abstract: Arsenic (As) contamination is a global problem causing massive damage to crops and the quality of human life. As is a widespread heavy metal pollutant prevalent in the groundwater. This contaminated groundwater is often used for watering plants and crops during agricultural seasons. As toxicity deteriorates crop production and sometimes even accumulates in the food grains and edible parts. These pass on to the consumers (humans) in the next trophic level and exhibit serious effects of biomagnification. Health risks from As exposure in humans have often been compared to those from tobacco smoke and radon in homes. The development of genetically modified (GM) plant species has been regarded as a next-generation technology to generate plant tolerance against As stress and even phytoremediation of As from contaminated soils. Successful implementation of the transgenic technology in this field requires proper understanding of the intricate mechanisms of As tolerance, accumulation, As(V) reduction, As sequestration, As translocation through the vascular system, and As phytovolatilization.
13 citations
01 Jan 2020
TL;DR: In this article, the authors have focused on the various technologies used to remove the metal pollutants from natural resources especially from water and soil, and recognized as a well-established approach to remediate the toxic effects induced by them.
Abstract: Heavy metals are considered as the major classes of a contaminant in nature. Heavy metal contamination from fertilizers, metal mining, and industrial activities leads to toxic effects on humans and other organisms. Although the toxic effects of these elements have been recognized for a long time, exposure to these elements continues. The toxic effects induced by them can lead to death in humans. Several advanced strategies have primarily employed to tidy up the surrounding from toxicants; however, most of the strategies are considered as problematic when getting results. The current concerns regarding the contamination due to heavy metal deposition have introduced the novel advanced technologies to detect the presence of them from soil and wastewater. Several plants have been recognized as potent herbs since they are able to absorb these toxicants. The phytoremediation techniques usually uptake the heavy metals from the soil and wastewater and recognized as a well-established approach to remediate the toxic effects induced by them. The plant-based techniques have some advantages over the conventional strategies. Therefore, the present research has focused on the various technologies used to remove the metal pollutants from natural resources especially from water and soil. These affordable and effective technologies are potentially cost-effective and environmental friendly.
9 citations
01 Jan 2019
TL;DR: In the recent past, various reports suggest that metal accumulation and plant tolerance mechanisms could be increased or manipulated by using different genetic engineering approaches as discussed by the authors, which makes it possible to develop metal tolerant plants designed for site-specific conditions that are highly effective for remediation of heavy metals from the polluted site.
Abstract: Various natural and technogenic activities have increased heavy metals pollution in the environment and caused a serious threat to the plant and other living organisms. Trace elements (TEs) like lead (Pb) and zinc (Zn) accumulation, induced toxicity, tolerance response, and their detoxification mechanisms in several plants have been discussed thoroughly during the last few decades. TEs once accumulated lead to the generation of excess reactive oxygen species (ROS), which may cause an alteration in cellular metabolism and affect overall plant performances. Despite causing toxicity, these ROS molecules also trigger various signaling cascades and activate the plant’s defense system. This system encircles enzymatic, nonenzymatic, and plant metabolites. In the recent past, various reports suggest that metal accumulation and plant tolerance mechanisms could be increased or manipulated by using different genetic engineering approaches. Genetic manipulation or metal tolerant transgenic plants have significantly attained much scientific attention for the development of phytoremediation technology. These approaches make it possible to develop metal tolerant plants designed for site-specific conditions that are highly effective for remediation of heavy metals from the polluted site.
3 citations
References
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TL;DR: The principles, advantages and disadvantages of immobilization, soil washing and phytoremediation techniques which are frequently listed among the best demonstrated available technologies for cleaning up heavy metal contaminated sites are presented.
Abstract: Scattered literature is harnessed to critically review the possible sources, chemistry, potential biohazards and best available remedial strategies for a number of heavy metals (lead, chromium, arsenic, zinc, cadmium, copper, mercury and nickel) commonly found in contaminated soils. The principles, advantages and disadvantages of immobilization, soil washing and phytoremediation techniques which are frequently listed among the best demonstrated available technologies for cleaning up heavy metal contaminated sites are presented. Remediation of heavy metal contaminated soils is necessary to reduce the associated risks, make the land resource available for agricultural production, enhance food security and scale down land tenure problems arising from changes in the land use pattern.
2,826 citations
TL;DR: This review article comprehensively discusses the background, concepts and future trends in phytoremediation of heavy metals.
2,718 citations
01 Jan 1989
TL;DR: Phytochemical studies suggest that hyperaccumulation is closely linked to the mechanism of metal tolerance involved in the successful colonization of metalliferous and otherwise phytotoxic soils.
Abstract: This paper reviews the plant geography, ecology, metal tolerance and phytochcmistry of terrestrial higher plants which arc able to accumulate metallic elements in their dry matter to an exceptional degree. The review is limited to the elements Co, Cu, Cr, Pb. Mn. Ni and Zn. Hyperaccumulators of Co, Cu, Cr, Pb and Ni arc here defined as plants containing over 1000 u.g/g (ppm) of any of these elements in the dry matter; for Mn and Zn, the criterion is 10,000 u.g/g (1%). A unifying feature of hypcraccumula ting plants is their general restriction to mineralized soils and specific rock types. Lists of hypcraccumula ting species arc presented for the elements considered. These suggest that the phenomenon is widespread throughout the plant kingdom. For example, 145 hyper-accumulators of nickel are reported: these arc distributed among 6 supcrordcrs, 17 orders, and 22 families and include herbs, shrubs and trees from both the temperate and tropical zones. Although some phylogcnetic relationships emerge, the evolutionary significance of metal hyperaccumulation remains obscure. Phytochemical studies however suggest that hyperaccumulation is closely linked to the mechanism of metal tolerance involved in the successful colonization of metalliferous and otherwise phytotoxic soils. The potentialities of hyperaccumula ting plants in biorccovcry and soil detoxification arc indicated.
2,341 citations