Current Environmental Engineering - Volume 4, Issue 1, 2017

Background: Soil contamination by toxic metals leads to major ecological and human health problems. The metals are non-degradable and accumulate in the environment. It is therefore necessary to source for sustainable measures to remediate contaminated soils. Phytoremediation is a promising technology that involves the use of green plants to tidy up sites sullied with toxic pollutants. This paper highlights weeds as plants to be exploited for the remediation of heavy metal contaminated soils. Methods: Research materials related to phytoremediation techniques and soil contamination by heavy metals are reviewed. The sources and toxicity of these metals are indicated. The various techniques for phytoremediation, properties of plants that are suitable for use and some weeds with the potential are outlined. Results: Soil contamination by heavy metals is an issue of serious concern mostly in the developing countries. It is a threat to plants and underground water, and there is a possibility for these toxic substances to be incorporated into the food chain. Some of these metals accumulate in body organs and cause severe damage. Conventional technologies for the remediation of soils contaminated by these toxic metals are costly and time consuming. Several species have been reported with phytoremediation potential, though information is scarce in developing countries. Conclusion: Phytoremediation is a feasible method to clean up contaminated soils because it is sustainable, inexpensive and environmentally safe. Weeds are fast growing plants that produce high biomass and this makes them suitable for use in phytoremediation.

Phytoremediation technology involves the role of plants for removing various contaminants from the environment. Both aquatic and terrestrial plant species have shown capacity for removing inorganic and organic contaminants from the environment. Recent studies demonstrated that medicinal and aromatic plants possess potential to accumulate/remove various contaminants from the environment. Hence medicinal herbs also offer a good and sustainable option for removal of contaminants from the environment and remediation of contaminated sites.

The utilization of terrestrial, aquatic and semiaquatic plants to remediate contaminated soil or water is known as phytoremediation. This innovation has developed as a more practical, noninvasive, and freely satisfactory approach to address the expulsion of ecological contaminants. Plants can be utilized to aggregate inorganic and natural contaminants, to metabolize natural contaminants, and to energize microbial load of natural contaminants in the root zone. This short review gives a knowledge into phytoremediation of water bodies. It goes ahead to talk about phytoremediation as a ecofriendly purifying device. The diverse phytoremediation systems, the procedures through which plants purify water bodies and the nature of plants reasonable for phytoremediation are also analyzed besides other things.

Background: Arsenic (As) harming is spreading all through the world where a large number of individuals are influenced by arsenicosis, and millions are possibly at danger, and this has prompted recharged enthusiasm for the issue of As all through the world. Arsenic (As) is found naturally in soil, water, rocks and air. It comes into the terrestrial and aquatic ecosystems through both the combination of natural activities such as weathering, volcanic eruptions, biological activity, and anthropogenic activities. Arsenic is a redox metal, which accumulates in different parts of plants and animals and causes toxic effects, instantly by injuries and rupturing the cell organization and by replacing the indispensable nutrients. Numerous physicochemical and biological procedures have been produced to expel arsenic from defiled environment. Phytoremediation has been recommended as a financially savvy strategy to tidy up defiled soils. Methods: Many physiochemical and biological methods have been proposed for remediation of arsenic from the polluted environment. Phytoremediation shows a great potential for future development due to its ecofriendly nature and cost effectiveness. To improve this process, various techniques are recommended for enhanced phytoremediation. Results: New strategies are required to upgrade phytoremediation effectiveness. Several techniques are used like abiotic (chelating agents, phosphorus, organic matter) and biotic (bacteria, mycorrihza) amendments to increase the phytoremediation potential of plants. Apart from this genetic engineering also plays an important role in increasing the phyotremedaition potential of plants. Conclusion: Arsenic hyperaccumulators have received increased attention in recent years, due to the potential of these plants for phytoremediation of arsenic contaminated soils. This is an efficient and cost-effective technology for arsenic remediation. Biomass is considered as an important factor for phytoremediation which can be enhanced by biotic and abiotic amendments. Now days many researches are focusing on the physiological mechanisms of hyperaccumulation which will provide a better understanding to the mechanism of plants to detoxify arsenic stress. Genetic engineering technology can also be considered in increasing the accumulation capability of plants.

Phytochelators are metal chelating exudates secreted by plant roots or microbes into the rhizosphere. These include many diverse compounds such as Low Molecular Weight Organic Acids (LMWOA’s), phytins, siderophores, phytochelatins, metallothioneins, etc. They are known to act as effective soil amendments by increasing metal diffusion rates in the soil and help in their movement into the plants, thereby fastening remediation of contaminated land sites. This review aims at discussing all the major types of phytochelators and their mode of action in supplementing the process of phytoremediation.

Background: Among problem soils, saltification is one of the main issues, which rigorously influence the agricultural yield globally. Owing to saltification, over half a billion hectares of available land almost remain unused in crop production. About 20% of the irrigated area of the globe is seemingly exaggerated by salinization of soil. Hence, there is a necessity to search new ways to recover salt affected soils with the intention that these soils could sustain greatly prolific and consequential land-use schemes to convene the existing threats of worldwide food safety measures. Even though enduring answer of saltification needs a perfect drainage system to control the rising water table, but due to high cost and energy consumption this option is not feasible at large scale in large areas. Biological method such as Phytoremediation, i.e., plant-based approaches to management of worsening soils is a suitable choice. Methods: Available literature on the topic from the last few years and online accessible scientific matter was conferred while scripting this review article to find out the historical background and present scenario relevant to phytoremediation. Almost all the plants which have been suggested as a potential option for reclamation of problematic land are complied. Results: On the basis of collected information; commonly point out that both halophytes and glycophytes are remarkable candidates as tools for phytoremediation. They have highly intricate but balanced mechanism to combat the soil pollutants and waste due to toxic waste by heavy metals, organic contaminants, and radio nuclides from a variety of farming and industrialized negligence This practice can be improved by adding up soil modifications that augment metal accessibility & make possible the metal and salt uptake by plants, thus escalating remediation impending significantly Conclusion: Despite many reports yielding the significant phytoremedial efficacy of plants, additional exploration is desirable to identify more plants because many of the useful plants are still unexplored for this procedure. Preceding acquaintance needs relevance and advancement into tools which can be used easily by the common farmers without any uncertainty. Development of transgenic plants for this particular purpose is an area of future work.

Background: Global industrialization has badly effect on environment and the entire biospheres. This distraction of the ecosystem has a hazardous effect on health of human and other organisms. Efforts should be made for dense vegetation of heavy metal bioaccumulation plants at the contaminated soil so that they can remove pollution and also give eco-green pleasant sense. Methods: In the present research, effects of increasing concentrations of heavy metals in soil, on species in vitro was investigated and results showed that Datura inoxia can tolerate higher concentrations of four toxic heavy metals like Pb, Cd, Cr and Ni indicating its phytoremediation potential. Results: The study revealed that for each metal Datura inoxia had given better response in case of survival, which indicates its importance as a plant suitable for phytoremediation of heavy metal contaminated area. Conclusion: Datura inoxia was proved to be a potent plant species for heavy metal removal studies. The specialty of the plant was that in vitro plants cultured on M. S. medium were able to survive on higher concentrations of heavy metals. The Datura inoxia represent an identical plant suitable for phytoremediation which ranked among the highest according to their heavy metal accumulation trials and the tissue culture studies.

Background: The pattern of heavy metal accumulation in stubborn weed (Sida acuta) was studied for a period of 90 days in a pot experiment. Methods:15 kg of soil in punctured pots was mimicked with two liters of utilized greasing up oil to accomplish 13.3% (w/w) contamination level while pots serving as control contained 15 kg of soil without utilized greasing up oil. The substantial metal focus was lower in the dirt soil with headstrong weed (STW) than the oil - free (OFS) and soil contaminated with utilized greasing up oil without resolved weed (OPS). Results: There were no critical contrasts (p>0.05) in the centralizations of Iron, zinc, nickel and copper in the pot test. In the tissues of stiff-necked weed, convergence of metals demonstrated higher measures of copper in the roots and shoots took after by iron and lead. This study demonstrated that in unshakable weed, iron aggregated in the shoots while copper gathered in the bases of the determined weed. Conclusion: The examples of metal fixation in the leaves of the plants developed in utilized greasing up oil dirtied soil vary from leaves of plants developed being used greasing up without oil soil.