Article

Phytoremediation of heavy metals from fly ash pond by Azolla caroliniana

June 2012
Ecotoxicology and Environmental Safety 82:8-12

DOI:10.1016/j.ecoenv.2012.05.002

Source
PubMed

Authors:

Babasaheb Bhimrao Ambedkar University

Abundance of naturally growing Azolla caroliniana (water fern) on the surface of metal enriched fly ash (FA) pond reflects its toxitolerant characteristics. Results indicate the efficiency of A. caroliniana for phytoremediation of FA pond because of its higher bioconcentration factor. The metal concentration ranged from 175 to 538 and 86 to 753mgkg(-1) in roots and fronds, respectively. Bioconcentration factor (BCF) values of all metals in root and frond ranged from 1.7 to18.6 and 1.8 to 11.0, respectively, which were greater than one and indicates the metal accumulation potential of A. caroliniana. Translocation factor (TF) ranged from 0.37 to 1.4 for various heavy metals. The field result proved that A. caroliniana is a potential accumulator for the examined heavy metals and can be used for phytoremediation of FA pond.

Biochemical responses and phytoremediation potential of Azolla imbricata (Roxb.) Nakai in water and nutrient media exposed to waste metal cutting fluid along with temperature and humidity stress

Article

Feb 2023

Phytoremediation of metals from water (WM) and nutrient (NM) media exposed to waste metal cutting fluid (WMCF) along with temperature (T) and humidity (H) stress was tested using Azolla imbricata (Roxb.) Nakai. In the absence of WMCF, biomass was higher in NM than in WM during all tests. Surprisingly, opposite results were noted in the presence of WMCF, with growth failing at exposure to > 0.1% and > 0.5% in NM and WM, respectively. Further, correlation analysis of the growth data following WM exposure revealed that biomass was affected positively by T and negatively by H and metal accumulation. Simultaneously, metal accumulation was affected negatively by T and positively by H. The average accumulations of Al, Cd, Cr, Fe, Pb, and Zn across all T/H tests were 540, 282, 71, 1645, 2494 and 1110 mg·kg-1, respectively. The observed bioconcentration factor indicated that A. imbricata acts as a hyperaccumulator or accumulator of Zn (>10) and as either accumulator (>1) or excluder (<1) of the other metals. Overall, the phytoremediation performance of A. imbricata in multi-metal-contaminated WMCF was high in WM under all environmental conditions. Therefore, the use of WM is an economically feasible approach for the removal of metals from WMCF.

Interspecific Variability in Growth Characteristics and Phytoremediation of Cu by Free-Floating Azolla Macrophytes

Article

Full-text available

Jan 2023

The phytoremediation potential of aquatic plants, particularly for Cu, is scarcely reported in the pertinent literature. In this regard, differential growth behavior and phytoaccumulation ability of three free-floating Azolla species (A. japonica, A. pinnata, and A. hybrid) were evaluated in a climatically controlled (a temperature of 25/20 °C, light/dark 16/8 h, a light intensity of 60 µmol m−2 s−1, and a relative humidity of 65%) microcosm study. Azolla plants were exposed to solutions having three Cu concentrations (0, 3, and 6 mg L−1) under two incubation periods (4 and 8 days). Different Cu treatments significantly reduced Azolla biomass during both incubation periods and A. pinnata was the most sensitive species. Azolla plants grown in aqueous solutions showed substantial variations in Cu removal capacity. Higher bioconcentration values displayed by Azolla plants indicated that these plants can be deployed as potential plants for Cu removal from Cu contaminated water. Nevertheless, the plants exposed to higher Cu concentrations displayed color changes and root detachment due to Cu phytotoxic effects which may also ultimately lead to plant death. Significant correlations between Cu removed from the aqueous solutions and Cu contents of plant biomass indicated that Cu phytoremediation by Azolla plants was due to the phytoaccumulation mechanism because the removed Cu from aqueous solutions was accumulated in plant biomass. Introduced Azolla species, i.e., A. hybrid, displayed comparable Cu removal efficiency with naturally grown Azolla species, i.e., A. japonica and A. pinnata. Tested Azolla species proved to be suitable candidates to remediate Cu contaminated water and can be deployed for phytoremediation.

Interspecific Variability in Growth Characteristics and Phytoremediation of Cu by Free-Floating Azolla Macrophytes

Article

Full-text available

Dec 2022

Sohaib Aslam

Green synthesis of ZnO, MgO and SiO2 nanoparticles and its effect on irrigation water, soil properties, and Origanum majorana productivity

Article

Full-text available

Apr 2022

The synthesis of different metal oxide nanoparticles (NPs) (e.g., ZnO, MgO and SiO 2 ) using green methods is a promising alternative to traditional chemical methods. In this work, ZnO, MgO, and SiO 2 NPs were prepared using lemon peel extract. The synthesized NPs were characterized using Fourier transform infrared spectroscopy, UV–Visible spectroscopy, X-ray diffraction, and transmission electron microscopy. Also, the effects of the green synthesis of different NPs on the irrigation water quality, the availability of some heavy metals in soil and plants, and the productivity of Origanum majorana (marjoram) were studied in detail. The obtained results showed that the addition of the NPs resulted in noticeable variations in the removal percentages of Cu ²⁺ and Fe ³⁺ from aqueous solutions. The maximum values obtained for the adsorption of Cu(II) on ZnO, MgO, and SiO 2 NPs within the pH values of 3–5 were 89.9%, 83.3%, and 68.36%, respectively. Meanwhile, the maximum adsorption values of Fe(III) at pH 3.3 were 82%, 80%, and 65% for ZnO, MgO, and SiO 2 NPs, respectively. Clearly, the application of the NPs effectively reduced the available Cu ²⁺ in the studied soil samples in the following order: Zn2 > Zn1 > Mg2 > Si2 > Mg1 > Si1 > C (control). The highest values of available Cu ²⁺ were observed in the control treatment, whereas the lowest values were obtained when Zn2 was added. The same tendencies were observed with substantial concentrations of Fe. The addition of NPs to the soil samples positively affected the plants' Cu ²⁺ uptake. The effects of NPs and the additions of Cu ²⁺ and Fe ³⁺ on the availability of nitrogen, phosphorus, and potassium (NPK) in the soil system were very completed and osculated from one treatment to another. The same tendencies were observed with the total concentration of NPK in plants.

Comparative analysis of trace and macro-element bioaccumulation in four free-floating macrophytes in area contaminated by copper smelter

Article

Jun 2021

Novelty statement: This is the first study that comprehensively compares Salvinia natans, Lemna minor, Lemna trisulca, and Azolla filiculoides growing in the field; industrially affected conditions in respect of elements contents, water-plant transfer, and bioaccumulation using statistical analyses and indexes and their suitability for phytoremediation was considered. Secondary aim of the study was to fill the gap in research on the impact of copper smelters on aquatic ecosystems. Although the manuscript describes a case study performed near copper smelter in Poland, due to the novel results and cosmopolitan distribution of the species and significant world-wide impact of industry on the environment the results may be interested to broad publicity and find substantial application.

Progress in the utilization of water hyacinth as effective biomass material

Article

Full-text available

Jul 2023
Environ Dev Sustain

Water hyacinth (Eichhornia crassipes) is considered a prospective free-floating aquatic plant potentially used to address current issues on food, energy, and the environment. It can grow quickly and easily in various tropical and subtropical environments as long as it has access to adequate light and water to support photosynthetic growth. Ecosystems are threatened by their invasive growth and remarkable capacity for adaptation. However, managing this plant can result in valuable products. This paper demonstrates particle technologies that might be used to utilize water hyacinths, including brake pads, fertilizer, bioenergy, animal feed, phytoremediation agents, bioplastics, and adsorbents. This study is accompanied by a discussion based on the conducted experiments and currently available literature, providing readers with a clearer understanding. Water hyacinth's capacity to absorb macro- and micro-nutrients, nitrogen, and phosphorus makes it a good plant for phytoremediation. The prospect of producing cellulose makes it prospective as a biomass energy source and livestock feeding. Further, it can be transformed into high-cellulose content particles for applications in bioplastics, brake pads, and adsorbents. The current reports regarding education of water hyacinth to student also were added. Finally, issues and suggestions for future development related to the use of water hyacinths are discussed. This study is expected to provide comprehensive knowledge on how to turn invasive water hyacinth plants into valuable products.

Preliminary studies on butterfly fauna of Narmada Nagar town, Dist. Khandwa M.P

Article

Full-text available

Jan 2023

Use of water hyacinth Eichhornia crassipes (MART.) Solms as phytoremediator in sewage fed aquaculture system

Research

Full-text available

Jan 2019

Wastewater management is of prime importance in the era of water deficiency for domestic purposes, agriculture and aquaculture. Phytoremediation involves utilisation of aquatic plants for remediating heavy metals and other pollutants from aquatic ecosystems. Efficiency of Eichhornia crassipes (Mart.) Solms as a potential bioremidiator in the Ramsar site Nalban bheri wetland of West Bengal is studied here. About 120 ha of area of Nalban bheri wetland were selected for the study, and were divided into three sections. Floating weed Eichhornia crassipes were maintained on water spread area and were screened for the presence and accumulation of heavy metals in plants, monthly. Bioconcentration factor and translocation factor were also estimated and discussed herewith. The present study recommends water hyacinth as a potential bioremidiator for controlling heavy metals in open freshwater bodies

CRISPR-assisted strategies for futuristic phytoremediation

Chapter

Jan 2022

Environmental pollution is increasing gradually and causing a serious impact on living organisms including humans. It can be reduced by microorganisms or plants that have biosynthetic pathways for the degradation or accumulation of environmental pollutants from soil and water. Lack of genetic components in natural microorganisms or plants lessens their ability to degrade or accumulate pollutants and hence is currently released at high rates. Recent advances in CRISPR-Cas9 technology have been used to edit the genome of microorganisms or plants in order to improve the degradation and accumulation efficiency to a higher rate for controlling environmental pollutants. We discuss recent developments in CRISPR-Cas9 based microorganisms and plant genome editing for bioremediation of environmental pollution in order to clean our environment for healthy animal life on earth.

Ecological restoration of fly-ash disposal areas: Challenges and opportunities

Article

Aug 2021

Fly ash is a prominent environmental by-product or residue that is produced during the combustion of coal for energy production in thermal power plant. The huge amount of fly ash generation is a global problem; still could not be found a safe and sustainable approach of fly ash disposal. The fly ash dumps not only creates air, water, and soil pollution but also poses noxious impact on human health by introducing toxins in food chain through biomagnification. The non-food vegetation cover can help to mitigate fly ash dump-related environmental health issues. However, alkaline pH, toxic metals, lack of microbes and pozzolanic properties of fly ash limit the plant growth. In this regard, ecological restoration of fly ash dumps through phytoremediation is a holistic approach. This review article focuses on the role of naturally occurring plants, tree plantation and microbial inoculation in ecological restoration of fly ash dumps and their role in the physicochemical changes of fly ash substrate. Application of organic material has been proved to establish vegetation cover on fly ash dumps as they provide essential nutrients to plant and microbial growth. Morphological, physiological and antioxidant response of plants grown on fly ash dumps are also discussed here in detail. Overall, this review summarises the different comprehensive approaches of fly ash dump restoration and compiles ways to convert barren fly ash dumps into useful dumpsites for deriving bioeconomy with phytoproducts. The outcomes of this learning are beneficial for classifying site-specific ecorestoration of fly ash dumps through integrated approach.

STUDY OF PHYSIO-CHEMICAL PROPERTIES, PROXIMATE AND ULTIMATE ANALYSIS OF BIODIESEL EXTRACTED FROM THREE FEED-STOCKS- MELIA AZEDARACH, RICE BRAN AND WATER HYACINTH

Article

Full-text available

Jan 2023

TARIM-VE-DOGA-BILIMLERINE-GUNCEL-BAKIS-

Book

Full-text available

Jul 2023

Tarım, Doğa bilimleri

TARIM-VE-DOGA-BILIMLERINE-GUNCEL-BAKIS-

Book

Full-text available

Jul 2023

Alleviating the toxic effects of Cd and Co on the seed germination and seedling biochemistry of wheat (Triticum aestivum L.) using Azolla pinnata

Article

Full-text available

May 2023
ENVIRON SCI POLLUT R

One of the most significant environmental challenges in the twenty-first century is heavy metal pollution. The potential use of fresh Azolla pinnata to alleviate the toxic effects of Cd and Co on the germination measurements of wheat seeds (Triticum aestivum L.) and the biochemistry of seedlings was studied. Two concentrations (80 and 100 mg L⁻¹ solutions) of CdNO3 and CoCl2 were used before and after treatment with A. pinnata. The highest removal efficiency (RE) by A. pinnata was obtained on the fifth day, with a Cd RE = 55.9 and 49.9% at 80 and 100 mg L⁻¹, respectively. Cadmium and cobalt solutions reduced the germination percentage, and the measured variables of wheat seeds meanwhile increased the radicle phytotoxicity. In contrast, the presence of A. pinnata in the germination medium increased all the measured variables and decreased radicle phytotoxicity. At 80 and 100 mg L⁻¹, Cd significantly reduced the fresh and dry biomass, and height of wheat seedlings after 21 days of cultivation compared to Co. Cadmium and high concentrations of cobalt increased the contents of H2O2, proline, MDA, phenolic, and flavonoid compounds. The application of treated Cd and Co solutions by A. pinnata showed a decrease in H2O2, proline, phenolic, and flavonoid compounds levels accompanied by a reduction in catalase and peroxidase activities compared to the control. This study showed the positive role of A. pinnata in alleviating the metal impacts, particularly Cd, on the seedling growth of wheat and its germination.

Heavy Metals Removal from Domestic Sewage in Batch Mesocosm Constructed Wetlands using Tropical Wetland Plants

Article

Full-text available

Feb 2023

Constructed wetlands are an affordable and reliable green alternative to conventional mechanical systems for treating domestic sewage. This study investigates the potential of 14 tropical wetland plant species for removing heavy metals from domestic sewage through the bioconcentration factor (BCF), translocation factor (TF), enrichment factor (EF), and geoaccumulation index (Igeo) using batch mesocosm studies. Plants with BCF > 1 and TF > 1 are classified as phytoextractors, while species with BCF > 1 and TF < 1 are phytostabilisers. The results indicate that 11 out of 14 species are magnesium phytostabilisers, 10 are calcium phytoextractors, and no plant species demonstrate ferrum phytoextraction properties. As for manganese phytoremediation, only three species depicted phytoextraction and phytostabilisation properties. The enrichment factor (EF) for all of the studied metals with ferum as a reference metal in all of the soil samples decreased after the phytoremediation of domestic sewage experiments, indicating depletion to mineral enrichment (EF < 2). All of the soil samples are generally classified as uncontaminated based on Igeo indices. Based on the factors and indices, it is suggested that the plants may have facilitated heavy metal removal from domestic sewage through uptake into the plant tissues from the roots.

Insight to chromium homeostasis for combating chromium contamination of soil: Phytoaccumulators-based approach

Article

Feb 2023

Chromium (Cr) is a naturally occurring, carcinogenic heavy metal that has become a pressing concern in recent decadesfor environmentalists. Due to high anthropogenic activities, the concentration of Cr has crossed the environmental threshold levels and consequently contaminated soil and water. The high solubility of Cr ions in the groundwater results in its high uptake by the plants leading to phytotoxicity and yield loss. The dearth of efficient and cost-effective treatment methods has resulted in massive chromium pollution. However, some phytoaccumulators capable of accumulating Cr in high amounts in their shoots and then performing their metabolic activity typically have bdseen identified. Chromium bioremediation using phytoaccumulators is very contemplative due to its eco-friendly and cost-effective outcome. These accumulators possess several mechanisms, such as biosorption, reduction, efflux, or bioaccumulation, naturally or acquired to counter the toxicity of Chromium. This review focuses on the detoxification mechanism of Cr by the phytoaccumulator species, theirresponses against Cr toxicity, and the scope for their application in bioremediation. Besides, Cr bioavailability, uptake, distribution, impairment of redox homeostasis, oxidative stress, and phytotoxicity imposed on the plants are also summarized. Further, the knowledge gap and prospects are also discussed to fill these gaps and overcome the problem associated with the real-time applicability of phytoaccumulator-basedbioremediation.

Utilization of Indole Acetic Acid with Leucadendron rubrum and Rhododendron pulchrum for the Phytoremediation of Heavy Metals in the Artificial Soil Made of Municipal Sewage Sludge

Article

Full-text available

Dec 2022

The development of phytoremediation by garden plants is an effective way to deal with the dilemma of municipal sewage sludge disposal. In this study, two ornamental plants were used as phytoremediation plants to rehabilitate heavy-metal-contaminated municipal sewage sludge in field experiments, and the role of exogenous phytohormone IAA was also tested. Ornamental plants Loropetalum chinense var. rubrum (L. rubrum) and Rhododendron pulchrum (R. pulchrum) adapted well to the artificial soil made of municipal sewage sludge, and the concentrations of Cu, Zn, Pb, and Ni were decreased by 7.29, 261, 20.2, and 11.9 mg kg−1, respectively, in the soil planted with L. rubrum, and 7.60, 308, 50.1, and 17.7 mg kg−1, respectively, in the soil planted with R. pulchrum, accounted for 11–37% of the total amounts and reached significant levels (p < 0.05), except Cd. The concentration of Pb in all parts of the two ornamental plants was increased, as well as most heavy metals in L. rubrum root. As a result, three months after transplant, the phyto-extraction amounts in L. rubrum were 397, 10.9, and 1330 μg for Ni, Cd, and Pb, respectively, increased by 233% to 279%. The phyto-extraction amount in R. pulchrum were 1510, 250, and 237 μg for Zn, Pb, and Cu, respectively, increased by 143% to 193%. These results indicated a potential to remediate heavy metals of the two ornamental plants, especially L. rubrum. The results of correlation analysis implied that the interaction of heavy metals in the plant itself played an important role in the uptake of heavy metals. This seemed to explain why applying IAA in the experiment had little effect on plant growth and phytoremediation of heavy metals. This study provided a green and feasible idea for the proper disposal of municipal sewage sludge.

Wastewater Treatment by Azolla: A review

Article

Full-text available

Jun 2022

Water is vital for humans and other living things, but water pollution has become a significant issue today. Various anthropogenic agricultural, industrial, and home activities produce multiple organic and inorganic substances dissolved or suspended in water. The goal of wastewater treatment is thus twofold: to reduce water pollution while also maintaining the water supply to demand. It is based on the three 3 Rs: reduce, reuse, and recycle. However, many of the methods used are ineffective or expensive. As a result, water purification is a matter of great interest. Eco-friendly approaches are essential among the new technologies and techniques tested in wastewater treatment. Aquatic macrophytes treat water by accumulating harmful metals and nutrients. Like water filters, a variety of aquatic floats can be suggested. Azolla is one among them, and it has been used for decades. Researchers have discovered that Azolla can reduce Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), nitrogen, phosphorus, and heavy metal concentrations in wastewater; therefore, it can be utilized for wastewater treatment. Azolla also produces a lot of biomasses in wastewater. The use of Azolla in reducing eutrophication in lakes and streams and other benefits is discussed in this study. According to the literature, Azolla has a high growth rate, with a doubling date of 2-4 days. Azolla's cell wall is composed of pectin, which has a high affinity for the adsorption of organic substances. Azolla serves as a "biofilter" during wastewater treatment in this way.

A Review of Research on the Use of Selected Grass Species in Removal of Heavy Metals

Article

Full-text available

Oct 2022

Soil and air pollution are main problems posing a serious threat to human health. Traditional physical and chemical soil remediation methods affect the soil ecosystem and are rather costly. Since the main purpose of soil remediation is not only to remove pollutants but also to restore soil health, the method of phytoremediation is becoming extremely relevant. Phytoremediation is an environmentally friendly and natural process of removing pollutants from the environment. Cleaning up contaminated sites and enabling re-use without harming future users requires the implementation of environmentally friendly and economically attractive technologies. Phytoremediation does not adversely affect the structure and biological life of the soil. Concerning on-site cleaning in situ. Hyperaccumulator plants can accumulate heavy metals from the soil, which is the so-called phytoextraction. The ability of trees and shrubs to effectively remove solid particles from the air has also been proven. However, it is not always possible to grow large plants in polluted areas. Therefore, the main goal of the research was to explore previous studies on the phytoremediation capability of herbaceous plants, in particular, their phytoextraction capacity. Another major issue was to study the main methods of improving plant phytoextraction. The results obtained show that grass can be a good solution for natural ecosystem cleanup. It is also necessary to pay attention to the impact of phytoextraction-improving substances on soil health.

A Review of Research on the Use of Selected Grass Species in Removal of Heavy Metals

Article

Full-text available

Oct 2022

Tetiana Sladkovska

Crucial plant processes under excess of metals/metalloids and tolerance through omics approaches

Chapter

Full-text available

Jan 2022

In earth heavy metals are an integral part, they can be both essential and nonessential. Soils polluted with heavy metals (HMs) have become common due to increase in geologic and anthropogenic activities. Significant environmental pollutants such as lead, nickel, cadmium, cobalt, and mercury cause plant toxic impact; reducing productivity and posing hazardous threats to agri-ecosystems are thus significant environmental pollutants. It affects the growth of plant due to phyto-toxicity. HMs interfere with the seed germination, growth of the plant and production mainly related to plant system physiology, biochemistry and genetic elements. HMs have a significant impact on seeds, cause defects and decrease germination by affecting the digestion and mobilization of food reserves in germinating seeds leads to seed toxicity and productivity loss. Accumulation of HMs is greatly influences the morphology of plants by cell degeneration and thickening of cell walls. It increases in the amount of treacherous elements in vascular cylinder and even ruptures the parenchyma tissue. HMs impede the action of important enzymes and obstruct the plant biochemical aspect like photosynthesis, pigment synthesis and most commonly the inhibit electron transport chain which contribute to the generation of radicals cause oxidative damage. It also decreases the vegetative growth of plants and increases the sign of senescence. In soil HMs levels cause osmotic disturbances in plants, they are known for effects on root growth, transport of water and transpiration. It alters the profile of genomic DNA and increase the rate of DNA methylation. To consider above facts, this chapter discussed the effects of HMs on important plant processes and tolerance through omics approaches.

Wastewater Treatment by Azolla: A review

Article

Full-text available

Jun 2022

Prabhasha Jayasundara

Rhizobacterial - Plant Interaction Approaches that Enhance Plant Growth Under Abiotic Stress

Article

May 2022

The global concern is population growth and rising food demands. It is unavoidable to implement new agricultural productivity-enhancing practices. Plant growth-promoting rhizobacteria (PGPR) has showed promise as a sustainable agriculture approach. They have a critical function in increasing soil fertility, promoting plant growth, and suppressing phytopathogens in the development of environmentally friendly, long-term agriculture. Beneficial plant growth-promoting (PGPR) microorganisms can be used as effective biotechnological instruments to boost plant development in a variety of situations, including stressful ones. A rise in the occurrence of abiotic stresses, which have a negative impact on plant growth and productivity in major crops, has been seen all over the world. As a result of such stress elements, plant development will be reduced under stress conditions compared to non-stress ones. There is a growing global desire for effective, ecologically friendly methods to decrease the negative consequences of plant stress. The importance of plant-beneficial microbe interactions under such harsh conditions cannot be overstated. Plant growth-promoting rhizobacteria (PGPRs) are a good option for reducing these stressors and are now routinely used. Plants inoculated with PGPRs undergo morphological and biochemical changes that lead to greater tolerance to abiotic stressors. In this review article we focus on PGPRs, abiotic stress effects on plant growth and PGPRs mechanism in alleviating salinity, drought and heavy metal stress condition for plant growth

Phytoremediation of heavy metals assisted by plant growth promoting (PGP) bacteria: A review

Article

Full-text available

May 2015

Continued industrialization, agricultural practices, and other anthropogenic activities lead to heavy metals contamination. Heavy metals have severe toxic effects on plants, animals, and human health, and therefore their remediation is crucial. Among the various techniques used, phytoremediation is one of the safest, most innovative, and effective tools for the remediation of heavy metals. Phytoremediation of toxic metals and metalloids has been reported by researchers using a variety of plants. The efficiency of phytoremediation can be enhanced by the assistance of plant growth promoting (PGP) bacteria. These bacteria transform metals into bioavailable and soluble forms through the action of siderophores, organic acids, biosurfactants, biomethylation, and redox processes. In addition, PGP bacteria possess growth-promoting traits, including phosphorus solubilization, nitrogen fixation, iron sequestration, and phytohormone and ACC (1-aminocyclopropane-1-carboxylic acid) deaminase synthesis, which improve plant growth and increase plant biomass, in turn assisting phytoremediation. Our current review of the literature highlights the potential of PGP bacteria, which facilitate phytoremediation of heavy metals in contaminated areas.

Strategic management of contaminated water bodies: Omics, genome-editing and other recent advances in phytoremediation

Article

Full-text available

Mar 2022

Due to excessive industrialization, urbanization and rising level of pollutants, the water bodies are continuously exposed to diverse group of toxic pollutants whose concentration, chemical forms and bioavailability in the aqueous system are governed by natural geochemical cycles as well as human activities. Chemical form or species of these toxic compounds or heavy metals is governed by the prevailing specific physical and chemical parameters like pH, salinity, dissolved organics, hardness and sedimentary load which impacts their mobility, bio-availability and hence toxicity. To overcome the challenging situation, an increased emphasis has been given on in-situ innovative technologies like phytoremediation, capable of detoxification of contaminated water bodies. The use of inherent aquatic plants along with recent omics tools can improve their phytoremediation ability to a great extent. These plants have an extensive root system which can filter and immobilize sediments, contaminants, fertilizer and pesticide run-off thereby reducing water pollution. Thus, the assortment and improvement of plants phytoremediation ability using the modern biotechnological tools and techniques, can be a suitable approach for successful remediation of contaminated water bodies. This review article focuses on the different biotechnological strategems like omics, proteomics, genomics, metabolomics and CRISPR in order to ameliorate the phytoremediation potential of the aquatic plants. The recent ground-breaking advancements to achieve desired genetic modification uses, CRISPR technology, to transfer a target set of genes to be assimilated into the plant genome of interest. Two variants of this technology, i.e. CRISPR-Cas9 as well as CRISPR- Cpf1 can be used for producing knock-outs, making gene substitutions, and targeting transcription and its regulation in the particular plant genome, to improve its phytoremediation efficiency.

Buffer Green Patches around Urban Road Network as a Tool for Sustainable Soil Management

Article

Full-text available

Feb 2022

Urban areas are facing a range of environmental challenges including air, water and soil pollution as a result of industrial, domestic and traffic emissions. In addition, global climate change is likely to aggravate certain urban problems and disturb the urban ecology by increasing the frequency and severity of extreme weather events. In the context of urbanization growth and the consequent impact on the environment, there is a growing interest in maintaining urban soil quality and functions as they are the medium for green infrastructure development. Furthermore, urban soils are becoming one of the key factors in the delivery of many ecosystem services such as carbon storage, climate regulation, water flow regulation, etc. On the other hand, urban soils are well-known to be a major sink of air pollutants due to the wet and dry atmospheric deposition and recirculation. Soil has the ability to degrade some chemical contaminants but when the levels are high, urban soils could hold on large amounts and pose a risk to human health. A cost-effective technological solution is to use the ability of some plant species to metabolize, accumulate and detoxify heavy metals or other harmful organic or inorganic compounds from the soil layer. The establishment of urban lawns (grass covered surfaces) is a helpful, environmentally friendly, economically sustainable and cost-effective approach to remove contaminants from polluted soils (terrains), which also has some aesthetic benefits. In this paper, an overview of the benefits and limitations of urban lawn construction is presented. The focus is on the perspectives for sustainable management of urban lawns, especially as buffer green patches in the road network surroundings, that can represent strategies to provide ecological and social multifunctionality of urban soils, and thus, increasing their ecosystem services capacity. Specifically, the paper highlights (i) the possibilities for phytoremediation of urban soils, (ii) potential of some perennial grasses and (iii) key issues that should be considered in the planning and design of urban lawns.

Green Synthesis of Different Nanoparticles and its Effect on Irrigation Water and Soil Properties and Origanum Majorana Productivity

Preprint

Full-text available

Jan 2022

The term of nanotechnology has emerged recently in several fields of interest that refers to the researches and innovations that are concerned with making materials on a very small size close to the scale of atoms and molecules. In the present work, the effects of green synthesis of different nanoparticles on the quality of irrigation water, the availability of some heavy metals content in soil and the plant, and the productivity of Marjoram were studied in detail. The obtained results showed that the addition of nanoparticles (NPs) materials has resulted in noticeable variations in the removal percentages of Cu and Fe from aqueous solution. The maximum values obtained for adsorption of Cu (II) on ZnO, MgO, and SiO 2 NPs, within pH (3–5) were 89.9%, 83.3%, and 68.36%, respectively. Whereas, the maximum adsorption values of Fe (III) at pH 3.3 were 82%, 80%, and 65% for ZnO, MgO, and SiO 2 NPs, respectively. It was clearly seen that the effective of NPs application on reduction of the available Cu in the studied soil samples. The order of sequence for the effects of NPs application was found to take the following order Zn2 > Zn1 > Mg2 > Si2 > Mg 1 > Si1 > C (control). The highest values of the available Cu were observed in the control treatment, whereas the lowest values were obtained when Zn2 was added, and the same tendency was observed with the substantial concentrations of Fe. The addition of NPs to the soil samples had positively affected the Cu uptake via plant. The effects of NPs and the additions of Cu and Fe on the availability of NPK in the soil system were very completed and osculated from one treatment to another. The same tendency was observed with the total concentration of NPK in the plant.

An Assessment of the Phytoremediation Potential of Planted and Spontaneously Colonized Woody Plant Species on Chronosequence Fly Ash Disposal Sites in Serbia—Case Study

Article

Full-text available

Dec 2021

In this study, the potential of planted (Tamarix tetrandra Pall. ex M.Bieb. and Robinia pseudoacacia L.) and spontaneously colonized (Amorpha fruticosa L. and Populus alba L.) woody species for the phytoremediation of potentially toxic trace elements (TEs) such as As, B, Cr, Cu, Mn, Ni, Se, and Zn, from the chronosequence fly ash (FA) deposit lagoons (L1 and L2) at the ‘Nikola Tesla A’ Thermal Power Plant (TENT-A) in Serbia were analyzed. The differences in the pseodototal and bioavailable (DTPA-extractable) concentrations and mobility (AR index) of TEs in FA at the examined lagoons are a result of the time-conditioned influence of weathering (3 and 11 years respectively) and vegetation development on changing the basic physical and chemical properties of FA (texture, pH, EC, CEC, C, N, and bioavailable P and K) and its toxicity. This resulted in differences in the concentration of TEs in the roots and leaves of the examined plants at L1 and L2. All examined species accumulated Cr the most in the root (BAF > 1 and TF < 1), which suggests that they are good stabilizers of this element. Biological indices for As (BAF > 1 and TF < 1) identified T. tetrandra and A. fruticose as good stabilizers of As. P. alba stood out as accumulating the highest levels of B, Ni, and Zn, T. tetrandra the highest levels of Cu, Mn, and Se, and R. pseudoacacia the highest levels of As and B in leaves (BAF > 1; TF > 1), which makes them good extractors of these elements from the FA at TENT-A. However, due to toxic concentrations of As, B, Se, and Zn in their leaves, they are not recommended for the phytoremediation of the investigated lagoons through the process of phytostabilization. Under conditions of elevated total Cu and Ni concentration in FA, the content of these elements in the leaves of A. fruticosa at both lagoons were within the normal range. This, in addition to a good supply of essential Zn, the stabilization of As and Cr in the roots, an increase in BAF, and a decrease in TF for B with a decrease in its mobility in ash over time, singles this invasive species out as the best candidate for the phytostabilization of TEs in FA at the TENT-A ash deposit site.

Phytoremediation: A Sustainable Technology for Pollution Control and Environmental Cleanup

Chapter

Dec 2021

Increasing population and pollution has reached an alarming situation worldwide. Pollution of water bodies, soil, and agricultural land worldwide is deteriorating environmental and human health. Various physico-chemical techniques, pollution control rules, and safety standards all together are still unable to control the pollution at the desired level. The need of the hour is to move into the future with the adoption of sustainable technologies. This chapter summarises the progress of the sustainable aspects of phytoremediation in pollution control and abatement. Phytoremediation revolves around several approaches developed around the world during the few past decades. These include phytoextraction, phytovolatilisation, phytotransformation, etc. Though phytoremediation is still not commercialised at a large scale, it has obtained appreciation as a holistic approach with multiple benefits in removing environmental contaminates. The use of an economically important and local plant for phytoremediation technology would be a promising approach to generate income sources for the farmers and would help in the progress of technology. This chapter discusses various aspects of phytoremediation and future scenarios.

Phytoremediation ability of H. strobilaceum and S. herbacea around an industrial town

Article

Full-text available

Sep 2021

Contaminations of soil and water resources with various organic and inorganic compounds are of great importance on account of the close relationship between the living organisms and their feeding. That is due to direct impact in supplying food for living organisms in terms of environmental and human health aspects. In this regard, the present study aimed to investigate the phytoremediation potential of H. strobilaceum and S. herbacea in contaminated soils. For this purpose, soil and plant samples were collected from around the sewage channel in Eshtehard industrial region of Iran. Sampling started at the edge of the channel and ended in a distance of 500 m from the channel. The distance of 1000 m from channel was considered as the control point. ICP-OES was used for the measurement of heavy metals. The obtained results showed that the highest and lowest amounts of soil lead (Pb) were 17.6 and 2.33 mg kg−1, respectively. For Cadmium (Cd), the values ranged from 0.341 to 0.11 mg kg −1 at 21–50 cm depth for the control point. For the plants, the highest and lowest amount of Pb belonged to H. strobilaceum shoot (10.38 mg kg −1) and S. herbacea root (7.54 mg kg −1), respectively. The maximum (1.64 mg kg−1) and minimum (0.36 mg kg−1) Cd concentration was observed in the root and shoot of H. strobilaceum, respectively. In both species, Translocation Factor (TF) for Pb and Cd was greater than 1 and less than 1, respectively. Cd Bio Concentration Factor (BCF) in the roots of both species was estimated to be greater than 1 while for Pb, this index was smaller. Bio Accumulation Factor (BAF) in the shoots of Pb and Cd for both plants were lower and greater than 1, respectively. In general, the results revealed that the highest concentrations of Cd and Pb are absorbed and stored by the underground organs of H. strobilaceum and S. herbacea and these plants have the ability to remove Pb and Cd from contaminated soils.

Interactive effect of Meloidogyne incognita and fly ash on the growth, physiology, and antioxidant properties of carrot (Daucus carota L.)

Article

Full-text available

Jan 2022
ENVIRON SCI POLLUT R

Alternative methods are needed to replace chemical nematicides because they have the potential to damage beneficial soil microbial diversity. Therefore, the present work was done to elucidate the soil ameliorative, plant-growth-promoting, and nematicidal properties of fly ash. A random block-designed pot experiment was conducted during the period, December 2018–February 2019. Seeds of carrot (Daucus carota L.) were sown under natural conditions in clay pots containing a growth medium comprising of field soil amended with different levels of fly ash. Plants were inoculated with Meloidogyne incognita that were molecularly characterized using 18S and D2/D3 fragments of 28S rDNA and morphologically through perineal pattern arrangement. The results revealed that fly ash application improved the soil’s important physicochemical characteristics. The inoculation of M. incognita significantly reduced the plant growth, yield, and pigment content of carrot compared to the untreated uninoculated plants. Carrot grown in 15% fly ash (85:15 w/w field soil:fly ash) growth substrate had significantly (P ≤ 0.05) improved plant growth, yield, and pigment content as compared to the untreated inoculated plants. Moreover, the proline content and the activity of superoxide dismutase (SOD) and catalase (CAT) were enhanced by applying 15% fly ash. Fly ash amendment to the soil not only improved plant growth and yield but also reduced the gall index and egg mass index per root system of the carrot as well. Our results, therefore, suggest that 15% fly ash can be used in a sustainable way to improve the growth, yield, and resistance of carrot against the infection of M. incognita. Graphical abstract

Phytoremediation of Arsenic Contaminated Water Using Aquatic, Semi-Aquatic and Submerged Weeds

Chapter

Full-text available

Aug 2021

Arsenic (As) is the one the most toxic element present in earth which poses a serious threat to the environment and human health. Arsenic contamination of drinking water in South and Southeast Asia reported one of the most threatening problems that causes serious health hazard of millions of people of India and Bangladesh. Further, use of arsenic contaminated ground water for irrigation purpose causes entry of arsenic in food crops, especially in Rice and other vegetable crops. Currently various chemical technologies utilized for As removal from contaminated water like adsorption and co-precipitation using salts, activated charcoal, ion exchange, membrane filtration etc. are very costly and cannot be used for large scale for drinking and agriculture use. In contrast, phytoremediation utilizes green plats to remove pollutants from contaminated water using various mechanisms such as rhizofiltration, phytoextraction, phytostabilization, phytodegrartion and phytovola-tilization. A large numbers of terrestrial and aquatic weed flora have been identified so far having hyper metal, metalloid and organic pollutant removal capacity. Among the terrestrial weed flora Arundo donax, Typha latifolia, Typha angustifolia, Vetivaria zizinoids etc. are the hyper As accumulator. Similarly Eicchornea crassipes (Water hyacinth), Pistia stratiotes (water lettuce), Lemna minor (duck weed), Hyrdilla verti-cillata, Ceratophyllum demersum, Spirodella polyrhiza, Azola, Wolfia spp., etc. are also capable to extract higher amount of arsenic from contaminated water. These weed flora having As tolerance mechanism in their system and thus remediate As contaminated water vis-à-vis continue their life cycle. In this chapter we will discuss about As extraction potential of various aquatic and semi aquatic weeds from contaminated water, their tolerance mechanism, future scope and their application in future world mitigating As contamination in water resources.

Nanophytoremediation: An Overview of Novel and Sustainable Biological Advancement

Chapter

Full-text available

Jun 2021

Increased threat of metals simultaneous to the biota well-being and the environs is continually causing a major apprehension worldwide. The phytoremediation technique is highly advantageous involving the natural processes of plants viz., translocation, evapotranspiration, and bioaccumulation, thus degrading contaminants slowly. In particular, nanophytoremediation is a rapid green alternative as it reduces the ancillary impacts of the environment such as green gas emissions, waste generation, and natural resource consumption to the present scenario as there is a great potential of nanoparticles from plants which can be synthesized. Nanophytoremediation is a current methodology for remediation of pollutants, contaminants by using synthesized nanoparticles from plants. In this, the use of different strategies enhances the selective uptake capabilities of plants. The metal elements in excess are affecting the physiological processes in plants; thus, it is necessary to apply nanophytoremediation technology through transgenic plants. In this review paper, we focused on plant species, which can be used as metal tolerant, hyperaccumulators. Due to the insurmountable pressure of a sustainable cleaner environment, bioremediation can be concurrent with nanoparticles for efficient and effective sustainable measures.

Phytoremediation of Heavy Metals by Azolla filiculoides Lam. From Fly Ash Polluted Water Bodies

Article

Full-text available

Jun 2023
WATER AIR SOIL POLL

Percolation of toxic metals existing in fly ash is the prime source of subterranean water contamination in the locale areas near industrial units. In this regard, a field survey was done in the vicinity of Rosa Thermal Power Plant situated in the Shahjahanpur district of Uttar Pradesh, India to examine the natural vegetation particularly aquatic ferns growing naturally in fly ash (FA) contaminated water bodies. It was observed that four aquatic ferns namely Marsilea minuta, Salvinia molesta, Ceratopteris thalictroides, and Azolla filiculoides were growing in the target site in which Azolla biomass has been found enduring and flourishing dominantly near the banks of Garrah River adjoining to the thermal power plant. The result of physicochemical studies of FA polluted water bodies revealed that the concentration of Cd, Cr, Pb, Al, Ni, Si, Mn, and Cu were 42.3, 41.1, 40.1, 4615, 204, 5600, 70 and 58.6 (μg/g) which are significantly high in comparison to the control (reference) site in which Cd, Cr, Pb, Al and Si are below detection limit and Ni, Mn, and Cu were 23.8, 45.8 and 25.4 (μg/g) respectively. Similarly, the metal content of collected Azolla filiculoides was significantly higher than the control site. Metal content (μg/g) in Azolla was found according to following pattern: Fe (61400) ˃ Si (9400) ˃ Cr (7900) ˃ Ni (6100) ˃ Cu (5600) ˃ Pb (4900) ˃ Zn (4600) ˃ Al (3800) > Mn (3200) > Cd (2700) > B (1100). The total chlorophyll was heavily decreased by 58.33 (%) in FA contaminated site in comparison to the control site. The result of antioxidant enzymes like MDA, SOD, and GPX was found to increase by 73.38 (%), 47.56 (%), and 80.75 (%) respectively in Azolla biomass growing in polluted water bodies due to the generation of oxidative damage by free radicals. However, the plant was not showing any visual phytotoxic symptoms. Therefore, it indicates that the Azolla filiculoides has the capability to withstand FA-induced metal toxicity and it may prove an ideal candidate to detoxify FA-contaminated water bodies. Graphical Abstract

Removal of benzotriazole micropollutants using Spirodela polyrhiza (L.) Schleid. And Azolla caroliniana Willd

Article

Jun 2023

Phytoremediation of benzotriazoles (BTR) from waters by floating macrophytes is not well understood, but it seems to have the potential to be used in conjunction with conventional wastewater treatment plants. The effectiveness of removing four compounds from the benzotriazole group by floating plants Spirodela polyrhiza (L.) Schleid. And Azolla caroliniana Willd. From the model solution, was studied. The observed decrease in the concentration of studied compounds was in the range 70.5%-94.5% using S. polyrhiza, and from 88.3% to 96.2% for A. caroliniana. It was determined using chemometric methods that the effectiveness of the phytoremediation process is mainly influenced by three parameters: exposure time to light, pH of the model solution and the mass of plants. Using the design of experiments (DoE) chemometric approach, the optimal conditions for removing BTR were selected: plant weight 2.5 g and 2 g, light exposure 16 h and 10 h, and pH 9 and pH 5 for S. polyrhiza and A. caroliniana, respectively. Studies on the mechanisms of BTR removal have shown that the reduction in concentration is mainly due to the process of plant uptake. Toxicity studies have proved that the tested BTR affected the growth of S. polyrhiza and A. caroliniana and induced changes in the levels of chlorophyllides, chlorophylls as well as carotenoids. More dramatic loss in plant biomass and photosynthetic pigment contents was observed in A. caroliniana cultures exposed to BTR.

Exploring the Effects of Iron Nanoparticles on Plants: Growth, Phytotoxicity, and Defense Mechanisms

Chapter

Jan 2023

Iron (Fe) is an essential micronutrient for all organisms because it plays a significant role in metabolic processes (e.g., photosynthesis, respiration, and DNA synthesis), and many metabolic pathways are activated by Fe. Globally, Fe deficiency is a serious health concern due to the consumption of low-iron diets (or plant-based diets). Fe deficiency in humans induces severe diseases such as anemia. Considering the importance of Fe for the development of both humans and plants, this chapter reports some of the recent advancements in nano-fertilizer for improving crop quality and subsequent human intake to alleviate the Fe deficiency. Furthermore, synthesis methods of Fe-based-NPs, e.g., chemically and bio-synthesis are discussed in details alongside advanced characterization techniques. Exposure of Fe-based nanomaterials via control release systems can enhance crops’ growth and nutritional content. Present chapter indicated that Nano-enabled technologies could be beneficial for reducing the dependence on chemical fertilizers and solving the Fe deficiency problem. The application of Fe-based nano fertilizers can prove to be a sound and sustainable approach to achieve the goal of increasing micronutrient content and crop yield. Fe-based nano fertilizers can bring nutrient-rich crops with economic advantages if the products are environmentally and economically sustainable.KeywordsIron based nanoparticlesPlant healthToxicityDefensive mechanism

Interaction Between Metal Nanoparticles and PGPR on the Plant Growth and Development

Chapter

Jun 2023

Global agricultural production is facing a lot of challenges. The current agricultural practices seems to be incompetent to meet the global food demands. The increasing health and environmental concerns have also put forward the challenge of attaining global food production in a sustainable manner. The synergistic interactions between different nanoparticles (NPs) and Plant Growth Promoting Rhizobacteria (PGPR) have put forward the novel way of improving plant health and increasing its productivity. Different metal and metal oxide NPs like silver, gold, zinc, titanium dioxide, zinc oxide and iron oxide are known to interact with different PGPR in a synergistic manner. These interactions increase the functioning of microbial partner by improving its plant growth promotion traits. The co-inoculation of NPs with their microbial synergist can be utilized to increase the plant health and productivity during plant exposure to different stresses like salinity stress, heat stress, drought stress, and heavy metal stress. The plant-microbe interaction facilitated by NPs activate the plant defense systems, increase the activity of antioxidant enzymes in plants, and trigger the accumulation of protective solutes like proline and glutathione that increase the plant health and productivity during stressful conditions. In addition, this combinatorial approach can also be utilized for bio fortification of plants.KeywordsNanoparticlePGPRRhizosphereNanoparticle-PGPR InteractionsPlant-Microbe Interactions

Aluminum Oxide Nanoparticles: Plant Response, Interaction, Phytotoxicity, and Defense Mechanism

Chapter

Jun 2023

Aluminum, being the most abundant metal on earth, has applications in diverse fields. To utilize the benefits of aluminum completely, aluminum oxide nanoparticles (NPs) are synthesized and administered on plants because they are the connecting link between the environment and human health. The effect of aluminum oxide NPs on a variety of plant species to check their interaction, uptake, and translocation is analyzed in this chapter. Aluminum oxide NPs’ phytotoxicity is determined by their absorption, transport, and accumulation in plants. Interestingly, the administration of aluminum oxide NPs at different concentrations resulted in a significant effect on root elongation, shoot elongation, seed germination, as well as macro and micronutrient uptake. This chapter has mostly addressed nanoparticle interactions in plants, including their absorption, mobilization, and metabolic effects. We also looked into NPs’ potential to protect plants and control stress under a variety of adverse settings. Aluminum oxide NPs’ effects on the four enzymatic antioxidants namely CAT, POD, SOD, and APX are compared, to examine their effect on different plant species. This chapter will assist researchers in comprehending nanotechnology in combination with agriculture, allowing them to build specialized NPs to meet agricultural needs sustainably.KeywordsAluminum oxide nanoparticlesAntioxidant enzymesReactive oxygen species

Elucidation of Synergistic Interaction Among Metal Oxide Nanoparticles and PGPR on the Plant Growth and Development

Chapter

Jun 2023

The use of nanotechnology applications for the improvement of agriculture sectors is increasing day by day. Relative to conventional fertilizers, nano-fertilizers are promptly uptaken by plants and can enhance the plant's growth and development more efficiently. Thus, nanomaterials i.e. nanofibers, nano-fertilizers, and nano-pesticides can remarkably enhance the plants growth and yield production as well as disease resistance with limiting pathogenic attacks. Plant growth-promoting rhizobacteria (PGPR) are deliberated as beneficial soil bacteria which can boost the plants growth attributes in both direct and indirect ways. These bacteria can restrict the harmful impacts of chemical fertilizers as well as toxic compounds released in the soil as a result of industrialization. The inoculation of PGPR can be proved as an efficient technique to enhance the productivity of the agriculture sector with an environmentally friendly approach. The combined application of nanomaterials and PGPR could be a promising way to maintain crop development and productivity. Additionally, various nanomaterials such as titanium, gold, zeolites, carbon, zinc, silver, silica, etc. with PGPR have an auspicious effect on plant development. This book chapter will explore the novel combined strategy of nanotechnology and PGPR to promote crop productivity.KeywordsNanoparticlesPGPRPlant growth stimulationDevelopmentResponse

Physio-anatomical modifications and element allocation pattern in Alternanthera tenella Colla. associated with phytoextraction of chromium

Preprint

Full-text available

Mar 2023

Intensive industrial activities increased the concentration of chromium in the environment especially in the soil and water, which pose serious threat due to its cytotoxic and carcinogenic nature. Phytoremediation has evolved as an eco-friendly, cost-effective alternative for the decontamination of pollutants, and an attempt has been made to reveal the potential of Cr remediation by an invasive plant, Alternanthera tenella Colla in the present study. The morphological, anatomical and physiological modifications of plant tissues in response to 240 µM of K 2 Cr 2 O 7 is studied, with reference to the elemental distribution pattern and bioaccumulation potential. Assessment of growth parameters showed that Cr adversely affects the elongation of root and shoot, leaf area, and dry biomass weight. Cr influence the macro and micro-elemental distribution in plant tissues specially in roots and leaves. Plants exhibited structural modifications like increase in the thickness and diameter of the xylem walls in the root, stem and leaf tissues of Cr treated A. tenella . Presence of cell structural distortions and Cr deposit inclusions in the xylem wall and the inner parenchyma cells were distinct. Cr stress induced the reduction in pigment content and metabolites like proteins and soluble sugars, while proline, phenol and malondialdehyde marked a significant increase. With BCF and TF values greater than 1 and the mechanisms to cope with the metal stress, A. tenella proves to be an ideal candidate for phytoextraction of Cr.

Advancement in mitigating the effects of heavy metal toxicity in wheat

Chapter

Jan 2023

Heavy metals accumulation in wheat has become a severe menace to food security and human health. Proper understanding of the wheat response to metals stress and its management to minimize uptake may assist to enhance yield, grain quality, and growth. This chapter aims to highlight current updates about various mitigation approaches used to minimize metals uptake and phytotoxicity in wheat. Several agronomic and biological approaches have been studied which do hold a promise for obtaining desirable metals reduction in wheat grains. However, the selection of an appropriate method depends on various factors such as soil properties, type of metal, level of contamination, and environmental conditions. Among the available approaches, the use of low metal accumulating or metal-toxicity tolerant wheat varieties is the most efficient and eco-friendly method to ensure food safety and protect human health. Nevertheless, the applicability of this approach at the field level is undoubtedly necessary. This chapter aims to highlight the advancements in various mitigation approaches against heavy metals stress in wheat.

A review on Phytoremediation: Sustainable method for removal of heavy metals

Article

Nov 2022

Heavy metals (HMs) entered in water due to industrial activities like mining, glass, fertilizer, paper, textile, Pharmaceuticals production and others. These HMs in water above threshold level are toxic and affects soil fertility and crop productivity. HMs are biologically magnified in the upper trophic levels and pose risk to animal and human health. Removal of these HMs with growing plants in affected water/soil (phytoremediation) is an ecologically and economically effective method. These plants capable of absorbing, immobilizing, extracting, and degrading HMs. Phytoremediation capacity of the plants can be increase with the application of new researches related to process including biotechnology and genetic engineering. Present review describe the mechanism of phytoremediation, its suitable plants and recent development in the technology to enhance the removal capacity of plants for HMs, along with proper disposal methods of the harvested biomass, to prevent entry of the HMs in the food chain. To reduce the risk of HMs toxicity in water/ soil/crop and low cost biomass disposal, it is necessary to popularise the method with scientific knowledge.

Microbe-assisted phytomanagement of fly ash spoiled sites

Chapter

Jan 2022

Among the largest known environmental pollutants, fly ash generated as by product from combustion of coal is one of them. It is one of the well-known complex anthropogenic substances, whose indecorous dumping turns out to be a huge environmental concern. Due to the presence of some toxic heavy metals and metalloids like Cr, Zn, Mn, Pb, As, etc., fly ash remains unused to quite an extent and its disposal practice still remains a debatable issue. Search for microbial species which ensure heavy metal resistant property and also have potential in plant growth promotion is essential for fly ash management. Microbes have been observed to excrete organic acids, enzymes, siderophores and protons, to increase metal mobilization, and phytoextraction from dumping site of fly ash. The present chapter provides detailed information relating to fly ash with respect to its properties, generation, utilization, problems due to improper disposal, and main concern to microbe assisted fly ash management.

Integrated phytoremediation approaches for abatement of aquatic pollution and element recovery

Chapter

Jan 2022

Globally, the rapid development in industrialization and urbanization is the primary cause of the rising pollution problem. Because of population growth and agricultural reliance, the earth's finite natural freshwater resources will be under severe strain until 2030. The conservation of the environment necessitates a well-thought-out strategy for removing or mitigating the contaminants’ reversible and irreversible effects. The conventional technologies are energy-intensive, had high maintenance and operation costs, provided insufficient treatment, along with the production of ecologically toxic sludge/wastes. Phytoremediation technology has piqued the interest of many academics across the world as an environmentally friendly clean-up option with various advantages over traditional approaches. It can also be used to recover valuable metals and can be used for the production of renewable energy. This chapter will explore the application of integrating phytoremediation of aquatic pollution with energy and element recovery as well as other ecological services. The problems associated with the application of these technologies and future prospects are also comprehensively discussed.

Temporal phytoremediation potential for heavy metals and bacterial abundance in drainage water

Article

Full-text available

May 2022

Drainage water in developing countries has a high abundance of pathogenic bacteria and high levels of toxic and mutagenic pollutants. Remediation of drainage water is important in water-poor counties, especially with the growing need to secure sustainability of safe water resources to fulfill increasing demands for agriculture. Here, we assess the efficiency of macrophyte Pistiastratiotes to remediate a polluted drain in Egypt, rich in macronutrients, heavy metals, and different types of pathogenic and non-pathogenic bacteria. Drainage water was sampled monthly, for a year, to assess seasonal changes in bacterial abundance, water physicochemical properties (transparency, temperature, dissolved oxygen, EC, pH, N, P, and K), and heavy metals contents (Pb, Zn, and Co) in a polluted drain dominated with P.stratiotes. The ability of P.stratiotes to rhizofiltrate the three heavy metals was calculated. The results showed seasonal variations in the plant rhizofiltration potential of Co and Salmonella abundance. The highest values of dissolved oxygen (12.36 mg/L) and macronutrient elements (N and P) were attained in the winter. The counts of total coliform, fecal coliform, fecal streptococci, and in Salmonella spp. were the highest in the summer. P.stratiotes accumulated Pb more than Zn and Co. The highest levels of rhizofiltration were in summer for Pb and Co and in the autumn for Zn. Canonical correspondence analysis (CCA) showed that the variation in the bacterial abundance and plant rhizofiltration potential was strongly and significantly affected by water-dissolved oxygen. Moreover, the rhizofiltration potential of Pb and Co showed a positive correlation with water N. Overall, P.stratiotes could be proposed as a potential biomonitor for heavy metals in polluted water.

Phenanthrene stress response and phytoremediation potential of free-floating fern Azolla filiculoides Lam

Article

May 2022
INT J PHYTOREMEDIAT

In this study, the potential of Azolla filiculoides, a freshwater fern species, on phenanthrene phytoremediation and biodegradation was investigated. Furthermore, the effect of phenanthrene on growth performance, photosynthetic activity and biosynthesis, and accumulation of secondary metabolites of A. filiculodes were evaluated. Plants were grown in a nitrogen-free Hoagland and exposed to different phenanthrene concentrations (0, 1, 5, and 10 mg/L). Exposure to 10 mg/L phenanthrene caused a significant reduction (42%) in Azolla filiculoides growth compared to control on day 14. The photosynthetic pigment content of A. filiculoides treated with 1 and 5 mg/L was almost the same as the control, while 10 mg/L phenanthrene was significantly reduced. In comparison to unplanted controls, the biodegradation percentages obtained from the planted growth medium were found to be 88, 69, and 60%, respectively, for the application of 1, 5, and 10 mg/L phenanthrene. Data on plant growth, photosynthetic pigments, secondary metabolite contents, and biodegradation percentages indicated the tolerance level and the effective phytoremediation potential of A. filiculoides for phenanthrene was <10 mg/L. The results indicated that A. filiculoides is highly effective in phytoremediation of low concentrations of phenanthrene pollution in a short time.

Recent developments in aquatic macrophytes for environmental pollution control: A case study on heavy metal removal from lake water and agricultural return wastewater with the use of duckweed (Lemnacea)

Chapter

Full-text available

Jan 2022

Aquatic macrophytes are a remarkable method among the phytoremediation processes and treatment techniques of sediment, water, and wastewater, which have the potential to accumulate high heavy metal concentrations. They play an important role in wetland technologies as they can bioaccumulate heavy metals with their indirect/direct absorption mechanism. Since macrophytes have the ability to transfer toxic metals found in sediments and water at varying levels from root to shoots, they can provide a sustainable cycle in aquatic ecosystems. Duckweed (Lemnacea) is one of the plants used for this purpose and it is based on the principle of growing plants together with microorganisms in these systems. In this sense, this chapter discusses firstly review the recent developments in aquatic macrophytes for environmental pollution control, then biosorption and bioaccumulation mechanisms of heavy metals by macrophytes, factors affecting bioremediation with macrophytes, defences of aquatic macrophytes to the presence of heavy metals in aquatic environments, benefits using macrophytes as bioindicators in determining, and monitoring water pollution and waste management and disposal. Finally, the removal efficiency of heavy metal pollution in lake waters and agricultural activity return waters carried out in this area with duckweed (Lemna Minor), which is widely found in the lake flora, was evaluated within the scope of a case study. According to results from this study, duckweed (L. Minor) was found an effective and low-cost aqua macrophytes for this region for removing heavy metals from surface water.

Soil Contamination - Threats and Sustainable Solutions

Book

Full-text available

Aug 2021

Soil is a living, active and nonrenewable reserve and a crucial ecosystem component. Soil presents absorbing and emitting capabilities and is susceptible to contamination by a multiplicity of exogenous and endogenous sources. The study of soil resources and environmental problems is a broad, fascinating field that can take numerous dissimilar directions. Today, many anthropogenic ,as well as geogenic activities, are pressing in soil health, generating a strong ecological concern that requires an interdisciplinary approach involving both regulatory organizations and institutions for promptly resolving this situation. Soil contamination is very complex, and it is also often unsafe and harmful to all living species, including human beings specifically. It most frequently occurs from urban development, agricultural practices, military activities, mine tailings, metal industries, industrial accidents, deposits, or the transport of hazardous chemicals, among several other sources. Like pesticides, chlorinated compounds, and nitrogen, certain trace elements such as arsenic, lead, cadmium, copper, mercury, silver, or nickel pollutants can both be naturally present in the soil and be the consequence of human-made activities that nature cannot—or can only very slowly—decompose or degrade. These interventions can fragment, change, or even destroy soil habitats, significantly modifying the biota that lives in the soil. Whereas soil has a marked self-purification capacity, cleaning up contaminated sites is a long and expensive process. Nonetheless, environmental remediation is an important focus of the green economy, and a wide variety of conventional and emerging technologies must rapidly be employed to remove contaminants from polluted sites in order to restore the soil environment and protect the health of living species, including humans. Finally, ensuring long-term management as a final step is mandatory to evaluate the effectiveness of remedial strategies. This single volume comprises fifteen high-quality chapters, organized into two sections, describing several issues related to soil contamination. The first section, Contamination Sources, comprises seven excellent and detailed chapters, starting with an update in the first chapter about the toxicity of heavy metals in several matrices including soil, water, air, and living organisms, presenting this problem as the main cause of environmental deterioration. This is followed by a second chapter providing information about the advantages and disadvantages of using microbial indices for heavy metal–contaminated and restored soils, highlighting the importance of understanding the mechanism(s) of responding to heavy metal stress and the methods available for the microbial diagnosis of heavy metal–contaminated soils. The third chapter presents an overview of the effect of pentachlorophenol pesticide contamination on microbial diversity, enzymatic activities, microbial biomass, and physicochemical soil characteristics, including a description of a bioremediation process. The fourth chapter summarizes the various sources of cadmium present in the environment and its toxic effects on plants and humans. It also includes a description of some bioremediation approaches to mitigate cadmium pollution in the environment. The fifth chapter provides information about how the prolonged use of high doses of fertilizers of IV animal origin, such as swine manure, can result in the accumulation of metals and phosphorus in the soil. These accumulations potentially contaminate both the soil and surface water resources, mainly due to losses from runoff and subsurface leaching. The sixth chapter depicts one of the potential sources of soil contamination in agricultural production worldwide: the application of chemical fertilizers employed in excessive and disproportionate quantities. The chapter also summarizes the evidence regarding the employment of biofertilizers as an eco-friendly alternative for improving soil quality. Lastly, the seventh chapter of this section provides information about the application of fine materials from different rock types, such as basalt, trachyte, and volcanic pyroclastic fragments, in addition to sedimentary rocks like limestone and gneiss, as potential fertilizers on tropical soils from Cameroon. The chapter focuses on strategies for soil acidity management and the employment of this type of material as a potential source of phosphorus. The second section of this book, Remediation Technologies, emphasizes integrated remediation approaches for detecting potentially biohazardous contaminants. The eighth chapter evaluates the phytoremediation potential of two ornamental plants, namely Basella alba and Codiaeum variegatum, in heavy metal–contaminated soils collected from several sites in Nigeria. The study reveals the ability of both plants to remove heavy metals, the heaviest concentration found to be accumulated in the roots rather than the shoots. The ninth chapter reviews the particularities of hexachlorocyclohexane (HCH)-contaminated soils and critically examines the bases and results of the technologies applied, paying special attention to physicochemical remediation processes. The tenth chapter aims to highlight the huge potential of several types of microorganisms being used as an attractive way of removing or remediating pollutants in landfill leachates, emphasizing their cost-effective and environmentally friendly benefits. The eleventh chapter discusses how to take phytoremediation approaches from a proven technology to accepted practice in an urban context. Additionally, it presents an overview of urban soil types following the application of phytoremediation to urban soils, focusing on inorganic and organic pollutants, to provide a frame of reference for the subsequent discussion on the better utilization of phytoremediation. The twelfth chapter aims to highlight the importance of the synergistic association between plants and microbes for the remediation of petroleum hydrocarbons as an effective tool for reclaiming the soil and the environment. The thirteenth chapter offers an interesting overview of the environmental role of nanophytoremediation in the elimination of the bioaccumulation of toxic nanoparticles. This innovative and encouraging technology has gained greater attention due to its current use in research on plants. This chapter describes several plant families that act in the biosynthesis of nanoparticles as well as the physiological process of nanophytoremediation. The fourteenth chapter provides an interesting overview of the role of soil management and conservation in enhancing microbial activity for soil ecological intensification as well as in buffering the soil to neutralize contaminants. The final, fifteenth chapter highlights the employment of green technologies like phytoremediation, biostimulation, and biodegradation for soil sustainable remediation, including information about nanotechnology in the degradation of contaminants. The editors of Soil Contamination - Threats and Sustainable Solutions are enormously grateful to all the contributing scientists for sharing their knowledge XIV V and insights in this interdisciplinary book project. They have made an extensive effort to arrange the information included in every chapter. The publication of this book is of high importance for researchers, scientists, and engineers with expertise in diverse fields of soil science, health, toxicology, policy making, and other disciplines, who can contribute and share their findings in order to take this area of study forward for future investigations.

Role of Plants in Phytoremediation of Industrial Waste

Chapter

Jun 2021

Phytoremediation is an environment friendly and sustainable way of restoration of contaminated land from trace metals, pesticides and other industrial dangerous pollutants. This technique distinguishes a different mechanism for reduction of environmental pollution from industrial waste. The variety of plants grown in contaminated areas has efficiency to develop a metabolism in various parts (leaf, stem, roots) for the phytoremediation of heavy metals and pesticides. The use of transgenic plants promotes the phytoremediation technology for the improvement of remediation in contaminated areas. The concept of using green plants for phytoremediation enhances the potential of soil for restoration and in achieving UN‐SDGs. The traditional methods have various side effects and loopholes. Thus, the chapter provides the techniques used in the application of phytoremediation and sustainable approach for the restoration of contaminated areas. In order to increase the phytoremediation potential, further research is needed in contaminated areas where industrial waste is dumped.

Plants as Source of Essential Oils and Perfumery Applications

Chapter

Jun 2021

Monica BUTNARIU

Essential oils (EOs) are complex liquid mixtures consisting of volatile organic compounds of vegetable origin, with a fragrant, insoluble in water, soluble in organic solvents or fats. EOs are extracted from flowers, leaves, fruits, bark and sometimes from the wood (camphor wood), using organic solvents or by distillation and steam entrainment. Chemically, the EOs is composed of mixtures of terpene hydrocarbons, aromatic hydrocarbons, terpenoids (alcohols, aldehydes, ketones), organic acids, pigments, ethers, esters, etc. One and the same essential oil can contain up to 50 different substances. Of these compounds, the most important are “terpene hydrocarbons” or terpenoid compounds and terpenoids appointed isoprenoids (mono‐, sesqui‐, di‐, ses‐, and triterpenes, monoterpenic alcohols, etc.) and their derivatives. In small quantities they contain classes of aliphatic compounds (alcohols, aldehydes, aliphatic esters, etc.), aromatics, macrocyclics and their derivatives (amines, organic sulfides, heterocyclic compounds, etc.). Among the compounds contained in a relatively large number of EOs can be highlighted: borneol, camphor, camphor, cedrol, eugenol, geraniol, limonene, linalool, menthol and myrcene, etc.

Potential of Azolla caroliniana for the Removal of Pb and Cd from Wastewaters

Article

Full-text available

Jan 2005
INT AGROPHYS

Heavy metals constitute a serious health risk because they accumulate in soils, water and organisms. One of the methods of removing these pollutants from water and soil is the use of plants (phytoremediation). There are many plants (hyperaccumulators) which have the ability to accumulate large amounts of heavy metals. One of them is the aquatic fern Azolla sp., which can bind some substances. The aim of this study was to verify the ability of Azolla caroliniana Willd. (Azollaceae) to fix Pb and Cd from polluted waters. During the experiment, A. caroliniana was grown in water solution enriched in Pb(II) and Cd(II), each at concentrations of 0.1, 0.5 and 1 mg dm-3. The presence of lead and cadmium ions caused an inhibition of A. caroliniana growth by about 30-37 and 24-47%, respectively. After the end of the experiment, the content of the metals tested was determined in the medium and in the biomass (after mineralization). In the water medium, the decrease of Pb(II) amounted to 90% and that of Cd(II) to 22%. In the A. caroliniana tissues, the content of lead was up to 416 mg Pb per kg d.m., and that of cadmium – up to 259 mg Cd per kg d.m.

Comparison of biomass productivity and nitrogen fixing potential of Azolla SPP

Article

Full-text available

Mar 2003
BIOMASS BIOENERG

Study was conducted on six different Azolla species, available in the germplasm collection of NCCUBGA, IARI, New Delhi namely A. filiculoides, A. mexicana, A. microphylla, A. pinnata, A. rubra and A. caroliniana in a polyhouse to assess their growth potential by determining their maximal biomass productivity, doubling time and relative growth rates. Their nitrogen fixing potential was assessed by acetylene reduction assay. Among them Azolla microphylla gave highest biomass production and relative growth rate followed by Azolla caroliniana. Both these had high nitrogenase activity also. Peak nitrogenase activity of these strains was found on 14th day of growth and it declined on further incubation. Azolla microphylla and Azolla rubra were more tolerant to salinity than others. On the other hand Azolla pinnata, which is endemic species found in India, exhibited low biomass production, relative growth rate and lower nitrogenase activity compared to other species. It was unable to sustain growth in saline medium. Under polyhouse conditions, A. microphylla was found to perform better than other cultures in terms of biomass productivity, N fixing ability and salt tolerance. Hence it is taken up for mass production.

Cadmium Tolerance and Hyperaccumulation in a New Zn-Hyperaccumulating Plant Species (Sedum alfredii Hance)

Article

Full-text available

Feb 2004

Sedum alfredii Hance has been identified as a new zinc (Zn) hyperaccumulating plant species. In this study, the effects of cadmium (Cd) supply levels (control, 12.5, 25, 50, 100, 200, 400, 800molCdL–1) on the growth and cadmium accumulation and Zn supply on Cd accumulation in S.alfredii Hance were studied. The results showed that no reduction in shoot and root dry matter yields were noted when the plants were grown at Cd supply levels up to 200molL–1 in nutrient solution. Slight stimulation on shoot growth was noted at relatively low Cd levels (25 to 100molL–1). Cadmium concentrations in leaves and stems increased with increasing Cd supply levels, and reached a maximum of approximately 9000 and 6500mgkg–1 (DW) at 400molCdL–1, respectively. Root Cd concentration increased sharply only at relatively high Cd levels. Cadmium distribution in different parts of the plant was in the order: leaf > stem root. The amount of Cd accumulated in the shoots reached 2.9 and 3.2mg plant–1 at external Cd levels of 200 and 400molL–1, respectively. The shoot/root Cd ratios were greater than 2 and more than 95% of the total Cd taken up by S.alfredii was translocated to the shoots at the external Cd levels 200molL–1. The concentrations of P, Ca, Mg, B, Fe, Mn, Cu, and in the shoots and roots were influenced differentially by Cd treatments. High Zn supply (500molL–1) enhanced Cd concentrations in the leaves and stems at the Cd levels 100molL–1, and root Cd concentration at the Cd levels 50molL–1. These results indicate that S.alfredii has an extraordinary ability to tolerate and hyperaccumulate Cd and this is the first report of the new Cd hyperaccumulator S.alfredii Hance. The finding of Cd/Zn hyperaccumulation in S.alfredii Hance provides an important plant material for understanding the mechanisms of Cd/Zn co-hyperaccumulation and for phytoremediation of the heavy metal contaminated soils.

Comparative assessment of Azolla pinnata and Vallisneria spiralis in Hg removal from G.B. Pant Sagar of Singrauli Industrial region, India

Article

Full-text available

Jan 2009

The aim of the present work was to monitor the Hg pollution in water and sediments of G.B. Pant Sagar located in Singrauli Industrial Region, India and to suggest the efficient aquatic plants for its phytoremediation. The study assessed the comparative potential of a free floating water fern Azolla pinnata and submerged aquatic macrophyte Vallisneria spiralis to purify waters polluted by Hg. Six days laboratory experiments have been conducted to mark the percentage removal of Hg at initial concentration of 0.1, 0.5, 1.0 and 3.0mg L−1. The percentage removal of Hg was higher for A. pinnata (80–94%) than V. spiralis (70–84%). Likewise, the Hg accumulated in dry mass was much higher for A. pinnata and a high correlation (R 2 = 0.91 for A. pinnata and 0.99 for V. spiralis) was obtained between applied Hg doses and accumulated amounts in biomass. A concentration dependent decrease in chlorophyll a, protein, RNA, DNA and nutrients (NO3− and \textPO\text4\text3 - {\text{PO}}_{\text{4}}^{{\text{3 - }}}) uptake was detected in A. pinnata and V. spiralis due to Hg toxicity. The decrease was more prominent in Azolla than Vallisneria. The results recommended the use of A. pinnata and V. spiralis to ameliorate the industrial effluents (thermal power, chlor-alkali and coal mine effluent) contaminated with Hg.

Phytoremediation Potential of Aquatic Macrophyte, Azolla

Article

Full-text available

Mar 2012

Aquatic macrophytes play an important role in the structural and functional aspects of aquatic ecosystems by altering water movement regimes, providing shelter to fish and aquatic invertebrates, serving as a food source, and altering water quality by regulating oxygen balance, nutrient cycles, and accumulating heavy metals. The ability to hyperaccumulate heavy metals makes them interesting research candidates, especially for the treatment of industrial effluents and sewage waste water. The use of aquatic macrophytes, such as Azolla with hyper accumulating ability is known to be an environmentally friendly option to restore polluted aquatic resources. The present review highlights the phytoaccumulation potential of macrophytes with emphasis on utilization of Azolla as a promising candidate for phytoremediation. The impact of uptake of heavy metals on morphology and metabolic processes of Azolla has also been discussed for a better understanding and utilization of this symbiotic association in the field of phytoremediation.

Biodiversity, bioaccumulation and physiological changes in lichens growing in the vicinity of coal-based thermal power plant of Raebareli district, north India

Article

Full-text available

Sep 2010

The lichen diversity assessment carried out around a coal-based thermal power plant indicated the increase in lichen abundance with the increase in distance from power plant in general. The photosynthetic pigments, protein and heavy metals were estimated in Pyxine cocoes (Sw.) Nyl., a common lichen growing around thermal power plant for further inference. Distributions of heavy metals from power plant showed positive correlation with distance for all directions, however western direction has received better dispersion as indicated by the concentration coefficient-R(2). Least significant difference analysis showed that speed of wind and its direction plays a major role in dispersion of heavy metals. Accumulation of Al, Cr, Fe, Pb and Zn in the thallus suppressed the concentrations of pigments like chlorophyll a, chlorophyll b and total chlorophyll, however, enhanced the level of protein. Further, the concentrations of chlorophyll contents in P. cocoes increased with the decreasing the distance from the power plant, while protein, carotenoid and phaeophytisation exhibited significant decrease.

Phytoremediation of Hg Ans Cd from Industrial Effluents Using an Aquatic Free Floating Macrophyte Azolla pinnata

Article

Full-text available

Jul 2008

Prabhat Kumar Rai

The level of heavy metal pollution in Singrauli, an industrial region in India, was assessed and the phytoremediation capacity of a small water fern, Azolla pinnata R.BR (Azollaceae), was observed to purify waters polluted by two heavy metals, i.e., mercury (Hg) and cadmium (Cd) under a microcosm condition. Azolla pinnata is endemic to India and is an abundant and easy-growing free-floating water fern usually found in the rice fields, polluted ponds, and reservoirs of India. The fern was grown in 24 40-L aquariums containing Hg2+ and Cd2+ ions each in concentrations of 0.5, 1.0, and 3.0 mgL(-1) during the course of this study. The study revealed an inhibition of Azolla pinnata growth by 27.0-33.9% with the highest in the presence of Hg (II) ions at 0.5 mgL(-1) in comparison to the control After 13 days of the experiment, metal contents in the solution were decreased up to 70-94%. In the tissues of Azolla pinnata, the concentration of selected heavy metals during investigation was recorded between 310 and 740 mgKg(-1) dry mass, with the highest levelfoundfor Cd (II) treatment at 3.0 mgL(-1) containing a metal solution.

Zinc effects on cadmium accumulation and partitioning in near-isogenic lines of durum wheat that differ in grain cadmium accumulation

Article

Full-text available

Sep 2005

Here, we examined the effectiveness of two approaches for reducing cadmium (Cd) accumulation in durum wheat (Triticum turgidum L. var durum) grain: the application of supplemental zinc (Zn), and the use of cultivars exhibiting reduced grain Cd concentrations. Two durum wheat near-isogenic lines (NIL) that differ in grain Cd accumulation were grown to maturity in solution culture containing a chelating agent to buffer the free activities of Zn and Cd at levels approximating those of field conditions. The low Cd accumulating (L-Cd) isoline had Cd concentrations, in grains and shoot parts, which were 60-70% lower than those of the high Cd accumulating (H-Cd) isoline. Increasing the Zn activities in the nutrient solution from deficient to sufficient levels reduced the concentration of Cd in grains and vegetative shoot parts of both isolines. The results suggest that supplemental Zn reduces Cd tissue concentrations by inhibiting Cd uptake into roots. Cd partitioning patterns between roots and shoots and between spike components suggest that the physiological basis for the low Cd trait is related to the compartmentation or symplasmic translocation of Cd.

Translocation of metals from fly ash amended soil in the plant of Sesbania cannabina L. Ritz: Effect on antioxidants

Article

Full-text available

Jan 2006
CHEMOSPHERE

The plants of Sesbania cannabina Ritz grown on different amendments of fly ash (FA), have shown a high accumulation of metals (Fe, Mn, Zn, Cu, Pb and Ni). The highest accumulation of Fe the and lowest level of Ni were recorded in these plants. The different amendments of fly ash with garden soil (GS) were extracted with DTPA and the levels of metals were found to be decreased with an increase in fly ash application ratio from 10% to 50% FA. The analysis of the results showed an increase in the level of malondialdehyde (MDA) content of the roots for all the exposure periods. The maximum increases of 136% (roots) and 120% (leaves) were observed in MDA content at 100% FA after 30 d of growth of the plant, compared to GS. The level of antioxidants was found to increase for all the exposure periods in the roots of the plants to combat metal stress. At 30 d, the maximum increase of 57% (ascorbic acid) and 78% (free proline) was observed in the roots of the plants grown on 100% and 10% FA, respectively, as compared to their respective GS. At 90 d, a maximum increase of 42% (cysteine) and 117% (NPSH) was recorded in the roots of the plants grown on 25% and 100% FA, respectively, as compared to their respective GS. In leaves, a significant increase in antioxidants i.e. cysteine, NPSH and free proline content was recorded after 30 d, whereas no such trend was observed for the rest of the exposure periods. The chlorophyll and carotenoid contents increased with an increase in the FA amendment ratio from 10% to 50% FA for all the exposure periods as compared to GS. In both roots and leaves, the level of protein content increased in all the amendments and 100% FA at 30 d as compared to GS. Thus, there is a balance in the level of MDA content and level of antioxidants in the plants at 90 d. In view of its tolerance, the plants may be used for phytoremediation of metals from fly ash contaminated sites and suitable species for plantation on fly ash land fills.

Bioavailability of Metals in Fly Ash and Their Bioaccumulation in Naturally Occurring Vegetation: A Pilot Scale Study

Article

Full-text available

May 2006

A pilot scale study was conducted to find out the different forms of metals if fly ash (FA) and bioaccumulation of these metals in the naturally growing vegetation on FA dumps. The total, acid extractable, bioavailable and water soluble fraction of metals of Fe, Cu, Mn, Zn, Ni, Co and Pb, and their bioaccumulation coefficients (BAC) on naturally growing vegetation were determined. FA samples had a neutral pH, low electrical conductivity, low organic C and trace amounts of N and P. The relative abundance of total metals in FA were found in the order Fe >Mn >Zn >Ni >Co>Cu. The concentration of bioavailable (DTPA) metals depend on the type and nature of coal used in thermal power stations. In the water the extract solution, only Fe and Zn were found above detection limits. After one year only four species of naturally occurring herbaceous vegetation were found growing and Cynodon dactylon (grass) covered almost entire surface of the FA. Iron accumulated to the greatest extent in vegetation followed by Mn, Zn, Cu, Pb, Ni and Co. The sequence of BAC for different metals were Fe (202)>Mn(90)>Zn (63)>Pb(49)>Ni(41)>Cu(24). The experimental study revealed that Cynodon grass could be used for remediation of fly ash without any amendments, as this grass species act as metal excluder type.

Principles of Plant Nutrition

Book

Jan 2001

This is the 5th edition of a well-established book Principles of Plant Nutrition which was first published in 1978. The same format is maintained as in previous editions with the primary aim of the authors to consider major processes in soils and plants that are of relevance to plant nutrition.This new edition gives an up-to-date account of the scientific advances of the subject by making reference to about 2000 publications. An outstanding feature of the book, which distinguishes it from others, is its wide approach encompassing not only basic nutrition and physiology, but also practical aspects of plant nutrition involving fertilizer usage and crop production of direct importance to human nutrition. Recognizing the international readership of the book, the authors, as in previous editions, have attempted to write in a clear concise style of English for the benefit of the many readers for whom English is not their mother tongue. The book will be of use to undergraduates and postgraduates in Agriculture, Horticulture, Forestry and Ecology as well as those researching in Plant Nutrition.

Arsenic hazards in coal fly ash and its fate in Indian scenario

Article

Apr 2011
RESOUR CONSERV RECY

A comparison of metallic contents in lichen Pyxine subcinerea, its substratum and soil

Article

May 2012

Chromium, copper, cadmium, lead, nickel, iron and zinc contents of a lichen species (Pyxine subcinerea Stirton) and mango bark collected from 12 sites in Haridwar city (Uttarakhand) were compared with soil, sampled from beneath the tree from which lichens were collected. The metal contents in lichen, bark and soil ranged from 1,573 to 18,793, 256 to 590 and 684 to 801 μg g−1, respectively. This clearly indicates that lichens accumulated higher amounts of metal compared to bark or soil. Statistical analysis revealed that metal concentration in lichens did not show significant linear correlation with the bark or soil. Pearsons correlation coefficients revealed negative correlation of Pb (r = −0.2245) and Ni (r = −0.0480) content between lichen and soil, which indicate direct atmospheric input of metals from ambient environment. Quantification and comparison of elemental concentration in lichens, its substratum and soil can provide valuable information about air quality in the collection area.

Naturally growing Saccharum munja L. on the fly ash lagoons: A potential ecological engineer for the revegetation and stabilization

Article

Mar 2012
ECOL ENG

Increasing areas of coal fly ash (FA) deposit pose a serious concern for its safe disposal to maintain the environment quality. Several thousand hectares of land have been occupied for the storage of FA all over the world. FA deposits cause serious environmental pollution through wind erosion and ground water contamination through leaching process. Naturally growing Saccharum munja on the derelict FA lagoons of NTPC Unchahar, India was identified as a native perennial grass in the rehabilitation process. We tested its ecological suitability for the effective restoration of FA lagoons in terms of their abundance and stabilization. The FA contains alkaline pH, and low organic C coupled with toxic metals i.e. Fe, Cd, Cr, Cu, Mn, Ni, Pb and Zn. The concentrations of these metals in different parts of the plant fall in the average range of plants and were found within toxic limits. Natural colonization of S. munja predominate in the areas of FA deposits with fast growth and high biomass which is used by local people for making ropes, baskets, mats, huts, etc. to support their livelihood. These results suggest that S. munja would be potentially useful to rehabilitate the FA dumps more efficiently if it is introduced properly on fresh lagoons to convert barren FA deposits into ecologically and socio-economically productive habitats without any inputs or maintenance.

Phytoaccumulation of cadmium through Azolla from aqueous solution

Article

Nov 2011
ECOL ENG

Azolla, which is an aquatic fern, has proved to be effective in the uptake and accumulation of metals from polluted waters. Azolla spp., namely A. microphylla cv. MH3 and A. caroliniana Willd, were chosen as model plants so that Cd(II) could be accumulated from aqueous solution. An increase in uptake time and the concentration of Cd(II) in aqueous solution resulted in more Cd(II) accumulation in both species. Modified Michaelis–Menten equation was employed to describe the concentration-dependent kinetics of Cd(II) uptake through the roots of A. microphylla cv. MH3, and the values of Km and Vmax were found to be 0.23mg/L and 16.49μg/(g.f.wt.h), respectively. Cd(II) uptake by A. microphylla cv. MH3 occurs partly through Ca(II) channels and has the potential to be mediated by Zn(II) transporters.

Is Vigna radiata suitable for the revegetation of fly ash landfills?

Article

Dec 2011
ECOL ENG

The present article briefly describes the concerns regarding the suitability of Vigna radiata L. for the revegetation of fly ash landfills.

Phytoaccumulation of Chromium, Uranium and Plutonium in Plant Systems

Article

May 1998

Phytoremediation is an integrated multidisciplinary approach to the cleanup of contaminated soils, which combines the disciplines of plant physiology, soil chemistry, and soil microbiology. Metal hyperaccumulator plants are attracting increasing attention because of their potential application in decontamination of metal-polluted soils. Traditional engineering technologies may be too expensive for the remediation of most sites. Removal of metals from these soils using accumulator plants is the goal of phytoremediation. The emphasis of this review has been placed on chromium (Cr), plutonium (Pu), and uranium (U). With the exception of Cr, these metals and their decay products exhibit two problems, specifically, radiation dose hazards and their chemical toxicity. The radiation hazard introduces the need for special precautions in reclamation beyond that associated with non-radioactive metals. The uptake of beneficial metals by plants occurs predominantly by way of channels, pores, and transporters in the root plasma membrane. Plants characteristically exhibit a remarkable capacity to absorb what they need and exclude what they don`t need. But most vascular plants absorb toxic and heavy metals through their roots to some extent, though to varying degrees, from negligible to substantial. Sometimes absorption occurs because of the chemical similarity between beneficial and toxic metals. Some plants utilize exclusion mechanisms, where there is a reduced uptake by the roots or a restricted transport of the metal from root to shoot. At the other extreme, hyperaccumulator plants absorb and concentrate metals in both roots and shoots. Some plant species endemic to metalliferous soils accumulate metals in percent concentrations in the leaf dry matter.

Chemical properties of metals and the process of bioaccumulation in terrestrial plants

Chapter

Jan 1993

Impact of Fly Ash Incorporation in Soil Systems

Article

Feb 2010
AGR ECOSYST ENVIRON

Fly ash (FA)—a coal combustion residue of thermal power plants has been regarded as a problematic solid waste all over the world. The conventional disposal methods for FA lead to degradation and contamination of the arable land. However, several studies proposed that FA can be used as a soil-additive that may improve physical, chemical and biological properties of the degraded soils and is a source of readily available plant micro- and macro-nutrients. Numerous studies revealed that the lower FA incorporation in soil modifies the physico-chemical, biological and nutritional quality of the soil. However, the higher dosage of FA incorporation results in heavy metal pollution and hinders the microbial activity. Practical value of FA in agriculture as an “eco-friendly and economic” fertilizer or soil amendments can be established after repeated field experiments for each type of soil to confirm its quality and safety. Integrated Organic/Biotechnological approaches should be applied for the reducing toxicity of FA contaminated site near thermal power plants. Overall, study reveals that FA could be effectively used in the barren or sterile soil for improving quality and enhancing fertility. The purpose of this paper is to explore the possibility of FA addition into degraded soils for improving nutritional and physico-chemical properties.

Arsenic accumulation by the aquatic fern Azolla: Comparison of arsenate uptake, speciation and efflux by A. caroliniana and A. filiculoides

Article

Dec 2008

This study investigates As accumulation and tolerance of the aquatic fern Azolla. Fifty strains of Azolla showed a large variation in As accumulation. The highest- and lowest-accumulating ferns among the 50 strains were chosen for further investigations. Azolla caroliniana accumulated two times more As than Azolla filiculoides owing to a higher influx velocity for arsenate. A. filiculoides was more resistant to external arsenate due to a lower uptake. Both strains showed a similar degree of tolerance to internal As. Arsenate and arsenite were the dominant As species in both Azolla strains, with methlyated As species accounting for <5% of the total As. A. filiculoides had a higher proportion of arsenite than A. caroliniana. Both strains effluxed more arsenate than arsenite, and the amount of As efflux was proportional to the amount of As accumulation. The potential of growing Azolla in paddy fields to reduce As transfer from soil and water to rice should be further evaluated.

Phytofiltration of cadmium from water by Limnocharis flava (L.) Buchenau grown in free-floating culture system

Article

Jun 2009

The Indian perspective of utilizing fly ash in phytoremediation, phytomanagement and biomass production

Article

Jul 2009
J ENVIRON MANAGE

Coal-based power generation is a principal source of electricity in India and many other countries. About 15-30% of the total amount of residue generated during coal combustion is fly ash (FA). FA is generally alkaline in nature and contains many toxic metals like Cr, Pb, Hg, As and Cd along with many essential elements like S, B, Ca, Na, Fe, Zn, Mn and P. Dumped FA contaminates the biosphere by mobilization of its fine particles and hazardous metals. Despite the negative environmental impact of FA, coal continues to be a major source of power production in India and therefore FA disposal is a major environmental issue. To overcome this problem, FA dumping sites have been started as a potential resource for biomass production of tree species. Phytoremediation is a strategy that uses plants to degrade, stabilize, and remove contaminants from soils, water and waste FA. Phytomanagement of FA is based on the plants' root systems, high biomass, woody nature, native nature, and resistance to pH, salinity, and toxic metals. Recently Indian researchers mostly from the National Botanical Research Institute have been working on phytoremediation and revegetation of FA dykes, inoculation of bacterial strains for reducing FA stress and biomass production from FA dykes. Many international researchers have worked on reclamation, revegetation and utilization of FA. FA utilization saves resources, mainly land (topsoil), water, coal, limestone and chemical fertilizer. Safe utilization of FA is a major concern around the world and regulatory bodies are enforcing stringent rules for the proper management of FA. This article summarizes various viable avenues in India for FA utilization and environmental management.

Mutagenicity and genotoxicity of coal fly ash water leachate

Article

Nov 2008
ECOTOX ENVIRON SAFE

Fly ash is a by-product of coal-fired electricity generation plants. The prevalent practice of disposal is as slurry of ash and water to storage or ash ponds located near power stations. This has lain to waste thousands of hectares of land all over the world. Since leaching is often the cause of off-site contamination and pathway of introduction into the human environment, a study on the genotoxic effects of fly ash leachate is essential. Leachate prepared from the fly ash sample was analyzed for metal content, and tested for mutagenicity and genotoxicity. Analyses of metals show predominance of the metals-sodium, silicon, potassium, calcium, magnesium, iron, manganese, zinc, and sulphate. The Ames Salmonella mutagenicity assay, a short-term bacterial reverse mutation assay, was conducted on two-tester strains of Salmonella typhimurium strains TA97a and TA102. For genotoxicity, the alkaline version of comet assay on fly ash leachate was carried in vitro on human blood cells and in vivo on Nicotiana plants. The leachate was directly mutagenic and induced significant (P<0.05) concentration-dependent increases in DNA damage in whole blood cells, lymphocytes, and in Nicotiana plants. The comet parameters show increases in tail DNA percentage (%), tail length (mum), and olive tail moment (arbitrary units). Our results indicate that leachate from fly ash dumpsites has the genotoxic potential and may lead to adverse effects on vegetation and on the health of exposed human populations.

The ability of Azolla caroliniana to remove heavy metals (Hg(II), Cr(III), Cr(VI)) from municipal waste water

Article

May 2004
CHEMOSPHERE

The aim of this paper was to investigate the capacity of a small water fern, Azolla caroliniana Willd. (Azollaceae), to purify waters polluted by Hg and Cr. Many plants are capable of accumulating heavy metals (called hyperaccumulators) and one of them is the water fern A. caroliniana. During 12 days of the experiment the fern was grown on the nutrient solution containing Hg2+, Cr3+ and CrO4(2-) ions, each in a concentration 0.1, 0.5 and 1.0 mg dm(-3). The presence of these ions caused a 20-31% inhibition of A. caroliniana growth, the highest in the presence of Hg(II) ions, in comparison to the control. After day 12 of the experiment, metal contents the solution decreased to 0-0.25 mg dm(-3), and this decrease comprised between 74 (Cr3+ 1.0 mg dm(-3) treatment) and 100% (CrO4(2-) 0.1 mg dm(-3) treatment). The fern took a lesser quantity of the metals from 0.1 mg dm(-3) treatments compared to 0.5 and 1.0 mg dm(-3) treatments. In the A. caroliniana tissues the concentration of heavy metals under investigation ranged from 71 to 964 mg kg(-1) dm; the highest level being found for Cr(III) containing nutrient solution.

Lead Accumulation in the Aquatic Fern Azolla filiculoides

Article

Jul 2004
PLANT PHYSIOL BIOCH

In this study, we characterized lead (Pb2+) accumulation and storage by the aquatic fern Azolla filiculoides. Lead precipitates were detected in the vacuoles of mesophyll cells of Azolla plants cultured for 6 d in rich growth medium containing 20 mg l(-1) Pb2+. Energy dispersive spectroscopy (EDS) analysis of the relative element content of leaves collected from these plants revealed a 100% increase in the levels of P, S, Na and Ca and a 40% decrease in Mg and Cl compared to the untreated plants. Both Azolla whole plants and isolated apoplasts were incubated for 6 d in 20 mg l(-1) Pb2+. Lead content in the whole plant composed 0.37%, 2.3% and 1.8% of the dry weight after 2, 4 and 6 d of growth, respectively, while the isolated Azolla apoplast contained 0.125%, 1.22% and 1.4% Pb2+, respectively. Lead content in Azolla whole plant increase by 200%, 100% and 22% after 2, 4 and 6 d of growth, respectively, when compared to Azolla apoplast. Dark, electron dense deposits of lead were observed in light and transmission electron microscope in leaf cells treated with lead. All the observed lead deposits were localized in vacuoles while larger lead deposits were found in mature leaves than in young leaves. No lead deposits were found in cells of the cyanobiont Anabaena when the plants were exposed to similar conditions. Activity and content of V-H+-ATPase were studied in Azolla plants grown in the presence of 20, 40 and 80 mg l(-1) of lead for a period of 4 d. Activity of V-H+-ATPase was increased by 190%, 210% and 220%, respectively, but the content of V-H+-ATPase was reduced by all lead concentrations.

Arsenic Speciation and Distribution in an Arsenic Hyperaccumulating Plant

Article

Jan 2003
SCI TOTAL ENVIRON

Arsenic-contaminated soil is one of the major arsenic sources for drinking water. Phytoremediation, an emerging, plant-based technology for the removal of toxic contaminants from soil and water, has been receiving renewed attention. Although a number of plants have been identified as hyperaccumulators for the phytoextraction of a variety of metals, and some have been used in field applications, no hyperaccumulator for arsenic had been previously reported until the recent discovery of Brake fern (Pteris vittata), which can hyperaccumulate arsenic from soils. This finding may open a door for phytoremediation of arsenic-contaminated soils. Speciation and distribution of arsenic in the plant can provide important information helpful to understanding the mechanisms for arsenic accumulation, translocation, and transformation. In this study, plant samples after 20 weeks of growth in an arsenic-contaminated soil were used for arsenic speciation and distribution study. A mixture of methanol/water (1:1) was used to extract arsenic compounds from the plant tissue. Recoveries of 85 to 100% were obtained for most parts of the plant (rhizomes, fiddle heads, young fronds and old fronds) except for roots, for which extraction efficiency was approximately 60%. The results of this study demonstrate the ability of Brake fern as an arsenic hyperaccumulator. It transfers arsenic rapidly from soil to aboveground biomass with only minimal arsenic concentration in the roots. The arsenic is found to be predominantly as inorganic species; and it was hypothesized that the plant uptakes arsenic as arsenate [As(V)I and arsenate was converted to arsenite [As(III)] within the plant. The mechanisms of arsenic uptake, translocation, and transformation by this plant are not known and are the objectives of our on-going research.

Bioaccumulation and translocation of metals in the natural vegetation growing on fly ash lagoons: A field study from Santaldih thermal power plant, West Bengal, India

Article

Jan 2008
ENVIRON MONIT ASSESS

A field study was conducted in the fly ash lagoons of Santandih Thermal Power Plant located in West Bengal (India) to find out total, EDTA and DTPA extractable metals in fly ash and their bioaccumulation in root and shoot portion of the naturally growing vegetation. Fly ash sample has alkaline pH and low conductivity. The concentration of total Cu, Zn, Pb and Ni were found higher than weathered fly ash and natural soil, where as Co, Cd and Cr were found traces. Five dominant vegetation namely, Typha latifolia, Fimbristylis dichotoma, Amaranthus defluxes, Saccharum spontaenum and Cynodon dactylon were collected in the winter months (November-December). Bioaccumulation of metals in root and shoot portions were found varied significantly among the species, but all concentration were found within toxic limits. Correlation between total, DTPA and EDTA extractable metals viz. root and shoot metals concentration were studied. Translocation factor (TF) for Cu, Zn and Ni were found less than unity, indicates that these metals are immobilized in the root part of the plants. Metals like Mn have TF greater than unity. The study infers that natural vegetation removed Mn by phytoextraction mechanisms (TF > 1), while other metals like Zn, Cu, Pb and Ni were removed by rhizofiltration mechanisms (TF < 1). The field study revealed that T. latifolia and S. spontaenum plants could be used for bioremediation of fly ash lagoon.

Crop and food chain effects of toxic elements in sludges and effluents

Jan 1973
129-141

R L Chaney

Chaney, R.L., 1973. Crop and food chain effects of toxic elements in sludges and effluents. In: Proceedings of the Joint Conference on Recycling Municipal Sludge and Effluents on Land. National Association of State Universities and Land-Grant Colleges, Washington, DC, pp. 129-141.

Principles of Plant Nutrition The Netherlands The Indian perspective of utilizing fly ash in phytoremediation, phytomanagement and biomass production

Jan 2001
2943-2958

K Mengel
E A Kirkby

Mengel, K., Kirkby, E.A., 2001. Principles of Plant Nutrition, fifth ed. Kluwer Academic Publishers, Dordrecht, The Netherlands, p. 849. Pandey, V.C., Abhilash, P.C., Singh, N., 2009. The Indian perspective of utilizing fly ash in phytoremediation, phytomanagement and biomass production. J. Environ. Manage. 90, 2943–2958.

Human and Ecological Risk Assessment of Coal Combustion Wastes (draft)

Jan 2007

Us Epa

US EPA, 2007. Human and Ecological Risk Assessment of Coal Combustion Wastes (draft).

A comparison of heavy metals in lichen (Pyxine subcinerea), mango bark and soil

Jan 2012

V Shukla
D K Patel
D K Upreti
M Yunus
S Prasad

Shukla, V., Patel, D.K., Upreti, D.K., Yunus, M., Prasad, S., 2012. A comparison of heavy metals in lichen (Pyxine subcinerea), mango bark and soil. Int. J. Environ. Sci. Technol. http://dx.doi.org/10.1007/s13762-012-0075-1.

Phytoremediation of heavy metals from fly ash pond by Azolla caroliniana

Abstract

No full-text available

Recommendations

Phytoremediation efficiency of Eichhornia crassipes in fly ash pond