No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Phytoremediation: an environmentally sound technology for pollution prevention, control and remediation in developing countries
Abstract
The problem of environmental pollution has assumed an unprecedented proportion in many parts of the world especially in Nigeria and its Niger-Delta region in particular. This region is bedeviled with this problem perhaps owing to interplay of demographic and socio-economic forces coupled with the various activities that revolve round the exploration for and exploitation of large deposit of crude oil discovered there. Many methods and processes of preventing, removing and or correcting the negative effects of pollutants released into the environments exist but their application in this country for this purpose has either been poorly implemented or not at all, a situation that is worsening owing probably to claims of lack of virile regulatory bodies and overwhelming dependence of government on crude oil for income. Studies have shown that the livelihood of local inhabitants largely depend on renewable natural resources which is environment dependent, thus, it is imperative that the environment should be sustainably managed in order to continue serving this function through comparatively cheaper means, one of which phytoremediation is. The objective of this review is to discuss phytoremediation studies using in-situ techniques and their potentials as a remediation technique that utilizes the age-long inherent abilities of living plants to remove pollutants from the environment but which is yet to become a commercially available technology in many parts of the world including Nigeria.
... For instance, Cr(VI) can be oxidized to form Cr(III), a less mobile and hazardous form [70]. Nevertheless, phytostabilization is not a long-lasting solution because the heavy metals persist in the soil [161], only their mobility is reduced [2]. Utilization of plants to decrease the mobility and bioavailability of contaminants in the environment, hence avoiding their migration into groundwater and the food chain [179] and sequestering the pollutants in or on cell wall lignins (lignification), absorption of pollutants by soil humus via plant or microbial enzymes (humification), or other methods by which the pollutant is sequestered in the soil, for example, through binding to organic matter [180]. ...
... Because of environmental restrictors present at locations such as weed competition, restricted plant evolution in a contaminated environment, the appearance of plant infections, and other abiotic/biotic stressors, the microbial augmented rhizoremediation process is substantially slower than ex-situ operations [178]. The release of exudates/enzymes into the root zone (rhizosphere) stimulates microbial and fungal breakdown in plant-assisted bioremediation [179]. ...
Contamination by heavy metals is a significant issue worldwide. In recent decades, soil heavy metals pollutants in China had adverse impacts on soil quality and threatened food security and human health. Anthropogenic inputs mainly generate heavy metal contamination in China. In this review, the approaches were used in these investigations, focusing on geochemical strategies and metal isotope methods, particularly useful for determining the pathway of mining and smelting derived pollution in the soil. Our findings indicate that heavy metal distribution substantially impacts topsoils around mining and smelting sites, which release massive amounts of heavy metals into the environment. Furthermore, heavy metal contamination and related hazards posed by Pb, Cd, As, and Hg are more severe to plants, soil organisms, and humans. It’s worth observing that kids are particularly vulnerable to Pb toxicity. And this review also provides novel approaches to control and reduce the impacts of heavy metal pollution. Hydrometallurgy offers a potential method for extracting metals and removing potentially harmful heavy metals from waste to reduce pollution. However, environmentally friendly remediation of contaminated sites is a significant challenge. This paper also evaluates current technological advancements in the remediation of polluted soil, such as stabilization/solidification, natural attenuation, electrokinetic remediation, soil washing, and phytoremediation. The ability of biological approaches, especially phytoremediation, is cost-effective and favorable to the environment.
... Phytoremediation is fundamentally plant-based (aquatic, semi aquatic and terrestrial) and related associated enzymes, microorganism and water consumption, uptake, remove, retain, transform, degrade or immobilize contamination (organic and/or inorganic) with different origin, from soil, sediment and aquatic media or atmosphere [10,11,12,13,14,15]. Phytoremediation is also known for green remediation, agricultural remediation and vegetative remediation [16]. Nurul et al., was conducted phytoremediation study to examine the capacity of five aquatic plants, namely Salvinia molesta, Eichhornia crassipes, Pistia stratiotes, Centella asiatica, and Ipomoea aquatica, and also to remove three contaminants from aquaculture effluent, namely phosphate, total suspended solids (TSS), and ammoniacal nitrogen (NH3-N). ...
Water is the most required element next to air for terrestrial living being. Though the water is everywhere but no direct use is possible as the fresh water is getting contaminated through various human activities. The conventional treatment methods using activated sludge process, attached growth systems such as trickling filters, rotating biological contactors, aerated lagoons and stabilization ponds are normally practiced in many places with each one having its own merits and demerits depending on space availability, energy requirements etc. An alternative solution called phytoremediation method can save energy requirements to the great extent but space required will be more and it can be used advantageously where space is not a constraint. This method involves using plants to absorb and metabolize pollutants found in wastewater, including nutrients such as nitrogen and phosphorus, heavy metals and other organic and inorganic contaminants. In this study, sewage is passed through a bed of plants, which takes up nutrients and contaminants while releasing oxygen during their photosynthesis process. This promotes the growth of beneficial bacteria that further break down pollutants. In the present work, Spider lily (Hymenocallis littoralis) and Heliconia (Heliconia psittacorum) are two species of tropical plants used in constructed wetlands and that have shown potential in the treatment of sewage. Conducted the performance studies on both plants separately. The efficiency achieved with spider lily plants Heliconia plants are 87.2% and 79.6% in BOD removal respectively. These systems are also relatively low-cost and require minimal maintenance, making them a viable option for wastewater treatment in areas where conventional treatment systems may be too expensive or impractical.
... Certain plants can stabilize the contaminants and therefore restrict them to the polluted sites only (Singh 2012). Phytostabilization is used to decrease the movement and bioavailability of contaminants in the environment, therefore avoiding their passage to groundwater or their entry into the food chain (Erakhrumen 2007). Plants can reduce the mobility of heavy metals in contaminated land through adsorption by roots, complexation, or metal valence reduction in the rhizosphere precipitation (Wuana and Okieimen 2011). ...
... The use of specific plants for stabilising pollutants in polluted soils is known as phyto stabilization or phytoimmobilization (Singh, 2012). By reducing the mobility and bioavailability of contaminants in the environment, this approach stops them from moving into groundwater or the food chain (Erakhrumen and Agbontalor 2007). The process of phytostabilization reduces the buildup of heavy metals in biota and their leakage into groundwater. ...
Environmental collapse is a universal issue in today's fast-paced culture. Polluted environments brought on by anthropogenic activity (mine, oil, agricultural spray, and fertilisation) are harmful to both humans and the biosphere. Urban soil and water contamination from fast urbanization is increasingly acting as a sink for a range of contaminants, such as heavy metals, pesticides, petroleum waste, radioactive molecules, etc. A low-cost, very effective way to extract or remove contaminants from the environment is through phytoremediation. Decontaminating heavy metal-contaminated locations using phytoremediation may be an effective approach, especially if the biomass created during the procedure can be used to generate bioenergy at a reasonable cost. The present study discusses a number of phytoremediation approaches, including phytodegradation, phytoextraction, phytostimulation, phytostabilization, phytofiltration, phytovolatilization, etc., that can be used to treat places where metals and other inorganic chemicals are present. In an effort to remove, detoxify, or immobilise environmental toxins in a growth matrix, a new method called phytoremediation uses the natural, biological, chemical, or physical activities of plants. As a result, this strategy is a cutting-edge instrument that has a great chance of decontaminating soil and water. In order to ensure the sustainability of current generations and lessen pollution, phytoremediation is a viable technology.
... However, it also has some limitations, as it may take several years to remediate a polluted site; it can be time-consuming, making this approach inappropriate for restoring areas that may constitute a severe risk to the ecosystem and human beings [33,40]. Another noteworthy limitation of this technique is the essential contact between the root zone of plants and contaminants [39,[56][57][58]. Therefore, the critical role played by roots in phytoremediation has usually limited its appliance to shallow, contaminated soils, with the only exemption being the utilization of some trees to reach zones in the range of one to several meters [59]. ...
Water and soil polluted by heavy metals (HMs) are the primary problem due to rapidly increasing urbanization and industrialization. For the treatment of polluted soil, phytoremediation turns into a cost-effective and eco-friendly technique. The current research aimed to examine the load of pollution, specifically HMs, in sediment and wastewater (WW) of the GadoonAmazai Industrial Estate (GAIE), Pakistan and compare the ability of native grass species Cynodon dactylon and Digiteria sanguinalis for the phytoaccumulation of HMs. The industrially polluted soil was analysed for HMs using atomic absorption spectrophotometry (AAS) and compared with healthy soil (irrigated by freshwater), which served as a control. The HM accumulation was considerably higher in the soil irrigated with WW than in control soil samples. The most substantial metal pollutant was manganese (Mn), which accumulated up to 2491.7 mg/kg in the WW irrigated soil. For assessing the bioremoval efficiency of grass species, pot experimentation was performed for 90 days. Soil samples and grasses were collected from the pots to examine the HM removal efficiency. A significant reduction was noted in physicochemical characteristics of the soil, such as electrical conductivity, total organic matter, phosphorus, potassium, and saturation. The grasses removed up to 59.0% of the Cu and 59.9% of Mn from the soil. The highest bioconcentration factor (BCF) and translocation factor (TF) of Cu were observed for D. sanguinalis. While the highest BCF and TF of Mn were obtained for C. dactylon. The research showed that the grass significantly (p ≤ 0.05) reduced HM in soil samples. Moreover, the selected grasses found a higher capability to accumulate HM in the roots than in the shoot. The maximum Cu removal was obtained by D. sanguinalis and Mn by C. dactylon. The research study concluded that phytoremediation using D. sanguinalis and C. dactylon is an eco-friendly and cost-effective method that can be utilized for soil remediation.
... One of the efforts to improve the quality of rice fields contaminated with heavy metals is phytoremediation (Yuan et al. 2019;Hussain et al. 2021a). Phytoremediation is regarded as a contaminant removal method, particularly for heavy metals, that is simple, sustainable, and economical (Erakhrumen and Agbontalor 2007;Sharma and Pandey 2014). Several studies have reported employing hyperaccumulators in phytoremediation applications (Zhao et al. 2003;Liu et al. 2009;Rascio and Navari-Izzo 2011;Zhong et al. 2019;Raza et al. 2020). ...
Hasanah NAU, Purwanto E, Harsono P, Samanhudi, Sakya AT. 2023. Morphological responses of six sorghum varieties on cadmium-contaminated soil. Biodiversitas 24: 3903-3915. Six sorghum varieties were planted on cadmium-contaminated soil and characterized from April to July 2020 at a rice field in Balecatur Gamping, Yogyakarta. The objectives of this experiment were to characterize themorphological responses of six sorghum varieties and select a variety with a high biomass and Cd uptake fora potential phytoremediator. This experiment used six sorghum varieties, namely Super-1, Samurai-1, Suri-3, Numbu, Kawali, and Hitam, following completely randomized design procedures with four replications. The observation of morphological and agronomical characteristics focused on ten plants as the sample of each plot. The result showed that there were differences in the morphological and agronomical characteristics among six sorghum varieties. Varieties were assessed in terms of distinctness and grouped based on the time of panicle emergence, plant height, panicle shape, and caryopsis color. There were threeclasses as follows: Class 1, i.e., time of panicle emergence: very early (Super-1, Suri-3, Numbu, and Hitam); plant height: long (Super-1), medium (Suri-3), short (Numbu and Hitam); panicle shape: panicle broader in the upper part (Numbu), symmetrical (Super-1 and Suri-3), pyramidal (Hitam); caryopsis color: white (Super-1), grayish orange (Suri-3 and Hitam), yellowish orange (Numbu). Class 2, time of panicle emergence: early (Samurai-1); plant height: medium (Samurai-1); panicle shape: panicle broader in the lower part (Samurai-1); caryopsis color: yellowish orange (Samurai-1). Class 3, time of panicle emergence: medium (Kawali); plant height: medium (Kawali); panicle shape: panicle broader in the lower part (Kawali); caryopsis color: yellowish white (Kawali). Assessment of agronomical characteristics revealed that fresh plant weight had a significant positive correlation with plant height R1, plant height R5, stem diameter, leaf bladewidth, thousand-grain weight, and stem sugar content. Several varieties, namely Super-1, Samurai-1 and Kawali, were found to have excellent agronomical characteristics to provide a solid varietal basis for selecting varieties as phytoremediators.
... An alternative strategy is the use of plant based system (phytoremediation) to interact with the PAHs for eventual removal or degradation from soil, sediment or water (Adamu, 2019). The advantages of this strategy over conventional remediation processes are: less environmental disturbance, soil erosion prevention, control runoff and windblown dust, increase soil health and fertility, less harmful, broad range of application, environmentally friendly and high public acceptance (Erakhrumen, 2007;Rao and Babu, 2014;Adamu, 2019). ...
This study was undertaken to evaluate the phytoremediation potential of Ficus Benjamina plant for the removal of polycyclic aromatic hydrocarbons (PAHs): Acenaphthene (ACN), naphthalene (NAP) and phenanthrene (PHE) from contaminated soil. The plant was transplanted into pot containing 4 kg soil spiked with the PAHs: ACN, NAP and PHE at concentrations of 1600, 2000 and 2400 mg respectively. A separate pot with untreated soil was used as a control. Irrigation was done with 600 mL of water after every three days in the evening hours for eight weeks. Samples of the plant and soil were collected at the end of the phytoremediation process; the plant was washed with tap water and carefully separated into roots and shoots, dried along with the soil, ground and sieved. The sieved soil, roots, shoots of the experimental plant as well as that of the control were analyzed for the levels of PAHs: ACN, NAP and PHE following Soxhlet extraction with 200 mL of dichloromethane-acetone (1:1 v/v) at 60 oC for 6 hours using high performance liquid chromatography (HPLC). The bioconcentration factor (BCF) in mg/kg and the Translocation Factor (TF) in mg/kg of Ficus Benjamina for ACN, NAP and PHE were (1.76 and 0.47), (0.54 and 2.7) and (0.93 and 0.68) respectively. The results generated in this study have demonstrated that the different concentrations of the PAHs (NAP, ACN and PHE) in root, only NAP was transferred to the aerial parts of the plant and this suggests the suitability of Ficus Benjamina for the phytoremediation of NAP.
... Besides, the PTEs around the rhizosphere were also absorbed by the roots, and fixation takes place inside the roots as an insoluble form (Oustriere et al., 2017;Sampaio et al., 2019). Both hydrophytes and mesophytes are used as hyperaccumulator plants through the rhizofiltration technique (Erakhrumen and Agbontalor, 2007;Prasad, 2007). Galal et al. (2018) examined the phytoremediation capability of a macrophyte, Vossia cuspidata to absorb and bioaccumulate PTEs pollutants in wetlands. ...
Phytoremediation is a biological remediation technique known for low-cost technology and environmentally friendly approach, which employs plants to extract, stabilise, and transform various compounds, such as potentially toxic elements (PTEs), in the soil or water. Recent developments in utilising chelating agents soil remediation have led to a renewed interest in chelate-induced phytoremediation. This review article summarises the roles of various chelating agents and the mechanisms of chelate-induced phytoremediation. This paper also discusses the recent findings on the impacts of chelating agents on PTEs uptake and plant growth and development in phytoremediation. It was found that the chelating agents have increased the rate of metal absorption and translocation up to 45% from roots to the aboveground plant parts during PTEs phytoremediation. Besides, it was also explored that the plants may experience some phytotoxicity after adding chelating agents to the soil. However, due to the leaching potential of synthetic chelating agents, the use of organic chelants have been explored to be used in PTEs phytoremediation. Finally, this paper also presents comprehensive insights on the significance of using chelating agents through SWOT analysis to discuss the advantages and limitations of chelate-induced phytoremediation.
... This includes the enrichment of the valuable and reduction of compounds in concert with optimization of bioenergy production. Besides burning biomass [21][22][23], for energy followed by metal recovery from the ash [24][25][26][27] and pyrolysis [28][29][30][31][32] the biomass can be converted anaerobically to produce biogas in parallel with a digestate which can later be used for raw material recovery and thereafter returned to the soil as organic fertilizer. ...
This study investigated the effect of mesophilic (37°C) and thermophilic (55°C) digestion on the enrichment and fractionation of plant nutrients (P, Mn, Fe), potentially toxic elements (Cd, Cr, Pb, As, Cu, Ni, Co, Zn) and economically valuable elements (Ge, rare earth elements REE). Batch experiment was conducted with the substrates of Phalaris arundinacea and inoculum for 40 days and the latter digestate was collected for further analysis. Diges-tate from selected reactors was filtered through 0.2 μm syringe filters to separate dissolved elements from the particulate. The solid digestate was extracted with ammonium acetate (pH 7 and pH 5) to determine the extraction of mobile/exchangeable and acid soluble elements, respectively. In fresh digestate, element concentration increased by more than 20-100% especially Ge (94%) and REEs (119%) and pH (6.5-7.9) was significantly higher compared to mesophilic (6.1-7.5). In dried digestate, thermophilic digestion showed increased enrichment of Fe, Co, Cu, Zn, Cr, As, Cd, Pb and especially Ge (193%) and REEs (90%) compared to mesophilic indicating a strong enrichment in thermophilic digestion. Considering both operating conditions 5% of elements were present in the liquid, less than 30% were exchangeable and acid soluble and more than 70% were stabile bound into solids. Thermophilic conditions significantly increased the portion of dissolved and labile-bound elements in the digestate. Reactor temperature offers a promising way to use digestate as a secondary raw material for element recovery in the spirit of phytomining, which contributes to a "cascade use" of digestate in the circular economy .
... Soil replacement, otherwise known as soil change entails replacing polluted soil with clean and uncontaminated soil in order to reduce pollutant concentrations, improve soil absorption capacity, and achieve soil rehabilitation [78,79]. It could be a total or partial replacement of the soil. ...
Owing to the increasing industrial revolution in recent times, the pollution of aquatic and soil environments by heavy metals has been on the increase. The heavy metals generated from industrial activities can endanger humans as well as other living organisms. These heavy metals are hazardous and persist in the environment posing a great threat to public health. In order to address this serious environmental problem, gamut of remedial strategies are currently being applied with each having its merits and demerits. Interestingly, the physicochemical remediation strategies can be considered as one of the best and viable techniques in rehabilitating heavy metal contaminated sites, especially water and soil. The main advantages of the physicochemical remediation strategies stem from its high removal efficiency, speedy recovery of contaminants, ease of implementation and operational convenience. Hence, the scope of this review encompasses a brief account of heavy metal pollution, its sources, toxic effects and a critical review of the current physicochemical remedial approaches utilised in the removal of heavy metals, which ultimately restores polluted environmental media back to their original status. This study is significant, because it sensitises the general public on the dangers of heavy metal pollution and at the same time provides invaluable information to environmental scientists, public health workers and engineers who work to restore degraded ecosystems as well as sustainable ways to protect human and ecosystem health.
... The use of hyperaccumulator species is limited by slow growth, shallow root system7 and tiny biomass production. In addition, the plant biomass must also be harvested and disposed of properly, complying with standards (Dhir 2013). ...
AGRONOMIC PRACTICES FOR IMPROVING PRODUCTION IN
SAND DEPOSITED AREAS
Sand deposition on agricultural lands wereusually caused by the action of
wind/water. These sand depositions often occur in the regions which are more
prone to frequent floods/wind erosion. With the severity of the deposition, the
soil texture, structure,and nutrient status can be altered. It also makes soil not
suitable for cultivation and these problemsaggravate when more sand and silt
deposition is high. Sand deposited areas can be brought back to cultivation by
following certain agronomic measures like the addition of organic matter and
clay to soil, growing of cover crops, cultivating crops which can grow well in
sandy areas, adopting proper tillage methods, use of slow-release fertilizers,etc..
The windbreaks and shelterbeltscan be used to stop sand dunes formation in
desert areas. There are certain modern innovations like Liquid Nano Clay
particles technology to bring back the sand deposited areas to cultivation
... Although some ornamental plants with poor tolerance to heavy metals are probably not suitable for phytoremediation applications, the results of these investigations are still valuable to phytoremediation research. Phytoextraction takes advantage of plants, especially hyperaccumulator plants, to extract or concentrate metals and organics into the harvestable biomass [59], whereas phytostabilization primarily makes use of plants ability to reduce the mobility and bioavailability of contaminants [60,61]. Thus, in deciding whether an accumulator can be used for phytoextraction or phytostabilization purposes, the heavy metal accumulation in roots or aboveground shoots is a major factor. ...
... This technique is based on the potential of plant roots to uptake, translocate, and deposit heavy metals from soil to aboveground harvestable plant parts. After the completion of phytoextraction, the plant is then harvested and burnt to obtain energy and recycle metal from the ash (Erakhrumen & Agbontalor, 2007). Phytoextraction provides a solution for the elimination of metals from contaminated sites. ...
... In complement to selecting out of the agricultural specialization, soils polluted with heavy elements such as chromium, arsenic, lead, cadmium, copper, zinc, mercury, and nickel assess a significant risk to resources of groundwater through heavy elements filtering. Pollution of harvests cultivated in those soils passively impacts human health and food [3,4]. The major attraction of environmental contamination investigations is discovering creative methods to rescue the environment from pollutants' damaging impacts [5]. ...
Concerning the controlled environment and media technique in these studies, in vitro phytoremediation analyses might provide more precise and reliable findings. Hence, this chapter pursued to estimate the efficacy of the shoot and root organs of big-sage (Lantana camera (L.) Czern.) plantlets in assembling heavy metals (cadmium, cobalt, and lead) via the plant tissue culture technique. Many examinations achieved on the phytoremediation of the Lantana camara seedlings to heavy metals in vivo demonstrated that they were assembled in the shoot organs at a higher concentration compared with the root organs of this plant. Thus, L. camara can be regarded as a higher accumulation potential plant for heavy metals such as lead, chromium, cadmium, nickel, and arsenic, and a favorable plant for phytoremediation. As for the examinations executed on the effect of different levels of the heavy metals cadmium, cobalt, and lead on their assemblage and some growth traits in the shoot and root organs of the L. camera plantlets beneath in vitro culture conditions, they discovered that the assemblage of these metals in the shoot and root organs increased with the increase in the treatment level, except for the heavy metal lead, which assemblage in the roots without the shoots.
... According to Erakhrumen and Andrew (2007); there are some merits and drawbacks of the phytoremediation process which are as follows: ...
Background: According to WHO statistics, cardiovascular disease are the
leading causes of death in the world. One of the main factors which is causing
heart failure, systolic and diastolic dysfunction, and arrhythmias is a condition
named cardiac fibrosis. This condition is defined by the accumulation of
fibroblast-produced ECM in myocardium layer of the heart.
The excessive accumulation of ECM elements causes heart stiffness, tissue
scarring, electrical conduction disruption and finally cardiac dysfunction and
heart failure.
Objective: To describe the role of curcumin in the regulation of different
signaling pathways that are involved in cardiac fibrosis.
Results: Curcumin is a natural Indian medicine which currently has been
declared to have therapeutic properties such as anti-oxidant and
immunomodulatory activities, which prevents oxidative stress, inflammation,
and mechanical stress involved in cardiac fibrosis. In this review, we havegathered several experimental studies in order to represent diverse impacts of
this turmeric derivative on pathogenic factors of cardiac fibrosis.
Conclusion: Curcumin will open a new way in the field of cardiovascular
treatment.
Keywords: ECM (Extra cellular matrix), curcumin, cardiac fibrosis, cardio
protective.
... Phytoremediation is an in-situ remediation technology based on the ability of plants to fix pollutants from the soil under the concept of using nature to cleanse nature ( (Erakhrumen, 2007). This approach can replace clean-up technologies that are often laborious and costly. ...
Phytoremediation is an in-situ remediation technology based on the ability of plants to fix pollutants from the soil. In this sense, plants such as Festuca arundinacea are a promising for heavy metal removal in contaminated soils. The present work studies phytoremediation for Pb removal from a contaminated soil located in Spain using F. arundinacea by applying the Life Cycle Assessment (LCA) approach. Two different options for biomass management were assessed: direct disposal in a security landfill (case 1A) and energy recovery (case 1B). For the latter option, cogeneration was simulated using SuperPro Designer 9.5. In addition, traditional treatments such as soil washing (case 2) and excavation + landfill (case 3) were evaluated in terms of environmental impacts by LCA. The former was simulated using SuperPro Designer 9.5, whereas data from literature were used for the latter to perform the LCA. Results showed that biomass disposal in a landfill was the most important contributor to the overall impact in case 1A. In contrast, biomass conditioning and cogeneration were the main steps responsible for environmental impacts in case 1B. Comparing cases 1A and 1B, the energy recovery from biomass was superior to direct landfill disposal, reducing the environmental impacts in most of the studied categories. Regarding the rest of the treatments, chemical production and soil disposal presented the most critical environmental burdens in cases 2 and 3, respectively. Finally, the comparison between the studied cases revealed that phytoextraction + energy recovery was the most environmentally friendly option for the studied conditions, reducing impacts by 30-100%.
... In this, the metals are absorbed or adsorbed and thus their movement in underground water is minimized. In addition to the above process, phytostabilization or phytoimmobilization occurs, which reduces the mobility and bioavailability of metals in the environment and thus prevents their migration into groundwater or the food chains (Erakhrumen, 2007). Organic pollutants taken by plants are metabolized by enzymes such as dehalogenase and oxygenase, which are not dependent on rhizospheric microorganisms (Vishnoi and Srivastava, 2008). ...
This communication attempts to provide a brief review on toxic heavy metals, their
sources and effect on living system and environment with special emphasize on lead,
mercury, cadmium and arsenic heavy metals. Further the review addressed mitigation
measures of heavy metals focused on bioremediation. Any toxic metal called heavy metal
irrespective of their atomic mass or density. Generally, heavy metals are the natural
components of earth crust. Even in trace amount, some heavy metals are essential for
living beings viz, Copper, Selenium, and Zinc, but excess amount of heavy metal may
cause serious environmental and health problems. Most of the heavy are hazardous
because they are tends to bio-accumulating in living cells. Heavy metals enter into
the groundwater, soil as well as the surface water and further contaminate the food
resources, by accumulating into the herbs and grains. They can alter the flora and fauna
of an ecosystem. Pesticides, herbicides, certain fertilizers, paints, automobile batteries, herbal medicines and Ayurvedic bhasma are the major anthropogenic source of heavy
metal contamination or toxicity. Moreover the fatal incidence related to heavy metal
toxicity, has been reported worldwide in past few decades. Therefore the removal and
management of heavy metals pollutants is necessary for health and safety concern.
Several microorganisms and plant species are being used to neutralize toxic effects of
heavy metals contaminants. Bioremediation of heavy metals is sound alternative to
remove toxic heavy metals from environment.
... Phyto-extraction, commonly known as phytoaccumulation, is the process by which heavy metals are absorbed in root system and subsequently translocated to an aerial component of a plants such as buds, leaves, etc. After phyto-extraction, plants may be gathered and burnt to produce energy as well as, if necessary, recover/recycle metals from the ashes (Erakhrumen, 2007;Chandra et al., 2018). Phyto-remediation and phytoextraction are often used interchangeably, and this is misleading, phyto-extraction is a cleaning procedure but phyto-remediation seems to be the title of a principle (Prasad et al., 2005). ...
Heavy metal pollution is a significant source of pollution in the environment. Heavy metal contamination in aquifers endangers public health and the freshwater and marine ecosystems. Traditional wastewater treatment methods are mainly expensive, ecologically damaging, ineffective, and take much time. Phyto-remediation is a plant-based technique that gained popularity by discovering heavy metal accumulating plants that can accumulate, transport, and consolidate enormous quantities of certain hazardous contaminants. This is a low-cost sustainable evolving technique featuring long-term utility. Several terrestrial and aquatic vegetation have now been examined for their ability to repair polluted soils and streams. Several submerged plants have already been discovered to remove harmful pollutants such as Zn, As, Cu, Cd, Cr, Pb & Hg. The most important part of effective phyto-remediation is selecting and choosing effective plant species. Aquatic macrophytes have high effectiveness for removing chemical contaminates. Watercress, hydrilla, alligator weed, pennywort, duckweed plants, water hyacinth are examples of aquatic macrophytes. Several macrophytes' metal absorption capability and procedures have now been explored or analyzed. Most of these research demonstrated that macrophytes had bioremediation capability. The bioremediation capability of macrophytes can be increased even more by employing novel bioremediation techniques. To demonstrate the extensive application of phyto-remediation, a comprehensive summary assessment of the usage of macrophytes for phyto-remediation is compiled.
... The plant may reduce the mobility of As into groundwater and also check it to reach other parts of plant. These tolerant plant root exudates stimulate microbial activity for the stabilization of heavy metals (immobilizing forms) in soil [25,26]. Phosphate and arsenate both aquaporin transport channels are provided path to As entry in plant system [27][28][29][30][31]. ...
The presence of arsenic in water is linked not only to health concerns, but also to the socioeconomic conditions of a huge population in poor countries. The severity of As-poisoning might be accelerated by poor health and nutritional status. Many people suffer from pre-cancerous skin keratosis, Bowen's disease, and Arsenicosis, among other conditions. Long-term exposure can cause cancer. For in vitro screening of As tolerant plant, four plants viz., Triticum aestivum, Lycopersicon esculentum, Solanum melongena, and Capsicum annuum, were raised in As amended triple sterilized soil and sand mixture (1:1 ratio). L. esculentum and S. melongena could survive up to 100 ppm but extremely poor growth and biomass were recorded. The maximum tolerance was recorded in T. aestivum up to 150 ppm, whereas least survival was recorded for C. annuum.
... Metals accumulated by A. viridis would be channelled to the root tissues through phytostabilisation processes or transported through xylem vessels to the aerial parts of the plant. The various mechanisms in the roots of phytostabilisers involved adsorption, precipitation, and complexation [85]. ...
Human health risk and phytoremediation of potentially toxic metals (PTMs) in the edible vegetables have been widely discussed recently. This study aimed to determine the concentrations of four PTMs, namely Cd, Fe, Ni, and Zn) in Amaranthus viridis (leaves, stems, and roots) collected from 11 sampling sites in Peninsular Malaysia and to assess their human health risk (HHR). In general, the metal levels followed the order: roots > stems > leaves. The metal concentrations (µg/g) in the leaves of A. viridis ranged from 0.45 to 2.18 dry weight (dw) (0.05–0.26 wet weight (ww)), 74.8 to 535 dw (8.97–64.2 ww), 2.02 to 7.45 dw (0.24–0.89 ww), and 65.2 to 521 dw (7.83–62.6 ww), for Cd, Fe, Ni, and Zn, respectively. The positive relationships between the metals, the plant parts, and the geochemical factions of their habitat topsoils indicated the potential of A. viridis as a good biomonitor of Cd, Fe, and Ni pollution. With most of the values of the bioconcentration factor (BCF) > 1.0 and the transfer factor (TF) > 1.0, A. viridis was a very promising phytoextraction agent of Ni and Zn. Additionally, with most of the values of BCF > 1.0 and TF < 1.0, A. viridis was a very promising phytostabiliser of Cd and Fe. With respect to HHR, the target hazard quotients (THQ) for Cd, Fe, Pb, and Zn in the leaves of A. viridis were all below 1.00, indicating there were no non-carcinogenic risks of the four metals to consumers, including children and adults. Nevertheless, routine monitoring of PTMs in Amaranthus farms is much needed.
... This is assisted by endocytic bacteria that colonise the plant inner tissues without causing any side effects on their host (plant) [59,75]. Persistent organic pollutants (POPs) can be abated with phytoremediation techniques as reported by Erakhrumen and Agbontalor [76]. • Phytostimulation Phytostimulation (also known as rhizodegradation) is the technique where the plants release certain substances through their roots into the soil or groundwater. ...
Air pollution is a global environmental issue, and there is an urgent need for sustainable remediation techniques. Thus, phytoremediation has become a popular approach to air pollution remediation. This paper reviewed 28 eco-friendly indigenous plants based on both the air pollution tolerance index (APTI) and anticipated performance index (API), using tolerance level and performance indices to evaluate the potential of most indigenous plant species for air pollution control. The estimated APTI ranged from 4.79 (Syzygium malaccense) to 31.75 (Psidium guajava) among the studied indigenous plants. One of the selected plants is tolerant, and seven (7) are intermediate to air pollution with their APTI in the following order: Psidium guajava (31.75) > Swietenia mahogany (28.08) > Mangifera indica L. (27.97) > Ficus infectoria L. (23.93) > Ficus religiosa L. (21.62) > Zizyphus Oenoplia Mill (20.06) > Azadirachta indica A. Juss. (19.01) > Ficus benghalensis L. (18.65). Additionally, the API value indicated that Mangifera indica L. ranges from best to good performer; Ficus religiosa L. and Azadirachta indica A. Juss. from excellent to moderate performers; and Cassia fistula L. from poor to very poor performer for air pollution remediation. The Pearson correlation shows that there is a positive correlation between API and APTI (R2 = 0.63), and this implies that an increase in APTI increases the API and vice versa. This paper shows that Mangifera indica L., Ficus religiosa L., and Azadirachta indica A. Juss. have good potential for sustainable reduction in air pollution for long-term management and green ecomanagement development.
... Phytoremediation is an environmentally sound technology and is cost-effective for remediation of saline soil, given it is properly developed. In the wake of this issue, applications of halophytes best practice are seen in not only desalinization/remediation but also in the agriculture/agroecological sector as in the forage industry (Erakhrumen and Agbontalor 2007). It is imperative to select plants which have Table 3.2. ...
Salinity is an increasingly urgent problem causing tremendous yield losses on a global scale. The problem is a marked imperative in arid and semiarid regions. To maximize crop productivity, and alleviate environmental stress, these areas require either reduction of salinity or the use of salt-tolerant crops. Halophytes are plants capable of normal growth in saline habitats and are able to thrive on “ordinary” soil, though these plants have a capacity to tolerate concentrations over 0.5% throughout their life cycle. As a consequence of rapid climate change, the proportion of saline areas is increasing daily, providing motivations for development of salt-tolerant crops to cope with the adverse conditions and contribute to long-term sustainability goals.Research efforts are directed toward studying phytoremediation of saline environments in order to efficiently ameliorate salts from both soil and water. Challenges of attaining sustainable environments need to be addressed through mitigating global climate change while enabling a cooperatively sustained food industry. Many features of halophytes are highlighted in this chapter, easing the improvement of salt tolerance in crops in the future. Genetic and physiological screening of halophytes facilitates the contribution of halophytes with respect to long-term environmental sustainability.KeywordsHalophytesSalt-responsive genesSalinityPhytoremediationEnvironmental sustainabilityCrop modification
... Previous studies in the field of metal contamination of agricultural soils indicated that phytoremediation is an interesting and suitable option to remediate contaminated sites, as it provides a green solution of the problem that is socially acceptable and economically feasible (Salt et al. 1995;Garbisu and Alkorta 2001;Rew 2007;Seth 2012;Ali et al. 2013). However, traditional phytoremediation approaches, i.e., use of hyper-accumulator plants to extract metals from contaminated soils posses certain limitations as discussed in detail in previous sections. ...
Nickel (Ni) element is strongly phytotoxic at high concentrations for several plants, but due to its dual behavior and complicated chemistry, it has received little attention in plant nutrition and relevant experimental data are limited. The current research was carried out to study the effect of Ni on maize (Zea mays L.) growth and phytoextraction potential with EDTA assistance, a process termed as chemical assisted phytoremediation. Treatments included two levels of EDTA (0 and 0.5 mM), two levels of Ni (0 and 40 µM) and their combination (EDTA+Ni) that were applied to maize plants grown in a pot experiment. Application of Ni alone or in combination with EDTA reduced maize root and shoot length by 7.8% to 13.3% and by 15.6% to 21.1%, respectively, compared with control, as well as root and shoot dry weight by 42.0% to 60.0% and by 29.8% to 46.6%, respectively. A similar declining trend was observed also for the content of photosynthetic pigments (chl-a, chl-b, total chlorophyll, and carotenoids) as well as total proteins. However, proline, total soluble sugars, and free amino acids showed an increasing trend with application of Ni and EDTA alone or in combination. These treatments significantly decreased P and Na content in maize roots, stems, leaves, and grains, while increased K content compared with control. Application of EDTA with Ni was the most effective treatment to enhance Ni accumulation in maize (50.23 mg per plant) compared with Ni alone (40.62 mg per plant), EDTA alone (27.75 mg per plant), and control (15.51 mg per plant). Application of EDTA in combination with Ni enhanced Ni accumulation by 4.9 folds in maize shoots and by 2.6 folds in roots over control. In conclusion, application of EDTA in suitable concentrations may enhance Ni uptake by maize providing an effective and economic phytoremediation method of Ni-contaminated soils.
... Phytoextraction is likewise called phytoaccumulation, and it includes the take-up of heavy metal in the plant roots and afterward their movement into an over-theground-level bit of the plantlike shoots, and so on. When the phytoextraction is done, the plant can be reaped and consumed for picking up vitality and recuperating/reusing metal whenever required from the debris (Erakhrumen, 2017;Chandra 19.3 Results and discussion 373 Table 19.2 Aquatic micro/macrophytes for phytotechnologies to treated natural, inorganic, radionuclides toxins, industrial effluents, corrosive mine seepage, saltwater, the guideline of water, and expulsion of different physiccompound boundaries including HMs COST action 859, 2005;Farahdiba et al., 2020;Muthukumaran and Sivasubramaian, 2017;Prasad, 2007). ...
Human activities have become the source of myriad pollutants and have accelerated the pressure on natural resource depletion. Intensive farming, urbanization, rapid industrialization, and other human activities have resulted in land deterioration and degradation, a polluted environment, and a downturn in crop productivity across various sectors of agriculture. Several alternative methods have been designed and developed, but often, these processes risk environmental damage by producing secondary pollutants. Biological treatment systems have diversified applications, such as the cleanup of site contaminants in soil, water, streams, and sludge. Bioremediation, an efficacious and lucrative eco-friendly management tool, utilizes microorganisms to degrade or reduce the concentration of hazardous wastes at the contaminated site without causing additional deterioration of the environment. This chapter discusses the role of a vast array of microorganisms used in the reclamation of wastewater containing metal pollutants through bioremediation and puts forward thoughts and opportunities for further research in the field.
... Addressing the consequences of land degradation is achieved through strategies for vegetation fly ash deposits and areas destroyed. (1)(2)(3)(4)(5)(6)(7)(8) Revegetation strategies may offer more opportunities, such as: -Installing a tolerant vegetation to environmental conditions and do not accumulate heavy metals in aerial plant tissue. In this case, it results a biomass that can be harvested and used without risk of spreading pollutants in soil, water, food, etc. ...
Fossil coal combustion in power plants is a principal energy sources in World but our residues can be considered as a waste. Disposal residues as landfills are under environmental regulations and laws. It is desirable the revegetate these sites to stabilize surface fly ash against water and wind erosion and for aesthetic landscape. Vegetation to disposal sites of fly ash resulting from coal combustion is possible in a short time by fertilization with municipal sludge its own or mixed with indigenous volcanic tuff, with clinoptilolite. Synergistic effect of municipal sludge (biosolids) with volcanic tuff determines vegetation cover up to 60-65% and reduces the bioavailability of toxic metals in soil. Treatment with biosolids and biosolids with volcanic tuff reduces the bioavailability of Cr. and Pb. and up to 50% Ni. Cu bioaccumulation is reduced with 11.6 -22.8%.
... This technique is dominantly used for remediation of groundwater, wastewater, or surface water contaminated by metals or organic and inorganic compounds [59]. When plants exceed the saturation limit of contaminants, they act similarly to phytoextraction. ...
Most of the world’s population is exposed to highly polluted air conditions exceeding the WHO limits, causing various human diseases that lead towards increased morbidity as well as mortality. Expenditures on air purification and costs spent on the related health issues are rapidly increasing. To overcome this burden, plants are potential candidates to remove pollutants through diverse biological mechanisms involving accumulation, immobilization, volatilization, and degradation. This eco-friendly, cost-effective, and non-invasive method is considered as a complementary or alternative tool compared to engineering-based remediation techniques. Various plant species remove indoor and outdoor air pollutants, depending on their morphology, growth condition, and microbial communities. Hence, appropriate plant selection with optimized growth conditions can enhance the remediation capacity significantly. Furthermore, suitable supplementary treatments, or finding the best combination junction with other methods, can optimize the phytoremediation process.
... Phytoextraction is likewise called phytoaccumulation, and it includes the take-up of heavy metal in the plant roots and afterward their movement into an over-theground-level bit of the plantlike shoots, and so on. When the phytoextraction is done, the plant can be reaped and consumed for picking up vitality and recuperating/reusing metal whenever required from the debris (Erakhrumen, 2017;Chandra 19.3 Results and discussion 373 Table 19.2 Aquatic micro/macrophytes for phytotechnologies to treated natural, inorganic, radionuclides toxins, industrial effluents, corrosive mine seepage, saltwater, the guideline of water, and expulsion of different physiccompound boundaries including HMs COST action 859, 2005;Farahdiba et al., 2020;Muthukumaran and Sivasubramaian, 2017;Prasad, 2007). ...
Bioremediation is an option to transform toxic heavy
metals into a less harmful state using microbes or their enzymes and is an ecofriendly,
cost-effective technique for revitalizing wastewater-polluted environments
... This process limits the movement of contaminants, prevents their entry into the food chain, and ultimately reduces their bioavailability. This technique is used to decrease the bioavailability and mobility of pollutants in the environment, preventing their migration to groundwater or entry into the food chain [18]. Plants can immobilize heavy metals in soils by root uptake, precipitation, complexation, or valence reduction of metals in the rhizosphere [19][20]. ...
Soil pollution by heavy metals has become a global problem, as soil contamination by pollutants of mineral origin poses many risks to the environment and human health. To cope with this problem, researchers have developed many treatment techniques, and among these techniques is a botanical treatment which depends on the use of plants called heavy metal bioaccumulating plants to clean up contaminated soils, this technique has several processes such as phytoaccumulation, phytovolatilization, phytoextraction, phytodegradation etc. this review deals with the different mechanisms involved in phytoremediation, their advantages/limitations, the factors influencing bioaccumulation and mobility of metals in soil, and the different families of heavy metal bioaccumulating plants.
... There are numerous procedures present that evacuate heavy metals but they all are costly. Therefore, it is necessary to develop such systems which are eco-accommodating and financially savvy for getting the waste metals expel from the environment (Erakhrumen and Agbontalor, 2007;Idrees et al., 2017). Phytoremediation is a technology in which eliminates dangerous substances from the environment with the help of plants and micro organisms that present soil. ...
The present study was carried out to determine the potential for phytoremediation of water hyacinth (Eichhornia crassipes) plant for Cadmium (Cd), Arsenic (Ar), and Mercury (Hg) absorption. The samples were collected from Dhamthal, Zafarwal and Narowal. The plant samples were cut into their parts and dried at room temperature for 25-30 days until they were fully dried. The change in fresh weight and dry weight was examined. The data of collected samples was recorded and statistically analyzed, which revealed the significance of results for different localities. The lower coefficient of variation was recorded for all studied traits which revealed that there was consistency among the results for different localities. For our study the plant's percentage removal of metals was determined using atomic absorption spectroscopy in plant sample as well as water sample. Metal uptake happened at variable degrees. The water hyacinth uptake the largest metal uptake per dry weight of water hyacinth was 166.25ppm for cadmium and the smallest 0.032ppm was for mercury. In water sample highest amount of metal was 177.25ppm for cadmium and lowest 0.012ppm was for arsenic. It was found from our study that the water hyacinth (Eichhornia crasssipes) uptake cadmium (cd) metal from sewage water in highest amount as compare to arsenic and mercury. It was suggested that the use of water hyacinth plant may be helpful to remove heavy metals from waste water to minimize the heavy metal pollution of water.
Soil degradation is a combination of natural and anthropogenic processes that lead to changes in soil functions, quantitative and/or qualitative deterioration of composition and properties, and a decrease in the natural and economic significance of lands. The state of the soil cover in Russia is far from satisfactory, and in some areas even critical. The Murmansk region is highly industrialized and urbanized region in the Arctic zone. We have tested the acute and chronic phytotoxicity of various industrial materials (expanded vermiculite, nepheline waste and quartz waste), urban and suburban soils of industrial, traffic and recreational zones, soil of urban farm, and conditionally background soil. The water-soluble, plant available, and acid-soluble metal fractions were analyzed. To assess the acute toxicity of industrial wastes, pre-grown hydroponic lawns from Lolium spp. were used, and the duration of the experiment was 7 days. The chronic toxicity was assessed using marigolds (Tagetes spp.), after 28 and 60 days. The highest level of metals was found in soils of the suburban zone near the plant of nonferrous metallurgy and in the traffic zones, but it was revealed that the presence of nutrient elements in high concentrations can partly neutralize the toxic effect of these soils. Phytotesting showed that the weak acceleration of roots to the substrate after 3–7 days of exposition is the express indicator of the presence of high concentrations of toxic metals in the substrates and an unfavorable pH level. Thus, we propose the following low-cost algorithm for the rapid field assessment of soil phytotoxicity in the Subarctic: testing of acute phytotoxicity using hydroponic lawns; testing of chronic phytotoxicity using marigolds in case when acute phytotoxicity is absent; the chemical analysis of mobile fractions of heavy metals and nutrients only for soils which revealed the toxic effect to develop the recommendations for improving soil quality or to make decision about their replacing.KeywordsLawnMarigoldPhytotoxicityUrban soilIndustrial wasteSubarctic
Conventional treatment technologies are costly, time-consuming, and inefficient. Phytoremediation is a cost-effective emerging technology for treatment of wastewater using water plants. It is a waste utilization process with the help of specific water plants. Thus, selection of plants is the most important or significant aspect for phytoremediation success. The potential of aquatic plants can be enhanced by application of new and innovative approaches. These water plants help in removal of contaminants and heavy metals from polluted water. The prominent metal accumulator are water hyacinth, water lettuce and duckweed.
This chapter emphasizes on post‐mining reclamation techniques of disturbed lands as a result of mining. As mining poses serious environmental threats and deleterious effects on the landscape, reclamation is a challenge and requires elaborate planning much before mines are opened. In this chapter, a detail regarding proper reclamation strategies including probable bio‐geotechnologies including phytoremediation, nanotechnology, silviculture, transgenics effective in mine land restoration is presented. Land reclamation has been a matter of concern to counter the negative impacts of mining and address the issues of landscape remodeling. The chapter highlights the major techniques beneficial for the strategic and sustainable reclamation of disturbed mine lands and to return the aesthetic pleasure of the land site which can be commercially and agronomically productive and suitable for future use. The basic proposal for land reclamation requirements and various methods implied for mine land restoration are discussed elaborately in this chapter.
Heavy metals (Pb, Cd, Ni, Co, Fe, Zn, Cr, As, Ag, platinum group, etc.) in trace amounts are natural components of the environment. However, their presence in excess may cause a serious threat to the stability of the ecosystem by inducing a drastic change in the quality and yield of crop products. Heavy metal toxicity in the agro-ecosystem has now become a major challenge for the planet. To increase crop productivity, it is necessary to evolve efficient, low-cost technologies for reducing metal toxicity. Many appropriate technologies are available for removing or reducing such toxicants but as a cost-effective, eco-friendly, and sustainable method—phytoremediation is gaining worldwide attention for its effectiveness. In the present book chapter, we attempt an overview of current knowledge on the roles of several species of plants from the family Brassicaceae as metal hyper-accumulators. Characteristics of plant species of Brassicaceae as phytoremediators of heavy metals, detailed mechanisms of phytoremediation by plants from the Brassicaceae family, and methods to enhance heavy metal phytoextraction by using chelating chemicals or through biotechnology and genetic engineering have been focused.
For the normal growth and functioning, along with the macronutrients, plants also require essential micronutrients such as Cu, Zn, Mn, Fe, Ni, and Co, but they are needed in very small quantity; if the concentration and accumulation of these elements exceed the limits, it will become toxic to the plants. Here we can see the role of metal transporters; they aid in absorption, sequestration, and storage of these metals. This chapter focuses on the importance and the functions of the metal transport protein classes like CDF family, NRAMPs, ZIP family, ABC transporters, and CAX family in maintaining metal homeostasis. Another issue is that due to high concentration of heavy metals in the soil, these enter into the food chain which may pose threat to the human population; hence the context of phytoremediation becomes pertinent, which is a technique where hyperaccumulating plants/trees are grown for the removal or remediating the heavy metals present in the soil. We explain about various aspects taken into account to estimate the potential of the plant in sequestering the heavy metals from the soil, various ways of phytoremediation. Now-a-days, we are putting loads of pressure on land and resources to increase the yield of the product, but very little emphasis is given on improving (especially micronutrients) and conserving the nutritional qualities of the product; therefore, we can see that malnutrition is becoming very prominent in this era where about half of the world population suffers from the malnutrition of iron, zinc, and selenium; hence, biofortification comes into account, in which plants can be fortified either by agronomic practices or through breeding or by using biotechnological approaches.
This study investigated the effect of mesophilic (37°C) and thermophilic (55°C) digestion on the enrichment and fractionation of plant nutrients (P, Mn, Fe), potentially toxic trace elements (Cd, Cr, Pb, As, Cu, Ni, Co, Zn) and economically valuable elements (Ge, rare earth elements REEs). Batch experiment was conducted with the substrates of Phalaris arundinacea and inoculum for 40 days and the latter digestate was collected for further analysis. Digestate from selected reactors was filtered through 0.2 µm syringe filters to separate dissolved elements from the particulate. The solid digestate was extracted with ammonium acetate (pH 7 and pH 5) to determine the extraction of mobile/exchangeable and acid soluble elements, respectively. In fresh digestate, element concentration increased by more than 20 to 100% especially Ge (94%) and REEs (119%) and pH (6.5–7.9) was significantly higher compared to mesophilic (6.1–7.5). In dried digestate, thermophilic digestion showed increased enrichment of Fe, Co, Cu, Zn, Cr, As, Cd, Pb and especially Ge (193%) and REEs (90%) compared to mesophilic indicating a strong enrichment in thermophilic digestion. Considering both operating conditions 5% of elements were present in the liquid, less than 30% were exchangeable and acid soluble and more than 70% were stabile bound into solids. Thermophilic conditions significantly increased the portion of dissolved and labile-bound elements in the digestate. Reactor temperature offers a promising way to use digestate as a secondary raw material for element recovery in the spirit of phytomining, which contributes to a “cascade use” of digestate in the circular economy.
Man has come a long way from nomadic life to the present age through the corridor of technological advancement. In this transit, a wide range of anthropogenic activities have changed the homeostatic mechanism and disturbed the ecological balance. The various industrial processes, combustion of fossil fuels, agricultural activities along with natural processes distribute the heavy metals in the ecosystem, disperse in air, accumulate in water and soil impacting the health of the planet. Fe and Mn are essential as cofactors of various enzymatic reactions and required at low levels, higher concentration can be detrimental to health. Most other heavy metals are toxicants, they are non-biodegradable, bioaccumulate and bio-magnify in higher trophic levels causing adverse effects. Coastal water often serves as the final destination of all wastes, in which heavy metals are important components. Hence there is a need to remediate the coastal and estuarine water in an economical manner. The various physical and chemical treatment processes of heavy metal removal from wastewater have many limitations so attention has shifted to methods which are economical and environmentally friendly like phytoremediation, wherein plants are used to eliminate the heavy metals. Phytoremediation includes phytoaccumulation, phytostabilization, phytodegradation, phytovolatilization and hydraulic control. In this article we have emphasized on the elimination of heavy metals from coastal water using endemic coastal vegetations that encompass mangroves and saltmarsh grass, collectively known as blue carbon.KeywordsHeavy metalsCoastal and estuarine waterBiopurificationPhytoremediationCoastal vegetations
Hazardous contaminants due to natural process and anthropogenic activities pose serious health and environment risk which is a global problem. To mitigate this problem, phytoremediation, a plant-based approach of remediating organic and inorganic environmental pollutants from the soil and water, is practiced. It is an eco-friendly and cost-effective approach which involves plants to clean up the environment. A series of remedial strategies with distinct mechanism were employed for the degradation or removal of toxic compounds. A wide geographical spread, high environmental adaptation, resilience in toxicity, and bioaccumulation potential of pteridophytes facilitate broad application in the field of phytoremediation. This chapter discusses the potential and importance of pteridophytes as remediation agents of polluted environment.
Natural resources are continuously depleted globally, and accelerated climate change is a consequence of irresponsible human action. Planetary resources have to be better utilized not to threaten living ecosystems, the biodiversity and cause further land degradation. New nature-based and cost-effective materials are appearing for remediation purposes but need continued development since they require extra knowledge about structure-function relations. Within emerging circular economy new waste streams are detected which can serve as substrate for new valuable and smart materials and at the same time provide energy and even carbon removal. Biomass has been generated from both agriculture and forestry but lately also municipal solid waste has been recognized as resource in waste valorization. Waste can be converted to new products by hydrothermal processes that yield hydrochar and thermal pyrolysis processes to produce biochar; a multiuse carbon material. Ideal waste utilization processes have good energy yield at the same time as new materials are formed. Carbon removal can become a part of environmental societal solutions dealing with sustainable waste processing and application of new value-added products coming from development of new smart materials. Carbon removal efforts are currently supported through the voluntary market and the total value of global carbon markets grew by over 20% in 2020 – the fourth consecutive year of record growth. This chapter displays different waste streams and their suitability for thermal treatments to produce hydrochar or biochar for understanding of how the choice of feedstock together with optimization of thermal process parameters will give best smart products.KeywordsCarbon removalChemical and physical activationMunicipal solid waste (MSW)RemediationWaste streams
Heavy metals among the other contaminants present in the environment pose a great threat. Natural activities as well as many human activities have contributed to alarming levels of heavy metals contamination in the environment. These contaminants migrate into non-contaminated areas by the process of leaching through the soil or by spreading through the sewage sludge. Several methodologies are being used in order to clean up the environment from these contaminants, but most of the methodologies are costly as well as do not give their best results. Various physical and chemical methodologies tend to generate sludge, thus increasing the costs. These physico-chemical technologies tend to render the land usage as they remove all the nutrients from the soil. Currently, phytoremediation is the most preferred technology for an effective as well as affordable solution which can be used to extract or remove the inactive metals and metal pollutants from contaminated soil and water. Phytoremediation is an eco-friendly as well as a cost-effective technology. In this chapter we would discuss about phytoremediation technology, including the heavy metal uptake mechanisms and various studies related to phytoremediation. In this chapter we also review the advantages of this technology used in order for reducing them, along with heavy metal uptake mechanisms in phytoremediation technology as well as various factors affecting these uptake mechanisms. Also plants capable of phytoremediation along with their capabilities to reduce the contaminants have also been discussed.KeywordsBioremediationPhytoremediationHeavy metalToxic compoundsEco-friendly
Current demographic trends, the ascent of immedicable diseases, access to inexpensive generic treatments, and the advent of lifestyle drugs have been pivotal causes of the increased production of biomedical wastes throughout the world. The seemingly endless stream of biomedical wastes has become a topic of global concern and implications due to their presence in surface water, groundwater, soil, etc., and cognate repercussions on vertebrates, invertebrates, and ecosystem structures and functions. Microbes can assist in environmental restoration by binding, oxidizing, volatilizing, immobilizing, or otherwise transmuting pollutants. Bioremediation has the potential to reinstate polluted environments inexpensively yet effectively. The present chapter justifies the need for bioremediation and proffers a holistic study on the development of novel methods and technologies to deal with biomedical wastes. Employing biological surface-active agents produced from microbes has gained considerable attention due to their diverse applicability, biodegradability, low toxicity, effectiveness at extreme conditions of pH and temperature, and low-cost substrates. We discuss the latest progress made and the main properties of biosurfactants followed by an overview of their current use in bioremediation. A thorough investigation on efficacy and toxicity is performed to identify potential limitations and the causes of failures.
Contamination is the appearance of pollutants into the common habitat that causes unpromising change. Water pollution, alongside the restricted accessibility of water, has put extreme pressure on life on earth. Around 40% of the world's populace confronts water shortages because of the atmosphere. Inorganic and organic pollutants, radionuclides, and heavy metals—for example, Pb, Zn, Cu, Cd, As, Ni, Co, and Fe—are some of the most harmful contaminants and come with dangerous consequences for every living organism. Conventional treatment technology to eliminate wastewater contamination is typically expensive, tedious, naturally ruinous, and generally wasteful. Bioremediation (any biological organisms), phytoremediation (plants), and phycoremediation (algae) are cost-effective and eco-friendly green technologies. Aquatic macrophytes are directed by an assortment of algal and macrophytic species in numerous natural surroundings. The determination of plant species is the most critical task for effective phytoremediation. Aquatic plants are powerfully effective in the evacuation of biological and inorganic toxins. The Azolla filiculoides, Chara sp., Eichhornia crassipes, Lemna minor, Mougeotia sp., and Pistia stratiotes alongside other aquatic plants are noticeable metal aggregators for the remediation of heavy metal-contaminated water. The phytoremediation capability of the aquatic plant can be upgraded using inventive methodologies in phytoremediation. A summary audit of the utilization of aquatic plants in phytoremediation is assembled to introduce the expansive materialness of phytoremediation.
The quality of life on earth is completely dependent on the environment. The aquatic and terrestrial systems are the two major ecosystems on earth. In ancient times, our natural systems were efficient at absorbing and breaking down pollutants and maintaining the quality of our environment. But now, owing to population explosion, rapid industrialization, and urbanization, humans have produced and added a tremendous number of pollutants in enormous volumes to the environment. As a result, our environment has become polluted and unhealthy. There are various types of pollution, e.g., water, air, soil, noise, and thermal. The invention of modern technologies to exploit natural resources has also aggravated the rate of pollution. The problem of environmental pollution can be mitigated in many ways, but the most suitable methods are biological, in which green plants are used. These plants can absorb and degrade pollutants and act as both biomitigators and bioindicators. Aquatic plants can be used to treat water pollution, and terrestrial plants can be grown around industrial and urban areas to treat air pollution. The utilization of plants to treat pollution is known as phytoremediation. This treatment is considered an ecologically sustainable and cost-effective strategy to alleviate water and air pollution. In the present chapter, we discuss the role of higher plant species in mitigating pollution and the mechanisms they use.
Environmental contamination is increasing day by day due to different natural and anthropogenic activities that lead to the soil, water, and food chain contamination. This becomes a major challenge to decontaminate the natural environment. Thus, ultimately the environmental pollutants are being taking tolls from the living being of this planet. There are a lot of potential approaches to remove pollutants from the environmental matrices including the phytoremediation. The phytoremediation is a low-risk and environmentally friendly clean-up method where plants are used to decontaminate the environment. In this chapter, efforts were given to accumulate and synthesize the published research data on phytoremediation technologies with their principles, mechanisms, and application to remove the contaminants from the soil and water environment. Phytoremediation techniques including phytoextraction, phytofiltration, rhizofiltration, phytostabilization, phytodesalination, phytodegradation, phytovolatilization, and phytomining are briefly discussed. Based on the recent literature, organic, inorganic, desalination, and wastewater treatment through phytoremediation techniques were presented with the achieved outcome. Fundamental considering factors such as enrichment factor, bioaccumulation factor, bio-concentration factor, phytodesalination capacity were also presented here. A comprehensive spectrum of potentially applicable phytoremediators was listed in this chapter which might open up the opportunity to advance further research in this particular remediation technique. Moreover, this chapter also gives an overview of the advantages and limitations of the phytoremediation techniques. In addition, post-harvest safe management of phytoremediator plants was also discussed. This chapter might be a good source of scientific evidence on phytoremediation that will be useful for the further advancement of research in this particular field.
Soil mitigation is an approach to reduce the soil degradation occurring in all aspects. Soil contamination mainly happens due to release of varieties of inorganic and organic constituents into soil. Presence of highly poisonous contaminants into soil in high concentrations is enough to cause a threat to ecosystem and on human health. Sustainable approaches can be designed by the direct and indirect utilization of microbes and plants to reduce the soil pollution load. The utilization of microbes with plants in “synergy” is considered as one of the most fruitful approaches for the removal of soil pollutants. It is well known that plant host a variety of microbes in their roots, rizosphere, and shoot by giving them essential environment to flourish and colonize. Similarly, microbes benefit by making available certain soil nutrients to plants and also help in maintaining the overall health of soil. This chapter will emphasize the problems related to soil degradation by metals, pesticides, and hydrocarbons, and their remediation by the utilization of plant-microbial synergism system.
The growth of the plant mainly depends upon the mineral nutrition of the plants and the mineral nutrition is obtained mainly from the soil. Soil contains a lot of nutrients, metals and is absorbed by the plant's roots. The root hair accumulates the nutrients as well as the toxic elements which are then transported from below-ground parts of the plant to the above-ground parts of the plant. The toxic elements like Arsenic, Chromium, Cadmium, Nickel, Lead and Mercury etc. accumulate in the plants which hinder the growth and development of the plants. So, to correct the toxicity in plants Phytoremediation process is best. Phytoremediation process is used to accumulate the heavy metals or to degrade the toxic molecules of heavy metals into a non-toxic form. Various hyperaccumulator plants are used to extract the heavy metals because they do not have any toxic effects and can tolerate the toxic effect of the contaminants. The phytoremediation process is very important for agriculture because it is used for the degradation of toxic effluents which cleans the soil, water and plants so that the plants can easily grow. Along with this process Mycoremediation and Phytomining are also very beneficial because these processes also help in the extraction of heavy metals from the environment as well as funguses are used for their removal and the normal growth and development of the plants occurs which provides better yield.
Phytoremediation is a process which effectively uses plants as a tool to remove, detoxify or immobilize contaminants. It has been an eco-friendly and cost-effective technique to clean contaminated environments. The contaminants from various sources have caused an irreversible damage to all the biotic factors in the biosphere. Bioremediation has become an indispensable strategy in reclaiming or rehabilitating the environment that was damaged by the contaminants. The process of bioremediation has been extensively used for the past few decades to neutralize toxic contaminants, but the results have not been satisfactory due to the lack of cost-effectiveness, production of byproducts that are toxic and requirement of large landscape. Phytoremediation helps in treating chemical pollutants on two broad categories namely, emerging organic pollutants (EOPs) and emerging inorganic pollutants (EIOPs) under in situ conditions. The EOPs are produced from pharmaceutical, chemical and synthetic polymer industries, which have potential to pollute water and soil environments. Similarly, EIOPs are generated during mining operations, transportations and industries involved in urban development. Among the EIOPs, it has been noticed that there is pollution due to heavy metals, radioactive waste production and electronic waste in urban centers. Moreover, in recent times phytoremediation has been recognized as a feasible method to treat biological contaminants. Since remediation of soil and water is very important to preserve natural habitats and ecosystems, it is necessary to devise new strategies in using plants as a tool for remediation. In this review, we focus on recent advancements in phytoremediation strategies that could be utilized to mitigate the adverse effects of emerging contaminants without affecting the environment.
Radioactivity is a natural phenomenon and sources of radiation are typical features of some elements in the environment. Radiation and radioactive substances have many beneficial applications, ranging from power generation to uses in medicine, industry, and agriculture. The world is undergoing rapid developments where government administrators and people are giving emphasis to sustainable energy sources without pollution. Being a clean source of energy, nuclear energy is a preferable option to meet the energy requirements in different sectors and it does not contribute to greenhouse gases that contaminate our environment. The radioactive materials, which are, usually the by-products of the nuclear energy generation and other applications of nuclear fission, research, and medicine are commonly referred to as the radioactive wastes. Radioactive waste (or nuclear waste) is a material deemed no longer useful that has been contaminated by or contains radionuclides. Radionuclides are unstable atoms of an element that decay, or disintegrate spontaneously, emitting energy in the form of radiation. There are approximately 5000 natural and artificial radionuclides that have been identified, each with a different half-life. Radioactive wastes are generated during nuclear fuel cycle operation, production, and application of radioisotope in medicine, industry, research, and agriculture, and as a by-product of natural resource exploitation, which includes mining and processing of ores, combustion of fossil fuels, or production of natural gas and oil. Waste from nuclear weapons and reprocessing units usually contain alpha-emitting actinides such as Pu-239, which is a fissile material used in explosives, high specific activity material Pu-238 or Po, ³H, and Am-241. Medical wastes generally contain beta particles and gamma ray emitters varying from Y-90, I-131, Sr-89, Ir-192, Co-60, Cs-137, and few other isotopes that are used for medical applications. Naturally occurring radioactive material (NORM) includes all radioactive elements found in the environment. Long-lived radioactive elements such as U, Th, and K and their decay products viz. Ra and Rn are examples of NORM. These elements have always been present in the Earth’s crust and are concentrated in some areas, such as uranium ore builds which may be mined. The coal industry, oil and gas industry, metal mining and smelting, mineral sands, fertilizers industry, building industry are few activities that generally contain NORM. The quantum of radioactive waste in a country is dependent upon the scale of applications and range of activities associated with nuclear and radioactive mineral utilization. If not handled properly, radioactive wastes are deleterious to most forms of life as well as to the environment. The radioactive elements (radionuclides) cannot be destroyed by any known chemical or mechanical process. Their ultimate destruction is through radio-decay as stable isotopes or by nuclear transmutation by bombardment with atomic particles. Consequently, radioactive waste management consists of controlling and reducing the radioactive releases to tolerable levels. Removal of radionuclides from effluents and solid wastes is done by concentrating them into a form which can be stored or disposed of in a manner that they do not appear in hazardous concentrations in an ecosystem. Various international regulatory bodies like International Atomic Energy Agency and other government regulatory agencies are in action in order to protect the human health and environment by ensuring the safe use of nuclear energy.
Small experimental wetlands, with contrasting up- and downflow (vertical) hydraulic formats and colonized by Schoenoplectus validus, were supplied with increasing volumes and concentrations of nitrogen-rich, primary, settled wastewater until apparently overloaded. Loads reached six times that reported in the literature to have been successfully treated in trench systems, but in all treatments plant uptake was responsible for more than 90% of the nitrogen removal. This was despite marked oxygenation of the gravel substratum by plant roots, which is usually reported to enhance nitrogen loss by promoting microbial nitrification/denitrification. Unplanted gravel systems were inefficient and rapidly became overloaded. Artificial wetlands cannot be equated to conventional activated sludge or trickling filter systems as has been suggested in the literature. A greater emphasis on proper mass balance studies and the role of aquatic plants is needed if a predictive understanding of wetland wastewater treatment is to be developed.
In this work, chromium, copper, nickel, cadmium were selected as a model for metal contamination. This selection is based on the fact that these metals are discharged in many of the industries such as electroplating, detergents, oil refining and others. The isolation of bacteria resistant to different metal ions was done by using mixed industrial and domestic wastewater from the western station of sewage treatment plant in Alexandria. Iron limiting Casamino acid media is used in this study, since it can induce the production of fluorescent siderofores of the Pseudomonas species. Eighteen colonies were selected and purified as single colonies. The preliminary observation and the biochemical identification of these isolates indicated that the selected isolates are belonging to Pseudomonas species. Screening of the bacterial isolates for metal resistance against Cr(VI), Cu(II), Cd(II) and Ni(II) was done by the use of MIC and MTC (Maximum tolerable concentrations). Different metal concentrations were used throughout the screening to select bacterial isolates capable to grow and resist the metal toxicity. The optimum pH of metal precipitation was around 6. Whereas the optimum growth pH for Cr and Ni resistant strains was 5.5, while was 6 for Cu and Cd resistant strains.
Certain plants can concentrate essential and non-essential heavy metals in their roots and shoots to levels far exceeding those present in the soil. Metal-accumulating plant species are invariably restricted to metalliferous soils found in different regions around the world. The mechanisms of metal accumulation, which involve extracellular and intracellular metal chelation, precipitation, compartmentalization and translocation in the vascular system, are poorly understood. Interest in these mechanisms has led to the development of phytoremediation—a new technology to use plants to clean up soil and water contaminated with heavy metals.
Biosorption experiments for Cr(VI), Cu(II), Cd(II) and Ni(II) were investigated in this study using nonliving biomass of different Pseudomonas species. The applicability of the Langmuir and Freundlich models for the different biosorbent was tested. The coefficient of determination (R2) of both models were mostly greater than 0.9. In case of Ni(II) and Cu(II), their coefficients were found to be close to one. This indicates that both models adequately describe the experimental data of the biosorption of these metals. The maximum adsorption capacity was found to be the highest for Ni followed by Cd(II), Cu(II) and Cr(VI). Whereas the Freundlich constant k in case of Cd(II) was found to be greater than the other metals. Maximum Cr(VI) removal reached around 38% and its removal increased with the increase of Cr(VI) influent. Cu(II) removal was at its maximum value in presence of Cr(VI) as a binary metal, which reached 93% of its influent concentration. Concerning to Cd(II) and Ni(II) similar removal ratios were obtained, since it was ranged between 35 to 88% and their maximum removal were obtained in the case of individual Cd(II) and Ni(II).
With more than a decade of research behind them, technology developers are getting plants into the field to clean up metal-contaminated soil. Myrna Watanabe reports on these new companies and continuing efforts to find or breed 'hyperaccumulators'.
Interest in the use of organisms specifically propagated for their metal accumulating properties has continued. This includes not only the use of microorganisms as sorbents, but also the development of microbial populations that are able to grow in the presence of, and at the same time accumulate, heavy metals. An important consideration for the practical utilization of microorganisms for the accumulation/separation/recovery of metals which is the amount of metal that can be accumulated by the cell mass. The amounts of metals which microbial cells can accumulate vary from a few micrograms per gram of cells to several percent of the dry cell weight. The review presents several examples where substantial amounts of certain metals have been observed to be accumulated.
Artificial wetlands have been shown to have potential for treating wastewaters. An experimental artificial wetland is described together with a mass balance method for quantifying system performance, major nutrient storage components and nutrient removal mechanisms. The experimental systems were capable of a high level of performance. Percentage load removals for chemical oxygen demand, total nitrogen and total phosphorus were 86, 95 and 99%, respectively. Plant biomass was found to be the major nutrient storage compartment with plant nutrient uptake being the major removal mechanism. It was found that overall system performance could be described by a simple first order, steady state model. System design and hydrology were considered important factors in determining treatment performance. Designs must maximize wastewater-rootzone contact. The experimental systems used an upflow hydraulic format to achieve this design objective.
This review presents the status of phytoremediation technologies with particular emphasis on phytoextraction of soil heavy metal contamination. Unlike organic compounds, metals cannot be degraded, and cleanup usually requires their removal. Most of the conventional remedial technologies are expensive and inhibit the soil fertility; this subsequently causes negative impacts on the ecosystem. Phytoremediation is a cost effective, environmental friendly, aesthetically pleasing approach most suitable for developing countries. Despite this potential, phytoremediation is yet to become a commercially available technology in India. This paper reports about the mobility, bioavaliability and plant response to presence of soil heavy metals. It classifies the plants according to phytoextraction mechanism and discusses the pathway of metal in plants. Various techniques to enhance phytoextraction and utilization of by-products have been elaborated. Since lot of biomass is produced during this process, it needs proper disposal and management. It also gives an insight into the work done by authors, which focuses on high biomass extractor plants. High biomas weeds were selected to restrict the passage of contaminants into the food chain by selecting non-edible, disease resistant and tolerant plants, which can provide renewable energy. Thus making phytoextraction more viable for present utilization. Keywords. heavy metals, phytoextraction, hyperaccumulator, indicator, excluder species
Hybrid poplar trees can uptake, hydrolyze, and dealkylate atrazine to less toxic metabolites. In whole plant studies, the parent compound atrazine and 14C ring-labeled metabolites were extracted from poplar tissues and analyzed via high-pressure liquid chromatography (HPLC) with UV and radiochromatographic detectors in series. The concurrent separation and identification of these metabolites has not been previously reported in higher plants for phytoremediation applications. Unidentified metabolites were also detected. Metabolism of atrazine occurred in poplar roots, stems, and leaves and became more complete with increased residence time in tissues. In poplar cuttings exposed to atrazine for 50 days, the parent compound comprised only 21% of the 14C label in the leaves, while it constituted 59% of 14C activity remaining in the soil. After 80 days, the parent compound remaining in the leaves had decreased to only 10% of the 14C label recovered in the leaves. Preferred metabolic pathways were suggested by relative rates of reaction, and a mathematical model was developed to estimate rate constants for the proposed degradation mechanism. This research provides evidence for vegetative detoxification of contaminants and suggests that phytoremediation of atrazine-contaminated soils may be feasible.
Mycelial wastes of Rhizopus arrhizus, used in fermentation industries to produce lipases, were studied for their ability to absorb various heavy metal ions (Ni, Zn, Cd and Pb). Chelation of all these ions occurs by a chemical, equilibrated and saturatable mechanism, following the Langmuir adsorption model. Data transformation allowed us to calculate maximum uptake and dissociation constants of the sorption reaction. We also investigated the influence of pH on metal accumulation. Sorption capacity variations between different biosorbent types (Rhizopus, Mucor, Penicillium, and Aspergillus), could be related to their acidity. pH neutralisation during the sorption reaction considerably enhanced zinc chelation (up to 56 mg/g). Previous NaOH treatment of mycelial wastes also increased their capacity for metal sorption. We report R. arrhizus metal uptake curves versus pH, using a pH-stat system. Optimal adsorption was achieved at neutral pH for nickel and zinc, pH 5.0 for lead, and inhibition of chelation was observed when the pH decreased. These results illustrate the importance of pH during the adsorption process, indicating a competitive mechanism for chelation between heavy metal ions and protons at cell wall adsorption sites.
Biosorption of Th4+ and UO
2
2+
ions, both separately and in mixed equimolar ratio, was carried out using nitrate-buffered solutions of the cations at pH 1 in the presence of 5%w/w non-proliferative cell suspensions of Mycobacterium smegmatis. At equilibrium following a 3 h treatment, specific adsorption for 2 mM Th and U was, respectively, 102 and 115 mol g–1 dry biomass for individual solutions and 102 and 42 mol g–1 for the mixed 2/2 mM solution. Desorption studies of the cation-loaded biomass preparations in aqueous media and in soilbacterial suspensions within the pH range <1 to 11 showed that leaching of throium was generally less than 1% at pH 1–11 after 7 d, whereas uranium was leached to the extent of 2% at pH 1 and up to 10% under the same conditions in Th–U mixtures.
Impact of International Trade and Multinational Corporations on the Environment and Sustainable Livelihoods of Rural Women in Akwa-Ibom State, Niger Delta Region, Nigeria. Available at: http://www.gdnet.org An Overview of Phytoremediation of Lead and Mercury
- C Hassan
- J Olawoye
- K Nnadozie
Hassan C, Olawoye J, Nnadozie K (2002). Impact of International Trade
and Multinational Corporations on the Environment and Sustainable
Livelihoods of Rural Women in Akwa-Ibom State, Niger Delta Region,
Nigeria. Available at: http://www.gdnet.org/pdf/2002AwardsMe-
dalsWinners/OutstandingResearchDevelopment/comfort
Henry JR (2000). An Overview of Phytoremediation of Lead and
Mercury. NNEMS Report. Washington, D.C, Pp. 3-9.
Oil: A life cycle analysis of its health and environmental impacts. Published by The Center for Health and the Global Environment Harvard Medical School, 333 Longwood Ave
- S Borasin
- S Foster
- K Jobarteh
- N Link
- J Miranda
- E Pomeranse
- J Rabke-Verani
- D Reyes
- J Selber
- S Sodha
- P Somaia
Borasin S, Foster S, Jobarteh K, Link N, Miranda J, Pomeranse E,
Rabke-Verani J, Reyes D, Selber J, Sodha S, Somaia P (2002). In:
Epstein PR Selber J (Eds.) Oil: A life cycle analysis of its health and
environmental impacts. Published by The Center for Health and the
Global Environment Harvard Medical School, 333 Longwood Ave.
Suite 640, Boston, Mass. p. 02115.
Abstracts of Papers of the
- Sd Cunningham
- Jw Huang
- Chen J Berti
Cunningham SD, Huang JW, Chen J Berti WR (1996). Abstracts of
Papers of the American Chemical Society. 212: 87.
Phytoremediation. 7pp Available at: http://www.colorado Zinc distribution and excretion in the leaves of the Grey mangrove, Avicenia marina (Forsk.) Vierh
- J Kania
- M Hannigan
- Te Kujundzic
Kania J, Hannigan M, Kujundzic TE (2002). Phytoremediation. 7pp.
Available
at:
http://www.colorado.edu/MCEN/EnvTox/Phytoremedy.pdf
McFarlane GR, Burchett M (1999). Zinc distribution and excretion in the
leaves of the Grey mangrove, Avicenia marina (Forsk.) Vierh.
Environ. Exp. Bot. 41:167–175.
The Price of Oil Available at: http://www.hrw.org/rep- orts
HRW (1999). The Price of Oil. Available at: http://www.hrw.org/rep-
orts/1999/nigeria/index.htm Human Right Watch.
Potential of Phytoremediation, an emerging green technology In: Ecosystem Service and Sustainable Watershed Management in North China
- J Schwitzguébel
Schwitzguébel J (2000). Potential of Phytoremediation, an emerging
green technology. In: Ecosystem Service and Sustainable Watershed
Management in North China. Proceedings of International Conference, Beijing, P.R. China, August 23-25, 2000. p. 5.
Wetland vegetation Constructed wetlands for wastewater treatment
- Gr Guntensbergen
- F Stearns
- Ja Kadlec
Guntensbergen GR, Stearns F, Kadlec JA (1989). Wetland vegetation.
In: Hammer DA (Ed.) Constructed wetlands for wastewater treatment.
Lewis publishers, Chelsea, Michigan, pp.73-88.
Mangrove wetlands Southern Forested Wetlands
- Rr Twilley
- Mg Messina
- Wh Conner
Twilley RR (1998). Mangrove wetlands. In: Messina MG, Conner WH,
(Eds.) Southern Forested Wetlands. Ecology and Management. Boca
Raton, Florida: Lewis Publishers. pp. 445 -473.