Phytoremediation Of Pollutants Research Articles

Phytoremediation of pollutants in oil-contaminated soils by Alhagi camelorum: evaluation and modeling

Phytoremediation is a cost-effective and environmentally friendly method, offering a suitable alternative to chemical and physical approaches for the removal of pollutants from soil. This research explored the phytoremediation potential of Alhagi camelorum, a plant species, for total petroleum hydrocarbons (TPHs) and heavy metals (HMs), specifically lead (Pb), chromium (Cr), nickel (Ni), and cadmium (Cd), in oil-contaminated soil. A field-scale study spanning six months was conducted, involving the cultivation of A. camelorum seeds in a nursery and subsequent transplantation of seedlings onto prepared soil plots. Control plots, devoid of any plants, were also incorporated for comparison. Soil samples were analyzed throughout the study period using inductively coupled plasma-optical emission spectroscopy (ICP‒OES) for HMs and gas chromatography‒mass spectrometry (GC‒MS) for TPHs. The results showed that after six months, the average removal percentage was 53.6 ± 2.8% for TPHs and varying percentages observed for the HMs (Pb: 50 ± 2.1%, Cr: 47.6 ± 2.5%, Ni: 48.1 ± 1.6%, and Cd: 45.4 ± 3.5%). The upward trajectory in the population of heterotrophic bacteria and the level of microbial respiration, in contrast to the control plots, suggests that the presence of the plant plays a significant role in promoting soil microbial growth (P < 0.05). Moreover, kinetic rate models were examined to assess the rate of pollutant removal. The coefficient of determination consistently aligned with the first-order kinetic rate model for all the mentioned pollutants (R2 > 0.8). These results collectively suggest that phytoremediation employing A. camelorum can effectively reduce pollutants in oil-contaminated soils.

Antimicrobial activity of Pantanal macrophytes against multidrug resistant bacteria shows potential for improving nature-based solutions

The presence of macrophytes in constructed wetlands (CW) applied within the concept of nature-based solution (NBS) is crucial. Besides their role in the phytoremediation of pollutants, the cultivated plants, if properly selected, can also produce a range of bioactive compounds, including those with potential inhibitory effects against pathogenic bacteria. Bioactive compounds, such as flavonoids and ellagitannins, known for their remarkable antimicrobial properties, offer a sustainable solution to the global challenge of antibiotic resistance. In this study, we investigated macrophyte species adapted to the water variations in the Pantanal region (flood and dry seasons), focusing on those with both antimicrobial and ornamental potential, that could improve the ability of a CW system to treat greywater. Seven different macrophyte species were collected, cultivated, and evaluated for their antimicrobial activity (AA) against five standard bacterial strains and five multidrug-resistant clinical bacterial strains. Extracts from the leaf, stem, and root of Polygonum acuminatum showed the best AA against clinical multidrug-resistant strains of Staphylococcus aureus, Enterococcus faecium, and Escherichia coli, with minimum inhibitory concentration (MIC) values ranging from 78.13 to 312.5 µg.mL−1. Furthermore, the leaves of Ludwigia lagunae and P. acuminatum also showed considerable AA against standard strains of Enterococcus faecalis (MIC = 19.5 and 39.06 µg.mL−1, respectively) and Pseudomonas aeruginosa (MIC = 156.25 µg.mL−1 for both). High-Performance Liquid Chromatography with Ultraviolet and Mass Spectrometry analysis of these extracts identified important bioactive compounds, including flavonoids (quercetin 3-rhamnoside, hydropiperoside, quercetin 3-O-rutinoside, quercetin, myricetin 3-O-rhamnoside, kaempferol 3-O-rhamnoside, formononetin, and calycosin) and ellagitannins (3,3′4-tri-O-methylelagic acid, galloys-HHDP-glucose, and ellagic acid), along with other bioactive compounds. These results indicate that P. acuminatum and L. lagunae hold potential for application in CW owing to their antimicrobial property, local adaptability, and ornamental appeal.

Biochar; an effective factor in improving phytoremediation of metal(iod)s in polluted sites

Phytoremediation is one of the cheapest and most widely used technologies for stabilizing and extracting pollutants from contaminated sites. Recently, a variety of solutions, such as the use of different elements, compost, nanoparticles, microorganisms, etc., have been explored for improving and accelerating the phytoremediation process. Biochar has also gained attention for its affordability, abundance, ability to improve soil structure and plant morpho-physiology and biochemistry, lack of environmental hazards, etc. As a first step, this study aimed to provide an overview of biochar’s properties, and operation by identifying the method of production and examining the differences between different types of biochar. Following that, by examining various factors that pollute the environment, the influence of different types of biochar on phytoremediation efficiency was explored. Also, in this study, an attempt has been made to examine the effect of the combination of biochar with other factors in improving the phytoremediation of pollutants, as well as the use of the residues of phytoremediation for the production of biochar, so that future research can be planned based on the results obtained.

Evaluating the Potential of Mangrove Phytoremediation for Mitigating Coastal Water Eutrophication in Macao SAR: A Field and Mesocosm Study

Eutrophication due to anthropogenic nutrient inputs is a serious issue in many coastal and marine environments. Mangrove plants form unique intertidal forests at the edge of the land and sea, forming multifunctional ecosystems that provide an array of services, such as the phytoremediation of pollutants. The purpose of this study was to evaluate the levels of nutrients (PO43−, NO2−, NO3−, NH4+) in the coastal waters around Macao SAR, in areas with and without mangroves, in order to assess their phytoremediation potential. The work was reinforced through a mesocosm experiment with various treatments with and without mangroves. The results of the field investigations indicated a high degree of eutrophication in the coastal waters of Macao, with average values of 0.30 mg/L, 0.09 mg/L, 23.8 mg/L, and 0.36 mg/L of phosphate, nitrite, nitrate, and ammonium, respectively. There were no apparent significant differences in the levels of nutrients in areas with and without mangroves, which was most likely caused by the conditions during sampling as well as the density of the mangrove forest. The mesocosm experiments, however, revealed a clearer effect of the presence of mangroves (and sediments) in the degradation of nutrients. Therefore, it is highly recommended to plant more mangroves to help mitigate coastal water eutrophication in the area as a phytoremediation approach.

Duckweeds for Phytoremediation of Polluted Water.

Tiny aquatic plants from the Lemnaceae family, commonly known as duckweeds, are often regarded as detrimental to the environment because of their ability to quickly populate and cover the surfaces of bodies of water. Due to their rapid vegetative propagation, duckweeds have one of the fastest growth rates among flowering plants and can accumulate large amounts of biomass in relatively short time periods. Due to the high yield of valuable biomass and ease of harvest, duckweeds can be used as feedstock for biofuels, animal feed, and other applications. Thanks to their efficient absorption of nitrogen- and phosphate-containing pollutants, duckweeds play an important role in the restorative ecology of water reservoirs. Moreover, compared to other species, duckweed species and ecotypes demonstrate exceptionally high adaptivity to a variety of environmental factors; indeed, duckweeds remove and convert many contaminants, such as nitrogen, into plant biomass. The global distribution of duckweeds and their tolerance of ammonia, heavy metals, other pollutants, and stresses are the major factors highlighting their potential for use in purifying agricultural, municipal, and some industrial wastewater. In summary, duckweeds are a powerful tool for bioremediation that can reduce anthropogenic pollution in aquatic ecosystems and prevent water eutrophication in a simple, inexpensive ecologically friendly way. Here we review the potential for using duckweeds in phytoremediation of several major water pollutants: mineral nitrogen and phosphorus, various organic chemicals, and heavy metals.

Microscale Spatiotemporal Variation and Generation Mechanisms of Reactive Oxygen Species in the Rhizosphere of Ryegrass: Coupled Biotic-Abiotic Processes.

Reactive oxygen species (ROS) play key roles in soil biogeochemical processes, yet the occurrence and accumulation of ROS in the rhizosphere are poorly documented. Herein, we first developed a ROS-trapping membrane to in situ determine ROS in the ryegrass rhizosphere and then quantified the temporal and spatial variations of representative ROS (i.e., O2•─, H2O2, and •OH). Fluorescence imaging clearly visualized the production of ROS in the rhizosphere. Both O2•─ and H2O2 content increased first and then declined throughout the life cycle of ryegrass, while •OH concentration decreased continuously. Spatially, ROS contents remained at a relatively high level at 0-5 mm and then descended with increasing distance. The concentrations of ROS in different soils followed the order of black soil > latosol soil > yellow-brown soil > tier soil ∼ red soil. Analysis of soil properties suggested that both biotic factors (microbial community) and abiotic factors (Fe(II) and water-soluble phenols) played critical roles in ROS production. The combined processes, including Fe(II) and water-soluble phenol-mediated electron transfer, microbial community-driven extracellular O2•─ release, and Fe(II)/Fe(III) cycling, may be responsible for ROS production. These findings provide insights into ROS-associated rhizosphere effects and inspiration for the phytoremediation of pollutants and element cycling.

Phytoremediation of pollutants from wastewater: A concise review.

As there is a global water crisis facing the whole world, it is important to find alternative solutions to treat wastewater for reuse. Hence, plants have an effective role in removing pollutants from wastewater, which has been emphasized in this review article. Biological treatment of wastewater can be considered an eco-friendly and cost-effective process that depends on in the future. Living organisms, including plants, can remediate pollutants in wastewater, especially in agricultural fields, such as dyes, heavy metals, hydrocarbons, pharmaceuticals, and pesticides. This review discusses the different activities of plants in pollutant elimination from wastewater and sheds light on the utilization of plants in this scope. This review focuses on the remediation of the most common contaminants present in wastewater, which are difficult to the removal with microorganisms, such as bacteria, fungi, and algae. Moreover, it covers the major role of plants in wastewater treatment and the potential of phytoremediation as a possible solution for the global water crisis.

Potential of Cyperus alternifolius, Amaranthus retroflexus, Closia cristata and Bambusa vulgaris to phytoremediate emerging contaminants and phytodesalination; Insight to floating beds technology

The main aim of this study is to consider the potential of different aquatic and terrestrial plants (Cyperus alternifolius, Amaranthus retroflexus, Closia cristata and Bambusa vulgaris( for phytoremediation of pollutants and phytodesalination through floating bed system. In this study, when Cyperus alternifolius plants were exposed to atrazine) 20 mg L -1(, OPC-LD )20 mg L -1(, OPC-LD )50 mg L -1(, fluorine )3.5 mg L -1(, and 1-4 Dioxane )25 mg L -1(, in a mesocosm treatment floating bed system, the phytoremediation efficiencies were 91.28 ± 6.35%, 82.33 ± 2.51 %, 75.67 ± 3.05%, 62.28 ± 5.77% and 42.29 ± 2.27 % respectively. When Amaranthus retroflexus plants were exposed to metformin )20 and 50 mg L-1( and OCP-LD )20 and 50 mg L-1(, 63 ± 5.24 %, 58.4 ± 2.11%, 38 ± 1.73 %, and 29 ± 01 % of the pollutants were removed. In the case of Closia cristata, the most efficiency belonged to metformin with a concentration of 50 mg L-1 . The results showed that in water containing NaCl in a range of 1000 to 2000 mg L-1 , Bambusa vulgaris with an efficiency of about 32.62 ± 4.65 % is a good candidate for phytodesalination. Consequently, C. alternifolius, a fast-growing plant with a good ecological stability in polluted water, can absorb pollutants and remains healthy after the treatment period. It is a good candidate for phytoremediation in vegetated floating beds.

Mechanistic insights on plant root colonization by bacterial endophytes: a symbiotic relationship for sustainable agriculture

Plant–microbe and soil interactions are one of the oldest muse for multi-disciplinary researchers. Plant growth promoting microorganisms influence the host physiology by secreting regulatory chemical signals in the vicinity of plant roots and play a key role in the enhancement of plant growth and expansion. The present review deals with the in-depth understanding of steps involved in host tissues colonization by bacterial endophytes. The molecular insights of these events, particularly for endophytic bacteria, are poorly documented till date. The endophytic bacteria must coexist with the host plant and capable of colonizing the internal plant tissues without being recognized as a pathogen. A proper understanding of exchange of signals between the host plant and bacterial communities is required which may facilitate the development of new strategies to promote beneficial interactions between them. This knowledge can be instrumental in agricultural practices as well as for phytoremediation of pollutants. Keeping these facts in mind, the present review attempts to explore the systematic understanding of steps involved and molecular insights of plant colonization events by endophytic bacteria. We conclude that molecular mechanisms and factors affecting endophytic bacterial colonization deserve more research attention in order to exploit their beneficial aspects for sustainable agriculture and environment.

Use of Terrestrial Plants for Phytoremediation of Pollutants from Solutions

Contamination of water resources by emerging contaminants, radionuclides, heavy metals and nitrate is a critical problem that adversely affects the biotope. Constructed wetlands, as one of the least energy consuming methods have become an interesting option for wastewater treatment. In this study, terrestrial plants were used for phytoremediation of important pollutants from waste water. Therefore, uptake rates of cesium, metformin, arsenic and nitrate in hydroponic mesocosem constructed wetland were studied. When initial Cs concentrations were 2.35, 7.90 and 19.75 mg l−1 in mesocosem constructed wetland, 89.36 ± 0.42, 88.56 ± 0.19 and 84.72 ± 0.15% of cesium were remediated by Amaranthus chlorostachys plants. In the same cesium concentrations in mesocosem constructed wetland, 18.43 ± 2.76, 78.98 ± 0.25 and 89.35 ± 0.25% cesium found to be remediated by Calendula alata plants. When exposed to 20 and 50 mg l−1 metformin solutions 63 ± 14 and 58.4 ± 8.60% metformin were remediated by Amaranthus retroflexus plants. When exposed to 0.3 mg l−1 sodium arsenate solution, 85.5 and 93.1% of arsenic were remediated after 14 and 21 days by Vetiveria zizanioides. In the case that initial concentrations of nitrate in hydroponic mesocosem constructed wetland were 32.7, 40.08 and 47.37 mg l−1, 40.27, 26.64 and 70.02% of nitrate were removed, respectively, after 14 days.

Response of mangrove propagules to the presence of oil and hydrocarbon degrading bacteria during an experimental oil spill

The aim of this work was to investigate the effect of marine diesel oil on the development and survival of three different species of mangrove propagules with or without a hydrocarbon-degrading bacterial consortium and the possible use of propagules for the recovery of mangroves impacted by oil. The study was conducted in a greenhouse, near a mangrove from which we collected samples of sediments and propagules of Laguncularia racemosa , Avicennia schaueriana and Rhizophora mangle . The bacterial consortium comprised Bacillus spp., Rhizobium spp., Pseudomonas spp., Ochrobactrum spp. and Brevundimonas spp. After six months, L. racemosa and A. schaueriana only survived in control treatments and R. mangle showed the highest survival rates of the three species, indicating that different mangrove species do not respond uniformly to oil spills. Propagules of R. mangle are much more resistant and the hydrocarbon-degrading bacterial consortium we tested can be applied in the phytoremediation of pollutants.

Implications des communautés végétales péri-agricoles dans la dynamique environnementale des pollutions par les pesticides

Implications of field margin plant communities in the environmental dynamics of pesticides pollutions. Several types of regulations, at the European and national levels, advocate setting up vegetative buffer strips in order to control or prevent the contamination of ecosystems by agricultural pollutions. The specific implication of the plant communities that are part of the make-up of buffer zones will be assessed in the context of agriculture-linked pollutions by pesticides. The distribution of environmental contaminations involving pesticides and associated products shows that plant communities of vegetative buffer strips are confronted with chemical and xenobiotic stresses that show great fluctuations and complexity, with, among other characteristics, exposures to mixtures of low levels of pollutants. The physical and microbiological dimensions of plant action on the environmental dynamics of contaminating pesticides are well understood, but higher plants are also capable of efficient responses to chemical and xenobiotic stresses and of phytoremediation of pollutants. However, the direct phytoremediating roles of plants in vegetative buffer-zones have remained poorly appreciated, and the interferences that affect this capacity for phytoremediation are not fully understood either. It is therefore essential that integrative studies take into account the diversity of contaminants, the diversity of plant species that are used in buffer zones, their capacity to respond to organic xenobiotics under laboratory controlled conditions, and their ecophysiological behaviour under real field conditions. Such studies will be useful to optimize the depollution capacities of buffer zones in relation with the various modalities of contamination and combinations of pollutants.

Phytoremediation of soils contaminated by organic compounds: hype, hope and facts

Purpose The present opinion paper is focused on the phytoremediation of organic pollutants and is based on the lectures given by the author during the International Congress of Phytoremediation of Polluted Soils, held at Vigo, Spain, 29–30 July 2014. The aim of this position paper is (1) to highlight some progress made within the last few years (after the end of COST Action 859 in October 2009) in the phytoremediation of selected organic pollutants and (2) to suggest new research and approaches, which seem important and promising in the opinion of the author to make this environmentally friendly remediation technique more attractive and more successful.

In-Situ Phytoremediation of Pahs Contaminated Soils Following a Bioremediation Treatment

Phytoremediation of pollutants in soils is an emerging technology, using different soil-plant interaction properties. For organic pollutants, such as polycyclic aromatic hydrocarbons (PAHs), phytodegradation seems to be the most promising approach. It occurs mostly through an increase of the microbial activity in the plant rhizosphere, allowing the degradation of organic substances, a source of carbon for soil microbes. Despite a large amount of available data in the literature concerning laboratory and short term PAH phytodegradation experiments, no actual field application of such technique was previously carried out. In the present study, a soil from a former coking plant was used to evaluate the feasibility and the efficiency of PAH phytodegradation in the field during a three years trial and following a bioremediation treatment. Before the phytoremediation treatment, the soil was homogenized and split into six independent plots with no hydrological connections. On four of these plots, different types of common plant species were sowed: mixture of herbaceous species, short cut (P1), long cut (P2), ornamental plants (P3) and trees (P4). Natural vegetation was allowed to grow on the fifth plot (P5), and the last plot was weeded (P6). Each year, representative sampling of two soil horizons (0-50 and 50-100 cm) was carried out in each plot to characterize the evolution of PAHs concentration in soils and in soils solution obtained by lixiviation. Possible impact of the phytoremediation technique on ecosystems was evaluated using different eco- and genotoxicity tests both on the soil solid matrix and on the soil solution. For each soil horizon, comparable decrease of soil total PAHs concentrations were obtained for three plots, reaching a maximum value of 26% of the initial PAHs concentration. The decrease mostly concerned the 3 rings PAHs. The overall low decrease in PAHs content was linked to a drastic decrease in PAHs availability likely due to the bioremediation treatment. However, soil solutions concentration showed low values and no significant toxicity was characterized. The mixture of the herbaceous species seemed to be the most promising plants to be used in such procedure.