scholarly journals Contribution of Nano-Zero-Valent Iron and Arbuscular Mycorrhizal Fungi to Phytoremediation of Heavy Metal-Contaminated Soil

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1264
Author(s):  
Peng Cheng ◽  
Shuqi Zhang ◽  
Quanlong Wang ◽  
Xueying Feng ◽  
Shuwu Zhang ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Sweet Sorghum ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Zero Valent Iron ◽  
X Ray ◽  
Metal Immobilization ◽  
Heavy Metal Immobilization ◽  
Nano Zero Valent Iron

Soil pollution with heavy metals has attracted increasing concern, which calls for the development of new remediation strategies. The combination of physical, chemical, and biological techniques can achieve more efficient remediation. However, few studies have focused on whether nanomaterials and beneficial microbes can be jointly used to facilitate phytoremediation. Therefore, we studied the role of nano-zero-valent iron (nZVI) and arbuscular mycorrhizal (AM) fungi in the phytoremediation of an acidic soil polluted with Cd, Pb and Zn, using sweet sorghum. X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), and mapping analyses were conducted to explore the mechanisms of metal immobilization by nZVI. The results showed that although both bare nZVI (B-nZVI) and starch-stabilized nZVI (S-nZVI) inhibited root mycorrhizal colonization, Acaulospora mellea ZZ successfully colonized the plant roots. AM inoculation significantly reduced the concentrations of DTPA-Cd, -Pb, and -Zn in soil, and the concentrations of Cd, Pb, and Zn in plants, indicating that AM fungi substantially facilitated heavy metal immobilization. Both B-nZVI and S-nZVI, ranging from 50 mg/kg to 1000 mg/kg, did not impede plant growth, and generally enhanced the phytoextraction of heavy metals. XRD, EDS and mapping analyses showed that S-nZVI was more susceptible to oxidation than B-nZVI, and thus had more effective immobilization effects on heavy metals. Low concentrations of nZVI (e.g., 100 mg/kg) and AM inoculation had synergistic effects on heavy metal immobilization, reducing the concentrations of Pb and Cd in roots and enhancing root Zn accumulation. In conclusion, our results showed that AM inoculation was effective in immobilizing heavy metals, whereas nZVI had a low phytotoxicity, and they could jointly contribute to the phytoremediation of heavy metal-contaminated soils with sweet sorghum.

scholarly journals Effects of Soil Amendments on Heavy Metal Immobilization and Accumulation by Maize Grown in a Multiple-Metal-Contaminated Soil and Their Potential for Safe Crop Production

Toxics ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 102
Author(s):  
Fayuan Wang ◽  
Shuqi Zhang ◽  
Peng Cheng ◽  
Shuwu Zhang ◽  
Yuhuan Sun
Keyword(s):  
Heavy Metal ◽  
Plant Growth ◽  
Contaminated Soil ◽  
Crop Production ◽  
Metal Uptake ◽  
Soil Amendments ◽  
Heavy Metal Uptake ◽  
X Ray ◽  
Metal Immobilization ◽  
Heavy Metal Immobilization

Soil amendments have been proposed for immobilizing metallic contaminants, thus reducing their uptake by plants. For the safe production of crops in contaminated soil, there is a need to select suitable amendments that can mitigate heavy metal uptake and enhance crop yield. The present experiment compared the effects of three amendments, hydroxyapatite (HAP), organic manure (OM), and biochar (BC), on plant growth and heavy metal accumulation by maize in an acidic soil contaminated with Cd, Pb, and Zn, and their potential for safe crop production. Toxicity characteristic leaching procedure (TCLP) tests, energy dispersive X-ray spectroscopy (EDS) analysis, and X-ray diffraction (XRD) analysis were used to evaluate the effectiveness and mechanisms of heavy metal immobilization by the amendments. The results showed that shoot and root biomass was significantly increased by HAP and 1% OM, with an order of 1% HAP > 0.1% HAP > 1% OM, but not changed by 0.1% OM and BC (0.1% and 1%). HAP significantly decreased Cd, Pb, and Zn concentrations in both shoots and roots, and the effects were more pronounced at the higher doses. OM decreased the shoot Cd and Pb concentrations and root Zn concentrations, but only 1% OM decreased the shoot Zn and root Pb concentrations. BC decreased the shoot Cd and Pb concentrations, but decreased the shoot Zn and root Pb concentrations only at 1%. HAP decreased the translocation factors (TFs) of Cd, Pb, and Zn (except at the 0.1% dose). OM and BC decreased the TFs of Cd and Zn, respectively, at the 1% dose but showed no significant effects in other cases. Overall, plant P, K, Fe, and Cu nutrition was improved by HAP and 1% OM, but not by 0.1 OM and BC. Soil pH was significantly increased by HAP, 1% OM, and 1% BC, following an order of 1% HAP > 1% OM > 0.1% HAP > 1% BC. The TCLP levels for Cd, Pb, and Zn were significantly reduced by HAP, which can be partly attributed to its liming effects and the formation of sparingly soluble Cd-, Pb-, and Zn-P-containing minerals in the HAP-amended soils. To some extent, all the amendments positively influenced plant and soil traits, but HAP was the optimal one for stabilizing heavy metals, reducing heavy metal uptake, and promoting plant growth in the contaminated soil, suggesting its potential for safe crop production.

scholarly journals Diversity of Arbuscular Mycorrhizal Fungus Populations in Heavy-Metal-Contaminated Soils

1999 ◽  
Vol 65 (2) ◽  
pp. 718-723 ◽  
Author(s):  
C. Del Val ◽  
J. M. Barea ◽  
C. Azcón-Aguilar
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Contaminated Soils ◽  
Agricultural Soils ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Wiener Index ◽  
Life Cycles ◽  
The European Union

ABSTRACT High concentrations of heavy metals have been shown to adversely affect the size, diversity, and activity of microbial populations in soil. The aim of this work was to determine how the diversity of arbuscular mycorrhizal (AM) fungi is affected by the addition of sewage-amended sludge containing heavy metals in a long-term experiment. Due to the reduced number of indigenous AM fungal (AMF) propagules in the experimental soils, several host plants with different life cycles were used to multiply indigenous fungi. Six AMF ecotypes were found in the experimental soils, showing consistent differences with regard to their tolerance to the presence of heavy metals. AMF ecotypes ranged from very sensitive to the presence of metals to relatively tolerant to high rates of heavy metals in soil. Total AMF spore numbers decreased with increasing amounts of heavy metals in the soil. However, species richness and diversity as measured by the Shannon-Wiener index increased in soils receiving intermediate rates of sludge contamination but decreased in soils receiving the highest rate of heavy-metal-contaminated sludge. Relative densities of most AMF species were also significantly influenced by soil treatments. Host plant species exerted a selective influence on AMF population size and diversity. We conclude based on the results of this study that size and diversity of AMF populations were modified in metal-polluted soils, even in those with metal concentrations that were below the upper limits accepted by the European Union for agricultural soils.

Comparison of heavy metal immobilization in contaminated soils amended with peat moss and peat moss-derived biochar

2016 ◽  
Vol 18 (4) ◽  
pp. 514-520 ◽  
Author(s):  
Jin Hee Park ◽  
Seul-Ji Lee ◽  
Myoung-Eun Lee ◽  
Jae Woo Chung
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Contaminated Soils ◽  
Soil Amendments ◽  
Peat Moss ◽  
Metal Immobilization ◽  
Heavy Metal Immobilization

Soil amendments showed contradictory results in heavy metal immobilization. Peat moss increased mobility and bioavailability of heavy metals in soil while peat moss-derived biochar decreased both through the coordination of metal electrons to CC bonds of the biochar.

scholarly journals Arbuscular Mycorrhizal Fungi (AMF) as Buffer for Heavy Metals Phytoextraction by Cucurbita maxima Duch. Grown on Crude Oil Contaminated Soil

2018 ◽  
Vol 3 ◽  
pp. 1-12
Author(s):  
Okon G. Okon ◽  
J.E. Okon ◽  
G.D.O. Eneh
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Crude Oil ◽  
Mycorrhizal Fungi ◽  
Growth Parameters ◽  
Chemical Properties ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Heavy Metal Accumulation ◽  
Cucurbita Maxima

This study evaluated the influence of Arbuscular Mycorrhizal (Rhizophagus irregularis) fungi inoculation (M) on the growth ofCucurbita maximaand as a buffer against phytoextraction of selected heavy metals (HM) (Zn, Cu, Cr, Cd and Pb) from a soil contaminated with crude oil (C). The experiment was set up using four soil treatments, each with three replicates C+ M-, C+ M+, C-M+ and C-M- (control without oil and inoculum). The shoot length, petiole length, number of nodes, leaf area and percentage germination ofC. maximawere significantly (p=0.05) reduced in uninoculated crude oil treatment (C+ M-), unpolluted mycorrhizal inoculated treatments (C-M+) showed remarkable response in growth parameters above the control (C-M-), while the polluted and inoculated treatment (C+ M+) showed significant (p=0.05) increase in growth parameters when compared to the polluted uninoculated treatment (C+ M-). Heavy metals analysis revealed a significant (p=0.05) difference in the heavy metal accumulation ofC. maxima. The heavy metals analyzed in this study are present thus inC. maxima; Zn>Cu>Cr>Pb>Cd. Crude oil polluted uninoculated treatment (C+ M-) recorded the highest concentrations of heavy metals than crude oil polluted inoculated (R. irregularis) treatment (C+ M+). Mycorrhizal inoculated unpolluted treatment (C-M+) and unpolluted uninoculated treatment (C-M-) indicated the lowest heavy metal concentrations. Inoculation withR. irregularissignificantly (p=0.05) reduced heavy metals uptake byC. maximaas observed in this study. Also, the negative effect of crude oil on AMF root colonization ofC. maximabyR. irregulariswas observed in polluted and inoculated treatment. HM often accumulate in the top layer of soil, therefore, are available for uptake by plants via roots, which is a major entry point of HM that ultimately affects different physiological processes. AM fungi can impinge on the chemical properties of heavy metals in the soil, their absorption by the host plant, and their allocation to different plant parts, affecting plant growth and the bioremediation process, thus making the AM fungi a suitable buffer for mitigating heavy metal stress onC. maxima.

scholarly journals Heavy-Metal Stress and Developmental Patterns of Arbuscular Mycorrhizal Fungi

2004 ◽  
Vol 70 (11) ◽  
pp. 6643-6649 ◽  
Author(s):  
Teresa E. Pawlowska ◽  
Iris Charvat
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Spore Germination ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Metal Stress ◽  
Soil Conditions ◽  
Global Changes ◽  
Extraradical Mycelium ◽  
Metal Concentrations

ABSTRACT The rate of global deposition of Cd, Pb, and Zn has decreased over the past few decades, but heavy metals already in the soil may be mobilized by local and global changes in soil conditions and exert toxic effects on soil microorganisms. We examined in vitro effects of Cd, Pb, and Zn on critical life stages in metal-sensitive ecotypes of arbuscular mycorrhizal (AM) fungi, including spore germination, presymbiotic hyphal extension, presymbiotic sporulation, symbiotic extraradical mycelium expansion, and symbiotic sporulation. Despite long-term culturing under the same low-metal conditions, two species, Glomus etunicatum and Glomus intraradices, had different levels of sensitivity to metal stress. G. etunicatum was more sensitive to all three metals than was G. intraradices. A unique response of increased presymbiotic hyphal extension occurred in G. intraradices exposed to Cd and Pb. Presymbiotic hyphae of G. intraradices formed presymbiotic spores, whose initiation was more affected by heavy metals than was presymbiotic hyphal extension. In G. intraradices grown in compartmentalized habitats with only a portion of the extraradical mycelium exposed to metal stress, inhibitory effects of elevated metal concentrations on symbiotic mycelial expansion and symbiotic sporulation were limited to the metal-enriched compartment. Symbiotic sporulation was more sensitive to metal exposure than symbiotic mycelium expansion. Patterns exhibited by G. intraradices spore germination, presymbiotic hyphal extension, symbiotic extraradical mycelium expansion, and sporulation under elevated metal concentrations suggest that AM fungi may be able to survive in heavy metal-contaminated environments by using a metal avoidance strategy.

A Review on the Immobilization of Heavy Metals with Geopolymers

2013 ◽  
Vol 634-638 ◽  
pp. 173-177
Author(s):  
Xi Ling Zhang ◽  
Ai Ling Yao ◽  
Lin Chen
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Room Temperature ◽  
Coal Fly Ash ◽  
Hydration Product ◽  
Existing Problems ◽  
Aluminosilicate Gel ◽  
Metal Immobilization ◽  
Heavy Metal Immobilization ◽  
Alkaline Activator

Geopolymers Are Attracting Great Interest from Mining and Energy Industries Alike, to Solve their Pressing Waste Disposal Problems. Geopolymers for Immobilization of Heavy Metal Consist of an Alkaline Activator and Cementing Components, such as Metakaolin, Coal Fly Ash, Slag, Etc., or a Combination of Two or More of them. its Main Hydration Product Is Aluminosilicate Gel at Room Temperature. Properly Designed Geopolymers Can Exhibit both Higher Strengths and Lower Leading than Portland Cement. the Exact Mechanism by which Heavy Metal Immobilization Occurs Is Not Fully Understood, and it Is Thought to Be Caused by Three Routes. this Paper Also Analyzes the Existing Problems in the Process on the Immobilization of Heavy Metal with Geopolymers Research, and its Development Is Prospected.

scholarly journals Combined Influence of Low-Grade Metakaolins and Natural Zeolite on Compressive Strength and Heavy Metal Adsorption of Geopolymers

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 486
Author(s):  
Alcina Johnson Sudagar ◽  
Slávka Andrejkovičová ◽  
Fernando Rocha ◽  
Carla Patinha ◽  
Maria R. Soares ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Compressive Strength ◽  
Natural Zeolite ◽  
Metal Adsorption ◽  
Low Grade ◽  
Heavy Metal Adsorption ◽  
Adsorption Model ◽  
X Ray ◽  
Adsorption Capacities

Metakaolins (MKs) prepared from low-grade kaolins located in the Alvarães (A) and Barqueiros (B) regions of Portugal were used as the aluminosilicate source to compare their effect on the compressive strength and heavy metal adsorption of geopolymers. Natural zeolite, an inexpensive, efficient adsorbent, was used as an additive in formulations to enhance geopolymers’ adsorption capacities and reduce MK utilization’s environmental footprint. Geopolymers were synthesized with the replacement of MK by zeolite up to 75 wt.% (A25, B25—25% MK 75% zeolite; A50, B50—50% MK 50% zeolite; A75, B75—75% MK 25% zeolite; A100, B100—100% MK). The molar ratios of SiO2/Al2O3 and Na2O/Al2O3 were kept at 1 to reduce the sodium silicate and sodium hydroxide environmental impact. Geopolymers’ crystallography was identified using X-ray diffraction analysis. The surface morphology was observed by scanning electron microscopy to understand the effect of zeolite incorporation. Chemical analysis using X-ray fluorescence spectroscopy and energy dispersive X-ray spectroscopy yielded information about the geopolymers’ Si/Al ratio. Compressive strength values of geopolymers obtained after 1, 14, and 28 days of curing indicate high strengths of geopolymers with 100% MK (A100—15.4 MPa; B100—32.46 MPa). Therefore, zeolite did not aid in the improvement of the compressive strength of both MK-based geopolymers. The heavy metal (Cd2+, Cr3+, Cu2+, Pb2+, and Zn2+) adsorption tests exhibit relatively higher adsorption capacities of Barqueiros MK-based geopolymers for all the heavy metals except Cd2+. Moreover, zeolite positively influenced divalent cations’ adsorption on the geopolymers produced from Barqueiros MK as B75 exhibits the highest adsorption capacities, but such an influence is not observed for Alvarães MK-based geopolymers. The general trend of adsorption of the heavy metals of both MK-based geopolymers is Pb2+ > Cd2+ > Cu2+ > Zn2+ > Cr3+ when fitted by the Langmuir isotherm adsorption model. The MK and zeolite characteristics influence geopolymers’ structure, strength, and adsorption capacities.

scholarly journals Improved heavy metal immobilization of compacted clay by cement treatment

Heliyon ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. e06917
Author(s):  
Chairat Teerawattanasuk ◽  
Panich Voottipruex ◽  
Suksun Horpibulsuk
Keyword(s):  
Heavy Metal ◽  
Compacted Clay ◽  
Metal Immobilization ◽  
Heavy Metal Immobilization ◽  
Cement Treatment

X-ray fluorescence spectrometric determination of heavy metals in selected rice samples sold on the Liberian market: a case study conducted in Paynesville City, Greater Monrovia

2020 ◽  
Vol 9 (3) ◽  
pp. 1
Author(s):  
McClain James ◽  
PAYE Plenseh Diana ◽  
N’debewillie Kokolo ◽  
CHEA Sampson K. P. ◽  
Kiazolu J. Boima
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Cancer Risk ◽  
Hazard Index ◽  
Rice Sample ◽  
X Ray ◽  
Total Cancer Risk ◽  
Total Cancer ◽  
Rice Consumption ◽  
The Mean

Background: Environmental pollution with toxic heavy metals can be lead to the possible contamination of rice. Rice is a staple food widely consumed in the urban and rural parts of Liberia daily. Rice is cultivated in approximately 113 countries and a fundamental source for energy and protein. Objective: The study assesses selected heavy metals (As, Pb, Cd, Se, and Cr) concentration in selected imported rice and traditionally grown rice and bulgur wheat in Liberia. Methods: Six grade of imported rice, Bulgar wheat, and traditionally grown rice were purchased from the Duport Road and Red-Light markets in Greater Monrovia and analyze using X-ray Fluorescence Spectrometer. All data were analyzed using XLSTAT, and data was used to calculate the risk factor of each rice sample. Results: The mean concentration of heavy metal found in the rice as follow: As, 1.31ppm; Cd, 9.42ppm; Cr. 12.3ppm; Se, 5.73ppm; and Pb, 1.75ppm. The estimated daily intakes (EDIs) were calculated in combination with the rice consumption data. The mean intakes of As, Cd, Cr, Se, and Pb through rice were estimated to be 1.32, 9.42. 12.4. 5.74, and 1.75 mg/kg BW/day. Chromium has the average estimated daily intake. The combined hazard index for the heavy metals in each sample and the total cancer risk for each sample contributed most significantly to a cancer risk of rice consumption during adult life expectancy.Conclusion: The selected heavy metal concentration from the rice sample was above the FAO/WHO reference Standard but was within the range of the contaminant level except for chromium, which is above the accepted range. However, the hazard index and the total cancer risk indicate a potential non-carcinogenic and carcinogenic risk.  

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