Response of CaCl2-extractable heavy metals, polychlorinated biphenyls, and microbial communities to biochar amendment in naturally contaminated soils

Heavy metal pollution is a serious environmental problem as it adversely affects crop production and human activity. In addition, the microbial community structure and composition are altered in heavy-metal-contaminated soils. In this study, using full-length 16S rRNA gene sequences obtained by a PacBio RS II system, we determined the microbial diversity and community structure in heavy-metal-contaminated soil. Furthermore, we investigated the microbial distribution, inferred their putative functional traits, and analyzed the environmental effects on the microbial compositions. The soil samples selected in this study were heavily and continuously contaminated with various heavy metals due to closed mines. We found that certain microorganisms (e.g., sulfur or iron oxidizers) play an important role in the biogeochemical cycle. Using phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) analysis, we predicted Kyoto Encyclopedia of Genes and Genomes (KEGG) functional categories from abundances of microbial communities and revealed a high proportion belonging to transport, energy metabolism, and xenobiotic degradation in the studied sites. In addition, through full-length analysis, Conexibacter-like sequences, commonly identified by environmental metagenomics among the rare biosphere, were detected. In addition to microbial composition, we confirmed that environmental factors, including heavy metals, affect the microbial communities. Unexpectedly, among these environmental parameters, electrical conductivity (EC) might have more importance than other factors in a community description analysis.

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Analysis of microbial communities in heavy metals-contaminated soils using the metagenomic approach

Ecotoxicology ◽

10.1007/s10646-018-1981-x ◽

2018 ◽

Vol 27 (9) ◽

pp. 1281-1291 ◽

Cited By ~ 18

Author(s):

M. H. Hemmat-Jou ◽

A. A. Safari-Sinegani ◽

A. Mirzaie-Asl ◽

A. Tahmourespour

Keyword(s):

Heavy Metals ◽

Microbial Communities ◽

Contaminated Soils ◽

Metagenomic Approach

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Effects of Heavy Metals/Metalloids and Soil Properties on Microbial Communities in Farmland in the Vicinity of a Metals Smelter

Frontiers in Microbiology ◽

10.3389/fmicb.2021.707786 ◽

2021 ◽

Vol 12 ◽

Author(s):

Xuewu Hu ◽

Jianlei Wang ◽

Ying Lv ◽

Xingyu Liu ◽

Juan Zhong ◽

...

Keyword(s):

Heavy Metals ◽

Heavy Metal ◽

Soil Properties ◽

Microbial Communities ◽

Soil Ph ◽

Contaminated Soils ◽

High Throughput Sequencing ◽

Available Phosphorus ◽

Rrna Gene ◽

Multiple Heavy Metals

Microorganisms play a fundamental role in biogeochemical cycling and are highly sensitive to environmental factors, including the physiochemical properties of the soils and the concentrations of heavy metals/metalloids. In this study, high-throughput sequencing of the 16S rRNA gene was used to study the microbial communities of farmland soils in farmland in the vicinity of a lead–zinc smelter. Proteobacteria, Acidobacteria, Actinobacteria, Bacteroidetes, and Gemmatimonadetes were the predominant phyla in the sites of interest. Sphingomonas, Gemmatimonas, Lysobacter, Flavisolibacter, and Chitinophaga were heavy metal-/metalloid-tolerant microbial groups with potential for bioremediation of the heavy metal/metalloid contaminated soils. However, the bacterial diversity was different for the different sites. The contents of heavy metal/metalloid species and the soil properties were studied to evaluate the effect on the soil bacterial communities. The Mantel test revealed that soil pH, total cadmium (T-Cd), and available arsenic played a vital role in determining the structure of the microbial communities. Further, we analyzed statistically the heavy metals/metalloids and the soil properties, and the results revealed that the microbial richness and diversity were regulated mainly by the soil properties, which correlated positively with organic matter and available nitrogen, while available phosphorus and available potassium were negatively correlated. The functional annotation of the prokaryotic taxa (FAPROTAX) method was used to predict the function of the microbial communities. Chemoheterotrophy and airborne chemoheterotrophy of the main microbial community functions were inhibited by soil pH and the heavy metals/metalloids, except in the case of available lead. Mantel tests revealed that T-Cd and available zinc were the dominant factors affecting the functions of the microbial communities. Overall, the research indicated that in contaminated soils, the presence of multiple heavy metals/metalloids, and the soil properties synergistically shaped the structure and function of the microbial communities.

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Synergistic Effect of Rhamnolipid and Saponin Biosurfactants on Removal of Heavy Metals from Oil Contaminated Soils

Tenside Surfactants Detergents ◽

10.3139/113.110672 ◽

2020 ◽

Vol 57 (2) ◽

pp. 109-114

Author(s):

Amirhossein Dolatzadeh khiyavi ◽

Reza Hajimohammadi ◽

Hossein Amani ◽

Hadi Soltani

Keyword(s):

Heavy Metals ◽

Synergistic Effect ◽

Contaminated Soils ◽

Removal Of Heavy Metals

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Contamination of Heavy Metals, Polychlorinated Dibenzo-p-Dioxins/Furans and Dioxin-Like Polychlorinated Biphenyls in Wharf Roach Ligia spp. In Japanese Intertidal and Supratidal Zones

Applied Sciences ◽

10.3390/app11041856 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1856

Author(s):

Masato Honda ◽

Xuchun Qiu ◽

Suzanne Lydia Undap ◽

Takeshi Kimura ◽

Tsuguhide Hori ◽

...

Keyword(s):

Heavy Metals ◽

Polychlorinated Biphenyls ◽

Limit Of Detection ◽

Environmental Pollutants ◽

Dry Weight ◽

Polychlorinated Dibenzofurans ◽

Environmental Indicator ◽

Pollution Levels ◽

Copper Zinc ◽

Total Concentrations

We investigated the pollution levels of 6 heavy metals and 29 dioxins (polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (DL-PCBs)) in intertidal and supratidal zones by using wharf roaches (Ligia spp.) collected from 12 sampling sites on the coast of Northeast Japan from November 2011 to June 2012. The total concentrations of heavy metals ranged from 177 to 377 µg/g-dry weight (dw), and the predominant metals were copper, zinc, and aluminum. The order of the detected level of heavy metals was zinc > aluminum > copper > cadmium > lead > chromium, and this trend was similar to a previous report. The total toxic equivalent (TEQ) value of the PCDD/Fs ranged from less than the limit of detection (<LOD) to 2.33 pg-TEQ/g-dw, and the predominant congener was octachlorodibenzodioxin (<LOD to 110 pg/g-dw). Compared with PCDD/Fs, DL-PCBs were detected at a predominantly higher level (total TEQ value: 0.64–27.79 pg-TEQ/g-dw). Detected levels of dioxins, especially DL-PCBs in the wharf roach, were like those in the bivalves. These results indicate that the wharf roach could reflect heavy metals and dioxin pollution in the supratidal zones and is a suitable environmental indicator for these environmental pollutants. This is the first study to investigate heavy metals, PCDD/Fs, and DL-PCBs pollution in coastal isopods in Japan.

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Chemical Properties of Heavy Metal-Contaminated Soils from a Korean Military Shooting Range: Evaluation of Pb Sources Using Pb Isotope Ratios

Applied Sciences ◽

10.3390/app11157099 ◽

2021 ◽

Vol 11 (15) ◽

pp. 7099

Author(s):

Inkyeong Moon ◽

Honghyun Kim ◽

Sangjo Jeong ◽

Hyungjin Choi ◽

Jungtae Park ◽

...

Keyword(s):

Heavy Metals ◽

Heavy Metal ◽

Contaminated Soils ◽

Management Strategies ◽

Chemical Properties ◽

Heavy Metal Concentration ◽

Soil Samples ◽

Shooting Range ◽

Geochemical Properties ◽

Mineral Phases

In this study, the geochemical properties of heavy metal-contaminated soils from a Korean military shooting range were analyzed. The chemical behavior of heavy metals was determined by analyzing the soil pH, heavy metal concentration, mineral composition, and Pb isotopes. In total, 24 soil samples were collected from a Korean military shooting range. The soil samples consist of quartz, albite, microcline, muscovite/illite, kaolinite, chlorite, and calcite. Lead minerals, such as hydrocerussite and anglesite, which are indicative of a transformation into secondary mineral phases, were not observed. All soils were strongly contaminated with Pb with minor concentrations of Cu, Ni, Cd, and Zn. Arsenic was rarely detected. The obtained results are indicated that the soils from the shooting range are contaminated with heavy metals and have evidences of different degree of anthropogenic Pb sources. This study is crucial for the evaluation of heavy metal-contaminated soils in shooting ranges and their environmental effect as well as for the establishment of management strategies for the mitigation of environmental risks.

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Fractionation of Heavy Metals in Multi-Contaminated Soil Treated with Biochar Using the Sequential Extraction Procedure

Biomolecules ◽

10.3390/biom11030448 ◽

2021 ◽

Vol 11 (3) ◽

pp. 448

Author(s):

Mahrous Awad ◽

Zhongzhen Liu ◽

Milan Skalicky ◽

Eldessoky S. Dessoky ◽

Marian Brestic ◽

...

Keyword(s):

Heavy Metals ◽

Organic Matter ◽

Soil Organic Matter ◽

Soil Ph ◽

Contaminated Soil ◽

Contaminated Soils ◽

Extraction Procedure ◽

Sequential Fractionation ◽

Relationship Of ◽

The Relationship

Heavy metals (HMs) toxicity represents a global problem depending on the soil environment’s geochemical forms. Biochar addition safely reduces HMs mobile forms, thus, reducing their toxicity to plants. While several studies have shown that biochar could significantly stabilize HMs in contaminated soils, the study of the relationship of soil properties to potential mechanisms still needs further clarification; hence the importance of assessing a naturally contaminated soil amended, in this case with Paulownia biochar (PB) and Bamboo biochar (BB) to fractionate Pb, Cd, Zn, and Cu using short sequential fractionation plans. The relationship of soil pH and organic matter and its effect on the redistribution of these metals were estimated. The results indicated that the acid-soluble metals decreased while the fraction bound to organic matter increased compared to untreated pots. The increase in the organic matter metal-bound was mostly at the expense of the decrease in the acid extractable and Fe/Mn bound ones. The highest application of PB increased the organically bound fraction of Pb, Cd, Zn, and Cu (62, 61, 34, and 61%, respectively), while the BB increased them (61, 49, 42, and 22%, respectively) over the control. Meanwhile, Fe/Mn oxides bound represents the large portion associated with zinc and copper. Concerning soil organic matter (SOM) and soil pH, as potential tools to reduce the risk of the target metals, a significant positive correlation was observed with acid-soluble extractable metal, while a negative correlation was obtained with organic matter-bound metal. The principal component analysis (PCA) shows that the total variance represents 89.7% for the TCPL-extractable and HMs forms and their relation to pH and SOM, which confirms the positive effect of the pH and SOM under PB and BB treatments on reducing the risk of the studied metals. The mobility and bioavailability of these metals and their geochemical forms widely varied according to pH, soil organic matter, biochar types, and application rates. As an environmentally friendly and economical material, biochar emphasizes its importance as a tool that makes the soil more suitable for safe cultivation in the short term and its long-term sustainability. This study proves that it reduces the mobility of HMs, their environmental risks and contributes to food safety. It also confirms that performing more controlled experiments, such as a pot, is a disciplined and effective way to assess the suitability of different types of biochar as soil modifications to restore HMs contaminated soil via controlling the mobilization of these minerals.

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Remediation of mercury-contaminated soils and sediments using biochar: a critical review

Biochar ◽

10.1007/s42773-021-00087-1 ◽

2021 ◽

Author(s):

Qian Yang ◽

Yongjie Wang ◽

Huan Zhong

Keyword(s):

Health Risks ◽

Contaminated Soils ◽

Functional Materials ◽

Redox Conditions ◽

Existing Problems ◽

Soils And Sediments ◽

Underlying Mechanisms ◽

Biochar Amendment

AbstractThe transformation of mercury (Hg) into the more toxic and bioaccumulative form methylmercury (MeHg) in soils and sediments can lead to the biomagnification of MeHg through the food chain, which poses ecological and health risks. In the last decade, biochar application, an in situ remediation technique, has been shown to be effective in mitigating the risks from Hg in soils and sediments. However, uncertainties associated with biochar use and its underlying mechanisms remain. Here, we summarize recent studies on the effects and advantages of biochar amendment related to Hg biogeochemistry and its bioavailability in soils and sediments and systematically analyze the progress made in understanding the underlying mechanisms responsible for reductions in Hg bioaccumulation. The existing literature indicates (1) that biochar application decreases the mobility of inorganic Hg in soils and sediments and (2) that biochar can reduce the bioavailability of MeHg and its accumulation in crops but has a complex effect on net MeHg production. In this review, two main mechanisms, a direct mechanism (e.g., Hg-biochar binding) and an indirect mechanism (e.g., biochar-impacted sulfur cycling and thus Hg-soil binding), that explain the reduction in Hg bioavailability by biochar amendment based on the interactions among biochar, soil and Hg under redox conditions are highlighted. Furthermore, the existing problems with the use of biochar to treat Hg-contaminated soils and sediments, such as the appropriate dose and the long-term effectiveness of biochar, are discussed. Further research involving laboratory tests and field applications is necessary to obtain a mechanistic understanding of the role of biochar in reducing Hg bioavailability in diverse soil types under varying redox conditions and to develop completely green and sustainable biochar-based functional materials for mitigating Hg-related health risks.

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Enhanced Electrokinetic Remediation for the Removal of Heavy Metals from Contaminated Soils

Applied Sciences ◽

10.3390/app11041799 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1799

Author(s):

Claudio Cameselle ◽

Susana Gouveia ◽

Adrian Cabo

Keyword(s):

Heavy Metals ◽

Citric Acid ◽

Organic Acids ◽

Contaminated Soils ◽

Electrokinetic Remediation ◽

Deionized Water ◽

Soil Specimen ◽

Removal Of Heavy Metals ◽

Ph Conditions ◽

Neutral Metal

The electrokinetic remediation of an agricultural soil contaminated with heavy metals was studied using organic acids as facilitating agents. The unenhanced electrokinetic treatment using deionized water as processing fluid did not show any significant mobilization and removal of heavy metals due to the low solubilization of metals and precipitation at high pH conditions close to the cathode. EDTA and citric acid 0.1 M were used as facilitating agents to favor the dissolution and transportation of metals. The organic acids were added to the catholyte and penetrated into the soil specimen by electromigration. EDTA formed negatively charged complexes. Citric acid formed neutral metal complexes in the soil pH conditions (pH = 2–4). Citric acid was much more effective in the dissolution and transportation out of the soil specimen of complexed metals. In order to enhance the removal of metals, the concentration of citric acid was increased up to 0.5 M, resulting in the removal of 78.7% of Cd, 78.6% of Co, 72.5% of Cu, 73.3% of Zn, 11.8% of Cr and 9.8% of Pb.

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Dynamic of Morphological and Physiological Parameters and Variation of Soil Characteristics during Miscanthus × giganteus Cultivation in the Diesel-Contaminated Land

Agronomy ◽

10.3390/agronomy11040798 ◽

2021 ◽

Vol 11 (4) ◽

pp. 798

Author(s):

Valentina Pidlisnyuk ◽

Andriy Herts ◽

Volodymyr Khomenchuk ◽

Aigerim Mamirova ◽

Oleksandr Kononchuk ◽

...

Keyword(s):

Contaminated Soil ◽

Contaminated Soils ◽

Soil Characteristics ◽

Physiological Parameters ◽

Wastewater Sludge ◽

Contaminated Land ◽

Miscanthus Giganteus ◽

Uncontaminated Soil ◽

Stems And Leaves ◽

Biochar Amendment

Miscanthus × giganteus (M. × giganteus) is a perspective plant produced on marginal and contaminated lands with biomass used for energy or bioproducts. In the current study, M. × giganteus development was tested in the diesel-contaminated soils (ranged from 250 mg kg−1 to 5000 mg kg−1) and the growth dynamic, leaves quantity, plants total area, number of harvested stems and leaves, SPAD and NPQt parameters were evaluated. Results showed a remarkable M. × giganteus growth in a selected interval of diesel-contaminated soil with sufficient harvested biomass. The amendment of soil by biochar 1 (produced from wastewater sludge) and biochar 2 (produced from a mixture of wood waste and biohumus) improved the crop’s morphological and physiological parameters. Biochar 1 stimulated the increase of the stems’ biomass, while biochar 2 increased the leaves biomass. The plants growing in the uncontaminated soil decreased the content of NO3, pH (KCl), P2O5 and increased the content of NH4. Photosynthesis parameters showed that incorporating biochar 1 and biochar 2 to the diesel-contaminated soil prolonged the plants’ vegetation, which was more potent for biochar 1. M. × giganteus utilization united with biochar amendment can be recommended to remediate diesel-contaminated land in concentration range 250–5000 mg kg−1.

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