scholarly journals Bioremediation Capacity of Edaphic Cyanobacteria Nostoc linckia for Chromium in Association with Other Heavy-Metals-Contaminated Soils

Environments ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
Liliana Cepoi ◽  
Inga Zinicovscaia ◽  
Ana Valuta ◽  
Liviu Codreanu ◽  
Ludmila Rudi ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Contaminated Soils ◽  
Soil Removal ◽  
Soil Washing ◽  
Soil Surface ◽  
Anthropogenic Activity ◽  
Nostoc Linckia ◽  
High Level ◽  
Cu And Zn ◽  
Main Factor

Anthropogenic activity is the main factor contributing to soil pollution with various toxic metals, including Cr(VI), which dictates the need for decontamination. Often, the traditionally used remediation methods (soil removal, stabilization/solidification, physicochemical extraction, and soil washing) are not sufficiently efficient. Among gentle soil remediation, options can be considered. The aim of this study is to assess the ability of Nostoc linckia to remediate soils contaminated with Cr(VI) in association with other metals. Metal uptake by biomass was assessed using neutron activation analysis, while the components of Nostoc biomass were determined using specific methods. The capacity to accumulate chromium from the contaminated environment (Cr in association with Fe, Ni, Cu, and Zn) by the Nostoc linckia is kept at a high level for three generations of cyanobacterium, and the capacity to accumulate Fe, Ni, Cu, and Zn is growing over the cultivation cycles. The process of accumulation of heavy metals is associated with significant changes in the biochemical composition of Nostoc biomass. Due to the high bioaccumulation capacity and the specific growth mode with the formation of crusts on the soil surface, the edaphic cyanobacteria Nostoc linckia is an important candidate for the bioremediation of soil contaminated with chromium in association with other metals.

scholarly journals Effect of Soil Washing Solutions on Simultaneous Removal of Heavy Metals and Arsenic from Contaminated Soil

2020 ◽  
Vol 17 (9) ◽  
pp. 3133 ◽  
Author(s):  
Kanghee Cho ◽  
Eunji Myung ◽  
Hyunsoo Kim ◽  
Cheonyoung Park ◽  
Nagchoul Choi ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Sulfuric Acid ◽  
Phosphoric Acid ◽  
Contaminated Soil ◽  
Contaminated Soils ◽  
Soil Washing ◽  
Metal Extraction ◽  
Simultaneous Removal ◽  
Removal Of Heavy Metals ◽  
Removal Efficiencies

In this study, we investigated the feasibility of using a solution of sulfuric acid and phosphoric acid as an extraction method for soil-washing to remove Cu, Pb, Zn, and As from contaminated soil. We treated various soil particles, including seven fraction sizes, using sulfuric acid. In addition, to improve Cu, Pb, Zn, and As removal efficiencies, washing agents were compared through batch experiments. The results showed that each agent behaved differently when reacting with heavy metals (Cu, Pb, and Zn) and As. Sulfuric acid was more effective in extracting heavy metals than in extracting As. However, phosphoric acid was not effective in extracting heavy metals. Compared with each inorganic acid, As removal from soil by washing agents increased in the order of sulfuric acid (35.81%) < phosphoric acid (62.96%). Therefore, an enhanced mixture solution using sulfuric acid and phosphoric acid to simultaneously remove heavy metals and As from contaminated soils was investigated. Sulfuric acid at 0.6 M was adopted to combine with 0.6 M phosphoric acid to obtain the mixture solution (1:1) that was used to determine the effect for the simultaneous removal of both heavy metals and As from the contaminated soil. The removal efficiencies of As, Cu, Pb, and Zn were 70.5%, 79.6%, 80.1%, and 71.2%, respectively. The combination of sulfuric acid with phosphoric acid increased the overall As and heavy metal extraction efficiencies from the contaminated soil samples. With the combined effect of dissolving oxides and ion exchange under combined washings, the removal efficiencies of heavy metals and As were higher than those of single washings.

scholarly journals Heavy Metals in Contaminated Soils: A Review of Sources, Chemistry, Risks and Best Available Strategies for Remediation

ISRN Ecology ◽  
2011 ◽  
Vol 2011 ◽  
pp. 1-20 ◽  
Author(s):  
Raymond A. Wuana ◽  
Felix E. Okieimen
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Land Tenure ◽  
Contaminated Soils ◽  
Soil Washing ◽  
Land Resource ◽  
Land Use Pattern ◽  
Advantages And Disadvantages ◽  
Zinc Cadmium ◽  
Scale Down

Scattered literature is harnessed to critically review the possible sources, chemistry, potential biohazards and best available remedial strategies for a number of heavy metals (lead, chromium, arsenic, zinc, cadmium, copper, mercury and nickel) commonly found in contaminated soils. The principles, advantages and disadvantages of immobilization, soil washing and phytoremediation techniques which are frequently listed among the best demonstrated available technologies for cleaning up heavy metal contaminated sites are presented. Remediation of heavy metal contaminated soils is necessary to reduce the associated risks, make the land resource available for agricultural production, enhance food security and scale down land tenure problems arising from changes in the land use pattern.

scholarly journals New-Generation Washing Agents in Remediation of Metal-Polluted Soils and Methods for Washing Effluent Treatment: A Review

2020 ◽  
Vol 17 (17) ◽  
pp. 6220 ◽  
Author(s):  
Zygmunt M. Gusiatin ◽  
Dorota Kulikowska ◽  
Barbara Klik
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Contaminated Soils ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Soil Washing ◽  
Effluent Treatment ◽  
Chemical Pollution ◽  
Polluted Soils ◽  
Soil Flushing

Soil quality is seriously reduced due to chemical pollution, including heavy metal (HM) pollution. To meet quality standards, polluted soils must be remediated. Soil washing/soil flushing offers efficient removal of heavy metals and decreases environmental risk in polluted areas. These goals can be obtained by using proper washing agents to remove HMs from soil. These washing agents should not pose unacceptable threats to humans and ecosystems, including soil composition. Currently, it is desirable to use more environmentally and economically attractive washing agents instead of synthetic, environmentally problematic chemicals (e.g., ethylenediaminetetraacetic acid (EDTA)). The usefulness of novel washing agents for treatment of heavy metal-contaminated soils is being intensively developed, in terms of the efficiency of HM removal and properties of washed soils. Despite the unquestionable effectiveness of soil washing/flushing, it should be remembered that both methods generate secondary fluid waste (spent washing solution), and the final stage of the process should be treatment of the contaminated spent washing solution. This paper reviews information on soil contamination with heavy metals. This review examines the principles and status of soil washing and soil flushing. The novel contribution of this review is a presentation of the sources and characteristics of novel washing agents and chemical substitutes for EDTA, with their potential for heavy metal removal. Methods for treating spent washing solution are discussed separately.

Effects of Phosphate Rock on Absorption and Accumulation of Heavy Metals of Ryegrass in Heavy Metal Contaminated Soil

2014 ◽  
Vol 522-524 ◽  
pp. 752-757 ◽  
Author(s):  
Ying Zhe Wang ◽  
Zhong Qiu Zhao ◽  
Guang Yu Jiang
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Perennial Ryegrass ◽  
Significant Influence ◽  
Contaminated Soil ◽  
Contaminated Soils ◽  
Phosphate Rock ◽  
Particle Sizes ◽  
Cu And Zn ◽  
Soil Weight

The effects of phosphates rock (PR) with different particle sizes {D97<4.26 (the diameters of 97% of the particles are less than 4.26 µm.), <36.83, <71.12 and <101.43 µm} and different concentration (2.5% and 5% content of try soil weight) on immobilizing heavy metal-contaminated soils by a perennial ryegrass greenhouse experiment are conducted. Results indicate that remediation effect of applying 5% content is more significant than 2.5%. Ryegrass biomass in shoots in the former applying content is much larger than the latter and for both roots and shoots, PR reduces the absorption and accumulation of Pb, Cu and Zn, but no significant influence on Cd. While adding the same amount of different sizes of PR doesn’t show significant differences between these treatments. Pb content at 5% level of the finest size of PR is the minimum, decreased by 33% and 56% compared to the control in roots and shoots respectively, which was also suitable for Zn, decreased by 12.65% and 39.61% respectively.

scholarly journals Removal of heavy metals (Cu, Cd and Zn) from contaminated soils using EDTA and FeCl3

2016 ◽  
Vol 18 (1) ◽  
pp. 98-107 ◽  
Keyword(s):  
Heavy Metals ◽  
Contaminated Soils ◽  
Extraction Procedure ◽  
Soil Washing ◽  
Nitrilotriacetic Acid ◽  
Coarse Grained ◽  
Metal Extraction ◽  
Fine Grained ◽  
Solid Ratio ◽  
Fine Grained Soil

<p>Environmental pollution caused by heavy metals from different industrial activities constitutes a serious risk for the environment. Soils contaminated with metals, such as Cu, Cd and Zn, are often subjected to physical or chemical remediation procedures to purify soils from these metals. Typical chelating agents used for metal extraction and soil washing generally include ethylene-diaminetetraacetic acid nitrilotriacetic acid, diethylenetriaminepentaacetic acid and citric acid. The subject study evaluating the potential of soil washing methods using EDTA and ferric chloride on two types of soils (coarse grained, fine grained). The effects of operating parameters, such as liquid/solid ratio, soil washing chemicals and washing time were examined. In extraction procedure of Cd (266 mg kg<sup>-1</sup>), Cu (194 mg kg<sup>-1</sup>) and Zn (497 mg kg<sup>-1</sup>) from contaminated coarse grained soil with using 0.01 M FeCl<sub>3</sub> washing solution (liquid/solid ratio 20) for 2 hours, contaminants were removed 96.66%, 90.02% and 98.25%, respectively. In extraction procedure of Cd (218 mg kg<sup>-1</sup>), Cu (153 mg kg<sup>-1</sup>) and Zn (441.6 mg kg<sup>-1</sup>) from contaminated fine grained soil with using 0.01 M FeCl<sub>3</sub> washing solution (liquid/solid ratio 20) for 2 hours, contaminants were removed 98.18%, 97.48% and 98.05%, respectively. Better removal efficiencies have been obtained by using FeCl<sub>3</sub>. These results confirmed the effectiveness of the soil-washing method with FeCl<sub>3</sub> in remediating heavy metals (Cu, Cd and Zn) from different types of soil.</p>

Sequential Soil Flushing for Remediation of Complex Contaminated Soils: A Pilot-Scale Test

2014 ◽  
Vol 1073-1076 ◽  
pp. 704-707
Author(s):  
Kim Gillan ◽  
Sung Mi Yun ◽  
Han Seung Kim
Keyword(s):  
Heavy Metals ◽  
Contaminated Soils ◽  
Soil Surface ◽  
Pilot Scale ◽  
Ex Situ ◽  
Heavy Petroleum ◽  
Soil Flushing ◽  
Industrial Sites ◽  
Soil Complex

In this study, an efficient soil flushing process was developed for the remediation of soil complex contaminated with heavy petroleum oils (HPOs) and heavy metals. In most cases, remediation of contaminated soil is carried out after all industrial activity is suspended and removal of facilities. Therefore, in-situ remediation becomes more favored over ex-situ technologies albeit relatively long remediation periods are needed. In particular, soil flushing has been employed as an efficient in-situ technology most frequently in many railroad and industrial sites still in business. The objective of this study was to develop an in-situ soil flushing method using horizontal injection/suction channels. A pilot-scale box reactor (1 m × 0.6 m × 0.7 m) was employed to evaluate desorption of complex contaminants from complex contaminated soils by flushing agents. Since HPOs and heavy metals can be removed by different mechanisms, various flushing agents were required for the treatment of HPOs and heavy metals. Hydrogen peroxide (H2O2) and citric acid were selected and injected sequentially as flushing agents for HPOs and heavy metals, respectively. Soils complex contaminated with HPOs, Zn, and Pb were collected from a railroad site, Seoul, Korea, and they were packed into the pilot-scaled reactor. Two horizontal channels were installed: injection channel was placed 10 cm below the top of soil surface and suction channel was placed 10 cm above the bottom of the reactor. Flushing agents were injected at a flow rate of 3.86 mL/min for 1 month. After flushing, soil samples were collected separately from various points of the reactor (divided into 5 vertical layers and 15 horizontal sections), and then each soil sample was analyzed for the soil flushing efficiency. The initial concentrations of HPOs, Zn and Pb were 4685.5±374.4 mg/kg, 204.9±60 mg/kg, and 139.8 mg/kg (n = 3). After soil flushing, the concentrations were decreased to 1448.4±166.7 mg/kg, 143.4 mg/kg, and 99.5 mg/kg (total removal rates = 69%, 30% and 28.9%, for HPOs, Zn, and Pb, respectively). Hence, it was confirmed in this pilot-scale study that sequential soil flushing by combination of flushing agents was effective for soils complex contaminated with HPOs and heavy metals. These results must be useful for field-scale application of soil flushing remediation for the complex contaminated soils.

The phytoextraction potential of selected vegetable plants on Kosovo contaminated soils

2020 ◽  
Author(s):  
Teodoro Miano ◽  
Hana Voca ◽  
Lea Piscitelli ◽  
Anna Daniela Malerba ◽  
Donato Mondelli ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Contaminated Soils ◽  
Urban Areas ◽  
Human Health Risk ◽  
Translocation Factor ◽  
Heavy Metal Accumulation ◽  
Tolerance Index ◽  
Particulate Emissions ◽  
Experimental Conditions ◽  
High Level

&lt;p&gt;Mining activities generate a great deal of particulate emissions and waste slag enriched in heavy metals that contaminate the surrounding, that is soil, water and air. Such effects are particularly serious and pose a severe ecological and human health risk, mainly if smelters are located in the proximity of urban areas. This is the case regarding the Kosovo, where from the 1930s the British company &quot;Seltrust&quot; founded Trepca Mining &amp; Metallurgical Complex, causing a high level of pollution especially in the area of Mitrovic&amp;#235;, northern Kosovo. Two soils, A and B, have been sampled from two different sites in Mitrovic&amp;#235; municipality, showing a total content of Pb and Zn, respectively, of 2153 and 3087 mg kg&lt;sup&gt;-1&lt;/sup&gt;, and 3214 and 4619 mg kg&lt;sup&gt;-1&lt;/sup&gt;. A pot experiment was carried out aiming to understand the phytoremediation potential of two selected non-food crops (Sorghum bicolor L. Moench and Brassica napus cv. Westar) chosen for their economic importance and heavy metal accumulation capacities. Sorghum and canola plants were cultivated in polluted soils A and B. For both plant species, the accumulation of heavy metals proved to be higher in the roots. Indeed, in order to obtain an adequate phytoextraction, it is required that the metals be moved to the epigeal part of the plants, and plants with bioconcentration factor (BCF) and translocation factor (TF) values &lt; 1 are not considered suitable for phytoextraction. The results obtained in this study indicate that, although canola was quite effective in translocating metals from roots to aerial parts, both sorghum and canola are not suitable for phytoextraction since their coefficient values were &lt; 1. Anyway, both plants, especially canola ones, grew up in presence of high level of Pb and Zn pollution, thus they could be used for phytostabilisation process. Actually, the Tolerance Index (TI) values of the sorghum and canola clearly suggest, under the experimental conditions used in this study, a better performance of the canola in tolerating the presence of Pb and Zn in the soil, even if in soil B was not found the same efficiency shown by the same plants grown in soil A. Probably, since soil B has an absolute higher content of Pb and Zn and a lower pH, the availability of both metals is slightly higher, which may have induced in the plants that grow there a more intense condition of stress. This study shows that canola, unlike sorghum, can be an ideal choice for phytostabilization, and its breeding can represent an effective alternative to food crop.&amp;#160;&lt;/p&gt;

Removal of Heavy Metals from Contaminated Soils by Washing with Citric Acid and Subsequent Treatment of Soil-Washing Solutions

2014 ◽  
Vol 937 ◽  
pp. 646-651 ◽  
Author(s):  
Lei Sun ◽  
Han Qiao Liu ◽  
Guo Xia Wei ◽  
Zhen Hua Wu ◽  
Wei Yang
Keyword(s):  
Heavy Metals ◽  
Activated Carbon ◽  
Citric Acid ◽  
Contaminated Soils ◽  
Mixing Time ◽  
Soil Washing ◽  
Subsequent Treatment ◽  
Solution Ph ◽  
Citric Acid Concentration ◽  
Operating Variables

Soil washing experiments were carried out with citric acid as washing reagent for the remediation of soils highly contaminated with heavy metals, then activated carbon was used in absorption processing for leaching solution. In this study, the effects of the main operating variables for removal of metals from soils were first discussed. The results showed that 36.% Pb, 47.74% Cu and 61.88% Cd were removed from the contaminated soils by optimizing the washing parameters at citric acid concentration 0.2 mol/l, mixing time 2 h, liquid-soil ratio 20 and solution pH=4, respectively. In the adsorption experiments of leachates, the optimum conditions were found as follows: solution pH=7, mixing time of 2 h, standing time of 60 min and activated carbon dosage of 1g/100ml.

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