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1.
Xinyu Mao Fengxiang X. Han Xiaohou Shao Zikri Arslan Jacqueline McComb Tingting Chang Kai Guo Ahmet Celik 《Journal of Soils and Sediments》2016,16(10):2344-2353
Purpose
Extensive deposition of Pb, As, and Cs in soils may damage ecosystems and human’s health. Soil washing is the most conventional remediation method, and its efficiency depends on metal solubility in soil. This study aims to optimize operating variables of electro-kinetic field (EKF)-enhanced soil washing procedures.Materials and methods
Soil samples from a Mississippi River Delta rice field were homogeneously spiked with Pb, As, and Cs, and contaminated soil was aged for 3 months. The remediation involved a first stage electro-kinetic process, followed by a soil washing procedure. Soil pH changes under EKF were studied. Effects of citric acid and reversed EKF were investigated for alleviating possible alkaline precipitation. In the washing procedure, soil washing time and cycles with different extractants were examined. The overall EKF-enhanced soil washing efficiencies were discussed as well.Results and discussion
The implement of EKF offered an acidic soil environment around the anode areas for solubilizing metal(loid)s. Combined with EKF, citric acid was more conductive to desorb metal(loid)s. In addition, the reversed EKF effectively alleviated metal(loid) precipitation caused by alkalization in the first stage cathode areas. The EKF significantly enhanced metal(loid) extractions in the anode area of soils using Na2EDTA, CaCl2, and citric acid at pH of 2. The most preferable removal of Pb (80–98 %), As (48–63 %), and Cs (10–13 %) was achieved with three extractants. CaCl2 and citric acid were proved to be suitable alternatives to Na2EDTA for Pb extraction. A washing process of 2 h extraction with double washing cycles was optimized.Conclusions
Soil washing time and cycles were major factors governing the metal(loid) removal from soil. Washing process of 2 h extraction with double cycles was optimized for further extraction based on higher washing efficiency. The EKF effectively improved washing efficiency while some electrical parameters need further studies for cost performance consideration.2.
Mónica B. Alvarez Claudia E. Domini Mariano Garrido Adriana G. Lista Beatriz S. Fernández-Band 《Journal of Soils and Sediments》2011,11(4):657-666
Purpose
The objective of this research was to study heavy metal mobility and availability in sediment samples. A rapid diagnosis about metal behaviour was performed using the combination of several single-step extraction procedures and multi-way chemometric tools. 相似文献3.
Jia Wen Mike J. McLaughlin Samuel P. Stacey Jason K. Kirby 《Journal of Soils and Sediments》2010,10(7):1289-1299
Purpose
Successful chelant-assisted phytoextraction requires application of an eco-friendly metal-complexing agent which enhances metal uptake but does not pose a significant risk of off-site movement of metals. Rhamnolipid biosurfactant has been used to enhance cadmium (Cd) removal from contaminated soil by washing. It has a strong affinity for Cd compared to some other hazardous metals, suggesting that rhamnolipid could be useful in Cd phytoextraction. This study investigated the potential use of rhamnolipid to enhance Cd phytoextraction. 相似文献4.
Purpose
The aim of this study was to enhance the soil remediation of timber treatment sites; the potential application of biodegradable chelating agents and humic substances as enhancing agents was assessed in terms of the residual leachability of chromium, copper and arsenic (CCA).Materials and methods
This study applied four leachability tests on a field-contaminated soil after 48-h washing with ethylenediamine-N,N-disuccinic acid (EDDS), glutamic-N,N-diacetic acid, ethylenediaminetetraacetic acid and humic substances derived from lignite and two other sources.Results and discussion
It was noteworthy that the reduction in the total metal concentrations after soil washing was not predictive of the leaching behaviour. When assessed by toxicity characteristic leaching procedure (TCLP) and waste extraction test (WET), Cu and As leachability was decreased as a result of their extraction by soil washing. By contrast, when assessed by synthetic precipitation leaching procedure (SPLP) and European Council Waste Acceptance Criteria (ECWAC) tests, Cu and As leachability was found to increase, probably because the effect of destabilization of residual metals during soil washing was more observable in unbuffered leaching solutions. On the other hand, Cr leachability was acceptably low in TCLP and WET but still exceeded drinking water standard in SPLP and ECWAC tests.Conclusions
The three chelating agents were able to meet the criteria for Cu in all leachability tests, while the limits of As concentrations could only be met by EDDS in TCLP test. The three humic substances reduced the leachate concentrations of Cu and As without destabilizing the residual metals; however, the reduction was insufficient to meet the required limits in all leachability tests considered. 相似文献5.
Lea Rastas Amofah Christian Maurice Jurate Kumpiene Prosun Bhattacharya 《Journal of Soils and Sediments》2011,11(8):1334-1344
Purpose
Normal soil washing leave high residual pollutant content in soil. The remediation could be improved by targeting the extraction to coarser fractions. Further, a low/high extraction pH and higher temperature enhance the pollutant removal, but these measures are costly. In this study, the utility of NaOH, oxalate–citrate (OC) and dithionite–citrate–oxalate (DCO) solutions for extracting of arsenic, chromium and zinc from contaminated soil were assessed and compared. In addition the effects of NaOH concentration and temperature on NaOH extractions, and those of temperature and pH on OC and DCO extractions, were evaluated. 相似文献6.
Patricia Miretzky Monica Rodriguez Avendaño Carolina Muñoz Alejandro Carrillo-Chavez 《Journal of Soils and Sediments》2011,11(4):619-627
Purpose
Tessier's sequential extraction method is usually used to study metal parting among different phases in soils. The main objective of this study was to determine the redistribution of trace metals which were added simultaneously to a sandy loam soil by use of the fractional distribution and reduced partition indexes and the risk of assessment code (RAC). 相似文献7.
Background Goal and Scope
The application of solid-liquid extraction is proposed to assess extractable fractions of components in soil. The application of a several step scheme could give a lot of information about mobility of metals associated with specific solid phases, especially after separation of top and bottom layers of studied soil. In this study, it was aimed to take into solution metal fractions of major (Ca, Mg, Mn, Fe) and trace elements (Cr, Co, Cu, Zn, As, Cd, Pb) from soil collected in urban areas. The fractions were defined by using chemical extraction operationally. The extraction behavior of studied elements in a six-step sequential extraction procedure is discussed with respect to the properties of the reagents used. 相似文献8.
Purpose
This study aimed to compare the effectiveness of chemical-enhanced soil washing (with chelating agents, humic substances and inorganic acids) and soil stabilisation by inorganic industrial by-products (coal fly ash, acid mine drainage sludge and zero-valent iron) and organic resource (lignite) for timber treatment site remediation.Materials and methods
Both remediation options were assessed in terms of extraction/leaching kinetics and residual leachability (toxicity characteristic leaching procedure, TCLP) of the major risk drivers, i.e. Cu and As.Results and discussion
In chemical-enhanced soil washing, chelating agents only minimised the Cu leachability. Humic substances were ineffective while inorganic acids reduced the As leachability to the detriment of the soil quality. For the waste-stabilised soil, the short-term leaching potential (72 h) and long-term TCLP leachability (9 months) revealed that Fe-/Al-/Ca-rich AMD sludge and coal fly ash sequestered As through adsorption and (co-)precipitation, while carbonaceous lignite stabilised Cu with oxygen-containing functional groups. The short-term and long-term leaching of Cu and As into the soil solution was negligible in the presence of the waste materials. However, the waste-stabilised soil did not maintain sufficient Cu stability in the TCLP tests, in which acetate buffer induced significant mineral dissolution of the waste materials.Conclusions
These results suggest that chelant-enhanced washing (significant reduction of Cu leachability) may be augmented with subsequent stabilisation with inorganic waste materials (effective control of As leachability), thus minimising the environmental risks of both Cu (heavy metal) and As (metalloid) while preserving the reuse value of the soil. Additional tests under field-relevant conditions are required to provide a holistic performance evaluation. 相似文献9.
Ming Lei Baiqing Tie Paul N. Williams Yuanming Zheng Yizong Huang 《Journal of Soils and Sediments》2011,11(1):115-123
Purpose
Hunan province is well-known for its extensive base-metal extraction and smelting industries. However, the legacies of excavation operations, transportation, and selective smelting activities within Hunan have resulted in the generation of large quantities of mine wastes, which will become the sources of metal contamination in the environment. Thus, there is an increasingly important health issue underlying the study of arable land pollution and transfer of As, Cd, and Pb in the paddy soil–rice system. 相似文献10.
Removal of trace and major metals by soil washing with Na<Subscript>2</Subscript>EDTA and oxalate 总被引：1，自引：0，他引：1
Rongliang Qiu Zeli Zou Zhihao Zhao Weihua Zhang Tao Zhang Hanying Dong Xiange Wei 《Journal of Soils and Sediments》2010,10(1):45-53
Background, aim, and scope
Various metals such as cationic metals (Cu, Pb, Zn) and anionic metals (As, Cr) often coexist in real soils, and normal soil washing techniques for the removal of cationic metals with a single-washing reagent make it rather difficult to simultaneously remove all of them. Oxalate could effectively remove anionic As and EDTA could effectively remove the cationic metals, so it was possible to remove all coexisting cationic and anionic metals by washing with the combination of Na2EDTA and oxalate. The objective of this study was to (1) discuss the possibility of removing five metals, As, Cd, Cu, Pb, and Zn, effectively from the soil by washing with Na2EDTA-combined oxalate; (2) optimized through the consecutive washing. 相似文献11.
Claudia Rocco Diana Agrelli Ida Coppola Isabel González Paola Adamo 《Journal of Soils and Sediments》2018,18(6):2282-2291
Purpose
Phytostabilization with native plant species might represent an economically more realistic and cost-effective option than excavation, soil washing, and sludge disposal for rehabilitation of degraded and polluted industrial areas. This work was done to assess the changes induced by native plant revegetation in the chemical properties and mobility-bioavailability of Pb and Zn pollutants of soil and post-washing sludges from an Italian brownfield site of national interest.Materials and methods
A 5-year native plant revegetation of polluted soil and relative post-washing sludges from a steel plant was achieved in situ and ex situ in pot and in the presence and absence of peat as organic amendment. During the experiment, the vegetation growth was monitored (Adamo et al. In Int J Environ Sci Technol 12(6):1811–1824, 2015). Before and after plant growth, the substrates were studied for pH, organic carbon, and carbonate contents. Lead, Zn, and other metal mobility and leachability were investigated by water extraction. The metal bioavailability was estimated by diethylenetriaminepentaacetic acid (DTPA) extraction at pH 7.3. Sequential extractions (BCR procedure) were used to fractionate Pb and Zn in soil main geochemical forms. Plant ability to uptake metals was evaluated on the three most representative species: Bituminaria bituminosa, Daucus carota, and Dactylis glomerata.Results and discussion
After 5 years of revegetation with native plants, the substrate pH and organic carbon content were respectively decreased and increased by plant growth, with changes masked by peat treatments. Although metal pollutants in both substrates were characterized by low water solubility and DTPA availability, after plant growth, an increase of rhizospheric Zn, Cu, Fe, and Mn solubility in H2O was detected. According to metal speciation, Pb and Zn were largely occluded in easily reducible manganese/iron oxides and trapped in the mineral structure of silicates, with no visible changes of distribution after plants. Water extraction always underestimated plant uptake, whereas DTPA and sequential extractions better predicted Pb and Zn uptake.Conclusions
Despite the original extremely low mobility and bioavailability of metal pollutants in both soil and post-washing sludges, the acidification and increase of organic carbon content induced by peat amendments and plant growth enhance the solubility in water of metal-containing compounds. Therefore, attention must be paid to these effects in the long period. A continuous monitoring of the changes of pollutant mobility-bioavailability induced by native plant revegetation of brownfields is crucial to prevent risks to the surrounding environment and human health.12.
Purpose
Organic dyes have been turned into an important emerging type of chemical pollutants with the development of rural textiles, synthetic dye, printing, and dyeing industries and the continuous release from washing fabrics and clothes in recent decades. In order to assess ecological risk of reactive X-3B red dye as a typical dye, the adsorptive and desorptive traits of the dye in soils were investigated and the environmental factors influencing those processes were examined and discussed. 相似文献13.
Background
In practical farming, there is often a need for short-term availability of information on the soil nutrient status.Aims
To develop a new express method for the extraction of major plant-available nutrients and measurement of soil nutrients. In future, this method shall serve for in-field measurements of soil samples with an ion-sensitive field-effect transistor (ISFET).Methods
Various extraction conditions such as type of extractant, soil-to-solution ratio, time, and intensity were investigated on a broad selection of dried soil samples in the laboratory. Based on 83 field-moist soil samples with varying clay contents, these conditions were compared to standard laboratory methods.Results
With increasing extraction time, the nutrient concentrations increased. When the soil-to-solution ratio was reduced, a greater share of nutrients was extracted, independent of soil type. H2O and 0.01 M CaCl2 and standard calcium-acetate-lactate (CAL) solution proved to be too weak in the short period to reach the ISFET sensor measurement range. Higher concentrated CAL solutions performed much better. Finally, a 5-min CaCl2 extraction followed by the removal of an aliquot for the determination of soil pH and NO3− was found to be effective. The remaining solution was then mixed with 0.20 M CAL solution for the analysis of H2PO4− and K+ at 10 min of extra extraction time. This extraction method showed very good correlations with the values based on the German laboratory reference methods for pH (R2 = 0.91) and for nitrate (R2 = 0.95). For phosphorus and potassium, we obtained an R2 of 0.70 and 0.81, respectively, for all soils. When soils were grouped according to clay content higher correlations were found.Conclusions
A new express method based on a wet-chemical approach with a soil preparation procedure was successfully developed and validated. This seems to be a valuable basis for future in-field measurements via ISFET. 相似文献14.
Jining Li Tomoya Kosugi Shohei Riya Yohey Hashimoto Hong Hou Akihiko Terada Masaaki Hosomi 《Journal of Soils and Sediments》2017,17(8):2136-2143
Purpose
In Japan, the excavated soils produced from constructions projects, which contain relatively low levels of arsenic (As), are considered as a potential concern if they could release significant amount of As to the environment. The aim of this study was to investigate the As leaching from excavated alkaline soils and, in particular, the influence of drying methods, pH of extracting solution, and consecutive washing on As leaching from these soils.Materials and methods
Four excavated alkaline soils obtained from different construction sites in Tokyo, Japan, were used in this study. The soils were pretreated by three drying methods (air-dried, 40 °C-dried, and freeze-dried). Sequential extraction procedure was applied to partition As into five operationally defined chemical fractions. Batch leaching tests (initial pH-controlled leaching test and consecutive washing test) were conducted to investigate the As release under different leaching conditions.Results and discussion
The As contents in the four soils were 9.22, 79.4, 6.75, and 11.7 mg kg?1, respectively, and As was primarily associated with the residual phase. Arsenic leaching was strongly dependent on the extracting solution pH values. Strongly acidic extracting solution (pH 2) led to circumneutral leachates and limited As mobility, whereas the strong alkaline-extracting solution (pH 12) greatly enhanced the As release from these soils. The consecutive washing test results revealed a long-term release of As from these excavated soils. The pollution potential indices (PPIs) were successfully used to evaluate the pollution threat of As leaching from excavated soils. In addition, different drying methods resulted in variations in the short- and long-term release of As from these excavated soils.Conclusions
The results revealed that the soil pretreatment and the leaching conditions should be considered if we want to use batch tests for the contamination assessment of excavated urban soils from construction projects. Different drying methods and single extraction may lead to misestimation of the As pollution level. High extraction efficiency with strong alkaline-extracting solution (pH 12) reveals that it could potentially be used to wash As from excavated alkaline soils.15.
Michael A. Schmidt Jonathan J. Halvorson Javier M. Gonzalez Ann E. Hagerman 《Journal of Soils and Sediments》2012,12(3):366-375
Purpose
We investigated tannin–soil interactions by assessing the kinetics of sorption and sorption capacities, and their relationship to the chemical properties of six polyphenolic compounds and the textures of six soils. We developed a new extraction procedure for recovering tannins from soil samples by successive extraction with solvents of decreasing polarity. 相似文献16.
Antonio María Cervantes Hector Miguel Conesa María Nazaret González-Alcarez José Álvarez-Rogel 《Journal of Soils and Sediments》2011,11(5):800-814
Purpose
The aim of this work was to study the risk of As and metal pollution in saline wetlands affected by slightly acidic mine wastes, in the presence or absence of a plant rhizosphere, under different flooding regimes. Some guidelines for management will be proposed in order to minimise the risk of metal leaching in metal-polluted salt marshes. 相似文献17.
Background, aim and scope
This paper discusses a method investigating the reduction of free heavy metal cation contents in soil through the use of microbe-inducing precipitate (MIP). 相似文献18.
Background, aim, and scope
The cause for this position paper is the impression that risk assessors consider primarily the concentration of free metal ions dissolved in solution controlling metal bioavailability in aquatic systems. Aiming at a more realistic risk assessment of metals, bioavailability has to be discussed under the scope of main uptake routes of metals to organisms. 相似文献19.
Miriam Katherine Reid Kate L. Spencer Laura Shotbolt 《Journal of Soils and Sediments》2011,11(3):518-528
Purpose
The purpose of this research was to assess the precision and accuracy of a BCR and Tessier microwave-assisted sequential extraction procedure, in comparison to the conventional versions for a range of metals using a soil, lake and estuarine certified reference material (CRM). 相似文献20.
Effects of bacteria on metal bioavailability,speciation, and mobility in different metal mine soils: a column study 总被引：1，自引：0，他引：1