Sample records for actual contaminated soil

  1. Cesium desorption behavior of weathered biotite in Fukushima considering the actual radioactive contamination level of soils.

    PubMed

    Mukai, Hiroki; Tamura, Kenji; Kikuchi, Ryosuke; Takahashi, Yoshio; Yaita, Tsuyoshi; Kogure, Toshihiro

    2018-10-01

    For the better understanding of radioactive contamination in Fukushima Prefecture at present and in future, Cs desorption experiments have been conducted mainly using weathered biotite (WB) collected from Fukushima Prefecture and considering the actual contamination level (∼10 -10  wt%) of radiocesium in Fukushima Prefecture. In the experiments, 137 Cs sorbed to WB by immersing in 137 Cs solution for one day was mostly desorbed by solutions of 1 M NaNO 3 , 1 M LiNO 3 , 10 -1  M HCl, and 10 -1  M HNO 3 , although it was barely desorbed by 1 M KNO 3 , 1 M CsNO 3 , 1 M NH 4 NO 3 , and natural seawater. X-ray diffraction analysis of WB after immersing in these solutions suggested that the collapse of the hydrated interlayers in WB suppressed the desorption of Cs. On the other hand, 137 Cs was barely desorbed from WB even by the treatments with solutions of NaNO 3 and LiNO 3 if the duration for the sorption was longer than approximately two weeks, as well as radioactive WB collected from actual contaminated soils in Fukushima Prefecture. This result implies that Cs sorbed in WB became more strongly fixed with time. Probably removal of radiocesium sorbed in weathered granitic soil at Fukushima Prefecture is difficult by any electrolyte solutions, as more than seven years have passed since the accident. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. The organic contamination level based on the total soil mass is not a proper index of the soil contamination intensity

    USGS Publications Warehouse

    Hung, H.-W.; Daniel, Sheng G.; Lin, T.-F.; Su, Y.; Chiou, C.T.

    2009-01-01

    Concentrations of organic contaminants in common productive soils based on the total soil mass give a misleading account of actual contamination effects. This is attributed to the fact that productive soils are essentially water-saturated, with the result that the soil uptake of organic compounds occurs principally by partition into the soil organic matter (SOM). This report illustrates that the soil contamination intensity of a compound is governed by the concentration in the SOM (Com) rather than by the concentration in whole soil (Cs). Supporting data consist of the measured levels and toxicities of many pesticides in soils of widely differing SOM contents and the related levels in in-situ crops that defy explanation by the Cs values. This SOM-based index is timely needed for evaluating the contamination effects of food crops grown in different soils and for establishing a dependable priority ranking for intended remediation of numerous contamination sites.

  3. Assays of dioxins and dioxin-like compounds in actually contaminated soils using transgenic tobacco plants carrying a recombinant mouse aryl hydrocarbon receptor-mediated β-glucuronidase reporter gene expression system.

    PubMed

    Inui, Hideyuki; Gion, Keiko; Utani, Yasushi; Wakai, Taketo; Kodama, Susumu; Eun, Heesoo; Kim, Yun-Seok; Ohkawa, Hideo

    2012-01-01

    The transgenic tobacco plant XD4V-26 carrying the recombinant mouse aryl hydrocarbon receptor XD4V-mediated β-glucuronidase (GUS) reporter gene expression system was used for assay of dioxins and dioxin-like compounds consisting of polychlorinated dibenzeno-p-dioxins, polychlorinated dibenzofurans, and coplanar polychlorinated biphenyls (Co-PCBs) in actually contaminated soils. The transgenic tobacco plant XD4V-26 showed a significant dose-dependent induced GUS activity when cultured on MS medium containing PCB126 [toxic equivalency factor (TEF) = 0.1]. In contrast, PCB169 and PCB180, which have 0.03 of TEF and unassigned TEF values, respectively, did not significantly induce GUS activity under the same conditions as with PCB126. When the tobacco plants were cultivated for up to 5 weeks on actually contaminated soils with dioxins and dioxin-like compounds collected from the periphery of an incinerator used for disposal of residential and industrial wastes, GUS activity in the leaves was dose-dependently increased. The plants clearly detected 360 pg-TEQ g(-1) of dioxins and dioxin-like compounds in this assay. There was a positive correlation between GUS activity and TEQ value of dioxins and dioxin-like compounds in the plants. This assay does not require any extraction and purification processes for the actually contaminated soil samples.

  4. Assays of dioxins and dioxin-like compounds in actually contaminated soils using transgenic tobacco plants carrying a recombinant mouse aryl hydrocarbon receptor-mediated β-glucuronidase reporter gene expression system.

    PubMed

    Inui, Hideyuki; Gion, Keiko; Utani, Yasushi; Wakai, Taketo; Kodama, Susumu; Eun, Heesoo; Kim, Yun-Seok; Ohkawa, Hideo

    2012-01-01

    The transgenic tobacco plant XD4V-26 carrying the recombinant mouse aryl hydrocarbon receptor XD4V-mediated β-glucuronidase (GUS) reporter gene expression system was used for assay of dioxins and dioxin-like compounds consisting of polychlorodibenzo-p-dioxins, polychlorinated dibenzofurans, and coplanar polychlorinated biphenyls (Co-PCBs) in actually contaminated soils. The transgenic tobacco plant XD4V-26 showed a significant dose-dependent induced GUS activity when cultured on MS medium containing PCB126 [toxic equivalency factor (TEF) = 0.1]. In contrast, PCB169 and PCB180, which have 0.03 of TEF and unassigned TEF values, respectively, did not significantly induce GUS activity under the same conditions as with PCB126. When the tobacco plants were cultivated for up to 5 weeks on actually contaminated soils with dioxins and dioxin-like compounds collected from the periphery of an incinerator used for disposal of life and industrial wastes, GUS activity in the leaves was dose-dependently increased. The plants clearly detected 360 pg-TEQ g(-1) of dioxins and dioxin-like compounds in this assay. There was a positive correlation between GUS activity and TEQ value of dioxins and dioxin-like compounds in the plants. This assay does not require any extraction and purification processes for the actually contaminated soil samples.

  5. Assays of dioxins and dioxin-like compounds in actually contaminated soils using transgenic tobacco plants carrying a recombinant mouse aryl hydrocarbon receptor-mediated β-glucuronidase reporter gene expression system

    PubMed Central

    Inui, Hideyuki; Gion, Keiko; Utani, Yasushi; Wakai, Taketo; Kodama, Susumu; Eun, Heesoo; Kim, Yun-Seok; Ohkawa, Hideo

    2012-01-01

    The transgenic tobacco plant XD4V-26 carrying the recombinant mouse aryl hydrocarbon receptor XD4V-mediated β-glucuronidase (GUS) reporter gene expression system was used for assay of dioxins and dioxin-like compounds consisting of polychlorodibenzo-p-dioxins, polychlorinated dibenzofurans, and coplanar polychlorinated biphenyls (Co-PCBs) in actually contaminated soils. The transgenic tobacco plant XD4V-26 showed a significant dose-dependent induced GUS activity when cultured on MS medium containing PCB126 [toxic equivalency factor (TEF) = 0.1]. In contrast, PCB169 and PCB180, which have 0.03 of TEF and unassigned TEF values, respectively, did not significantly induce GUS activity under the same conditions as with PCB126. When the tobacco plants were cultivated for up to 5 weeks on actually contaminated soils with dioxins and dioxin-like compounds collected from the periphery of an incinerator used for disposal of life and industrial wastes, GUS activity in the leaves was dose-dependently increased. The plants clearly detected 360 pg-TEQ g−1 of dioxins and dioxin-like compounds in this assay. There was a positive correlation between GUS activity and TEQ value of dioxins and dioxin-like compounds in the plants. This assay does not require any extraction and purification processes for the actually contaminated soil samples. PMID:22428884

  6. Electrokinetic remediation of fluorine-contaminated soil and its impact on soil fertility.

    PubMed

    Zhou, Ming; Wang, Hui; Zhu, Shufa; Liu, Yana; Xu, Jingming

    2015-11-01

    Compared to soil pollution by heavy metals and organic pollutants, soil pollution by fluorides is usually ignored in China. Actually, fluorine-contaminated soil has an unfavorable influence on human, animals, plants, and surrounding environment. This study reports on electrokinetic remediation of fluorine-contaminated soil and the effects of this remediation technology on soil fertility. Experimental results showed that electrokinetic remediation using NaOH as the anolyte was a considerable choice to eliminate fluorine in contaminated soils. Under the experimental conditions, the removal efficiency of fluorine by the electrokinetic remediation method was 70.35%. However, the electrokinetic remediation had a significant impact on the distribution and concentrations of soil native compounds. After the electrokinetic experiment, in the treated soil, the average value of available nitrogen was raised from 69.53 to 74.23 mg/kg, the average value of available phosphorus and potassium were reduced from 20.05 to 10.39 mg/kg and from 61.31 to 51.58 mg/kg, respectively. Meanwhile, the contents of soil available nitrogen and phosphorus in the anode regions were higher than those in the cathode regions, but the distribution of soil available potassium was just the opposite. In soil organic matter, there was no significant change. These experiment results suggested that some steps should be taken to offset the impacts, after electrokinetic treatment.

  7. Extraction behavior of metallic contaminants and soil constituents from contaminated soils.

    PubMed

    Tokunaga, S; Park, S W; Ulmanu, M

    2005-06-01

    With an aim of developing an effective remediation technology for soils contaminated by heavy metals and metalloids, the extraction behavior of metallic contaminants as well as those of soil constituents was studied on a laboratory scale. Three contaminated soils collected from a former metal recycling plant were examined. These three soils were found to be contaminated by As, Cu, Pb, Sb, Se and Zn as compared to the non-contaminated soil. The pH-dependent extraction behavior of various elements from the soils was measured in a wide pH range and categorized into three groups. Hydrochloric acid (HCl), H2SO4, H3PO4, HNO3, sodium citrate, sodium tartrate, disodium dihydrogen ethylenediaminetetraacetate and diethylenetriaminepentaacetic acid were evaluated as extractants for removing contaminants from the soils. Extraction behavior of the soil constituents was also studied. The efficiency of the extraction was evaluated by the Japanese content and leaching tests. The stabilization of Pb remaining in the soil after the extraction process was conducted by the addition of iron(III) and calcium chloride.

  8. Evaluating soil contamination

    USGS Publications Warehouse

    Beyer, W.N.

    1990-01-01

    This compilation was designed to help U.S. Fish and Wildlife Service contaminant specialists evaluate the degree of contamination of a soil, based on chemical analyses. Included are regulatory criteria, opinions, brief descriptions of scientific articles, and miscellaneous information that might be useful in making risk assessments. The intent was to make hard-to-obtain material readily available to contaminant specialists, but not to critique the material or develop new criteria. The compilation is to be used with its index, which includes about 200 contaminants. There are several entries for a few of the most thoroughly studied contaminants, but for most of them the information available is meager. Entries include soil contaminant criteria from other countries, contaminant guidelines for applying sewage sludge to soil, guidelines for evaluating sediments, background soil concentrations for various elements, citations to scientific articles that may help estimate the potential movement of soil contaminants into wildlife food chains, and a few odds and ends. Articles on earthworms were emphasized because they are a natural bridge between soil and many species of wildlife.

  9. Microbial Degradation of Phenanthrene in Pristine and Contaminated Sandy Soils.

    PubMed

    Schwarz, Alexandra; Adetutu, Eric M; Juhasz, Albert L; Aburto-Medina, Arturo; Ball, Andrew S; Shahsavari, Esmaeil

    2018-05-01

    Phenanthrene mineralisation studies in both pristine and contaminated sandy soils were undertaken through detailed assessment of the activity and diversity of the microbial community. Stable isotope probing (SIP) was used to assess and identify active 13 C-labelled phenanthrene degraders. Baseline profiling indicated that there was little difference in fungal diversity but a significant difference in bacterial diversity dependent on contamination history. Identification of dominant fungal and bacterial species highlighted the presence of organisms capable of degrading various petroleum-based compounds together with other anthropogenic compounds, regardless of contamination history. Community response following a simulated contamination event ( 14 C-phenanthrene) showed that the microbial community in deep pristine and shallow contaminated soils adapted most to the presence of phenanthrene. The similarity in microbial community structure of well-adapted soils demonstrated that a highly adaptable fungal community in these soils enabled a rapid response to the introduction of a contaminant. Ten fungal and 15 bacterial species were identified as active degraders of phenanthrene. The fungal degraders were dominated by the phylum Basidiomycota including the genus Crypotococcus, Cladosporium and Tremellales. Bacterial degraders included the genera Alcanivorax, Marinobacter and Enterococcus. There was little synergy between dominant baseline microbes, predicted degraders and those that were determined to be actually degrading the contaminant. Overall, assessment of baseline microbial community in contaminated soils provides useful information; however, additional laboratory assessment of the microbial community's ability to degrade pollutants allows for better prediction of the bioremediation potential of a soil.

  10. Bioremediation of diesel oil-contaminated soil by composting with biowaste.

    PubMed

    Van Gestel, Kristin; Mergaert, Joris; Swings, Jean; Coosemans, Jozef; Ryckeboer, Jaak

    2003-01-01

    Soil spiked with diesel oil was mixed with biowaste (vegetable, fruit and garden waste) at a 1:10 ratio (fresh weight) and composted in a monitored composting bin system for 12 weeks. Pure biowaste was composted in parallel. In order to discern the temperature effect from the additional biowaste effect on diesel degradation, one recipient with contaminated soil was hold at room temperature, while another was kept at the actual composting temperature. Measurements of composting parameters together with enumerations and identifications of microorganisms demonstrate that the addition of the contaminated soil had a minor impact on the composting process. The first-order rate constant of diesel degradation in the biowaste mixture was four times higher than in the soil at room temperature, and 1.2 times higher than in the soil at composting temperature.

  11. Comparison of the effectiveness of soil heating prior or during in situ chemical oxidation (ISCO) of aged PAH-contaminated soils.

    PubMed

    Ranc, Bérénice; Faure, Pierre; Croze, Véronique; Lorgeoux, Catherine; Simonnot, Marie-Odile

    2017-04-01

    Thermal treatments prior or during chemical oxidation of aged polycyclic aromatic hydrocarbon (PAH)-contaminated soils have already shown their ability to increase oxidation effectiveness. However, they were never compared on the same soil. Furthermore, oxygenated polycyclic aromatic hydrocarbons (O-PACs), by-products of PAH oxidation which may be more toxic and mobile than the parent PAHs, were very little monitored. In this study, two aged PAH-contaminated soils were heated prior (60 or 90 °C under Ar for 1 week) or during oxidation (60 °C for 1 week) with permanganate and persulfate, and 11 O-PACs were monitored in addition to the 16 US Environmental Protection Agency (US EPA) PAHs. Oxidant doses were based on the stoichiometric oxidant demand of the extractable organic fraction of soils by using organic solvents, which is more representative of the actual contamination than only the 16 US EPA PAHs. Higher temperatures actually resulted in more pollutant degradation. Two treatments were about three times more effective than the others: soil heating to 60 °C during persulfate oxidation and soil preheating to 90 °C followed by permanganate oxidation. The results of this study showed that persulfate effectiveness was largely due to its thermal activation, whereas permanganate was more sensitive to PAH availability than persulfate. The technical feasibility of these two treatments will soon be field-tested in the unsaturated zone of one of the studied aged PAH-contaminated soils.

  12. Potential microbial contamination during sampling of permafrost soil assessed by tracers

    NASA Astrophysics Data System (ADS)

    Bang-Andreasen, Toke; Schostag, Morten; Priemé, Anders; Elberling, Bo; Jacobsen, Carsten S.

    2017-02-01

    Drilling and handling of permanently frozen soil cores without microbial contamination is of concern because contamination e.g. from the active layer above may lead to incorrect interpretation of results in experiments investigating potential and actual microbial activity in these low microbial biomass environments. Here, we present an example of how microbial contamination from active layer soil affected analysis of the potentially active microbial community in permafrost soil. We also present the development and use of two tracers: (1) fluorescent plastic microspheres and (2) Pseudomonas putida genetically tagged with Green Fluorescent Protein production to mimic potential microbial contamination of two permafrost cores. A protocol with special emphasis on avoiding microbial contamination was developed and employed to examine how far microbial contamination can penetrate into permafrost cores. The quantity of tracer elements decreased with depth into the permafrost cores, but the tracers were detected as far as 17 mm from the surface of the cores. The results emphasize that caution should be taken to avoid microbial contamination of permafrost cores and that the application of tracers represents a useful tool to assess penetration of potential microbial contamination into permafrost cores.

  13. Potential microbial contamination during sampling of permafrost soil assessed by tracers.

    PubMed

    Bang-Andreasen, Toke; Schostag, Morten; Priemé, Anders; Elberling, Bo; Jacobsen, Carsten S

    2017-02-23

    Drilling and handling of permanently frozen soil cores without microbial contamination is of concern because contamination e.g. from the active layer above may lead to incorrect interpretation of results in experiments investigating potential and actual microbial activity in these low microbial biomass environments. Here, we present an example of how microbial contamination from active layer soil affected analysis of the potentially active microbial community in permafrost soil. We also present the development and use of two tracers: (1) fluorescent plastic microspheres and (2) Pseudomonas putida genetically tagged with Green Fluorescent Protein production to mimic potential microbial contamination of two permafrost cores. A protocol with special emphasis on avoiding microbial contamination was developed and employed to examine how far microbial contamination can penetrate into permafrost cores. The quantity of tracer elements decreased with depth into the permafrost cores, but the tracers were detected as far as 17 mm from the surface of the cores. The results emphasize that caution should be taken to avoid microbial contamination of permafrost cores and that the application of tracers represents a useful tool to assess penetration of potential microbial contamination into permafrost cores.

  14. Potential microbial contamination during sampling of permafrost soil assessed by tracers

    PubMed Central

    Bang-Andreasen, Toke; Schostag, Morten; Priemé, Anders; Elberling, Bo; Jacobsen, Carsten S.

    2017-01-01

    Drilling and handling of permanently frozen soil cores without microbial contamination is of concern because contamination e.g. from the active layer above may lead to incorrect interpretation of results in experiments investigating potential and actual microbial activity in these low microbial biomass environments. Here, we present an example of how microbial contamination from active layer soil affected analysis of the potentially active microbial community in permafrost soil. We also present the development and use of two tracers: (1) fluorescent plastic microspheres and (2) Pseudomonas putida genetically tagged with Green Fluorescent Protein production to mimic potential microbial contamination of two permafrost cores. A protocol with special emphasis on avoiding microbial contamination was developed and employed to examine how far microbial contamination can penetrate into permafrost cores. The quantity of tracer elements decreased with depth into the permafrost cores, but the tracers were detected as far as 17 mm from the surface of the cores. The results emphasize that caution should be taken to avoid microbial contamination of permafrost cores and that the application of tracers represents a useful tool to assess penetration of potential microbial contamination into permafrost cores. PMID:28230151

  15. Phytoremediation of Metal-Contaminated Soils

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Shtangeeva, I.; Laiho, J.V-P.; Kahelin, H.

    2004-03-31

    Recent concerns regarding environmental contamination have necessitated the development of appropriate technologies to assess the presence and mobility of metals in soil and estimate possible ways to decrease the level of soil metal contamination. Phytoremediation is an emerging technology that may be used to cleanup contaminated soils. Successful application of phytoremediation, however, depends upon various factors that must be carefully investigated and properly considered for specific site conditions. To efficiently affect the metal removal from contaminated soils we used the ability of plants to accumulate different metals and agricultural practices to improve soil quality and enhance plant biomass. Pot experimentsmore » were conducted to study metal transport through bulk soil to the rhizosphere and stimulate transfer of the metals to be more available for plants' form. The aim of the experimental study was also to find fertilizers that could enhance uptake of metals and their removal from contaminated soil.« less

  16. Sustainable decontamination of an actual-site aged PCB-polluted soil through a biosurfactant-based washing followed by a photocatalytic treatment.

    PubMed

    Occulti, Fabio; Roda, Giovanni Camera; Berselli, Sara; Fava, Fabio

    2008-04-15

    A two phases process consisting of a soya lecithin (SL)-based soil washing process followed by the photocatalytic treatment of resulting effluents was developed and applied at the laboratory scale in the remediation of an actual-site soil historically contaminated by 0.65 g/kg of polychlorinated biphenyls (PCBs). Triton X-100 (TX) was employed in the same process as a control surfactant. SL and TX, both applied as 2.25 g/L aqueous solutions, displayed a comparable ability to remove PCBs from the soil. However, SL solution displayed a lower ecotoxicity, a lower ability to mobilize soil constituents and a higher soil detoxification capacity with respect to the TX one. The photocatalytic treatment resulted in marked depletions (from 50% to 70%) of total organic carbon (TOC) and PCBs initially occurring in the SL and TX contaminated effluents. Despite the ability of SL to adversely affect the rate of TOC and PCB photodegradation, higher PCB depletion and dechlorination yields along with lower increases of ecotoxicity were observed in SL-containing effluents with respect to the TX ones at the end of 15 days of treatment. The two phases process developed and tested for the first time in this study seems to have the required features to become, after a proper optimization and scale up, a challenging procedure for the sustainable remediation of actual site, poorly biotreatable PCB-contaminated soils. Copyright 2007 Wiley Periodicals, Inc.

  17. Layer of organic pine forest soil on top of chlorophenol-contaminated mineral soil enhances contaminant degradation.

    PubMed

    Sinkkonen, Aki; Kauppi, Sari; Simpanen, Suvi; Rantalainen, Anna-Lea; Strömmer, Rauni; Romantschuk, Martin

    2013-03-01

    Chlorophenols, like many other synthetic compounds, are persistent problem in industrial areas. These compounds are easily degraded in certain natural environments where the top soil is organic. Some studies suggest that mineral soil contaminated with organic compounds is rapidly remediated if it is mixed with organic soil. We hypothesized that organic soil with a high degradation capacity even on top of the contaminated mineral soil enhances degradation of recalcitrant chlorophenols in the mineral soil below. We first compared chlorophenol degradation in different soils by spiking pristine and pentachlorophenol-contaminated soils with 2,4,6-trichlorophenol in 10-L buckets. In other experiments, we covered contaminated mineral soil with organic pine forest soil. We also monitored in situ degradation on an old sawmill site where mineral soil was either left intact or covered with organic pine forest soil. 2,4,6-Trichlorophenol was rapidly degraded in organic pine forest soil, but the degradation was slower in other soils. If a thin layer of the pine forest humus was added on top of mineral sawmill soil, the original chlorophenol concentrations (high, ca. 70 μg g(-1), or moderate, ca. 20 μg g(-1)) in sawmill soil decreased by >40 % in 24 days. No degradation was noticed if the mineral soil was kept bare or if the covering humus soil layer was sterilized beforehand. Our results suggest that covering mineral soil with an organic soil layer is an efficient way to remediate recalcitrant chlorophenol contamination in mineral soils. The results of the field experiment are promising.

  18. [Spatial distribution prediction of surface soil Pb in a battery contaminated site].

    PubMed

    Liu, Geng; Niu, Jun-Jie; Zhang, Chao; Zhao, Xin; Guo, Guan-Lin

    2014-12-01

    In order to enhance the reliability of risk estimation and to improve the accuracy of pollution scope determination in a battery contaminated site with the soil characteristic pollutant Pb, four spatial interpolation models, including Combination Prediction Model (OK(LG) + TIN), kriging model (OK(BC)), Inverse Distance Weighting model (IDW), and Spline model were employed to compare their effects on the spatial distribution and pollution assessment of soil Pb. The results showed that Pb concentration varied significantly and the data was severely skewed. The variation coefficient of the site was higher in the local region. OK(LG) + TIN was found to be more accurate than the other three models in predicting the actual pollution situations of the contaminated site. The prediction accuracy of other models was lower, due to the effect of the principle of different models and datum feature. The interpolation results of OK(BC), IDW and Spline could not reflect the detailed characteristics of seriously contaminated areas, and were not suitable for mapping and spatial distribution prediction of soil Pb in this site. This study gives great contributions and provides useful references for defining the remediation boundary and making remediation decision of contaminated sites.

  19. Remediation of lead-contaminated soils

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Peters, R.W.; Shem, L.

    1992-01-01

    Excavation and transport of soil contaminated with heavy metals has generally been the standard remediation technique for treatment of heavy-metal-contaminated soils. This approach is not a permanent solution; moreover, off-site shipment and disposal of contaminated soil involves high expense, liability, and appropriate regulatory approval. Recently, a number of other techniques have been investigated for treating such contaminated sites, including flotation, solidification/stabilization, vitrification, and chemical extraction. This paper reports the results of a laboratory investigation determining the efficiency of using chelating agents to extract lead from contaminated soils. Lead concentrations in the soils ranged from 500 to 10,000 mg/kg. Ethylenediaminetetraacetic acidmore » (EDTA) and nitrilotriacetic acid (NTA) were examined for their potential extractive capabilities. Concentrations of the chelating agents ranged from 0.01 to 0.10 M. The pH of the suspensions in which the extractions were performed ranged from 4 to 12. Results showed that the removal of lead using NTA and water was ph-dependent, whereas the removal of lead using EDTA was ph-insensitive. Maximum removals of lead were 68.7%,19.1%, and 7.3% using EDTA, NTA, and water, respectively (as compared with initial lead concentrations).« less

  20. Remediation of lead-contaminated soils

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Peters, R.W.; Shem, L.

    1992-09-01

    Excavation and transport of soil contaminated with heavy metals has generally been the standard remediation technique for treatment of heavy-metal-contaminated soils. This approach is not a permanent solution; moreover, off-site shipment and disposal of contaminated soil involves high expense, liability, and appropriate regulatory approval. Recently, a number of other techniques have been investigated for treating such contaminated sites, including flotation, solidification/stabilization, vitrification, and chemical extraction. This paper reports the results of a laboratory investigation determining the efficiency of using chelating agents to extract lead from contaminated soils. Lead concentrations in the soils ranged from 500 to 10,000 mg/kg. Ethylenediaminetetraacetic acidmore » (EDTA) and nitrilotriacetic acid (NTA) were examined for their potential extractive capabilities. Concentrations of the chelating agents ranged from 0.01 to 0.10 M. The pH of the suspensions in which the extractions were performed ranged from 4 to 12. Results showed that the removal of lead using NTA and water was ph-dependent, whereas the removal of lead using EDTA was ph-insensitive. Maximum removals of lead were 68.7%,19.1%, and 7.3% using EDTA, NTA, and water, respectively (as compared with initial lead concentrations).« less

  1. Mechanochemical remediation of PCB contaminated soil.

    PubMed

    Wang, Haizhu; Hwang, Jisu; Huang, Jun; Xu, Ying; Yu, Gang; Li, Wenchao; Zhang, Kunlun; Liu, Kai; Cao, Zhiguo; Ma, Xiaohui; Wei, Zhipeng; Wang, Quhui

    2017-02-01

    Soil contaminated by polychlorinated biphenyls (PCBs) is a ubiquitous problem in the world, which can cause significant risks to human health and the environment. Mechanochemical destruction (MCD) has been recognized as a promising technology for the destruction of persistent organic pollutants (POPs) and other organic molecules in both solid waste and contaminated soil. However, few studies have been published about the application of MCD technology for the remediation of PCB contaminated soil. In the present study, the feasibility of destroying PCBs in contaminated soil by co-grinding with and without additives in a planetary ball mill was investigated. After 4 h milling time, more than 96% of PCBs in contaminated soil samples were destroyed. The residual concentrations of PCBs decreased from 1000 mg/kg to below the provisional Basel Convention limit of less than 50 mg/kg. PCDD/F present in the original soil at levels of 4200 ng TEQ/kg was also destroyed with even a slightly higher destruction efficiency. Only minor dechlorinations of the PCBs were observed and the destruction of the hydrocarbon skeleton is proposed as the main degradation pathway of PCBs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Sources and Practices Contributing to Soil Contamination

    Treesearch

    A.S. Knox; A.P. Gamerdinger; D.C. Adriano; R.K. Kolka; D.I. Kaplan

    1999-01-01

    The term soil contamination can have different connotations because anthropogehic sources of contaminants have affected virtually every natural ecosystem in the world; a commonly held view is that contamination occurs when the soil composition deiiates from the normal composition (Adriano et al., 1997). Other specialists have defined soil pollution as the presence of...

  3. Caresoil: A multidisciplinar Project to characterize, remediate, monitor and evaluate the risk of contaminated soils in Madrid (Spain)

    NASA Astrophysics Data System (ADS)

    Muñoz-Martín, Alfonso; Antón, Loreto; Granja, Jose Luis; Villarroya, Fermín; Montero, Esperanza; Rodríguez, Vanesa

    2016-04-01

    Soil contamination can come from diffuse sources (air deposition, agriculture, etc.) or local sources, these last being related to anthropogenic activities that are potentially soil contaminating activities. According to data from the EU, in Spain, and particularly for the Autonomous Community of Madrid, it can be considered that heavy metals, toxic organic compounds (including Non Aqueous Phases Liquids, NAPLs) and combinations of both are the main problem of point sources of soil contamination in our community. The five aspects that will be applied in Caresoil Program (S2013/MAE-2739) in the analysis and remediation of a local soil contamination are: 1) the location of the source of contamination and characterization of soil and aquifer concerned, 2) evaluation of the dispersion of the plume, 3) application of effective remediation techniques, 4) monitoring the evolution of the contaminated soil and 5) risk analysis throughout this process. These aspects involve advanced technologies (hydrogeology, geophysics, geochemistry,...) that require new developing of knowledge, being necessary the contribution of several researching groups specialized in the fields previously cited, as they are those integrating CARESOIL Program. Actually two cases concerning hydrocarbon spills, as representative examples of soil local contamination in Madrid area, are being studied. The first is being remediated and we are monitoring this process to evaluate its effectiveness. In the second location we are defining the extent of contamination in soil and aquifer to define the most effective remediation technique.

  4. Treatment of chromium contaminated soil using bioremediation

    NASA Astrophysics Data System (ADS)

    Purwanti, Ipung Fitri; Putri, Tesya Paramita; Kurniawan, Setyo Budi

    2017-11-01

    Chromium contamination in soil occurs due to the disposal of chromium industrial wastewater or sludge that excess the quality standard. Chromium concentration in soil is ranged between 1 to 300 mg/kg while the maximum health standard is 2.5 mg/kg. Bioremediation is one of technology that could be used for remediating heavy metal contamination in soil. Bacteria have an ability to remove heavy metal from soil. One bacteria species that capable to remove chromium from soil is Bacillus subtilis. The aim of this research was to know the chromium removal percentage in contaminated soil by Bacillus subtilis. Artificial chromium contaminated soil was used by mixing 425gram sand and chromium trichloride solution. Concentration of chromium added into the spiked soil were 50, 75, and 100 mg/L. During 14 days, pH, soil temperature and soil moisture were tested. Initial and final number of bacterial colony and chromium concentration analysed. The result showed that the highest percentage of chromium removal was 11% at a chromium concentration of 75 mg/L

  5. The tolerance efficiency of Panicum maximum and Helianthus annuus in TNT-contaminated soil and nZVI-contaminated soil.

    PubMed

    Jiamjitrpanich, Waraporn; Parkpian, Preeda; Polprasert, Chongrak; Laurent, François; Kosanlavit, Rachain

    2012-01-01

    This study was designed to compare the initial method for phytoremediation involving germination and transplantation. The study was also to determine the tolerance efficiency of Panicum maximum (Purple guinea grass) and Helianthus annuus (Sunflower) in TNT-contaminated soil and nZVI-contaminated soil. It was found that the transplantation of Panicum maximum and Helianthus annuus was more suitable than germination as the initiate method of nano-phytoremediation potting test. The study also showed that Panicum maximum was more tolerance than Helianthus annuus in TNT and nZVI-contaminated soil. Therefore, Panicum maximum in the transplantation method should be selected as a hyperaccumulated plant for nano-phytoremediation potting tests. Maximum tolerance dosage of Panicum maximum to TNT-concentration soil was 320 mg/kg and nZVI-contaminated soil was 1000 mg/kg in the transplantation method.

  6. Developing an integration tool for soil contamination assessment

    NASA Astrophysics Data System (ADS)

    Anaya-Romero, Maria; Zingg, Felix; Pérez-Álvarez, José Miguel; Madejón, Paula; Kotb Abd-Elmabod, Sameh

    2015-04-01

    In the last decades, huge soil areas have been negatively influenced or altered in multiples forms. Soils and, consequently, underground water, have been contaminated by accumulation of contaminants from agricultural activities (fertilizers and pesticides) industrial activities (harmful material dumping, sludge, flying ashes) and urban activities (hydrocarbon, metals from vehicle traffic, urban waste dumping). In the framework of the RECARE project, local partners across Europe are focusing on a wide range of soil threats, as soil contamination, and aiming to develop effective prevention, remediation and restoration measures by designing and applying targeted land management strategies (van Lynden et al., 2013). In this context, the Guadiamar Green Corridor (Southern Spain) was used as a case study, aiming to obtain soil data and new information in order to assess soil contamination. The main threat in the Guadiamar valley is soil contamination after a mine spill occurred on April 1998. About four hm3 of acid waters and two hm3 of mud, rich in heavy metals, were released into the Agrio and Guadiamar rivers affecting more than 4,600 ha of agricultural and pasture land. Main trace elements contaminating soil and water were As, Cd, Cu, Pb, Tl and Zn. The objective of the present research is to develop informatics tools that integrate soil database, models and interactive platforms for soil contamination assessment. Preliminary results were obtained related to the compilation of harmonized databases including geographical, hydro-meteorological, soil and socio-economic variables based on spatial analysis and stakeholder's consultation. Further research will be modellization and upscaling at the European level, in order to obtain a scientifically-technical predictive tool for the assessment of soil contamination.

  7. Contaminant gradients in trees: Directional tree coring reveals boundaries of soil and soil-gas contamination with potential applications in vapor intrusion assessment

    USGS Publications Warehouse

    Wilson, Jordan L.; Samaranayake, V.A.; Limmer, Matthew A.; Schumacher, John G.; Burken, Joel G.

    2017-01-01

    Contaminated sites pose ecological and human-health risks through exposure to contaminated soil and groundwater. Whereas we can readily locate, monitor, and track contaminants in groundwater, it is harder to perform these tasks in the vadose zone. In this study, tree-core samples were collected at a Superfund site to determine if the sample-collection location around a particular tree could reveal the subsurface location, or direction, of soil and soil-gas contaminant plumes. Contaminant-centroid vectors were calculated from tree-core data to reveal contaminant distributions in directional tree samples at a higher resolution, and vectors were correlated with soil-gas characterization collected using conventional methods. Results clearly demonstrated that directional tree coring around tree trunks can indicate gradients in soil and soil-gas contaminant plumes, and the strength of the correlations were directly proportionate to the magnitude of tree-core concentration gradients (spearman’s coefficient of -0.61 and -0.55 in soil and tree-core gradients, respectively). Linear regression indicates agreement between the concentration-centroid vectors is significantly affected by in-planta and soil concentration gradients and when concentration centroids in soil are closer to trees. Given the existing link between soil-gas and vapor intrusion, this study also indicates that directional tree coring might be applicable in vapor intrusion assessment.

  8. Contaminant Gradients in Trees: Directional Tree Coring Reveals Boundaries of Soil and Soil-Gas Contamination with Potential Applications in Vapor Intrusion Assessment.

    PubMed

    Wilson, Jordan L; Samaranayake, V A; Limmer, Matthew A; Schumacher, John G; Burken, Joel G

    2017-12-19

    Contaminated sites pose ecological and human-health risks through exposure to contaminated soil and groundwater. Whereas we can readily locate, monitor, and track contaminants in groundwater, it is harder to perform these tasks in the vadose zone. In this study, tree-core samples were collected at a Superfund site to determine if the sample-collection location around a particular tree could reveal the subsurface location, or direction, of soil and soil-gas contaminant plumes. Contaminant-centroid vectors were calculated from tree-core data to reveal contaminant distributions in directional tree samples at a higher resolution, and vectors were correlated with soil-gas characterization collected using conventional methods. Results clearly demonstrated that directional tree coring around tree trunks can indicate gradients in soil and soil-gas contaminant plumes, and the strength of the correlations were directly proportionate to the magnitude of tree-core concentration gradients (spearman's coefficient of -0.61 and -0.55 in soil and tree-core gradients, respectively). Linear regression indicates agreement between the concentration-centroid vectors is significantly affected by in planta and soil concentration gradients and when concentration centroids in soil are closer to trees. Given the existing link between soil-gas and vapor intrusion, this study also indicates that directional tree coring might be applicable in vapor intrusion assessment.

  9. Restoration of contaminated soils in abandoned mine areas (Tuscany, Italy)

    NASA Astrophysics Data System (ADS)

    Bini, Claudio; Wahsha, Mohammad

    2016-04-01

    In Italy ore research and exploitation have been nearly exhausted since the end of the last century, and have left on the land a huge amount of mine waste, therefore provoking evident environmental damage including surface and groundwater, soils, vegetation and the food chain, and a potential threat to human health. The main processes occurring at these sites are: rock disgregation, fragments migration, dust dispersion, oxidation (Eh>250mV), acidification (pH<7), hydrolisis and metal leaching, precipitation of oxides and sulphates. The restoration of these sites, therefore, is a primary objective, in order to reduce/eliminate the risk associated to the contamination sources of past activities, and the consequent environmental and human health hazard. The increasing environmental consciousness of general population compelled Public Administrators to set down effective legislation acts on this subject (e.g. D.L. 152/2006), and more generally on environmental contamination. In this work we present the results of a survey carried out at several mixed sulphides mine sites in Tuscany, exploited for at least a millennium, and closed in the last century. Biogeochemical analyses carried out on representative soil profiles (Spolic Technosols) and vegetation in the proximal and distal areas of ore exploitation show heavy metal concentrations (Cd, Cu, Fe, Pb, Zn) overcoming legislation limits on average. Ni, Cr and Mn concentrations, instead, are generally below the reference levels. The results obtained suggest that the abandoned mine sites represent actual natural laboratories where to experiment new opportunities for restoration of anthropogenically contaminated areas, and to study new pedogenetic trends from these peculiar parent materials. Moreover, plants growing on these substrates are genetically adapted to metal-enriched soils, and therefore may be utilized in phytoremediation of contaminated sites. Furthermore, the institution of natural parks in these areas could

  10. Humus-assisted cleaning of heavy metal contaminated soils

    NASA Astrophysics Data System (ADS)

    Borggaard, Ole K.; Rasmussen, Signe B.

    2016-04-01

    Contamination of soils with non-degradable heavy metals (HMs) because of human acticities is globally a serious problem threatening human health and ecosystem functioning. To avoid negative effects, HMs must be removed either on-site by plant uptake (phytoremediation) or off-site by extraction (soil washing). In both strategies, HM solubility must be augmented by means of a strong ligand (complexant). Often polycarboxylates such as EDTA and NTA are used but these ligands are toxic, synthetic (non-natural) and may promote HM leaching. Instead naturally occurring soluble humic substances (HS) were tested as means for cleaning HM contaminated soils; HS samples from beech and spruce litter, compost percolate and processed cow slurry were tested. Various long-term HM contaminated soils were extracted with solutions of EDTA, NTA or HS at different pH by single-step and multiple-step extraction mode. The results showed that each of the three complexant types increased HM solubility but the pH-dependent HM extraction efficiency decreased in the order: EDTA ≈ NTA > HS. However, the naturally occurring HS seems suitable for cleaning As, Cd, Cu and Zn contaminated soils both in relation to phytoremediation of moderately contaminated soils and washing of strongly contaminated soils. On the other hand, HS was found unsuited as cleaning agent for Pb polluted calcareous soils. If future field experiments confirm these laboratory results, we have a new cheap and environmentally friendly method for solving a great pollution problem, i.e. cleaning of heavy metal contaminated soils. In addition, humic substances possess additional benefits such as improving soil structure and stimulating microbial activity.

  11. Bioremediation potential of diesel-contaminated Libyan soil.

    PubMed

    Koshlaf, Eman; Shahsavari, Esmaeil; Aburto-Medina, Arturo; Taha, Mohamed; Haleyur, Nagalakshmi; Makadia, Tanvi H; Morrison, Paul D; Ball, Andrew S

    2016-11-01

    Bioremediation is a broadly applied environmentally friendly and economical treatment for the clean-up of sites contaminated by petroleum hydrocarbons. However, the application of this technology to contaminated soil in Libya has not been fully exploited. In this study, the efficacy of different bioremediation processes (necrophytoremediation using pea straw, bioaugmentation and a combination of both treatments) together with natural attenuation were assessed in diesel contaminated Libyan soils. The addition of pea straw was found to be the best bioremediation treatment for cleaning up diesel contaminated Libyan soil after 12 weeks. The greatest TPH degradation, 96.1% (18,239.6mgkg(-1)) and 95% (17,991.14mgkg(-1)) were obtained when the soil was amended with pea straw alone and in combination with a hydrocarbonoclastic consortium respectively. In contrast, natural attenuation resulted in a significantly lower TPH reduction of 76% (14,444.5mgkg(-1)). The presence of pea straw also led to a significant increased recovery of hydrocarbon degraders; 5.7log CFU g(-1) dry soil, compared to 4.4log CFUg(-1) dry soil for the untreated (natural attenuation) soil. DGGE and Illumina 16S metagenomic analyses confirm shifts in bacterial communities compared with original soil after 12 weeks incubation. In addition, metagenomic analysis showed that original soil contained hydrocarbon degraders (e.g. Pseudoxanthomonas spp. and Alcanivorax spp.). However, they require a biostimulant (in this case pea straw) to become active. This study is the first to report successful oil bioremediation with pea straw in Libya. It demonstrates the effectiveness of pea straw in enhancing bioremediation of the diesel-contaminated Libyan soil. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. SOIL WASHING TREATABILITY TESTS FOR PESTICIDE- CONTAMINATED SOIL

    EPA Science Inventory

    The 1987 Sand Creek Operable Unit 5 record of decision (ROD) identified soil washing as the selected technology to remediate soils contaminated with high levels of organochlorine pesticides, herbicides, and metals. Initial treatability tests conducted to assess the applicability...

  13. In situ removal of contamination from soil

    DOEpatents

    Lindgren, Eric R.; Brady, Patrick V.

    1997-01-01

    A process of remediation of cationic heavy metal contamination from soil utilizes gas phase manipulation to inhibit biodegradation of a chelating agent that is used in an electrokinesis process to remove the contamination, and further gas phase manipulation to stimulate biodegradation of the chelating agent after the contamination has been removed. The process ensures that the chelating agent is not attacked by bioorganisms in the soil prior to removal of the contamination, and that the chelating agent does not remain as a new contaminant after the process is completed.

  14. In situ removal of contamination from soil

    DOEpatents

    Lindgren, E.R.; Brady, P.V.

    1997-10-14

    A process of remediation of cationic heavy metal contamination from soil utilizes gas phase manipulation to inhibit biodegradation of a chelating agent that is used in an electrokinesis process to remove the contamination. The process also uses further gas phase manipulation to stimulate biodegradation of the chelating agent after the contamination has been removed. The process ensures that the chelating agent is not attacked by bioorganisms in the soil prior to removal of the contamination, and that the chelating agent does not remain as a new contaminant after the process is completed. 5 figs.

  15. Bioremediation of petroleum-contaminated soil: A Review

    NASA Astrophysics Data System (ADS)

    Yuniati, M. D.

    2018-02-01

    Petroleum is the major source of energy for various industries and daily life. Releasing petroleum into the environment whether accidentally or due to human activities is a main cause of soil pollution. Soil contaminated with petroleum has a serious hazard to human health and causes environmental problems as well. Petroleum pollutants, mainly hydrocarbon, are classified as priority pollutants. The application of microorganisms or microbial processes to remove or degrade contaminants from soil is called bioremediation. This microbiological decontamination is claimed to be an efficient, economic and versatile alternative to physicochemical treatment. This article presents an overview about bioremediation of petroleum-contaminated soil. It also includes an explanation about the types of bioremediation technologies as well as the processes.

  16. The activation energy of stabilised/solidified contaminated soils.

    PubMed

    Chitambira, B; Al-Tabbaa, A; Perera, A S R; Yu, X D

    2007-03-15

    Developing an understanding of the time-related performance of cement-treated materials is essential in understanding their durability and long-term effectiveness. A number of models have been developed to predict this time-related performance. One such model is the maturity concept which involves use of the 'global' activation energy which derives from the Arrhenius equation. The accurate assessment of the activation energy is essential in the realistic modelling of the accelerated ageing of cement-treated soils. Experimentally, this model is applied to a series of tests performed at different elevated temperatures. Experimental work, related to the results of a time-related performance on a contaminated site in the UK treated with in situ stabilisation/solidification was carried out. Three different cement-based grouts were used on two model site soils which were both contaminated with a number of heavy metals and a hydrocarbon. Uncontaminated soils were also tested. Elevated temperatures up to 60 degrees C and curing periods up to 90 days were used. The resulting global activation energies for the uncontaminated and contaminated soils were compared. Lower values were obtained for the contaminated soils reflecting the effect of the contaminants. The resulting equivalent ages for the uncontaminated and contaminated mixes tested were 5.1-7.4 and 0.8-4.1 years, respectively. This work shows how a specific set of contaminants affect the E(a) values for particular cementitious systems and how the maturity concept can be applied to cement-treated contaminated soils.

  17. Effect Of Soil Properties On The Geochemical Speciation Of Arsenic In Contaminated Soils: A Greenhouse Study

    NASA Astrophysics Data System (ADS)

    Sharma, S.; Sarkar, D.; Datta, R.

    2005-05-01

    Land-applied arsenical pesticides have contributed elevated soil arsenic (As) levels. Many baseline risk assessments As-contaminated sites assume that all As present in the soil is bioavailable, thereby potentially overestimating the actual health risk. However, risk from As exposure is associated only with those forms of As that are potentially extractable by the human gastrointestinal juices. It has been demonstrated that As may exist in several geochemical forms depending on soil chemical properties, which may or may not be bioavailable. The current study aims at addressing the issue of soil variability on As bioavailability as a function of soil physico-chemical properties in a greenhouse setting involving dynamic interactions between soil, water and plants. Four different soils were chosen based on their potential differences with respect to As reactivity: Immokalee, an acid sand with low extractable Fe/Al, having minimal arsenic retention capacity; Millhopper, an acid sandy loam with high extractable Fe/Al oxides; Pahokee Muck soil with 85% soil organic matter (SOM) as well as high Fe/Al content; and Orelia soil with high clay and Fe/Al content. Soils were amended with sodium arsenate (675 and 1500 mg/Kg). Rice (Oryza sativa) was used as the test crop. A sequential extraction scheme was employed to identify the geochemical forms of As in soils (soluble, exchangeable, organic, Fe/Al-bound, Ca/Mg-bound, residual) immediately after spiking; after 3 mo; and after 6 mo of equilibration time. Concentrations of these As forms were correlated with the in-vitro bioavailable As fractions to identify those As fractions that are most likely to be bioavailable. Results from this study showed that there was little to no plant growth in the contaminated soils. Sequential extractions of the soil indicated that arsenic is strongly adsorbed onto soil amorphous iron/aluminum oxides, and the degree of arsenic retention is a direct function of equilibration time.

  18. Bioremediation of lead contaminated soil with Rhodobacter sphaeroides.

    PubMed

    Li, Xiaomin; Peng, Weihua; Jia, Yingying; Lu, Lin; Fan, Wenhong

    2016-08-01

    Bioremediation with microorganisms is a promising technique for heavy metal contaminated soil. Rhodobacter sphaeroides was previously isolated from oil field injection water and used for bioremediation of lead (Pb) contaminated soil in the present study. Based on the investigation of the optimum culturing conditions and the tolerance to Pb, we employed the microorganism for the remediation of Pb contaminated soil simulated at different contamination levels. It was found that the optimum temperature, pH, and inoculum size for R. sphaeroides is 30-35 °C, 7, and 2 × 10(8) mL(-1), respectively. Rhodobacter sphaeroides did not remove the Pb from soil but did change its speciation. During the bioremediation process, more available fractions were transformed to less accessible and inert fractions; in particular, the exchangeable phase was dramatically decreased while the residual phase was substantially increased. A wheat seedling growing experiment showed that Pb phytoavailability was reduced in amended soils. Results inferred that the main mechanism by which R. sphaeroides treats Pb contaminated soil is the precipitation formation of inert compounds, including lead sulfate and lead sulfide. Although the Pb bioremediation efficiency on wheat was not very high (14.78% root and 24.01% in leaf), R. sphaeroides remains a promising alternative for Pb remediation in contaminated soil. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Screening of plants for phytoremediation of oil-contaminated soil.

    PubMed

    Ikeura, Hiromi; Kawasaki, Yu; Kaimi, Etsuko; Nishiwaki, Junko; Noborio, Kosuke; Tamaki, Masahiko

    2016-01-01

    Several species of ornamental flowering plants were evaluated regarding their phytoremediation ability for the cleanup of oil-contaminated soil in Japanese environmental conditions. Thirty-three species of plants were grown in oil-contaminated soil, and Mimosa, Zinnia, Gazania, and cypress vine were selected for further assessment on the basis of their favorable initial growth. No significant difference was observed in the above-ground and under-ground dry matter weight of Gazania 180 days after sowing between contaminated and non-contaminated plots. However, the other 3 species of plants died by the 180th day, indicating that Gazania has an especially strong tolerance for oil-contaminated soil. The total petroleum hydrocarbon concentration of the soils in which the 4 species of plants were grown decreased by 45-49% by the 180th day. Compared to an irrigated plot, the dehydrogenase activity of the contaminated soil also increased significantly, indicating a phytoremediation effect by the 4 tested plants. Mimosa, Zinnia, and cypress vine all died by the 180th day after seeding, but the roots themselves became a source of nutrients for the soil microorganisms, which led to a phytoremediation effect by increase in the oil degradation activity. It has been indicated that Gazania is most appropriate for phytoremediation of oil-contaminated soil.

  20. Advances on the determination of thresholds of Cu phytotoxicity in field-contaminated soils in central Chile.

    PubMed

    Mondaca, Pedro; Catrin, Joanie; Verdejo, José; Sauvé, Sébastien; Neaman, Alexander

    2017-04-01

    To better determine phytotoxicity thresholds for metals in the soil, studies should use actual field-contaminated soil samples rather than metal-spiked soil preparations. However, there are surprisingly few such data available for Cu phytotoxicity in field-contaminated soils. Moreover, these studies differ from each other with regards to soil characteristics and experimental setups. This study aimed at more accurately estimating Cu phytotoxicity thresholds using field-collected agricultural soils (Entisols) from areas exposed to contamination from Cu mining. For this purpose, the exposure to Cu was assessed by measuring total soil Cu, soluble Cu, free Cu 2+ activity, and Cu in the plant aerial tissues. On the other hand, two bioassay durations (short-term and long-term), three plant species (Avena sativa L., Brassica rapa CrGC syn. Rbr, and Lolium perenne L.), and five biometric endpoints (shoot length and weight, root length and weight, and number of seed pods) were considered. Overall plant growth was best predicted by total Cu content of the soil. Despite some confounding factors, it was possible to determine EC 10 , EC 25 and EC 50 of total Cu in the soil. Brassica rapa was more sensitive than Avena sativa for all endpoints, while Lolium perenne was of intermediate sensitivity. For the short-term bioassay (21 days for all three species), the averaged EC 10 , EC 25 and EC 50 values of total soil Cu (in mg kg -1 ) were 356, 621, and 904, respectively. For the long-term bioassay (62 days for oat and 42 days for turnip), the averaged EC 10 , EC 25 and EC 50 values of total soil Cu (in mg kg -1 ) were 355, 513, and 688, respectively. The obtained results indicate that chronic test is a suitable method for assessing Cu phytotoxicity in field-contaminated soils. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Soil geochemical factors regulate Cd accumulation by metal hyperaccumulating Noccaea caerulescens (J. Presl & C. Presl) F.K. Mey in field-contaminated soils.

    PubMed

    Rosenfeld, Carla E; Chaney, Rufus L; Martínez, Carmen E

    2018-03-01

    Cadmium contamination in soil is a substantial global problem, and of significant concern due to high food-chain transfer. Cadmium hyperaccumulators are of particular interest because of their ability to tolerate and take up significant amounts of heavy metal pollution from soils. One particular plant, Noccaea caerulescens (formerly, Thlaspi caerulescens), has been extensively studied in terms of its capacity to accumulate heavy metals (specifically Zn and Cd), though these studies have primarily utilized hydroponic and metal-spiked model soil systems. We studied Cd and nutrient uptake by two N. caerulescens ecotypes, Prayon (Zn-only hyperaccumulator) and Ganges (Zn- and Cd-hyperaccumulator) in four long-term field-contaminated soils. Our data suggest that individual soil properties such as total soil Cd, Zn:Cd molar ratio, or soil pH do not accurately predict Cd uptake by hyperaccumulating plants. Additionally, total Cd uptake by the hyperaccumulating Ganges ecotype was substantially less than its physiological capacity, which is likely due to Cd-containing solid phases (primarily iron oxides) and pH that play an important role in regulating and limiting Cd solubility. Increased P accumulation in the Ganges leaves, and greater plant Fe accumulation from Cd-containing soils suggests that rhizosphere alterations via proton, and potentially organic acid, secretion may also play a role in nutrient and Cd acquisition by the plant roots. The current study highlights the role that soil geochemical factors play in influencing Cd uptake by hyperaccumulating plants. While these plants may have high physiological potential to accumulate metals from contaminated soils, individual soil geochemical factors and the plant-soil interactions in that soil will dictate the actual amount of phytoextractable metal. This underlines the need for site-specific understanding of metal-containing solid phases and geochemical properties of soils before undertaking phytoextraction efforts

  2. Bioremediation of soil contaminated crude oil by Agaricomycetes.

    PubMed

    Mohammadi-Sichani, M Maryam; Assadi, M Mazaheri; Farazmand, A; Kianirad, M; Ahadi, A M; Ghahderijani, H Hadian

    2017-01-01

    One of the most important environmental problems is the decontamination of petroleum hydrocarbons polluted soil, particularly in the oil-rich country. Bioremediation is the most effective way to remove these pollutants in the soil. Spent mushroom compost has great ability to decompose lignin-like pollution. The purpose of this study was the bioremediation of soil contaminated with crude oil by an Agaricomycetes . Soil sample amended with spent mushroom compost into 3%, 5% and 10% (w/w) with or without fertilizer. Ecotoxicity germination test was conducted with Lipidium sativa . The amplified fragment (18 s rDNA) sequence of this mushroom confirmed that the strain belonged to Pleurotus ostreatus species with complete homology (100% identity). All tests experiment sets were effective at supporting the degradation of petroleum hydrocarbons contaminated soil after three months. Petroleum contaminated soil amended with Spent mushroom compost 10% and fertilizer removed 64.7% of total petroleum hydrocarbons compared control. The germination index (%) in ecotoxicity tests ranged from 60.4 to 93.8%. This showed that the petroleum hydrocarbons contaminated soil amended with 10% Spent mushroom compost had higher bioremediation ability and reduced soil toxicity in less than three months.

  3. Phytoextraction potential of poplar (Populus alba L. var. pyramidalis Bunge) from calcareous agricultural soils contaminated by cadmium.

    PubMed

    Hu, Yahu; Nan, Zhongren; Jin, Cheng; Wang, Ning; Luo, Huanzhang

    2014-01-01

    To investigate the phytoextraction potential of Populus alba L. var. pyramidalis Bunge for cadmium (Cd) contaminated calcareous soils, a concentration gradient experiment and a field sampling experiment (involving poplars of different ages) were conducted. The translocation factors for all experiments and treatments were greater than 1. The bioconcentration factor decreased from 2.37 to 0.25 with increasing soil Cd concentration in the concentration gradient experiment and generally decreased with stand age under field conditions. The Cd concentrations in P. pyramidalis organs decreased in the order of leaves > stems > roots. The shoot biomass production in the concentration gradient experiment was not significantly reduced with soil Cd concentrations up to or slightly over 50 mg kg(-1). The results show that the phytoextraction efficiency of P. pyramidalis depends on both the soil Cd concentration and the tree age. Populus pyramidalis is most suitable for remediation of slightly Cd contaminated calcareous soils through the combined harvest of stems and leaves under actual field conditions.

  4. Biochar- and phosphate-induced immobilization of heavy metals in contaminated soil and water: implication on simultaneous remediation of contaminated soil and groundwater.

    PubMed

    Liang, Yuan; Cao, Xinde; Zhao, Ling; Arellano, Eduardo

    2014-03-01

    Long-term wastewater irrigation or solid waste disposal has resulted in the heavy metal contamination in both soil and groundwater. It is often separately implemented for remediation of contaminated soil or groundwater at a specific site. The main objective of this study was to demonstrate the hypothesis of simultaneous remediation of both heavy metal contaminated soil and groundwater by integrating the chemical immobilization and pump-and-treat methods. To accomplish the objective, three experiments were conducted, i.e., an incubation experiment was first conducted to determine how dairy-manure-derived biochar and phosphate rock tailing induced immobilization of Cd in the Cd-contaminated soils; second, a batch sorption experiment was carried out to determine whether the pre-amended contaminated soil still had the ability to retain Pb, Zn and Cd from aqueous solution. BCR sequential extraction as well as XRD and SEM analysis were conducted to explore the possible retention mechanism; and last, a laboratory-scale model test was undertaken by leaching the Pb, Zn, and Cd contaminated groundwater through the pre-amended contaminated soils to demonstrate how the heavy metals in both contaminated soil and groundwater were simultaneously retained and immobilized. The incubation experiment showed that the phosphate biochar were effective in immobilizing soil Cd with Cd concentration in TCLP (toxicity characteristics leaching procedure) extract reduced by 19.6 % and 13.7 %, respectively. The batch sorption experiment revealed that the pre-amended soil still had ability to retain Pb, Zn, and Cd from aqueous solution. The phosphate-induced metal retention was mainly due to the metal-phosphate precipitation, while both sorption and precipitation were responsible for the metal stabilization in the biochar amendment. The laboratory-scale test demonstrated that the soil amended with phosphate removed groundwater Pb, Zn, and Cd by 96.4 %, 44.6 %, and 49.2 %, respectively, and the

  5. Role of soil rhizobacteria in phytoremediation of heavy metal contaminated soils*

    PubMed Central

    Jing, Yan-de; He, Zhen-li; Yang, Xiao-e

    2007-01-01

    Heavy metal pollution of soil is a significant environmental problem and has its negative impact on human health and agriculture. Rhizosphere, as an important interface of soil and plant, plays a significant role in phytoremediation of contaminated soil by heavy metals, in which, microbial populations are known to affect heavy metal mobility and availability to the plant through release of chelating agents, acidification, phosphate solubilization and redox changes, and therefore, have potential to enhance phytoremediation processes. Phytoremediation strategies with appropriate heavy metal-adapted rhizobacteria have received more and more attention. This article paper reviews some recent advances in effect and significance of rhizobacteria in phytoremediation of heavy metal contaminated soils. There is also a need to improve our understanding of the mechanisms involved in the transfer and mobilization of heavy metals by rhizobacteria and to conduct research on the selection of microbial isolates from rhizosphere of plants growing on heavy metal contaminated soils for specific restoration programmes. PMID:17323432

  6. Soil Contamination and Remediation Strategies. Current research and future challenge

    NASA Astrophysics Data System (ADS)

    Petruzzelli, G.

    2012-04-01

    Soil contamination: the heritage of industrial development Contamination is only a part of a whole set of soil degradation processes, but it is one of paramount importance since soil pollution greatly influences the quality of water, food and human health. Soil contamination has been identified as an important issue for action in the European strategy for soil protection, it has been estimated that 3.5 million of sites are potentially contaminated in Europe. Contaminated soils have been essentially discovered in industrial sites landfills and energy production plants, but accumulation of heavy metals and organic compounds can be found also in agricultural land . Remediation strategies. from incineration to bioremediation The assessment of soil contamination is followed by remedial action. The remediation of contaminated soils started using consolidates technologies (incineration inertization etc.) previously employed in waste treatment,. This has contributed to consider a contaminated soil as an hazardous waste. This rough approximation was unfortunately transferred in many legislations and on this basis soil knowledge have been used only marginally in the clean up procedures. For many years soil quality has been identified by a value of concentration of a contaminant and excavation and landfill disposal of soil has been largely used. In the last years the knowledge of remediation technology has rapidly grown, at present many treatment processes appear to be really feasible at field scale, and soil remediation is now based on risk assessment procedures. Innovative technologies, largely dependent on soil properties, such as in situ chemical oxidation, electroremediation, bioventing, soil vapor extraction etc. have been successfully applied. Hazardous organic compounds are commonly treated by biological technologies, biorememdiation and phytoremediation, being the last partially applied also for metals. Technologies selection is no longer exclusively based on

  7. MEMBRANE TECHNOLOGIES FOR REMEDIATING CONTAMINATED SOILS: A CRITICAL REVIEW

    EPA Science Inventory

    Regulatory compliance requires the cleanup of soils contaminated with toxic organic and metallic compounds. Several chemical and thermal detoxification technologies have been tested on soils excavated from contaminated sites. Soil washing with aqueous solutions transfers the cont...

  8. Remediation of sandy soils contaminated with hydrocarbons and halogenated hydrocarbons by soil vapour extraction.

    PubMed

    Albergaria, José Tomás; Alvim-Ferraz, Maria da Conceição M; Delerue-Matos, Cristina

    2012-08-15

    This paper presents the study of the remediation of sandy soils containing six of the most common contaminants (benzene, toluene, ethylbenzene, xylene, trichloroethylene and perchloroethylene) using soil vapour extraction (SVE). The influence of soil water content on the process efficiency was evaluated considering the soil type and the contaminant. For artificially contaminated soils with negligible clay contents and natural organic matter it was concluded that: (i) all the remediation processes presented efficiencies above 92%; (ii) an increase of the soil water content led to a more time-consuming remediation; (iii) longer remediation periods were observed for contaminants with lower vapour pressures and lower water solubilities due to mass transfer limitations. Based on these results an easy and relatively fast procedure was developed for the prediction of the remediation times of real soils; 83% of the remediation times were predicted with relative deviations below 14%. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Soil contamination with cadmium, consequences and remediation using organic amendments.

    PubMed

    Khan, Muhammad Amjad; Khan, Sardar; Khan, Anwarzeb; Alam, Mehboob

    2017-12-01

    Cadmium (Cd) contamination of soil and food crops is a ubiquitous environmental problem that has resulted from uncontrolled industrialization, unsustainable urbanization and intensive agricultural practices. Being a toxic element, Cd poses high threats to soil quality, food safety, and human health. Land is the ultimate source of waste disposal and utilization therefore, Cd released from different sources (natural and anthropogenic), eventually reaches soil, and then subsequently bio-accumulates in food crops. The stabilization of Cd in contaminated soil using organic amendments is an environmentally friendly and cost effective technique used for remediation of moderate to high contaminated soil. Globally, substantial amounts of organic waste are generated every day that can be used as a source of nutrients, and also as conditioners to improve soil quality. This review paper focuses on the sources, generation, and use of different organic amendments to remediate Cd contaminated soil, discusses their effects on soil physical and chemical properties, Cd bioavailability, plant uptake, and human health risk. Moreover, it also provides an update of the most relevant findings about the application of organic amendments to remediate Cd contaminated soil and associated mechanisms. Finally, future research needs and directions for the remediation of Cd contaminated soil using organic amendments are discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. System for the removal of contaminant soil-gas vapors

    DOEpatents

    Weidner, Jerry R.; Downs, Wayne C.; Kaser, Timothy G.; Hall, H. James

    1997-01-01

    A system extracts contaminated vapors from soil or other subsurface regions by using changes in barometric pressure to operate sensitive check valves that control air entry and removal from wells in the ground. The system creates an efficient subterranean flow of air through a contaminated soil plume and causes final extraction of the contaminants from the soil to ambient air above ground without any external energy sources.

  11. Phytoremediation of soils contaminated by cadmium

    NASA Astrophysics Data System (ADS)

    Watai, H.; Miyazaki, T.; Fujikawa, T.; Mizoguchi, M.

    2004-12-01

    Phytoremediation is a technique to clean up soils contaminated with heavy metals. Advantages of this method are that (1) This technique is suitable to cleanup soils slightly contaminated with heavy metals in relatively wide area. (2) The expense for clean up is lower than civil engineering techniques. (3) This method can remove heavy metals fundamentally from contaminated. (4) The heavy metals are able to recycle by ashing of plants. Many researches have been done on the phytoremediation up to now, but almost all these researches were devoted to clarify the phytoremediation from the view point of plants themselves. However, few efforts have been devoted to analyze the migrations of heavy metals in soils during the phytoremediation process. The objective of this study is to clarify the features of Cd migration when plant roots are absorbing Cd from the ambient soils. Especially, we focused on finding the Cd migration pattern by changing the soil condition such as plant growing periods, planting densities, and the initial Cd concentration in soils. We planted sunflowers in columns filled with Cd contaminated soils because sunflower is a well-known hyperaccumulator of Cd from soils. By cutting the shoots of plants at the soil surface, and by keeping the plant roots in the soils without disturbance, the Cd concentrations, moisture contents, pH distributions, EC distributions, and dry weight of residual roots in the soils were carefully analyzed. The experimental results showed that (1)The growth of the planted sunflowers were suffered by applying of Cd. (2)The decrease of suction was affected by water uptake by roots at the depth from 0 to 5 cm. Water contents with plants in soils decrease more than without plants. (3)Cd adsorption by roots was predominant within 5cm from soil surface. In addition, it was also shown that there was an optimal Cd concentration where Cd is most effectively adsorbed by the plant. In this experiment we found that 40 to 60 mg kg-1 was the

  12. Effects of poultry manure on soil biochemical properties in phthalic acid esters contaminated soil.

    PubMed

    Gao, Jun; Qin, Xiaojian; Ren, Xuqin; Zhou, Haifeng

    2015-12-01

    This study aimed to evaluate the effects of poultry manure (PM) on soil biological properties in DBP- and DEHP-contaminated soils. An indoor incubation experiment was conducted. Soil microbial biomass C (Cmic), soil enzymatic activities, and microbial phospholipid fatty acid (PLFA) concentrations were measured during incubation period. The results indicated that except alkaline phosphatase activity, DBP and DEHP had negative effects on Cmic, dehydrogenase, urease, protease activities, and contents of total PLFA. However, 5 % PM treatment alleviated the negative effects of PAEs on the above biochemical parameters. In DBP-contaminated soil, 5 % PM amendment even resulted in dehydroenase activity and Cmic content increasing by 17.8 and 11.8 % on the day 15 of incubation, respectively. During the incubation periods, the total PLFA contents decreased maximumly by 17.2 and 11.6 % in DBP- and DEHP-contaminated soils without PM amendments, respectively. Compared with those in uncontaminated soil, the total PLFA contents increased slightly and the value of bacPLFA/fugalPLFA increased significantly in PAE-contaminated soils with 5 % PM amendment. Nevertheless, in both contaminated soils, the effects of 5 % PM amendment on the biochemical parameters were not observed with 10 % PM amendment. In 10 % PM-amended soils, DBP and DEHP had little effect on Cmic, soil enzymatic activities, and microbial community composition. At the end of incubation, the effects of PAEs on these parameters disappeared, irrespective of PM amendment. The application of PM ameliorated the negative effect of PAEs on soil biological environment. However, further work is needed to study the effect of PM on soil microbial gene expression in order to explain the change mechanisms of soil biological properties.

  13. Biological technologies for the remediation of co-contaminated soil.

    PubMed

    Ye, Shujing; Zeng, Guangming; Wu, Haipeng; Zhang, Chang; Dai, Juan; Liang, Jie; Yu, Jiangfang; Ren, Xiaoya; Yi, Huan; Cheng, Min; Zhang, Chen

    2017-12-01

    Compound contamination in soil, caused by unreasonable waste disposal, has attracted increasing attention on a global scale, particularly since multiple heavy metals and/or organic pollutants are entering natural ecosystem through human activities, causing an enormous threat. The remediation of co-contaminated soil is more complicated and difficult than that of single contamination, due to the disparate remediation pathways utilized for different types of pollutants. Several modern remediation technologies have been developed for the treatment of co-contaminated soil. Biological remediation technologies, as the eco-friendly methods, have received widespread concern due to soil improvement besides remediation. This review summarizes the application of biological technologies, which contains microbial technologies (function microbial remediation and composting or compost addition), biochar, phytoremediation technologies, genetic engineering technologies and biochemical technologies, for the remediation of co-contaminated soil with heavy metals and organic pollutants. Mechanisms of these technologies and their remediation efficiencies are also reviewed. Based on this study, this review also identifies the future research required in this field.

  14. System for the removal of contaminant soil-gas vapors

    DOEpatents

    Weidner, J.R.; Downs, W.C.; Kaser, T.G.; Hall, H.J.

    1997-12-16

    A system extracts contaminated vapors from soil or other subsurface regions by using changes in barometric pressure to operate sensitive check valves that control air entry and removal from wells in the ground. The system creates an efficient subterranean flow of air through a contaminated soil plume and causes final extraction of the contaminants from the soil to ambient air above ground without any external energy sources. 4 figs.

  15. Biosurfactant technology for remediation of cadmium and lead contaminated soils.

    PubMed

    Juwarkar, Asha A; Nair, Anupa; Dubey, Kirti V; Singh, S K; Devotta, Sukumar

    2007-08-01

    This research focuses on column experiments conducted to evaluate the potential of environmentally compatible rhamnolipid biosurfactant produced by Pseudomonas aeruginosa strain BS2 to remove heavy metals (Cd and Pb) from artificially contaminated soil. Results have shown that di-rhamnolipid removes not only the leachable or available fraction of Cd and Pb but also the bound metals as compared to tap water which removed the mobile fraction only. Washing of contaminated soil with tap water revealed that approximately 2.7% of Cd and 9.8% of Pb in contaminated soil was in freely available or weakly bound forms whereas washing with rhamnolipid removed 92% of Cd and 88% of Pb after 36 h of leaching. This indicated that di-rhamnolipid selectively favours mobilization of metals in the order of Cd>Pb. Biosurfactant specificity observed towards specific metal will help in preferential elution of specific contaminant using di-rhamnolipid. It was further observed that pH of the leachates collected from heavy metal contaminated soil column treated with di-rhamnolipid solution was low (6.60-6.78) as compared to that of leachates from heavy metal contaminated soil column treated with tap water (pH 6.90-7.25), which showed high dissolution of metal species from the contaminated soil and effective leaching of metals with treatment with biosurfactant. The microbial population of the contaminated soil was increased after removal of metals by biosurfactant indicating the decrease of toxicity of metals to soil microflora. This study shows that biosurfactant technology can be an effective and nondestructive method for bioremediation of cadmium and lead contaminated soil.

  16. Method for treatment of soils contaminated with organic pollutants

    DOEpatents

    Wickramanayake, Godage B.

    1993-01-01

    A method for treating soil contaminated by organic compounds wherein an ozone containing gas is treated with acid to increase the stability of the ozone in the soil environment and the treated ozone applied to the contaminated soil to decompose the organic compounds. The soil may be treated in situ or may be removed for treatment and refilled.

  17. Removal of residual contaminants in petroleum-contaminated soil by Fenton-like oxidation.

    PubMed

    Lu, Mang; Zhang, Zhongzhi; Qiao, Wei; Guan, Yueming; Xiao, Meng; Peng, Chong

    2010-07-15

    The degradation of bioremediation residues by hydrogen peroxide in petroleum-contaminated soil was investigated at circumneutral pH using a Fenton-like reagent (ferric ion chelated with EDTA). Batch tests were done on 20 g soil suspended in 60 mL aqueous solution containing hydrogen peroxide and Fe(3+)-EDTA complex under constant stirring. A slurry reactor was used to treat the soil based on the optimal reactant conditions. Contaminants were characterized by Fourier transform infrared spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry. The results showed that the optimal treatment condition was: the molar ratio of hydrogen peroxide to iron=200:1, and pH 7.0. Under the optimum condition, total dichloromethane-extractable organics were reduced from 14,800 to 2300 mg kg(-1) soil when the accumulative H(2)O(2) dosage was 2.45 mol kg(-1) soil during the reactor treatment. Abundance of viable cells was lower in incubated Fenton-like treated soil than in untreated soil. Oxidation of contaminants produced remarkable compositional and structural modifications. A fused ring compound, identified as C(34)H(38)N(1), was found to exhibit the greatest resistance to oxidation. 2010 Elsevier B.V. All rights reserved.

  18. Sensitivity analyses of a colloid-facilitated contaminant transport model for unsaturated heterogeneous soil conditions.

    NASA Astrophysics Data System (ADS)

    Périard, Yann; José Gumiere, Silvio; Rousseau, Alain N.; Caron, Jean

    2013-04-01

    Certain contaminants may travel faster through soils when they are sorbed to subsurface colloidal particles. Indeed, subsurface colloids may act as carriers of some contaminants accelerating their translocation through the soil into the water table. This phenomenon is known as colloid-facilitated contaminant transport. It plays a significant role in contaminant transport in soils and has been recognized as a source of groundwater contamination. From a mechanistic point of view, the attachment/detachment of the colloidal particles from the soil matrix or from the air-water interface and the straining process may modify the hydraulic properties of the porous media. Šimůnek et al. (2006) developed a model that can simulate the colloid-facilitated contaminant transport in variably saturated porous media. The model is based on the solution of a modified advection-dispersion equation that accounts for several processes, namely: straining, exclusion and attachement/detachement kinetics of colloids through the soil matrix. The solutions of these governing, partial differential equations are obtained using a standard Galerkin-type, linear finite element scheme, implemented in the HYDRUS-2D/3D software (Šimůnek et al., 2012). Modeling colloid transport through the soil and the interaction of colloids with the soil matrix and other contaminants is complex and requires the characterization of many model parameters. In practice, it is very difficult to assess actual transport parameter values, so they are often calibrated. However, before calibration, one needs to know which parameters have the greatest impact on output variables. This kind of information can be obtained through a sensitivity analysis of the model. The main objective of this work is to perform local and global sensitivity analyses of the colloid-facilitated contaminant transport module of HYDRUS. Sensitivity analysis was performed in two steps: (i) we applied a screening method based on Morris' elementary

  19. Phytotoxicity of trace metals in spiked and field-contaminated soils: Linking soil-extractable metals with toxicity.

    PubMed

    Hamels, Fanny; Malevé, Jasmina; Sonnet, Philippe; Kleja, Dan Berggren; Smolders, Erik

    2014-11-01

    Soil tests have been widely developed to predict trace metal uptake by plants. The prediction of metal toxicity, however, has rarely been tested. The present study was set up to compare 8 established soil tests for diagnosing phytotoxicity in contaminated soils. Nine soils contaminated with Zn or Cu by metal mining, smelting, or processing were collected. Uncontaminated reference soils with similar soil properties were sampled, and series of increasing contamination were created by mixing each with the corresponding soil. In addition, each reference soil was spiked with either ZnCl2 or CuCl2 at several concentrations. Total metal toxicity to barley seedling growth in the field-contaminated soils was up to 30 times lower than that in corresponding spiked soils. Total metal (aqua regia-soluble) toxicity thresholds of 50% effective concentrations (EC50) varied by factors up to 260 (Zn) or 6 (Cu) among soils. For Zn, variations in EC50 thresholds decreased as aqua regia > 0.43 M HNO3  > 0.05 M ethylenediamine tetraacetic acid (EDTA) > 1 M NH4 NO3  > cobaltihexamine > diffusive gradients in thin films (DGT) > 0.001 M CaCl2 , suggesting that the last extraction is the most robust phytotoxicity index for Zn. The EDTA extraction was the most robust for Cu-contaminated soils. The isotopically exchangeable fraction of the total soil metal in the field-contaminated soils markedly explained the lower toxicity compared with spiked soils. The isotope exchange method can be used to translate soil metal limits derived from soils spiked with metal salts to site-specific soil metal limits. © 2014 SETAC.

  20. Airborne soil particulates as vehicles for Salmonella contamination of tomatoes.

    PubMed

    Kumar, Govindaraj Dev; Williams, Robert C; Al Qublan, Hamzeh M; Sriranganathan, Nammalwar; Boyer, Renee R; Eifert, Joseph D

    2017-02-21

    The presence of dust is ubiquitous in the produce growing environment and its deposition on edible crops could occur. The potential of wind-distributed soil particulate to serve as a vehicle for S. Newport transfer to tomato blossoms and consequently, to fruits, was explored. Blossoms were challenged with previously autoclaved soil containing S. Newport (9.39log CFU/g) by brushing and airborne transfer. One hundred percent of blossoms brushed with S. Newport-contaminated soil tested positive for presence of the pathogen one week after contact (P<0.0001). Compressed air was used to simulate wind currents and direct soil particulates towards blossoms. Airborne soil particulates resulted in contamination of 29% of the blossoms with S. Newport one week after contact. Biophotonic imaging of blossoms post-contact with bioluminescent S. Newport-contaminated airborne soil particulates revealed transfer of the pathogen on petal, stamen and pedicel structures. Both fruits and calyxes that developed from blossoms contaminated with airborne soil particulates were positive for presence of S. Newport in both fruit (66.6%) and calyx (77.7%). Presence of S. Newport in surface-sterilized fruit and calyx tissue tested indicated internalization of the pathogen. These results show that airborne soil particulates could serve as a vehicle for Salmonella. Hence, Salmonella contaminated dust and soil particulate dispersion could contribute to pathogen contamination of fruit, indicating an omnipresent yet relatively unexplored contamination route. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Magnetic susceptibility properties of pesticide contaminated volcanic soil

    NASA Astrophysics Data System (ADS)

    Agustine, Eleonora; Fitriani, Dini; Safiuddin, La Ode; Tamuntuan, Gerald; Bijaksana, Satria

    2013-09-01

    Pesticides, unfortunately, are still widely used in many countries as way to eradicate agricultural pests. As they are being used continuously over a long period of time, they accumulate as residues in soils posing serious threats to the environment. In this study, we study the changes in magnetite-rich volcanic soils that were deliberately contaminated by pesticide. Such changes, in any, would be useful in the detection of pesticide residue in contaminated soils. Two different types of magnetically strong volcanic soil from the area near Lembang, West Java, Indonesia were used in this study where they were contaminated with varying concentrations of pesticide. The samples were then measured for magnetic susceptibility at two different frequencies. The measurements were then repeated after a period of three months. We found a reduction of magnetic susceptibility as well as a reduction in SP (superparamagnetic) grains proportion in contaminated soil. These might be caused by pesticide-induced magnetic dissolution as supported by SEM analyses. However the impact of pesticide concentration as well as exposure time on magnetic dissolution is still inconclusive.

  2. SURFACTANT SELECTION FOR ENHANCING EX SITU SOIL WASHING. (R825511C064)

    EPA Science Inventory

    Ex situ soil washing is commonly used for treating contaminated soils by separating the most contaminated fraction of the soil for disposal. Surfactant-enhanced soil washing is being considered with increasing frequency to actually achieve soil-contaminant separation. I...

  3. Soil properties controlling Zn speciation and fractionation in contaminated soils

    NASA Astrophysics Data System (ADS)

    Jacquat, Olivier; Voegelin, Andreas; Kretzschmar, Ruben

    2009-09-01

    We determined the speciation of Zn in 49 field soils differing widely in pH (4.1-7.7) and total Zn content (251-30,090 mg/kg) by using extended X-ray absorption fine structure (EXAFS) spectroscopy. All soils had been contaminated since several decades by inputs of aqueous Zn with runoff-water from galvanized power line towers. Pedogenic Zn species identified by EXAFS spectroscopy included Zn in hydroxy-interlayered minerals (Zn-HIM), Zn-rich phyllosilicates, Zn-layered double hydroxide (Zn-LDH), hydrozincite, and octahedrally and tetrahedrally coordinated sorbed or complexed Zn. Zn-HIM was only observed in (mostly acidic) soils containing less than 2000 mg/kg of Zn, reflecting the high affinity but limited sorption capacity of HIM. Zn-bearing precipitates, such as Zn-LDH and Zn-rich trioctahedral phyllosilicates, became more dominant with increasing pH and increasing total Zn content relative to available adsorption sites. Zn-LDH was the most abundant Zn-precipitate and was detected in soils with pH > 5.2. Zn-rich phyllosilicates were detected even at lower soil pH, but were generally less abundant than Zn-LDH. Hydrozincite was only identified in two calcareous soils with extremely high Zn contents. In addition to Zn-LDH, large amounts of Zn in highly contaminated soils were mainly accumulated as sorbed/complexed Zn in tetrahedral coordination. Soils grouped according to their Zn speciation inferred from EXAFS spectroscopy mainly differed with respect to soil pH and total Zn content. Clear differences were observed with respect to Zn fractionation by sequential extraction: From Zn-HIM containing soils, most of the total Zn was recovered in the exchangeable and the most recalcitrant fractions. In contrast, from soils containing the highest percentage of Zn-precipitates, Zn was mainly extracted in intermediate extraction steps. The results of this study demonstrate that soil pH and Zn contamination level relative to available adsorption sites are the most important

  4. BIOAVAILABILITY OF METALS IN CONTAMINATED SOIL AND DUST

    EPA Science Inventory

    Due to widespread metal contamination, it is necessary to characterize soils suspected of metal contamination and determine if the metal levels in these soils pose a hazard. Metal toxicity is often not directly related to the total concentration of metals present due to a numb...

  5. An evaluation of different soil washing solutions for remediating arsenic-contaminated soils.

    PubMed

    Wang, Yiwen; Ma, Fujun; Zhang, Qian; Peng, Changsheng; Wu, Bin; Li, Fasheng; Gu, Qingbao

    2017-04-01

    Soil washing is a promising way to remediate arsenic-contaminated soils. Most research has mostly focused on seeking efficient extractants for removing arsenic, but not concerned with any changes in soil properties when using this technique. In this study, the removal of arsenic from a heavily contaminated soil employing different washing solutions including H 3 PO 4 , NaOH and dithionite in EDTA was conducted. Subsequently, the changes in soil physicochemical properties and phytotoxicity of each washing technique were evaluated. After washing with 2 M H 3 PO 4 , 2 M NaOH or 0.1 M dithionite in 0.1 M EDTA, the soil samples' arsenic content met the clean-up levels stipulated in China's environmental regulations. H 3 PO 4 washing decreased soil pH, Ca, Mg, Al, Fe, and Mn concentrations but increased TN and TP contents. NaOH washing increased soil pH but decreased soil TOC, TN and TP contents. Dithionite in EDTA washing reduced soil TOC, Ca, Mg, Al, Fe, Mn and TP contents. A drastic color change was observed when the soil sample was washed with H 3 PO 4 or 0.1 M dithionite in 0.1 M EDTA. After adjusting the soil pH to neutral, wheat planted in the soil sample washed by NaOH evidenced the best growth of all three treated soil samples. These results will help with selecting the best washing solution when remediating arsenic-contaminated soils in future engineering applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Remediation of Cr(VI)-Contaminated Soil Using the Acidified Hydrazine Hydrate.

    PubMed

    Ma, Yameng; Li, Fangfang; Jiang, Yuling; Yang, Weihua; Lv, Lv; Xue, Haotian; Wang, Yangyang

    2016-09-01

    Acidified hydrazine hydrate was used to remediate Cr(VI)-contaminated soil. The content of water-soluble Cr(VI) in contaminated soil was 4977.53 mg/kg. The optimal initial pH of hydrazine hydrate solution, soil to solution ratio and molar ratio of Cr(VI) to hydrazine hydrate for remediation of Cr(VI)-contaminated soil were 5.0, 3:1 and 1:3, respectively. Over 99.50 % of water-soluble Cr(VI) in the contaminated soil was reduced at the optimal condition within 30 min. The remediated soil can keep stable within 4 months. Meanwhile the total phosphorus increased from 0.47 to 4.29 g/kg, indicating that using of acidified hydrazine hydrate is an effective method to remediate Cr(VI)-contaminated soil.

  7. Soil mixing of stratified contaminated sands.

    PubMed

    Al-Tabba, A; Ayotamuno, M J; Martin, R J

    2000-02-01

    Validation of soil mixing for the treatment of contaminated ground is needed in a wide range of site conditions to widen the application of the technology and to understand the mechanisms involved. Since very limited work has been carried out in heterogeneous ground conditions, this paper investigates the effectiveness of soil mixing in stratified sands using laboratory-scale augers. This enabled a low cost investigation of factors such as grout type and form, auger design, installation procedure, mixing mode, curing period, thickness of soil layers and natural moisture content on the unconfined compressive strength, leachability and leachate pH of the soil-grout mixes. The results showed that the auger design plays a very important part in the mixing process in heterogeneous sands. The variability of the properties measured in the stratified soils and the measurable variations caused by the various factors considered, highlighted the importance of duplicating appropriate in situ conditions, the usefulness of laboratory-scale modelling of in situ conditions and the importance of modelling soil and contaminant heterogeneities at the treatability study stage.

  8. Bioventing remediation and ecotoxicity evaluation of phenanthrene-contaminated soil.

    PubMed

    García Frutos, F Javier; Escolano, Olga; García, Susana; Babín, Mar; Fernández, M Dolores

    2010-11-15

    The objectives of soil remediation processes are usually based on threshold levels of soil contaminants. However, during remediation processes, changes in bioavailability and metabolite production can occur, making it necessary to incorporate an ecotoxicity assessment to estimate the risk to ecological receptors. The evolution of contaminants and soil ecotoxicity of artificially phenanthrene-contaminated soil (1000 mg/kg soil) during soil treatment through bioventing was studied in this work. Bioventing was performed in glass columns containing 5.5 kg of phenanthrene-contaminated soil and uncontaminated natural soil over a period of 7 months. Optimum conditions of mineralisation (humidity=60% WHC; C/N/P=100:20:1) were determined in a previous work. The evolution of oxygen consumption, carbon dioxide production, phenanthrene concentration and soil toxicity were studied on sacrificed columns at periods of 0, 3 and 7 months. Toxicity to soil and aquatic organisms was determined using a multispecies system in the soil columns (MS-3). In the optimal bioventing treatability test, we obtained a reduction rate in phenanthrene concentration higher that 93% after 7 months of treatment. The residual toxicity obtained at the end of the treatment was not attributed to the low phenanthrene concentration, but to the ammonia used to restore the optimal C/N ratio. Copyright © 2010 Elsevier B.V. All rights reserved.

  9. Urban community gardeners' knowledge and perceptions of soil contaminant risks.

    PubMed

    Kim, Brent F; Poulsen, Melissa N; Margulies, Jared D; Dix, Katie L; Palmer, Anne M; Nachman, Keeve E

    2014-01-01

    Although urban community gardening can offer health, social, environmental, and economic benefits, these benefits must be weighed against the potential health risks stemming from exposure to contaminants such as heavy metals and organic chemicals that may be present in urban soils. Individuals who garden at or eat food grown in contaminated urban garden sites may be at risk of exposure to such contaminants. Gardeners may be unaware of these risks and how to manage them. We used a mixed quantitative/qualitative research approach to characterize urban community gardeners' knowledge and perceptions of risks related to soil contaminant exposure. We conducted surveys with 70 gardeners from 15 community gardens in Baltimore, Maryland, and semi-structured interviews with 18 key informants knowledgeable about community gardening and soil contamination in Baltimore. We identified a range of factors, challenges, and needs related to Baltimore community gardeners' perceptions of risk related to soil contamination, including low levels of concern and inconsistent levels of knowledge about heavy metal and organic chemical contaminants, barriers to investigating a garden site's history and conducting soil tests, limited knowledge of best practices for reducing exposure, and a need for clear and concise information on how best to prevent and manage soil contamination. Key informants discussed various strategies for developing and disseminating educational materials to gardeners. For some challenges, such as barriers to conducting site history and soil tests, some informants recommended city-wide interventions that bypass the need for gardener knowledge altogether.

  10. Urban Community Gardeners' Knowledge and Perceptions of Soil Contaminant Risks

    PubMed Central

    Kim, Brent F.; Poulsen, Melissa N.; Margulies, Jared D.; Dix, Katie L.; Palmer, Anne M.; Nachman, Keeve E.

    2014-01-01

    Although urban community gardening can offer health, social, environmental, and economic benefits, these benefits must be weighed against the potential health risks stemming from exposure to contaminants such as heavy metals and organic chemicals that may be present in urban soils. Individuals who garden at or eat food grown in contaminated urban garden sites may be at risk of exposure to such contaminants. Gardeners may be unaware of these risks and how to manage them. We used a mixed quantitative/qualitative research approach to characterize urban community gardeners' knowledge and perceptions of risks related to soil contaminant exposure. We conducted surveys with 70 gardeners from 15 community gardens in Baltimore, Maryland, and semi-structured interviews with 18 key informants knowledgeable about community gardening and soil contamination in Baltimore. We identified a range of factors, challenges, and needs related to Baltimore community gardeners' perceptions of risk related to soil contamination, including low levels of concern and inconsistent levels of knowledge about heavy metal and organic chemical contaminants, barriers to investigating a garden site's history and conducting soil tests, limited knowledge of best practices for reducing exposure, and a need for clear and concise information on how best to prevent and manage soil contamination. Key informants discussed various strategies for developing and disseminating educational materials to gardeners. For some challenges, such as barriers to conducting site history and soil tests, some informants recommended city-wide interventions that bypass the need for gardener knowledge altogether. PMID:24516570

  11. Effect of soil texture on phytoremediation of arsenic-contaminated soils

    NASA Astrophysics Data System (ADS)

    Pallud, C. E.; Matzen, S. L.; Olson, A.

    2015-12-01

    Soil arsenic (As) contamination is a global problem, resulting in part from anthropogenic activities, including the use of arsenical pesticides and treated wood, mining, and irrigated agriculture. Phytoextraction using the hyperaccumulating fern Pteris vittata is a promising new technology to remediate soils with shallow arsenic contamination with minimal site disturbance. However, many challenges still lie ahead for a global application of phytoremediation. For example, remediation times using P. vittata are on the order of decades. In addition, most research on As phytoextraction with P. vittata has examined As removal from sandy soils, where As is more available, with little research focusing on As removal from clayey soils, where As is less available. The objective of this study is to determine the effects of soil texture and soil fertilization on As extraction by P. vittata, to optimize remediation efficiency and decrease remediation time under complex field conditions. A field study was established 2.5 years ago in an abandoned railroad grade contaminated with As (average 85.5 mg kg-1) with texture varying from sandy loam to silty clay loam. Organic N, inorganic N, organic P, inorganic P, and compost were applied to separate sub-plots; control ferns were grown in untreated soil. In a parallel greenhouse experiment, ferns were grown in sandy loam soil extracted from the field (180 mg As kg-1), with similar treatments as those used at the field site, plus a high phosphate treatment and treatments with arbuscular mycorrhizal fungi. In the field study, fern mortality was 24% higher in clayey soil than in sandy soil due to waterlogging, while As was primarily associated with sandy soil. Results from the sandy loam soil indicate that soil treatments did not significantly increase As phytoextraction, which was lower in phosphate-treated ferns than in control ferns, both in the field and greenhouse study. Under greenhouse conditions, ferns treated with organic N were

  12. Electrokinetic In Situ Treatment of Metal-Contaminated Soil

    NASA Technical Reports Server (NTRS)

    Quinn, Jacqueline; Clausen, Christian A., III; Geiger, Cherie; Reinhart, Debra

    2004-01-01

    An electrokinetic technique has been developed as a means of in situ remediation of soils, sludges, and sediments that are contaminated with heavy metals. Examples of common metal contaminants that can be removed by this technique include cadmium, chromium, zinc, lead, mercury, and radionuclides. Some organic contaminants can also be removed by this technique. In the electrokinetic technique, a low-intensity direct current is applied between electrodes that have been implanted in the ground on each side of a contaminated soil mass. The electric current causes electro-osmosis and migration of ions, thereby moving aqueous-phase subsurface contaminants from one electrode to the other. The half reaction at the anode yields H+, thereby generating an acid front that travels from the anode toward the cathode. As this acid front passes through a given location, the local increase in acidity increases the solubility of cations that were previously adsorbed on soil particles. Ions are transported towards one electrode or the other which one depending on their respective electric charges. Upon arrival at the electrodes, the ionic contaminants can be allowed to become deposited on the electrodes or can be extracted to a recovery system. Surfactants and other reagents can be introduced at the electrodes to enhance rates of removal of contaminants. Placements of electrodes and concentrations and rates of pumping of reagents can be adjusted to maximize efficiency. The basic concept of electrokinetic treatment of soil is not new. What is new here are some of the details of application and the utilization of this technique as an alternative to other techniques (e.g., flushing or bioremediation) that are not suitable for treating soils of low hydraulic conductivity. Another novel aspect is the use of this technique as a less expensive alternative to excavation: The cost advantage over excavation is especially large in settings in which contaminated soil lies near and/or under

  13. Natural attenuation is enhanced in previously contaminated and coniferous forest soils.

    PubMed

    Kauppi, Sari; Romantschuk, Martin; Strömmer, Rauni; Sinkkonen, Aki

    2012-01-01

    Prevalence of organic pollutants or their natural analogs in soil is often assumed to lead to adaptation in the bacterial community, which results in enhanced bioremediation if the soil is later contaminated. In this study, the effects of soil type and contamination history on diesel oil degradation and bacterial adaptation were studied. Mesocosms of mineral and organic forest soil (humus) were artificially treated with diesel oil, and oil hydrocarbon concentrations (GC-FID), bacterial community composition (denaturing gradient gel electrophoresis, DGGE), and oil hydrocarbon degraders (DGGE + sequencing of 16S rRNA genes) were monitored for 20 weeks at 16°C. Degradation was advanced in previously contaminated soils as compared with pristine soils and in coniferous organic forest soil as compared with mineral soil. Contamination affected bacterial community composition especially in the pristine mineral soil, where diesel addition increased the number of strong bands in the DGGE gel. Sequencing of cloned 16S rRNA gene fragments and DGGE bands showed that potential oil-degrading bacteria were found in mineral and organic soils and in both pristine and previously contaminated mesocosms. Fast oil degradation was not associated with the presence of any particular bacterial strain in soil. We demonstrate at the mesocosm scale that previously contaminated and coniferous organic soils are superior environments for fast oil degradation as compared with pristine and mineral soil environments. These results may be utilized in preventing soil pollution and planning soil remediation.

  14. Changes in the structure and function of soil ecosystems in soils contaminated with heavy metals

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kuperman, R.; Parmelee, R.; Carreiro, M.

    1995-09-01

    The structure and function of soil communities in an area with a wide range of concentrations of heavy metals was studied in portions of the U.S. Army`s Aberdeen Proving Ground, Maryland. The study included survey of soil macro- and microinvertebrate communities, soil microorganisms, enzyme activities and the rates of nutrient dynamics in soil. Soil macroinvertebrate communities showed significant reductions in the adundance of several taxonomic and functional groups in contaminated areas. The total numbers of nematodes and numbers of fungivore, bacterivore and omnivore-predator nematodes were lower in the more contaminated areas. The numbers of active bacteria and fungi were lowermore » in areas of soil contamination. Significant reduction in the activities of all enzymes closely paralleled the increase in heavy metal concentrations. Ten-to-fifty fold reductions in enzyme activities were observed as heavy metal concentrations increased. These results suggest that soil contamination with heavy metals may have detrimental effects on soil biota and the rates of organic matter degradation and subsequent release of nutrients to aboveground communities in the area.« less

  15. Changes in the structure and function of soil ecosystems in soils contaminated with heavy metals

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kuperman, R.; Parmelee, R.; Carreiro, M.

    1995-06-01

    The structure and function of soil communities in an area with a wide range of concentrations of heavy metals was studied in portions of the U.S. Army`s Aberdeen Proving Ground, Maryland. The study included survey of soil macro- and microinvertebrate communities, soil microorganisms, enzyme activities and the rates of nutrient dynamics in soil. Soil macroinvertebrate communities showed significant reductions in the abundance of several taxonomic and functional groups in contaminated areas. The total numbers of nematodes and numbers of fungivore, bacterivore and omnivore-predator nematodes were lower in the more contaminated areas. The numbers of active bacteria and fungi were lowermore » in areas of soil contamination. Significant reduction in the activities of all enzymes closely paralleled the increase in heavy metal concentrations. Ten-to-fifty fold reductions in enzyme activities were observed as heavy metal concentrations increased. These results suggest that soil contamination with heavy metals may have detrimental effects on soil biota and the rates of organic matter degradation and subsequent release of nutrients to aboveground communities in the area.« less

  16. Does Diffusion Sequester Heavy Metals in Old Contamination Soils?

    NASA Astrophysics Data System (ADS)

    Ma, J.; Jennings, A. A.

    2002-12-01

    Old soil contamination refers to soil contamination that has aged over a long period of time. For example, at some brownfields, the soil heavy metal contamination can be one hundred or more years old. When contamination is young, the heavy metals are bound relatively weakly to the soil. However, the speciation and/or mechanisms of association evolve with aging into much more stable forms. It also appears that the metals migrate deeper into the bulk soil matrix where they are less available to participate in surface-related phenomena. Previous research showed elevated heavy metal extraction result after the soil was pulverized, with all other experiment conditions remaining unchanged. This indicates the presence of sequestered heavy metal contamination within the large soil particles (aggregate). The mechanisms of sequestering are uncertain, but diffusion appears to be a major factor. There are two possible pathways of diffusion that can account for heavy metal sequestering: solid-state diffusion through the bulk aggregate or liquid-phase diffusion through micro-pores within the aggregate structure. The second diffusion mechanism can be coupled with sorption (or other surface-related phenomena) on the pore walls. The remediation of sequestered heavy metals is also impacted by diffusion. Grinding a soil significantly reduces its average particle size. This exposes more of its internal bulk volume to extraction and results in much shorter diffusion pathway for the sequestered heavy metals to be released. Evidence has illustrated that this both improves remediation efficiency and provides a method by which the degree of sequestering can be quantified. This paper will present the results of ongoing research that is developing methods to identify the mechanisms of, quantify the magnitude of and determine the relative importance of (i.e. risk analysis) heavy metals sequestered in old contamination soils.

  17. Some aspects of remediation of contaminated soils

    NASA Astrophysics Data System (ADS)

    Bech, Jaume; Korobova, Elena; Abreu, Manuela; Bini, Claudio; Chon, Hyo-Taek; Pérez-Sirvent, Carmen; Roca, Núria

    2014-05-01

    Soils are essential components of the environment, a limited precious and fragile resource, the quality of which should be preserved. The concentration, chemical form and distribution of potential harmful elements in soils depends on parent rocks, weathering, soil type and soil use. However, their concentration can be altered by mismanagement of industrial and mining activities, energy generation, traffic increase, overuse of agrochemicals, sewage sludge and waste disposal, causing contamination, environmental problems and health concerns. Heavy metals, some metalloids and radionuclides are persistent in the environment. This persistence hampers the cost/efficiency of remediation technologies. The choice of the most appropriate soil remediation techniques depends of many factors and essentially of the specific site. This contribution aims to offer an overview of the main remediation methods in contaminated soils. There are two main groups of technologies: the first group dealing with containment and confinement, minimizing their toxicity, mobility and bioavailability. Containment measures include covering, sealing, encapsulation and immobilization and stabilization. The second group, remediation with decontamination, is based on the remotion, clean up and/or destruction of contaminants. This group includes mechanical procedures, physical separations, chemical technologies such as soil washing with leaching or precipitation of harmful elements, soil flushing, thermal treatments and electrokinetic technologies. There are also two approaches of biological nature: bioremediation and phytoremediation. Case studies from Chile, Ecuador, Italy, Korea, Peru, Portugal, Russia and Spain, will be discussed in accordance with the time available.

  18. Community-level physiological profiles of microorganisms inhabiting soil contaminated with heavy metals

    NASA Astrophysics Data System (ADS)

    Kuźniar, Agnieszka; Banach, Artur; Stępniewska, Zofia; Frąc, Magdalena; Oszust, Karolina; Gryta, Agata; Kłos, Marta; Wolińska, Agnieszka

    2018-01-01

    The aim of the study was to assess the differences in the bacterial community physiological profiles in soils contaminated with heavy metals versus soils without metal contaminations. The study's contaminated soil originated from the surrounding area of the Szopienice non-ferrous metal smelter (Silesia Region, Poland). The control was soil unexposed to heavy metals. Metal concentration was appraised by flame atomic absorption spectrometry, whereas the the community-level physiological profile was determined with the Biolog EcoPlatesTM system. The soil microbiological activity in both sites was also assessed via dehydrogenase activity. The mean concentrations of metals (Cd and Zn) in contaminated soil samples were in a range from 147.27 to 12265.42 mg kg-1, and the heavy metal contamination brought about a situation where dehydrogenase activity inhibition was observed mostly in the soil surface layers. Our results demonstrated that there is diversity in the physiological profiles of microorganisms inhabiting contaminated and colntrol soils; therefore, for assessment purposes, these were treated as two clusters. Cluster I included colntrol soil samples in which microbial communities utilised most of the available substrates. Cluster II incorporated contaminated soil samples in which a smaller number of the tested substrates was utilised by the contained microorganisms. The physiological profiles of micro-organisms inhabiting the contaminated and the colntrol soils are distinctly different.

  19. Heavy-metal contamination of soils in Saxony/Germany by foundry fumes and low-cost rapid analyses of contaminated soils by XRF

    NASA Astrophysics Data System (ADS)

    Mucke, D.

    2012-04-01

    Heavy-metal contamination of soils in Saxony/Germany by foundry fumes and low-cost rapid analysis of contaminated soils by XRF Dieter Mucke, Rolf Kumann, Sebastian Baldauf GEOMONTAN Gesellschaft für Geologie und Bergbau mbH&Co.KG, Muldentalstrasse 56, 09603 Rothenfurth, Saxony/Germany For hundreds of years in the Ore Mountains between Bohemia and Saxony silver and other ores are produced and smelted. Sulphide- and sulpharsenide-ores needed to be roasted first. In doing so the sulphide sulphur was oxidised under formation of sulphur dioxide SO2 and arsenide conversed into elemental arsenic and arsenide trioxide As2O3 respectively. Also the metals lead, cadmium and zinc are components of hut smokes, in the field of nickel foundries also nickel. The contents of soils basically reflect the geogenic conditions, which are caused by decomposition- and relocation-effects of the mineralisations, in the area of foundries also with influences by with the hut smokes anthropogenic mobilised elements. The Saxonian Agency for Environment and Geology drafted in 1992 a Soil Investigation Program with the aim of investigation of the contamination of Saxonian soils with arsenic and toxic heavy metals. In order of this Agency GEOMONTAN investigated 1164 measuring points in the grid 4 * 4 km.soil profiles and extracted soil samples for analysis. In the result of the laboratory examinations the Agency edited the "Soil atlas of the Free State of Saxony". 27 elements, pH and PAK are shown in detailed maps and allow in whole Saxony the first assessment of the contamination of soils with arsenic and toxic heavy metals. Each of the investigated soil profiles represent an area of 16 km2. Already by the different use of the districts (agricultural, industrial, urban) restricts representative values. GEOMONTAN in the meantime used at the exploration of a copper deposit in Brandenburg/Germany with approx. 50,000 single tests at drill cores a very fast low-cost method: the X Ray fluorescence

  20. Treatment of NORM contaminated soil from the oilfields.

    PubMed

    Abdellah, W M; Al-Masri, M S

    2014-03-01

    Uncontrolled disposal of oilfield produced water in the surrounding environment could lead to soil contamination by naturally occurring radioactive materials (NORM). Large volumes of soil become highly contaminated with radium isotopes ((226)Ra and (228)Ra). In the present work, laboratory experiments have been conducted to reduce the activity concentration of (226)Ra in soil. Two techniques were used, namely mechanical separation and chemical treatment. Screening of contaminated soil using vibratory sieve shaker was performed to evaluate the feasibility of particle size separation. The fractions obtained were ranged from less than 38 μm to higher than 300 μm. The results show that (226)Ra activity concentrations vary widely from fraction to fraction. On the other hand, leaching of (226)Ra from soil by aqueous solutions (distilled water, mineral acids, alkaline medias and selective solvents) has been performed. In most cases, relatively low concentrations of radium were transferred to solutions, which indicates that only small portions of radium are present on the surface of soil particles (around 4.6%), while most radium located within soil particles; only concentrated nitric acid was most effective where 50% of (226)Ra was removed to aqueous phase. However, mechanical method was found to be easy and effective, taking into account safety procedures to be followed during the implementation of the blending and homogenization. Chemical extraction methods were found to be less effective. The results obtained in this study can be utilized to approach the final option for disposal of NORM contaminated soil in the oilfields. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Estimated association between dwelling soil contamination and internal radiation contamination levels after the 2011 Fukushima Daiichi nuclear accident in Japan

    PubMed Central

    Tsubokura, Masaharu; Nomura, Shuhei; Sakaihara, Kikugoro; Kato, Shigeaki; Leppold, Claire; Furutani, Tomoyuki; Morita, Tomohiro; Oikawa, Tomoyoshi; Kanazawa, Yukio

    2016-01-01

    Objectives Measurement of soil contamination levels has been considered a feasible method for dose estimation of internal radiation exposure following the Chernobyl disaster by means of aggregate transfer factors; however, it is still unclear whether the estimation of internal contamination based on soil contamination levels is universally valid or incident specific. Methods To address this issue, we evaluated relationships between in vivo and soil cesium-137 (Cs-137) contamination using data on internal contamination levels among Minamisoma (10–40 km north from the Fukushima Daiichi nuclear power plant), Fukushima residents 2–3 years following the disaster, and constructed three models for statistical analysis based on continuous and categorical (equal intervals and quantiles) soil contamination levels. Results A total of 7987 people with a mean age of 55.4 years underwent screening of in vivo Cs-137 whole-body counting. A statistically significant association was noted between internal and continuous Cs-137 soil contamination levels (model 1, p value <0.001), although the association was slight (relative risk (RR): 1.03 per 10 kBq/m2 increase in soil contamination). Analysis of categorical soil contamination levels showed statistical (but not clinical) significance only in relatively higher soil contamination levels (model 2: Cs-137 levels above 100 kBq/m2 compared to those <25 kBq/m2, RR=1.75, p value <0.01; model 3: levels above 63 kBq/m2 compared to those <11 kBq/m2, RR=1.45, p value <0.05). Conclusions Low levels of internal and soil contamination were not associated, and only loose/small associations were observed in areas with slightly higher levels of soil contamination in Fukushima, representing a clear difference from the strong associations found in post-disaster Chernobyl. These results indicate that soil contamination levels generally do not contribute to the internal contamination of residents in Fukushima; thus, individual

  2. Quicklime-induced changes of soil properties: Implications for enhanced remediation of volatile chlorinated hydrocarbon contaminated soils via mechanical soil aeration.

    PubMed

    Ma, Yan; Dong, Binbin; He, Xiaosong; Shi, Yi; Xu, Mingyue; He, Xuwen; Du, Xiaoming; Li, Fasheng

    2017-04-01

    Mechanical soil aeration is used for soil remediation at sites contaminated by volatile organic compounds. However, the effectiveness of the method is limited by low soil temperature, high soil moisture, and high soil viscosity. Combined with mechanical soil aeration, quicklime has a practical application value related to reinforcement remediation and to its action in the remediation of soil contaminated with volatile organic compounds. In this study, the target pollutant was trichloroethylene, which is a volatile chlorinated hydrocarbon pollutant commonly found in contaminated soils. A restoration experiment was carried out, using a set of mechanical soil-aeration simulation tests, by adding quicklime (mass ratios of 3, 10, and 20%) to the contaminated soil. The results clearly indicate that quicklime changed the physical properties of the soil, which affected the environmental behaviour of trichloroethylene in the soil. The addition of CaO increased soil temperature and reduced soil moisture to improve the mass transfer of trichloroethylene. In addition, it improved the macroporous cumulative pore volume and average pore size, which increased soil permeability. As soil pH increased, the clay mineral content in the soils decreased, the cation exchange capacity and the redox potential decreased, and the removal of trichloroethylene from the soil was enhanced to a certain extent. After the addition of quicklime, the functional group COO of soil organic matter could interact with calcium ions, which increased soil polarity and promoted the removal of trichloroethylene. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Microscale Investigations of Soil Heterogeneity: Impacts on Zinc Retention and Uptake in Zinc-Contaminated Soils

    DOE PAGES

    Rosenfeld, Carla E.; Chaney, Rufus L.; Tappero, Ryan V.; ...

    2017-03-17

    Here, metal contaminants in soils can persist for millennia, causing lasting negative impacts on local ecosystems. Long-term contaminant bioavailability is related to soil pH and to the strength and stability of solid-phase associations. We combined physical density separation with synchrotron-based microspectroscopy to reduce solid-phase complexity and to study Zn speciation in field-contaminated soils. We also investigated Zn uptake in two Zn-hyperaccumulating ecotypes of Noccaea caerulescens (Ganges and Prayon). Soils were either moderately contaminated (500–800 mg Zn kg –1 via contaminated biosolids application) or grossly enriched (26,000 mg Zn kg –1 via geogenic enrichment). Soils were separated using sodium polytungstate intomore » three fractions: light fraction (LF) (<1.6 g cm –3), medium fraction (MF) (1.6–2.8 g cm –3), and heavy fraction (HF) (>2.8 g cm –3). Approximately 45% of the total Zn was associated with MF in biosolids-contaminated soils. From these data, we infer redistribution to the MF after biosolids application because Zn in biosolids is principally associated with HF and LF. Our results suggest that increasing proportions of HF-associated Zn in soils may be related to greater relative Zn removal by Zn hyperaccumulating plants. Using density fractions enabled assessment of Zn speciation on a microscale despite incomplete fractionation. Analyzing both density fractions and whole soils revealed certain phases (e.g., ZnS, Zn coprecipitated with Fe oxides) that were not obvious in all analyses, indicating multiple views of the same soils enable a more complete understanding of Zn speciation.« less

  4. Electromigration of Contaminated Soil by Electro-Bioremediation Technique

    NASA Astrophysics Data System (ADS)

    Azhar, A. T. S.; Nabila, A. T. A.; Nurshuhaila, M. S.; Shaylinda, M. Z. N.; Azim, M. A. M.

    2016-07-01

    Soil contamination with heavy metals poses major environmental and human health problems. This problem needs an efficient method and affordable technological solution such as electro-bioremediation technique. The electro-bioremediation technique used in this study is the combination of bacteria and electrokinetic process. The aim of this study is to investigate the effectiveness of Pseudomonas putida bacteria as a biodegradation agent to remediate contaminated soil. 5 kg of kaolin soil was spiked with 5 g of zinc oxide. During this process, the anode reservoir was filled with Pseudomonas putida while the cathode was filled with distilled water for 5 days at 50 V of electrical gradient. The X-Ray Fluorescent (XRF) test indicated that there was a significant reduction of zinc concentration for the soil near the anode with 89% percentage removal. The bacteria count is high near the anode which is 1.3x107 cfu/gww whereas the bacteria count at the middle and near the cathode was 5.0x106 cfu/gww and 8.0x106 cfu/gww respectively. The migration of ions to the opposite charge of electrodes during the electrokinetic process resulted from the reduction of zinc. The results obtained proved that the electro-bioremediation reduced the level of contaminants in the soil sample. Thus, the electro-bioremediation technique has the potential to be used in the treatment of contaminated soil.

  5. Remediation techniques for heavy metal-contaminated soils: Principles and applicability.

    PubMed

    Liu, Lianwen; Li, Wei; Song, Weiping; Guo, Mingxin

    2018-08-15

    Globally there are over 20millionha of land contaminated by the heavy metal(loid)s As, Cd, Cr, Hg, Pb, Co, Cu, Ni, Zn, and Se, with the present soil concentrations higher than the geo-baseline or regulatory levels. In-situ and ex-situ remediation techniques have been developed to rectify the heavy metal-contaminated sites, including surface capping, encapsulation, landfilling, soil flushing, soil washing, electrokinetic extraction, stabilization, solidification, vitrification, phytoremediation, and bioremediation. These remediation techniques employ containment, extraction/removal, and immobilization mechanisms to reduce the contamination effects through physical, chemical, biological, electrical, and thermal remedy processes. These techniques demonstrate specific advantages, disadvantages, and applicability. In general, in-situ soil remediation is more cost-effective than ex-situ treatment, and contaminant removal/extraction is more favorable than immobilization and containment. Among the available soil remediation techniques, electrokinetic extraction, chemical stabilization, and phytoremediation are at the development stage, while the others have been practiced at full, field scales. Comprehensive assessment indicates that chemical stabilization serves as a temporary soil remediation technique, phytoremediation needs improvement in efficiency, surface capping and landfilling are applicable to small, serious-contamination sites, while solidification and vitrification are the last remediation option. The cost and duration of soil remediation are technique-dependent and site-specific, up to $500ton -1 soil (or $1500m -3 soil or $100m -2 land) and 15years. Treatability studies are crucial to selecting feasible techniques for a soil remediation project, with considerations of the type and degree of contamination, remediation goals, site characteristics, cost effectiveness, implementation time, and public acceptability. Copyright © 2018 Elsevier B.V. All rights

  6. Vertical characterization of soil contamination using multi-way modeling--a case study.

    PubMed

    Singh, Kunwar P; Malik, Amrita; Basant, Ankita; Ojha, Priyanka

    2008-11-01

    This study describes application of chemometric multi-way modeling approach to analyze the dataset pertaining to soils of industrial area with a view to assess the soil/sub-soil contamination, accumulation pathways and mobility of contaminants in the soil profiles. The three-way (sampling depths, chemical variables, sampling sites) dataset on heavy metals in soil samples collected from three different sites in an industrial area, up to a depth of 60 m each was analyzed using three-way Tucker3 model validated for stability and goodness of fit. A two component Tucker3 model, explaining 66.6% of data variance, allowed interpretation of the data information in all the three modes. The interpretation of core elements revealing interactions among the components of different modes (depth, variables, sites) allowed inferring more realistic information about the contamination pattern of soils both along the horizontal and vertical coordinates, contamination pathways, and mobility of contaminants through soil profiles, as compared to the traditional data analysis techniques. It concluded that soils at site-1 and site-2 are relatively more contaminated with heavy metals of both the natural as well as anthropogenic origins, as compared to the soil of site-3. Moreover, the accumulation pathways of metals for upper shallow layers and deeper layers of soils in the area were differentiated. The information generated would be helpful in developing strategies for remediation of the contaminated soils for reducing the subsequent risk of ground-water contamination in the study region.

  7. Surfactant-Enhanced Desorption and Biodegradation of Polycyclic Aromatic Hydrocarbons in Contaminated Soil

    PubMed Central

    Zhu, Hongbo; Aitken, Michael D.

    2010-01-01

    We evaluated two nonionic surfactants, one hydrophobic (Brij 30) and one hydrophilic (C12E8), for their ability to enhance the biodegradation of polycyclic aromatic hydrocarbons (PAHs) in contaminated soil after it had been treated in an aerobic bioreactor. The effects of each surfactant were evaluated at doses corresponding to equilibrium aqueous-phase concentrations well above the surfactant’s critical micelle concentration (CMC), slightly above the CMC, and below the CMC. The concentrations of all 3- and 4-ring PAHs were significantly lower in the soil amended with Brij 30 at the two lower doses compared to controls, whereas removal of only the 3-ring PAHs was significantly enhanced at the highest Brij 30 dose. In contrast, C12E8 did not enhance PAH removal at any dose. In the absence of surfactant, <5% of any PAH desorbed from the soil over an 18-d period. Brij 30 addition at the lowest dose significantly increased the desorption of most PAHs, whereas the addition of C12E8 at the lowest dose actually decreased the desorption of all PAHs. These findings suggest that the effects of the two surfactants on PAH biodegradation could be explained by their effects on PAH bioavailability. Overall, this study demonstrates that the properties of the surfactant and its dose relative to the corresponding aqueous-phase concentration are important factors in designing systems for surfactant-enhanced bioremediation of PAH-contaminated soils in which PAH bioavailability is limited. PMID:20586488

  8. Complex conductivity of oil-contaminated clayey soils

    NASA Astrophysics Data System (ADS)

    Deng, Yaping; Shi, Xiaoqing; Revil, André; Wu, Jichun; Ghorbani, A.

    2018-06-01

    Spectral induced polarization (SIP) is considered as a promising tool in environmental investigations. However, few works have done regarding the electrical signature of oil contamination of clayey soils upon induced polarization. Laboratory column experiments plus one sandbox experiment are conducted in this study to investigate the performances of the SIP method in oil-contaminated soils. First, a total of 12 soils are investigated to reveal the influences of water and soil properties on the saturation dependence of the complex conductivity below 100 Hz. Results show that the magnitude of the complex conductivity consistently decreases with decreasing water saturation for all soils samples. The saturation n and quadrature conductivity p exponents tend to increase slightly with increasing water salinity when using a linear conductivity model. The saturation exponent increases marginally with the cation exchange capacity (CEC) and the specific surface area (Ssp) while the quadrature conductivity exponent exhibits a relatively stronger dependence on both CEC and Ssp. For the low CEC soil samples (normally ≤10 meq/100 g), the quadrature conductivity exponent p correlates well with the saturation exponent n using the relationship p = n-1. SIP method is further applied in a sandbox experiment to estimate the saturation distribution and total volume of the oil. Results demonstrate that the SIP method has a great potential for mapping the organic contaminant plume and quantifying the oil volume.

  9. Enrichment of arbuscular mycorrhizal fungi in a contaminated soil after rehabilitation.

    PubMed

    Lopes Leal, Patrícia; Varón-López, Maryeimy; Gonçalves de Oliveira Prado, Isabelle; Valentim Dos Santos, Jessé; Fonsêca Sousa Soares, Cláudio Roberto; Siqueira, José Oswaldo; de Souza Moreira, Fatima Maria

    Spore counts, species composition and richness of arbuscular mycorrhizal fungi, and soil glomalin contents were evaluated in a soil contaminated with Zn, Cu, Cd and Pb after rehabilitation by partial replacement of the contaminated soil with non-contaminated soil, and by Eucalyptus camaldulensis planting with and without Brachiaria decumbens sowing. These rehabilitation procedures were compared with soils from contaminated non-rehabilitated area and non-contaminated adjacent soils. Arbuscular mycorrhizal fungi communities attributes were assessed by direct field sampling, trap culture technique, and by glomalin contents estimate. Arbuscular mycorrhizal fungi was markedly favored by rehabilitation, and a total of 15 arbuscular mycorrhizal fungi morphotypes were detected in the studied area. Species from the Glomus and Acaulospora genera were the most common mycorrhizal fungi. Number of spores was increased by as much as 300-fold, and species richness almost doubled in areas rehabilitated by planting Eucalyptus in rows and sowing B. decumbens in inter-rows. Contents of heavy metals in the soil were negatively correlated with both species richness and glomalin contents. Introduction of B. decumbens together with Eucalyptus causes enrichment of arbuscular mycorrhizal fungi species and a more balanced community of arbuscular mycorrhizal fungi spores in contaminated soil. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  10. Contribution of microorganisms to non-extractable residue formation from biodegradable organic contaminants in soil

    NASA Astrophysics Data System (ADS)

    Nowak, K. M.; Girardi, C.; Miltner, A.; Schäffer, A.; Kästner, M.

    2012-04-01

    Biodegradation of organic contaminants in soil is actually understood as their transformation into various primary metabolites, microbial biomass, mineralisation products and non-extractable residues (NER). NER are generally considered to be composed of parent compounds or primary metabolites with hazardous potential. Up to date, however, their chemical composition remains still unclear. Studies on NER formation are limited to quantitative analyses in soils or to simple humic acids-contaminant systems. However, in the case of biodegradable organic compounds, NER may also contain microbial biomass components, e.g. fatty acids (FA) and amino acids (AA). After cell death, these biomolecules are incorporated into soil organic matter (SOM) and stabilised, ultimately forming biogenic residues which are not any more extractable. We investigated the incorporation of the 13C-label into FA and AA and their fate during biodegradation experiments in soil with isotope-labelled 2,4-dichlorophenoxyacetic acid (13C6-2,4-D) and ibuprofen (13C6-ibu) as model organic contaminants. Our study proved for the first time that nearly all NER formed from 13C6-2,4-D and 13C6-ibu in soil derived from harmless microbial biomass components stabilised in SOM. 13C-FA and 13C-AA contents in the living microbial biomass fraction decreased over time and these components were continuously incorporated into the non-living SOM pool in biotic experiments with 13C6-2,4-D and 13C6-ibu. The 13C-AA in the non-living SOM were surprisingly stable from day 32 (13C6-2,4-D) and 58 (13C6-ibu) until the end of incubation. We also studied the transformation of 13C6-2,4-D and 13C6-ibu into NER in the abiotic soil experiments. In these experiments, the total NER contents were much lower than in the corresponding biotic experiments. The absence of labelled biomolecules in the NER fraction in abiotic soils demonstrated that they consist of the potentially hazardous parent compounds and / or their metabolites. Biogenic

  11. Electrokinetic electrode system for extraction of soil contaminants from unsaturated soils

    DOEpatents

    Lindgren, Eric R.; Mattson, Earl D.

    1995-01-01

    There is presented an electrokinetic electrode assembly for use in extraction of soil contaminants from unsaturated soil in situ. The assembly includes a housing for retaining a liquid comprising an electrolyte solution, pure water, and soil water, the housing being in part of porous material capable of holding a vacuum. An electrode is mounted in the housing. The housing is provided with a vacuum orifice for effecting a vacuum within the housing selectively to control flow of soil water through the housing into the chamber and to control outflow of the liquid from the chamber. The assembly further includes conduit means for removing the liquid from the housing and returning the electrolyte solution to the housing, and a conduit for admitting pure water to the housing. There is further presented an electrode system and method for extraction of soil contaminants, the system and method utilizing at least two electrode assemblies as described above.

  12. Electrokinetic electrode system for extraction of soil contaminants from unsaturated soils

    DOEpatents

    Lindgren, E.R.; Mattson, E.D.

    1995-07-25

    An electrokinetic electrode assembly is described for use in extraction of soil contaminants from unsaturated soil in situ. The assembly includes a housing for retaining a liquid comprising an electrolyte solution, pure water, and soil water, the housing being in part of porous material capable of holding a vacuum. An electrode is mounted in the housing. The housing is provided with a vacuum orifice for effecting a vacuum within the housing selectively to control flow of soil water through the housing into the chamber and to control outflow of the liquid from the chamber. The assembly further includes conduit means for removing the liquid from the housing and returning the electrolyte solution to the housing, and a conduit for admitting pure water to the housing. An electrode system and method are also revealed for extraction of soil contaminants. The system and method utilize at least two electrode assemblies as described above. 5 figs.

  13. Biological Activity Assessment in Mexican Tropical Soils with Different Hydrocarbon Contamination Histories.

    PubMed

    Riveroll-Larios, Jessica; Escalante-Espinosa, Erika; Fócil-Monterrubio, Reyna L; Díaz-Ramírez, Ildefonso J

    The use of soil health indicators linked to microbial activities, such as key enzymes and respirometric profiles, helps assess the natural attenuation potential of soils contaminated with hydrocarbons. In this study, the intrinsic physicochemical characteristics, biological activity and biodegradation potential were recorded for two soils with different contamination histories (>5 years and <1 months). The enzymatic activity (lipase and dehydrogenase) as well as microbiological and mineralisation profiles were measured in contaminated soil samples. Soil suspensions were tested as microbial inocula in biodegradation potential assays using contaminated perlite as an inert support. The basal respiratory rate of the recently contaminated soil was 15-38 mg C-CO 2  kg -1 h -1 , while the weathered soil presented a greater basal mineralisation capacity of 55-70 mg C-CO 2 kg -1 h -1 . The basal levels of lipase and dehydrogenase were significantly greater than those recorded in non-contaminated soils (551 ± 21 μg pNP g -1 ). Regarding the biodegradation potential assessment, the lipase (1000-3000 μg pNP g -1 of perlite) and dehydrogenase (~3000 μg INF g -1 of perlite) activities in the inoculum of the recently contaminated soil were greater than those recorded in the inoculum of the weathered soil. This was correlated with a high mineralisation rate (~30 mg C-CO 2 kg -1 h -1 ) in the recently contaminated soil and a reduction in hydrocarbon concentration (~30 %). The combination of an inert support and enzymatic and respirometric analyses made it possible to detect the different biodegradation capacities of the studied inocula and the natural attenuation potential of a recently contaminated soil at high hydrocarbon concentrations.

  14. Identifying root exudates in field contaminated soil systems

    NASA Astrophysics Data System (ADS)

    Rosenfeld, C.; Martinez, C. E.

    2012-12-01

    Carbon (C) compounds exuded from plant roots comprise a significant and reactive fraction of belowground C pools. These exudates substantially alter the soil directly surrounding plant roots and play a vital role in the global C cycle, soil ecology, and ecosystem mobility of both nutrients and contaminants. In soils, the solubility and bioavailability of metals such as iron, zinc, and cadmium are intricately linked to the quantity and chemical characteristics of the C compounds allocated to the soil by plants. Cadmium (Cd), a toxic heavy metal, forms stronger bonds with reduced S- and N-containing compounds than with carboxylic acids, which may influence exudate composition in hyperaccumulator and tolerant plants grown in Cd contaminated soils. We hypothesize that hyperaccumulator plants will exude a larger quantity of aromatic N and chelating di- and tri-carboxylic acid molecules, while plants that exclude heavy metals from uptake will exude a larger proportion of reduced S containing molecules. This study examines how a variety of techniques can measure the low concentrations of complex organic mixtures exuded by hyperaccumulator and non-hyperaccumulator plants grown in Cd-contaminated soils. Two congeneric plants, Thlaspi caerulescens (Ganges ecotype), and T. caerulescens (Prayon ecotype) were grown in 0.5 kg pots filled with Cd-contaminated field soils from Chicago, IL. Field soils were contaminated as a result of the application of contaminated biosolids in the 1960's and 1970's. Pots were fitted for rhizon soil moisture samplers, micro-lysimeters developed for in situ collection of small volumes in unsaturated soils, prior to planting. Plants were grown for 8 weeks before exudate collection. After the 8 weeks of growth, a pulse-chase isotope tracer method using the C stable isotope, 13C, was employed to differentiate plant-derived compounds from background soil and microbial-derived compounds. Plants were placed in a CO2 impermeable chamber, and the soil

  15. Estimated association between dwelling soil contamination and internal radiation contamination levels after the 2011 Fukushima Daiichi nuclear accident in Japan.

    PubMed

    Tsubokura, Masaharu; Nomura, Shuhei; Sakaihara, Kikugoro; Kato, Shigeaki; Leppold, Claire; Furutani, Tomoyuki; Morita, Tomohiro; Oikawa, Tomoyoshi; Kanazawa, Yukio

    2016-06-29

    Measurement of soil contamination levels has been considered a feasible method for dose estimation of internal radiation exposure following the Chernobyl disaster by means of aggregate transfer factors; however, it is still unclear whether the estimation of internal contamination based on soil contamination levels is universally valid or incident specific. To address this issue, we evaluated relationships between in vivo and soil cesium-137 (Cs-137) contamination using data on internal contamination levels among Minamisoma (10-40 km north from the Fukushima Daiichi nuclear power plant), Fukushima residents 2-3 years following the disaster, and constructed three models for statistical analysis based on continuous and categorical (equal intervals and quantiles) soil contamination levels. A total of 7987 people with a mean age of 55.4 years underwent screening of in vivo Cs-137 whole-body counting. A statistically significant association was noted between internal and continuous Cs-137 soil contamination levels (model 1, p value <0.001), although the association was slight (relative risk (RR): 1.03 per 10 kBq/m(2) increase in soil contamination). Analysis of categorical soil contamination levels showed statistical (but not clinical) significance only in relatively higher soil contamination levels (model 2: Cs-137 levels above 100 kBq/m(2) compared to those <25 kBq/m(2), RR=1.75, p value <0.01; model 3: levels above 63 kBq/m(2) compared to those <11 kBq/m(2), RR=1.45, p value <0.05). Low levels of internal and soil contamination were not associated, and only loose/small associations were observed in areas with slightly higher levels of soil contamination in Fukushima, representing a clear difference from the strong associations found in post-disaster Chernobyl. These results indicate that soil contamination levels generally do not contribute to the internal contamination of residents in Fukushima; thus, individual measurements are essential for the

  16. Land contamination and soil evolution in abandoned mine areas (Italy)

    NASA Astrophysics Data System (ADS)

    Bini, Claudio; Wahsha, Mohammad; Spiandorello, Massimo

    2014-05-01

    In Italy ore research and exploitation are nearly exhausted since the end of the last century, leaving on the land a huge amount of mine waste, therefore provoking evident environmental damage including landscape, vegetation and the food chain, and a potential threat to human health. The increasing environmental consciousness of general population compelled Public Administrators to set down effective legislation acts on this subject (e.g. D.L. 152/2006), and more generally on environmental contamination. In this work we present the results of a survey carried out at several mixed sulphides mine sites in Italy, exploited for at least a millennium, and closed in the '60s of the last century. Biogeochemical analyses carried out on 50 soil profiles (mostly Entisols and Inceptisols) and vegetation in the proximal and distal areas of ore exploitation show metal concentrations overcoming legislation limits on average (Cu up to 3160 mg kg-1 , Pb up to 23600 mg kg-1, Zn up to 1588 mg kg-1, Fe up to 52,30 %). Ni, Cr and Mn concentrations, instead, are generally below the reference levels. Metal concentrations in native vegetation of the examined areas are moderately to highly elevated. Significant amounts of Cu, Pb, Zn in roots of Plantago major and Silene dioica, in leaves of Taraxacum officinale, and Salix spp, have been recorded. Essential elements, in particular, present Translocation Coefficients (TC) >1, with Mn>Zn>Cu>Fe. Toxic elements (Cd, Cr, Pb), instead, present TC<1, suggesting a synergic/antagonist effect to occur among metals and plants, according to their role in mineral nutrition. The results obtained suggest the abandoned mine sites to represent actual natural aboratories where to experiment new opportunities for restoration of anthropogenically contaminated areas, and to study new pedogenetic trends from these peculiar parent materials. Moreover, the examined plants are genetically adapted to naturally metal-enriched soils, and therefore may be utilized in

  17. Remediation of Cd-contaminated soil around metal sulfide mines

    NASA Astrophysics Data System (ADS)

    Lu, Xinzhe; Hu, Xuefeng; Kang, Zhanjun; Luo, Fan

    2017-04-01

    The mines of metal sulfides are widely distributed in the southwestern part of Zhejiang Province, Southeast China. The activities of mining, however, often lead to the severe pollution of heavy metals in soils, especially Cd contamination. According to our field investigations, the spatial distribution of Cd-contaminated soils is highly consistent with the presence of metal sulfide mines in the areas, further proving that the mining activities are responsible for Cd accumulation in the soils. To study the remediation of Cd-contaminated soils, a paddy field nearby large sulfide mines, with soil pH 6 and Cd more than 1.56 mg kg-1, five times higher than the national recommended threshold, was selected. Plastic boards were deeply inserted into soil to separate the field and make experimental plots, with each plot being 4 m×4 m. Six treatments, TK01˜TK06, were designed to study the effects of different experimental materials on remediating Cd-contaminated soils. The treatment of TK01 was the addition of 100 kg zeolites to the plot; TK02, 100 kg apatites; TK03, 100 kg humid manure; TK04, 50 kg zeolites + 50 kg apatites; TK05, 50 kg zeolites + 50 kg humid manure; TK06 was blank control (CK). One month after the treatments, soil samples at the plots were collected to study the possible change of chemical forms of Cd in the soils. The results indicated that these treatments reduced the content of available Cd in the soils effectively, by a decreasing sequence of TK04 (33%) > TK02 (25%) > TK01 (23%) > TK05 (22%) > TK03 (15%), on the basis of CK. Correspondingly, the treatments also reduced the content of Cd in rice grains significantly, by a similar decreasing sequence of TK04 (83%) > TK02 (77%) > TK05 (63%) > TK01 (47%) > TK03 (27%). The content of Cd in the rice grains was 0.071 mg kg-1, 0.094 mg kg-1, 0.159 mg kg-1, 0.22 mg kg-1 and 0.306 mg kg-1, respectively, compared with CK, 0.418 mg kg-1. This experiment suggested that the reduction of available Cd in the soils is

  18. Using biochar for remediation of soils contaminated with heavy metals and organic pollutants.

    PubMed

    Zhang, Xiaokai; Wang, Hailong; He, Lizhi; Lu, Kouping; Sarmah, Ajit; Li, Jianwu; Bolan, Nanthi S; Pei, Jianchuan; Huang, Huagang

    2013-12-01

    Soil contamination with heavy metals and organic pollutants has increasingly become a serious global environmental issue in recent years. Considerable efforts have been made to remediate contaminated soils. Biochar has a large surface area, and high capacity to adsorb heavy metals and organic pollutants. Biochar can potentially be used to reduce the bioavailability and leachability of heavy metals and organic pollutants in soils through adsorption and other physicochemical reactions. Biochar is typically an alkaline material which can increase soil pH and contribute to stabilization of heavy metals. Application of biochar for remediation of contaminated soils may provide a new solution to the soil pollution problem. This paper provides an overview on the impact of biochar on the environmental fate and mobility of heavy metals and organic pollutants in contaminated soils and its implication for remediation of contaminated soils. Further research directions are identified to ensure a safe and sustainable use of biochar as a soil amendment for remediation of contaminated soils.

  19. [Strengthening Effects of Sodium Salts on Washing Kerosene Contaminated Soil with Surfactants].

    PubMed

    Huang, Zhao-lu; Chen, Quan-yuan; Zhou, Juan; Xie, Mo-han

    2015-05-01

    The impact of sodium salt on kerosene contaminated soil washing with surfactants was investigated. The results indicated that sodium silicate greatly enhanced the washing efficiency of SDS. Sodium tartrate can largely enhance the washing efficiency of SDBS and Brij35. Sodium salts can enhance the washing efficiency on kerosene contaminated with TX-100. No significant differences were observed between different sodium salts. Sodium salt of humic acid and sodium silicate had similar enhancement on kerosene contaminated soil washing with saponin. Sodium humate can be a better choice since its application can also improve soil quality. The enhancement of sodium silicate on kerosene contaminated soil washing with Tw-80 increased with the increase of Tw-80 dosage. However, the impact of sodium chloride and sodium tartrate was opposite to sodium silicate. Sodium salts can reduce surface tension and critical micelle concentration of ionic surfactants to enhance the washing. Sodium salts can also reduce re-adsorption of oil to soil with nonionic surfactants to enhance the washing. Kerosene contamination can increase the contact angle of soil, which indicated the increase of hydrophilicity of soil. Washing with surfactants can reduce the hydrophilicitiy of soil according to contact angle measurement, which indicated that kerosene contaminated soil remediation with surfactant can also benefit nutrient and water transportation in the contaminated soil.

  20. Soil contamination by petroleum products. Southern Algerian case

    NASA Astrophysics Data System (ADS)

    Belabbas, Amina; Boutoutaou, Djamel; Segaï, Sofiane; Segni, Ladjel

    2016-07-01

    Contamination of soil by petroleum products is a current problem in several countries in the world. In Algeria, this negative phenomenon is highly remarked in Saharan region. Numerous studies at the University of Ouargla that we will review in this paper, have tried to find an effective solution to eliminate the hydrocarbons from the soil by the technique of "biodegradation" which is a natural process based on microorganisms such as Bacillus megaterium and Pseudomonas aeruginosa. Presence of aboriginal strain Bacillus megaterium in the soil samples with different ages of contamination has shown a strong degradation of pollutants. This strain chosen for its short time of generation which is performing as seen the best yields of elimination of hydrocarbons assessed at 98 % biostimule by biosurfactant, also 98% on a sample wich bioaugmente by urea, and 86 % of the sample which biostimule by nutrient solution. The rate of biodegradation of the contaminated soil by crude oil using the strain Pseudomonas aeruginosa is higher in the presence of biosurfactant 53 % that in his absence 35 %. Another elimination technique wich is washing the contaminated soil's sample by centrifugation in the presence of biosurfactant where The rate of hydrocarbons mobilized after washing soil by centrifugation is of 50 % and 76 % but without centrifugation it was of 46% to 79%. Those processes have great capacity in the remobilization of hydrocarbons and acceleration of their biodegradation; thus, they deserve to be further developed in order to prevent environmental degradation in the region of Ouargla.

  1. Feasibility Process for Remediation of the Crude Oil Contaminated Soil

    NASA Astrophysics Data System (ADS)

    Keum, H.; Choi, H.; Heo, H.; Lee, S.; Kang, G.

    2015-12-01

    More than 600 oil wells were destroyed in Kuwait by Iraqi in 1991. During the war, over 300 oil lakes with depth of up to 2m at more than 500 different locations which has been over 49km2. Therefore, approximately 22 million m3was crude oil contaminated. As exposure of more than 20 years under atmospheric conditions of Kuwait, the crude oil has volatile hydrocarbons and covered heavy oily sludge under the crude oil lake. One of crude oil contaminated soil which located Burgan Oilfield area was collected by Kuwait Oil Company and got by H-plus Company. This contaminated soil has about 42% crude oil and could not biodegraded itself due to the extremely high toxicity. This contaminated soil was separated by 2mm sieve for removal oil sludge ball. Total petroleum hydrocarbons (TPH) was analysis by GC FID and initial TPH concentration was average 48,783 mg/kg. Ten grams of the contaminated soil replaced in two micro reactors with 20mL of bio surfactant produce microorganism. Reactor 1 was added 0.1g powder hemoglobin and other reactor was not added hemoglobin at time 0 day. Those reactors shake 120 rpm on the shaker for 7 days and CO2 produced about 150mg/L per day. After 7 days under the slurry systems, the rest days operated by hemoglobin as primary carbon source for enhanced biodegradation. The crude oil contaminated soil was degraded from 48,783mg/kg to 20,234mg/kg by slurry process and final TPH concentration degraded 11,324mg/kg for 21days. Therefore, highly contaminated soil by crude oil will be combined bio slurry process and biodegradation process with hemoglobin as bio catalytic source. Keywords: crude-oil contaminated soil, bio slurry, biodegradation, hemoglobin ACKOWLEDGEMENTS This project was supported by the Korea Ministry of Environment (MOE) GAIA Program

  2. Apparatus for treatment of soils contaminated with organic pollutants

    DOEpatents

    Wickramanayake, Godage B.

    1993-01-01

    An apparatus for treating soil contaminated by organic compounds wherein an ozone containing gas is treated with acid to increase the stability of the ozone in the soil environment and the treated ozone applied to the contaminated soil in a manner adapted to decompose the organic compounds; one embodiment of the apparatus comprises a means to supply ozone as a gas-ozone mixture, a stability means to treat ozone obtained from the supply and distribution means to apply the stabilized gas-ozone to soil. The soil may be treated in situ or may be removed for treatment and refilled.

  3. Assessing nickel bioavailability in smelter-contaminated soils.

    PubMed

    Everhart, Jeffrey L; McNear, David; Peltier, Edward; van der Lelie, Daniel; Chaney, Rufus L; Sparks, Donald L

    2006-08-31

    Metal contaminants in soil environments derived from industrial pollution have clearly established the need for research on bioavailability and potential health risks. Much research has been conducted on metal sorption in soils. However, there is still a need to better understand the availability of metal contaminants to plants and microbes. Such information will enhance both human health and decisions about remediation efforts. In this study, Welland Loam (Typic epiaquoll) and Quarry Muck (Terric haplohemist) Ni contaminated soils from Port Colborne (Canada) which had been treated and untreated with limestone, were employed in greenhouse and bioavailability studies. These soils varied in pH from 5.1 to 7.5, in organic matter content from 6% to 72%, and in total Ni from 63 to 22,000 mg/kg. Oat (Avena sativa), a nonhyperaccumulator, and Alyssum murale, a hyperaccumulating plant species, were grown on these soils in greenhouse studies for 45 and 120 days, respectively, to estimate Ni accumulation. A Ni specific bacterial biosensor was also used to determine Ni bioavailability, and the results were compared to those from the greenhouse studies and more conventional, indirect chemical extraction techniques (employing MgCl2 and a Sr(NO3)2). Results from the greenhouse, chemical extraction, and biosensor studies suggested that as the pH of the soil was increased with liming, Ni bioavailability decreased. However, the phytoextraction capability of A. murale increased as soil pH increased, which was not the case for A. sativa. Furthermore, the Ni specific bacterial biosensor was successful in predicting Ni bioavailability in the soils and suggested that higher Ni bioavailabilities occur in the soils at pH values of 5.1 and 6. The combination of plant growth, chemical extraction, and bacterial biosensor approaches are recommended for assessing bioavailability of toxic metals.

  4. Remediation of Contaminated Soils By Supercritical Carbon Dioxide Extraction

    NASA Astrophysics Data System (ADS)

    Ferri, A.; Zanetti, M. C.; Banchero, M.; Fiore, S.; Manna, L.

    The contaminants that can be found in soils are many, inorganic, like heavy metals, as well as organic. Among the organic contaminants, oil and coal refineries are responsi- ble for several cases of soil contamination with PAHs (Polycyclic Aromatic Hydrocar- bons). Polynuclear aromatic hydrocarbons (PAHs) have toxic, carcinogenic and mu- tagenic effects. Limits have been set on the concentration of most contaminants, and growing concern is focusing on soil contamination issues. USA regulations set the maximum acceptable level of contamination by PAHs equal to 40 ppm at residential sites and 270 ppm at industrial sites. Stricter values are usually adopted in European Countries. Supercritical carbon dioxide extraction is a possible alternative technology to remove volatile organic compounds from contaminated soils. Supercritical fluid extraction (SFE) offers many advantages over conventional solvent extraction. Super- critical fluids combine gaseous properties as a high diffusion coefficient, and liquid properties as a high solvent power. The solvent power is strongly pressure-dependent near supercritical conditions: selective extractions are possible without changing the solvent. Solute can be separate from the solvent depressurising the system; therefore, it is possible to recycle the solvent and recover the contaminant. Carbon dioxide is frequently used as supercritical fluid, because it has moderate critical conditions, it is inert and available in pure form. In this work, supercritical fluid extraction technology has been used to remove a polynuclear aromatic hydrocarbon from contaminated soils. The contaminant choice for the experiment has been naphthalene since several data are available in literature. G. A. Montero et al. [1] studied soil remediation with supercrit- ical carbon dioxide extraction technology; these Authors have found that there was a mass-transfer limitation. In the extraction vessel, the mass transfer coefficient in- creases with the

  5. Soil Contamination from PCB-Containing Buildings

    PubMed Central

    Herrick, Robert F.; Lefkowitz, Daniel J.; Weymouth, George A.

    2007-01-01

    Background Polychlorinated biphenyls (PCBs) in construction materials, such as caulking used around windows and expansion joints, may constitute a source of PCB contamination in the building interiors and in surrounding soil. Several studies of soil contamination have been conducted around buildings where the caulking has been removed by grinding or scraping. The PCBs in soil may have been generated in the process of removing the caulking, but natural weathering and deterioration of the caulking may have also been a source. Objectives The objectives of this study were to measure PCB levels in soil surrounding buildings where PCB-containing caulk was still in place, and to evaluate the mobility of the PCBs from caulking using the Toxicity Characteristic Leaching Procedure (U.S. Environmental Protection Agency Method 1311). Discussion We found soil PCB contamination ranging from 3.3 to 34 mg/kg around buildings with undisturbed caulking that contained 10,000–36,200 mg/kg PCBs. The results of the Toxicity Characteristic Leaching Procedure (leachate concentrations of 76–288 mg PCB/L) suggest that PCBs in caulking can be mobilized, apparently as complexes with dissolved organic matter that also leach off the caulking material. Conclusions and Recommendations Although these new findings are based on a small sample size, they demonstrate the need for a national survey of PCBs in building materials and in soil surrounding these buildings. Because the buildings constructed during the time the PCB caulking was in use (1960s and 1970s) include schools, hospitals, and apartment buildings, the potential for exposure of children is a particular concern. It is necessary to reconsider the practice of disposing of old PCB caulking removed during building renovations in conventional landfills, given the apparent mobility of PCBs from the caulking material. Disposal of some caulking material in nonhazardous landfills might lead to high PCB levels in landfill leachate. PMID

  6. Assessing the bioavailability and risk from metal contaminated soils and dusts#

    EPA Science Inventory

    Exposure to contaminated soil and dust is an important pathway in human and ecological risk assessment and often is the "risk-driver" for metal contaminated soil. Site-specific soil physical and chemical characteristics, as well as biological factors, determine the bioavailabilit...

  7. Effects of different remediation treatments on crude oil contaminated saline soil.

    PubMed

    Gao, Yong-Chao; Guo, Shu-Hai; Wang, Jia-Ning; Li, Dan; Wang, Hui; Zeng, De-Hui

    2014-12-01

    Remediation of the petroleum contaminated soil is essential to maintain the sustainable development of soil ecosystem. Bioremediation using microorganisms and plants is a promising method for the degradation of crude oil contaminants. The effects of different remediation treatments, including nitrogen addition, Suaeda salsa planting, and arbuscular mycorrhiza (AM) fungi inoculation individually or combined, on crude oil contaminated saline soil were assessed using a microcosm experiment. The results showed that different remediation treatments significantly affected the physicochemical properties, oil contaminant degradation and bacterial community structure of the oil contaminated saline soil. Nitrogen addition stimulated the degradation of total petroleum hydrocarbon significantly at the initial 30d of remediation. Coupling of different remediation techniques was more effective in degrading crude oil contaminants. Applications of nitrogen, AM fungi and their combination enhanced the phytoremediation efficiency of S. salsa significantly. The main bacterial community composition in the crude oil contaminated saline soil shifted with the remediation processes. γ-Proteobacteria, β-Proteobacteria, and Actinobacteria were the pioneer oil-degraders at the initial stage, and Firmicutes were considered to be able to degrade the recalcitrant components at the later stage. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Risk assessment of petroleum-contaminated soil using soil enzyme activities and genotoxicity to Vicia faba.

    PubMed

    Ma, Jun; Shen, Jinglong; Liu, Qingxing; Fang, Fang; Cai, Hongsheng; Guo, Changhong

    2014-05-01

    Pollution caused by petroleum is one of the most serious problems worldwide. To better understand the toxic effects of petroleum-contaminated soil on the microflora and phytocommunity, we conducted a comprehensive field study on toxic effects of petroleum contaminated soil collected from the city of Daqing, an oil producing region of China. Urease, protease, invertase, and dehydrogenase activity were significantly reduced in microflora exposed to contaminated soils compared to the controls, whereas polyphenol oxidase activity was significantly increased (P < 0.05). Soil pH, electrical conductivity, and organic matter content were correlated with total petroleum hydrocarbons (TPHs) and a correlation (P < 0.01) existed between the C/N ratio and TPHs. Protease, invertase and catalase were correlated with TPHs. The Vicia faba micronucleus (MN) test, chromosome aberrant (CA) analyses, and the mitotic index (MI) were used to detect genotoxicity of water extracts of the soil. Petroleum-contaminated samples indicated serious genotoxicity to plants, including decreased index level of MI, increased frequency of MN and CA. The combination of enzyme activities and genotoxicity test via Vicia faba can be used as an important indicator for assessing the impact of TPH on soil ecosystem.

  9. Simulated formation and flow of microemulsions during surfactant flushing of contaminated soil.

    PubMed

    Ouyan, Ying; Cho, Jong Soo; Mansell, Robert S

    2002-01-01

    Contamination of groundwater resources by non-aqueous phase liquids (NAPLs) has become an issue of increasing environmental concern. This study investigated the formation and flow of microemulsions during surfactant flushing of NAPL-contaminated soil using the finite difference model UTCHEM, which was verified with our laboratory experimental data. Simulation results showed that surfactant flushing of NAPLs (i.e., trichloroethylene and tetrachloroethylene) from the contaminated soils was an emulsion-driven process. Formation of NAPL-in-water microemulsions facilitated the removal of NAPLs from contaminated soils. Changes in soil saturation pressure were used to monitor the mobilization and entrapment of NAPLs during surface flushing process. In general, more NAPLs were clogged in soil pores when the soil saturation pressure increased. Effects of aquifer salinity on the formation and flow of NAPL-in-water microemulsions were significant. This study suggests that the formation and flow of NAPL-in-water microemulsions through aquifer systems are complex physical-chemical phenomena that are critical to effective surfactant flushing of contaminated soils.

  10. Phytoremediation of soil contaminated with used lubricating oil using Jatropha curcas.

    PubMed

    Agamuthu, P; Abioye, O P; Aziz, A Abdul

    2010-07-15

    Soil contamination by used lubricating oil from automobiles is a growing concern in many countries, especially in Asian and African continents. Phytoremediation of this polluted soil with non-edible plant like Jatropha curcas offers an environmental friendly and cost-effective method for remediating the polluted soil. In this study, phytoremediation of soil contaminated with 2.5 and 1% (w/w) waste lubricating oil using J. curcas and enhancement with organic wastes [Banana skin (BS), brewery spent grain (BSG) and spent mushroom compost (SMC)] was undertaken for a period of 180 days under room condition. 56.6% and 67.3% loss of waste lubricating oil was recorded in Jatropha remediated soil without organic amendment for 2.5% and 1% contamination, respectively. However addition of organic waste (BSG) to Jatropha remediation rapidly increases the removal of waste lubricating oil to 89.6% and 96.6% in soil contaminated with 2.5% and 1% oil, respectively. Jatropha root did not accumulate hydrocarbons from the soil, but the number of hydrocarbon utilizing bacteria was high in the rhizosphere of the Jatropha plant, thus suggesting that the mechanism of the oil degradation was via rhizodegradation. These studies have proven that J. curcas with organic amendment has a potential in reclaiming hydrocarbon-contaminated soil. 2010 Elsevier B.V. All rights reserved.

  11. 40 CFR 268.49 - Alternative LDR treatment standards for contaminated soil.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... for contaminated soil. 268.49 Section 268.49 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... treatment standards for contaminated soil. (a) Applicability. You must comply with LDRs prior to placing soil that exhibits a characteristic of hazardous waste, or exhibited a characteristic of hazardous...

  12. 40 CFR 268.49 - Alternative LDR treatment standards for contaminated soil.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... for contaminated soil. 268.49 Section 268.49 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... treatment standards for contaminated soil. (a) Applicability. You must comply with LDRs prior to placing soil that exhibits a characteristic of hazardous waste, or exhibited a characteristic of hazardous...

  13. 40 CFR 268.49 - Alternative LDR treatment standards for contaminated soil.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... for contaminated soil. 268.49 Section 268.49 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... treatment standards for contaminated soil. (a) Applicability. You must comply with LDRs prior to placing soil that exhibits a characteristic of hazardous waste, or exhibited a characteristic of hazardous...

  14. 40 CFR 268.49 - Alternative LDR treatment standards for contaminated soil.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... for contaminated soil. 268.49 Section 268.49 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... treatment standards for contaminated soil. (a) Applicability. You must comply with LDRs prior to placing soil that exhibits a characteristic of hazardous waste, or exhibited a characteristic of hazardous...

  15. 40 CFR 268.49 - Alternative LDR treatment standards for contaminated soil.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... for contaminated soil. 268.49 Section 268.49 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... treatment standards for contaminated soil. (a) Applicability. You must comply with LDRs prior to placing soil that exhibits a characteristic of hazardous waste, or exhibited a characteristic of hazardous...

  16. Distribution and Source Identification of Pb Contamination in industrial soil

    NASA Astrophysics Data System (ADS)

    Ko, M. S.

    2017-12-01

    INTRODUCTION Lead (Pb) is toxic element that induce neurotoxic effect to human, because competition of Pb and Ca in nerve system. Lead is classified as a chalophile element and galena (PbS) is the major mineral. Although the Pb is not an abundant element in nature, various anthropogenic source has been enhanced Pb enrichment in the environment after the Industrial Revolution. The representative anthropogenic sources are batteries, paint, mining, smelting, and combustion of fossil fuel. Isotope analysis widely used to identify the Pb contamination source. The Pb has four stable isotopes that are 208Pb, 207Pb, 206Pb, and 204Pb in natural. The Pb is stable isotope and the ratios maintain during physical and chemical fractionation. Therefore, variations of Pb isotope abundance and relative ratios could imply the certain Pb contamination source. In this study, distributions and isotope ratios of Pb in industrial soil were used to identify the Pb contamination source and dispersion pathways. MATERIALS AND METHODS Soil samples were collected at depth 0­-6 m from an industrial area in Korea. The collected soil samples were dried and sieved under 2 mm. Soil pH, aqua-regia digestion and TCLP carried out using sieved soil sample. The isotope analysis was carried out to determine the abundance of Pb isotope. RESULTS AND DISCUSSION The study area was developed land for promotion of industrial facilities. The study area was forest in 1980, and the satellite image show the alterations of land use with time. The variations of land use imply the possibilities of bringing in external contaminated soil. The Pb concentrations in core samples revealed higher in lower soil compare with top soil. Especially, 4 m soil sample show highest Pb concentrations that are approximately 1500 mg/kg. This result indicated that certain Pb source existed at 4 m depth. CONCLUSIONS This study investigated the distribution and source identification of Pb in industrial soil. The land use and Pb

  17. Plant tolerance to diesel minimizes its impact on soil microbial characteristics during rhizoremediation of diesel-contaminated soils.

    PubMed

    Barrutia, O; Garbisu, C; Epelde, L; Sampedro, M C; Goicolea, M A; Becerril, J M

    2011-09-01

    Soil contamination due to petroleum-derived products is an important environmental problem. We assessed the impacts of diesel oil on plants (Trifolium repens and Lolium perenne) and soil microbial community characteristics within the context of the rhizoremediation of contaminated soils. For this purpose, a diesel fuel spill on a grassland soil was simulated under pot conditions at a dose of 12,000 mg diesel kg(-1) DW soil. Thirty days after diesel addition, T. repens (white clover) and L. perenne (perennial ryegrass) were sown in the pots and grown under greenhouse conditions (temperature 25/18 °C day/night, relative humidity 60/80% day/night and a photosynthetic photon flux density of 400 μmol photon m(-2) s(-1)) for 5 months. A parallel set of unplanted pots was also included. Concentrations of n-alkanes in soil were determined as an indicator of diesel degradation. Seedling germination, plant growth, maximal photochemical efficiency of photosystem II (F(v)/F(m)), pigment composition and lipophylic antioxidant content were determined to assess the impacts of diesel on the studied plants. Soil microbial community characteristics, such as enzyme and community-level physiological profiles, were also determined and used to calculate the soil quality index (SQI). The presence of plants had a stimulatory effect on soil microbial activity. L. perenne was far more tolerant to diesel contamination than T. repens. Diesel contamination affected soil microbial characteristics, although its impact was less pronounced in the rhizosphere of L. perenne. Rhizoremediation with T. repens and L. perenne resulted in a similar reduction of total n-alkanes concentration. However, values of the soil microbial parameters and the SQI showed that the more tolerant species (L. perenne) was able to better maintain its rhizosphere characteristics when growing in diesel-contaminated soil, suggesting a better soil health. We concluded that plant tolerance is of crucial importance for the

  18. Phytotreatment of soil contaminated with used lubricating oil using Hibiscus cannabinus.

    PubMed

    Abioye, O P; Agamuthu, P; Abdul Aziz, A R

    2012-04-01

    Soil contamination by hydrocarbons, especially by used lubricating oil, is a growing problem in developing countries, which poses a serious threat to the environment. Phytoremediation of these contaminated soils offers environmental friendly and a cost effective method for their remediation. Hibiscus cannabinus was studied for the remediation of soil contaminated with 2.5 and 1% used lubricating oil and treated with organic wastes [banana skin (BS), brewery spent grain (BSG) and spent mushroom compost (SMC)] for a period of 90 days under natural conditions. Loss of 86.4 and 91.8% used lubricating oil was recorded in soil contaminated with 2.5 and 1% oil and treated with organic wastes respectively at the end of 90 days. However, 52.5 and 58.9% oil loss was recorded in unamended soil contaminated with 2.5 and 1% oil, respectively. The plant did not accumulate hydrocarbon from the soil but shows appreciable accumulation of Fe and Zn in the root and stem of H. cannabinus at the end of the experiment. The first order kinetic rate of uptake of Fe and Zn in H. cannabinus was higher in organic wastes amendment treatments compared to the unamended treatments, which are extremely low. The results of this study suggest that H. cannabinus has a high potential for remediation of hydrocarbon and heavy metal contaminated soil.

  19. Toxicity assessment for petroleum-contaminated soil using terrestrial invertebrates and plant bioassays.

    PubMed

    Hentati, Olfa; Lachhab, Radhia; Ayadi, Mariem; Ksibi, Mohamed

    2013-04-01

    The assessment of soil quality after a chemical or oil spill and/or remediation effort may be measured by evaluating the toxicity of soil organisms. To enhance our understanding of the soil quality resulting from laboratory and oil field spill remediation, we assessed toxicity levels by using earthworms and springtails testing and plant growth experiments. Total petroleum hydrocarbons (TPH)-contaminated soil samples were collected from an oilfield in Sfax, Tunisia. Two types of bioassays were performed. The first assessed the toxicity of spiked crude oil (API gravity 32) in Organization for Economic Co-operation and Development artificial soil. The second evaluated the habitat function through the avoidance responses of earthworms and springtails and the ability of Avena sativa to grow in TPH-contaminated soils diluted with farmland soil. The EC50 of petroleum-contaminated soil for earthworms was 644 mg of TPH/kg of soil at 14 days, with 67 % of the earthworms dying after 14 days when the TPH content reached 1,000 mg/kg. The average germination rate, calculated 8 days after sowing, varied between 64 and 74 % in low contaminated soils and less than 50 % in highly contaminated soils.

  20. Contaminant and other elements in soil (CCQM-K127)

    NASA Astrophysics Data System (ADS)

    Rocio Arvizu Torres, M.; Manzano, J. Velina Lara; Valle Moya, Edith; Horvat, Milena; Jaćimović, Radojko; Zuliani, Tea; Vreča, Polona; Acosta, Osvaldo; Bennet, John; Snell, James; Almeida, Marcelo D.; de Sena, Rodrigo C.; Dutra, Emily S.; Yang, Lu; Li, Haifeng

    2017-01-01

    Non-contaminated soils contain trace and major elements at levels representing geochemical background of the region. The main sources of elements as contaminants/pollutants in soils are mining and smelting activities, fossil fuel combustion, agricultural practices, industrial activities and waste disposal. Contaminated/polluted sites are of great concern and represent serious environmental, health and economic problems. Characterization and identification of contaminated land is the first step in risk assessment and remediation activities. It is well known that soil is a complex matrix with huge variation locally and worldwide. According to the IAWG's five year plan, it is recommended to have a key comparison under the measurement service category of soils and sediments for the year 2015. Currently 13 NMI has claimed calibration and measurement capabilities (CMCs) in category 13 (sediments, soils, ores, and particulates): 29 CMCs in soil and 96 CMCs in sediments. In this regard this is a follow-up comparison in the category 13; wherein three key comparisons have been carried out during the years 2000 (CCQM-K13), 2003 (CCQM-K28) and 2004 (CCQM-K44). Since it is important to update the capabilities of NMIs in this category. CENAM and JSI proposed a key comparison in this category and a pilot study in parallel. The proposed study was agreed by IAWG members, where two soils samples were used in both CCQM-K127 representing a non-contaminated soil with low contents of elements (arsenic, cadmium, iron, lead and manganese), and a contaminated soil with much higher content of selected elements (arsenic, cadmium, iron and lead). This broadens the scope and a degree of complexity of earlier measurements in this field. National metrology institutes (NMIs)/designate institutes (DIs) should, therefore, demonstrate their measurement capabilities of trace and major elements in a wide concentration ranges, representing background/reference sites as well as highly contaminated soils

  1. Bioremediation of petroleum-contaminated soil using aged refuse from landfills.

    PubMed

    Liu, Qingmei; Li, Qibin; Wang, Ning; Liu, Dan; Zan, Li; Chang, Le; Gou, Xuemei; Wang, Peijin

    2018-05-10

    This study explored the effects and mechanisms of petroleum-contaminated soil bioremediation using aged refuse (AR) from landfills. Three treatments of petroleum-contaminated soil (47.28 mg·g -1 ) amended with AR, sterilized aged refuse (SAR) and petroleum-contaminated soil only (as a control) were tested. During 98 days of incubation, changes in soil physicochemical properties, residual total petroleum hydrocarbon (TPH), biodegradation kinetics, enzyme activities and the microbial community were investigated. The results demonstrated that AR was an effective soil conditioner and biostimulation agent that could comprehensively improve the quality of petroleum-contaminated soil and promote microbial growth, with an 74.64% TPH removal rate, 22.36 day half-life for SAR treatment, compared with the control (half-life: 138.63 days; TPH removal rate: 22.40%). In addition, the petroleum-degrading bacteria isolation results demonstrated that AR was also a petroleum-degrading microbial agent containing abundant microorganisms. AR addition significantly improved both the biotic and abiotic conditions of petroleum-contaminated soil without other additives. The cooperation of conditioner addition, biostimulation and bioaugmentation in AR treatment led to better bioremediation effects (half-life: 13.86 days; TPH removal rate: 89.83%). In conclusion, AR amendment is a cost-effective, easy-to-use method facilitating in situ large-scale application while simultaneously recycling huge amounts of AR from landfills. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Bioremediation of cadmium- and zinc-contaminated soil using Rhodobacter sphaeroides.

    PubMed

    Peng, Weihua; Li, Xiaomin; Song, Jingxiang; Jiang, Wei; Liu, Yingying; Fan, Wenhong

    2018-04-01

    Bioremediation using microorganisms is a promising technique to remediate soil contaminated with heavy metals. In this study, Rhodobacter sphaeroides was used to bioremediate soils contaminated with cadmium (Cd) and zinc (Zn). The study found that the treatment reduced the overall bioavailable fractions (e.g., exchangeable and carbonate bound phases) of Cd and Zn. More stable fractions (e.g., Fe-Mn oxide, organic bound, and residual phases (only for Zn)) increased after bioremediation. A wheat seedling experiment revealed that the phytoavailability of Cd was reduced after bioremediation using R. sphaeroides. After bioremediation, the exchangeable phases of Cd and Zn in soil were reduced by as much as 30.7% and 100.0%, respectively; the Cd levels in wheat leaf and root were reduced by as much as 62.3% and 47.2%, respectively. However, when the soils were contaminated with very high levels of Cd and Zn (Cd 54.97-65.33 mg kg -1 ; Zn 813.4-964.8 mg kg -1 ), bioremediation effects were not clear. The study also found that R. sphaeroides bioremediation in soil can enhance the Zn/Cd ratio in the harvested wheat leaf and root overall. This indicates potentially favorable application in agronomic practice and biofortification. Although remediation efficiency in highly contaminated soil was not significant, R. sphaeroides may be potentially and practically applied to the bioremediation of soils co-contaminated by Cd and Zn. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. Soil contamination with emissions of non-ferrous metallurgical plants

    NASA Astrophysics Data System (ADS)

    Vodyanitskii, Yu. N.; Plekhanova, I. O.; Prokopovich, E. V.; Savichev, A. T.

    2011-02-01

    The upper soil horizons are strongly contaminated in the area influenced by the Mid-Urals copper smelter. In the technogenic desert and impact zones, the contents of a number of elements (Cu, Zn, As, Pb, P, and S) by many times exceed their clarke values and the maximum permissible concentrations (or provisional permissible concentrations). The degree of technogeneity (Tg) for these elements is very high in these zones. In the far buffer zone, Tg is about zero for many elements and increases up to Tg = 27-42% for four heavy elements (Cu, Zn, Pb, and As) and up to 81-98% for P and S. The buffer capacity of the humus horizon depends on the soil's location within the technogeochemical anomaly and also on the particular pollutant. In the impact zone, it is equal to 70-77% for lead and arsenic, although other technogenic elements (Zn, Cr, S, and P) are poorly retained and readily migrate into the deeper horizons (the buffer capacity is equal to 14-25%). Nearly all the heavy metals enter the soil in the form of sulfides. The soils in the area affected by the Noril'sk mining and smelting metallurgical enterprise are subdivided into two groups according to the degree of their contamination, i.e., the soils within Noril'sk proper and the soils in its suburbs to a distance of 4-15 km. The strongest soil contamination is recorded in the city: the clarke values are exceeded by 287, 78, 16, 4.1, and 3.5 times for Cu, Ni, Cr, Fe, and S, respectively. The major pollutants enter the soil from the ferruginous slag. The soil's contamination degree is lower in the suburbs, where heavy metal sulfides reach the soils with the aerial emission from the enterprise.

  4. Remediation aspect of microbial changes of plant rhizosphere in mercury contaminated soil.

    PubMed

    Sas-Nowosielska, Aleksandra; Galimska-Stypa, Regina; Kucharski, Rafał; Zielonka, Urszula; Małkowski, Eugeniusz; Gray, Laymon

    2008-02-01

    Phytoremediation, an approach that uses plants to remediate contaminated soil through degradation, stabilization or accumulation, may provide an efficient solution to some mercury contamination problems. This paper presents growth chamber experiments that tested the ability of plant species to stabilize mercury in soil. Several indigenous herbaceous species and Salix viminalis were grown in soil collected from a mercury-contaminated site in southern Poland. The uptake and distribution of mercury by these plants were investigated, and the growth and vitality of the plants through a part of one vegetative cycle were assessed. The highest concentrations of mercury were found at the roots, but translocation to the aerial part also occurred. Most of the plant species tested displayed good growth on mercury contaminated soil and sustained a rich microbial population in the rhizosphere. The microbial populations of root-free soil and rhizosphere soil from all species were also examined. An inverse correlation between the number of sulfur amino acid decomposing bacteria and root mercury content was observed. These results indicate the potential for using some species of plants to treat mercury contaminated soil through stabilization rather than extraction. The present investigation proposes a practical cost-effective temporary solution for phytostabilization of soil with moderate mercury contamination as well as the basis for plant selection.

  5. Development of Canavalia ensiformis in soil contaminated with diesel oil.

    PubMed

    Balliana, A G; Moura, B B; Inckot, R C; Bona, C

    2017-01-01

    Hydrocarbons are the main components of diesel oil and are toxic for the majority of plants. A few plant species, known as phytoremediators, are tolerant of hydrocarbons and can survive the stressful conditions of soils contaminated with diesel oil. Canavalia ensiformis, a plant species that is well distributed throughout the tropics, possesses advantageous features for a potential resistance to soil contamination, such as fast growth and a deep root system. Thus, the aim of the present study was to evaluate the tolerance of C. ensiformis when it was exposed to soil contaminated with diesel oil. Seedlings were subjected to two treatments: contaminated soil (CS) (95 ml/kg of diesel oil) and non-contaminated soil (NCS) for a period of 30 days; its growth, morphology, anatomy, and physiology were analyzed. Despite the high level of toxicity, some individuals were able to survive in CS. These plants had root apical meristems with high levels of mitosis and were able to issue new roots with more developed aerenchyma tissue. Because the surviving plants presented no marks of cellular damage on the organs formed (root and leaves) during the experiment, the species capacity of growth on CS was confirmed. Although, long-term field experiments, applying different contaminant concentrations, should be considered to infer about the species resistance and use as phytoremediator.

  6. Quantifying Diffuse Contamination: Method and Application to Pb in Soil.

    PubMed

    Fabian, Karl; Reimann, Clemens; de Caritat, Patrice

    2017-06-20

    A new method for detecting and quantifying diffuse contamination at the continental to regional scale is based on the analysis of cumulative distribution functions (CDFs). It uses cumulative probability (CP) plots for spatially representative data sets, preferably containing >1000 determinations. Simulations demonstrate how different types of contamination influence elemental CDFs of different sample media. It is found that diffuse contamination is characterized by a distinctive shift of the low-concentration end of the distribution of the studied element in its CP plot. Diffuse contamination can be detected and quantified via either (1) comparing the distribution of the contaminating element to that of an element with a geochemically comparable behavior but no contamination source (e.g., Pb vs Rb), or (2) comparing the top soil distribution of an element to the distribution of the same element in subsoil samples from the same area, taking soil forming processes into consideration. Both procedures are demonstrated for geochemical soil data sets from Europe, Australia, and the U.S.A. Several different data sets from Europe deliver comparable results at different scales. Diffuse Pb contamination in surface soil is estimated to be <0.5 mg/kg for Australia, 1-3 mg/kg for Europe, and 1-2 mg/kg, or at least <5 mg/kg, for the U.S.A. The analysis presented here also allows recognition of local contamination sources and can be used to efficiently monitor diffuse contamination at the continental to regional scale.

  7. Analysis of predictors related to soil contamination in recreational areas of Romania.

    PubMed

    Gagiu, C; Pica, E M; Querol, X; Botezan, C S

    2015-12-01

    Soil contamination in recreational areas can considerably affect children's health, as they are the segment of the population most sensitive to anthropogenic contamination. Soil contamination in recreational areas is influenced by a number of factors such as type and age of the recreational area, nearby traffic intensity, proximity to industrial areas, presence of vegetation, level of usage, treated wood structures, and the extent of maintenance operations carried out in the area. These can most often be observed during a simple site visit. The purpose of the present research is to analyze to which extent the presence of these factors can trigger an alarm signal, highlighting soil contamination in urban recreational areas. In this regard, soil contamination was scaled using the integrated pollution index applied on nine distinctive contaminants (As, Cu, Cd, Zn, Pb, Hg, Co, Ni, Mg) identified using inductively coupled plasma mass spectrometry (ICP-MS). Multiple linear regression analysis was performed in order to assess predictors of soil contamination. The research was carried out in a number of 88 recreational areas, parks, and playgrounds from 19 Romanian cities, revealing the fact that proximity to industrial areas and intensive traffic had statistically significant effects on soil contamination. Furthermore, it was observed that in 78 out of the 88 analyzed locations, the concentrations of contaminants exceeded the guidelines established through national legislation, thus confirming the presumption that high concentrations of contaminants exist in the parks and playgrounds of Romania.

  8. Exoenzyme activity in contaminated soils before and after soil washing: ß-glucosidase activity as a biological indicator of soil health.

    PubMed

    Chae, Yooeun; Cui, Rongxue; Woong Kim, Shin; An, Gyeonghyeon; Jeong, Seung-Woo; An, Youn-Joo

    2017-01-01

    It is essential to remediate or amend soils contaminated with various heavy metals or pollutants so that the soils may be used again safely. Verifying that the remediated or amended soils meet soil quality standards is an important part of the process. We estimated the activity levels of eight soil exoenzymes (acid phosphatase, arylsulfatase, catalase, dehydrogenase, fluorescein diacetate hydrolase, protease, urease, and ß-glucosidase) in contaminated and remediated soils from two sites near a non-ferrous metal smelter, using colorimetric and titrimetric determination methods. Our results provided the levels of activity of soil exoenzymes that indicate soil health. Most enzymes showed lower activity levels in remediated soils than in contaminated soils, with the exception of protease and urease, which showed higher activity after remediation in some soils, perhaps due to the limited nutrients available in remediated soils. Soil exoenzymes showed significantly higher activity in soils from one of the sites than from the other, due to improper conditions at the second site, including high pH, poor nutrient levels, and a high proportion of sand in the latter soil. Principal component analysis revealed that ß-glucosidase was the best indicator of soil ecosystem health, among the enzymes evaluated. We recommend using ß-glucosidase enzyme activity as a prior indicator in estimating soil ecosystem health. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Human exposure to soil contaminants in subarctic Ontario, Canada.

    PubMed

    Reyes, Ellen Stephanie; Liberda, Eric Nicholas; Tsuji, Leonard James S

    2015-01-01

    Chemical contaminants in the Canadian subarctic present a health risk with exposures primarily occurring via the food consumption. Characterization of soil contaminants is needed in northern Canada due to increased gardening and agricultural food security initiatives and the presence of known point sources of pollution. A field study was conducted in the western James Bay Region of Ontario, Canada, to examine the concentrations of polychlorinated biphenyls, dichlorodiphenyltrichloroethane and its metabolites (ΣDDT), other organochlorines, and metals/metalloids in potentially contaminated agriculture sites. Exposure pathways were assessed by comparing the estimated daily intake to acceptable daily intake values. Ninety soil samples were collected at random (grid sampling) from 3 plots (A, B, and C) in Fort Albany (on the mainland), subarctic Ontario, Canada. The contaminated-soil samples were analysed by gas chromatography with an electron capture detector or inductively coupled plasma mass spectrometer. The range of ΣDDT in 90 soil samples was below the limit of detection to 4.19 mg/kg. From the 3 soil plots analysed, Plot A had the highest ΣDDT mean concentration of 1.12 mg/kg, followed by Plot B and Plot C which had 0.09 and 0.01 mg/kg, respectively. Concentrations of other organic contaminants and metals in the soil samples were below the limit of detection or found in low concentrations in all plots and did not present a human health risk. Exposure analyses showed that the human risk was below regulatory thresholds. However, the ΣDDT concentration in Plot A exceeded soil guidelines set out by the Canadian Council of Ministers of the Environment of 0.7 mg/kg, and thus the land should not be used for agricultural or recreational purposes. Both Plots B and C were below threshold limits, and this land can be used for agricultural purposes.

  10. Geochemistry Of Lead In Contaminated Soils: Effects Of Soil Physico-Chemical Properties

    NASA Astrophysics Data System (ADS)

    Saminathan, S.; Sarkar, D.; Datta, R.; Andra, S. P.

    2006-05-01

    Lead (Pb) is an environmental contaminant with proven human health effects. When assessing human health risks associated with Pb, one of the most common exposure pathways typically evaluated is soil ingestion by children. However, bioaccessibility of Pb primarily depends on the solubility and hence, the geochemical form of Pb, which in turn is a function of site specific soil chemistry. Certain fractions of ingested soil-Pb may not dissociate during digestion in the gastro-intestinal tract, and hence, may not be available for transport across the intestinal membrane. Therefore, this study is being currently performed to assess the geochemical forms and bioaccessibility of Pb in soils with varying physico-chemical properties. In order to elucidate the level of Pb that can be ingested and assimilated by humans, an in-vitro model that simulates the physiological conditions of the human digestive system has been developed and is being used in this study. Four different types of soils from the Immokalee (an acid sandy soil with minimal Pb retention potential), Millhopper (a sandy loam with high Fe/Al content), Pahokee (a muck soil with more than 80% soil organic matter), and Tobosa series (an alkaline soil with high clay content) were artificially contaminated with Pb as lead nitrate at the rate equivalent to 0, 400, 800, and 1200 mg/kg dry soil. Analysis of soils by a sequential extraction method at time zero (immediately after spiking) showed that Immokalee and Millhopper soils had the highest amount of Pb in exchangeable form, whereas Pahokee and Tobosa soils had higher percentages of carbonate-bound and Fe/Al-bound Pb. The results of in-vitro experiment at time zero showed that majority of Pb was dissolved in the acidic stomach environment in Immokalee, Millhopper, and Tobosa, whereas it was in the intestinal phase in Pahokee soils. Because the soil system is not in equilibrium at time zero, the effect of soil properties on Pb geochemistry is not clear as yet. The

  11. Development of Ecological Toxicity and Biomagnification Data for Explosives Contaminants in Soil

    DTIC Science & Technology

    2003-07-01

    explosive contaminated soil leachates to Daphnia magna using an adapted toxicity characteristic leaching procedure. U.S. Army Chemical and Biological...1993) Toxicity determination of explosive contaminated soil leachates to Daphnia magna using an adapted toxicity characteristic leaching procedure...Sadusky, M. (1993). Toxicity determination of explosive contaminated soil leachates to Daphnia magna using C-46 an adapted toxicity

  12. Microemulsion-enhanced remediation of soils contaminated with organochlorine pesticides.

    PubMed

    Zhang, Yanlin; Wong, Jonathan W C; Zhao, Zhenyong; Selvam, Ammaiyappan

    2011-12-01

    Soil contaminated by organic pollutants, especially chlorinated aromatic compounds such as DDT (1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane), is an environmental concern because of the strong sorption of organochlorine pesticide onto the soil matrix and persistence in the environment. The remediation of organochlorine pesticide contaminated soils through microemulsion is an innovative technology to expedite this process. The remediation efficiency was evaluated by batch experiments through studying the desorption of DDT and hexachlorocyclohexane (y-HCH) and sorption of microemulsion composed of Triton X-100, 1-pentanol and linseed oil in the soil-surfactant-water suspension system. The reduction of desorption efficiency caused by the sorption loss of microemulsion components onto the soil could be corrected by the appropriate adjustment of C/S (Cosurfactant/Surfactant) and O/S (Oil/Surfactant) ratio. The C/S and O/S ratios of 1:2 and 3:20 were suitable to desorb DDT and gamma-HCH from the studied soils because of the lower sorption of Triton X-100 onto the soil. Inorganic salts added in microemulsion increased the pesticides desorption efficiency of pesticides and calcium chloride has a stronger ability to enhance the desorption of DDT than sodium chloride. From the remediation perspective, the balance of surfactant or cosurfactant sorbed to soil and desorption efficiency should be taken into consideration to enhance the remediation of soils contaminated by organochlorine pesticides.

  13. Soil contamination standards for protection of personnel

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rittmann, P.D.

    1998-04-16

    The objective of this report is to recommend soil contamination levels that will ensure that radionuclide intakes by unprotected workers are likely to give internal doses below selected dose limits during the working year. The three internal dose limits are 1, 100, and 500 mrem per year. In addition, photon, beta, and alpha instrument readings are estimated for these soil concentration limits. Two exposure pathways are considered: the first is inhalation of resuspended dust and the second is ingestion of trace amounts of soil. In addition, radioactive decay and ingrowth of progeny during the year of exposure is included. Externalmore » dose from the soil contamination is not included because monitoring and control of external exposures is carried out independently from internal exposures, which are the focus of this report. The methods used are similar to those used by Carbaugh and Bihl (1993) to set bioassay criteria for such workers.« less

  14. Low-concentration tailing and subsequent quicklime-enhanced remediation of volatile chlorinated hydrocarbon-contaminated soils by mechanical soil aeration.

    PubMed

    Ma, Yan; Du, Xiaoming; Shi, Yi; Xu, Zhu; Fang, Jidun; Li, Zheng; Li, Fasheng

    2015-02-01

    Mechanical soil aeration has long been regarded as an effective ex-situ remediation technique and as suitable for remediation of large-scale sites contaminated by volatile organic compounds (VOCs) at low cost. However, it has been reported that the removal efficiency of VOCs from soil is relatively low in the late stages of remediation, in association with tailing. Tailing may extend the remediation time required; moreover, it typically results in the presence of contaminants residues at levels far exceeding regulations. In this context, the present study aimed to discuss the tailing that occurs during the process of remediation of soils contaminated artificially with volatile chlorinated hydrocarbons (VCHs) and to assess possible quicklime-enhanced removal mechanisms. The results revealed the following conclusions. First, temperature and aeration rate can be important controls on both the timing of appearance of tailing and the levels of residual contaminants. Furthermore, the addition of quicklime to soil during tailing can reduce the residual concentrations rapidly to below the remedial target values required for site remediation. Finally, mechanical soil aeration can be enhanced using quicklime, which can improve the volatilization of VCHs via increasing soil temperature, reducing soil moisture, and enhancing soil permeability. Our findings give a basic understanding to the elimination of the tailing in the application of mechanical soil aeration, particularly for VOCs-contaminated soils. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Environmental projects. Volume 14: Removal of contaminated soil and debris

    NASA Technical Reports Server (NTRS)

    Kushner, Len

    1992-01-01

    Numerous diverse activities at the Goldstone Deep Space Communications Complex (GDSCC) are carried out in support of six parabolic dish antennas. Some of these activities can result in possible spills or leakages of hazardous materials and wastes stored both above ground in steel drums and below ground in underground storage tanks (UST's). These possible leaks or spills, along with the past practice of burial of solid debris and waste in trenches and pits, could cause local subsurface contamination of the soil. In 1987, the Jet Propulsion Laboratory (JPL), retained Engineering-Science, Inc. (E-S), Pasadena, California, to identify the specific local areas within the GDSCC with subsurface soil contamination. The E-S study determined that some of the soils at the Apollo Site and the Mars Site were contaminated with hydrocarbons, while soil at a nonhazardous waste dumpsite at the Mojave Base site was contaminated with copper. This volume is a JPL-expanded version of the PE209 E-S report, and it also reports that all subsurface contaminated soils at the GDSCC were excavated, removed, and disposed of in an environmentally acceptable way, and the excavations were backfilled and covered in accordance with accepted Federal, State, and local environmental rules and regulations.

  16. Remediation of contaminated soils by biotechnology with nanomaterials: bio-behavior, applications, and perspectives.

    PubMed

    Gong, Xiaomin; Huang, Danlian; Liu, Yunguo; Peng, Zhiwei; Zeng, Guangming; Xu, Piao; Cheng, Min; Wang, Rongzhong; Wan, Jia

    2018-05-01

    Soil contamination caused by heavy metals and organic pollutants has drawn world-wide concern. Biotechnology has been applied for many years to the decontamination of soils polluted with organic and inorganic contaminants, and novel nanomaterials (NMs) has attracted much concern due to their high capacity for the removal/stabilization/degradation of pollutants. Recently, developing advanced biotechnology with NMs for the remediation of contaminated soils has become a hot research topic. Some researchers found that bioremediation efficiency of contaminated soils was enhanced by the addition of NMs, while others demonstrated that the toxicity of NMs to the organism negatively influenced the repair capacity of polluted soils. This paper reviews the application of biotechnology and NMs in soil remediation, and further provides a critical view of the effects of NMs on the phytoremediation and micro-remediation of contaminated soils. This review also discusses the future research needs for the combined application of biotechnology and NMs in soil remediation.

  17. Abundance and diversity of Archaea in heavy-metal-contaminated soils.

    PubMed

    Sandaa, R A; Enger, O; Torsvik, V

    1999-08-01

    The impact of heavy-metal contamination on archaean communities was studied in soils amended with sewage sludge contaminated with heavy metals to varying extents. Fluorescent in situ hybridization showed a decrease in the percentage of Archaea from 1.3% +/- 0.3% of 4', 6-diamidino-2-phenylindole-stained cells in untreated soil to below the detection limit in soils amended with heavy metals. A comparison of the archaean communities of the different plots by denaturing gradient gel electrophoresis revealed differences in the structure of the archaean communities in soils with increasing heavy-metal contamination. Analysis of cloned 16S ribosomal DNA showed close similarities to a unique and globally distributed lineage of the kingdom Crenarchaeota that is phylogenetically distinct from currently characterized crenarchaeotal species.

  18. Mobilization of hydrophobic contaminants from soils by enzymatic depolymerization of soil organic matter.

    PubMed

    Wicke, Daniel; Reemtsma, Thorsten

    2010-02-01

    The effect of hydrolytic exoenzymes on the release of hydrophobic organic contaminants (HOC) from two different surface soils was studied in laboratory batch experiments. Incubation of the soils with cellulase with an activity fivefold above the inherent soil activity enhanced the release of hydrophobic contaminants (polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCB) and hydroxylated PCB) by 40-200%. Xylanase and invertase did not show measurable effects at comparable relative activity levels. This suggests that cellulose substructures are important for the retention of HOC in soil organic matter (SOM). Hydrolytic exoenzymes, and the microorganisms that release them, contribute to the mobilization of HOC from soil, by shifting the sorption equilibrium in the course of SOM transformation into dissolved organic matter or by facilitating HOC diffusion as a consequence of reduced rigidity of SOM. We conclude that not only biodegradation but also sorption and desorption of HOC in soil can be influenced by (micro-) biology and the factors that determine its activity.

  19. BIOREMEDIATION OF CONTAMINATED SURFACE SOILS

    EPA Science Inventory

    Biological remediation of soils contaminated with organic chemicals is an alternative treatment technology that can often meet the goal of achieving a permanent clean-up remedy at hazardous waste sites, as encouraged by the U.S. Environmental Protection Agency (U.S. EPA) for impl...

  20. Electroremediation of PCB contaminated soil combined with iron nanoparticles: Effect of the soil type.

    PubMed

    Gomes, Helena I; Dias-Ferreira, Celia; Ottosen, Lisbeth M; Ribeiro, Alexandra B

    2015-07-01

    Polychlorinated biphenyls (PCB) are carcinogenic and persistent organic pollutants that accumulate in soils and sediments. Currently, there is no cost-effective and sustainable remediation technology for these contaminants. In this work, a new combination of electrodialytic remediation and zero valent iron particles in a two-compartment cell is tested and compared to a more conventional combination of electrokinetic remediation and nZVI in a three-compartment cell. In the new two-compartment cell, the soil is suspended and stirred simultaneously with the addition of zero valent iron nanoparticles. Remediation experiments are made with two different historically PCB contaminated soils, which differ in both soil composition and contamination source. Soil 1 is a mix of soils with spills of transformer oils, while Soil 2 is a superficial soil from a decommissioned school where PCB were used as windows sealants. Saponin, a natural surfactant, was also tested to increase the PCB desorption from soils and enhance dechlorination. Remediation of Soil 1 (with highest pH, carbonate content, organic matter and PCB concentrations) obtained the maximum 83% and 60% PCB removal with the two-compartment and the three-compartment cell, respectively. The highest removal with Soil 2 were 58% and 45%, in the two-compartment and the three-compartment cell, respectively, in the experiments without direct current. The pH of the soil suspension in the two-compartment treatment appears to be a determining factor for the PCB dechlorination, and this cell allowed a uniform distribution of the nanoparticles in the soil, while there was iron accumulation in the injection reservoir in the three-compartment cell. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Bioremediation of industrially contaminated soil using compost and plant technology.

    PubMed

    Taiwo, A M; Gbadebo, A M; Oyedepo, J A; Ojekunle, Z O; Alo, O M; Oyeniran, A A; Onalaja, O J; Ogunjimi, D; Taiwo, O T

    2016-03-05

    Compost technology can be utilized for bioremediation of contaminated soil using the active microorganisms present in the matrix of contaminants. This study examined bioremediation of industrially polluted soil using the compost and plant technology. Soil samples were collected at the vicinity of three industrial locations in Ogun State and a goldmine site in Iperindo, Osun State in March, 2014. The compost used was made from cow dung, water hyacinth and sawdust for a period of twelve weeks. The matured compost was mixed with contaminated soil samples in a five-ratio pot experimental design. The compost and contaminated soil samples were analyzed using the standard procedures for pH, electrical conductivity (EC), organic carbon (OC), total nitrogen (TN), phosphorus, exchangeable cations (Na, K, Ca and Mg) and heavy metals (Fe, Mn, Cu, Zn and Cr). Kenaf (Hibiscus cannabinus) seeds were also planted for co-remediation of metals. The growth parameters of Kenaf plants were observed weekly for a period of one month. Results showed that during the one-month remediation experiment, treatments with 'compost-only' removed 49 ± 8% Mn, 32 ± 7% Fe, 29 ± 11% Zn, 27 ± 6% Cu and 11 ± 5% Cr from the contaminated soil. On the other hand, treatments with 'compost+plant' remediated 71 ± 8% Mn, 63 ± 3% Fe, 59 ± 11% Zn, 40 ± 6% Cu and 5 ± 4% Cr. Enrichment factor (EF) of metals in the compost was low while that of Cu (EF=7.3) and Zn (EF=8.6) were high in the contaminated soils. Bioaccumulation factor (BF) revealed low metal uptake by Kenaf plant. The growth parameters of Kenaf plant showed steady increments from week 1 to week 4 of planting. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Bioremediation of oil-contaminated soils by composting

    NASA Astrophysics Data System (ADS)

    Golodyaev, G. P.; Kostenkov, N. M.; Oznobikhin, V. I.

    2009-08-01

    Composting oil-contaminated soils under field conditions with the simultaneous optimization of their physicochemical and agrochemical parameters revealed the high efficiency of the soil purification, including that from benz[a]pyrene. The application of fertilizers and lime favored the intense development of indigenous microcenoses and the effective destruction of the oil. During the 95-day experimental period, the average daily rate of the oil decomposition was 157 mg/kg of soil. After the completion of the process, the soil became ecologically pure.

  3. Plasmid-Mediated Bioaugmentation for the Bioremediation of Contaminated Soils

    PubMed Central

    Garbisu, Carlos; Garaiyurrebaso, Olatz; Epelde, Lur; Grohmann, Elisabeth; Alkorta, Itziar

    2017-01-01

    Bioaugmentation, or the inoculation of microorganisms (e.g., bacteria harboring the required catabolic genes) into soil to enhance the rate of contaminant degradation, has great potential for the bioremediation of soils contaminated with organic compounds. Regrettably, cell bioaugmentation frequently turns into an unsuccessful initiative, owing to the rapid decrease of bacterial viability and abundance after inoculation, as well as the limited dispersal of the inoculated bacteria in the soil matrix. Genes that encode the degradation of organic compounds are often located on plasmids and, consequently, they can be spread by horizontal gene transfer into well-established, ecologically competitive, indigenous bacterial populations. Plasmid-mediated bioaugmentation aims to stimulate the spread of contaminant degradation genes among indigenous soil bacteria by the introduction of plasmids, located in donor cells, harboring such genes. But the acquisition of plasmids by recipient cells can affect the host’s fitness, a crucial aspect for the success of plasmid-mediated bioaugmentation. Besides, environmental factors (e.g., soil moisture, temperature, organic matter content) can play important roles for the transfer efficiency of catabolic plasmids, the expression of horizontally acquired genes and, finally, the contaminant degradation activity. For plasmid-mediated bioaugmentation to be reproducible, much more research is needed for a better selection of donor bacterial strains and accompanying plasmids, together with an in-depth understanding of indigenous soil bacterial populations and the environmental conditions that affect plasmid acquisition and the expression and functioning of the catabolic genes of interest. PMID:29062312

  4. In Situ Evaluation of Crop Productivity and Bioaccumulation of Heavy Metals in Paddy Soils after Remediation of Metal-Contaminated Soils.

    PubMed

    Kim, Shin Woong; Chae, Yooeun; Moon, Jongmin; Kim, Dokyung; Cui, Rongxue; An, Gyeonghyeon; Jeong, Seung-Woo; An, Youn-Joo

    2017-02-15

    Soils contaminated with heavy metals have been reused for agricultural, building, and industrial uses following remediation. This study assesses plant growth and bioaccumulation of heavy metals following remediation of industrially contaminated soil. The soil was collected from a field site near a nonferrous smelter and was subjected to laboratory- and field-scale studies. Soil from the contaminated site was remediated by washing with acid or mixed with soil taken from a distant uncontaminated site. The activities of various soil exoenzymes, the rate of plant growth, and the bioaccumulations of six heavy metals were measured to assess the efficacy of these bioremediation techniques. Growth of rice (Oryza sativa) was unaffected in acid-washed soil or the amended soil compared to untreated soil from the contaminated site. The levels of heavy metals in the rice kernels remained within safe limits in treated and untreated soils. Rice, sorghum (Sorghum bicolor), and wheat (Triticum aestivum) cultivated in the same soils in the laboratory showed similar growth rates. Soil exoenzyme activities and crop productivity were not affected by soil treatment in field experiments. In conclusion, treatment of industrially contaminated soil by acid washing or amendment did not adversely affect plant productivity or lead to increased bioaccumulation of heavy metals in rice.

  5. Aided Phytostabilization of Copper Contaminated Soils with L. Perenne and Mineral Sorbents as Soil Amendments

    NASA Astrophysics Data System (ADS)

    Radziemska, Maja

    2017-09-01

    The present study was designed to assess phytostabilization strategies for the treatment of soil co-contaminated by increasing levels of copper with the application mineral amendments (chalcedonite, zeolite, dolomite). From the results it will be possible to further elucidate the benefits or potential risks derived from the application of different types of mineral amendments in the remediation of a copper contaminated soil. A glasshouse pot experiment was designed to evaluate the potential use of different amendments as immobilizing agents in the aided phytostabilization of Cu-contaminated soil using ryegrass (Lolium perenne L.). The content of trace elements in plants and total in soil, were determined using the method of spectrophotometry. All of the investigated element contents in the tested parts of L. perenne were significantly different in the case of applying mineral amendments to the soil, as well as increasing concentrations of copper. The greatest average above-ground biomass was observed for soil amended with chalcedonite. In this experiment, all analyzed metals accumulated predominantly in the roots of the tested plant. In general, applying mineral amendments to soil contributed to decreased levels of copper concentrations.

  6. Oral bioavailability of cyclotrimethylenetrinitramine (RDX) from contaminated site soils in rats.

    PubMed

    Crouse, Lee C B; Michie, Mark W; Major, Michael A; Leach, Glenn J; Reddy, Gunda

    2008-01-01

    Cyclotrimethylenetrinitramine (RDX), a commonly used military explosive, was detected as a contaminant of soil and water at Army facilities and ranges. This study was conducted to determine the relative oral bioavailability of RDX in contaminated soil and to develop a method to derive bioavailability adjustments for risk assessments using rodents. Adult male Sprague-Dawley rats preimplanted with femoral artery catheters were dosed orally with gelatin capsules containing either pure RDX or an equivalent amount of RDX in contaminated soils from Louisiana Army Ammunition Plant (LAAP) (2300 microg/g of soil) or Fort Meade (FM) (670 microg/g of soil). After dosing rats, blood samples were collected from catheters at 2-h intervals (2, 4, 6, 8, 10, and 12) and at 24 and 48 h. RDX levels in the blood were determined by gas chromatography. The results show that the peak absorption of RDX in blood was 6 h for neat RDX (1.24 mg/kg) and for RDX from contaminated soil (1.24 mg/kg) of LAAP. Rats dosed with RDX-contaminated FM soil (0.2 mg/kg) showed peak levels of RDX in blood at 6 h, whereas their counterparts that received an identical dose (0.2 mg/kg) of neat RDX showed peak absorption at 4 h. The blood levels of absorbed RDX from LAAP soil were about 25% less than for neat RDX, whereas the bioavailability of RDX from FM soils was about 15% less than that seen in rats treated with neat RDX (0.2 mg/kg). The oral bioavailability in rats fed RDX in LAAP soil and the FM soil was reduced with the neat compound but decrease in bioavailability varied with the soil type.

  7. Micro-scale investigations on soil heterogeneity: Impacts on Zn retention and uptake in Zn contaminated soils

    USDA-ARS?s Scientific Manuscript database

    Metal contaminants in soils can persist for millennia, causing lasting negative impacts on local ecosystems. Long-term contaminant bioavailability is related to soil pH and the strength and stability of their solid phase associations. We combined physical density separation with synchrotron-based mi...

  8. Remediation of arsenic-contaminated soils and groundwaters

    DOEpatents

    Peters, Robert W.; Frank, James R.; Feng, Xiandong

    1998-01-01

    An in situ method for extraction of arsenic contaminants from a soil medium and remediation of the medium including contacting the medium with an extractant solution, directing the solution within and through the medium, and collecting the solution and contaminants. The method can also be used for arsenate and/or arsenite removal.

  9. Evaluating specificity of sequential extraction for chemical forms of lead in artificially-contaminated and field-contaminated soils.

    PubMed

    Tai, Yiping; McBride, Murray B; Li, Zhian

    2013-03-30

    In the present study, we evaluated a commonly employed modified Bureau Communautaire de Référence (BCR test) 3-step sequential extraction procedure for its ability to distinguish forms of solid-phase Pb in soils with different sources and histories of contamination. When the modified BCR test was applied to mineral soils spiked with three forms of Pb (pyromorphite, hydrocerussite and nitrate salt), the added Pb was highly susceptible to dissolution in the operationally-defined "reducible" or "oxide" fraction regardless of form. When three different materials (mineral soil, organic soil and goethite) were spiked with soluble Pb nitrate, the BCR sequential extraction profiles revealed that soil organic matter was capable of retaining Pb in more stable and acid-resistant forms than silicate clay minerals or goethite. However, the BCR sequential extraction for field-collected soils with known and different sources of Pb contamination was not sufficiently discriminatory in the dissolution of soil Pb phases to allow soil Pb forms to be "fingerprinted" by this method. It is concluded that standard sequential extraction procedures are probably not very useful in predicting lability and bioavailability of Pb in contaminated soils. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Soil slurry reactors for the assessment of contaminant biodegradation

    NASA Astrophysics Data System (ADS)

    Toscano, G.; Colarieti, M. L.; Greco, G.

    2012-04-01

    Slurry reactors are frequently used in the assessment of feasibility of biodegradation in natural soil systems. The rate of contaminant removal is usually quantified by zero- or first-order kinetics decay constants. The significance of such constants for the evaluation of removal rate in the field could be questioned because the slurry reactor is a water-saturated, well-stirred system without resemblance with an unsaturated fixed bed of soil. Nevertheless, a kinetic study with soil slurry reactors can still be useful by means of only slightly more sophisticated kinetic models than zero-/first-order decay. The use of kinetic models taking into account the role of degrading biomass, even in the absence of reliable experimental methods for its quantification, provides further insight into the effect of nutrient additions. A real acceleration of biodegradation processes is obtained only when the degrading biomass is in the growth condition. The apparent change in contaminant removal course can be useful to diagnose biomass growth without direct biomass measurement. Even though molecular biology techniques are effective to assess the presence of potentially degrading microorganism in a "viable-but-nonculturable" state, the attainment of conditions for growth is still important to the development of enhanced remediation techniques. The methodology is illustrated with reference to data gathered for two test sites, Oslo airport Gardermoen in Norway (continuous contamination by aircraft deicing fluids) and the Trecate site in Italy (aged contamination by crude oil spill). This research is part of SoilCAM project (Soil Contamination, Advanced integrated characterisation and time-lapse Monitoring 2008-2012, EU-FP7).

  11. Application of carbon nanotubes to immobilize heavy metals in contaminated soils

    NASA Astrophysics Data System (ADS)

    Matos, Martim P. S. R.; Correia, António Alberto S.; Rasteiro, Maria G.

    2017-04-01

    The contamination of soils with heavy metals is a growing concern in modern societies. To avoid the spread of contamination, soil stabilization techniques can be applied mixing materials with the soil in order to partially immobilize heavy metals. Carbon nanotubes (CNTs) are nanomaterials known for its exceptional properties, like high surface area and adsorption capacity. Due to these unique properties, the potential use of CNTs in heavy metal contaminated water has been studied, with very satisfactory results; however, their application in contaminated soils is practically unexplored. This experimental work is focused on studying the potential of using CNTs in soil remediation, especially to immobilize the heavy metals ions: lead (Pb2+), copper (Cu2+), nickel (Ni2+), and zinc (Zn2+), commonly present in contaminated soils. In order to avoid CNT agglomeration, which originates the loss of their beneficial properties, an aqueous suspension of CNTs was prepared using a non-ionic surfactant combined with ultrasonic energy to promote CNTs dispersion. Then, the soil, with and without the addition of CNTs, was subjected to adsorption tests to evaluate the CNT capacity to improve heavy metal immobilization. To validate the adsorption test results, permeability tests were executed, simulating the conditions of a real-case scenario. The results obtained led to the conclusion that the addition of a small amount of dispersed CNTs can successfully increase the adsorption capacity of the soil and consequently improve the immobilization of heavy metals in the soil matrix. The immobilization percentage varies with the different heavy metals under study.

  12. Hydrolytic and ligninolytic enzyme activities in the Pb contaminated soil inoculated with litter-decomposing fungi.

    PubMed

    Kähkönen, Mika A; Lankinen, Pauliina; Hatakka, Annele

    2008-06-01

    The impact of Pb contamination was tested to five hydrolytic (beta-glucosidase, beta-xylosidase, beta-cellobiosidase, alpha-glucosidase and sulphatase) and two ligninolytic (manganese peroxidase, MnP and laccase) enzyme activities in the humus layer in the forest soil. The ability of eight selected litter-degrading fungi to grow and produce extracellular enzymes in the heavily Pb (40 g Pb of kg ww soil(-1)) contaminated and non-contaminated soil in the non-sterile conditions was also studied. The Pb content in the test soil was close to that of the shooting range at Hälvälä (37 g Pb of kg ww soil(-1)) in Southern Finland. The fungi were Agaricus bisporus, Agrocybe praecox, Gymnopus peronatus, Gymnopilus sapineus, Mycena galericulata, Gymnopilus luteofolius, Stropharia aeruginosa and Stropharia rugosoannulata. The Pb contamination (40 g Pb of kg ww soil(-1)) was deleterious to all five studied hydrolytic enzyme activities after five weeks of incubation. All five hydrolytic enzyme activities were significantly higher in the soil than in the extract of the soil indicating that a considerable part of enzymes were particle bound in the soils. Hydrolytic enzyme activities were higher in the non-contaminated soil than in the Pb contaminated soil. Fungal inocula increased the hydrolytic enzyme activities beta-cellobiosidase and beta-glucosidase in non-contaminated soils. All five hydrolytic enzyme activities were similar with fungi and without fungi in the Pb contaminated soil. This was in line that Pb contamination (40 g Pb of kg ww soil(-1)) depressed the growth of all fungi compared to those grown without Pb in the soil. Laccase and MnP activities were low in both Pb contaminated and non-contaminated soil cultures. MnP activities were higher in soil cultures containing Pb than without Pb. Our results showed that Pb in the shooting ranges decreased fungal growth and microbial functioning in the soil.

  13. Integrating Electrokinetic and Bioremediation Process for Treating Oil Contaminated Low Permeability Soil

    NASA Astrophysics Data System (ADS)

    Ramadan, Bimastyaji Surya; Effendi, Agus Jatnika; Helmy, Qomarudin

    2018-02-01

    Traditional oil mining activities always ignores environmental regulation which may cause contamination in soil and environment. Crude oil contamination in low-permeability soil complicates recovery process because it requires substantial energy for excavating and crushing the soil. Electrokinetic technology can be used as an alternative technology to treat contaminated soil and improve bioremediation process (biostimulation) through transfer of ions and nutrient that support microorganism growth. This study was conducted using a combination of electrokinetic and bioremediation processes. Result shows that the application of electrokinetic and bioremediation in low permeability soils can provide hydrocarbon removal efficiency up to 46,3% in 7 days operation. The highest amount of microorganism can be found in 3-days operation, which is 2x108 CFU/ml using surfactant as flushing fluid for solubilizing hydrocarbon molecules. Enhancing bioremediation using electrokinetic process is very potential to recover oil contaminated low permeability soil in the future.

  14. Ecological risk assessment in legislation on contaminated soil in The Netherlands.

    PubMed

    Boekhold, Alexandra E

    2008-12-01

    Recently the Dutch soil policy was revised including new rules for the relocation of contaminated soil and dredged soil material. With these rules, new methods for ecotoxicological risk assessment were implemented. One of the new methods is the assessment of the local toxic pressure of mixtures, also known as the ms-PAF- method, based on the Species Sensitivity Distribution concept. The ms-PAF method is applied for risk assessment of spreading of dredged soil material on adjacent land. Its application will possibly be extended to the derivation of local soil quality standards relevant in the context of soil relocation. The application of the local toxic pressure will probably increase the reuse of contaminated soil and dredged soil material and hence will reduce the amounts considered to be unfit for use. With this method, local ecological risk limits are derived using pore water concentrations and effects on water organisms. Pore water concentrations are subsequently transferred to total soil concentrations using empirical relationships. The methodology does not impose upper limits for total soil concentrations. In soils with a high sorption capacity, total soil concentrations that are considered to be acceptable may be several times higher than the current Dutch intervention values. The possible introduction of the ms-PAF method will open the door to local soil relocation with soils containing large amounts of (semi-permanently soil bound) contaminants. Since the ms-PAF method is not yet properly validated, the lack of evidence of ecological effects using models like the ms-PAF method cannot be regarded as an indication for the absence of effects in reality. The Dutch soil quality decree would gain environmental ambition when the ms-PAF method was combined with a realistic upper limit on total soil concentrations. This would prevent contamination of land by means of soil relocation.

  15. Remediation of lead contaminated soil by biochar-supported nano-hydroxyapatite.

    PubMed

    Yang, Zhangmei; Fang, Zhanqiang; Zheng, Liuchun; Cheng, Wen; Tsang, Pokeung Eric; Fang, Jianzhang; Zhao, Dongye

    2016-10-01

    In this study, a high efficiency and low cost biochar-supported nano-hydroxyapatite (nHAP@BC) material was used in the remediation of lead (Pb)-contaminated soil. The remediation effect of nHAP@BC on Pb-contaminated soil was evaluated through batch experiments. The stability, bioaccessibility of Pb in the soil and the change in soil characteristics are discussed. Furthermore, the effects of the amendments on the growth of cabbage mustard seedlings and the accumulation of Pb were studied. The results showed that the immobilization rates of Pb in the soil were 71.9% and 56.8%, respectively, after a 28 day remediation using 8% nHAP and nHAP@BC materials, and the unit immobilization amount of nHAP@BC was 5.6 times that of nHAP, indicating that nHAP@BC can greatly reduce the cost of remediation of Pb in soil. After the nHAP@BC remediation, the residual fraction Pb increased by 61.4%, which greatly reduced the bioaccessibility of Pb in the soil. Moreover, nHAP@BC could effectively reduce the accumulation of Pb in plants by 31.4%. Overall, nHAP@BC can effectively remediate Pb-contaminated soil and accelerate the recovery of soil fertility. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Assessing soil and groundwater contamination in a metropolitan redevelopment project.

    PubMed

    Yun, Junki; Lee, Ju Young; Khim, Jeehyeong; Ji, Won Hyun

    2013-08-01

    The purpose of this study was to assess contaminated soil and groundwater for the urban redevelopment of a rapid transit railway and a new mega-shopping area. Contaminated soil and groundwater may interfere with the progress of this project, and residents and shoppers may be exposed to human health risks. The study area has been remediated after application of first remediation technologies. Of the entire area, several sites were still contaminated by waste materials and petroleum. For zinc (Zn) contamination, high Zn concentrations were detected because waste materials were disposed in the entire area. For petroleum contamination, high total petroleum hydrocarbon (TPH) and hydrocarbon degrading microbe concentrations were observed at the depth of 7 m because the underground petroleum storage tank had previously been located at this site. Correlation results suggest that TPH (soil) concentration is still related with TPH (groundwater) concentration. The relationship is taken into account in the Spearman coefficient (α).

  17. Characterization and Low-Cost Remediation of Soils Contaminated by Timbers in Community Gardens.

    PubMed

    Heiger-Bernays, W; Fraser, A; Burns, V; Diskin, K; Pierotti, D; Merchant-Borna, K; McClean, M; Brabander, D; Hynes, H P

    2009-01-01

    Urban community gardens worldwide provide significant health benefits to those gardening and consuming fresh produce from them. Urban gardens are most often placed in locations and on land in which soil contaminants reflect past practices and often contain elevated levels of metals and organic contaminants. Garden plot dividers made from either railroad ties or chromated copper arsenate (CCA) pressure treated lumber contribute to the soil contamination and provide a continuous source of contaminants. Elevated levels of polycyclic aromatic hydrocarbons (PAHs) derived from railroad ties and arsenic from CCA pressure treated lumber are present in the gardens studied. Using a representative garden, we 1) determined the nature and extent of urban community garden soil contaminated with PAHs and arsenic by garden timbers; 2) designed a remediation plan, based on our sampling results, with our community partner guided by public health criteria, local regulation, affordability, and replicability; 3) determined the safety and advisability of adding city compost to Boston community gardens as a soil amendment; and 4) made recommendations for community gardeners regarding healthful gardening practices. This is the first study of its kind that looks at contaminants other than lead in urban garden soil and that evaluates the effect on select soil contaminants of adding city compost to community garden soil.

  18. Cadmium accumulation and growth responses of a poplar (Populus deltoidsxPopulus nigra) in cadmium contaminated purple soil and alluvial soil.

    PubMed

    Wu, Fuzhong; Yang, Wanqin; Zhang, Jian; Zhou, Liqiang

    2010-05-15

    To characterize the phytoextraction efficiency of a hybrid poplar (Populus deltoidsxPopulus nigra) in cadmium contaminated purple soil and alluvial soil, a pot experiment in field was carried out in Sichuan basin, western China. After one growing period, the poplar accumulated the highest of 541.98+/-19.22 and 576.75+/-40.55 microg cadmium per plant with 110.77+/-12.68 and 202.54+/-19.12 g dry mass in these contaminated purple soil and alluvial soil, respectively. Higher phytoextraction efficiency with higher cadmium concentration in tissues was observed in poplar growing in purple soil than that in alluvial soil at relative lower soil cadmium concentration. The poplar growing in alluvial soil had relative higher tolerance ability with lower reduction rates of morphological and growth characters than that in purple soil, suggesting that the poplar growing in alluvial soil might display the higher phytoextraction ability when cadmium contamination level increased. Even so, the poplars exhibited obvious cadmium transport from root to shoot in both soils regardless of cadmium contamination levels. It implies that this examined poplar can extract more cadmium than some hyperaccumulators. The results indicated that metal phytoextraction using the poplar can be applied to clean up soils moderately contaminated by cadmium in these purple soil and alluvial soil. Copyright (c) 2009 Elsevier B.V. All rights reserved.

  19. Assessing the bioavailability and risk from metal-contaminated soils and dusts

    EPA Science Inventory

    Exposure to contaminated soil and dust is an important pathway in human health risk assessment. Physical and chemical characteristics, as well as biological factors, determine the bioaccessibility/bioavailability of soil and dust contaminants. Within a single sample, contaminat...

  20. Effect of Soil Aging on the Phytoremediation Potential of Zea mays in Chromium and Benzo[a]Pyrene Contaminated Soils.

    PubMed

    Chigbo, Chibuike

    2015-06-01

    This study compared the phytoremediation potential of Zea mays in soil either aged or freshly amended with chromium (Cr) and benzo[a]pyrene (B[a]P). Z. mays showed increased shoot biomass in aged soils than in freshly spiked soils. The shoot biomass in contaminated soils increased by over 50% in aged soil when compared to freshly amended soils, and over 29% more Cr was accumulated in the shoot of Z. mays in aged soil than in freshly amended soil. Planting Z. mays in aged soil helped in the dissipation of more than 31% B[a]P than in freshly spiked soil, but in the absence of plants, there seemed to be no difference between the dissipation rates of B[a]P in freshly and aged co-contaminated soil. Z. mays seemed to enhance the simultaneous removal of Cr and B[a]P in aged soil than in freshly spiked soil and hence can be a good plant choice for phytoremediation of co-contaminated soils.

  1. Microbially supported phytoremediation of heavy metal contaminated soils: strategies and applications.

    PubMed

    Phieler, René; Voit, Annekatrin; Kothe, Erika

    2014-01-01

    Heavy metal contamination of soil as a result of, for example, mining operations, evokes worldwide concern. The use of selected metal-accumulating plants to clean up heavy metal contaminated sites represents a sustainable and inexpensive method for remediation approaches and, at the same time, avoids destruction of soil function. Within this scenario, phytoremediation is the use of plants (directly or indirectly) to reduce the risks of contaminants in soil to the environment and human health. Microbially assisted bioremediation strategies, such as phytoextraction or phytostabilization, may increase the beneficial aspects and can be viewed as potentially useful methods for application in remediation of low and heterogeneously contaminated soil. The plant-microbe interactions in phytoremediation strategies include mutually beneficial symbiotic associations such as mycorrhiza, plant growth promoting bacteria (PGPB), or endophytic bacteria that are discussed with respect to their impact on phytoremediation approaches.

  2. Bioaugmentation of Soil Contaminated with Azoxystrobin.

    PubMed

    Baćmaga, Małgorzata; Wyszkowska, Jadwiga; Kucharski, Jan

    2017-01-01

    The presence of fungicides in the natural environment, either resulting from deliberate actions or not, has become a serious threat to many ecosystems, including soil. This can be prevented by taking appropriate measures to clear the environment of organic contamination, including fungicides. Therefore, a study was conducted aimed at determining the effect of bioaugmentation of soil exposed to azoxystrobin on its degradation and activity of selected enzymes (dehydrogenases, catalase, urease, acidic phosphatase, alkaline phosphatase). A model experiment was conducted for 90 days on two types of soil: loamy sand (pH KCl -5.6) and sandy loam (pH KCl -7.0), which were contaminated by azoxystrobin at 22.50 mg kg -1 DM of soil and inoculated with a specific consortium of microorganisms. Four strains of bacteria were used in the experiment ( Bacillus sp. LM655314.1, B. cereus KC848897.1, B. weihenstephanensis KF831381.1, B. megaterium KJ843149.1) and two strains of mould fungi ( Aphanoascus terreus AB861677.1, A. fulvescens JN943451.1). Inoculation of soil with the consortium of microorganisms accelerated the degradation of azoxystrobin. The isolated microorganisms were more active in loamy sand because within 90 days azoxystrobin was degraded by 24% ( Bacillus sp., B. cereus , B. weihenstephanensis , B. megaterium ) to 78% ( Aphanoascus terreus , A. fulvescens ). In sandy loam, azoxystrobin was degraded by 9% ( Aphanoascus terreus , A. fulvescens ) to 29% ( Bacillus sp., B. cereus , B. weihenstephanensis , B. megaterium and Aphanoascus terreus , A. fulvescens ). The activity of soil enzymes was also changed as a result of inoculation of soil with microorganisms. The activity of all of the enzymes under study was found to have increased when soil augmentation was performed.

  3. Eco-toxicity and metal contamination of paddy soil in an e-wastes recycling area.

    PubMed

    Jun-hui, Zhang; Hang, Min

    2009-06-15

    Paddy soil samples taken from different sites in an old primitive electronic-waste (e-waste) processing region were examined for eco-toxicity and metal contamination. Using the environmental quality standard for soils (China, Grade II) as reference, soil samples of two sites were weakly contaminated with trace metal, but site G was heavily contaminated with Cd (6.37 mg kg(-1)), and weakly contaminated with Cu (256.36 mg kg(-1)) and Zn (209.85 mg kg(-1)). Zn appeared to be strongly bound in the residual fraction (72.24-77.86%), no matter the soil was metal contaminated or not. However, more than 9% Cd and 16% Cu was present in the non-residual fraction in the metal contaminated soils than in the uncontaminated soil, especially for site G and site F. Compared with that of the control soil, the micronucleus rates of site G and site F soil treatments increased by 2.7-fold and 1.7-fold, respectively. Low germination rates were observed in site C (50%) and site G (50%) soil extraction treated rice seeds. The shortest root length (0.2377 cm) was observed in site G soil treated groups, which is only 37.57% of that of the control soil treated groups. All of the micronucleus ratio of Vicia faba root cells, rice germination rate and root length after treatment of soil extraction indicate the eco-toxicity in site F and G soils although the three indexes are different in sensitivity to soil metal contamination.

  4. Remediation of Nitrobenzene Contaminated Soil by Combining Surfactant Enhanced Soil Washing and Effluent Oxidation with Persulfate

    PubMed Central

    Yan, Jingchun; Gao, Weiguo; Qian, Linbo; Han, Lu; Chen, Yun; Chen, Mengfang

    2015-01-01

    The combination of surfactant enhanced soil washing and degradation of nitrobenzene (NB) in effluent with persulfate was investigated to remediate NB contaminated soil. Aqueous solution of sodium dodecylbenzenesulfonate (SDBS, 24.0 mmol L-1) was used at a given mass ratio of solution to soil (20:1) to extract NB contaminated soil (47.3 mg kg-1), resulting in NB desorption removal efficient of 76.8%. The washing effluent was treated in Fe2+/persulfate and Fe2+/H2O2 systems successively. The degradation removal of NB was 97.9%, being much higher than that of SDBS (51.6%) with addition of 40.0 mmol L-1 Fe2+ and 40.0 mmol L-1 persulfate after 15 min reaction. The preferential degradation was related to the lone pair electron of generated SO4•−, which preferably removes electrons from aromatic parts of NB over long alkyl chains of SDBS through hydrogen abstraction reactions. No preferential degradation was observed in •OH based oxidation because of its hydrogen abstraction or addition mechanism. The sustained SDBS could be reused for washing the contaminated soil. The combination of the effective surfactant-enhanced washing and the preferential degradation of NB with Fe2+/persulfate provide a useful option to remediate NB contaminated soil. PMID:26266532

  5. TNT transport and fate in contaminated soil

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Comfort, S.D.; Shea, P.J.; Hundal, L.S.

    1995-11-01

    Past disposal practices at munitions production plants have contaminated terrestrial and aquatk ecosystems with 2,4,6-trinitrotoluene (TNT). We determined TNT transport, degradation, and long-term sorption characteristics in soil. Transport experiments were conducted with repacked, unsaturated soil columns containing uncontaminated soil or layers of contaminated and uncontaminated soil. Uncontaminated soil columns received multiple pore volumes (22-50) of a TNT-{sup 3}H{sub 2}O pulse, containing 70 or 6.3 mg TNT L{sup -1} at a constant pore water velocity. TNT breakthrough curves (BTCs) never reached initial solute pulse concentrations. Apex concentrations (C/C{sub o}) were between 0.6 and 0.8 for an initial pulse of 70 mgmore » TNT L{sup -1} and 0.2 to 0.3 for the 6.3 mg TNT L{sup -1} pulse. Earlier TNT breakthrough was observed at the higher pulse concentration. This mobility difference was predicted from the nonlinear adsorption isotherm determined for TNT sorption. In all experiments, a significant fraction of added TNT was recovered as amino degradates of TNT. Mass balance estimates indicated 81% of the added TNT was recovered (as TNT and amino degradates) from columns receiving the 70 mg TNT L{sup -1} pulse compared to 35% from columns receiving the 6.3 mg TNT L{sup -1} pulse. Most of the unaccountable TNT was hypothesized to be unextractable. This was supported by a 168-d sorption experiment, which found that within 14d, 80% of {sup 14}C activity (added as {sup 14}C-TNT) was adsorbed and roughly 40% unextractable. Our observations illustrate that TNT sorption and degradation are concentration-dependent and the assumptions of linear adsorption and adsorption-desorption singularity commonly used in transport modeling, may not be valid for predicting TNT transport in munitions-contaminated soils. 29 refs., 6 figs., 7 tabs.« less

  6. Electrochemical EDTA recycling after soil washing of Pb, Zn and Cd contaminated soil.

    PubMed

    Pociecha, Maja; Kastelec, Damijana; Lestan, Domen

    2011-08-30

    Recycling of chelant decreases the cost of EDTA-based soil washing. Current methods, however, are not effective when the spent soil washing solution contains more than one contaminating metal. In this study, we applied electrochemical treatment of the washing solution obtained after EDTA extraction of Pb, Zn and Cd contaminated soil. A sacrificial Al anode and stainless steel cathode in a conventional electrolytic cell at pH 10 efficiently removed Pb from the solution. The method efficiency, specific electricity and Al consumption were significantly higher for solutions with a higher initial metal concentration. Partial replacement of NaCl with KNO(3) as an electrolyte (aggressive Cl(-) are required to prevent passivisation of the Al anode) prevented EDTA degradation during the electrolysis. The addition of FeCl(3) to the acidified washing solution prior to electrolysis improved Zn removal. Using the novel method 98, 73 and 66% of Pb, Zn and Cd, respectively, were removed, while 88% of EDTA was preserved in the treated washing solution. The recycled EDTA retained 86, 84 and 85% of Pb, Zn and Cd extraction potential from contaminated soil, respectively. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Remediation of arsenic-contaminated soils and groundwaters

    DOEpatents

    Peters, R.W.; Frank, J.R.; Feng, X.

    1998-06-23

    An in situ method is described for extraction of arsenic contaminants from a soil medium and remediation of the medium including contacting the medium with an extractant solution, directing the solution within and through the medium, and collecting the solution and contaminants. The method can also be used for arsenate and/or arsenite removal. 8 figs.

  8. Bioremediation of copper-contaminated soils by bacteria.

    PubMed

    Cornu, Jean-Yves; Huguenot, David; Jézéquel, Karine; Lollier, Marc; Lebeau, Thierry

    2017-02-01

    Although copper (Cu) is an essential micronutrient for all living organisms, it can be toxic at low concentrations. Its beneficial effects are therefore only observed for a narrow range of concentrations. Anthropogenic activities such as fungicide spraying and mining have resulted in the Cu contamination of environmental compartments (soil, water and sediment) at levels sometimes exceeding the toxicity threshold. This review focuses on the bioremediation of copper-contaminated soils. The mechanisms by which microorganisms, and in particular bacteria, can mobilize or immobilize Cu in soils are described and the corresponding bioremediation strategies-of varying levels of maturity-are addressed: (i) bioleaching as a process for the ex situ recovery of Cu from Cu-bearing solids, (ii) bioimmobilization to limit the in situ leaching of Cu into groundwater and (iii) bioaugmentation-assisted phytoextraction as an innovative process for in situ enhancement of Cu removal from soil. For each application, the specific conditions required to achieve the desired effect and the practical methods for control of the microbial processes were specified.

  9. Mercury uptake by Silene vulgaris grown on contaminated spiked soils.

    PubMed

    Pérez-Sanz, Araceli; Millán, Rocío; Sierra, M José; Alarcón, Remedios; García, Pilar; Gil-Díaz, Mar; Vazquez, Saúl; Lobo, M Carmen

    2012-03-01

    Mercury is a highly toxic pollutant with expensive clean up, because of its accumulative and persistent character in the biota. The objective of this work was to evaluate the effectiveness of Silene vulgaris, facultative metallophyte which have populations on both non-contaminated and metalliferous soils, to uptake Hg from artificially polluted soils. A pot experiment was carried out in a rain shelter for a full growth period. Two soils (C pH = 8.55 O.M. 0.63% and A pH = 7.07 O.M. 0.16%) were used, previously contaminated with Hg as HgCl(2) (0.6 and 5.5 mg Hg kg(-1) soil). Plants grew healthy and showed good appearance throughout the study without significantly decreasing biomass production. Mercury uptake by plants increased with the mercury concentration found in both soils. Differences were statistically significant between high dosage and untreated soil. The fact that S. vulgaris retains more mercury in root than in shoot and also, the well known effectiveness of these plants in the recovering of contaminated soils makes S. vulgaris a good candidate to phytostabilization technologies. Copyright © 2010 Elsevier Ltd. All rights reserved.

  10. Humic substances as a washing agent for Cd-contaminated soils.

    PubMed

    Meng, Fande; Yuan, Guodong; Wei, Jing; Bi, Dongxue; Ok, Yong Sik; Wang, Hailong

    2017-08-01

    Cost-effective and eco-friendly washing agents are in demand for Cd contaminated soils. Here, we used leonardite-derived humic substances to wash different types of Cd-contaminated soils, namely, a silty loam (Soil 1), a silty clay loam (Soil 2), and a sandy loam (Soil 3). Washing conditions were investigated for their effects on Cd removal efficiency. Cadmium removal was enhanced by a high humic substance concentration, long washing time, near neutral pH, and large solution/soil ratio. Based on the tradeoff between efficiency and cost, an optimum working condition was established as follows: humic substance concentration (3150 mg C/L), solution pH (6.0), washing time (2 h) and a washing solution/soil ratio (5). A single washing removed 0.55 mg Cd/kg from Soil 1 (1.33 mg Cd/kg), 2.32 mg Cd/kg from Soil 2 (6.57 mg Cd/kg), and 1.97 mg Cd/kg from Soil 3 (2.63 mg Cd/kg). Cd in effluents was effectively treated by adding a small dose of calcium hydroxide, reducing its concentration below the discharge limit of 0.1 mg/L in China. Being cost-effective and safe, humic substances have a great potential to replace common washing agents for the remediation of Cd-contaminated soils. Besides being environmentally benign, humic substances can improve soil physical, chemical, and biological properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. The effect of soil type on the bioremediation of petroleum contaminated soils.

    PubMed

    Haghollahi, Ali; Fazaelipoor, Mohammad Hassan; Schaffie, Mahin

    2016-09-15

    In this research the bioremediation of four different types of contaminated soils was monitored as a function of time and moisture content. The soils were categorized as sandy soil containing 100% sand (type I), clay soil containing more than 95% clay (type II), coarse grained soil containing 68% gravel and 32% sand (type III), and coarse grained with high clay content containing 40% gravel, 20% sand, and 40% clay (type IV). The initially clean soils were contaminated with gasoil to the concentration of 100 g/kg, and left on the floor for the evaporation of light hydrocarbons. A full factorial experimental design with soil type (four levels), and moisture content (10 and 20%) as the factors was employed. The soils were inoculated with petroleum degrading microorganisms. Soil samples were taken on days 90, 180, and 270, and the residual total petroleum hydrocarbon (TPH) was extracted using soxhlet apparatus. The moisture content of the soils was kept almost constant during the process by intermittent addition of water. The results showed that the efficiency of bioremediation was affected significantly by the soil type (Pvalue < 0.05). The removal percentage was the highest (70%) for the sandy soil with the initial TPH content of 69.62 g/kg, and the lowest for the clay soil (23.5%) with the initial TPH content of 69.70 g/kg. The effect of moisture content on bioremediation was not statistically significant for the investigated levels. The removal percentage in the clay soil was improved to 57% (within a month) in a separate experiment by more frequent mixing of the soil, indicating low availability of oxygen as a reason for low degradation of hydrocarbons in the clay soil. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Soil pollution in the railway junction Niš (Serbia) and possibility of bioremediation of hydrocarbon-contaminated soil

    NASA Astrophysics Data System (ADS)

    Jovanovic, Larisa; Aleksic, Gorica; Radosavljevic, Milan; Onjia, Antonije

    2015-04-01

    Mineral oil leaking from vehicles or released during accidents is an important source of soil and ground water pollution. In the railway junction Niš (Serbia) total 90 soil samples polluted with mineral oil derivatives were investigated. Field work at the railway Niš sites included the opening of soil profiles and soil sampling. The aim of this work is the determination of petroleum hydrocarbons concentration in the soil samples and the investigation of the bioremediation technique for treatment heavily contaminated soil. For determination of petroleum hydrocarbons in the soil samples method of gas-chromatography was carried out. On the basis of measured concentrations of petroleum hydrocarbons in the soil it can be concluded that: Obtained concentrations of petroleum hydrocarbons in 60% of soil samples exceed the permissible values (5000 mg/kg). The heavily contaminated soils, according the Regulation on the program of systematic monitoring of soil quality indicators for assessing the risk of soil degradation and methodology for development of remediation programs, Annex 3 (Official Gazette of RS, No.88 / 2010), must be treated using some of remediation technologies. Between many types of phytoremediation of soil contaminated with mineral oils and their derivatives, the most suitable are phytovolatalisation and phytostimulation. During phytovolatalisation plants (poplar, willow, aspen, sorgum, and rye) absorb organic pollutants through the root, and then transported them to the leaves where the reduced pollutants are released into the atmosphere. In the case of phytostimulation plants (mulberry, apple, rye, Bermuda) secrete from the roots enzymes that stimulates the growth of bacteria in the soil. The increase in microbial activity in soil promotes the degradation of pollutants. Bioremediation is performed by composting the contaminated soil with addition of composting materials (straw, manure, sawdust, and shavings), moisture components, oligotrophs and

  13. Speciation and leaching of trace metal contaminants from e-waste contaminated soils.

    PubMed

    Cui, Jin-Li; Luo, Chun-Ling; Tang, Chloe Wing-Yee; Chan, Ting-Shan; Li, Xiang-Dong

    2017-05-05

    Primitive electrical and electronic waste (e-waste) recycling activities have caused serious environmental problems. However, little is known about the speciation and leaching behaviors of metal contaminants at e-waste contaminated sites. This study investigated trace metal speciation/mobilization from e-waste polluted soil through column leaching experiments involving irrigation with rainwater for almost 2.5 years. Over the experimental period, Cu and Zn levels in the porewater were 0.14±0.08mg/L, and 0.16±0.08mg/L, respectively, increasing to 0.33±0.16mg/L, and 0.69±0.28mg/L with plant growth. The amounts of Cu, Zn, and Pb released in surface soil (0-2cm) contributed 43.8%, 22.5%, and 13.8%, respectively, to the original levels. The released Cu and Zn were primarily caused by the mobilization of the carbonate species of metals, including Cu(OH) 2 , CuCO 3 , and Zn 5 (CO 3 ) 2 (OH) 6 , and amorphous Fe/Mn oxides associated fractions characterized by sequential extraction coupling with X-ray absorption spectroscopy. During the experiments, trace metals were not detected in the effluent, and the re-sequestration of trace metals was mainly attributed to the adsorption on the abundant Fe/Mn oxides in the sub-layer soil. This study quantitatively elucidated the molecular speciation of Cu and Zn in e-waste contaminated soil during the column leaching process. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Pilot scale aided-phytoremediation of a co-contaminated soil.

    PubMed

    Marchand, Charlotte; Mench, Michel; Jani, Yahya; Kaczala, Fabio; Notini, Peter; Hijri, Mohamed; Hogland, William

    2018-03-15

    A pilot scale experiment was conducted to investigate the aided-phytoextraction of metals and the aided-phytodegradation of petroleum hydrocarbons (PHC) in a co-contaminated soil. First, this soil was amended with compost (10% w/w) and assembled into piles (Unp-10%C). Then, a phyto-cap of Medicago sativa L. either in monoculture (MS-10%C) or co-cropped with Helianthus annuus L. as companion planting (MSHA-10%C) was sown on the topsoil. Physico-chemical parameters and contaminants in the soil and its leachates were measured at the beginning and the end of the first growth season (after five months). In parallel, residual soil ecotoxicity was assessed using the plant species Lepidium sativum L. and the earthworm Eisenia fetida Savigny, 1826, while the leachate ecotoxicity was assessed using Lemna minor L. After 5months, PH C10-C40, PAH-L, PAH-M PAH-H, Pb and Cu concentrations in the MS-10%C soil were significantly reduced as compared to the Unp-10%C soil. Metal uptake by alfalfa was low but their translocation to shoots was high for Mn, Cr, Co and Zn (transfer factor (TF) >1), except for Cu and Pb. Alfalfa in monoculture reduced electrical conductivity, total organic C and Cu concentration in the leachate while pH and dissolved oxygen increased. Alfalfa co-planting with sunflower did not affect the extraction of inorganic contaminants from the soil, the PAH (M and H) degradation and was less efficient for PH C10-C40 and PAH-L as compared to alfalfa monoculture. The co-planting reduced shoot and root Pb concentrations. The residual soil ecotoxicity after 5months showed a positive effect of co-planting on L. sativum shoot dry weight (DW) yield. However, high contaminant concentrations in soil and leachate still inhibited the L. sativum root DW yield, earthworm development, and L. minor growth rate. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Chelant extraction of heavy metals from contaminated soils.

    PubMed

    Peters, R W

    1999-04-23

    The current state of the art regarding the use of chelating agents to extract heavy metal contaminants has been addressed. Results are presented for treatability studies conducted as worst-case and representative soils from Aberdeen Proving Ground's J-Field for extraction of copper (Cu), lead (Pb), and zinc (Zn). The particle size distribution characteristics of the soils determined from hydrometer tests are approximately 60% sand, 30% silt, and 10% clay. Sequential extractions were performed on the 'as-received' soils (worst case and representative) to determine the speciation of the metal forms. The technique speciates the heavy metal distribution into an easily extractable (exchangeable) form, carbonates, reducible oxides, organically-bound, and residual forms. The results indicated that most of the metals are in forms that are amenable to soil washing (i.e. exchangeable+carbonate+reducible oxides). The metals Cu, Pb, Zn, and Cr have greater than 70% of their distribution in forms amenable to soil washing techniques, while Cd, Mn, and Fe are somewhat less amenable to soil washing using chelant extraction. However, the concentrations of Cd and Mn are low in the contaminated soil. From the batch chelant extraction studies, ethylenediaminetetraacetic acid (EDTA), citric acid, and nitrilotriacetic acid (NTA) were all effective in removing copper, lead, and zinc from the J-Field soils. Due to NTA being a Class II carcinogen, it is not recommended for use in remediating contaminated soils. EDTA and citric acid appear to offer the greatest potential as chelating agents to use in soil washing the Aberdeen Proving Ground soils. The other chelating agents studied (gluconate, oxalate, Citranox, ammonium acetate, and phosphoric acid, along with pH-adjusted water) were generally ineffective in mobilizing the heavy metals from the soils. The chelant solution removes the heavy metals (Cd, Cu, Pb, Zn, Fe, Cr, As, and Hg) simultaneously. Using a multiple-stage batch extraction

  16. Predicting arsenic bioavailability to hyperaccumulator Pteris vittata in arsenic-contaminated soils.

    PubMed

    Gonzaga, Maria Isidória Silva; Ma, Lena Q; Pacheco, Edson Patto; dos Santos, Wallace Melo

    2012-12-01

    Using chemical extraction to evaluate plant arsenic availability in contaminated soils is important to estimate the time frame for site cleanup during phytoremediation. It is also of great value to assess As mobility in soil and its risk in environmental contamination. In this study, four conventional chemical extraction methods (water, ammonium sulfate, ammonium phosphate, and Mehlich III) and a new root-exudate based method were used to evaluate As extractability and to correlate it with As accumulation in P. vittata growing in five As-contaminated soils under greenhouse condition. The relationship between different soil properties, and As extractability and plant As accumulation was also investigated. Arsenic extractability was 4.6%, 7.0%, 18%, 21%, and 46% for water, ammonium sulfate, organic acids, ammonium phosphate, and Mehlich III, respectively. Root exudate (organic acids) solution was suitable for assessing As bioavailability (81%) in the soils while Mehlich III (31%) overestimated the amount of As taken up by plants. Soil organic matter, P and Mg concentrations were positively correlated to plant As accumulation whereas Ca concentration was negatively correlated. Further investigation is needed on the effect of Ca and Mg on As uptake by P. vittata. Moreover, additional As contaminated soils with different properties should be tested.

  17. PHYTOREMEDIATION OF SOILS CONTAMINATED WITH WOOD PRESERVATIVES: GREENHOUSE AND FIELD EVALUATIONS

    EPA Science Inventory

    Phytoremediation was evaluated as a potential treatment for the creosote-contaminated surface soil at the McCormick and Baxter (M&B) Superfund Site in Portland, OR. Soil a the M&B site is contaminated with pentachlorophenol (PCP) and polyaromatic hydrocarbons (PAHs). Eight indivi...

  18. Effect of long-term zinc pollution on soil microbial community resistance to repeated contamination.

    PubMed

    Klimek, Beata

    2012-04-01

    The aim of the study was to compare the effects of stress (contamination trials) on the microorganisms in zinc-polluted soil (5,018 mg Zn kg(-1) soil dry weight) and unpolluted soil (141 mg Zn kg(-1) soil dw), measured as soil respiration rate. In the laboratory, soils were subjected to copper contamination (0, 500, 1,500 and 4,500 mg kg(-1) soil dw), and then a bactericide (oxytetracycline) combined with a fungicide (captan) along with glucose (10 mg g(-1) soil dw each) were added. There was a highly significant effect of soil type, copper treatment and oxytetracycline/captan treatment. The initial respiration rate of chronically zinc-polluted soil was higher than that of unpolluted soil, but in the copper treatment it showed a greater decline. Microorganisms in copper-treated soil were more susceptible to oxytetracycline/captan contamination. After the successive soil contamination trials the decline of soil respiration was greater in zinc-polluted soil than in unpolluted soil.

  19. Phytostabilization potential of ornamental plants grown in soil contaminated with cadmium.

    PubMed

    Zeng, Peng; Guo, Zhaohui; Cao, Xia; Xiao, Xiyuan; Liu, Yanan; Shi, Lei

    2018-03-21

    In a greenhouse experiment, five ornamental plants, Osmanthus fragrans (OF), Ligustrum vicaryi L. (LV), Cinnamomum camphora (CC), Loropetalum chinense var. rubrum (LC), and Euonymus japonicas cv. Aureo-mar (EJ), were studied for the ability to phytostabilization for Cd-contaminated soil. The results showed that these five ornamental plants can grow normally when the soil Cd content is less than 24.6 mg·kg -1 . Cd was mainly deposited in the roots of OF, LV, LC and EJ which have grown in Cd-contaminated soils, and the maximum Cd contents reached 15.76, 19.09, 20.59 and 32.91 mg·kg -1 , respectively. For CC, Cd was mainly distributed in the shoots and the maximum Cd content in stems and leaves were 12.5 and 10.71 mg·kg -1 , however, the total amount of Cd in stems and leaves was similar with the other ornamental plants. The enzymatic activities in Cd-contaminated soil were benefited from the five tested ornamental plants remediation. Soil urease and sucrase activities were improved, while dehydrogenase activity was depressed. Meanwhile, the soil microbial community was slightly influenced when soil Cd content is less than 24.6 mg·kg -1 under five ornamental plants remediation. The results further suggested that ornamental plants could be promising candidates for phytostabilization of Cd-contaminated soil.

  20. Application and validation of isotope dilution method (IDM) for predicting bioavailability of hydrophobic organic contaminants in soil.

    PubMed

    Wang, Jie; Taylor, Allison; Schlenk, Daniel; Gan, Jay

    2018-05-01

    Risk assessment of hydrophobic organic contaminants (HOCs) using the total chemical concentration following exhaustive extraction may overestimate the actual availability of HOCs to non-target organisms. Existing methods for estimating HOC bioavailability in soil have various operational limitations. In this study, we explored the application of isotope dilution method (IDM) to quantify the accessible fraction (E) of DDTs and PCBs in both historically-contaminated and freshly-spiked soils. After addition of 13 C or deuterated analogues to a soil sample, the phase distribution of isotope-labeled and native chemicals reached an apparent equilibrium within 48 h of mixing. The derived E values in the three soils ranged from 0.19 to 0.82, depending on the soil properties and also the contact time of HOCs (i.e., aging). The isotope dilution method consistently predicted greater accumulation into earthworm (Eisenia fetida) than that by polyethylene (PE) or solid phase microextraction (SPME) sampler, likely because desorption in the gut enhanced bioavailability of soil-borne HOCs. A highly significant linear regression (R 2  = 0.91) was found between IDM and 24-h Tenax desorption, with a slope statistically identical to 1. The IDM-derived accessible concentration (C e ) was further shown to accurately predict tissue residues in earthworm exposed in the same soils. Given the relatively short duration and simple steps, IDM has the potential to be readily adopted for measuring HOC bioaccessibility in soil and for improving risk assessment and evaluation of remediation efficiency. Copyright © 2018 Elsevier Ltd. All rights reserved.

  1. Copper removal from contaminated soils by soil washing process using camellian-derived saponin

    NASA Astrophysics Data System (ADS)

    Reyes, Arturo; Fernanda Campos, Maria; Videla, Álvaro; Letelier, María Victoria; Fuentes, Bárbara

    2015-04-01

    Antofagasta Region in North of Chile has been the main copper producer district in the world. As a consequence of a lack of mining closure regulation, a large number of abandon small-to-medium size metal-contaminated sites have been identified in the last survey performed by the Chilean Government. Therefore, more research development on sustainable reclamation technologies must be made in this extreme arid-dry zone. The objective of this study is to test the effectiveness of soil remediation by washing contaminated soil using camellian-derived saponin for the mobilization of copper. Soil samples were taken from an abandoned copper mine site located at 30 km North Antofagasta city. They were dried and sieved at 75 µm for physico-chemical characterization. A commercial saponin extracted from camellias seed was used as biosurfactant. The soil used contains 67.4 % sand, 26.3 % silt and 6.3 % clay. The soil is highly saline (electric conductivity, 61 mScm-1), with low organic matter content (0.41%), with pH 7.30, and a high copper concentration (2200 mg Kg-1 soil). According to the sequential extraction procedure of the whole soil, copper species are mainly as exchangeable fraction (608.2 mg Kg-1 soil) and reducible fraction (787.3 mg Kg-1 soil), whereas the oxidizable and residual fractions are around 205.7 and 598.8 mg Kg-1 soil, respectively. Soil particles under 75 µm contain higher copper concentrations (1242 mg Kg-1 soil) than the particle fraction over 75 µm (912 mg Kg-1 soil). All washing assays were conducted in triplicate using a standard batch technique with and without pH adjustment. The testing protocols includes evaluation of four solid to liquid ratio (0.5:50; 1.0:50; 2.0:50, and 5.0:50) and three saponin concentrations (0, 1, and 4 mg L-1). After shaking (24 h, 20±1 °C) and subsequently filtration (0.45 µm), the supernatants were analyzed for copper and pH. The removal efficiencies of copper by saponin solutions were calculated in according to the

  2. Immobilization of uranium in contaminated soil by natural apatite addition

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mrdakovic Popic, Jelena; Stojanovic, Mirjana; Milosevic, Sinisa

    2007-07-01

    Available in abstract form only. Full text of publication follows: The goal of this study was to evaluate the effectiveness of Serbian natural mineral apatite as soil additive for reducing the migration of uranium from contaminated sediments. In laboratory study we investigated the sorption properties of domestic apatite upon different experimental conditions, such as pH, adsorbent mass, reaction period, concentration of P{sub 2}O{sub 5} in apatite, solid/liquid ratio. In second part of study, we did the quantification of uranium in soil samples, taken from uranium mine site 'Kalna', by sequential extraction method. The same procedure was, also, used for uraniummore » determination in contaminated soil samples after apatite addition, in order to determine the changes in U distribution in soil fraction. The obtained results showed the significant level of immobilization (96.7%) upon certain conditions. Increase of %P{sub 2}O{sub 5} in apatite and process of mechano-chemical activation led to increase of immobilization capacity from 17.50% till 91.64%. The best results for uranium binding were obtained at pH 5.5 and reaction period 60 days (98.04%) The sequential extraction showed the presence of uranium (48.2%) in potentially available soil fractions, but with the apatite addition uranium content in these fractions decreased (30.64%), what is considering environmental aspect significant fact. In situ immobilization of radionuclide using inexpensive sequestering agents, such as apatite, is very adequate for big contaminated areas of soil with low level of contamination. This investigation study on natural apatite from deposit 'Lisina' Serbia was the first one of this type in our country. Key words: apatite, uranium, immobilization, soil, contamination. (authors)« less

  3. Decontamination of Soil Contaminated with Bacillus anthracis ...

    EPA Pesticide Factsheets

    Technical Brief This technical summary will provide decontamination personnel rapid access to information on which decontamination approaches are most effective for soils contaminated with B anthracis.

  4. ENGINEERING BULLETIN: SEPARATION/CONCENTRATION TECHNOLOGY ALTERNATIVES FOR THE REMEDIATION OF PESTICIDE-CONTAMINATED SOIL

    EPA Science Inventory

    Pesticide contamination includes a wide variety of compounds and may result from manufacturing improper storage, handling, disposal; or agricultural processes. It can occur in soil and can lead to secondary contamination of groundwater. Remediation of pesticide-contaminated soils...

  5. Sea Level Rise Induced Arsenic Release from Historically Contaminated Coastal Soils.

    PubMed

    LeMonte, Joshua J; Stuckey, Jason W; Sanchez, Joshua Z; Tappero, Ryan; Rinklebe, Jörg; Sparks, Donald L

    2017-06-06

    Climate change-induced perturbations in the hydrologic regime are expected to impact biogeochemical processes, including contaminant mobility and cycling. Elevated levels of geogenic and anthropogenic arsenic are found along many coasts around the world, most notably in south and southeast Asia but also in the United States, particularly along the Mid-Atlantic coast. The mechanism by and the extent to which arsenic may be released in contaminated coastal soils due to sea level rise are unknown. Here we show a series of data from a coastal arsenic-contaminated soil exposed to sea and river waters in biogeochemical microcosm reactors across field-validated redox conditions. We find that reducing conditions lead to arsenic release from historically contaminated coastal soils through reductive dissolution of arsenic-bearing mineral oxides in both sea and river water inundations, with less arsenic release from seawater scenarios than river water due to inhibition of oxide dissolution. For the first time, we systematically display gradation of solid phase soil-arsenic speciation across defined redox windows from reducing to oxidizing conditions in natural waters by combining biogeochemical microcosm experiments and X-ray absorption spectroscopy. Our results demonstrate the threat of sea level rise stands to impact arsenic release from contaminated coastal soils by changing redox conditions.

  6. Sea Level Rise Induced Arsenic Release from Historically Contaminated Coastal Soils

    DOE PAGES

    LeMonte, Joshua J.; Stuckey, Jason W.; Sanchez, Joshua Z.; ...

    2017-05-04

    Climate change-induced perturbations in the hydrologic regime are expected to impact biogeochemical processes, including contaminant mobility and cycling. Elevated levels of geogenic and anthropogenic arsenic are found along many coasts around the world, most notably in south and southeast Asia but also in the United States, particularly along the Mid-Atlantic coast. The mechanism by and the extent to which arsenic may be released in contaminated coastal soils due to sea level rise are unknown. Here we show a series of data from a coastal arsenic-contaminated soil exposed to sea and river waters in biogeochemical microcosm reactors across field-validated redox conditions.more » We find that reducing conditions lead to arsenic release from historically contaminated coastal soils through reductive dissolution of arsenic-bearing mineral oxides in both sea and river water inundations, with less arsenic release from seawater scenarios than river water due to inhibition of oxide dissolution. For the first time, we systematically display gradation of solid phase soil-arsenic speciation across defined redox windows from reducing to oxidizing conditions in natural waters by combining biogeochemical microcosm experiments and X-ray absorption spectroscopy. Here, our results demonstrate the threat of sea level rise stands to impact arsenic release from contaminated coastal soils by changing redox conditions.« less

  7. Sea Level Rise Induced Arsenic Release from Historically Contaminated Coastal Soils

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    LeMonte, Joshua J.; Stuckey, Jason W.; Sanchez, Joshua Z.

    Climate change-induced perturbations in the hydrologic regime are expected to impact biogeochemical processes, including contaminant mobility and cycling. Elevated levels of geogenic and anthropogenic arsenic are found along many coasts around the world, most notably in south and southeast Asia but also in the United States, particularly along the Mid-Atlantic coast. The mechanism by and the extent to which arsenic may be released in contaminated coastal soils due to sea level rise are unknown. Here we show a series of data from a coastal arsenic-contaminated soil exposed to sea and river waters in biogeochemical microcosm reactors across field-validated redox conditions.more » We find that reducing conditions lead to arsenic release from historically contaminated coastal soils through reductive dissolution of arsenic-bearing mineral oxides in both sea and river water inundations, with less arsenic release from seawater scenarios than river water due to inhibition of oxide dissolution. For the first time, we systematically display gradation of solid phase soil-arsenic speciation across defined redox windows from reducing to oxidizing conditions in natural waters by combining biogeochemical microcosm experiments and X-ray absorption spectroscopy. Here, our results demonstrate the threat of sea level rise stands to impact arsenic release from contaminated coastal soils by changing redox conditions.« less

  8. Bioavailability and mobility of organic contaminants in soil: new three-step ecotoxicological evaluation.

    PubMed

    Prokop, Zbyněk; Nečasová, Anežka; Klánová, Jana; Čupr, Pavel

    2016-03-01

    A novel approach was developed for rapid assessment of bioavailability and potential mobility of contaminants in soil. The response of the same test organism to the organic extract, water extract and solid phase of soil was recorded and compared. This approach was designed to give an initial estimate of the total organic toxicity (response to organic extractable fraction), as well as the mobile (response to water extract) and bioavailable fraction (response to solid phase) of soil samples. Eighteen soil samples with different levels of pollution and content of organic carbon were selected to validate the novel three-step ecotoxicological evaluation approach. All samples were chemically analysed for priority contaminants, including aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), hexachlorocyclohexane (HCH) and dichlordiphenyltrichloroethane (DDT). The ecotoxicological evaluation involved determination of toxicity of the organic, mobile and bioavailable fractions of soil to the test organism, bacterium Bacillus cereus. We found a good correlation between the chemical analysis and the toxicity of organic extract. The low toxicity of water extracts indicated low water solubility, and thus, low potential mobility of toxic contaminants present in the soil samples. The toxicity of the bioavailable fraction was significantly greater than the toxicity of water-soluble (mobile) fraction of the contaminants as deduced from comparing untreated samples and water extracts. The bioavailability of the contaminants decreased with increasing concentrations of organic carbon in evaluated soil samples. In conclusion, the three-step ecotoxicological evaluation utilised in this study can give a quick insight into soil contamination in context with bioavailability and mobility of the contaminants present. This information can be useful for hazard identification and risk assessment of soil-associated contaminants. Graphical Abstract New three-step ecotoxicological

  9. Remediation of lead and cadmium-contaminated soils.

    PubMed

    Salama, Ahmed K; Osman, Khaled A; Gouda, Neama Abdel-Razeek

    2016-01-01

    The research was designated to study the ability of plants to bio-accumulate, translocate and remove the heavy metals, lead and cadmium from contaminated soil. The herbal plant ryegrass, Lolium multiflorum was investigated as a bio-accumulator plant for these metals. The translocation of these heavy metals in the herbal plant was compared considering root to shoot transport and redistribution of metals in the root and shoot system. The trace metal contents from root and shoot parts were determined using atomic absorption spectrometer. The results showed that the percent of lead and cadmium transferred to ryegrass plant were averaged as 51.39, and 74.57%, respectively, while those remained in the soil were averaged as 48.61 and 25.43% following 60 days of treatment. The soil-plant transfer index in root and shoot system of ryegrass was found to be 0.32 and 0.20 for lead, and 0.50 and 0.25 for cadmium. These findings indicated that the herbal plant ryegrass, Lolium multiflorum is a good accumulator for cadmium than lead. The soil-plant transfer factor (the conc. of heavy metal in plant to the conc. in soil) indicated that the mechanism of soil remedy using the investigated plant is phytoextraction where the amounts of heavy metals transferred by plant roots into the above ground portions were higher than that remained in the soil. The method offers green technology solution for the contamination problem since it is effective technology with minimal impact on the environment and can be easily used for soil remedy.

  10. Effect of an alkaline environment on the engineering behavior of cement-stabilized/solidified Zn-contaminated soils.

    PubMed

    Liu, Jingjing; Zha, Fusheng; Deng, Yongfeng; Cui, Kerui; Zhang, Xueqin

    2017-12-01

    Although the stabilization/solidification method has been widely used for remediation of heavy metal-contaminated soils in recent decades, the engineering behavior and mobility of heavy metal ions under alkaline groundwater conditions are still unclear. Therefore, the unconfined compressive strength test (UCS) combined with toxicity characteristic leaching procedure (TCLP) and general acid neutralization capacity (GANC) was used to investigate the effects of alkalinity (using NaOH to simulate alkalinity in the environment) on the mechanical and leaching characteristics of cement-solidified/stabilized (S/S) Zn-contaminated soils. Moreover, the microstructure was analyzed using the scanning electron microscope (SEM) technology. The results indicated that alkaline environment could accelerate the UCS development compared with specimens without soaking in NaOH solution,, regardless of whether the specimens contained Zn 2+ or not. And the UCS varied obviously attributed to the variations of both NaOH concentration and soaking time. Except for the specimens soaked for 90 days, the leached Zn 2+ concentrations were higher than that of without soaking. However, the leachability of Zn 2+ in all the stabilized specimens is in the regulatory level. ANC results indicated that the Zn 2+ leaching behavior can be divided into three stages related to the initial leachate pH. Moreover, SEM results proved that the alkaline environment could actually facilitate the cement hydration process. The results proved in the present paper could be useful in treating the heavy metal-contaminated soils involved in the solidification/stabilization technology under alkaline environment.

  11. Bioremediation of creosote-contaminated soil in South Africa by landfarming.

    PubMed

    Atagana, H I

    2004-01-01

    To determine the combined effects of biostimulation and bioaugmentation in the landfarming of a mispah form (lithosol; food and Agriculture Organisation (FAO)) soil contaminated with >310000 mg kg-1 creosote with a view to developing a bioremediation technology for soils heavily contaminated with creosote. The excavated soil was mixed with 2500 kg ha-1 dolomitic lime and 2000 kg ha-1 mono-ammonium phosphate (MAP) before spreading over a treatment bed of shale reinforced with clay. Sewage sludge (500 kg) was ploughed into 450 m3 of contaminated soil in the second and sixth months of treatment. A further 1000 kg ha-1 MAP was added to the soil at the end of the fifth month. Moisture was maintained at 70% field capacity. Total creosote was determined by the US Environmental Protection Agency (EPA) method 418.1 and concentrations of selected creosote components were determined by gas chromatography/flame ionisation detection (GC/FID). Total creosote was reduced by more than 90% by the 10th month of landfarming. The rate of reduction in creosote concentration was highest after the addition of sewage sludge. The three-ring PAHs were more slowly removed than naphthalene and the phenolic compounds. The four- and five-ring PAHs, although persist until the end of treatment, were reduced by 76-87% at the end of the experiment. A combination of biostimulation and bioaugmentation during landfarming could enhance the bioremediation of soils heavily contaminated with creosote. The study provides information on the management of a combination of biostimulation and bioaugmentation during landfarming, and contributes to the knowledge and database necessary for the development of a technology for bioremediating creosote-contaminated land.

  12. Immobilization of Lead Migrating from Contaminated Soil in Rhizosphere Soil of Barley (Hordeum vulgare L.) and Hairy Vetch (Vicia villosa) Using Hydroxyapatite.

    PubMed

    Katoh, Masahiko; Risky, Elsya; Sato, Takeshi

    2017-10-23

    This study conducted plant growth tests using a rhizobox system to quantitatively determine the distance of immobilization lead migrating from contaminated soil into uncontaminated rhizosphere soil, and to assess the lead phases accumulated in rhizosphere soil by sequential extraction. Without the hydroxyapatite, exchangeable lead fractions increased as the rhizosphere soil got closer to the contaminated soil. Exchangeable lead fractions were higher even in the rhizosphere soil that shares a boundary with the root surface than in the soil before being planted. Thus, plant growth of hairy vetch was lower in the soil without the hydroxyapatite than in the soil with the hydroxyapatite. The presence of hydroxyapatite may immobilize the majority of lead migrating from contaminated soil into the rhizosphere soil within 1 mm from the contaminated soil. The dominant lead fraction in the rhizosphere soil with the hydroxyapatite was residual. Thus, plant growth was not suppressed and the lead concentration of the plant shoot remained at the background level. These results indicate that the presence of hydroxyapatite in the rhizosphere soil at 5% wt may immobilize most of the lead migrating into the rhizosphere soil within 1 mm from the contaminated soil, resulting in the prevention of lead migration toward the root surface.

  13. Immobilization of Lead Migrating from Contaminated Soil in Rhizosphere Soil of Barley (Hordeum vulgare L.) and Hairy Vetch (Vicia villosa) Using Hydroxyapatite

    PubMed Central

    Risky, Elsya; Sato, Takeshi

    2017-01-01

    This study conducted plant growth tests using a rhizobox system to quantitatively determine the distance of immobilization lead migrating from contaminated soil into uncontaminated rhizosphere soil, and to assess the lead phases accumulated in rhizosphere soil by sequential extraction. Without the hydroxyapatite, exchangeable lead fractions increased as the rhizosphere soil got closer to the contaminated soil. Exchangeable lead fractions were higher even in the rhizosphere soil that shares a boundary with the root surface than in the soil before being planted. Thus, plant growth of hairy vetch was lower in the soil without the hydroxyapatite than in the soil with the hydroxyapatite. The presence of hydroxyapatite may immobilize the majority of lead migrating from contaminated soil into the rhizosphere soil within 1 mm from the contaminated soil. The dominant lead fraction in the rhizosphere soil with the hydroxyapatite was residual. Thus, plant growth was not suppressed and the lead concentration of the plant shoot remained at the background level. These results indicate that the presence of hydroxyapatite in the rhizosphere soil at 5% wt may immobilize most of the lead migrating into the rhizosphere soil within 1 mm from the contaminated soil, resulting in the prevention of lead migration toward the root surface. PMID:29065529

  14. Bioremediation of a weathered and a recently oil-contaminated soils from Brazil: a comparison study.

    PubMed

    Trindade, P V O; Sobral, L G; Rizzo, A C L; Leite, S G F; Soriano, A U

    2005-01-01

    The facility with which hydrocarbons can be removed from soils varies inversely with aging of soil samples as a result of weathering. Weathering refers to the result of biological, chemical and physical processes that can affect the type of hydrocarbons that remain in a soil. These processes enhance the sorption of hydrophobic organic contaminants (HOCs) to the soil matrix, decreasing the rate and extent of biodegradation. Additionally, pollutant compounds in high concentrations can more easily affect the microbial population of a recently contaminated soil than in a weathered one, leading to inhibition of the biodegradation process. The present work aimed at comparing the biodegradation efficiencies obtained in a recently oil-contaminated soil (spiked one) from Brazil and an weathered one, contaminated for four years, after the application of bioaugmentation and biostimulation techniques. Both soils were contaminated with 5.4% of total petroleum hydrocarbons (TPHs) and the highest biodegradation efficiency (7.4%) was reached for the weathered contaminated soil. It could be concluded that the low biodegradation efficiencies reached for all conditions tested reflect the treatment difficulty of a weathered soil contaminated with a high crude oil concentration. Moreover, both soils (weathered and recently contaminated) submitted to bioaugmentation and biostimulation techniques presented biodegradation efficiencies approximately twice as higher as the ones without the aforementioned treatment (natural attenuation).

  15. Assessing the external benefits of contaminated soil remediation in Korea: a choice experiment study.

    PubMed

    Lim, Seul-Ye; Kim, Hyo-Jin; Yoo, Seung-Hoon

    2018-06-01

    Korean government has made and will continue to make a considerable investment in contaminated soil remediation to rectify the problems that arise from soil pollution. Quantitative information on the benefits of contaminated soil remediation is widely demanded by the public as well as the government. This article aims to assess the external benefits of contaminated soil remediation. A survey of 1000 randomly selected households was undertaken in Korea. The results show that the marginal willingness to pay values for a 1% decrease in human health hazard, a 1% improvement in biodiversity restoration, and 1000 new job creation by contaminated soil remediation are estimated to be KRW 204 (USD 0.17), 593 (0.50), and 238 (0.20) per household per year. The findings can provide policy-makers with useful information for both evaluating and planning the contaminated soil remediation.

  16. Remediation of multiple heavy metal-contaminated soil through the combination of soil washing and in situ immobilization.

    PubMed

    Zhai, Xiuqing; Li, Zhongwu; Huang, Bin; Luo, Ninglin; Huang, Mei; Zhang, Qiu; Zeng, Guangming

    2018-09-01

    The remediation of heavy metal-contaminated soils is a great challenge for global environmental sciences and engineering. To control the ecological risks of heavy metal-contaminated soil more effectively, the present study focused on the combination of soil washing (with FeCl 3 ) and in situ immobilization (with lime, biochar, and black carbon). The results showed that the removal rate of Cd, Pb, Zn, and Cu was 62.9%, 52.1%, 30.0%, and 16.7%, respectively, when washed with FeCl 3 . After the combined remediation (immobilization with 1% (w/w) lime), the contaminated soils showed 36.5%, 73.6%, 70.9%, and 53.4% reductions in the bioavailability of Cd, Cu, Pb, and Zn (extracted with 0.11M acetic acid), respectively, than those of the soils washed with FeCl 3 only. However, the immobilization with 1% (w/w) biochar or 1% (w/w) carbon black after washing exhibited low effects on stabilizing the metals. The differences in effects between the immobilization with lime, biochar, and carbon black indicated that the soil pH had a significant influence on the lability of heavy metals during the combined remediation process. The activity of the soil enzymes (urease, sucrase, and catalase) showed that the addition of all the materials, including lime, biochar, and carbon black, exhibited positive effects on microbial remediation after soil washing. Furthermore, lime was the most effective material, indicating that low soil pH and high acid-soluble metal concentrations might restrain the activity of soil enzymes. Soil pH and nutrition were the major considerations for microbial remediation during the combined remediation. These findings suggest that the combination of soil washing and in situ immobilization is an effective method to amend the soils contaminated with multiple heavy metals. Copyright © 2018 Elsevier B.V. All rights reserved.

  17. Phytoremediation of radiocesium-contaminated soil in the vicinity of Chernobyl, Ukraine

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dushenkov, S.; Mikheev, A.; Prokhnevsky, A.

    1999-02-01

    Remediation of soil contaminated with {sup 137}Cs remains one of the most challenging tasks after the Chernobyl 1986 accident. The objectives of this research were to (1) identify extractants that may be used to solubilize {sup 137}Cs in soil solution, (2) study the effect of soil amendments on {sup 137}Cs accumulation by plants, and (3) evaluate the applicability of phytoextraction for environmental restoration of soil contaminated with {sup 137}Cs. The availability of {sup 137}Cs to the plants in Chernobyl soil was limited, because this radionuclide was tightly bound to exchange sites of soil particles or incorporated into the crystalline structuremore » of primary and secondary minerals. Out of 20 soil amendments tested to increase {sup 137}Cs desorption/solubility in the soil, ammonium salts were found to be the most practical soil amendment that can potentially increase {sup 137}Cs bioavailability. Among the screened plants, Amaranth cultivars had the highest {sup 137}Cs accumulation. Three sequential crops of Indian mustard grown in one vegetation season at the experimental plot resulted in a small decrease of {sup 137}Cs specific activity within the top 15 cm of soil. Further improvements are necessary to make phytoremediation technology a feasible option for restoration of {sup 137}Cs-contaminated territories.« less

  18. REVIEW OF SEPARATION TECHNOLOGIES FOR TREATING PESTICIDE-CONTAMINATED SOIL

    EPA Science Inventory

    Pesticide contamination results from manufacturing, improper storage, handling, or disposal of pesticides, and from agricultural processes. Since most pesticides are mixtures of different compounds, selecting a remedy for pesticide-contaminated soils can be a complicated process....

  19. Time-dependent changes of zinc speciation in four soils contaminated with zincite or sphalerite.

    PubMed

    Voegelin, Andreas; Jacquat, Olivier; Pfister, Sabina; Barmettler, Kurt; Scheinost, Andreas C; Kretzschmar, Ruben

    2011-01-01

    The long-term speciation of Zn in contaminated soils is strongly influenced by soil pH, clay, and organic matter content as well as Zn loading. In addition, the type of Zn-bearing contaminant entering the soil may influence the subsequent formation of pedogenic Zn species, but systematic studies on such effects are currently lacking. We therefore conducted a soil incubation study in which four soils, ranging from strongly acidic to calcareous, were spiked with 2000 mg/kg Zn using either ZnO (zincite) or ZnS (sphalerite) as the contamination source. The soils were incubated under aerated conditions in moist state for up to four years. The extractability and speciation of Zn were assessed after one, two, and four years using extractions with 0.01 M CaCl(2) and Zn K-edge X-ray absorption fine structure (XAFS) spectroscopy, respectively. After four years, more than 90% of the added ZnO were dissolved in all soils, with the fastest dissolution occurring in the acidic soils. Contamination with ZnO favored the formation of Zn-bearing layered double hydroxides (LDH), even in acidic soils, and to a lesser degree Zn-phyllosilicates and adsorbed Zn species. This was explained by locally elevated pH and high Zn concentrations around dissolving ZnO particles. Except for the calcareous soil, ZnS dissolved more slowly than ZnO, reaching only 26 to 75% of the added ZnS after four years. ZnS dissolved more slowly in the two acidic soils than in the near-neutral and the calcareous soil. Also, the resulting Zn speciation was markedly different between these two pairs of soils: Whereas Zn bound to hydroxy-interlayered clay minerals (HIM) and octahedrally coordinated Zn sorption complexes prevailed in the two acidic soils, Zn speciation in the neutral and the calcareous soil was dominated by Zn-LDH and tetrahedrally coordinated inner-sphere Zn complexes. Our results show that the type of Zn-bearing contaminant phase can have a significant influence on the formation of pedogenic Zn

  20. Chemical methods and phytoremediation of soil contaminated with heavy metals.

    PubMed

    Chen, H M; Zheng, C R; Tu, C; Shen, Z G

    2000-07-01

    The effects of chemical amendments (calcium carbonate (CC), steel sludge (SS) and furnace slag (FS)) on the growth and uptake of cadmium (Cd) by wetland rice, Chinese cabbage and wheat grown in a red soil contaminated with Cd were investigated using a pot experiment. The phytoremediation of heavy metal contaminated soil with vetiver grass was also studied in a field plot experiment. Results showed that treatments with CC, SS and FS decreased Cd uptake by wetland rice, Chinese cabbage and wheat by 23-95% compared with the unamended control. Among the three amendments, FS was the most efficient at suppressing Cd uptake by the plants, probably due to its higher content of available silicon (Si). The concentrations of zinc (Zn), lead (Pb) and Cd in the shoots of vetiver grass were 42-67%, 500-1200% and 120-260% higher in contaminated plots than in control, respectively. Cadmium accumulation by vetiver shoots was 218 g Cd/ha at a soil Cd concentration of 0.33 mg Cd/kg. It is suggested that heavy metal-contaminated soil could be remediated with a combination of chemical treatments and plants.

  1. Potential of different AM fungi (native from As-contaminated and uncontaminated soils) for supporting Leucaena leucocephala growth in As-contaminated soil.

    PubMed

    Schneider, Jerusa; Bundschuh, Jochen; Rangel, Wesley de Melo; Guilherme, Luiz Roberto Guimarães

    2017-05-01

    Arbuscular mycorrhizal (AM) fungi inoculation is considered a potential biotechnological tool for an eco-friendly remediation of hazardous contaminants. However, the mechanisms explaining how AM fungi attenuate the phytotoxicity of metal(oid)s, in particular arsenic (As), are still not fully understood. The influence of As on plant growth and the antioxidant system was studied in Leucaena leucocephala plants inoculated with different isolates of AM fungi and exposed to increasing concentrations of As (0, 35, and 75 mg dm -3 ) in a Typic Quartzipsamment soil. The study was conducted under greenhouse conditions using isolates of AM fungi selected from uncontaminated soils (Acaulospora morrowiae, Rhizophagus clarus, Gigaspora albida; and a mixed inoculum derived from combining these isolates, named AMF Mix) as well as a mix of three isolates from an As-contaminated soil (A. morrowiae, R. clarus, and Paraglomus occultum). After 21 weeks, the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR) were determined in the shoots in addition to measuring plant height and mineral contents. In general, AM fungi have shown multiple beneficial effects on L. leucocephala growth. Although the activity of most of the stress-related enzymes increased in plants associated with AM fungi, the percentage increase caused by adding As to the soil was even greater for non-mycorrhizal plants when compared to AM-fungi inoculated ones, which highlights the phytoprotective effect provided by the AM symbiosis. The highest P/As ratio observed in AM-fungi plants, compared to non-mycorrhizal ones, can be considered a good indicator that the AM fungi alter the pattern of As(V) uptake from As-contaminated soil. Our results underline the role of AM fungi in increasing the tolerance of L. leucocephala to As stress and emphasize the potential of the symbiosis L. leucocephala-R. clarus for As-phytostabilization at moderately As-contaminated

  2. Evaluation of soil amendments as a remediation alternative for cadmium contaminated soils under cacao plantations

    USDA-ARS?s Scientific Manuscript database

    Elevated plant-available cadmium (Cd) in soils results in contamination to cacao (Theobroma cacao L) beans. Effectiveness of vermicompost and zeolite in reducing available Cd in three cacao-growing soils was studied under laboratory conditions. Sorption-desorption experiments were conducted in soils...

  3. Selection of plants for phytoremediation of soils contaminated with radionuclides

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Entry J.A.; Vance, N.C.; Watrud, L.S.

    1996-12-31

    Remediation of soil contaminated with radionuclides typically requires that soil be removed from the site and treated with various dispersing and chelating chemicals. Numerous studies have shown that radionuclides are generally not leached from the top 0.4 meters of soil, where plant roots actively accumulate elements. Restoration of large areas of land contaminated with low levels of radionuclides may be feasible using phytoremediation. Criteria for the selection of plants for phytoremediation, molecular approaches to increase radio nuclide uptake, effects of cultural practices on uptake and assessment of environmental effects of phytoremediation will be discussed.

  4. INCINERATION TREATMENT OF ARSENIC-CONTAMINATED SOIL

    EPA Science Inventory

    An incineration test program was conducted at the U.S. Environmental Protection Agency's Incineration Research Facility to evaluate the potential of incineration as a treatment option for contaminated soils at the Baird and McGuire Superfund site in Holbrook, Massachusetts. The p...

  5. Feasibility of phytoextraction to remediate cadmium and zinc contaminated soils.

    PubMed

    Koopmans, G F; Römkens, P F A M; Fokkema, M J; Song, J; Luo, Y M; Japenga, J; Zhao, F J

    2008-12-01

    A Cd and Zn contaminated soil was mixed and equilibrated with an uncontaminated, but otherwise similar soil to establish a gradient in soil contamination levels. Growth of Thlaspi caerulescens (Ganges ecotype) significantly decreased the metal concentrations in soil solution. Plant uptake of Cd and Zn exceeded the decrease of the soluble metal concentrations by several orders of magnitude. Hence, desorption of metals must have occurred to maintain the soil solution concentrations. A coupled regression model was developed to describe the transfer of metals from soil to solution and plant shoots. This model was applied to estimate the phytoextraction duration required to decrease the soil Cd concentration from 10 to 0.5 mg kg(-1). A biomass production of 1 and 5 t dm ha(-1) yr(-1) yields a duration of 42 and 11 yr, respectively. Successful phytoextraction operations based on T. caerulescens require an increased biomass production.

  6. Biological remediation of oil contaminated soil with earthworms Eisenia andrei

    NASA Astrophysics Data System (ADS)

    Chachina, S. B.; Voronkova, N. A.; Baklanova, O. N.

    2017-08-01

    The study was performed on the bioremediation efficiency of the soil contaminated with oil (20 to 100 g/kg), petroleum (20 to 60 g/kg) and diesel fuel (20 to 40 g/kg) with the help of earthworms E. andrei in the presence of bacteria Pseudomonas, nitrogen fixing bacteria Azotobacter and Clostridium, yeasts Saccharomyces, fungi Aspergillus and Penicillium, as well as Actinomycetales, all being components of biopreparation Baykal-EM. It was demonstrated that in oil-contaminated soil, the content of hydrocarbons decreased by 95-97% after 22 weeks in the presence of worms and bacteria. In petroleum-contaminated soil the content of hydrocarbons decreased by 99% after 22 weeks. The presence of the diesel fuel in the amount of 40 g per 1 kg soil had an acute toxic effect and caused the death of 50 % earthworm species in 14 days. Bacteria introduction enhanced the toxic effect of the diesel fuel and resulted in the death of 60 % earthworms after 7 days.

  7. Health Risk-Based Assessment and Management of Heavy Metals-Contaminated Soil Sites in Taiwan

    PubMed Central

    Lai, Hung-Yu; Hseu, Zeng-Yei; Chen, Ting-Chien; Chen, Bo-Ching; Guo, Horng-Yuh; Chen, Zueng-Sang

    2010-01-01

    Risk-based assessment is a way to evaluate the potential hazards of contaminated sites and is based on considering linkages between pollution sources, pathways, and receptors. These linkages can be broken by source reduction, pathway management, and modifying exposure of the receptors. In Taiwan, the Soil and Groundwater Pollution Remediation Act (SGWPR Act) uses one target regulation to evaluate the contamination status of soil and groundwater pollution. More than 600 sites contaminated with heavy metals (HMs) have been remediated and the costs of this process are always high. Besides using soil remediation techniques to remove contaminants from these sites, the selection of possible remediation methods to obtain rapid risk reduction is permissible and of increasing interest. This paper discusses previous soil remediation techniques applied to different sites in Taiwan and also clarified the differences of risk assessment before and after soil remediation obtained by applying different risk assessment models. This paper also includes many case studies on: (1) food safety risk assessment for brown rice growing in a HMs-contaminated site; (2) a tiered approach to health risk assessment for a contaminated site; (3) risk assessment for phytoremediation techniques applied in HMs-contaminated sites; and (4) soil remediation cost analysis for contaminated sites in Taiwan. PMID:21139851

  8. Efficient phytoremediation of organic contaminants in soils using plant-endophyte partnerships.

    PubMed

    Feng, Nai-Xian; Yu, Jiao; Zhao, Hai-Ming; Cheng, Yu-Ting; Mo, Ce-Hui; Cai, Quan-Ying; Li, Yan-Wen; Li, Hui; Wong, Ming-Hung

    2017-04-01

    Soil pollution with organic contaminants is one of the most intractable environmental problems today, posing serious threats to humans and the environment. Innovative strategies for remediating organic-contaminated soils are critically needed. Phytoremediation, based on the synergistic actions of plants and their associated microorganisms, has been recognized as a powerful in situ approach to soil remediation. Suitable combinations of plants and their associated endophytes can improve plant growth and enhance the biodegradation of organic contaminants in the rhizosphere and/or endosphere, dramatically expediting the removal of organic pollutants from soils. However, for phytoremediation to become a more widely accepted and predictable alternative, a thorough understanding of plant-endophyte interactions is needed. Many studies have recently been conducted on the mechanisms of endophyte-assisted phytoremediation of organic contaminants in soils. In this review, we highlight the superiority of organic pollutant-degrading endophytes for practical applications in phytoremediation, summarize alternative strategies for improving phytoremediation, discuss the fundamental mechanisms of endophyte-assisted phytoremediation, and present updated information regarding the advances, challenges, and new directions in the field of endophyte-assisted phytoremediation technology. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Remediation of saturated soil contaminated with petroleum products using air sparging with thermal enhancement.

    PubMed

    Mohamed, A M I; El-menshawy, Nabil; Saif, Amany M

    2007-05-01

    Pollutants in the form of non-aqueous phase liquids (NAPLs), such as petroleum products, pose a serious threat to the soil and groundwater. A mathematical model was derived to study the unsteady pollutant concentrations through water saturated contaminated soil under air sparging conditions for different NAPLs and soil properties. The comparison between the numerical model results and the published experimental results showed acceptable agreement. Furthermore, an experimental study was conducted to remove NAPLs from the contaminated soil using the sparging air technique, considering the sparging air velocity, air temperature, soil grain size and different contaminant properties. This study showed that sparging air at ambient temperature through the contaminated soil can remove NAPLs, however, employing hot air sparging can provide higher contaminant removal efficiency, by about 9%. An empirical correlation for the volatilization mass transfer coefficient was developed from the experimental results. The dimensionless numbers used were Sherwood number (Sh), Peclet number (Pe), Schmidt number (Sc) and several physical-chemical properties of VOCs and porous media. Finally, the estimated volatilization mass transfer coefficient was used for calculation of the influence of heated sparging air on the spreading of the NAPL plume through the contaminated soil.

  10. Use of surfactants for the remediation of contaminated soils: a review.

    PubMed

    Mao, Xuhui; Jiang, Rui; Xiao, Wei; Yu, Jiaguo

    2015-03-21

    Due to the great harm caused by soil contamination, there is an increasing interest to apply surfactants to the remediation of a variety of contaminated soils worldwide. This review article summarizes the findings of recent literatures regarding remediation of contaminated soils/sites using surfactants as an enhancing agent. For the surfactant-based remedial technologies, the adsorption behaviors of surfactants onto soil, the solubilizing capability of surfactants, and the toxicity and biocompatibility of surfactants are important considerations. Surfactants can enhance desorption of pollutants from soil, and promote bioremediation of organics by increasing bioavailability of pollutants. The removal of heavy metals and radionuclides from soils involves the mechanisms of dissolution, surfactant-associated complexation, and ionic exchange. In addition to the conventional ionic and nonionic surfactants, gemini surfactants and biosurfactants are also applied to soil remediation due to their benign features like lower critical micelle concentration (CMC) values and better biocompatibility. Mixed surfactant systems and combined use of surfactants with other additives are often adopted to improve the overall performance of soil washing solution for decontamination. Worldwide the field studies and full-scale remediation using surfactant-based technologies are yet limited, however, the already known cases reveal the good prospect of applying surfactant-based technologies to soil remediation. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Effects of arbuscular mycorrhizal inoculation on plants growing on arsenic contaminated soil.

    PubMed

    Jankong, P; Visoottiviseth, P

    2008-07-01

    Arbuscular mycorrhizal fungi (AMF) may play an important role in phytoremediation of As-contaminated soil. In this study the effects of AMF (Glomus mosseae, Glomus intraradices and Glomus etunicatum) on biomass production and arsenic accumulation in Pityrogramma calomelanos, Tagetes erecta and Melastoma malabathricum were investigated. Soil (243 +/- 13 microg As g(-1)) collected from Ron Phibun District, an As-contaminated area in Thailand, was used in a greenhouse experiment. The results showed different effects of AMF on phytoremediation of As-contaminated soil by different plant species. For P. calomelanos and T. erecta, AMF reduced only arsenic accumulation in plants but had no significant effect on plant growth. In contrast, AMF improved growth and arsenic accumulation in M. malabathricum. These findings show the importance of understanding different interactions between AMF and their host plants for enhancing phytoremediation of As-contaminated soils.

  12. Combining phytoextraction and biochar addition improves soil biochemical properties in a soil contaminated with Cd.

    PubMed

    Lu, Huanping; Li, Zhian; Fu, Shenglei; Méndez, Ana; Gascó, Gabriel; Paz-Ferreiro, Jorge

    2015-01-01

    The main goal of phytoremediation is to improve ecosystem functioning. Soil biochemical properties are considered as effective indicators of soil quality and are sensitive to various environmental stresses, including heavy metal contamination. The biochemical response in a soil contaminated with cadmium was tested after several treatments aimed to reduce heavy metal availability including liming, biochar addition and phytoextraction using Amaranthus tricolor L. Two biochars were added to the soil: eucalyptus pyrolysed at 600 °C (EB) and poultry litter at 400 °C (PLB). Two liming treatments were chosen with the aim of bringing soil pH to the same values as in the treatments EB and PLB. The properties studied included soil microbial biomass C, soil respiration and the activities of invertase, β-glucosidase, β-glucosaminidase, urease and phosphomonoesterase. Both phytoremediation and biochar addition improved soil biochemical properties, although results were enzyme specific. For biochar addition these changes were partly, but not exclusively, mediated by alterations in soil pH. A careful choice of biochar must be undertaken to optimize the remediation process from the point of view of metal phytoextraction and soil biological activity. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. REMEDIATION OF SOILS CONTAMINATED WITH WOOD-TREATMENT CHEMICALS (PCP AND CREOSOTE)

    EPA Science Inventory

    PCP and creosote PAHs are found in most of the contaminated soils at wood-treatment sites. The treatment methods currently being used for such soils include soil washing, incineration, and biotreatment. Soil washing involves removal of the hazardous chemicals from soils ...

  14. REMEDIATION OF RADIUM FROM CONTAMINATED SOIL

    EPA Science Inventory

    The objective of this study was to demonstrate the application of a physico-chemical separation process for the removal of radium from a sample of contaminated soil at the Ottawa, Illinois, site near Chicago. The size/activity distribution analyzed among the particles coarser tha...

  15. Remediation of transuranic-contaminated coral soil at Johnston Atoll using the segmented gate system

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bramlitt, E.; Johnson, N.

    1994-12-31

    Thermo Analytical, Inc. (TMA) has developed a system to remove clean soil from contaminated soil. The system consists of a soil conveyor, an array of radiation detectors toward the conveyor feed end, a gate assembly at the conveyor discharge end, and two additional conveyors which move discharged soil to one or another paths. The gate assembly is as wide as the ``sorter conveyor,`` and it has eight individual gates or segments. The segments automatically open or close depending on the amount of radioactivity present. In one position they pass soil to a clean soil conveyor, and in the other positionmore » they let soil fall to a hot soil conveyor. The soil sorting process recovers clean soil for beneficial use and it substantially reduces the quantity of soil which must be decontaminated or prepared for waste disposal. The Segmented Gate System (SGS) was developed for the cleanup of soil contaminated with some transuranium elements at Johnston Atoll. It has proven to be an effective means for recovering clean soil and verifying that soil is clean, minimizing the quantity of truly contaminated soil, and providing measures of contamination for waste transport and disposal. TMA is constructing a small, transportable soil cleanup as it is confident the SGS technology can be adapted to soils and contaminants other than those at Johnston Atoll. It will use this transportable plant to demonstrate the technology and to develop site specific parameters for use in designing plants to meet cleanup needs.« less

  16. Microbial expression profiles in the rhizosphere of willows depend on soil contamination

    PubMed Central

    Yergeau, Etienne; Sanschagrin, Sylvie; Maynard, Christine; St-Arnaud, Marc; Greer, Charles W

    2014-01-01

    The goal of phytoremediation is to use plants to immobilize, extract or degrade organic and inorganic pollutants. In the case of organic contaminants, plants essentially act indirectly through the stimulation of rhizosphere microorganisms. A detailed understanding of the effect plants have on the activities of rhizosphere microorganisms could help optimize phytoremediation systems and enhance their use. In this study, willows were planted in contaminated and non-contaminated soils in a greenhouse, and the active microbial communities and the expression of functional genes in the rhizosphere and bulk soil were compared. Ion Torrent sequencing of 16S rRNA and Illumina sequencing of mRNA were performed. Genes related to carbon and amino-acid uptake and utilization were upregulated in the willow rhizosphere, providing indirect evidence of the compositional content of the root exudates. Related to this increased nutrient input, several microbial taxa showed a significant increase in activity in the rhizosphere. The extent of the rhizosphere stimulation varied markedly with soil contamination levels. The combined selective pressure of contaminants and rhizosphere resulted in higher expression of genes related to competition (antibiotic resistance and biofilm formation) in the contaminated rhizosphere. Genes related to hydrocarbon degradation were generally more expressed in contaminated soils, but the exact complement of genes induced was different for bulk and rhizosphere soils. Together, these results provide an unprecedented view of microbial gene expression in the plant rhizosphere during phytoremediation. PMID:24067257

  17. Ecotoxicological evaluation of diesel-contaminated soil before and after a bioremediation process.

    PubMed

    Molina-Barahona, L; Vega-Loyo, L; Guerrero, M; Ramírez, S; Romero, I; Vega-Jarquín, C; Albores, A

    2005-02-01

    Evaluation of contaminated sites is usually performed by chemical analysis of pollutants in soil. This is not enough either to evaluate the environmental risk of contaminated soil nor to evaluate the efficiency of soil cleanup techniques. Information on the bioavailability of complex mixtures of xenobiotics and degradation products cannot be totally provided by chemical analytical data, but results from bioassays can integrate the effects of pollutants in complex mixtures. In the preservation of human health and environment quality, it is important to assess the ecotoxicological effects of contaminated soils to obtain a better evaluation of the healthiness of this system. The monitoring of a diesel-contaminated soil and the evaluation of a bioremediation technique conducted on a microcosm scale were performed by a battery of ecotoxicological tests including phytotoxicity, Daphnia magna, and nematode assays. In this study we biostimulated the native microflora of soil contaminated with diesel by adding nutrients and crop residue (corn straw) as a bulking agent and as a source of microorganisms and nutrients; in addition, moisture was adjusted to enhance diesel removal. The bioremediation process efficiency was evaluated directly by an innovative, simple phytotoxicity test system and the diesel extracts by Daphnia magna and nematode assays. Contaminated soil samples were revealed to have toxic effects on seed germination, seedling growth, and Daphnia survival. After biostimulation, the diesel concentration was reduced by 50.6%, and the soil samples showed a significant reduction in phytotoxicity (9%-15%) and Daphnia assays (3-fold), confirming the effectiveness of the bioremediation process. Results from our microcosm study suggest that in addition to the evaluation of the bioremediation processes efficiency, toxicity testing is different with organisms representative of diverse phylogenic levels. The integration of analytical, toxicological and bioremediation data

  18. Influence of biochar and compost on phytoremediation of oil-contaminated soil.

    PubMed

    Saum, Lindsey; Jiménez, Macario Bacilio; Crowley, David

    2018-01-02

    The use of pyrolyzed carbon, biochar, as a soil amendment is of potential interest for improving phytoremediation of soil that has been contaminated by petroleum hydrocarbons. To examine this question, the research reported here compared the effects of biochar, plants (mesquite tree seedlings), compost and combinations of these treatments on the rate of biodegradation of oil in a contaminated soil and the population size of oil-degrading bacteria. The presence of mesquite plants significantly enhanced oil degradation in all treatments except when biochar was used as the sole amendment without compost. The greatest extent of oil degradation was achieved in soil planted with mesquite and amended with compost (44% of the light hydrocarbon fraction). Most probable number assays showed that biochar generally reduced the population size of the oil-degrading community. The results of this study suggest that biochar addition to petroleum-contaminated soils does not improve the rate of bioremediation. In contrast, the use of plants and compost additions to soil are confirmed as important bioremediation technologies.

  19. Tracing thallium contamination in soils using isotopes

    NASA Astrophysics Data System (ADS)

    Vaněk, Aleš; Grösslová, Zuzana; Mihaljevič, Martin; Ettler, Vojtěch; Trubač, Jakub; Teper, Leslaw; Cabala, Jerzy; Rohovec, Jan; Penížek, Vít; Zádorová, Tereza; Pavlů, Lenka; Holubík, Ondřej; Drábek, Ondřej; Němeček, Karel; Houška, Jakub; Ash, Christopher

    2017-04-01

    We report the thallium (Tl) isotope record in moderately contaminated soils, which have been historically affected by emissions from coal-fired power plants. Our findings clearly demonstrate that Tl of anthropogenic (high-temperature) origin with light isotope composition was deposited onto the studied soils, where heavier Tl (ɛ205Tl -1) naturally occurs. The results show a positive linear relationship (R2 = 0.71) between 1/Tl and the isotope record, as determined for all the soils and bedrocks, also indicative of binary Tl mixing between two dominant reservoirs. We also identified significant Tl isotope variations within the products from coal combustion and thermo-desorption experiments with local Tl-rich coal pyrite. Bottom ash exhibited the heaviest Tl isotope composition (ɛ205Tl 0), followed by fly ash (ɛ205Tl between -2.5 and -2.8) and volatile Tl fractions (ɛ205Tl between -6.2 and -10.3), suggesting partial Tl isotope fractionations. Despite the evident role of soil processes in the isotope redistribution, we demonstrate that Tl contamination can be traced in soils, and propose that the isotope data represent a possible tool to aid our understanding of post-depositional Tl dynamics in surface environments for the future. This research was supported by the Czech Science Foundation (grant no. 14-01866S and 17-03211S).

  20. Assessment of Soil-Gas and Soil Contamination at the Former Military Police Range, Fort Gordon, Georgia, 2009-2010

    USGS Publications Warehouse

    Falls, W. Fred; Caldwell, Andral W.; Guimaraes, Wladmir B.; Ratliff, W. Hagan; Wellborn, John B.; Landmeyer, James E.

    2011-01-01

    Soil gas and soil were assessed for organic and inorganic contaminants at the former military police range at Fort Gordon, Georgia, from May to September 2010. The assessment evaluated organic contaminants in soil-gas samplers and inorganic contaminants in soil samples. This assessment was conducted to provide environmental contamination data to Fort Gordon pursuant to requirements of the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. Soil-gas samplers deployed and collected from May 20 to 24, 2010, identified masses above method detection level for total petroleum hydrocarbons, gasoline-related and diesel-related compounds, and chloroform. Most of these detections were in the southwestern quarter of the study area and adjacent to the road on the eastern boundary of the site. Nine of the 11 chloroform detections were in the southern half of the study area. One soil-gas sampler deployed adjacent to the road on the southern boundary of the site detected a mass of tetrachloroethene greater than, but close to, the method detection level of 0.02 microgram. For soil-gas samplers deployed and collected from September 15 to 22, 2010, none of the selected organic compounds classified as chemical agents and explosives were detected above method detection levels. Inorganic concentrations in the five soil samples collected at the site did not exceed the U.S. Environmental Protection Agency regional screening levels for industrial soil and were at or below background levels for similar rocks and strata in South Carolina.

  1. Bioremediation of poly-aromatic hydrocarbon (PAH)-contaminated soil by composting

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Loick, N.; Hobbs, P.J.; Hale, M.D.C.

    2009-07-01

    This paper presents a comprehensive and critical review of research on different co-composting approaches to bioremediate hydrocarbon contaminated soil, organisms that have been found to degrade PAHs, and PAH breakdown products. Advantages and limitations of using certain groups of organisms and recommended areas of further research effort are identified. Studies investigating the use of composting techniques to treat contaminated soil are broad ranging and differ in many respects, which makes comparison of the different approaches very difficult. Many studies have investigated the use of specific bio-additives in the form of bacteria or fungi with the aim of accelerating contaminant removal;more » however, few have employed microbial consortia containing organisms from both kingdoms despite knowledge suggesting synergistic relationships exist between them in contaminant removal. Recommendations suggest that further studies should attempt to systemize the investigations of composting approaches to bio-remediate PAH-contaminated soil, to focus on harnessing the biodegradative capacity of both bacteria and fungi to create a cooperative environment for PAH degradation, and to further investigate the array of PAHs that can be lost during the composting process by either leaching or volatilization.« less

  2. Toxicity tests of soil contaminated by recycling of scrap plastics

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wong, M.H.; Chui, V.W.

    The present investigation studied the toxicity of soil contaminated by untreated discharge from a factory that recycles used plastics. The nearby agricultural areas and freshwater fish ponds were polluted with high concentrations of Cu, Ni, and Mn. Water extracts from the contaminated soil retarded root growth of Brassica chinensis (Chinese white cabbage) and Cynodon dactylon (Bermuda grass) where their seeds were obtained commercially. The contaminated populations of C. dactylon, Panicum repen (panic grass), and Imperata cylindrica (wooly grass) were able to withstand higher concentrations of Cu, Ni, and Mn, especially C. dactylon, when compared with their uncontaminated counterparts.

  3. Perceived Benefits of Participation and Risks of Soil Contamination in St. Louis Urban Community Gardens.

    PubMed

    Wong, Roger; Gable, Leah; Rivera-Núñez, Zorimar

    2018-06-01

    Community gardens are credited for promoting health within neighborhoods, by increasing healthy food intake and exercise frequency. These benefits, however, are potentially undermined as urban soils are often contaminated from industrial legacies. The purpose of this study was to examine the perceived benefits of participation and risks of soil contamination within urban community gardens, and factors associated with soil contamination concerns. Ninety-three gardeners were interviewed across 20 community gardens in St. Louis, Missouri between June and August 2015. Surveys included questions on demographics, gardening practices, and perceptions of community gardening. Multilevel logistic models assessed how gardener demographics, gardening practices, and garden characteristics were associated with soil contamination concerns. Common perceived benefits of community gardening were community building (68.8%), healthy and fresh food (35.5%), and gardening education (18.3%). Most gardeners (62.4%) were not concerned about soil contamination, but nearly half (48.4%) stated concerns about heavy metals. Black race was significantly associated with soil contamination concerns (OR 5.47, 95% CI 1.00-30.15, p = .04). Community gardens offer numerous social and health benefits. Although most gardeners were not concerned about soil contamination, black gardeners were more likely to have concerns. Garden leaders should provide resources to gardeners to learn about soil contamination and methods to manage their risk, particularly in minority neighborhoods.

  4. Acute toxicity assessment of explosive-contaminated soil extracting solution by luminescent bacteria assays.

    PubMed

    Xu, Wenjie; Jiang, Zhenming; Zhao, Quanlin; Zhang, Zhenzhong; Su, Hongping; Gao, Xuewen; Ye, Zhengfang

    2016-11-01

    Explosive-contaminated soil is harmful to people's health and the local ecosystem. The acute toxicity of its extracting solution was tested by bacterial luminescence assay using three kinds of luminescent bacteria to characterize the toxicity of the soil. An orthogonal test L 16 (4 5 ) was designed to optimize the soil extracting conditions. The optimum extracting conditions were obtained when the ultrasonic extraction time, ultrasonic extraction temperature, and the extraction repeat times were 6 h, 40 °C, and three, respectively. Fourier transform infrared spectroscopy (FTIR) results showed that the main components of the contaminated soil's extracting solution were 2,4-dinitrotoluene-3-sulfonate (2,4-DNT-3-SO 3 - ); 2,4-dinitrotoluene-5-sulfonate (2,4-DNT-5-SO 3 - ); and 2,6-dinitrotoluene (2,6-DNT). Compared with Photobacterium phosphoreum and Vibrio fischeri, Vibrio qinghaiensis sp. Nov. is more suitable for assessing the soil extracting solution's acute toxicity. Soil washing can remove most of the contaminants toxic to luminescent bacterium Vibrio qinghaiensis sp. Nov., suggesting that it may be a potential effective remediation method for explosive-contaminated soil.

  5. Relative bioavailability of arsenic contaminated soils in a mouse model

    EPA Science Inventory

    Exposure to As contaminated soils compels extensive soil cleanups so that human health risks are minimized. In order to improve exposure estimates and potentially reduce remediation costs, determination of the bioavailability of As in soils is needed. The objective of this study ...

  6. Bioremediation of oil-contaminated soil using Candida catenulata and food waste.

    PubMed

    Joo, Hung-Soo; Ndegwa, Pius M; Shoda, Makoto; Phae, Chae-Gun

    2008-12-01

    Even though petroleum-degrading microorganisms are widely distributed in soil and water, they may not be present in sufficient numbers to achieve contaminant remediation. In such cases, it may be useful to inoculate the polluted area with highly effective petroleum-degrading microbial strains to augment the exiting ones. In order to identify a microbial strain for bioaugmentation of oil-contaminated soil, we isolated a microbial strain with high emulsification and petroleum hydrocarbon degradation efficiency of diesel fuel in culture. The efficacy of the isolated microbial strain, identified as Candida catenulata CM1, was further evaluated during composting of a mixture containing 23% food waste and 77% diesel-contaminated soil including 2% (w/w) diesel. After 13 days of composting, 84% of the initial petroleum hydrocarbon was degraded in composting mixes containing a powdered form of CM1 (CM1-solid), compared with 48% of removal ratio in control reactor without inoculum. This finding suggests that CM1 is a viable microbial strain for bioremediation of oil-contaminated soil with food waste through composting processes.

  7. Decontamination of Petroleum-Contaminated Soils Using The Electrochemical Technique: Remediation Degree and Energy Consumption.

    PubMed

    Streche, Constantin; Cocârţă, Diana Mariana; Istrate, Irina-Aura; Badea, Adrian Alexandru

    2018-02-19

    Currently, there are different remediation technologies for contaminated soils, but the selection of the best technology must be not only the treatment efficiency but also the energy consumption (costs) during its application. This paper is focused on assessing energy consumption related to the electrochemical treatment of polluted soil with petroleum hydrocarbons. In the framework of a research project, two types of experiments were conducted using soil that was artificially contaminated with diesel fuel at the same level of contamination. The experimental conditions considered for each experiment were: different amounts of contaminated soils (6 kg and 18 kg, respectively), the same current intensity level (0.25A and 0.5A), three different contamination degrees (1%, 2.5% and 5%) and the same time for application of the electrochemical treatment. The remediation degree concerning the removal of petroleum hydrocarbons from soil increased over time by approximately 20% over 7 days. With regard to energy consumption, the results revealed that with an increase in the quantity of treated soil of approximately three times, the specific energy consumption decreased from 2.94 kWh/kg treated soil to 1.64 kWh/kg treated soil.

  8. Assessment of Soil-Gas, Surface-Water, and Soil Contamination at the Installation Railhead, Fort Gordon, Georgia, 2008-2009

    USGS Publications Warehouse

    Landmeyer, James E.; Harrelson, Larry G.; Ratliff, W. Hagan; Wellborn, John B.

    2010-01-01

    The U.S. Geological Survey, in cooperation with the U.S. Department of the Army Environmental and Natural Resources Management Office of the U.S. Army Signal Center and Fort Gordon, assessed soil gas, surface water, and soil for contaminants at the Installation Railhead (IR) at Fort Gordon, Georgia, from October 2008 to September 2009. The assessment included delineation of organic contaminants present in soil-gas samples beneath the IR, and in a surface-water sample collected from an unnamed tributary to Marcum Branch in the western part of the IR. Inorganic contaminants were determined in a surface-water sample and in soil samples. This assessment was conducted to provide environmental contamination data to Fort Gordon personnel pursuant to requirements of the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. Soil-gas samples collected within a localized area on the western part of the IR contained total petroleum hydrocarbons; benzene, toluene, ethylbenzene, and total xylenes (referred to as BTEX); and naphthalene above the method detection level. These soil-gas samples were collected where buildings had previously stood. Soil-gas samples collected within a localized area contained perchloroethylene (PCE). These samples were collected where buildings 2410 and 2405 had been. Chloroform and toluene were detected in a surface-water sample collected from an unnamed tributary to Marcum Branch but at concentrations below the National Primary Drinking Water Standard maximum contaminant level (MCL) for each compound. Iron was detected in the surface-water sample at 686 micrograms per liter (ug/L) and exceeded the National Secondary Drinking Water Standard MCL for iron. Metal concentrations in composite soil samples collected at three locations from land surface to a depth of 6 inches did not exceed the U.S. Environmental Protection Agency Regional Screening Levels for industrial soil.

  9. Changes in the microbial community during bioremediation of gasoline-contaminated soil.

    PubMed

    Leal, Aline Jaime; Rodrigues, Edmo Montes; Leal, Patrícia Lopes; Júlio, Aline Daniela Lopes; Fernandes, Rita de Cássia Rocha; Borges, Arnaldo Chaer; Tótola, Marcos Rogério

    We aimed to verify the changes in the microbial community during bioremediation of gasoline-contaminated soil. Microbial inoculants were produced from successive additions of gasoline to municipal solid waste compost (MSWC) previously fertilized with nitrogen-phosphorous. To obtain Inoculant A, fertilized MSWC was amended with gasoline every 3 days during 18 days. Inoculant B received the same application, but at every 6 days. Inoculant C included MSWC fertilized with N-P, but no gasoline. The inoculants were applied to gasoline-contaminated soil at 10, 30, or 50g/kg. Mineralization of gasoline hydrocarbons in soil was evaluated by respirometric analysis. The viability of the inoculants was evaluated after 103 days of storage under refrigeration or room temperature. The relative proportions of microbial groups in the inoculants and soil were evaluated by FAME. The dose of 50g/kg of inoculants A and B led to the largest CO 2 emission from soil. CO 2 emissions in treatments with inoculant C were inversely proportional to the dose of inoculant. Heterotrophic bacterial counts were greater in soil treated with inoculants A and B. The application of inoculants decreased the proportion of actinobacteria and increased of Gram-negative bacteria. Decline in the density of heterotrophic bacteria in inoculants occurred after storage. This reduction was bigger in inoculants stored at room temperature. The application of stored inoculants in gasoline-contaminated soil resulted in a CO 2 emission twice bigger than that observed in uninoculated soil. We concluded that MSWC is an effective material for the production of microbial inoculants for the bioremediation of gasoline-contaminated soil. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  10. Soil bioindicators as a usefull tools for land management and spatial planning processes: a case-study of prioritization of contaminated soil remediation

    NASA Astrophysics Data System (ADS)

    Grand, Cécile; Pauget, Benjamin; Villenave, Cécile; Le Guédard, Marina; Piron, Denis; Nau, Jean-François; Pérès, Guénola

    2017-04-01

    When setting up new land management, contaminated site remediation or soil use change are sometimes necessary to ensure soil quality and the restoration of the ecosystem services. The biological characterization of the soil can be used as complementary information to chemical data in order to better define the conditions for operating. Then, in the context of urban areas, elements on the soil biological quality can be taken into consideration to guide the land development. To assess this "biological state of soil health", some biological tools, called bioindicators, could provide comprehensive information to understand and predict the functioning of the soil ecosystem. In this context, a city of 200 thousand inhabitants has decided to integrate soil bioindicators in their soil diagnostic for their soil urban management. This city had to elaborate a spatial soil management in urban areas which presented soil contamination linked to a complex industrial history associated with bad uses of gardens not always safe for the environment. The project will lead to establish a Natural Urban Park (PNU) in order to develop recreational and leisure activities in a quality environment. In order to complete the knowledge of soil contamination and to assess the transfer of contaminants to the terrestrial ecosystem, a biological characterization of soils located in different areas was carried out using six bioindicators: bioindicators of accumulation which allowed to evaluate the transfers of soil contaminants towards the first 2 steps of a trophic chain (plants and soil fauna, e.g. snails), bioindicators of effects (Omega 3 index was used to assess the effects of soil contamination and to measure their impact on plants), bioindicators of soil functioning (measurement of microbial biomass, nematodes and earthworm community) ; the interest of these last bioindicators is that they also act on the functioning of ecosystems as on the dynamics of organic matter (mineralization) but also

  11. Phytoremediation of fuel oil and lead co-contaminated soil by Chromolaena odorata in association with Micrococcus luteus.

    PubMed

    Jampasri, Kongkeat; Pokethitiyook, Prayad; Kruatrachue, Maleeya; Ounjai, Puey; Kumsopa, Acharaporn

    2016-10-02

    Phytoremediation is widely promoted as a cost-effective technology for treating heavy metal and total petroleum hydrocarbon (TPH) co-contaminated soil. This study investigated the concurrent removal of TPHs and Pb in co-contaminated soil (27,000 mg kg(-1) TPHs, 780 mg kg(-1) Pb) by growing Siam weed (Chromolaena odorata) in a pot experiment for 90 days. There were four treatments: co-contaminated soil; co-contaminated soil with C. odorata only; co-contaminated soil with C. odorata and Micrococcus luteus inoculum; and co-contaminated soil with M. luteus only. C. odorata survived and grew well in the co-contaminated soil. C. odorata with M. luteus showed the highest Pb accumulation (513.7 mg kg(-1)) and uptake (7.7 mg plant(-1)), and the highest reduction percentage of TPHs (52.2%). The higher TPH degradation in vegetated soils indicated the interaction between the rhizosphere microorganisms and plants. The results suggested that C. odorata together with M. luteus and other rhizosphere microorganisms is a promising candidate for the removal of Pb and TPHs in co-contaminated soils.

  12. Evaluation of Soil Contamination Indices in a Mining Area of Jiangxi, China

    PubMed Central

    Wu, Jin; Teng, Yanguo; Lu, Sijin; Wang, Yeyao; Jiao, Xudong

    2014-01-01

    There is currently a wide variety of methods used to evaluate soil contamination. We present a discussion of the advantages and limitations of different soil contamination assessment methods. In this study, we analyzed seven trace elements (As, Cd, Cr, Cu, Hg, Pb, and Zn) that are indicators of soil contamination in Dexing, a city in China that is famous for its vast nonferrous mineral resources in China, using enrichment factor (EF), geoaccumulation index (Igeo), pollution index (PI), and principal component analysis (PCA). The three contamination indices and PCA were then mapped to understand the status and trends of soil contamination in this region. The entire study area is strongly enriched in Cd, Cu, Pb, and Zn, especially in areas near mine sites. As and Hg were also present in high concentrations in urban areas. Results indicated that Cr in this area originated from both anthropogenic and natural sources. PCA combined with Geographic Information System (GIS) was successfully used to discriminate between natural and anthropogenic trace metals. PMID:25397401

  13. Green waste compost as an amendment during induced phytoextraction of mercury-contaminated soil.

    PubMed

    Smolinska, Beata

    2015-03-01

    Phytoextraction of mercury-contaminated soils is a new strategy that consists of using the higher plants to make the soil contaminant nontoxic. The main problem that occurs during the process is the low solubility and bioavailability of mercury in soil. Therefore, some soil amendments can be used to increase the efficiency of the Hg phytoextraction process. The aim of the investigation was to use the commercial compost from municipal green wastes to increase the efficiency of phytoextraction of mercury-contaminated soil by Lepidium sativum L. plants and determine the leaching of Hg after compost amendment. The result of the study showed that Hg can be accumulated by L. sativum L. The application of compost increased both the accumulation by whole plant and translocation of Hg to shoots. Compost did not affect the plant biomass and its biometric parameters. Application of compost to the soil decreased the leaching of mercury in both acidic and neutral solutions regardless of growing medium composition and time of analysis. Due to Hg accumulation and translocation as well as its potential leaching in acidic and neutral solution, compost can be recommended as a soil amendment during the phytoextraction of mercury-contaminated soil.

  14. Ex situ treatment of hydrocarbon-contaminated soil using biosurfactants from Lactobacillus pentosus.

    PubMed

    Moldes, Ana Belén; Paradelo, Remigio; Rubinos, David; Devesa-Rey, Rosa; Cruz, José Manuel; Barral, María Teresa

    2011-09-14

    The utilization of biosurfactants for the bioremediation of contaminated soil is not yet well established, because of the high production cost of biosurfactants. Consequently, it is interesting to look for new biosurfactants that can be produced at a large scale, and it can be employed for the bioremediation of contaminated sites. In this work, biosurfactants from Lactobacillus pentosus growing in hemicellulosic sugars solutions, with a similar composition of sugars found in trimming vine shoot hydrolysates, were employed in the bioremediation of soil contaminated with octane. It was observed that the presence of biosurfactant from L. pentosus accelerated the biodegradation of octane in soil. After 15 days of treatment, biosurfactants from L. pentosus reduced the concentration of octane in the soil to 58.6 and 62.8%, for soil charged with 700 and 70,000 mg/kg of hydrocarbon, respectively, whereas after 30 days of treatment, 76% of octane in soil was biodegraded in both cases. In the absence of biosurfactant and after 15 days of incubation, only 1.2 and 24% of octane was biodegraded in soil charged with 700 and 70,000 mg/kg of octane, respectively. Thus, the use of biosurfactants from L. pentosus, as part of a well-designed bioremediation process, can provide mechanisms to mobilize the target contaminants from the soil surface to make them more available to the microbial population.

  15. Remediation of soils contaminated with heavy metals with an emphasis on immobilization technology.

    PubMed

    Derakhshan Nejad, Zahra; Jung, Myung Chae; Kim, Ki-Hyun

    2018-06-01

    The major frequent contaminants in soil are heavy metals which may be responsible for detrimental health effects. The remediation of heavy metals in contaminated soils is considered as one of the most complicated tasks. Among different technologies, in situ immobilization of metals has received a great deal of attention and turned out to be a promising solution for soil remediation. In this review, remediation methods for removal of heavy metals in soil are explored with an emphasis on the in situ immobilization technique of metal(loid)s. Besides, the immobilization technique in contaminated soils is evaluated through the manipulation of the bioavailability of heavy metals using a range of soil amendment conditions. This technique is expected to efficiently alleviate the risk of groundwater contamination, plant uptake, and exposure to other living organisms. The efficacy of several amendments (e.g., red mud, biochar, phosphate rock) has been examined to emphasize the need for the simultaneous measurement of leaching and the phytoavailability of heavy metals. In addition, some amendments that are used in this technique are inexpensive and readily available in large quantities because they have been derived from bio-products or industrial by-products (e.g., biochar, red mud, and steel slag). Among different amendments, iron-rich compounds and biochars show high efficiency to remediate multi-metal contaminated soils. Thereupon, immobilization technique can be considered a preferable option as it is inexpensive and easily applicable to large quantities of contaminants derived from various sources.

  16. Microbial activity, arbuscular mycorrhizal fungi and inoculation of woody plants in lead contaminated soil.

    PubMed

    Gattai, Graziella S; Pereira, Sônia V; Costa, Cynthia M C; Lima, Cláudia E P; Maia, Leonor C

    2011-07-01

    The goals of this study were to evaluate the microbial activity, arbuscular mycorrhizal fungi and inoculation of woody plants (Caesalpinia ferrea, Mimosa tenuiflora and Erythrina velutina) in lead contaminated soil from the semi-arid region of northeastern of Brazil (Belo Jardim, Pernambuco). Dilutions were prepared by adding lead contaminated soil (270 mg Kg(-1)) to uncontaminated soil (37 mg Pb Kg soil(-1)) in the proportions of 7.5%, 15%, and 30% (v:v). The increase of lead contamination in the soil negatively influenced the amount of carbon in the microbial biomass of the samples from both the dry and rainy seasons and the metabolic quotient only differed between the collection seasons in the 30% contaminated soil. The average value of the acid phosphatase activity in the dry season was 2.3 times higher than observed during the rainy season. There was no significant difference in the number of glomerospores observed between soils and periods studied. The most probable number of infective propagules was reduced for both seasons due to the excess lead in soil. The mycorrhizal colonization rate was reduced for the three plant species assayed. The inoculation with arbuscular mycorrhizal fungi benefited the growth of Erythrina velutina in lead contaminated soil.

  17. Microbial activity, arbuscular mycorrhizal fungi and inoculation of woody plants in lead contaminated soil

    PubMed Central

    Gattai, Graziella S.; Pereira, Sônia V.; Costa, Cynthia M. C.; Lima, Cláudia E. P.; Maia, Leonor C.

    2011-01-01

    The goals of this study were to evaluate the microbial activity, arbuscular mycorrhizal fungi and inoculation of woody plants (Caesalpinia ferrea, Mimosa tenuiflora and Erythrina velutina) in lead contaminated soil from the semi-arid region of northeastern of Brazil (Belo Jardim, Pernambuco). Dilutions were prepared by adding lead contaminated soil (270 mg Kg-1) to uncontaminated soil (37 mg Pb Kg soil-1) in the proportions of 7.5%, 15%, and 30% (v:v). The increase of lead contamination in the soil negatively influenced the amount of carbon in the microbial biomass of the samples from both the dry and rainy seasons and the metabolic quotient only differed between the collection seasons in the 30% contaminated soil. The average value of the acid phosphatase activity in the dry season was 2.3 times higher than observed during the rainy season. There was no significant difference in the number of glomerospores observed between soils and periods studied. The most probable number of infective propagules was reduced for both seasons due to the excess lead in soil. The mycorrhizal colonization rate was reduced for the three plant species assayed. The inoculation with arbuscular mycorrhizal fungi benefited the growth of Erythrina velutina in lead contaminated soil. PMID:24031701

  18. Efficiency of modified chemical remediation techniques for soil contaminated by organochlorine pesticides

    NASA Astrophysics Data System (ADS)

    Correa-Torres, S. N.; Kopytko, M.; Avila, S.

    2016-07-01

    This study reports the optimization of innovation chemical techniques in order to improve the remediation of soils contaminated with organochloride pesticides. The techniques used for remediation were dehalogenation and chemical oxidation in soil contaminated by pesticides. These techniques were applied sequentially and combined to evaluate the design optimize the concentration and contact time variables. The soil of this study was collect in cotton crop zone in Agustin Codazzi municipality, Colombia, and its physical properties was measure. The modified dehalogenation technique of EPA was applied on the contaminated soil by adding Sodium Bicarbonate solution at different concentrations and rates during 4, 7 and 14 days, subsequently oxidation technique was implemented by applying a solution of KMnO4 at different concentration and reaction times. Organochlorine were detected by Gas Chromatography analysis coupled Mass Spectrometry and its removals were between 85.4- 90.0% of compounds such as 4, 4’-DDT, 4,4’-DDD, 4,4-DDE, trans-Clordane y Endrin. These results demonstrate that the technique of dehalogenation with oxidation chemistry can be used for remediation soils contaminated by organochloride pesticides.

  19. [Leaching Remediation of Copper and Lead Contaminated Lou Soil by Saponin Under Different Conditions].

    PubMed

    Deng, Hong-xia; Yang, Ya-li; Li, Zhen; Xu, Yan; Li, Rong-hua; Meng, Zhao-fu; Yang, Ya-ti

    2015-04-01

    In order to investigate the leaching remediation effect of the eco-friendly biosurfactant saponin for Cu and Pb in contaminated Lou soil, batch tests method was used to study the leaching effect of saponin solution on single Cu, Pb contaminated Lou soil and mixed Cu and Pb contaminated Lou soil under different conditions such as reaction time, mass concentration of saponin, pH, concentration of background electrolyte and leaching times. The results showed that the maximum leaching removal effect of Cu and Pb in contaminated Lou soil was achieved by complexation of the heavy metals with saponin micelle, when the mass concentration of saponin solution was 50 g x L(-1), pH was 5.0, the reaction time was 240 min, and there was no background electrolyte. In single and mixed contaminated Lou soil, the leaching percentages of Cu were 29.02% and 25.09% after a single leaching with 50 g x L(-1) saponin under optimal condition, while the single leaching percentages of Pb were 31.56% and 28.03%, respectively. The result indicated the removal efficiency of Pb was more significant than that of Cu. After 4 times of leaching, the cumulative leaching percentages of Cu reached 58.92% and 53.11%, while the cumulative leaching percentages of Pb reached 77.69% and 65.32% for single and mixed contaminated Lou soil, respectively. The fractionation results of heavy metals in soil before and after a single leaching showed that the contents of adsorbed and exchangeable Cu and Pb increased in the contaminated soil, while the carbonate-bound, organic bound and sulfide residual Cu and Pb in the contaminated Lou soil could be effectively removed by saponin.

  20. Experimental study of the complex resistivity and dielectric constant of chrome-contaminated soil

    NASA Astrophysics Data System (ADS)

    Liu, Haorui; Yang, Heli; Yi, Fengyan

    2016-08-01

    Heavy metals such as arsenic and chromium often contaminate soils near industrialized areas. Soil samples, made with different water content and chromate pollutant concentrations, are often needed to test soil quality. Because complex resistivity and complex dielectric characteristics of these samples need to be measured, the relationship between these measurement results and chromium concentration as well as water content was studied. Based on soil sample observations, the amplitude of the sample complex resistivity decreased with an increase of contamination concentration and water content. The phase of complex resistivity takes on a tendency of initially decrease, and then increase with the increasing of contamination concentration and water content. For a soil sample with the same resistivity, the higher the amplitude of complex resistivity, the lower the water content and the higher the contamination concentration. The real and imaginary parts of the complex dielectric constant increase with an increase in contamination concentration and water content. Note that resistivity and complex resistivity methods are necessary to adequately evaluate pollution at various sites.

  1. Processing plutonium-contaminated soil on Johnston Atoll

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Moroney, K.; Moroney, J. III; Turney, J.

    1994-07-01

    This article describes a cleanup project to process plutonium- and americium-contaminated soil on Johnston Atoll for volume reduction. Thermo Analytical`s (TMA`s) segmented gate system (SGS) for this remedial operation has been in successful on-site operation since 1992. Topics covered include the basis for development, a description of the Johnston Atoll; the significance of results; the benefits of the technology; applicability to other radiologically contaminated sites. 7 figs., 1 tab.

  2. SOLVENT EXTRACTION AND SOIL WASHING TREATMENT OF CONTAMINATED SOILS FROM WOOD PRESERVING SITES: BENCH SCALE STUDIES

    EPA Science Inventory

    Bench-scale solvent extraction and soil washing studies were performed on soil samples obtained from three abandoned wood preserving sites that included in the NPL. The soil samples from these sites were contaminated with high levels of polyaromatic hydrocarbons (PAHs), pentachlo...

  3. [Mixture Leaching Remediation Technology of Arsenic Contaminated Soil].

    PubMed

    Chen, Xun-feng; Li, Xiao-ming; Chen, Can; Yang, Qi; Deng, Lin-jing; Xie, Wei-qiang; Zhong, Yui; Huang, Bin; Yang, Wei-qiang; Zhang, Zhi-bei

    2016-03-15

    Soil contamination of arsenic pollution has become a severely environmental issue, while soil leaching is an efficient method for remediation of arsenic-contaminated soil. In this study, batch tests were primarily conducted to select optimal mixture leaching combination. Firstly, five conventional reagents were selected and combined with each other. Secondly, the fractions were analyzed before and after the tests. Finally, to explore the feasibility of mixed leaching, three soils with different arsenic pollution levels were used to compare the leaching effect. Comparing with one-step washing, the two-step sequential washing with different reagents increased the arsenic removal efficiency. These results showed that the mixture of 4 h 0.5 mol · L⁻¹ NaOH + 4 h 0.1 mol · L⁻¹ EDTA was found to be practicable, which could enhance the removal rate of arsenic from 66.67% to 91.83%, and the concentration of arsenic in soil was decreased from 186 mg · kg⁻¹ to 15.2 mg · kg⁻¹. Furthermore, the results indicated that the distribution of fractions of arsenic in soil changed apparently after mixture leaching. Leaching process could significantly reduce the available contents of arsenic in soil. Moreover, the mixture of 0.5 mol · L⁻¹ NaOH + 0.1 mol L⁻¹ EDTA could well decrease the arsenic concentration in aluminum-type soils, while the mixture of 0.5 mol · L⁻¹ OX + 0.5 mol · L⁻¹ NaOH could well decrease the arsenic concentration in iron-type soils.

  4. Chemical and microbiological characterization of an aged PCB-contaminated soil.

    PubMed

    Stella, T; Covino, S; Burianová, E; Filipová, A; Křesinová, Z; Voříšková, J; Větrovský, T; Baldrian, P; Cajthaml, T

    2015-11-15

    This study was aimed at complex characterization of three soil samples (bulk soil, topsoil and rhizosphere soil) from a site historically contaminated with polychlorinated biphenyls (PCB). The bulk soil was the most highly contaminated, with a PCB concentration of 705.95 mg kg(-1), while the rhizosphere soil was the least contaminated (169.36 mg kg(-1)). PCB degradation intermediates, namely chlorobenzoic acids (CBAs), were detected in all the soil samples, suggesting the occurrence of microbial transformation processes over time. The higher content of organic carbon in the topsoil and rhizosphere soil than in the bulk soil could be linked to the reduced bioaccessibility (bioavailability) of these chlorinated pollutants. However, different proportions of the PCB congener contents and different bioaccessibility of the PCB homologues indicate microbial biotransformation of the compounds. The higher content of organic carbon probably also promoted the growth of microorganisms, as revealed by phospholipid fatty acid (PFLA) quantification. Tag-encoded pyrosequencing analysis showed that the bacterial community structure was significantly similar among the three soils and was predominated by Proteobacteria (44-48%) in all cases. Moreover, analysis at lower taxonomic levels pointed to the presence of genera (Sphingomonas, Bulkholderia, Arthrobacter, Bacillus) including members with reported PCB removal abilities. The fungal community was mostly represented by Basidiomycota and Ascomycota, which accounted for >80% of all the sequences detected in the three soils. Fungal taxa with biodegradation potential (Paxillus, Cryptococcus, Phoma, Mortierella) were also found. These results highlight the potential of the indigenous consortia present at the site as a starting point for PCB bioremediation processes. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Activated carbon immobilizes residual polychlorinated biphenyls in weathered contaminated soil.

    PubMed

    Langlois, Valérie S; Rutter, Allison; Zeeb, Barbara A

    2011-01-01

    Activated carbon (AC) has recently been shown to be effective in sequestering persistent organic pollutants (POPs) from aquatic sediments. Most studies have demonstrated significant reductions of POP concentrations in water and in aquatic organisms; however, limited data exist on the possibility of using AC to immobilize remaining POPs at terrestrial contaminated sites. Under greenhouse conditions, pumpkin ssp cv. Howden) were grown, and red wiggler worms () were exposed to an industrial contaminated soil containing a mixture of polychlorinated biphenyls (PCBs), i.e., Aroclors 1254 and 1260) treated with one of four concentrations of AC (0.2, 0.8, 3.1, and 12.5%) for 2 mo. The addition of AC to contaminated soils virtually eliminated the bioavailability of PCBs to the plant and invertebrate species. There were reductions in PCB concentrations of more than 67% in ssp and 95% in . These data suggest that AC could be included as part of comprehensive site closure strategy at PCB-contaminated sites. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  6. Bioremediation of petroleum hydrocarbon contaminated soil by Rhodobacter sphaeroides biofertilizer and plants.

    PubMed

    Jiao, Haihua; Luo, Jinxue; Zhang, Yiming; Xu, Shengjun; Bai, Zhihui; Huang, Zhanbin

    2015-09-01

    Bio-augmentation is a promising technique for remediation of polluted soils. This study aimed to evaluate the bio-augmentation effect of Rhodobacter sphaeroides biofertilizer (RBF) on the bioremediation of total petroleum hydrocarbons (TPH) contaminated soil. A greenhouse pot experiment was conducted over a period of 120 days, three methods for enhancing bio-augmentation were tested on TPH contaminated soils, including single addition RBF, planting, and combining of RBF and three crop species, such as wheat (W), cabbage (C) and spinach (S), respectively. The results demonstrated that the best removal of TPH from contaminated soil in the RBF bio-augmentation rhizosphere soils was found to be 46.2%, 65.4%, 67.5% for W+RBF, C+RBF, S+RBF rhizosphere soils respectively. RBF supply impacted on the microbial community diversity (phospholipid fatty acids, PLFA) and the activity of soil enzymes, such as dehydrogenase (DH), alkaline phosphatase (AP) and urease (UR). There were significant difference among the soil only containing crude oil (CK), W, C and S rhizosphere soils and RBF bio-augmentation soils. Moreover, the changes were significantly distinct depended on crops species. It was concluded that the RBF is a valuable material for improving effect of remediation of TPH polluted soils.

  7. Physicochemical and biological quality of soil in hexavalent chromium-contaminated soils as affected by chemical and microbial remediation.

    PubMed

    Liao, Yingping; Min, Xiaobo; Yang, Zhihui; Chai, Liyuan; Zhang, Shujuan; Wang, Yangyang

    2014-01-01

    Chemical and microbial methods are the main remediation technologies for chromium-contaminated soil. These technologies have progressed rapidly in recent years; however, there is still a lack of methods for evaluating the chemical and biological quality of soil after different remediation technologies have been applied. In this paper, microbial remediation with indigenous bacteria and chemical remediation with ferrous sulphate were used for the remediation of soils contaminated with Cr(VI) at two levels (80 and 1,276 mg kg(-1)) through a column leaching experiment. After microbial remediation with indigenous bacteria, the average concentration of water-soluble Cr(VI) in the soils was reduced to less than 5.0 mg kg(-1). Soil quality was evaluated based on 11 soil properties and the fuzzy comprehensive assessment method, including fuzzy mathematics and correlative analysis. The chemical fertility quality index was improved by one grade using microbial remediation with indigenous bacteria, and the biological fertility quality index increased by at least a factor of 6. Chemical remediation with ferrous sulphate, however, resulted in lower levels of available phosphorus, dehydrogenase, catalase and polyphenol oxidase. The result showed that microbial remediation with indigenous bacteria was more effective for remedying Cr(VI)-contaminated soils with high pH value than chemical remediation with ferrous sulphate. In addition, the fuzzy comprehensive evaluation method was proven to be a useful tool for monitoring the quality change in chromium-contaminated soils.

  8. Assessment of soil-gas and soil contamination at the Old Metal Workshop Hog Farm Area, Fort Gordon, Georgia, 2009-2010

    USGS Publications Warehouse

    Caldwell, Andral W.; Falls, W. Fred; Guimaraes, Wladmir B.; Ratliff, W. Hagan; Wellborn, John B.; Landmeyer, James E.

    2011-01-01

    Soil gas and soil were assessed for contaminants at the Old Metal Workshop Hog Farm Area at Fort Gordon, Georgia, from October 2009 to September 2010. The assessment included delineating organic contaminants present in soil-gas and inorganic contaminants present in soil samples collected from the area estimated to be the Old Metal Workshop Hog Farm Area. This assessment was conducted to provide environmental contamination data to Fort Gordon personnel pursuant to requirements for the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. All soil-gas samplers contained total petroleum hydrocarbons above the method detection level. The highest total petroleum hydrocarbon mass detected was 121.32 micrograms in a soil-gas sampler from the western corner of the Old Metal Workshop Hog Farm Area along Sawmill Road. The highest undecane mass detected was 73.28 micrograms at the same location as the highest total petroleum hydrocarbon mass. Some soil-gas samplers detected toluene mass greater than the method detection level of 0.02 microgram; the highest detection of toluene mass was 0.07 microgram. Some soil-gas samplers were installed in areas of high-contaminant mass to assess for explosives and chemical agents. Explosives or chemical agents were not detected above their respective method detection levels for all soil-gas samplers installed. Inorganic concentrations in five soil samples collected did not exceed regional screening levels established by the U.S. Environmental Protection Agency. Barium concentrations, however, were up to eight times higher than the background concentrations reported in similar Coastal Plain sediments of South Carolina.

  9. Soil microbial community responses to antibiotic-contaminated manure under different soil moisture regimes.

    PubMed

    Reichel, Rüdiger; Radl, Viviane; Rosendahl, Ingrid; Albert, Andreas; Amelung, Wulf; Schloter, Michael; Thiele-Bruhn, Sören

    2014-01-01

    Sulfadiazine (SDZ) is an antibiotic frequently administered to livestock, and it alters microbial communities when entering soils with animal manure, but understanding the interactions of these effects to the prevailing climatic regime has eluded researchers. A climatic factor that strongly controls microbial activity is soil moisture. Here, we hypothesized that the effects of SDZ on soil microbial communities will be modulated depending on the soil moisture conditions. To test this hypothesis, we performed a 49-day fully controlled climate chamber pot experiments with soil grown with Dactylis glomerata (L.). Manure-amended pots without or with SDZ contamination were incubated under a dynamic moisture regime (DMR) with repeated drying and rewetting changes of >20 % maximum water holding capacity (WHCmax) in comparison to a control moisture regime (CMR) at an average soil moisture of 38 % WHCmax. We then monitored changes in SDZ concentration as well as in the phenotypic phospholipid fatty acid and genotypic 16S rRNA gene fragment patterns of the microbial community after 7, 20, 27, 34, and 49 days of incubation. The results showed that strongly changing water supply made SDZ accessible to mild extraction in the short term. As a result, and despite rather small SDZ effects on community structures, the PLFA-derived microbial biomass was suppressed in the SDZ-contaminated DMR soils relative to the CMR ones, indicating that dynamic moisture changes accelerate the susceptibility of the soil microbial community to antibiotics.

  10. Recent Developments for In Situ Treatment of Metal Contaminated Soils

    EPA Pesticide Factsheets

    This report assists the remedy selection process by providing information on four in situ technologies for treating soil contaminated with metals. The four approaches are electrokinetic remediation, phytoremediation, soil flushing, and...

  11. EFFECT OF SOIL MODIFYING FACTORS ON THE BIOAVAILABILITY AND TOXICITY OF METAL CONTAMINATED SOILS

    EPA Science Inventory

    Heavy metal and organic chemical contamination of soils is a worldwide problem posing a risk to humans and more directly, soil organisms. Metal toxicity is often not directly related to the total concentration of metals present due to a number of modifying factors that depend,...

  12. Overcoming phytoremediation limitations. A case study of Hg contaminated soil

    NASA Astrophysics Data System (ADS)

    Barbafieri, Meri

    2013-04-01

    Phytoremediation is a broad term that comprises several technologies to clean up water and soil. Despite the numerous articles appearing in scientific journals, very few field applications of phytoextraction have been successfully realized. The research here reported on Phytoextraction, the use the plant to "extract" metals from contaminated soil, is focused on implementations to overcome two main drawbacks: the survival of plants in unfavorable environmental conditions (contaminant toxicity, low fertility, etc.) and the often lengthy time it takes to reduce contaminants to the requested level. Moreover, to overcome the imbalance between the technology's potential and its drawbacks, there is growing interest in the use of plants to reduce only the fraction that is the most hazardous to the environment and human health, that is to target the bioavailable fractions of metals in soil. Bioavailable Contaminant Stripping (BCS) would be a remediation approach focused to remove the bioavailable metal fractions. BCS have been used in a mercury contaminated soil from Italian industrial site. Bioavailable fractions were determined by sequential extraction with H2O and NH4Cl.Combined treatments of plant hormone and thioligand to strength Hg uptake by crop plants (Brassica juncea and Helianthus annuus) were tested. Plant biomass, evapotranspiration, Hg uptake and distribution following treatments were compared. Results indicate the plant hormone, cytokinine (CK) foliar treatment, increased evapotranspiration rate in both tested plants. The Hg uptake and translocation in both tested plants increased with simultaneous addition of CK and TS treatments. B. juncea was the most effective in Hg uptake. Application of CK to plants grown in TS-treated soil lead to an increase in Hg concentration of 232% in shoots and 39% in roots with respect to control. While H. annuus gave a better response in plant biomass production, the application of CK to plants grown in TS-treated soil lead to

  13. Tannic acid for remediation of historically arsenic-contaminated soils.

    PubMed

    Gusiatin, Zygmunt Mariusz; Klik, Barbara; Kulikowska, Dorota

    2017-12-22

    Soil washing effectively and permanently decreases soil pollution. Thus, it can be considered for the removal of the most toxic elements, for example arsenic (As). In this study, historically As-contaminated soils (2041-4294 mg/kg) were remediated with tannic acid (TA) as the washing agent. The scope of this study included optimization of the operational conditions of As removal, determination of As distribution in soil before and after double soil washing, and measurement of TA loss during washing. The optimum conditions for As removal were 4% TA, pH 4 and 24 h washing time. The average As removal after single and double washings was 38% and 63%, respectively. TA decreased As content in amorphous and poorly crystalline oxides by >90%. Although TA increased the amount of As in the easily mobilizable As fraction, the stability of As in washed soils increased, with reduced partition indexes of 0.52-0.66 after washing. The maximum capacity of the soils to adsorb TA (q max ) was 50.2-70.4 g C/kg. TA sorption was higher at alkaline than at acidic conditions. Only TA removes As from soils effectively if the proportion of As in amorphous and poorly crystalline oxides is high. Thus, it can be considered for remediation of historically contaminated soils.

  14. Potential of Eucalyptus camaldulensis for phytostabilization and biomonitoring of trace-element contaminated soils

    PubMed Central

    Marañón, Teodoro; Navarro-Fernández, Carmen M.; Domínguez, María T.; Alegre, José M.; Robinson, Brett; Murillo, José M.

    2017-01-01

    Soil pollution by trace elements (TEs) from mining and industrial activity is widespread and presents a risk to humans and ecosystems. The use of trees to immobilize TEs (phytostabilization) is a low-cost and effective method of soil remediation. We aimed to determine the chemical composition of leaves and flower buds of Eucalyptus camaldulensis in seven sites along the Guadiamar River valley (SW Spain), an area contaminated by a mine-spill in 1998. E. camaldulensis trees in the spill-affected area and adjacent non affected areas were growing on a variety of soils with pH from 5.6 to 8.1 with low concentration of plant nutrients. The spill affected soils contained up to 1069 mg kg-1 of As and 4086 mg kg-1 of Pb. E. camaldulensis tolerated elevated TE concentrations in soil and, compared to other species growing in the same environment, had low TE concentrations in the aerial portions. Besides tolerance to soil contamination, E. camaldulensis had low bioaccumulation coefficients for soil contaminants. TE concentrations in the aboveground portions were below levels reported to be toxic to plants or ecosystems. Flower buds had even lower TE concentrations than leaves. Despite the relatively low concentration of TEs in leaves they were significantly correlated with the soil extractable (0.01 M CaCl2) Cd, Mn and Zn (but not Cu and Pb). The general features of this tree species: tolerance to impoverished and contaminated soils, fast growth and deep root system, and low transfer of TEs from soil to aboveground organs makes it suitable for phytostabilization of soils contaminated by TEs. In addition, eucalyptus leaves could be used for biomonitoring the soil extractability of Cd, Mn and Zn but not Cu or Pb. PMID:28666017

  15. Potential of Eucalyptus camaldulensis for phytostabilization and biomonitoring of trace-element contaminated soils.

    PubMed

    Madejón, Paula; Marañón, Teodoro; Navarro-Fernández, Carmen M; Domínguez, María T; Alegre, José M; Robinson, Brett; Murillo, José M

    2017-01-01

    Soil pollution by trace elements (TEs) from mining and industrial activity is widespread and presents a risk to humans and ecosystems. The use of trees to immobilize TEs (phytostabilization) is a low-cost and effective method of soil remediation. We aimed to determine the chemical composition of leaves and flower buds of Eucalyptus camaldulensis in seven sites along the Guadiamar River valley (SW Spain), an area contaminated by a mine-spill in 1998. E. camaldulensis trees in the spill-affected area and adjacent non affected areas were growing on a variety of soils with pH from 5.6 to 8.1 with low concentration of plant nutrients. The spill affected soils contained up to 1069 mg kg-1 of As and 4086 mg kg-1 of Pb. E. camaldulensis tolerated elevated TE concentrations in soil and, compared to other species growing in the same environment, had low TE concentrations in the aerial portions. Besides tolerance to soil contamination, E. camaldulensis had low bioaccumulation coefficients for soil contaminants. TE concentrations in the aboveground portions were below levels reported to be toxic to plants or ecosystems. Flower buds had even lower TE concentrations than leaves. Despite the relatively low concentration of TEs in leaves they were significantly correlated with the soil extractable (0.01 M CaCl2) Cd, Mn and Zn (but not Cu and Pb). The general features of this tree species: tolerance to impoverished and contaminated soils, fast growth and deep root system, and low transfer of TEs from soil to aboveground organs makes it suitable for phytostabilization of soils contaminated by TEs. In addition, eucalyptus leaves could be used for biomonitoring the soil extractability of Cd, Mn and Zn but not Cu or Pb.

  16. Indices of soil contamination by heavy metals - methodology of calculation for pollution assessment (minireview).

    PubMed

    Weissmannová, Helena Doležalová; Pavlovský, Jiří

    2017-11-07

    This article provides the assessment of heavy metal soil pollution with using the calculation of various pollution indices and contains also summarization of the sources of heavy metal soil pollution. Twenty described indices of the assessment of soil pollution consist of two groups: single indices and total complex indices of pollution or contamination with relevant classes of pollution. This minireview provides also the classification of pollution indices in terms of the complex assessment of soil quality. In addition, based on the comparison of metal concentrations in soil-selected sites of the world and used indices of pollution or contamination in soils, the concentration of heavy metal in contaminated soils varied widely, and pollution indices confirmed the significant contribution of soil pollution from anthropogenic activities mainly in urban and industrial areas.

  17. Assessment of soil-gas and soil contamination at the Patterson Anti-Tank Range, Fort Gordon, Georgia, 2009-2010

    USGS Publications Warehouse

    Caldwell, Andral W.; Falls, W. Fred; Guimaraes, Wladmir B.; Ratliff, W. Hagan; Wellborn, John B.; Landmeyer, James E.

    2011-01-01

    Soil gas and soil were assessed for contaminants at the Patterson Anti-Tank Range at Fort Gordon, Georgia, from October 2009 to September 2010. The assessment included identifying and delineating organic contaminants present in soil-gas samplers from the area estimated to be the Patterson Anti-Tank Range and in the hyporheic zone and floodplain of Brier Creek. This assessment was conducted to provide environmental contamination data to Fort Gordon personnel pursuant to requirements for the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. Soil-gas samplers in the hyporheic zone and floodplain of Brier Creek contained total petroleum hydrocarbons, benzene, octane, and pentadecane concentrations above method detection levels. All soil-gas samplers within the boundary of the Patterson Anti-Tank Range contained total petroleum hydrocarbons above the method detection level. The highest total petroleum hydrocarbon mass detected was 147.09 micrograms in a soil-gas sampler located near the middle of the site and near the remnants of a manmade earthen mound and trench. The highest toluene mass detected was 1.04 micrograms and was located in the center of the Patterson Anti-Tank Range and coincides with a manmade earthen mound. Some soil-gas samplers installed detected undecane masses greater than the method detection level of 0.04 microgram, with the highest detection of soil-gas undecane mass of 58.64 micrograms collected along the southern boundary of the site. Some soil-gas samplers were installed in areas of high-contaminant mass to assess for explosives and chemical agents. Explosives or chemical agents were not detected above their respective method detection levels for all soil-gas samplers installed.

  18. Impacts of road salts on leaching behavior of lead contaminated soil.

    PubMed

    Wu, Jingjing; Kim, Hwidong

    2017-02-15

    Research was conducted to explore the effects of road salts on lead leaching from lead contaminated soil samples that were collected in an old residence area in Erie, PA. The synthetic precipitate leaching procedure (SPLP) test was employed to evaluate lead leaching from one of the lead contaminated soils in the presence of various levels of road salts (5%, 10%, 20%, 30% and 40%). The results of the leaching test showed that lead leaching dramatically increased as the road salt content increased as a result of the formation of lead-chloride complexes, but different lead leaching patterns were observed in the presence of NaCl- and CaCl 2 -based road salts at a high content of road salts (>20%). Additional leaching tests that include 30% road salts and different soil samples showed a variety of leaching patterns by soil samples. The sequential extraction of each soil sample showed that a high fraction of organic matter bound lead was associated with lead contamination. The higher the fraction of organic matter bound lead contained in soil, the greater the effects of calcium on reducing lead leaching, observations showed. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Assessment and Comparison of Electrokinetic and Electrokinetic-bioremediation Techniques for Mercury Contaminated Soil

    NASA Astrophysics Data System (ADS)

    Azhar, A. T. S.; Nabila, A. T. A.; Nurshuhaila, M. S.; Zaidi, E.; Azim, M. A. M.; Farhana, S. M. S.

    2016-11-01

    Landfills are major sources of contamination due to the presence of harmful bacteria and heavy metals. Electrokinetic-Bioremediation (Ek-Bio) is one of the techniques that can be conducted to remediate contaminated soil. Therefore, the most prominent bacteria from landfill soil will be isolated to determine their optimal conditions for culture and growth. The degradation rate and the effectiveness of selected local bacteria were used to reduce soil contamination. Hence, this enhances microbiological activities to degrade contaminants in soil and reduce the content of heavy metals. The aim of this study is to investigate the ability of isolated bacteria (Lysinibacillus fusiformis) to remove mercury in landfill soil. 5 kg of landfill soil was mixed with deionized water to make it into slurry condition for the purpose of electrokinetic and bioremediation. This remediation technique was conducted for 7 days by using 50 V/m of electrical gradient and Lysinibacillus fusiformis bacteria was applied at the anode reservoir. The slurry landfill soil was located at the middle of the reservoir while distilled water was placed at the cathode of reservoir. After undergoing treatment for 7 days, the mercury analyzer showed that there was a significant reduction of approximately up to 78 % of mercury concentration for the landfill soil. From the results, it is proven that electrokinetic bioremediation technique is able to remove mercury within in a short period of time. Thus, a combination of Lysinibacillus fusiformis and electrokinetic technique has the potential to remove mercury from contaminated soil in Malaysia.

  20. A partition-limited model for the plant uptake of organic contaminants from soil and water

    USGS Publications Warehouse

    Chiou, C.T.; Sheng, G.; Manes, M.

    2001-01-01

    In dealing with the passive transport of organic contaminants from soils to plants (including crops), a partition-limited model is proposed in which (i) the maximum (equilibrium) concentration of a contaminant in any location in the plant is determined by partition equilibrium with its concentration in the soil interstitial water, which in turn is determined essentially by the concentration in the soil organic matter (SOM) and (ii) the extent of approach to partition equilibrium, as measured by the ratio of the contaminant concentrations in plant water and soil interstitial water, ??pt (??? 1), depends on the transport rate of the contaminant in soil water into the plant and the volume of soil water solution that is required for the plant contaminant level to reach equilibrium with the external soil-water phase. Through reasonable estimates of plant organic-water compositions and of contaminant partition coefficients with various plant components, the model accounts for calculated values of ??pt in several published crop-contamination studies, including near-equilibrium values (i.e., ??pt ??? 1) for relatively water-soluble contaminants and lower values for much less soluble contaminants; the differences are attributed to the much higher partition coefficients of the less soluble compounds between plant lipids and plant water, which necessitates much larger volumes of the plant water transport for achieving the equilibrium capacities. The model analysis indicates that for plants with high water contents the plant-water phase acts as the major reservoir for highly water-soluble contaminants. By contrast, the lipid in a plant, even at small amounts, is usually the major reservoir for highly water-insoluble contaminants.

  1. Arsenic solid-phase speciation and reversible binding in long-term contaminated soils.

    PubMed

    Rahman, M S; Clark, M W; Yee, L H; Comarmond, M J; Payne, T E; Kappen, P; Mokhber-Shahin, L

    2017-02-01

    Historic arsenic contamination of soils occurs throughout the world from mining, industrial and agricultural activities. In Australia, the control of cattle ticks using arsenicals from the late 19th to mid 20th century has led to some 1600 contaminated sites in northern New South Wales. The effect of aging in As-mobility in two dip-site soil types, ferralitic and sandy soils, are investigated utilizing isotopic exchange techniques, and synchrotron X-ray adsorption spectroscopy (XAS). Findings show that historic soil arsenic is highly bound to the soils with >90% irreversibly bound. However, freshly added As (either added to historically loaded soils or pristine soils) has a significantly higher degree of As-accessibility. XAS data indicates that historic soil arsenic is dominated as Ca- (svenekite, & weilite), Al-(mansfieldite), and Fe- (scorodite) like mineral precipitates, whereas freshly added As is dominated by mineral adsorption surfaces, particularly the iron oxy-hydroxides (goethite and hematite), but also gibbsite and kaolin surfaces. SEM data further confirmed the presence of scorodite and mansfieldite formation in the historic contaminated soils. These data suggest that aging of historic soil-As has allowed neoformational mineral recrystallisation from surface sorption processes, which greatly reduces As-mobility and accessibility. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Fusing chlorophyll fluorescence and plant canopy reflectance to detect TNT contamination in soils

    NASA Astrophysics Data System (ADS)

    Naumann, Julie C.; Rubis, Kathryn; Young, Donald R.

    2010-04-01

    TNT is released into the soil from many different sources, especially from military and mining activities, including buried land mines. Vegetation may absorb explosive residuals, causing stress and by understanding how plants respond to energetic compounds, we may be able to develop non-invasive techniques to detect soil contamination. The objectives of our study were to examine the physiological response of plants grown in TNT contaminated soils and to use remote sensing methods to detect uptake in plant leaves and canopies in both laboratory and field studies. Differences in physiology and light-adapted fluorescence were apparent in laboratory plants grown in N enriched soils and when compared with plants grown in TNT contaminated soils. Several reflectance indices were able to detect TNT contamination prior to visible signs of stress, including the fluorescence-derived indices, R740/R850 and R735/R850, which may be attributed to transformation and conjugation of TNT metabolites with other compounds. Field studies at the Duck, NC Field Research Facility revealed differences in physiological stress measures, and leaf and canopy reflectance when plants growing over suspected buried UXOs were compared with reference plants. Multiple reflectance indices indicated stress at the suspected contaminated sites, including R740/R850 and R735/R850. Under natural conditions of constant leaching of TNT into the soil, TNT uptake would be continuous in plants, potentially creating a distinct signature from remotely sensed vegetation. We may be able to use remote sensing of plant canopies to detect TNT soil contamination prior to visible signs.

  3. Pyrolytic Treatment and Fertility Enhancement of Soils Contaminated with Heavy Hydrocarbons.

    PubMed

    Vidonish, Julia E; Zygourakis, Kyriacos; Masiello, Caroline A; Gao, Xiaodong; Mathieu, Jacques; Alvarez, Pedro J J

    2016-03-01

    Pyrolysis of contaminated soils at 420 °C converted recalcitrant heavy hydrocarbons into "char" (a carbonaceous material similar to petroleum coke) and enhanced soil fertility. Pyrolytic treatment reduced total petroleum hydrocarbons (TPH) to below regulatory standards (typically <1% by weight) within 3 h using only 40-60% of the energy required for incineration at 600-1200 °C. Formation of polycyclic aromatic hydrocarbons (PAHs) was not observed, with post-pyrolysis levels well below applicable standards. Plant growth studies showed a higher biomass production of Arabidopsis thaliana and Lactuca sativa (Simpson black-seeded lettuce) (80-900% heavier) in pyrolyzed soils than in contaminated or incinerated soils. Elemental analysis showed that pyrolyzed soils contained more carbon than incinerated soils (1.4-3.2% versus 0.3-0.4%). The stark color differences between pyrolyzed and incinerated soils suggest that the carbonaceous material produced via pyrolysis was dispersed in the form of a layer coating the soil particles. Overall, these results suggest that soil pyrolysis could be a viable thermal treatment to quickly remediate soils impacted by weathered oil while improving soil fertility, potentially enhancing revegetation.

  4. Testing amendments for remediation of military range contaminated soil.

    PubMed

    Siebielec, Grzegorz; Chaney, Rufus L

    2012-10-15

    Military range soils are often strongly contaminated with metals. Information on the effectiveness of remediation of these soils is scarce. We tested the effectiveness of compost and mineral treatments for remediation and revegetation of military range soil collected in Aberdeen, MD. The soil was barren due to zinc (Zn) phytotoxicity while lead (Pb) posed a substantial risk to soil biota, wildlife and humans through various pathways. Seven treatments were tested: untreated control, agricultural NPK fertilization, high phosphate fertilization plus agricultural rates of NK, CaCO(3), "Orgro" biosolid compost, "Orgro" + CaCO(3), "Orgro" + CaCO(3) + Mn sulfate. All compost treatments alleviated Zn phytotoxicity to tall fescue; however compost combined with liming reduced plant Zn content up to 158-162 mg kg(-1). Compost added with lime reduced Pb in-vitro bioaccessibility from 32.5 to 20.4% of total Pb and was the most effective among the tested treatments. The study revealed the effectiveness of biosolids compost and lime mixture in the rapid stabilization of metals and revegetation of military range contaminated soils. The persistence of the remediation needs to be, however, confirmed in the long-term field study. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Remediation of PCB contaminated soils in the Canadian Arctic: excavation and surface PRB technology.

    PubMed

    Kalinovich, Indra; Rutter, Allison; Poland, John S; Cairns, Graham; Rowe, R Kerry

    2008-12-15

    The site BAF-5 is located on the summit of Resolution Island, Nunavut, just southeast of Baffin Island at 61 degrees 35'N and 60 degrees 40'W. The site was part of a North American military defense system established in the 1950s that became heavily contaminated with PCBs during and subsequent, its operational years. Remediation through excavation of the PCB contaminated soil at Resolution Island began in 1999 and at its completion in 2006 approximately 5 tonnes of pure PCBs in approximately 20,000 m3 of soil were remediated. Remediation strategies were based on both quantity of soil and level of contamination in the soil. Excavation removed 96% of the PCB contaminated soil on site. In 2003, a surface funnel-and-gate permeable reactive barrier was design and constructed to treat the remaining contamination left in rock crevices and inaccessible areas of the site. Excavation had destabilized contaminated soil in the area, enabling contaminant migration through erosion and runoff pathways. The barrier was designed to maximize sedimentation through settling ponds. This bulk removal enabled the treatment of highly contaminated fines and water through a permeable gate. The increased sediment loading during excavation required both modifications to the funnel and a shift to a more permeable, granular system. Granulated activated charcoal was chosen for its ability to both act as a particle retention filter and adsorptive filter. The reduction in mass of PCB and volume of soils trapped by the funnel of the barrier indicate that soils are re-stabilizing. In 2007, nonwoven geotextiles were re-introduced back into the filtration system as fine filtering could be achieved without clogging. Monitoring sites downstream indicate that the barrier system is effective. This paper describes the field progress of PCB remediation at Resolution Island.

  6. Soil biotransformation of thiodiglycol, the hydrolysis product of mustard gas: understanding the factors governing remediation of mustard gas contaminated soil.

    PubMed

    Li, Hong; Muir, Robert; McFarlane, Neil R; Soilleux, Richard J; Yu, Xiaohong; Thompson, Ian P; Jackman, Simon A

    2013-02-01

    Thiodiglycol (TDG) is both the precursor for chemical synthesis of mustard gas and the product of mustard gas hydrolysis. TDG can also react with intermediates of mustard gas degradation to form more toxic and/or persistent aggregates, or reverse the pathway of mustard gas degradation. The persistence of TDG have been observed in soils and in the groundwater at sites contaminated by mustard gas 60 years ago. The biotransformation of TDG has been demonstrated in three soils not previously exposed to the chemical. TDG biotransformation occurred via the oxidative pathway with an optimum rate at pH 8.25. In contrast with bacteria isolated from historically contaminated soil, which could degrade TDG individually, a consortium of three bacterial strains isolated from the soil never contaminated by mustard gas was able to grow on TDG in minimal medium and in hydrolysate derived from an historical mustard gas bomb. Exposure to TDG had little impacts on the soil microbial physiology or on community structure. Therefore, the persistency of TDG in soils historically contaminated by mustard gas might be attributed to the toxicity of mustard gas to microorganisms and the impact to soil chemistry during the hydrolysis. TDG biodegradation may form part of a remediation strategy for mustard gas contaminated sites, and may be enhanced by pH adjustment and aeration.

  7. Enzymatic functional stability of Zn-contaminated field-collected soils: an ecotoxicological perspective.

    PubMed

    Lessard, Isabelle; Sauvé, Sébastien; Deschênes, Louise

    2014-06-15

    Functional stability (FS) is an ecosystem attribute that is increasingly promoted in soil health assessment. However, FS is currently assessed comparatively, and it is therefore impossible to generate toxicity parameters. Additionally, the FS scores in the literature do not consider site and contamination history within the score. To address these issues, three new FS scores adapted to an ecotoxicological context and based on the Relative Soil Stability Index (RSSI) method were developed. The aim of the study was then to determine the FS score(s) that best describe the toxicity of metal-contaminated field-collected soils. Twenty pairs of Zn-contaminated soils (contaminated and reference soils) were collected on the field, and their enzymatic FS (arylsulfatase, protease, phosphatase and urease) and metal fractions (total and bioavailable) were analyzed. New RSSI-based and existing FS scores were calculated for each enzyme and correlated to the Zn fractions. One of the new RSSI-based scores was well correlated with the bioavailable labile Zn concentration for the arylsulfatase, phosphatase and urease (coefficients of regression higher than 0.50). Furthermore, this FS score was not affected by the soil organic matter and depended little on other soil properties. Other FS scores were correlated to labile Zn for only one enzyme, which varied according to the score. The new RSSI-based score thus better attributed Zn toxicity to field-collected soils than other FS scores. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

  8. Electrokinetic treatment of an agricultural soil contaminated with heavy metals.

    PubMed

    Figueroa, Arylein; Cameselle, Claudio; Gouveia, Susana; Hansen, Henrik K

    2016-07-28

    The high organic matter content in agricultural soils tends to complex and retain contaminants such as heavy metals. Electrokinetic remediation was tested in an agricultural soil contaminated with Co(+2), Zn(+2), Cd(+2), Cu(+2), Cr(VI), Pb(+2) and Hg(+2). The unenhanced electrokinetic treatment was not able to remove heavy metals from the soil due to the formation of precipitates in the alkaline environment in the soil section close to the cathode. Moreover, the interaction between metals and organic matter probably limited metal transportation under the effect of the electric field. Citric acid and ethylenediaminetetraacetic acid (EDTA) were used in the catholyte as complexing agents in order to enhance the extractability and removal of heavy metals from soil. These complexing agents formed negatively charged complexes that migrated towards the anode. The acid front electrogenerated at the anode favored the dissolution of heavy metals that were transported towards the cathode. The combined effect of the soil pH and the complexing agents resulted in the accumulation of heavy metals in the center of the soil specimen.

  9. Quality of trace element contaminated soils amended with compost under fast growing tree Paulownia fortunei plantation.

    PubMed

    Madejón, P; Xiong, J; Cabrera, F; Madejón, E

    2014-11-01

    The use of fast growing trees could be an alternative in trace element contaminated soils to stabilize these elements and improve soil quality. In this study we investigate the effect of Paulownia fortunei growth on trace element contaminated soils amended with two organic composts under semi-field conditions for a period of 18 months. The experiment was carried out in containers filled with tree different soils, two contaminated soils (neutral AZ and acid V) and a non contaminated soil, NC. Three treatments per soil were established: two organic amendments (alperujo compost, AC, and biosolid compost, BC) and a control without amendment addition. We study parameters related with fertility and contamination in soils and plants. Paulownia growth and amendments increased pH in acid soils whereas no effect of these factors was observed in neutral soils. The plant and the amendments also increased organic matter and consequently, soil fertility. Positive results were also found in soils that were only affected by plant growth (without amendment). A general improvement of "soil biochemical quality" was detected over time and treatments, confirming the positive effect of amendments plus paulownia. Even in contaminated soils, except for Cu and Zn, trace element concentrations in leaves were in the normal range for plants. Results of this mid-term study showed that Paulownia fortunei is a promising species for phytoremediation of trace element polluted soils. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. EVALUATION OF SOLIDIFICATION/STABILIZATION AS A BEST DEMONSTRATED AVAILABLE TECHNOLOGY FOR CONTAMINATED SOILS

    EPA Science Inventory

    This project involved the evaluation of solidification/stabilization technology as a BDAT for contaminated soil. Three binding agents were used on four different synthetically contaminated soils. Performance evaluation data included unconfined compressive strength (UCS) and the T...

  11. Phytoremediation of dye contaminated soil by Leucaena leucocephala (subabul) seed and growth assessment of Vigna radiata in the remediated soil

    PubMed Central

    Jayanthy, V.; Geetha, R.; Rajendran, R.; Prabhavathi, P.; Karthik Sundaram, S.; Dinesh Kumar, S.; Santhanam, P.

    2013-01-01

    The present study was investigated for soil bioremediation through sababul plant biomass (Leucaena leucocephala). The soil contaminated with textile effluent was collected from Erode (chithode) area. Various physico-chemical characterizations like N, P, and K and electrical conductivity were assessed on both control and dye contaminated soils before and after remediation. Sababul (L. leucocephala) powder used as plant biomass for remediation was a tool for textile dye removal using basic synthetic dyes by column packing and eluting. The concentration of the dye eluted was compared with its original concentration of dye and were analyzed by using UV–vis spectrophotometer. Sababul plant biomass was analyzed for its physico-chemical properties and active compounds were detected by GC–MS, HPTLC and FTIR. Plant growth was assessed with green gram on the textile contaminated soil and sababul had the potential of adsorbing the dye as the contaminated soil and also check the growth of green gram. PMID:25183943

  12. Bioleaching of arsenic in contaminated soil using metal-reducing bacteria

    NASA Astrophysics Data System (ADS)

    Lee, So-Ra; Lee, Jong-Un; Chon, Hyo-Taek

    2014-05-01

    A study on the extraction of arsenic in the contaminated soil collected from an old smelting site in Korea was carried out using metal-reducing bacteria. Two types of batch-type experiments, biostimulation and bioaugmentation, were conducted for 28 days under anaerobic conditions. The biostimulation experiments were performed through activation of indigenous bacteria by supply with glucose or lactate as a carbon source. The contaminated, autoclaved soil was inoculated with metal-reducing bacteria, Shewanella oneidensis MR-1 and S. algae BrY, in the bioaugmentation experiments. The results indicated that the maximum concentration of the extracted As was 11.2 mg/L at 4 days from the onset of the experiment when 20 mM glucose was supplied and the extraction efficiency of As ranged 60~63% in the biostimulation experiments. In the case of bioaugmentation, the highest dissolved As concentration was 24.4 mg/L at 2 days, though it dramatically decreased over time through re-adsorption onto soil particles. After both treatments, mode of As occurrence in the soil appeared to be changed to readily extractable fractions. This novel technique of bioleaching may be practically applied for remediation of As-contaminated soil after determination of optimum operational conditions such as operation time and proper carbon source and its concentration.

  13. Interactive effects of Cd and PAHs on contaminants removal from co-contaminated soil planted with hyperaccumulator plant Sedum alfredii

    USDA-ARS?s Scientific Manuscript database

    Soil contamination by multiple organic and inorganic contaminants is common but its remediation by hyperaccumulator plants is rarely reported. The growth of a cadmium (Cd) hyperaccumulator Sedum alfredii and removal of contaminants from Cd and polycyclic aromatic hydrocarbons(PAHs) co-contaminated s...

  14. Dissipation and phytoremediation of polycyclic aromatic hydrocarbons in freshly spiked and long-term field-contaminated soils.

    PubMed

    Wei, Ran; Ni, Jinzhi; Li, Xiaoyan; Chen, Weifeng; Yang, Yusheng

    2017-03-01

    Pot experiments were used to compare the dissipation and phytoremediation effect of alfalfa (Medicago sativa L.) for polycyclic aromatic hydrocarbons (PAHs) in a freshly spiked soil and two field-contaminated soils with different soil organic carbon (SOC) contents (Anthrosols, 1.41% SOC; Phaeozems, 8.51% SOC). In spiked soils, the dissipation rates of phenanthrene and pyrene were greater than 99.5 and 94.3%, respectively, in planted treatments and 95.0 and 84.5%, respectively, in unplanted treatments. In field-contaminated Anthrosols, there were limited but significant reductions of 10.2 and 15.4% of total PAHs in unplanted and planted treatments, respectively. In field-contaminated Phaeozems, there were no significant reductions of total PAHs in either unplanted or planted treatments. A phytoremediation effect was observed for the spiked soils and the Anthrosols, but not for the Phaeozems. The results indicated that laboratory tests with spiked soils cannot reflect the real state of field-contaminated soils. Phytoremediation efficiency of PAHs in field-contaminated soils was mainly determined by the content of SOC. Phytoremediation alone has no effect on the removal of PAHs in field-contaminated soils with high SOC content.

  15. Psychrotolerant bacteria for remediation of oil-contaminated soils in the Arctic

    NASA Astrophysics Data System (ADS)

    Svarovskaya, L. I.; Altunina, L. K.

    2017-12-01

    Samples of oil-contaminated peat soil are collected in the region of the Barents Sea in Arctic Kolguyev Island. A model experiment on biodegradation of polluting hydrocarbons by natural microflora exhibiting psychrophilic properties is carried out at +10°C. The geochemical activity of pure hydrocarbon-oxidizing Acinetobacter, Pseudomonas, Bacillus and Rhodococcus cultures isolated from the soil is studied at a lower temperature. The concentration of soil contamination is determined within the range 18-57 g/kg. The biodegradation of oil by natural microflora is 60% under the conditions of a model experiment.

  16. Contamination of water and soil by the Erdenet copper-molybdenum mine in Mongolia

    NASA Astrophysics Data System (ADS)

    Battogtokh, B.; Lee, J.; Woo, N. C.; Nyamjav, A.

    2013-12-01

    As one of the largest copper-molybdenum (Cu-Mo) mines in the world, the Erdenet Mine in Mongolia has been active since 1978, and is expected to continue operations for at least another 30 years. In this study, the potential impacts of mining activities on the soil and water environments have been evaluated. Water samples showed high concentrations of sulfate, calcium, magnesium, Mo, and arsenic, and high pH values in the order of high to low as follows: tailing water > Khangal River > groundwater. Statistical analysis and the δ2H and δ18O values of water samples indicate that the tailing water directly affects the stream water and indirectly affects groundwater through recharge processes. Soil and stream sediments are highly contaminated with Cu and Mo, which are major elements of ore minerals. Based on the contamination factor (CF), the pollution load index (PLI), and the degree of contamination (Cd), soil appears to be less contaminated than stream sediments. The soil particle size is similar to that of tailing materials, but stream sediments have much coarser particles, implying that the materials have different origins. Contamination levels in stream sediments display a tendency to decrease with distance from the mine, but no such changes are found in soil. Consequently, soil contamination by metals is attributable to wind-blown dusts from the tailing materials, and stream sediment contamination is caused by discharges from uncontained subgrade ore stock materials. Considering the evident impact on the soil and water environment, and the human health risk from the Erdenet Mine, measures to mitigate its environmental impact should be taken immediately including source control, the establishment of a systematic and continuous monitoring system, and a comprehensive risk assessment. Sampling locations around the Erdenet Mine

  17. Analysis of Pollution Hazard Intensity: A Spatial Epidemiology Case Study of Soil Pb Contamination.

    PubMed

    Ha, Hoehun; Rogerson, Peter A; Olson, James R; Han, Daikwon; Bian, Ling; Shao, Wanyun

    2016-09-14

    Heavy industrialization has resulted in the contamination of soil by metals from anthropogenic sources in Anniston, Alabama. This situation calls for increased public awareness of the soil contamination issue and better knowledge of the main factors contributing to the potential sources contaminating residential soil. The purpose of this spatial epidemiology research is to describe the effects of physical factors on the concentration of lead (Pb) in soil in Anniston AL, and to determine the socioeconomic and demographic characteristics of those residing in areas with higher soil contamination. Spatial regression models are used to account for spatial dependencies using these explanatory variables. After accounting for covariates and multicollinearity, results of the analysis indicate that lead concentration in soils varies markedly in the vicinity of a specific foundry (Foundry A), and that proximity to railroads explained a significant amount of spatial variation in soil lead concentration. Moreover, elevated soil lead levels were identified as a concern in industrial sites, neighborhoods with a high density of old housing, a high percentage of African American population, and a low percent of occupied housing units. The use of spatial modelling allows for better identification of significant factors that are correlated with soil lead concentrations.

  18. Effects of the inoculant strain Sphingomonas paucimobilis 20006FA on soil bacterial community and biodegradation in phenanthrene-contaminated soil.

    PubMed

    Coppotelli, B M; Ibarrolaza, A; Del Panno, M T; Morelli, I S

    2008-02-01

    The effects of the inoculant strain Sphingomonas paucimobilis 20006FA (isolated from a phenanthrene-contaminated soil) on the dynamics and structure of microbial communities and phenanthrene elimination rate were studied in soil microcosms artificially contaminated with phenanthrene. The inoculant managed to be established from the first inoculation as it was evidenced by denaturing gradient gel electrophoresis analysis, increasing the number of cultivable heterotrophic and PAH-degrading cells and enhancing phenanthrene degradation. These effects were observed only during the inoculation period. Nevertheless, the soil biological activity (dehydrogenase activity and CO(2) production) showed a late increase. Whereas gradual and successive changes in bacterial community structures were caused by phenanthrene contamination, the inoculation provoked immediate, significant, and stable changes on soil bacterial community. In spite of the long-term establishment of the inoculated strain, at the end of the experiment, the bioaugmentation did not produce significant changes in the residual soil phenanthrene concentration and did not improve the residual effects on the microbial soil community.

  19. Treatability of volatile chlorinated hydrocarbon-contaminated soils of different textures along a vertical profile by mechanical soil aeration: A laboratory test.

    PubMed

    Ma, Yan; Shi, Yi; Hou, Deyi; Zhang, Xi; Chen, Jiaqi; Wang, Zhifen; Xu, Zhu; Li, Fasheng; Du, Xiaoming

    2017-04-01

    Mechanical soil aeration is a simple, effective, and low-cost soil remediation technology that is suitable for sites contaminated with volatile chlorinated hydrocarbons (VCHs). Conventionally, this technique is used to treat the mixed soil of a site without considering the diversity and treatability of different soils within the site. A laboratory test was conducted to evaluate the effectiveness of mechanical soil aeration for remediating soils of different textures (silty, clayey, and sandy soils) along a vertical profile at an abandoned chloro-alkali chemical site in China. The collected soils were artificially contaminated with chloroform (TCM) and trichloroethylene (TCE). Mechanical soil aeration was effective for remediating VCHs (removal efficiency >98%). The volatilization process was described by an exponential kinetic function. In the early stage of treatment (0-7hr), rapid contaminant volatilization followed a pseudo-first order kinetic model. VCH concentrations decreased to low levels and showed a tailing phenomenon with very slow contaminant release after 8hr. Compared with silty and sandy soils, clayey soil has high organic-matter content, a large specific surface area, a high clay fraction, and a complex pore structure. These characteristics substantially influenced the removal process, making it less efficient, more time consuming, and consequently more expensive. Our findings provide a potential basis for optimizing soil remediation strategy in a cost-effective manner. Copyright © 2016. Published by Elsevier B.V.

  20. Phyotoxicity of diesel soil contamination on the germination of Lactuca sativa and Ipomoea batatas.

    PubMed

    Fatokun, Kayode; Lewu, Francis Bayo; Zharare, Godfrey Elijah

    2015-11-01

    Phytotoxic effect of diesel contaminated soil on germination rate of Lactuca sativa and Ipomoea batatas, at two concentrations ranges (0-6ml and 0-30ml), were investigated and compared. Diesel soil contamination was simulated and soil samples were taken from contaminated soil at 1, 5,10, 15, 25, 50, 75 and 100 days should be after planting. The result showed that in both plant species, diesel inhibited germination in a concentration dependent manner, Also, the influence of diesel contamination diminished with increased time duration; suggesting possible reduction in diesel toxicity over time. However, germination of lettuce was significant and negatively correlated (r2 = -0.941) with diesel contamination as compared to sweet potato (r2 = -0.638).Critical concentration of diesel in relation to seed germination of L. sativa was lower than vegetative germination of I. batatas, indicating that germination of I. batatas was less sensitive to diesel contamination as compared to L. sativa.

  1. Utilization of grasses for potential biofuel production and phytoremediation of heavy metal contaminated soils.

    PubMed

    Balsamo, Ronald A; Kelly, William J; Satrio, Justinus A; Ruiz-Felix, M Nydia; Fetterman, Marisa; Wynn, Rodd; Hagel, Kristen

    2015-01-01

    This research focuses on investigating the use of common biofuel grasses to assess their potential as agents of long-term remediation of contaminated soils using lead as a model heavy metal ion. We present evidence demonstrating that switch grass and Timothy grass may be potentially useful for long-term phytoremediation of heavy metal contaminated soils and describe novel techniques to track and remove contaminants from inception to useful product. Enzymatic digestion and thermochemical approaches are being used to convert this lignocellulosic feedstock into useful product (sugars, ethanol, biocrude oil+biochar). Preliminary studies on enzymatic hydrolysis and fast pyrolysis of the Switchgrass materials that were grown in heavy metal contaminated soil and non-contaminated soils show that the presence of lead in the Switchgrass material feedstock does not adversely affect the outcomes of the conversion processes. These results indicate that the modest levels of contaminant uptake allow these grass species to serve as phytoremediation agents as well as feedstocks for biofuel production in areas degraded by industrial pollution.

  2. Surfactant flushing remediation of o-dichlorobenzene and p-dichlorobenzene contaminated soil.

    PubMed

    Pei, Guangpeng; Zhu, Yuen; Cai, Xiatong; Shi, Weiyu; Li, Hua

    2017-10-01

    Surfactant-enhanced remediation is used to treat dichlorobenzene (DCB) contaminated soil. In this study, soil column experiments were conducted to investigate the removal efficiencies of o-dichlorobenzene (o-DCB) and p-dichlorobenzene (p-DCB) from contaminated soil using micellar solutions of biosurfactants (saponin, alkyl polyglycoside) compare to a chemically synthetic surfactant (Tween 80). Leachate was collected and analyzed for o-DCB and p-DCB content. In addition, soil was analyzed to explore the effect of surfactants on soil enzyme activities. Results showed that the removal efficiency of o-DCB and p-DCB was highest for saponin followed by alkyl polyglycoside and Tween 80. The maximum o-DCB and p-DCB removal efficiencies of 76.34% and 80.43%, respectively, were achieved with 4 g L -1 saponin solution. However, an opposite result was observed in the cumulative mass of o-DCB and p-DCB in leachate. The cumulative extent of o-DCB and p-DCB removal by the biosurfactants saponin and alkyl polyglycoside was lower than that of the chemically synthetic surfactant Tween 80 in leachate. Soil was also analyzed to explore the effect of surfactants on soil enzyme activities. The results indicated that surfactants were potentially effective in facilitating soil enzyme activities. Thus, it was confirmed that the biosurfactants saponin and alkyl polyglycoside could be used for remediation of o-DCB and p-DCB contaminated soil. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Mouse Assay for Determination of Arsenic Bioavailability in Contaminated Soils

    EPA Science Inventory

    Background: Accurate assessment of human exposure estimates from arsenic-contaminated soils depends upon estimating arsenic (As) soil bioavailability. Development of bioavailability assays provides data needed for human health risk assessments and supports development and valida...

  4. Impacts of soil petroleum contamination on nutrient release during litter decomposition of Hippophae rhamnoides.

    PubMed

    Zhang, Xiaoxi; Liu, Zengwen; Luc, Nhu Trung; Yu, Qi; Liu, Xiaobo; Liang, Xiao

    2016-03-01

    Petroleum exploitation causes contamination of shrub lands close to oil wells. Soil petroleum contamination affects nutrient release during the litter decomposition of shrubs, which influences nutrient recycling and the maintenance of soil fertility. Hence, this contamination may reduce the long-term growth and stability of shrub communities and consequently, the effects of phytoremediation. Fresh foliar litter of Hippophae rhamnoides, a potential phytoremediating species, was collected for this study. The litter was placed in litterbags and then buried in different petroleum-polluted soil media (the petroleum concentrations were 15, 30, and 45 g kg(-1) dry soil, which were considered as slightly, moderately and seriously polluted soil, respectively) for a decomposition test. The impacts of petroleum contamination on the release of nutrients (including N, P, K, Cu, Zn, Fe, Mn, Ca and Mg) were assessed. The results showed that (1) after one year of decomposition, the release of all nutrients was accelerated in the slightly polluted soil. In the moderately polluted soil, P release was accelerated, while Cu, Zn and Mn release was inhibited. In the seriously polluted soil, Cu and Zn release was accelerated, while the release of the other nutrients was inhibited. (2) The effect of petroleum on nutrient release from litter differed in different periods during decomposition; this was mainly due to changes in soil microorganisms and enzymes under the stress of petroleum contamination. (3) To maintain the nutrient cycling and the soil fertility of shrub lands, H. rhamnoides is only suitable for phytoremediation of soils containing less than 30 g kg(-1) of petroleum.

  5. Rapid identification of oil-contaminated soils using visible near-infrared diffuse reflectance spectroscopy.

    PubMed

    Chakraborty, Somsubhra; Weindorf, David C; Morgan, Cristine L S; Ge, Yufeng; Galbraith, John M; Li, Bin; Kahlon, Charanjit S

    2010-01-01

    In the United States, petroleum extraction, refinement, and transportation present countless opportunities for spillage mishaps. A method for rapid field appraisal and mapping of petroleum hydrocarbon-contaminated soils for environmental cleanup purposes would be useful. Visible near-infrared (VisNIR, 350-2500 nm) diffuse reflectance spectroscopy (DRS) is a rapid, nondestructive, proximal-sensing technique that has proven adept at quantifying soil properties in situ. The objective of this study was to determine the prediction accuracy of VisNIR DRS in quantifying petroleum hydrocarbons in contaminated soils. Forty-six soil samples (including both contaminated and reference samples) were collected from six different parishes in Louisiana. Each soil sample was scanned using VisNIR DRS at three combinations of moisture content and pretreatment: (i) field-moist intact aggregates, (ii) air-dried intact aggregates, (iii) and air-dried ground soil (sieved through a 2-mm sieve). The VisNIR spectra of soil samples were used to predict total petroleum hydrocarbon (TPH) content in the soil using partial least squares (PLS) regression and boosted regression tree (BRT) models. Each model was validated with 30% of the samples that were randomly selected and not used in the calibration model. The field-moist intact scan proved best for predicting TPH content with a validation r2 of 0.64 and relative percent difference (RPD) of 1.70. Because VisNIR DRS was promising for rapidly predicting soil petroleum hydrocarbon content, future research is warranted to evaluate the methodology for identifying petroleum contaminated soils.

  6. Soil matrix tracer contamination and canopy recycling did not impair ¹³CO₂ plant-soil pulse labelling experiments.

    PubMed

    Barthel, Matthias; Sturm, Patrick; Knohl, Alexander

    2011-09-01

    When conducting (13)CO(2) plant-soil pulse labelling experiments, tracer material might cause unwanted side effects which potentially affect δ(13)C measurements of soil respiration (δ(13)C(SR)) and the subsequent data interpretation. First, when the soil matrix is not isolated from the atmosphere, contamination of the soil matrix with tracer material occurs leading to a physical back-diffusion from soil pores. Second, when using canopy chambers continuously, (13)CO(2) is permanently re-introduced into the atmosphere due to leaf respiration which then aids re-assimilation of tracer material by the canopy. Accordingly, two climate chamber experiments on European beech saplings (Fagus sylvatica L.) were conducted to evaluate the influence of soil matrix (13)CO(2) contamination and canopy recycling on soil (13)CO(2) efflux during (13)CO(2) plant-soil pulse labelling experiments. For this purpose, a combined soil/canopy chamber system was developed which separates soil and canopy compartments in order to (a) prevent diffusion of (13)C tracer into the soil chamber during a (13)CO(2) canopy pulse labelling and (b) study stable isotope processes in soil and canopy individually and independently. In combination with laser spectrometry measuring CO(2) isotopologue mixing ratios at a rate of 1 Hz, we were able to measure δ(13)C in canopy and soil at very high temporal resolution. For the soil matrix contamination experiment, (13)CO(2) was applied to bare soil, canopy only or, simultaneously, to soil and canopy of the beech trees. The obtained δ(13)C(SR) fluxes from the different treatments were then compared with respect to label re-appearance, first peak time and magnitude. By determining the δ(13)C(SR) decay of physical (13)CO(2) back-diffusion from bare soils (contamination), it was possible to separate biological and physical components in δ(13)C(SR) of a combined flux of both. A second pulse labelling experiment, with chambers permanently enclosing the canopy

  7. Potential of Ranunculus acris L. for biomonitoring trace element contamination of riverbank soils: photosystem II activity and phenotypic responses for two soil series.

    PubMed

    Marchand, Lilian; Lamy, Pierre; Bert, Valerie; Quintela-Sabaris, Celestino; Mench, Michel

    2016-02-01

    Foliar ionome, photosystem II activity, and leaf growth parameters of Ranunculus acris L., a potential biomonitor of trace element (TE) contamination and phytoavailability, were assessed using two riverbank soil series. R. acris was cultivated on two potted soil series obtained by mixing a TE (Cd, Cu, Pb, and Zn)-contaminated technosol with either an uncontaminated sandy riverbank soil (A) or a silty clay one slightly contaminated by TE (B). Trace elements concentrations in the soil-pore water and the leaves, leaf dry weight (DW) yield, total leaf area (TLA), specific leaf area (SLA), and photosystem II activity were measured for both soil series after a 50-day growth period. As soil contamination increased, changes in soluble TE concentrations depended on soil texture. Increase in total soil TE did not affect the leaf DW yield, the TLA, the SLA, and the photosystem II activity of R. acris over the 50-day exposure. The foliar ionome did not reflect the total and soluble TE concentrations in both soil series. Foliar ionome of R. acris was only effective to biomonitor total and soluble soil Na concentrations in both soil series and total and soluble soil Mo concentrations in the soil series B.

  8. Three-dimensional data interpolation for environmental purpose: lead in contaminated soils in southern Brazil.

    PubMed

    Piedade, Tales Campos; Melo, Vander Freitas; Souza, Luiz Cláudio Paula; Dieckow, Jeferson

    2014-09-01

    Monitoring of heavy metal contamination plume in soils can be helpful in establishing strategies to minimize its hazardous impacts to the environment. The objective of this study was to apply a new approach of visualization, based on tridimensional (3D) images, of pseudo-total (extracted with concentrated acids) and exchangeable (extracted with 0.5 mol L(-1) Ca(NO3)2) lead (Pb) concentrations in soils of a mining and metallurgy area to determine the spatial distribution of this pollutant and to estimate the most contaminated soil volumes. Tridimensional images were obtained after interpolation of Pb concentrations of 171 soil samples (57 points × 3 depths) with regularized spline with tension in a 3D function version. The tridimensional visualization showed great potential of use in environmental studies and allowed to determine the spatial 3D distribution of Pb contamination plume in the area and to establish relationships with soil characteristics, landscape, and pollution sources. The most contaminated soil volumes (10,001 to 52,000 mg Pb kg(-1)) occurred near the metallurgy factory. The main contamination sources were attributed to atmospheric emissions of particulate Pb through chimneys. The large soil volume estimated to be removed to industrial landfills or co-processing evidenced the difficulties related to this practice as a remediation strategy.

  9. [Parameters optimization and cleaning efficiency evaluation of attrition scrubbing remediation of Pb-contaminated soil].

    PubMed

    Yang, Wen; Huang, Jin-lou; Peng, Hui-qing; Li, Si-tuo

    2013-09-01

    Attrition scrubbing was used to remediate lead contaminated-site soil, and the main purpose was to remove fine particles and lead contaminants from the surface of sand. The optimal parameters of attrition scrubbing were determined by orthogonal experiment, and three soil samples with different lead concentration were subjected to attrition scrubbing experiments. The results showed that the optimal scrubbing parameters were: a solid ratio of 70% dry matter, a temperature of 25 degrees C, an attrition time of 30 min, and an attrition speed of 1200 r x min(-1). Before attrition scrubbing, the screening and analysis of soil showed that in all three soil samples, lead was mainly enriched on sand and fine particles, and the distribution of lead was highly correlated to the organic matter. After attrition scrubbing, the washing efficiency of the original state lead contaminated sand soil in triplicates was 67.61%, 31.71% and 41.01%, respectively, which indicates that attrition scrubbing can remove part of the fine soil and lead contaminants from the surface of sand, to accomplish the purpose of pollutants enrichment. Scanning electron microscopy (SEM) analysis showed that the sand surface became smooth after attrition scrubbing. The results above show that attrition scrubbing has a good washing effect for the remediation of lead contaminated sand soil.

  10. Ex situ bioremediation of oil-contaminated soil.

    PubMed

    Lin, Ta-Chen; Pan, Po-Tsen; Cheng, Sheng-Shung

    2010-04-15

    An innovative bioprocess method, Systematic Environmental Molecular Bioremediation Technology (SEMBT) that combines bioaugmentation and biostimulation with a molecular monitoring microarray biochip, was developed as an integrated bioremediation technology to treat S- and T-series biopiles by using the landfarming operation and reseeding process to enhance the bioremediation efficiency. After 28 days of the bioremediation process, diesel oil (TPH(C10-C28)) and fuel oil (TPH(C10-C40)) were degraded up to approximately 70% and 63% respectively in the S-series biopiles. When the bioaugmentation and biostimulation were applied in the beginning of bioremediation, the microbial concentration increased from approximately 10(5) to 10(6) CFU/g dry soil along with the TPH biodegradation. Analysis of microbial diversity in the contaminated soils by microarray biochips revealed that Acinetobacter sp. and Pseudomonas aeruginosa were the predominant groups in indigenous consortia, while the augmented consortia were Gordonia alkanivorans and Rhodococcus erythropolis in both series of biopiles during bioremediation. Microbial respiration as influenced by the microbial activity reflected directly the active microbial population and indirectly the biodegradation of TPH. Field experimental results showed that the residual TPH concentration in the complex biopile was reduced to less than 500 mg TPH/kg dry soil. The above results demonstrated that the SEMBT technology is a feasible alternative to bioremediate the oil-contaminated soil. Crown Copyright 2009. Published by Elsevier B.V. All rights reserved.

  11. Combination of microbial oxidation and biogenic schwertmannite immobilization: A potential remediation for highly arsenic-contaminated soil.

    PubMed

    Yang, Zhihui; Wu, Zijian; Liao, Yingping; Liao, Qi; Yang, Weichun; Chai, Liyuan

    2017-08-01

    Here, a novel strategy that combines microbial oxidation by As(III)-oxidizing bacterium and biogenic schwertmannite (Bio-SCH) immobilization was first proposed and applied for treating the highly arsenic-contaminated soil. Brevibacterium sp. YZ-1 isolated from a highly As-contaminated soil was used to oxidize As(III) in contaminated soils. Under optimum culture condition for microbial oxidation, 92.3% of water-soluble As(III) and 84.4% of NaHCO 3 -extractable As(III) in soils were removed. Bio-SCH synthesized through the oxidation of ferrous sulfate by Acidithiobacillus ferrooxidans immobilize As(V) in the contaminated soil effectively. Consequently, the combination of microbial oxidation and Bio-SCH immobilization performed better in treating the highly As-contaminated soil with immobilization efficiencies of 99.3% and 82.6% for water-soluble and NaHCO 3 -extractable total As, respectively. Thus, the combination can be considered as a green remediation strategy for developing a novel and valuable solution for As-contaminated soils. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Advanced remediation of uranium-contaminated soil.

    PubMed

    Kim, S S; Han, G S; Kim, G N; Koo, D S; Kim, I G; Choi, J W

    2016-11-01

    The existing decontamination method using electrokinetic equipment after acidic washing for uranium-contaminated soil requires a long decontamination time and a significant amount of electric power. However, after soil washing, with a sulfuric acid solution and an oxidant at 65 °C, the removal of the muddy solution using a 100 mesh sieve can decrease the radioactivity of the remaining coarse soil to the clearance level. Therefore, only a small amount of fine soil collected from the muddy solution requires the electrokinetic process for its decontamination. Furthermore, it is found that the selective removal of uranium from the sulfuric washing solution is not obtained using an anion exchanger but rather using a cation exchanger, unexpectedly. More than 90% of the uranium in the soil washing solutions is adsorbed on the S-950 resin, and 87% of the uranium adsorbed on S-950 is desorbed by washing with a 0.5 M Na 2 CO 3 solution at 60 °C. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Zinc fractionation in contaminated soils by sequential and single extractions: influence of soil properties and zinc content.

    PubMed

    Voegelin, Andreas; Tokpa, Gerome; Jacquat, Olivier; Barmettler, Kurt; Kretzschmar, Ruben

    2008-01-01

    We studied the fractionation of zinc (Zn) in 49 contaminated soils as influenced by Zn content and soil properties using a seven-step sequential extraction procedure (F1: NH4NO3; F2: NH4-acetate, pH 6; F3: NH3OHCl, pH 6; F4: NH4-EDTA, pH 4.6; F5: NH4-oxalate, pH 3; F6: NH4-oxalate/ascorbic acid, pH 3; F7: residual). The soils had developed from different geologic materials and covered a wide range in soil pH (4.0-7.3), organic C content (9.3-102 g kg(-1)), and clay content (38-451 g kg(-1)). Input of aqueous Zn with runoff water from electricity towers during 26 to 74 yr resulted in total soil Zn contents of 3.8 to 460 mmol kg(-1). In acidic soils (n = 24; pH <6.0), Zn was mainly found in the mobile fraction (F1) and the last two fractions (F6 and F7). In neutral soils (n = 25; pH > or =6.0), most Zn was extracted in the mobilizable fraction (F2) and the intermediate fractions (F4 and F5). The extractability of Zn increased with increasing Zn contamination of the soils. The sum of mobile (F1) and mobilizable (F2) Zn was independent of soil pH, the ratio of Zn in F1 over F1+F2 plotted against soil pH, exhibited the typical shape of a pH sorption edge and markedly increased from pH 6 to pH 5, reflecting the increasing lability of mobilizable Zn with decreasing soil pH. In conclusion, the extractability of Zn from soils contaminated with aqueous Zn after decades of aging under field conditions systematically varied with soil pH and Zn content. The same trends are expected to apply to aqueous Zn released from decomposing Zn-bearing contaminants, such as sewage sludge or smelter slag. The systematic trends in Zn fractionation with varying soil pH and Zn content indicate the paramount effect of these two factors on molecular scale Zn speciation. Further research is required to characterize the link between the fractionation and speciation of Zn and to determine how Zn loading and soil physicochemical properties affect Zn speciation in soils.

  14. Assessing the Educational Needs of Urban Gardeners and Farmers on the Subject of Soil Contamination

    ERIC Educational Resources Information Center

    Harms, Ashley Marie Raes; Presley, DeAnn Ricks; Hettiarachchi, Ganga M.; Thien, Stephen J.

    2013-01-01

    Participation in urban agriculture is growing throughout the United States; however, potential soil contaminants in urban environments present challenges. Individuals in direct contact with urban soil should be aware of urban soil quality and soil contamination issues to minimize environmental and human health risks. The study reported here…

  15. Impact of Long-Term Diesel Contamination on Soil Microbial Community Structure

    PubMed Central

    Maphosa, Farai; Morillo, Jose A.; Abu Al-Soud, Waleed; Langenhoff, Alette A. M.; Grotenhuis, Tim; Rijnaarts, Huub H. M.; Smidt, Hauke

    2013-01-01

    Microbial community composition and diversity at a diesel-contaminated railway site were investigated by pyrosequencing of bacterial and archaeal 16S rRNA gene fragments to understand the interrelationships among microbial community composition, pollution level, and soil geochemical and physical properties. To this end, 26 soil samples from four matrix types with various geochemical characteristics and contaminant concentrations were investigated. The presence of diesel contamination significantly impacted microbial community composition and diversity, regardless of the soil matrix type. Clean samples showed higher diversity than contaminated samples (P < 0.001). Bacterial phyla with high relative abundances in all samples included Proteobacteria, Firmicutes, Actinobacteria, Acidobacteria, and Chloroflexi. High relative abundances of Archaea, specifically of the phylum Euryarchaeota, were observed in contaminated samples. Redundancy analysis indicated that increased relative abundances of the phyla Chloroflexi, Firmicutes, and Euryarchaeota correlated with the presence of contamination. Shifts in the chemical composition of diesel constituents across the site and the abundance of specific operational taxonomic units (OTUs; defined using a 97% sequence identity threshold) in contaminated samples together suggest that natural attenuation of contamination has occurred. OTUs with sequence similarity to strictly anaerobic Anaerolineae within the Chloroflexi, as well as to Methanosaeta of the phylum Euryarchaeota, were detected. Anaerolineae and Methanosaeta are known to be associated with anaerobic degradation of oil-related compounds; therefore, their presence suggests that natural attenuation has occurred under anoxic conditions. This research underscores the usefulness of next-generation sequencing techniques both to understand the ecological impact of contamination and to identify potential molecular proxies for detection of natural attenuation. PMID:23144139

  16. The effect on performance and biochemical parameters when soil was added to aflatoxin-contaminated poultry rations.

    PubMed

    Madden, U A; Stahr, H M; Stino, F K

    1999-08-01

    The effects of silty clay loam soil on the performance and biochemical parameters of chicks were investigated when the soil was added to aflatoxin B1 (AFB1)-contaminated diets. One hundred 14-d-old White Leghorn chicks were fed a control ration (clean corn), a low aflatoxin-contaminated ration (120 ng AFB1/g), a high aflatoxin-contaminated ration (700 ng AFB1/g), or high aflatoxin-contaminated rations (700 ng AFB1/g) +10% or 25% soil. Body weight, feed consumption and blood samples were monitored weekly. Decreased feed consumption, body weight gain and efficiency of feed utilization, increased SGOT and LDH activities, and cholesterol and triglyceride concentrations, and decreased uric acid concentrations and ALP activity were observed in the chicks fed the high aflatoxin-contaminated ration without soil. Hepatomegaly was prominent in chicks fed the high aflatoxin-contaminated ration without soil, and some livers had extensive hepatocyte vacuolation, hepatocellular swelling, fatty change and hydropic degeneration, and stained positive for fat accumulation. Addition of soil reduced the detrimental effects of AFB1 for some parameters, although the reduction was less when 10% soil was fed compared with the 25% soil feeding.

  17. Review on utilization of biochar for metal-contaminated soil and sediment remediation.

    PubMed

    Wang, Mingming; Zhu, Yi; Cheng, Lirong; Andserson, Bruce; Zhao, Xiaohui; Wang, Dayang; Ding, Aizhong

    2018-01-01

    Biochar is a carbon-neutral or even carbon-negative material produced through thermal decomposition of plant- and animal-based biomass under oxygen-limited conditions. Recently, there has been an increasing interest in the application of biochar as an adsorbent, soil ameliorant and climate mitigation approach in many types of applications. Metal-contaminated soil remediation using biochar has been intensively investigated in small-scale and pilot-scale trials with obtained beneficial results and multifaceted effects. But so far, the study and application of biochar in contaminated sediment management has been very limited, and this is also a worldwide problem. Nonetheless, there is reason to believe that the same multiple benefits can also be realized with these sediments due to similar mechanisms for stabilizing contaminants. This paper provides a review on current biochar properties and its use as a sorbent/amendment for metal-contaminated soil/sediment remediation and its effect on plant growth, fauna habits as well as microorganism communities. In addition, the use of biochar as a potential strategy for contaminated sediment management is also discussed, especially as regards in-situ planning. Finally, we highlight the possibility of biochar application as an effective amendment and propose further research directions to ensure the safe and sustainable use of biochar as an amendment for remediation of contaminated soil and sediment. Copyright © 2017. Published by Elsevier B.V.

  18. Deciphering biodegradable chelant-enhanced phytoremediation through microbes and nitrogen transformation in contaminated soils.

    PubMed

    Fang, Linchuan; Wang, Mengke; Cai, Lin; Cang, Long

    2017-06-01

    Biodegradable chelant-enhanced phytoremediation offers an alternative treatment technique for metal contaminated soils, but most studies to date have addressed on phytoextraction efficiency rather than comprehensive understanding of the interactions among plant, soil microbes, and biodegradable chelants. In the present study, we investigated the impacts of biodegradable chelants, including nitrilotriacetate, S,S-ethylenediaminedisuccinic acid (EDDS), and citric acid on soil microbes, nitrogen transformation, and metal removal from contaminated soils. The EDDS addition to soil showed the strongest ability to promote the nitrogen cycling in soil, ryegrass tissue, and microbial metabolism in comparison with other chelants. Both bacterial community-level physiological profiles and soil mass specific heat rates demonstrated that soil microbial activity was inhibited after the EDDS application (between day 2 and 10), but this effect completely vanished on day 30, indicating the revitalization of microbial activity and community structure in the soil system. The results of quantitative real-time PCR revealed that the EDDS application stimulated denitrification in soil by increasing nitrite reductase genes, especially nirS. These new findings demonstrated that the nitrogen release capacity of biodegradable chelants plays an important role in accelerating nitrogen transformation, enhancing soil microbial structure and activity, and improving phytoextraction efficiency in contaminated soil.

  19. Phytoremediation of Metal-Contaminated Soil for Improving Food Safety

    NASA Astrophysics Data System (ADS)

    Shilev, Stefan; Benlloch, Manuel; Dios-Palomares, R.; Sancho, Enrique D.

    The contamination of the environment is a serious problem which provokes great interest in our society and in the whole scientific community. The input of metals into soils has increased during the last few decades as a consequence of different human activities (storage of industrial and municipal wastes, burning of fuels, mining and wastewater treatments, functioning of non-ferrous-metal-producing smelters, etc.). Nowadays, this type of contamination is one of the most serious concerning the chronic toxic effect which it renders on human health and the environment. As a consequence of all these activities, a huge number of toxic metals and metalloids, such as Cu, Zn, Pb, Cd, Hg and As, among many others, have been accumulated in soils, reaching toxic values. Unfortunately, much contaminated land is still in use for crop production, despite the danger that the metal content poses.

  20. Reclamation of Cr-contaminated or Cu-contaminated agricultural soils using sunflower and chelants.

    PubMed

    Cicatelli, Angela; Guarino, Francesco; Castiglione, Stefano

    2017-04-01

    Chromium (Cr) and copper (Cu) are pollutants with a strong environmental impact. "Green biotechnology" as phytoremediation represents a sustainability opportunity for soil reclamation. In this study, we evaluated the possibility to reclaim agricultural soils located in the Solofrana valley, contaminated by Cr or Cu. Chromium contamination derives by repeated flooding events of Solofrana rivers containing Cr because of leather tanning plants, while Cu soil pollution was due to the use of Cu-rich pesticides in agriculture. Both metals showed a very low bioavailability. In order to perform an assisted phytoremediation of polluted fields, we carried out a preliminary ex situ experimentation testing for the first time sunflowers (cv. Pretor) and chelants (ethylenediaminetetraacetic acid (EDTA) and/or ethylene diamine disuccinate (EDDS)), useful when metal bioavailability is low. No symptoms of toxicity were observed in sunflowers grown on both soils, while biomass was improved when EDDS was added. Cr and Cu bioavailability was only slightly enhanced by chelants at the end of the treatments. Both Cr and Cu were mainly accumulated in the roots; moreover, Cu was also translocated to the aboveground organs in the presence of EDTA. The ex situ experimentation demonstrated that assisted phytoremediation is a very slow process not useful in the case of persistent pollution.

  1. Innovative solidification/stabilization of lead contaminated soil using incineration sewage sludge ash.

    PubMed

    Li, Jiangshan; Poon, Chi Sun

    2017-04-01

    The proper treatment of lead (Pb) contaminated soils and incinerated sewage sludge ash (ISSA) has become an environmental concern. In this study, ordinary Portland cement (OPC) and blended OPC containing incinerated sewage sludge ash (ISSA) were used to solidify/stabilize (S/S) soils contaminated with different concentrations of Pb. After curing for 7 and 28 d, the S/S soils were subjected to a series of strength, leaching and microscopic tests. The results showed that replacement of OPC by ISSA significantly reduced the unconfined compressive strength (UCS) of S/S soils and leached Pb. In addition, the leaching of Pb from the monolithic samples was diffusion controlled, and increasing the ISSA addition in the samples led to a lower diffusion coefficient and thus an increase in the feasibility for "controlled utilization" of S/S soils. Furthermore, the proposed S/S method significantly decreased the amount of Pb associated with carbonates and increased the amount of organic and residual Pb in S/S soils, reflecting that the risk of Pb contaminated soils can be effectively mitigated by the incorporating of ISSA. Overall, the leachability of Pb was controlled by the combined effect of adsorption, encapsulation or precipitation in the S/S soils. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Assessment of soil contamination--a functional perspective.

    PubMed

    van Straalen, Nico M

    2002-01-01

    In many industrialized countries the use of land is impeded by soil pollution from a variety of sources. Decisions on clean-up, management or set-aside of contaminated land are based on various considerations, including human health risks, but ecological arguments do not have a strong position in such assessments. This paper analyses why this should be so, and what ecotoxicology and theoretical ecology can improve on the situation. It seems that soil assessment suffers from a fundamental weakness, which relates to the absence of a commonly accepted framework that may act as a reference. Soil contamination can be assessed both from a functional perspective and a structural perspective. The relationship between structure and function in ecosystems is a fundamental question of ecology which receives a lot of attention in recent literature, however, a general concept that may guide ecotoxicological assessments has not yet arisen. On the experimental side, a good deal of progress has been made in the development and standardized use of terrestrial model ecosystems (TME). In such systems, usually consisting of intact soil columns incubated in the laboratory under conditions allowing plant growth and drainage of water, a compromise is sought between field relevance and experimental manageability. A great variety of measurements can be made on such systems, including microbiological processes and activities, but also activities of the decomposer soil fauna. I propose that these TMEs can be useful instruments in ecological soil quality assessments. In addition a "bioinformatics approach" to the analysis of data obtained in TME experiments is proposed. Soil function should be considered as a multidimensional concept and the various measurements can be considered as indicators, whose combined values define the "normal operating range" of the system. Deviations from the normal operating range indicate that the system is in a condition of stress. It is hoped that more work

  3. Assessment of soil-gas and soil contamination at the South Prong Creek Disposal Area, Fort Gordon, Georgia, 2009-2010

    USGS Publications Warehouse

    Caldwell, Andral W.; Falls, W. Fred; Guimaraes, Wladmir B.; Ratliff, W. Hagan; Wellborn, John B.; Landmeyer, James E.

    2011-01-01

    Soil gas and soil were assessed for contaminants at the South Prong Creek Disposal Area at Fort Gordon, Georgia, from October 2009 to September 2010. The assessment included identifying and delineating organic contaminants present in soil-gas and inorganic contaminants present in soil samples collected from the area estimated to be the South Prong Creek Disposal Area, including two seeps and the hyporheic zone. This assessment was conducted to provide environmental contamination data to Fort Gordon personnel pursuant to requirements for the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. All soil-gas samplers in the two seeps and the hyporheic zone contained total petroleum hydrocarbons above the method detection level. The highest total petroleum hydrocarbon concentration detected from the two seeps was 54.23 micrograms per liter, and the highest concentration in the hyporheic zone was 344.41 micrograms per liter. The soil-gas samplers within the boundary of the South Prong Creek Disposal Area and along the unnamed road contained total petroleum hydrocarbon mass above the method detection level. The highest total petroleum hydrocarbon mass detected was 147.09 micrograms in a soil-gas sampler near the middle of the unnamed road that traverses the South Prong Creek Disposal Area. The highest undecane mass detected was 4.48 micrograms near the location of the highest total petroleum hydrocarbon mass. Some soil-gas samplers detected undecane mass greater than the method detection level of 0.04 micrograms, with the highest detection of toluene mass of 109.72 micrograms in the same location as the highest total petroleum hydrocarbon mass. Soil-gas samplers installed in areas of high contaminant mass had no detections of explosives and chemical agents above their respective method detection levels. Inorganic concentrations in five soil samples did not exceed regional screening levels established by the U.S. Environmental Protection Agency

  4. Analysis of Pollution Hazard Intensity: A Spatial Epidemiology Case Study of Soil Pb Contamination

    PubMed Central

    Ha, Hoehun; Rogerson, Peter A.; Olson, James R.; Han, Daikwon; Bian, Ling; Shao, Wanyun

    2016-01-01

    Heavy industrialization has resulted in the contamination of soil by metals from anthropogenic sources in Anniston, Alabama. This situation calls for increased public awareness of the soil contamination issue and better knowledge of the main factors contributing to the potential sources contaminating residential soil. The purpose of this spatial epidemiology research is to describe the effects of physical factors on the concentration of lead (Pb) in soil in Anniston AL, and to determine the socioeconomic and demographic characteristics of those residing in areas with higher soil contamination. Spatial regression models are used to account for spatial dependencies using these explanatory variables. After accounting for covariates and multicollinearity, results of the analysis indicate that lead concentration in soils varies markedly in the vicinity of a specific foundry (Foundry A), and that proximity to railroads explained a significant amount of spatial variation in soil lead concentration. Moreover, elevated soil lead levels were identified as a concern in industrial sites, neighborhoods with a high density of old housing, a high percentage of African American population, and a low percent of occupied housing units. The use of spatial modelling allows for better identification of significant factors that are correlated with soil lead concentrations. PMID:27649221

  5. Phytoremediation of contaminated soils and groundwater: lessons from the field

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Vangronsveld, J.; van der Lelie, D.; Herzig, R.

    The use of plants and associated microorganisms to remove, contain, inactivate, or degrade harmful environmental contaminants (generally termed phytoremediation) and to revitalize contaminated sites is gaining more and more attention. In this review, prerequisites for a successful remediation will be discussed. The performance of phytoremediation as an environmental remediation technology indeed depends on several factors including the extent of soil contamination, the availability and accessibility of contaminants for rhizosphere microorganisms and uptake into roots (bioavailability), and the ability of the plant and its associated microorganisms to intercept, absorb, accumulate, and/or degrade the contaminants. The main aim is to provide anmore » overview of existing field experience in Europe concerning the use of plants and their associated microorganisms whether or not combined with amendments for the revitalization or remediation of contaminated soils and undeep groundwater. Contaminations with trace elements (except radionuclides) and organics will be considered. Because remediation with transgenic organisms is largely untested in the field, this topic is not covered in this review. Brief attention will be paid to the economical aspects, use, and processing of the biomass. It is clear that in spite of a growing public and commercial interest and the success of several pilot studies and field scale applications more fundamental research still is needed to better exploit the metabolic diversity of the plants themselves, but also to better understand the complex interactions between contaminants, soil, plant roots, and microorganisms (bacteria and mycorrhiza) in the rhizosphere. Further, more data are still needed to quantify the underlying economics, as a support for public acceptance and last but not least to convince policy makers and stakeholders (who are not very familiar with such techniques).« less

  6. In-Situ Electrokinetic Remediation for Metal Contaminated Soils

    DTIC Science & Technology

    2001-03-01

    Press. Riddle, M. J. 1988. Patterns in the distribution of macrofauna! communities in coral reef sediments on the central Great Barrier Reef . Mar...acidified. This acidification results in solubilization of contaminants due to desorption and dissolution of species from soil. Once contaminants are...the north and east, the Pacific Ocean on the south and west, and a Ventura County Game Reserve on the west and northwest (Figure 6). The Navy has

  7. Sorption ability of the soil and its impact on environmental contamination

    PubMed Central

    Gargošová, Helena Zlámalová; Vávrová, Milada

    2014-01-01

    From the physical point of view, soil is a heterogenic polydisperse system. It often becomes a place of a secondary contamination during extinguishing uncontrolled areal fires in nature. Foam extinguishing agents (FEAs), used at these events, basically contain surface active substances and perfluorinated compounds. These tend to be captured in the soil matrix due to their specific properties. Contaminants could be partly flushed out with rainwater, which causes several times dilution of contamination and lower ecotoxic activity. However in the dry season, foam solution infiltrates into the bed soil without any dilution. This study deals with the direct influence of soil the sorption complex on ecotoxicity of five selected FEAs, i.e. Expyrol F 15, Finiflam F 15, Moussol APS F 15, Pyrocool B and Sthamex F 15. The substances tested were prepared in concentration of work solution and then applied on standard soil matrix LUFA 2.3. For experimental purposes, a column infiltration apparatus was designed and compiled. Filtrates were collected and then tested using the plant organisms Sinapis alba and Allium cepa L. The study compared ecotoxicologic effects of filtrates with an original work solution. Moussol APS F 15 seems to be the least ecotoxic of the FEAs tested. A direct influence of soil sorption complex onto ecotoxicity reduction was also established. This finding demonstrates the sorption ability of soil particles and ion exchange activity of the soil matrix. It is a positive finding for biota of aquatic environment, yet at the expense of those in soil. PMID:26109897

  8. Phytoremediation of petroleum hydrocarbon-contaminated saline-alkali soil by wild ornamental Iridaceae species.

    PubMed

    Cheng, Lijuan; Wang, Yanan; Cai, Zhang; Liu, Jie; Yu, Binbin; Zhou, Qixing

    2017-03-04

    As a green remediation technology, phytoremediation is becoming one of the most promising methods for treating petroleum hydrocarbons (PHCs)-contaminated soil. Pot culture experiments were conducted in this study to investigate phytoremediation potential of two representative Iridaceae species (Iris dichotoma Pall. and Iris lactea Pall.) in remediation of petroleum hydrocarbon-contaminated saline-alkali soil from the Dagang Oilfield in Tianjin, China. The results showed that I. lactea was more endurable to extremely high concentration of PHCs (about 40,000 mg/kg), with a relatively high degradation rate of 20.68%.The degradation rate of total petroleum hydrocarbons (TPHs) in soils contaminated with 10,000 and 20,000 mg/kg of PHCs was 30.79% and 19.36% by I. dichotoma, and 25.02% and 19.35% by I. lactea, respectively, which improved by 10-60% than the unplanted controls. The presence of I. dichotoma and I. lactea promoted degradation of PHCs fractions, among which saturates were more biodegradable than aromatics. Adaptive specialization was observed within the bacterial community. In conclusion, phytoremediation by I. dichotoma should be limited to soils contaminated with ≤20,000 mg/kg of PHCs, while I. lactea could be effectively applied to phytoremediation of contaminated soils by PHCs with at least 40,000 mg/kg.

  9. Assessment of cyanide contamination in soils with a handheld mid-infrared spectrometer.

    PubMed

    Soriano-Disla, José M; Janik, Leslie J; McLaughlin, Michael J

    2018-02-01

    We examined the feasibility of using handheld mid-infrared (MIR) Fourier-Transform infrared (FT-IR) instrumentation for detecting and analysing cyanide (CN) contamination in field contaminated soils. Cyanide spiking experiments were first carried out, in the laboratory, to test the sensitivity of infrared Fourier transform (DRIFT) spectrometry to ferro- and ferricyanide compounds across a range of reference soils and minerals. Both benchtop and handheld diffuse reflectance infrared spectrometers were tested. Excellent results were obtained for the reference soils and minerals, with the MIR outperforming the near-infrared (NIR) range. Spectral peaks characteristic of the -C≡N group were observed near 2062 and 2118cm -1 in the MIR region for the ferro- and ferricyanide compounds spiked into soils/minerals, respectively. In the NIR region such peaks were observed near 4134 and 4220cm -1 . Cyanide-contaminated samples were then collected in the field and analyzed with the two spectrometers to further test the applicability of the DRIFT technique for soils containing aged CN residues. The prediction of total CN in dry and ground contaminated soils using the handheld MIR instrument resulted in a coefficient of determination (R 2 ) of 0.88-0.98 and root mean square error of the cross-validation (RMSE) of 21-49mgkg -1 for a CN range of 0-611mgkg -1 . A major peak was observed in the MIR at about 2092cm -1 which was attributed to "Prussian Blue" (Fe 4 [Fe(CN) 6 ] 3 ·xH 2 O). These results demonstrate the potential of handheld DRIFT instrumentation as a promising alternative to the standard laboratory method to predict CN concentrations in contaminated field soils. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  10. Test plan for the soils facility demonstration: A petroleum contaminated soil bioremediation facility

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lombard, K.H.

    1994-08-01

    The objectives of this test plan are to show the value added by using bioremediation as an effective and environmentally sound method to remediate petroleum contaminated soils (PCS) by: demonstrating bioremediation as a permanent method for remediating soils contaminated with petroleum products; establishing the best operating conditions for maximizing bioremediation and minimizing volatilization for SRS PCS during different seasons; determining the minimum set of analyses and sampling frequency to allow efficient and cost-effective operation; determining best use of existing site equipment and personnel to optimize facility operations and conserve SRS resources; and as an ancillary objective, demonstrating and optimizing newmore » and innovative analytical techniques that will lower cost, decrease time, and decrease secondary waste streams for required PCS assays.« less

  11. ENGINEERING ISSUE: IN SITU BIOREMEDIATION OF CONTAMINATED UNSATURATED SUBSURFACE SOILS

    EPA Science Inventory

    An emerging technology for the remediation of unsaturated subsurface soils involves the use of microorganisms to degrade contaminants which are present in such soils. Understanding the processes which drive in situ bioremediation, as well as the effectiveness and efficiency of th...

  12. Laboratory and pilot-scale bioremediation of pentaerythritol tetranitrate (PETN) contaminated soil.

    PubMed

    Zhuang, Li; Gui, Lai; Gillham, Robert W; Landis, Richard C

    2014-01-15

    PETN (pentaerythritol tetranitrate), a munitions constituent, is commonly encountered in munitions-contaminated soils, and pose a serious threat to aquatic organisms. This study investigated anaerobic remediation of PETN-contaminated soil at a site near Denver Colorado. Both granular iron and organic carbon amendments were used in both laboratory and pilot-scale tests. The laboratory results showed that, with various organic carbon amendments, PETN at initial concentrations of between 4500 and 5000mg/kg was effectively removed within 84 days. In the field trial, after a test period of 446 days, PETN mass removal of up to 53,071mg/kg of PETN (80%) was achieved with an organic carbon amendment (DARAMEND) of 4% by weight. In previous laboratory studies, granular iron has shown to be highly effective in degrading PETN. However, for both the laboratory and pilot-scale tests, granular iron was proven to be ineffective. This was a consequence of passivation of the iron surfaces caused by the very high concentrations of nitrate in the contaminated soil. This study indicated that low concentration of organic carbon was a key factor limiting bioremediation of PETN in the contaminated soil. Furthermore, the addition of organic carbon amendments such as the DARAMEND materials or brewers grain, proved to be highly effective in stimulating the biodegradation of PETN and could provide the basis for full-scale remediation of PETN-contaminated sites. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Modification of soil microbial activity and several hydrolases in a forest soil artificially contaminated with copper

    NASA Astrophysics Data System (ADS)

    Bellas, Rosa; Leirós, Mā Carmen; Gil-Sotres, Fernando; Trasar-Cepeda, Carmen

    2010-05-01

    Soils have long been exposed to the adverse effects of human activities, which negatively affect soil biological activity. As a result of their functions and ubiquitous presence microorganisms can serve as environmental indicators of soil pollution. Some features of soil microorganisms, such as the microbial biomass size, respiration rate, and enzyme activity are often used as bioindicators of the ecotoxicity of heavy metals. Although copper is essential for microorganisms, excessive concentrations have a negative influence on processes mediated by microorganisms. In this study we measured the response of some microbial indicators to Cu pollution in a forest soil, with the aim of evaluating their potential for predicting Cu contamination. Samples of an Ah horizon from a forest soil under oakwood vegetation (Quercus robur L.) were contaminated in the laboratory with copper added at different doses (0, 120, 360, 1080 and 3240 mg kg-1) as CuCl2×2H2O. The soil samples were kept for 7 days at 25 °C and at a moisture content corresponding to the water holding capacity, and thereafter were analysed for carbon and nitrogen mineralization capacity, microbial biomass C, seed germination and root elongation tests, and for urease, phosphomonoesterase, catalase and ß-glucosidase activities. In addition, carbon mineralization kinetics were studied, by plotting the log of residual C against incubation time, and the metabolic coefficient, qCO2, was estimated. Both organic carbon and nitrogen mineralization were lower in polluted samples, with the greatest decrease observed in the sample contaminated with 1080 mg kg-1. In all samples carbon mineralization followed first order kinetics; the C mineralization constant was lower in contaminated than in uncontaminated samples and, in general, decreased with increasing doses of copper. Moreover, it appears that copper contamination not only reduced the N mineralization capacity, but also modified the N mineralization process, since in

  14. Effect of volatile hydrocarbon fractions on mobility and earthworm uptake of polycyclic aromatic hydrocarbons from soils and soil/lampblack mixtures.

    PubMed

    Bogan, Bill W; Beardsley, Kate E; Sullivan, Wendy R; Hayes, Thomas D; Soni, Bhupendra K

    2005-01-01

    Studies were conducted to examine the mobility and bioavailability to earthworms (Eisenia fetida) of priority pollutant polycyclic aromatic hydrocarbons (PAH) in a suite of 11 soils and soil/lampblack mixtures obtained from former manufactured-gas plant sites. Contaminant mobility was assessed using XAD4 resins encapsulated in dialysis tubing, which were exposed to slurried soils for 15 d. These experiments showed that mobility of PAH in the different soils strongly correlated to the levels of volatile hydrocarbons (namely, gasoline- and diesel-range organics [GRO and DRO]) that existed in the soils as co-contaminants. Actual PAH bioavailability (as measured by earthworm PAH concentrations) also appeared to depend on GRO + DRO levels, although this was most evident at high levels of these contaminants. These findings are discussed in view of the effects of dieselrange organics on oil viscosity, assuming that the hydrocarbon contaminants in these soils exist in the form of distinct adsorbed oil phases. This study, therefore, extends correlations between carrier-oil viscosity and dissolved solute bioavailability, previously observed in a number of other in vitro and whole-organism tests (and in bacterial mutagenicity studies in soil), to multicellular organisms inhabiting contaminated-soil systems.

  15. Evaluating cadmium bioavailability in contaminated rice paddy soils and assessing potential for contaminant immobilisation with biochar.

    PubMed

    Kosolsaksakul, Peerapat; Oliver, Ian W; Graham, Margaret C

    2018-06-01

    Cadmium (Cd) contaminated soils from the Mae Sot district in northwest Thailand, a region in which rice Cd concentrations often exceed health limits (0.4 mg/kg) set by the World Health Organisation, were examined for isotopically exchangeable Cd (Cd E values using a 111 Cd spike) to determine how this rates as a predictor of rice grain Cd in comparison with soil total Cd and solution extractable Cd (using the commonly applied BCR scheme and, in an attempt to distinguish carbonate bound forms, the Tessier soil sequential extraction scheme reagents). Step 1 of the BCR scheme (0.11 M CH 3 COOH) and step 1 of the Tessier scheme (1M MgCl 2 ) showed the highest R 2 values in regressions with rice Cd (91% and 90%, respectively), but all predictors were strongly linked to rice Cd (p < 0.001) and could be used for prediction purposes. One soil, of the six tested, was an exception to this, where all predictors over-estimated grain Cd by a factor of 2.5-5.7, suggesting that rice grain Cd had been restricted here by the differing flooding regime and subsequent changes to redox conditions. E values and Tessier step 1 extractions were closely related, indicating that these measurements access similar pools of soil Cd. Separately, the isotopic exchangeability (representing bioavailability) of Cd was also assessed in two soils amended with rice husk and miscanthus biochars (0, 1, 5, 10, 15 and 20% w/w) in order to assess the utility of the biochars as a soil amendment for immobilising Cd in situ. One soil showed significant reductions in Cd E value at 5% rice husk biochar addition and at 15% miscanthus biochar addition however, based on the E value-rice grain Cd regression relationship previously established, the E values in the amended soils still predicted for a rice Cd concentration above the health limit. In the second soil, neither of the biochars successfully reduced the Cd E value. This indicates that further work is needed to customise biochar properties to suit

  16. FORMATION OF CHLOROPYROMORPHITE IN A LEAD-CONTAMINATED SOIL AMENDED WITH HYDROXYAPATITE

    EPA Science Inventory

    To evaluate conversion of soil Pb to pyromorphite, a Pb contaminated soil collected adjacent to a historical smelter was reacted with hydroxyapatite in a traditional incubation experiment and in a dialysis system in which the soil and hydroxyapatite solids were separated by a dia...

  17. Organic contamination and remediation in the agricultural soils of China: A critical review.

    PubMed

    Sun, Jianteng; Pan, Lili; Tsang, Daniel C W; Zhan, Yu; Zhu, Lizhong; Li, Xiangdong

    2018-02-15

    Soil pollution is a global problem in both developed and developing countries. Countries with rapidly developing economies such as China are faced with significant soil pollution problems due to accelerated industrialization and urbanization over the last decades. This paper provides an overview of published scientific data on soil pollution across China with particular focus on organic contamination in agricultural soils. Based on the related peer-reviewed papers published since 2000 (n=203), we evaluated the priority organic contaminants across China, revealed their spatial and temporal distributions at the national scale, identified their possible sources and fates in soil, assessed their potential environmental risks, and presented the challenges in current remediation technologies regarding the combined organic pollution of agricultural soils. The primary pollutants in Northeast China were polycyclic aromatic hydrocarbons (PAHs) due to intensive fossil fuel combustion. The concentrations of organochlorine pesticides (OCPs) and phthalic acid esters (PAEs) were higher in North and Central China owing to concentrated agricultural activities. The levels of polychlorinated biphenyls (PCBs) were higher in East and South China primarily because of past industrial operations and improper electronic waste processing. The co-existence of organic contaminants was severe in the Yangtze River Delta, Pearl River Delta, and Beijing-Tianjin-Hebei Region, which are the most populated and industrialized regions in China. Integrated biological-chemical remediation technologies, such as surfactant-enhanced bioremediation, have potential uses in the remediation of soil contaminated by multiple contaminants. This critical review highlighted several future research directions including combined pollution, interfacial interactions, food safety, bioavailability, ecological effects, and integrated remediation methods for combined organic pollution in soil. Copyright © 2017 Elsevier B

  18. A combined approach of physicochemical and biological methods for the characterization of petroleum hydrocarbon-contaminated soil.

    PubMed

    Masakorala, Kanaji; Yao, Jun; Chandankere, Radhika; Liu, Haijun; Liu, Wenjuan; Cai, Minmin; Choi, Martin M F

    2014-01-01

    Main physicochemical and microbiological parameters of collected petroleum-contaminated soils with different degrees of contamination from DaGang oil field (southeast of Tianjin, northeast China) were comparatively analyzed in order to assess the influence of petroleum contaminants on the physicochemical and microbiological properties of soil. An integration of microcalorimetric technique with urease enzyme analysis was used with the aim to assess a general status of soil metabolism and the potential availability of nitrogen nutrient in soils stressed by petroleum-derived contaminants. The total petroleum hydrocarbon (TPH) content of contaminated soils varied from 752.3 to 29,114 mg kg(−1). Although the studied physicochemical and biological parameters showed variations dependent on TPH content, the correlation matrix showed also highly significant correlation coefficients among parameters, suggesting their utility in describing a complex matrix such as soil even in the presence of a high level of contaminants. The microcalorimetric measures gave evidence of microbial adaptation under highest TPH concentration; this would help in assessing the potential of a polluted soil to promote self-degradation of oil-derived hydrocarbon under natural or assisted remediation. The results highlighted the importance of the application of combined approach in the study of those parameters driving the soil amelioration and bioremediation.

  19. An overview of electrokinetic soil flushing and its effect on bioremediation of hydrocarbon contaminated soil.

    PubMed

    Ramadan, Bimastyaji Surya; Sari, Gina Lova; Rosmalina, Raden Tina; Effendi, Agus Jatnika; Hadrah

    2018-07-15

    Combination of electrokinetic soil flushing and bioremediation (EKSF-Bio) technology has attracted many researchers attention in the last few decades. Electrokinetic is used to increase biodegradation rate of microorganisms in soil pores. Therefore, it is necessary to use solubilizing agents such as surfactants that can improve biodegradation process. This paper describes the basic understanding and recent development associated with electrokinetic soil flushing, bioremediation, and its combination as innovative hybrid solution for treating hydrocarbon contaminated soil. Surfactant has been widely used in many studies and practical applications in remediation of hydrocarbon contaminant, but specific review about those combination technology cannot be found. Surfactants and other flushing/solubilizing agents have significant effects to increase hydrocarbon remediation efficiency. Thus, this paper is expected to provide clear information about fundamental interaction between electrokinetic, flushing agents and bioremediation, principal factors, and an inspiration for ongoing and future research benefit. Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. Soil and plant contamination with Mycobacterium avium subsp. paratuberculosis after exposure to naturally contaminated mouflon feces.

    PubMed

    Pribylova, Radka; Slana, Iva; Kaevska, Marija; Lamka, Jiri; Babak, Vladimir; Jandak, Jiri; Pavlik, Ivo

    2011-05-01

    The aim of this study was to demonstrate the persistence of Mycobacterium avium subsp. paratuberculosis (MAP) in soil and colonization of different plant parts after deliberate exposure to mouflon feces naturally contaminated with different amounts of MAP. Samples of aerial parts of plants, their roots, and the soil below the roots were collected after 15 weeks and examined using IS900 real-time quantitative PCR (qPCR) and cultivation. Although the presence of viable MAP cells was not demonstrated, almost all samples were found to be positive using qPCR. MAP IS900 was not only found in the upper green parts, but also in the roots and soil samples (from 1.00 × 10(0) to 6.43 × 10(3)). The level of soil and plant contamination was influenced mainly by moisture, clay content, and the depth from which the samples were collected, rather than by the initial concentration of MAP in the feces at the beginning of the experiment.

  1. Initial-phase optimization for bioremediation of munition compound-contaminated soils.

    PubMed Central

    Funk, S B; Roberts, D J; Crawford, D L; Crawford, R L

    1993-01-01

    We examined the bioremediation of soils contaminated with the munition compounds 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine, and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetraazocine by a procedure that produced anaerobic conditions in the soils and promoted the biodegradation of nitroaromatic contaminants. This procedure consisted of flooding the soils with 50 mM phosphate buffer, adding starch as a supplemental carbon substrate, and incubating under static conditions. Aerobic heterotrophs, present naturally in the soil or added as an inoculum, quickly removed the oxygen from the static cultures, creating anaerobic conditions. Removal of parent TNT molecules from the soil cultures by the strictly anaerobic microflora occurred within 4 days. The reduced intermediates formed from TNT and hexahydro-1,3,5-trinitro-1,3,5-triazine were removed from the cultures within 24 days, completing the first stage of remediation. The procedure was effective over a range of incubation temperatures, 20 to 37 degrees C, and was improved when 25 mM ammonium was added to cultures buffered with 50 mM potassium phosphate. Ammonium phosphate buffer (50 mM), however, completely inhibited TNT reduction. The optimal pH for the first stage of remediation was between 6.5 and 7.0. When soils were incubated under aerobic conditions or under anaerobic conditions at alkaline pHs, the TNT biodegradation intermediates polymerized. Polymerization was not observed at neutral to slightly acidic pHs under anaerobic conditions. Completion of the first stage of remediation of munition compound-contaminated soils resulted in aqueous supernatants that contained no munition residues or aminoaromatic compounds. PMID:8357251

  2. REMEDIATING PESTICIDE CONTAMINATED SOILS USING SOLVENT EXTRACTION

    EPA Science Inventory

    Bench-scale solvent extraction studies were performed on soil samples obtained from a Superfund site contaminated with high levels of p,p'-DDT, p,p'-DDD,, p,p'-DDE and toxaphene. The effectiveness of the solvent extraction process was assessed using methanol and 2-propanol as sol...

  3. Remediation of heavy metal contaminated soils by using Solanum nigrum: A review.

    PubMed

    Rehman, Muhammad Zia Ur; Rizwan, Muhammad; Ali, Shafaqat; Ok, Yong Sik; Ishaque, Wajid; Saifullah; Nawaz, Muhammad Farrakh; Akmal, Fatima; Waqar, Maqsooda

    2017-09-01

    Heavy metals are among the major environmental pollutants and the accumulation of these metals in soils is of great concern in agricultural production due to the toxic effects on crop growth and food quality. Phytoremediation is a promising technique which is being considered as an alternative and low-cost technology for the remediation of metal-contaminated soils. Solanum nigrum is widely studied for the remediation of heavy metal-contaminated soils owing to its ability for metal uptake and tolerance. S. nigrum can tolerate excess amount of certain metals through different mechanism including enhancing the activities of antioxidant enzymes and metal deposition in non-active parts of the plant. An overview of heavy metal uptake and tolerance in S. nigrum is given. Both endophytic and soil microorganisms can play a role in enhancing metal tolerance in S. nigrum. Additionally, optimization of soil management practices and exogenous application of amendments can also be used to enhance metal uptake and tolerance in this plant. The main objective of the present review is to highlight and discuss the recent progresses in using S. nigrum for remediation of metal contaminated soils. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Depth-resolved microbial community analyses in two contrasting soil cores contaminated by antimony and arsenic.

    PubMed

    Xiao, Enzong; Krumins, Valdis; Xiao, Tangfu; Dong, Yiran; Tang, Song; Ning, Zengping; Huang, Zhengyu; Sun, Weimin

    2017-02-01

    Investigation of microbial communities of soils contaminated by antimony (Sb) and arsenic (As) is necessary to obtain knowledge for their bioremediation. However, little is known about the depth profiles of microbial community composition and structure in Sb and As contaminated soils. Our previous studies have suggested that historical factors (i.e., soil and sediment) play important roles in governing microbial community structure and composition. Here, we selected two different types of soil (flooded paddy soil versus dry corn field soil) with co-contamination of Sb and As to study interactions between these metalloids, geochemical parameters and the soil microbiota as well as microbial metabolism in response to Sb and As contamination. Comprehensive geochemical analyses and 16S rRNA amplicon sequencing were used to shed light on the interactions of the microbial communities with their environments. A wide diversity of taxonomical groups was present in both soil cores, and many were significantly correlated with geochemical parameters. Canonical correspondence analysis (CCA) and co-occurrence networks further elucidated the impact of geochemical parameters (including Sb and As contamination fractions and sulfate, TOC, Eh, and pH) on vertical distribution of soil microbial communities. Metagenomes predicted from the 16S data using PICRUSt included arsenic metabolism genes such as arsenate reductase (ArsC), arsenite oxidase small subunit (AoxA and AoxB), and arsenite transporter (ArsA and ACR3). In addition, predicted abundances of arsenate reductase (ArsC) and arsenite oxidase (AoxA and AoxB) genes were significantly correlated with Sb contamination fractions, These results suggest potential As biogeochemical cycling in both soil cores and potentially dynamic Sb biogeochemical cycling as well. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Heavy metal (Cu, Zn, Cd and Pb) partitioning and bioaccessibility in uncontaminated and long-term contaminated soils.

    PubMed

    Lamb, Dane T; Ming, Hui; Megharaj, Mallavarapu; Naidu, Ravi

    2009-11-15

    We investigated the pore-water content and speciation of copper (Cu), zinc (Zn), cadmium (Cd) and lead (Pb) in a range of uncontaminated and long-term contaminated soils in order to establish their potential bioaccessibility to soil biota, plants and humans. Among the samples, soil pH (0.01 M CaCl(2)) ranged from 4.9 to 8.2. The total metal content of the uncontaminated soils ranged from 3.8 to 93.8 mg Cu kg(-1), 10.3 to 95 mg kg(-1) Zn, 0.1 to 1.8 mg Cd kg(-1) and 5.2 to 183 mg kg(-1) Pb, while metal content in the contaminated soils ranged from 104 to 6841 mg Cu kg(-1), 312 to 39,000 mg kg(-1) Zn, 6 to 302 mg Cd kg(-1) and 609 to 12,000 mg kg(-1) Pb. Our analysis of pore-water found the Cu concentrations to be much higher in contaminated soils than in uncontaminated soils, with the distribution coefficients (K(d)) correlating significantly with the log of dissolved organic carbon concentrations. Despite the high total metal content of the contaminated soil, Zn, Cd and Pb were not generally found at elevated levels in the pore-water with the exception of a single contaminated soil. A long period of ageing and soil weathering may have led to a substantial reduction in heavy metal concentrations in the pore-water of contaminated soils. On the other hand, Pb bioaccessibility was found to be comparatively high in Pb contaminated soils, where it tended to exceed the total Pb values by more than 80%. We conclude that, despite the extensive ageing of some contaminated soils, the bioaccessibility of Pb remains relatively high.

  6. Bio-augmentation and nutrient amendment decrease concentration of mercury in contaminated soil.

    PubMed

    Mahbub, Khandaker Rayhan; Krishnan, Kannan; Andrews, Stuart; Venter, Henrietta; Naidu, Ravi; Megharaj, Mallavarapu

    2017-01-15

    Four mercury (Hg) contaminated soils with different pH (7.6, 8.5, 4.2 and 7.02) and total organic carbon contents (2.1, 2.2, 4 and 0.9%) were subjected to bioremediation utilizing a Hg volatilizing bacterial strain Sphingobium SA2 and nutrient amendment. In a field with ~280mg/kgHg, 60% of Hg was removed by bio-augmentation in 7days, and the removal was improved when nutrients were added. Whereas in artificially spiked soils, with ~100mg/kgHg, removal due to bio-augmentation was 33 to 48% in 14days. In the field contaminated soil, nutrient amendment alone without bio-augmentation removed 50% of Hg in 28days. Nutrient amendment also had an impact on Hg remediation in the spiked soils, but the best results were obtained when the strain and nutrients both were applied. The development of longer root lengths from lettuce and cucumber seeds grown in the remediated soils confirmed that the soil quality improved after bioremediation. This study clearly demonstrates the potential of Hg-reducing bacteria in remediation of Hg-contaminated soils. However, it is desirable to trap the volatilized Hg for enhanced bioremediation. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Electrochemical Processes for In-Situ Treatment of Contaminated Soils - Final Report - 09/15/1996 - 01/31/2001

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Huang, Chin-Pao

    2001-05-31

    This project will study electrochemical processes for the in situ treatment of soils contaminated by mixed wastes, i.e., organic and inorganic. Soil samples collected form selected DOE waste sites will be characterized for specific organic and metal contaminants and hydraulic permeability. The soil samples are then subject to desorption experiments under various physical-chemical conditions such as pH and the presence of surfactants. Batch electro-osmosis experiments will be conducted to study the transport of contaminants in the soil-water systems. Organic contaminants that are released from the soil substrate will be treated by an advanced oxidation process, i.e., electron-Fantan. Finally, laboratory reactormore » integrating the elector-osmosis and elector-Fantan processes will be used to study the treatment of contaminated soil in situ.« less

  8. Plant uptake of explosives from contaminated soil at the Joliet Army Ammunition Plant

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zellmer, S.D.; Schneider, J.F.; Tomczyk, N.A.

    1995-04-01

    Explosives and their degradation products may enter the animal and human food chains through plants grown on soils contaminated with explosives. Soil and plant samples were collected from the Group 61 area at the Joliet Army Ammunition Plant and analyzed to determine the extent to which 2,4,6-trinitrotoluene (TNT) and its degradation products are taken up by existing vegetation and crops growing on contaminated soils. Neither TNT nor its degradation products was detected in any of the aboveground plant organs of existing vegetation. Oat (Avena sativa L.) and perennial ryegrass (Lolium perenne L.) were planted on TNT-contaminated soils amended with threemore » levels of chopped grass hay. Extractable TNT concentrations in hay-amended soils were monitored for almost 1 year. Crop establishment and growth improved with increased levels of hay amendment, but TNT uptake was not affected or detected in any aboveground crop organs. Evidence was found to indicate that soil manipulation and hay addition may reduce extractable TNT concentration in soils, but the wide variations in TNT concentrations in these soils prevented development of conclusive evidence regarding reduction of extractable TNT concentrations. Results from this study suggest that vegetation grown on TNT-contaminated soils is not a major health concern because TNT and its degradation products were not detected in aboveground plant organs. However, low concentrations of TNT, 4-amino-2,6-dinitrotoluene, and 2-amino-4,6-dinitrotoluene were detected in or on some existing vegetation and crop roots. 21 refs., 10 figs., 26 tabs.« less

  9. Integrated electrokinetics-adsorption remediation of saline-sodic soils: effects of voltage gradient and contaminant concentration on soil electrical conductivity.

    PubMed

    Essa, Mohammed Hussain; Mu'azu, Nuhu Dalhat; Lukman, Salihu; Bukhari, Alaadin

    2013-01-01

    In this study, an integrated in situ remediation technique which couples electrokinetics with adsorption, using locally produced granular activated carbon from date palm pits in the treatment zones that are installed directly to bracket the contaminated soils at bench-scale, is investigated. Natural saline-sodic clay soil, spiked with contaminant mixture (kerosene, phenol, Cr, Cd, Cu, Zn, Pb, and Hg), was used in this study to investigate the effects of voltage gradient, initial contaminant concentration, and polarity reversal rate on the soil electrical conductivity. Box-Behnken Design (BBD) was used for the experimental design and response surface methodology (RSM) was employed to model, optimize, and interpret the results obtained using Design-Expert version 8 platform. The total number of experiments conducted was 15 with voltage gradient, polarity reversal rate, and initial contaminant concentration as variables. The main target response discussed in this paper is the soil electrical conductivity due to its importance in electrokinetic remediation process. Responses obtained were fitted to quadratic models whose R (2) ranges from 84.66% to 99.19% with insignificant lack of fit in each case. Among the investigated factors, voltage gradient and initial contaminant concentration were found to be the most significant influential factors.

  10. EFFECT OF SOIL PB INACTIVATION TREATMENTS ON BIOAVAILABILITY OF JOPLIN, MO, SMELTER CONTAMINATED SOIL PB TO RATS

    EPA Science Inventory

    The effects of treating contaminated soils with various soil amendments on the bioavailability of lead were assessed in the weanling rat model. The effect of treatment was assessed by comparing the adsorption of Pb of animals fed soil samples treated with (0.5%, 1% P and 2.5% Fe ...

  11. Leaching of PFC from soils contaminated with PFC of different origin

    NASA Astrophysics Data System (ADS)

    Kalbe, Ute; Piechotta, Christian; Rothe, Robert

    2017-04-01

    Leaching tests are fundamental tools for the assessment of groundwater impact by contaminated soils concerning the soil-groundwater pathway. Such procedures are supposed to serve as the basis for a reliable leachate prognosis. They can be applied to determine the short and long term leaching behaviour as well as the source term of contaminated soils. For this purpose two types of leaching procedures have been validated in Germany for the examination of the leaching behaviour of frequently occurring organic substances (DIN 19528 - column test and DIN 19529 - batch test). A liquid-to-solid ratio (L/S) of 2 L/kg and 10 L/kg) is the basis for the risk assessment which is implemented in different German regulations. The equivalence of test results for both tests for the same material under investigation has been investigated for a variety of pollutants in order to assess their reliability in compliance testing. However, for emerging pollutants there is hardly data available on this issue. Leaching tests on soils contaminated with emerging pollutants such as PFC (Perfluorinated Surfactants) are currently coming more into consideration due to the increasing detection of contaminated sites. Therefore, two soils were investigated in this study from different contamination source (paper sludge containing compost and fire distinguishing foam) using both leaching tests and both liquid-to-solid ratios. The leachability of the various perfluorinated compounds in relation to their content in solid matter was considered. Furthermore the eluate pre-treatment prior analysis (in particular liquid/solid separation step needed for batch tests) has been taken into account. The comparability of the results from batch and column is dependent on the solubility of the various compounds, on the L/S and on the turbidity in the eluates.

  12. Removal of fluorine from contaminated soil by electrokinetic treatment driven by solar energy.

    PubMed

    Zhou, Ming; Zhu, Shufa; Liu, Yana; Wang, Xuejian

    2013-08-01

    Instead of direct current power supply, a series of electrokinetic remediation experiments driven by solar energy on fluorine-contaminated soil were conducted in a self-made electrolyzer, in order to reduce energy expenditure of electrokinetic remediation. After the 12-day electrokinetic remediation driven by solar energy, the removal efficiency of fluorine was 22.3%, and electrokinetic treatment had an impact on changes in partitioning of fluorine in soil. It proved that the combination of electrokinetics and solar energy was feasible and effective to some extent for the remediation of fluorine-contaminated soil. Meanwhile, the experimental results also indicated that the electromigration was a more dominant transport mechanism for the removal of fluorine from contaminated soil than electroosmosis, and the weather condition was the important factor in affecting the removal efficiency.

  13. Complex conductivity of oil-contaminated clayey soils

    NASA Astrophysics Data System (ADS)

    Deng, Y.; Revil, A.; Shi, X.

    2017-12-01

    Non-intrusive hydrogeophysical techniques have been wildly applied to detect organic contaminants because of the difference of electrical properties for contaminated soil. Among them, spectral induced polarization (SIP) has emerged as a promising tool for the identification of contamination due to its sensitivity to the chemistry of pore water, solid-fluid interfaces and fluid content. Previous works have investigated the influences of oil on the electrical signatures of porous media, which demonstrated the potentials of SIP in the detection of hydrocarbon contamination. However, few works have done on the SIP response of oil in clayey soils. In this study, we perform a set of SIP measurements on the clayey samples under different water saturations. These clayey soils are characterized by relatively high cation exchange capacity. The objective in this work is to test the empirical relationships between the three exponents, including the cementation exponent (m), the saturation exponent (n) and the quadrature conductivity exponent (p), which is expected to reduce the model parameters needed in geophysical and hydraulic properties predictions. Our results show that the complex conductivity are saturation dependent. The magnitude of both in-phase and quadrature conductivities generally decrease with decreasing water saturation. The shape of quadrature conductivity spectra slightly changes when water saturation decreases in some cases. The saturation exponent slightly increases with cation exchange capacity, specific surface area and clay content, with an average value around 2.05. Compared to saturation exponent, the quadrature conductivity exponent apparently increases with cation exchange capacity and specific surface area while has little to do with the clay content. Further, the results indicate that the quadrature conductivity exponent p does not strictly obey to p=n-1 as proposed by Vinegar and Waxman (1984). Instead, it mostly ranges between p=n-1.5 and p=n-0

  14. Cadmium contamination of agricultural soils and crops resulting from sphalerite weathering.

    PubMed

    Robson, T C; Braungardt, C B; Rieuwerts, J; Worsfold, P

    2014-01-01

    The biogeochemistry and bioavailability of cadmium, released during sphalerite weathering in soils, were investigated under contrasting agricultural scenarios to assess health risks associated with sphalerite dust transport to productive soils from mining. Laboratory experiments (365 d) on temperate and sub-tropical soils amended with sphalerite (<63 μm, 0.92 wt.% Cd) showed continuous, slow dissolution (0.6-1.2% y(-1)). Wheat grown in spiked temperate soil accumulated ≈38% (29 μmol kg(-1)) of the liberated Cd, exceeding food safety limits. In contrast, rice grown in flooded sub-tropical soil accumulated far less Cd (0.60 μmol kg(-1)) due to neutral soil pH and Cd bioavailability was possibly also controlled by secondary sulfide formation. The results demonstrate long-term release of Cd to soil porewaters during sphalerite weathering. Under oxic conditions, Cd may be sufficiently bioavailable to contaminate crops destined for human consumption; however flooded rice production limits the impact of sphalerite contamination. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Reducing the bioavailability of cadmium in contaminated soil by dithiocarbamate chitosan as a new remediation.

    PubMed

    Yin, Zheng; Cao, Jingjing; Li, Zhen; Qiu, Dong

    2015-07-01

    Dithiocarbamate chitosan (DTC-CTS) was used as a new amendment for remediation of cadmium (Cd)-contaminated soils to reduce the Cd bioavailability. Arabidopsis thaliana was chosen as a model plant to evaluate its efficiency. It was found that DTC-CTS could effectively improve the growth of A. thaliana. The amount of Cd up-taken by A. thaliana could be decreased by as much as 50% compared with that grown in untreated Cd-contaminated soil samples. The chlorophyll content and the aerial biomass of Arabidopsis also increased substantially and eventually returned to a level comparable to plants grown in non-contaminated soils, with the addition of DTC-CTS. These findings suggested that DTC-CTS amendment could be effective in immobilizing Cd and mitigating its accumulation in plants grown in Cd-contaminated soils, with potential application as an in situ remediation of Cd-polluted soils.

  16. Analysis of Actual Soil Degradation by Erosion Using Satellite Imagery and Terrain Attributes in the Czech Republic

    NASA Astrophysics Data System (ADS)

    Zizala, Daniel

    2015-04-01

    Soil water and wind erosion (possibly tillage erosion) is the most significant soil degradation factor in the Czech Republic. Moreover, this phenomenon also affects seriously quality of water sources., About 50 % of arable land are endangered by water erosion and about 10 % of arable land are endangered wind erosion in the Czech Republic. These processes have been accelerated by human activity. Specific condition of agriculture land in the Czech Republic including highland relief and particularly size of land parcel and intensification of agriculture does not enable to reduce flow of runoff water. Insufficient protection against accelerated erosion processes is related to lack of landscape and hydrographic elements and large area of agricultural plots. Currently, this issue is solved at plot scale by field investigation or at regional scale using numerical and empirical erosion models. Nevertheless, these models enable only to predict the potential of soil erosion. Large scale assessment of actual degradation level of soils is based on expert knowledge. However, there are still many uncertainties in this issue. Therefore characterization of actual degradation level of soil is required especially for assessment of long-term impact of soil erosion on soil fertility. Soil degradation by erosion can be effectively monitored or quantified by modern tools of remote sensing with variable level of detail accessible. Aims of our study is to analyse the applicability of remote sensing for monitoring of actual soil degradation by erosion. Satellite and aerial image data (multispectral and hyperspectral), terrain attributes and data from field investigation are the main source for this analyses. The first step was the delimitation of bare soils using supervised classification of the set of Landsat scenes from 2000 - 2014. The most suitable period of time for obtaining spectral image data with the lowest vegetation cover of soil was determined. The results were verified by

  17. Relating soil solution Zn concentration to diffusive gradients in thin films measurements in contaminated soils.

    PubMed

    Degryse, Fien; Smolders, Erik; Oliver, Ian; Zhang, Hao

    2003-09-01

    The technique of diffusive gradients in thin films (DGT) has been suggested to sample an available fraction of metals in soil. The objectives of this study were to compare DGT measurements with commonly measured fractions of Zn in soil, viz, the soil solution concentration and the total Zn concentration. The DGT technique was used to measure fluxes and interfacial concentrations of Zn in three series of field-contaminated soils collected in transects toward galvanized electricity pylons and in 15 soils amended with ZnCl2 at six rates. The ratio of DGT-measured concentration to pore water concentration of Zn, R, varied between 0.02 and 1.52 (mean 0.29). This ratio decreased with decreasing distribution coefficient, Kd, of Zn in the soil, which is in agreement with the predictions of the DGT-induced fluxes in soils (DIFS) model. The R values predicted with the DIFS model were generally larger than the observed values in the ZnCl2-amended soils at the higher Zn rates. A modification of the DIFS model indicated that saturation of the resin gel was approached in these soils, despite the short deployment times used (2 h). The saturation of the resin with Zn did not occur in the control soils (no Zn salt added) or the field-contaminated soils. Pore water concentration of Zn in these soils was predicted from the DGT-measured concentration and the total Zn content. Predicted values and observations were generally in good agreement. The pore water concentration was more than 5 times underpredicted for the most acid soil (pH = 3) and for six other soils, for which the underprediction was attributed to the presence of colloidal Zn in the soil solution.

  18. Zinc Speciation in Proximity to Phosphate Application Points in a Lead/Zinc Smelter-Contaminated Soil

    EPA Science Inventory

    The use of P to immobilize Pb in contaminated soils has been well documented. However, the influence of P on Zn speciation in soils has not been extensively examined, and these two metals often occur as co-contaminants. We hypothesized that additions of P to a Pb/Zn-contaminate...

  19. Concept of Aided Phytostabilization of Contaminated Soils in Postindustrial Areas

    PubMed Central

    Koda, Eugeniusz; Bilgin, Ayla; Vaverková, Mgdalena D.

    2017-01-01

    The experiment was carried out in order to evaluate the effects of trace element immobilizing soil amendments, i.e., chalcedonite, dolomite, halloysite, and diatomite on the chemical characteristics of soil contaminated with Cr and the uptake of metals by plants. The study utilized analysis of variance (ANOVA), principal component analysis (PCA) and Factor Analysis (FA). The content of trace elements in plants, pseudo-total and extracted by 0.01 M CaCl2, were determined using the method of spectrophotometry. All of the investigated element contents in the tested parts of Indian mustard (Brassica juncea L.) differed significantly in the case of applying amendments to the soil, as well as Cr contamination. The greatest average above-ground biomass was observed when halloysite and dolomite were amended to the soil. Halloysite caused significant increases of Cr concentrations in the roots. The obtained values of bioconcentration and translocation factors observed for halloysite treatment indicate the effectiveness of using Indian mustard in phytostabilization techniques. The addition of diatomite significantly increased soil pH. Halloysite and chalcedonite were shown to be the most effective and decreased the average Cr, Cu and Zn contents in soil. PMID:29295511

  20. Concept of Aided Phytostabilization of Contaminated Soils in Postindustrial Areas.

    PubMed

    Radziemska, Maja; Koda, Eugeniusz; Bilgin, Ayla; Vaverková, Mgdalena D

    2017-12-23

    The experiment was carried out in order to evaluate the effects of trace element immobilizing soil amendments, i.e., chalcedonite, dolomite, halloysite, and diatomite on the chemical characteristics of soil contaminated with Cr and the uptake of metals by plants. The study utilized analysis of variance (ANOVA), principal component analysis (PCA) and Factor Analysis (FA). The content of trace elements in plants, pseudo-total and extracted by 0.01 M CaCl₂, were determined using the method of spectrophotometry. All of the investigated element contents in the tested parts of Indian mustard ( Brassica juncea L.) differed significantly in the case of applying amendments to the soil, as well as Cr contamination. The greatest average above-ground biomass was observed when halloysite and dolomite were amended to the soil. Halloysite caused significant increases of Cr concentrations in the roots. The obtained values of bioconcentration and translocation factors observed for halloysite treatment indicate the effectiveness of using Indian mustard in phytostabilization techniques. The addition of diatomite significantly increased soil pH. Halloysite and chalcedonite were shown to be the most effective and decreased the average Cr, Cu and Zn contents in soil.

  1. Remediation of contaminated soils by enhanced nanoscale zero valent iron.

    PubMed

    Jiang, Danni; Zeng, Guangming; Huang, Danlian; Chen, Ming; Zhang, Chen; Huang, Chao; Wan, Jia

    2018-05-01

    The use of nanoscale zero valent iron (nZVI) for in situ remediation of soil contamination caused by heavy metals and organic pollutants has drawn great concern, primarily owing to its potential for excellent activity, low cost and low toxicity. This reviews considers recent advances in our understanding of the role of nZVI and enhanced nZVI strategy in the remediation of heavy metals and persistent organic contaminants polluted soil. The performance, the migration and transformation of nZVI affected by the soil physical and chemical conditions are summarized. However, the addition of nZVI inevitably disturbs the soil ecosystem, thus the impacts of nZVI on soil organisms are discussed. In order to further investigate the remediation effect of nZVI, physical, chemical and biological method combination with nZVI was developed to enhance the performance of nZVI. From a high efficient and environmentally friendly perspective, biological method enhanced nZVI technology will be future research needs. Possible improvement of nZVI-based materials and potential areas for further applications in soil remediation are also proposed. Copyright © 2018 Elsevier Inc. All rights reserved.

  2. Sand amendment enhances bioelectrochemical remediation of petroleum hydrocarbon contaminated soil.

    PubMed

    Li, Xiaojing; Wang, Xin; Ren, Zhiyong Jason; Zhang, Yueyong; Li, Nan; Zhou, Qixing

    2015-12-01

    Bioelectrochemical system is an emerging technology for the remediation of soils contaminated by petroleum hydrocarbons. However, performance of such systems can be limited by the inefficient mass transport in soil. Here we report a new method of sand amendment, which significantly increases both oxygen and proton transports, resulting to increased soil porosity (from 44.5% to 51.3%), decreased Ohmic resistance (by 46%), and increased charge output (from 2.5 to 3.5Cg(-1)soil). The degradation rates of petroleum hydrocarbons increased by up to 268% in 135d. The degradation of n-alkanes and polycyclic aromatic hydrocarbons with high molecular weight was accelerated, and denaturing gradient gel electrophoresis showed that the microbial community close to the air-cathode was substantially stimulated by the induced current, especially the hydrocarbon degrading bacteria Alcanivorax. The bioelectrochemical stimulation imposed a selective pressure on the microbial community of anodes, including that far from the cathode. These results suggested that sand amendment can be an effective approach for soil conditioning that will enhances the bioelectrochemical removal of hydrocarbons in contaminated soils. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Potential and real ecological threat of heavy metals in contaminated soils

    NASA Astrophysics Data System (ADS)

    Motuzova, Galina; Barsova, Natalia; Makarichev, Ivan; Karpova, Elena

    2013-04-01

    organisms. Within the last 20-40 years a bulk of information has been accumulating to study the impact of technogenic sources on the HM content in soils and the ratio between their compounds. They serve as evidence that in the contaminated soils the total content of HM is several orders (2-3) higher than that in soils of natural landscapes. Based upon a comprehensive analysis of data obtained in field and laboratory it is possible to speak about following differences in soils of natural and technogenic landscapes. (1) The total content of HM in contaminated soils reveals weak connection with their content in soil-forming rocks being depended on technological and landscape-geochemical conditions. (2) A share of mobile forms of HM from their total content increases in comparison to that in natural soils, what is associated with soil contamination and even toxicity, because they can be easily taken up by plants and other living organisms. (3) The surplus of HM in soils leads to degradation of the most important properties so vital for soil fertility (acid base saturation, ion exchange capacity, the humus status, absorbing capacity and others). The enhanced knowledge of soil chemical properties which are subject to contamination by HM, regularities in sorption of heavy metals bond to soil components, the composition of compounds formed by soil with heavy metals allows forecasting the real ecological threat of landscape contamination with HM. The indices of the foregoing soil chemical properties serve as a basis for application of current technologies for soil remediation from HM. Acknowledgments. This work was supported by the Russian Found of Basic Researches (projects no. 06-05-48894, 09-05-00575, 11-05-90351)

  4. Effects of soil amendment with different carbon sources and other factors on the bioremediation of an aged PAH-contaminated soil.

    PubMed

    Teng, Ying; Luo, Yongming; Ping, Lifeng; Zou, Dexun; Li, Zhengao; Christie, Peter

    2010-04-01

    Carbon supplementation, soil moisture and soil aeration are believed to enhance in situ bioremediation of PAH-contaminated soils by stimulating the growth of indigenous microorganisms. However, the effects of added carbon and nitrogen together with soil moisture and soil aeration on the dissipation of PAHs and on associated microbial counts have yet to be fully assessed. In this study the effects on bioremediation of carbon source, carbon-to-nitrogen ratio, soil moisture and aeration on an aged PAH-contaminated agricultural soil were studied in microcosms over a 90-day period. Additions of starch, glucose and sodium succinate increased soil bacterial and fungal counts and accelerated the dissipation of phenanthrene and benzo(a)pyrene in soil. Decreases in phenanthrene and benzo(a)pyrene concentrations were effective in soil supplemented with glucose and sodium succinate (both 0.2 g C kg(-1) dry soil) and starch (1.0 g C kg(-1) dry soil). The bioremediation effect at a C/N ratio of 10:1 was significantly higher (P < 0.05) than at a C/N of either 25:1 or 40:1. Soil microbial counts and PAH dissipation were lower in the submerged soil but soil aeration increased bacterial and fungal counts, enhanced indigenous microbial metabolic activities, and accelerated the natural degradation of phenanthrene and benzo(a)pyrene. The results suggest that optimizing carbon source, C/N ratio, soil moisture and aeration conditions may be a feasible remediation strategy in certain PAH contaminated soils with large active microbial populations.

  5. Efficacy of indigenous soil microbes in arsenic mitigation from contaminated alluvial soil of India.

    PubMed

    Majumder, Aparajita; Bhattacharyya, Kallol; Kole, S C; Ghosh, Sagarmoy

    2013-08-01

    Selected arsenic-volatilizing indigenous soil bacteria were isolated and their ability to form volatile arsenicals from toxic inorganic arsenic was assessed. Approximately 37 % of AsIII (under aerobic conditions) and 30 % AsV (under anaerobic conditions) were volatilized by new bacterial isolates in 3 days. In contrast to genetically modified organism, indigenous soil bacteria was capable of removing 16 % of arsenic from contaminated soil during 60 days incubation period while applied with a low-cost organic nutrient supplement (farm yard manure).

  6. Biochar based remediation of water and soil contaminated by phenanthrene and pentachlorophenol.

    PubMed

    Rao, Maria A; Di Rauso Simeone, Giuseppe; Scelza, Rosalia; Conte, Pellegrino

    2017-11-01

    Phenanthrene (Phe) and pentachlorophenol (PCP) are classified as persistent organic pollutants and represent serious concern for the environment as they are toxic and ubiquitous. Biochar based remediation is an emerging technology used in water and soil contamination. In this study we used poplar (BP) and conifer (BC) biochars to remediate water and soil contaminated by Phe and PCP. BP and BC were able to remove completely either Phe or PCP from contaminated water within one to three days. When biochar was confined in a porous membrane, BC and BP maintained their sorption efficiency for several remediation cycles. However, in these conditions BC allowed faster Phe removal. In soil remediation experiments, addition of two biochar rates, i.e. 2.5 and 5 mg g -1 , strongly reduced Phe extractability (up to 2.7% of the initially added Phe with the larger BC dose). This was similar to the behavior observed when compost was applied in order to verify the role of soil organic matter in the fate of both contaminants. PCP extractability was reduced only up to 75% (in average) in all samples including those with compost amendment. Only larger amount of biochar (20 and 50 mg g -1 ) allowed reduction of the extractable PCP and nullified phytotoxicity of the contaminant. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Contamination of soils and groundwater with new organic micropollutants: A review

    NASA Astrophysics Data System (ADS)

    Vodyanitskii, Yu. N.; Yakovlev, A. S.

    2016-05-01

    The input of organic micro- and nanopollutants to the environment has grown in recent years. This vast class of substances is referred to as emerging micropollutants, and includes organic chemicals of industrial, agricultural, and municipal provenance. There are three main sources of emerging pollutants coming to the environment, i.e., (1) upon soil fertilization with sewage and sewage sludge; (2) soil irrigation with reclaimed wastewater and (3) due to filtration from municipal landfills of solid wastes. These pollutants contaminate soil, affect its inhabitants; they are also consumed by plants and penetrate to the groundwater. The pharmaceuticals most strongly affect the biota (microorganisms, earthworms, etc.). The response of microorganisms in the contaminated soil is controlled not only by the composition and the number of emerging pollutants but also by the geochemical environment.

  8. [Biological treatments for contaminated soils: hydrocarbon contamination. Fungal applications in bioremediation treatment].

    PubMed

    Martín Moreno, Carmen; González Becerra, Aldo; Blanco Santos, María José

    2004-09-01

    Bioremediation is a spontaneous or controlled process in which biological, mainly microbiological, methods are used to degrade or transform contaminants to non or less toxic products, reducing the environmental pollution. The most important parameters to define a contaminated site are: biodegradability, contaminant distribution, lixiviation grade, chemical reactivity of the contaminants, soil type and properties, oxygen availability and occurrence of inhibitory substances. Biological treatments of organic contaminations are based on the degradative abilities of the microorganisms. Therefore the knowledge on the physiology and ecology of the biological species or consortia involved as well as the characteristics of the polluted sites are decisive factors to select an adequate biorremediation protocol. Basidiomycetes which cause white rot decay of wood are able to degrade lignin and a variety of environmentally persistent pollutants. Thus, white rot fungi and their enzymes are thought to be useful not only in some industrial process like biopulping and biobleaching but also in bioremediation. This paper provides a review of different aspects of bioremediation technologies and recent advances on ligninolytic metabolism research.

  9. [Microwave thermal remediation of soil contaminated with crude oil enhanced by granular activated carbon].

    PubMed

    Li, Da-Wei; Zhang, Yao-Bin; Quan, Xie; Zhao, Ya-Zhi

    2009-02-15

    The advantage of rapid, selective and simultaneous heating of microwave heating technology was taken to remediate the crude oil-contaminated soil rapidly and to recover the oil contaminant efficiently. The contaminated soil was processed in the microwave field with addition of granular activated carbon (GAC), which was used as strong microwave absorber to enhance microwave heating of the soil mixture to remove the oil contaminant and recover it by a condensation system. The influences of some process parameters on the removal of the oil contaminant and the oil recovery in the remediation process were investigated. The results revealed that, under the condition of 10.0% GAC, 800 W microwave power, 0.08 MPa absolute pressure and 150 mL x min(-1) carrier gas (N2) flow-rate, more than 99% oil removal could be obtained within 15 min using this microwave thermal remediation enhanced by GAC; at the same time, about 91% of the oil contaminant could be recovered without significant changes in chemical composition. In addition, the experiment results showed that GAC can be reused in enhancing microwave heating of soil without changing its enhancement efficiency obviously.

  10. Metal availability, soil nutrient, and enzyme activity in response to application of organic amendments in Cd-contaminated soil.

    PubMed

    Yang, Zhanbiao; Liu, Lixia; Lv, Yanfeng; Cheng, Zhang; Xu, Xiaoxun; Xian, Junren; Zhu, Xuemei; Yang, Yuanxiang

    2018-01-01

    The study investigated the effects of organic amendments: green tea amendment (GTA) and oil cake amendment (OCA) on Cd bioavailability, soil nutrients, and soil enzyme activity in Cd-contaminated soil. The amendments were added to the soil at the doses of 1, 3, and 5% and were incubated for 45 days. Then, pakchoi cabbage was planted to test the remediation effect of the above two organic amendments. The diethylenetriaminepentaacetic acid (DTPA)-extractable Cd in GTA and OCA treatments was reduced by 14.69-27.51 and 13.75-68.77%, respectively, compared to no amendment-applied treatment. The application of GTA and OCA notably decreased the proportion of exchangeable fraction of Cd, but increased the percentage of oxide and organic-bound fraction of Cd, thereby suppressing the uptake by pakchoi cabbage. Cd concentration of aboveground parts decreased by 8.21-18.05 and 7.77-35.89% in GTA and OCA treatments, respectively. Relative to the no amendment-applied treatment, both GTA and OCA had enhanced soil nutrients and enzyme activities largely. Redundancy analysis showed that organic matter, total P, available N, and DTPA-extractable Cd significantly affected the enzyme activities. Furthermore, the application of OCA at the dose of 5% was more effective in reducing bioavailable Cd, enhancing soil available nutrients and urease and catalase activities in contaminated soil. These results indicated that oil cake should be used to immobilize metal and improve fertility and quality of Cd-contaminated soil.

  11. Degradation of Total Petroleum Hydrocarbon (TPH) in Contaminated Soil Using Bacillus pumilus MVSV3.

    PubMed

    Varma, Surendra Sheeba; Lakshmi, Mahalingam Brinda; Rajagopal, Perumalsam; Velan, Manickam

    2017-01-01

     A study on bioremediation of soil contaminated with petroleum sludge was performed using Bacillus pumilus/MVSV3 (Accession number JN089707). In this study, 5 kg of agricultural soil was mixed well with 5% oil sludge and fertilizers containing nitrogen, phosphorus and potassium (N:P:K). The treatment resulted in 97% removal of total petroleum hydrocarbon (TPH) in 122 d in bacteria mixed contaminated soil when compared to 12% removal of TPH in uninoculated contaminated soil. The population of the microorganism remained stable after introduced into the oil environment. The physical and chemical parameters of the soil mixed with sludge showed variation indicating improvement and the pH level decreased during the experiment period. Elemental analysis and Gas Chromatography-Mass Spectroscopy (GC-MS) analysis revealed the bacterial ability to degrade oil sludge components. Growth experiments with Trigonellafoenumgraecum (Fenugreek) showed the applicability of bioremediated soil for the production.

  12. Development of provisions for oil contaminated soil neutralizing in the conditions of Siberia and the Arctic

    NASA Astrophysics Data System (ADS)

    Shtripling, L. O.; Kholkin, E. G.

    2017-08-01

    Siberia and the Arctic zone of the Russian Federation occupy a large area of the country and they differ from other regions in special climatic conditions, in particular, a long period of freezing temperatures and relatively poor infrastructure. The main problem of neutralizing soils contaminated with oil products in conditions of negative ambient temperature is that the contaminated soil is in a frozen state, and it prevents the normal course of neutralization process, so additional energy is required for preparing the soil. There is proposed a technology adapted to the conditions of Siberia and the Arctic for the operational elimination of emergency situations consequences accompanied with oil spills. The technology for neutralizing soils contaminated with petroleum products is based on the encapsulation of a pollutant (reagent capsulation technology) using an alkaline calcium-based reagent. Powdered building quicklime is used as a reagent, and it is a product of roasting carbonate rocks or a mixture of this product with mineral additives (calcium oxide). The encapsulated material obtained as a result of neutralizing soils contaminated with petroleum products is resistant to natural and man-made factors such as moisture, temperature fluctuations, acid rain and high pressure. Energy use from the chemical detoxification exothermic process of soils contaminated with petroleum products in combination with the forced supply of carbon dioxide to the neutralization zone during the formation of a shell from calcium carbonate on the surface of the pollutant makes it possible to neutralize soils contaminated with oil products in the extreme climatic conditions of the Arctic using reagent Encapsulation. The principle of equipment operation that allows neutralizing soils contaminated with petroleum products in the natural and climatic conditions of the Arctic using reagent capsulation technology has been described. The results of experimental studies have been presented that

  13. Phytoremediation of soils contaminated with toxic elements and radionuclides

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cornish, J.E.; Goldberg, W.C.; Levine, R.S.

    1995-12-31

    At many US Department of Energy (US DOE) facilities and other sites, surface soils over relatively large areas are contaminated with heavy metals, radionuclides, and other toxic elements, often at only a relatively small factor above regulatory action levels. Cleanup of such sites presents major challenges, because currently available soil remediation technologies can be very expensive. In response, the US DOE`s Office of Technology Development, through the Western Environmental Technology Office, is sponsoring research in the area of phytoremediation. Phytoremediation is an emerging technology that uses higher plants to transfer toxic elements and radionuclides from surface soils into aboveground biomass.more » Some plants, termed hyperaccumulators, take up toxic elements in substantial amounts, resulting in concentrations in aboveground biomass over 100 times those observed with conventional plants. After growth, the plant biomass is harvested, and the toxic elements are concentrated and reclaimed or disposed of. As growing, harvesting, and processing plant biomass is relatively inexpensive, phytoremediation can be a low-cost technology for remediation of extensive areas having lightly to moderately contaminated soils. This paper reviews the potential of hyper- and moderate accumulator plants in soil remediation, provides some comparative cost estimates, and outlines ongoing work initiated by the US DOE.« less

  14. Direct and indirect effects of biochar on the mobility of metals and nutrients in contaminated soils: a two-column leaching experiment

    NASA Astrophysics Data System (ADS)

    Rees, Frédéric; Simonnot, Marie-Odile; Morel, Jean-Louis

    2014-05-01

    Biochar has been claimed to be not only a promising carbon sequestration or fertilizing agent in soils but also a high capacity sorbent, of particular interest for the management of contaminated soils. Several studies have described its positive effects on the mobility of different potentially toxic elements in soils, but many doubts remain about the underlying mechanisms. In particular, the distinction between the actual adsorption of elements on biochar and their biochar-induced retention on soil particles is often impossible to achieve. We studied here the dynamic interactions between one biochar produced at 450°C from a mix of hard wood and soft wood, and two soils contaminated by Cd, Pb and Zn which were sampled near a smelter and only differed from their pH. In order to distinguish between the actual immobilization of elements on biochar and their modified retention on soil particles, we developed a two-column leaching experiment using calcium nitrate as the initial leaching solution. The first column was filled with one of the two soils, and was linked in a closed loop with the second column containing a mass of pure biochar equivalent to 10% of the soil mass. The leaching solution circulated first in the soil column, then through the biochar column and again in the soil column and so on, so that it became progressively equilibrated with both soil and biochar. Each experiment lasted for 12 days at a flow rate of 1 mL/min. The pH and electrical conductivity of the leaching solution was continuously monitored at the outlet of the biochar column, and samples of the leaching solution were regularly taken for further analysis, both before and after having passed each of the columns. Our results show that the chemical equilibrium between soil and biochar was obtained in a short time for major elements such as Na, K and Mg, whereas for heavy metals and other elements as well as for pH and dissolved carbon, the equilibrium was still not reached at the end of the

  15. Enzymatic bioremediation of polyaromatic hydrocarbons by fungal consortia enriched from petroleum contaminated soil and oil seeds.

    PubMed

    Balaji, V; Arulazhagan, P; Ebenezer, P

    2014-05-01

    The present study focuses on fungal strains capable of secreting extracellular enzymes by utilizing hydrocarbons present in the contaminated soil. Fungal strains were enriched from petroleum hydrocarbons contaminated soil samples collected from Chennai city, India. The potential fungi were isolated and screened for their enzyme secretion such as lipase, laccase, peroxidase and protease and also evaluated fungal enzyme mediated PAHs degradation. Total, 21 potential PAHs degrading fungi were isolated from PAHs contaminated soil, which belongs to 9 genera such as Aspergillus, Curvularia, Drechslera, Fusarium, Lasiodiplodia, Mucor Penicillium, Rhizopus, Trichoderma, and two oilseed-associated fungal genera such as Colletotrichum and Lasiodiplodia were used to test their efficacy in degradation of PAHs in polluted soil. Maximum lipase production was obtained with P. chrysogenum, M. racemosus and L. theobromae VBE1 under optimized cultural condition, which utilized PAHs in contaminated soil as sole carbon source. Fungal strains, P. chrysogenum, M. racemosus and L. theobromae VBE1, as consortia, used in the present study were capable of degrading branched alkane isoprenoids such as pristine (C17) and pyrene (C18) present in PAHs contaminated soil with high lipase production. The fungal consortia acts as potential candidate for bioremediation of PAHs contaminated environments.

  16. [The status of soil contamination in areas of northern and northwestern Bohemia affected by pollution].

    PubMed

    Podlesáková, E; Nĕmecek, J; Vácha, R

    1999-10-20

    A regional study of soil contamination in North and Northwest immission-impacted Bohemian regions present the results of the assessment of soil loads of agricultural soils by hazardous trace elements and organic xenobiotic substances. The evaluation is based on the exceeding of background values of contaminants (upper limit of their variability). Two forms of soil loads by trace elements are differentiated, the anthropogenic and geogenic one. They occur simultaneously on the territory under study. Geogenic "loads" prevail (basalts, metallogenic zones). Anthropogenic contamination by both hazardous elements and organic xenobiotic substances occurs only in some parts of these severely immission-impacted regions.

  17. De-icing salt contamination reduces urban tree performance in structural soil cells.

    PubMed

    Ordóñez-Barona, Camilo; Sabetski, Vadim; Millward, Andrew A; Steenberg, James

    2018-03-01

    Salts used for de-icing roads and sidewalks in northern climates can have a significant impact on water quality and vegetation. Sub-surface engineering systems, such as structural soil cells, can regulate water runoff and pollutants, and provide the necessary soil volume and irrigation to grow trees. However, the ability of such systems to manage de-icing salt contamination, and the impact of this contamination on the trees growing in them, have not been evaluated. We report on an field investigation of de-icing salt contamination in structural cells in two street-revitalization projects in Toronto, Canada, and the impact of this contamination on tree performance. We analyzed soil chemistry and collected tree attributes; these data were examined together to understand the effect of salinity on tree mortality rates and foliar condition. Data collected from continuous soil salinity loggers from April to June for one of the two sites were used to determine whether there was a long-term accumulation of salts in the soils. Results for both sites indicate that both sites displayed high salinity and alkalinity, with levels elevated beyond those suggested before those reported to cause negative tree effects. For one site, trees that were alive and trees that had a better foliar condition had significantly lower levels of soil salinity and alkalinity than other trees. High salinity and alkalinity in the soil were also associated with lower nutrient levels for both sites. Although tests for salinity accumulation in the soils of one site were negative, a longer monitoring of the soil conditions within the soil cells is warranted. Despite structural cells being increasingly utilized for their dual role in storm-water management and tree establishment, there may be a considerable trade-off between storm-water management and urban-forest function in northern climates where de-icing salt application continues to be commonplace. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Improving the phytoremediation of heavy metals contaminated soil by use of sewage sludge.

    PubMed

    Placek, Agnieszka; Grobelak, Anna; Kacprzak, Malgorzata

    2016-01-01

    Sewage sludge, in particular from the food industry, is characterized by fertilizing properties, due to the high content of organic matter and nutrients. The application of sewage sludge causes an improvement of soil parameters as well as increase in cation exchange capacity, and thus stronger binding of cations in the soil environment, which involves the immobilization of nutrients and greater resistance to contamination. In a field experiment sewage sludge has been used as an additive to the soil supporting the phytoremediation process of land contaminated with heavy metals (Cd, Zn, and Pb) using trees species: Scots pine (Pinus silvestris L.), Norway spruce (Picea abies L.), and oak (Quercus robur L.). The aim of the research was to determine how the application of sewage sludge into the soil surface improves the phytoremediation process. The conducted field experiment demonstrated that selected trees like Scots pine and Norway spruce, because of its excellent adaptability, can be used in the remediation of soil. Oak should not be used in the phytoremediation process of soils contaminated with high concentrations of trace elements in the soil, because a significant amount of heavy metals was accumulated in the leaves of oak causing a risk of recontamination.

  19. Relative Bioavailability and Bioaccessability and Speciation of Arsenic in Contaminated Soils

    EPA Science Inventory

    Background: Assessment of soil arsenic (As) bioavailability may profoundly affect the extent of remediation required at contaminated sites by improving human exposure estimates. Because small adjustments in soil As bioavailability estimates can significantly alter risk assessment...

  20. Earthworm Comet Assay for Assessing the Risk of Weathered Petroleum Hydrocarbon Contaminated Soils: Need to Look Further than Target Contaminants.

    PubMed

    Ramadass, Kavitha; Palanisami, Thavamani; Smith, Euan; Mayilswami, Srinithi; Megharaj, Mallavarapu; Naidu, Ravi

    2016-11-01

    Earthworm toxicity assays contribute to ecological risk assessment and consequently standard toxicological endpoints, such as mortality and reproduction, are regularly estimated. These endpoints are not enough to better understand the mechanism of toxic pollutants. We employed an additional endpoint in the earthworm Eisenia andrei to estimate the pollutant-induced stress. In this study, comet assay was used as an additional endpoint to evaluate the genotoxicity of weathered hydrocarbon contaminated soils containing 520 to 1450 mg hydrocarbons kg -1 soil. Results showed that significantly higher DNA damage levels (two to sixfold higher) in earthworms exposed to hydrocarbon impacted soils. Interestingly, hydrocarbons levels in the tested soils were well below site-specific screening guideline values. In order to explore the reasons for observed toxicity, the contaminated soils were leached with rainwater and subjected to earthworm tests, including the comet assay, which showed no DNA damage. Soluble hydrocarbon fractions were not found originally in the soils and hence no hydrocarbons leached out during soil leaching. The soil leachate's Electrical Conductivity (EC) decreased from an average of 1665 ± 147 to 204 ± 20 µS cm -1 . Decreased EC is due to the loss of sodium, magnesium, calcium, and sulphate. The leachate experiment demonstrated that elevated salinity might cause the toxicity and not the weathered hydrocarbons. Soil leaching removed the toxicity, which is substantiated by the comet assay and soil leachate analysis data. The implication is that earthworm comet assay can be included in future eco (geno) toxicology studies to assess accurately the risk of contaminated soils.

  1. Prediction of the effects of soil-based countermeasures on soil solution chemistry of soils contaminated with radiocesium using the hydrogeochemical code PHREEQC.

    PubMed

    Hormann, Volker; Kirchner, Gerald

    2002-04-22

    For agriculturally used areas, which are contaminated by the debris from a nuclear accident, the use of chemical amendmends (e.g. potassium chloride and lime) is among the most common soil-based countermeasures. These countermeasures are intended to reduce the plant uptake of radionuclides (mainly 137Cs and 90Sr) by competitive inhibition by chemically similar ions. So far, the impacts of countermeasures on soil solution composition - and thus, their effectiveness - have almost exclusively been established experimentally, since they depend on mineral composition and chemical characteristics of the soil affected. In this study, which focuses on caesium contamination, the well-established code PHREEQC was used as a geochemical model to calculate the changes in the ionic compositions of soil solutions, which result from the application of potassium or ammonium in batch equilibrium experiments. The simple ion exchange model used by PHREEQC was improved by taking into account selective sorption of Cs+, NH4+ and K+ by clay minerals. Calculations were performed with three different initial soil solution compositions, corresponding to particular soil types (loam, sand, peat). For loamy and sandy soils, our calculational results agree well with experimental data reported by Nisbet (Effectiveness of soil-based countermeasures six months and one year after contamination of five diverse soil types with caesium-134 and strontium-90. Contract Report NRPB-M546, National Radiation Protection Board, Chilton, 1995.). For peat, discrepancies were found indicating that for organic soils a reliable set of exchange constants of the relevant cations still has to be determined experimentally. For cesium, however, these discrepancies almost disappeared if selective sites were assumed to be inaccessible. Additionally, results of sensitivity analyses are presented by which the influence of the main soil parameters on Cs+ concentrations in solution after soil treatment has been systematically

  2. [Application of ICP-MS in evaluating element contamination in soils].

    PubMed

    Wu, Ying-juan; Chen, Yong-heng; Yang, Chun-xia; Chang, Xiang-yang

    2008-12-01

    The Yunfu pyrite was the second biggest pyrite bed in the world. Plants using industrial ore of the Yunfu pyrite are distributed in many sections across the country. In the present paper, elements V, Cr, Co, Cu, Zn, Mo, Cd, Sb, Rb and Cs in soil profiles in slag disposing area of a sulfuric acid plant using industrial ore of theYunfu pyrite were studied. A method for simultaneously determination of metals and some reference elements in soils by ICP-MS was developed. The correlations between the metals and their reference elements were fast found. Enrichment factors were applied for evaluating the degree of soil contamination, and the problem about choosing contamination elements background values was pointed out. The results indicated that element V showed apparent and serious pollution, The Co showed middle degree pollution, and there has been a trend of apparent pollution. The Cr, Mo and Cd showed pollution between light degree and middle degree. The Zn and Sb showed light degree pollution, and there was a latent trend of middle degree pollution. The Cu showed light degree pollution. The high enrichment points of the V and the Cr were observed in the upper part (4.0-10.5 cm) and deep part of soil profiles (44.0-75.5 cm). Those of Co and Mo were found in the surface of soil profiles (0-5.0 cm), middle-upper part (9.5-10.5 cm) and middle part (29.5-46.0 cm), while those of Cd and Cu occurred just in the middle of soil profiles (29.5-46.0 cm). The formation of highly enrichment points of contamination elements in the soil profiles was the result of leaching and accumulating effect of the metals released from slag and the residual metals of highly weathered red soils. Most of pollution of V in the soil was contributed by the V in soil bed. Part of the V pollution in the soil was supplied by leaching and accumulating effect of the V which came from catalyst with lost activity in sulfuric acid production volatilizing into slag.

  3. PCDD/F formation during thermal desorption of p,p'-DDT contaminated soil.

    PubMed

    Zhao, Zhonghua; Ni, Mingjiang; Li, Xiaodong; Buekens, Alfons; Yan, Jianhua

    2017-05-01

    Thermal treatment of polychlorinated biphenyls (PCB) contaminated soil was shown in earlier work to generate polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF). In this study, the PCDD/F were studied arising during the remediation of p,p'-DDT contaminated soil by thermal desorption. Three kinds of soil (sandy, clayey and lateritic soil) were tested to investigate the effect of soil texture on PCDD/F formation. Those soils were artificially polluted with p,p'-DDT, obtaining a concentration level of 100 mg/kg. Thermal desorption experiments were conducted for 10 min at 300 °C in an air atmosphere. The total concentration of PCDD/F generated for three soils were 331, 803 and 865 ng/kg, respectively, and TeCDD and TeCDF were dominant among all PCDD/F congeners. After thermal desorption, the total amount of PCDD/F generated both in soil and in off-gas correlated positively with the amount of DDT added to soil. In addition, a possible pathway of the formation of PCDD/F was presented.

  4. RELEASE OF CHEMICALS FROM CONTAMINATED SOILS. (R822721C529)

    EPA Science Inventory

    At sites that contain contaminated soils, there can be questions about the magnitude of risk posed by the chemicals in the soils and about the cleanup levels that should be achieved. Knowledge about the rate of release of chemicals is important to answers to such questions. Th...

  5. A laboratory treatability study on RDX-contaminated soil from the Iowa Army Ammunition Plant, Burlington, Iowa.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Boopathy, R.; Manning, J. F.; Environmental Research

    2000-03-01

    Soil in certain areas of the Iowa Army Ammunition Plant in Burlington, Iowa, was contaminated with hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). A laboratory treatability study was conducted to examine the ability of native soil bacteria present in the contaminated site to degrade RDX. The results indicated that RDX can be removed effectively from the soil by native soil bacteria through a co-metabolic process. Molasses, identified as an effective cosubstrate, is inexpensive, and this factor makes the treatment system cost effective. The successful operation of aerobic-anoxic soil-slurry reactors in batch mode with RDX-contaminated soil showed that the technology can be scaled up for fieldmore » demonstration. The RDX concentration in the contaminated soil was decreased by 98% after 4 months of reactor operation. The advantage of the slurry reactor is the simplicity of its operation. The method needs only mixing and the addition of molasses as cosubstrate.« less

  6. Remediation of uranium contaminated soils with bicarbonate extraction and microbial U(VI) reduction

    USGS Publications Warehouse

    Philips , Elizabeth J.P.; Landa, Edward R.; Lovely, Derek R.

    1995-01-01

    A process for concentrating uranium from contaminated soils in which the uranium is first extracted with bicarbonate and then the extracted uranium is precipitated with U(VI)-reducing microorganisms was evaluated for a variety of uranuum-contaminated soils. Bicarbonate (100 mM) extracted 20–94% of the uranium that was extracted with nitric acid. The U(VI)-reducing microorganism,Desulfovibrio desulfuricans reduced the U(VI) to U(IV) in the bicarbonate extracts. In some instances unidentified dissolved extracted components, presumably organics, gave the extract a yellow color and inhibited U(VI) reduction and/or the precipitation of U(IV). Removal of the dissolved yellow material with the addition of hydrogen peroxide alleviated this inhibition. These results demonstrate that bicarbonate extraction of uranium from soil followed by microbial U(VI) reduction might be an effective mechanism for concentrating uranium from some contaminated soils.

  7. Stabilization of Pb and Cd contaminated soils and soil quality improvements using waste oyster shells.

    PubMed

    Ok, Yong Sik; Lim, Jung Eun; Moon, Deok Hyun

    2011-02-01

    Large amounts of oyster shells are produced as a by-product of shellfish farming in coastal regions without beneficial use options. Accordingly, this study was conducted to evaluate the potential for the use of waste oyster shells (WOS) containing a high amount of CaCO₃ to improve soil quality and to stabilize heavy metals in soil. To accomplish this, an incubation experiment was conducted to evaluate the ability of the addition of 1-5 wt% WOS to stabilize the Pb (total 1,246 mg/kg) and Cd (total 17 mg/kg) in a contaminated soil. The effectiveness of the WOS treatments was evaluated using various single extraction techniques. Soil amended with WOS was cured for 30 days complied with the Korean Standard Test method (0.1 M·HCl extraction). The Pb and Cd concentrations were less than the Korean warning and countermeasure standards following treatment with 5 wt% WOS. Moreover, the concentrations of Cd were greatly reduced in response to WOS treatment following extraction using 0.01 M·CaCl₂, which is strongly associated with phytoavailability. Furthermore, the soil pH and exchangeable Ca increased significantly in response to WOS treatment. Taken together, the results of this study indicated that WOS amendments improved soil quality and stabilized Pb and Cd in contaminated soil. However, extraction with 0.43 M·CH₃ COOH revealed that remobilization of heavy metals can occur when the soil reaches an acidic condition.

  8. Surfactant-enhanced flushing enhances colloid transport and alters macroporosity in diesel-contaminated soil.

    PubMed

    Guan, Zhuo; Tang, Xiang-Yu; Nishimura, Taku; Katou, Hidetaka; Liu, Hui-Yun; Qing, Jing

    2018-02-01

    Soil contamination by diesel has been often reported as a result of accidental spillage, leakage and inappropriate use. Surfactant-enhanced soil flushing is a common remediation technique for soils contaminated by hydrophobic organic chemicals. In this study, soil flushing with linear alkylbenzene sulfonates (LAS, an anionic surfactant) was conducted for intact columns (15cm in diameter and 12cm in length) of diesel-contaminated farmland purple soil aged for one year in the field. Dynamics of colloid concentration in column outflow during flushing, diesel removal rate and resulting soil macroporosity change by flushing were analyzed. Removal rate of n-alkanes (representing the diesel) varied with the depth of the topsoil in the range of 14%-96% while the n-alkanes present at low concentrations in the subsoil were completely removed by LAS-enhanced flushing. Much higher colloid concentrations and larger colloid sizes were observed during LAS flushing in column outflow compared to water flushing. The X-ray micro-computed tomography analysis of flushed and unflushed soil cores showed that the proportion of fine macropores (30-250μm in diameter) was reduced significantly by LAS flushing treatment. This phenomenon can be attributed to enhanced clogging of fine macropores by colloids which exhibited higher concentration due to better dispersion by LAS. It can be inferred from this study that the application of LAS-enhanced flushing technique in the purple soil region should be cautious regarding the possibility of rapid colloid-associated contaminant transport via preferential pathways in the subsurface and the clogging of water-conducting soil pores. Copyright © 2017. Published by Elsevier B.V.

  9. Uptake of aromatic arsenicals from soil contaminated with diphenylarsinic acid by rice.

    PubMed

    Arao, Tomohito; Maejima, Yuji; Baba, Koji

    2009-02-15

    Chemical warfare agents containing aromatic arsenicals (AAs) such as Clark I (diphenylchloroarsine) are well-known, as is the risk of leakage from such munitions into the environment. We investigated the uptake of AAs in agricultural soils by rice. Methylphenylarsinic acid (MPAA) was detected in brown rice grown in contaminated soil. Dimethylphenylarsine oxide (DMPAO) and methyldiphenylarsine oxide (MDPAO) were detected in the straw but not in the grains grown in the contaminated soil. Inthe contaminated soil, phenylarsonic acid (PAA) and MPAA concentrations decreased and DMPAO concentration increased under the flooded conditions; however, their concentrations remained unchanged underthe upland conditions. DMPAO was detected in the straw of the rice grown in PAA- or MPAA-amended soil but was not detected in that grown in a PAA- or MPAA-added solution culture. MDPAO was detected in the straw of the rice grown in diphenylarsinic acid (DPAA)-amended soil but was not detected in that grown in a DPAA-added solution culture. Thus, MPAA and DPAA were methylated not in the rice plant but in the soil under the flooded conditions. Dephenylated products were detected in the straw grown in AA-added solution cultures, but demethylated products were not detected. DMPAO and MDPAO absorbed by the shoots were retained, and MPAA and DPAA absorbed by the shoots were translocated to the grains more easily than other AAs.

  10. AIR EMISSIONS FROM THE TREATMENT OF SOILS CONTAMINATED WITH PETROLEUM FUELS AND OTHER SUBSTANCES

    EPA Science Inventory

    The report updates a 1992 report that summarizes available information on air emissions from the treatment of soils contaminated with fuels. Soils contaminated by leaks or spills of fuel products, such as gasoline or jet fuel, are a nationwide concern. Air emissions during remedi...

  11. Impact of clay mineral on air oxidation of PAH-contaminated soils.

    PubMed

    Biache, Coralie; Kouadio, Olivier; Lorgeoux, Catherine; Faure, Pierre

    2014-09-01

    This work investigated the impact of a clay mineral (bentonite) on the air oxidation of the solvent extractable organic matters (EOMs) and the PAHs from contaminated soils. EOMs were isolated from two coking plant soils and mixed with silica sand or bentonite. These samples, as well as raw soils and bentonite/soil mixtures, were oxidized in air at 60 and 100 °C for 160 days. Mineralization was followed by measuring the CO2 produced over the experiments. EOM, polycyclic aromatic compound (PAC), including PAH, contents were also determined. Oxidation led to a decrease in EOM contents and PAH concentrations, these diminutions were enhanced by the presence of bentonite. Transfer of carbon from EOM to insoluble organic matter pointed out a condensation phenomenon leading to a stabilization of the contamination. Higher mineralization rates, observed during the oxidation of the soil/bentonite mixtures, seem to indicate that this clay mineral had a positive influence on the transformation of PAC into CO2.

  12. Mobility and bio-availability of heavy metals in anthropogenically contaminated alluvial (deluvial) meadow soils (EUTRIC FLUVISOLS)

    NASA Astrophysics Data System (ADS)

    Dinev, Nikolai; Hristova, Mariana; Tzolova, Venera

    2015-04-01

    The total content of heavy metals is not sufficient to assess the pollution and the risk for environment as it does not provide information for the type and solubility of heavy metals' compounds in soils. The purpose was to study and determine the mobility of heavy metals in anthropogenically contaminated alluvial (delluvial) meadow soils spread around the non-ferrous plant near the town of Asenovgrad in view of risk assessment for environment pollution. Soil samples from monitoring network (1x1 km) was used. The sequential extraction procedure described by Zein and Brummer (1989) was applied. Results showed that the easily mobilizable cadmium compounds predominate in both contaminated and not contaminated soils. The stable form of copper (associated with silicate minerals, carbonates or amorphous and crystalline oxide compounds) predominates only in non polluted soils and reviles the risk of the environment contamination. Lead spreads and accumulates as highly soluble (mobile) compounds and between 72.3 and 99.6 percent of the total lead is bioavailable in soils. The procedure is very suitable for studying the mobility of technogenic lead and copper in alluvial soils with neutral medium reaction and in particular at the high levels of cadmium contamination. In soils with alkaline reaction - polluted and unpolluted the error of analysis increases for all studied elements.

  13. Erosion and Soil Contamination Control Using Coconut Flakes And Plantation Of Centella Asiatica And Chrysopogon Zizanioides

    NASA Astrophysics Data System (ADS)

    Roslan, Rasyikin; Che Omar, Rohayu; Nor Zuliana Baharuddin, Intan; Zulkarnain, M. S.; Hanafiah, M. I. M.

    2016-11-01

    Land degradation in Malaysia due to water erosion and water logging cause of loss of organic matter, biodiversity and slope instability but also land are contaminated with heavy metals. Various alternative such as physical remediation are use but it not showing the sustainability in term of environmental sustainable. Due to that, erosion and soil contamination control using coconut flakes and plantation of Centella asiatica and Chrysopogon zizanioides are use as alternative approach for aid of sophisticated green technology known as phytoremediation and mycoremediation. Soil from cabonaceous phyllite located near to Equine Park, Sri Kembangan are use for monitoring the effect of phytoremediation and mycoremediation in reducing soil contamination and biotechnology for erosion control. Five laboratory scale prototypes were designed to monitor the effect of different proportion of coconut flakes i.e. 10%, 25%, 50% & 100% and plantation of Centella asiatica and Chrysopogon zizanioides to reduce the top soil from eroding and reduce the soil contamination. Prototype have been observe started from first week and ends after 12 weeks. Centella asiatica planted on 10% coconut flakes with 90% soil and Chrysopogon zizanioides planted on 25% coconut flakes with 75% soil are selected proportion to be used as phytoremediation and mycoremediation in reducing soil contamination and biotechnology for erosion control.

  14. Fluoride toxicity effects in onion (Allium cepa L.) grown in contaminated soils.

    PubMed

    Jha, S K; Nayak, A K; Sharma, Y K

    2009-07-01

    A pot experiment was carried out under controlled condition to investigate the accumulation, uptake and toxicity effects of fluoride (F) in onion (Allium cepa L.) grown on the soil contaminated by inorganic fluoride (NaF). Six different levels of soil contamination were used by adding 0, 100, 200, 400, 600 and 800 mg NaFkg(-1) to the soil. The F concentration in shoot, bulb and root varied between 16.3 and 109.1mg Fkg(-1), 15.8 and 54.3mg Fkg(-1) and 18.6 and 151.6 mg Fkg(-1), respectively. The visible symptoms of F toxicity in terms of tip burning and death of the plant was noticed in highly contaminated soils (>400mg NaFkg(-1) soil). The phyto-toxic threshold limit (LC(50)) in onion shoot was found to be 55 mg Fkg(-1), beyond which the biomass yield decreased by 50%. It was also inferred from the study that there is a partitioning of F in onion, with more accumulation in roots and shoots than in bulbs. The order of retention of fluoride in onion found to be roots>shoot>bulb.

  15. RETENTION OF LIQUID CONTAMINANTS IN LAYERED SOILS. (R825549C063)

    EPA Science Inventory

    Observations of organic contaminant liquids retained in layered soil profiles indicate contaminant saturations much greater than residual, where residual saturation would be expected, if one assumes a static distribution of fluid pressure. It is theorized that the increased re...

  16. RISK ASSESSMENT AND REMEDIATION OF SOILS CONTAMINATED BY MINING AND SMELTING OF LEAD, ZINC AND CADMIUM

    EPA Science Inventory

    Mining nd smelting of Pb, Zn and Cd ores have caused widespread soil contamination in many countries. In locations with severe soil contamination, and strongly acidic soil or mine waste, ecosystems are devastated. Research has shown that An phytotoxicity, Pb-induced phosphate def...

  17. Bioremediation of mercury: not properly exploited in contaminated soils!

    PubMed

    Mahbub, Khandaker Rayhan; Bahar, Md Mezbaul; Labbate, Maurizio; Krishnan, Kannan; Andrews, Stuart; Naidu, Ravi; Megharaj, Mallavarapu

    2017-02-01

    Contamination of land and water caused by heavy metal mercury (Hg) poses a serious threat to biota worldwide. The seriousness of toxicity of this neurotoxin is characterized by its ability to augment in food chains and bind to thiol groups in living tissue. Therefore, different remediation approaches have been implemented to rehabilitate Hg-contaminated sites. Bioremediation is considered as cheaper and greener technology than the conventional physico-chemical means. Large-scale use of Hg-volatilizing bacteria are used to clean up Hg-contaminated waters, but there is no such approach to remediate Hg-contaminated soils. This review focuses on recent uses of Hg-resistant bacteria in bioremediation of mercury-contaminated sites, limitation and advantages of this approach, and identifies the gaps in existing research.

  18. Antioxidative response of Lepidium sativum L. during assisted phytoremediation of Hg contaminated soil.

    PubMed

    Smolinska, Beata; Szczodrowska, Agnieszka

    2017-09-25

    In this study, Lepidium sativum L. was used in repeated phytoextraction processes to remove Hg from contaminated soil, assisted by combined use of compost and iodide (KI). L. sativum L. is sensitive to changes in environmental conditions and has been used in environmental tests. Its short vegetation period and ability to accumulate heavy metals make it suitable for use in repeated phytoextraction. The antioxidant enzymatic system of the plant (catalase (CAT), ascorbate peroxidase (APX), superoxide dismutase (SOD) and glutathione S-transferase (GST)) was analysed, to understand the effects of increasing Hg accumulation and translocation. Phytoextraction was repeated six times to decrease Hg contamination in soil, and the efficiency of each step was assessed. The results indicate that L. sativum L. is able to take up and accumulate Hg from contaminated soil. A corresponding increase in enzymatic antioxidants shows that the plant defence system is activated in response to Hg stress. Using compost and KI increases total Hg accumulation and translocation to the above-ground parts of L. sativum L. Repeating the process decreases Hg contamination in pot experiments in all variants of the process. The combined use of compost and KI during repeated phytoextraction increases the efficiency of Hg removal from contaminated soil. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Application of an in-situ soil sampler for assessing subsurface biogeochemical dynamics in a diesel-contaminated coastal site during soil flushing operations.

    PubMed

    Kwon, Man Jae; O'Loughlin, Edward J; Ham, Baknoon; Hwang, Yunho; Shim, Moojoon; Lee, Soonjae

    2018-01-15

    Subsurface biogeochemistry and contaminant dynamics during the remediation of diesel-contamination by in-situ soil flushing were investigated at a site located in a coastal region. An in-situ sampler containing diesel-contaminated soils separated into two size fractions (<0.063- and <2-mm) was utilized in two monitoring wells: DH1 (located close to the injection and extraction wells for in-situ soil flushing) and DH2 (located beyond sheet piles placed to block the transport of leaked diesel). Total petroleum hydrocarbon (TPH) concentrations and biogeochemical properties were monitored both in soil and groundwater for six months. A shift occurred in the groundwater type from Ca-HCO 3 to Na-Cl due to seawater intrusion during intense pumping, while the concentrations of Ni, Cu, Co, V, Cr, and Se increased substantially following surfactant (TWEEN 80) injection. The in-situ sampler with fine particles was more sensitive to variations in conditions during the remedial soil flushing process. In both wells, soil TPH concentrations in the <0.063-mm fraction were much higher than those in the <2-mm fraction. Increases in soil TPH in DH1 were consistent with the expected outcomes following well pumping and surfactant injection used to enhance TPH extraction. However, the number of diesel-degrading microorganisms decreased after surfactant injection. 16S-rRNA gene-based analysis also showed that the community composition and diversity depended on both particle size and diesel contamination. The multidisciplinary approach to the contaminated site assessments showed that soil flushing with surfactant enhanced diesel extraction, but negatively impacted in-situ diesel biodegradation as well as groundwater quality. The results also suggest that the in-situ sampler can be an effective monitoring tool for subsurface biogeochemistry as well as contaminant dynamics. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Simplified method for detecting tritium contamination in plants and soil

    USGS Publications Warehouse

    Andraski, Brian J.; Sandstrom, M.W.; Michel, R.L.; Radyk, J.C.; Stonestrom, David A.; Johnson, M.J.; Mayers, C.J.

    2003-01-01

    Cost-effective methods are needed to identify the presence and distribution of tritium near radioactive waste disposal and other contaminated sites. The objectives of this study were to (i) develop a simplified sample preparation method for determining tritium contamination in plants and (ii) determine if plant data could be used as an indicator of soil contamination. The method entailed collection and solar distillation of plant water from foliage, followed by filtration and adsorption of scintillation-interfering constituents on a graphite-based solid phase extraction (SPE) column. The method was evaluated using samples of creosote bush [Larrea tridentata (Sessé & Moc. ex DC.) Coville], an evergreen shrub, near a radioactive disposal area in the Mojave Desert. Laboratory tests showed that a 2-g SPE column was necessary and sufficient for accurate determination of known tritium concentrations in plant water. Comparisons of tritium concentrations in plant water determined with the solar distillation–SPE method and the standard (and more laborious) toluene-extraction method showed no significant difference between methods. Tritium concentrations in plant water and in water vapor of root-zone soil also showed no significant difference between methods. Thus, the solar distillation–SPE method provides a simple and cost-effective way to identify plant and soil contamination. The method is of sufficient accuracy to facilitate collection of plume-scale data and optimize placement of more sophisticated (and costly) monitoring equipment at contaminated sites. Although work to date has focused on one desert plant, the approach may be transferable to other species and environments after site-specific experiments.

  1. Effects of remediation train sequence on decontamination of heavy metal-contaminated soil containing mercury.

    PubMed

    Hseu, Zeng-Yei; Huang, Yu-Tuan; Hsi, Hsing-Cheng

    2014-09-01

    When a contaminated site contains pollutants including both nonvolatile metals and Hg, one single remediation technology may not satisfactorily remove all contaminants. Therefore, in this study, chemical extraction and thermal treatment were combined as a remediation train to remove heavy metals, including Hg, from contaminated soil. A 0.2 M solution of ethylenediamine tetraacetic acid (EDTA) was shown to be the most effective reagent for extraction of considerable amounts of Cu, Pb, and Zn (> 50%). Hg removal was ineffective using 0.2 M EDTA, but thermogravimetric analysis suggested that heating to 550 degrees C with a heating rate of 5 degrees C/min for a duration of 1 hr appeared to be an effective approach for Hg removal. With the employment of thermal treatment, up to 99% of Hg could be removed. However executing thermal treatment prior to chemical extraction reduced the effectiveness of the subsequent EDTA extraction because nonvolatile heavy metals were immobilized in soil aggregates after the 550 degrees C treatment. The remediation train of chemical extraction followed by thermal treatment appears to remediate soils that have been contaminated by many nonvolatile heavy metals and Hg. Implications: A remediation train conjoining two or more techniques has been initialized to remove multiple metals. Better understandings of the impacts of treatment sequences, namely, which technique should be employed first on the soil properties and the decontamination efficiency, are in high demand. This study provides a strategy to remove multiple heavy metals including Hg from a contaminated soil. The interactions between thermal treatment and chemical extraction on repartitioning of heavy metals was revealed. The obtained results could offer an integrating strategy to remediate the soil contaminated with both heavy metals and volatile contaminants.

  2. [Immobilization remediation of Cd and Pb contaminated soil: remediation potential and soil environmental quality].

    PubMed

    Sun, Yue-Bing; Wang, Peng-Chao; Xu, Ying-Ming; Sun, Yang; Qin, Xu; Zhao, Li-Jie; Wang, Lin; Liang, Xue-Feng

    2014-12-01

    A pot experiment was conducted to investigate the immobilization remediation effects of sepiolite on soils artificially combined contamination by Cd and Pb using a set of various pH and speciation of Cd and Pb in soil, heavy metal concentration in Oryza sativa L., and soil enzyme activity and microbial quantity. Results showed that the addition of sepiolite increased the soil pH, and the exchangeable fraction of heavy metals was converted into Fe-Mn oxide, organic and residual forms, the concentration of exchangeable form of Cd and Pb reduced by 1.4% - 72.9% and 11.8% - 51.4%, respectively, when compared with the control. The contents of heavy metals decreased with increasing sepiolite, with the maximal Cd reduction of 39.8%, 36.4%, 55.2% and 32.4%, respectively, and 22.1%, 54.6%, 43.5% and 17.8% for Pb, respectively, in the stems, leaves, brown rice and husk in contrast to CK. The addition of sepiolite could improve the soil environmental quality, the catalase and urease activities and the amount of bacteria and actinomycete were increased to some extents. Although the fungi number and invertase activity were inhibited compared with the control group, it was not significantly different (P > 0.05). The significant correlation between pH, available heavy metal content, urease and invertase activities and heavy metal concentration in the plants indicated that these parameters could be used to evaluate the effectiveness of stabilization remediation of heavy metal contaminated soil.

  3. Use of Maize (Zea mays L.) for phytomanagement of Cd-contaminated soils: a critical review.

    PubMed

    Rizwan, Muhammad; Ali, Shafaqat; Qayyum, Muhammad Farooq; Ok, Yong Sik; Zia-Ur-Rehman, Muhammad; Abbas, Zaheer; Hannan, Fakhir

    2017-04-01

    Maize (Zea mays L.) has been widely adopted for phytomanagement of cadmium (Cd)-contaminated soils due to its high biomass production and Cd accumulation capacity. This paper reviewed the toxic effects of Cd and its management by maize plants. Maize could tolerate a certain level of Cd in soil while higher Cd stress can decrease seed germination, mineral nutrition, photosynthesis and growth/yields. Toxicity response of maize to Cd varies with cultivar/varieties, growth medium and stress duration/extent. Exogenous application of organic and inorganic amendments has been used for enhancing Cd tolerance of maize. The selection of Cd-tolerant maize cultivar, crop rotation, soil type, and exogenous application of microbes is a representative agronomic practice to enhance Cd tolerance in maize. Proper selection of cultivar and agronomic practices combined with amendments might be successful for the remediation of Cd-contaminated soils with maize. However, there might be the risk of food chain contamination by maize grains obtained from the Cd-contaminated soils. Thus, maize cultivation could be an option for the management of low- and medium-grade Cd-contaminated soils if grain yield is required. On the other hand, maize can be grown on Cd-polluted soils only if biomass is required for energy production purposes. Long-term field trials are required, including risks and benefit analysis for various management strategies aiming Cd phytomanagement with maize.

  4. Ecosystem effects and the management of petroleum-contaminated soils on subantarctic islands.

    PubMed

    Errington, Ingrid; King, Catherine K; Wilkins, Daniel; Spedding, Tim; Hose, Grant C

    2018-03-01

    Human activity in the Polar Regions has resulted in petroleum contamination of soils. In this context, subantarctic islands are a unique management challenge for climatic, biological and logistical reasons. In this review we identify the main abiotic factors affecting petroleum-contaminated soils in the subantarctic environment, the primary effects of such contamination on biota, and lessons learned with regards to remediation techniques in this region. The sensitivity of biota to contamination depends on organism life stage, on soil properties, and on the degree of contaminant weathering. Initial studies using species endemic to subantarctic islands suggest that for fresh diesel fuel, sensitivities may range between 103 and 20 000 mg total petroleum hydrocarbons (TPH) kg -1 soil. Diesel that has undergone a short period of weathering is generally more toxic, with sensitivities ranging between 52 and 13 000 mg TPH kg -1 soil for an earthworm and a grass respectively (based on EC 20 and IC 50 values). A sufficient body of data from which to develop remediation targets for existing spills in the region does not yet exist for the region, but there has been a recent increase in research attention to address this data gap. A range of remediation methods have also now been trialled, and techniques such as in-ground aeration and nutrient addition have achieved some success. Passive management techniques such as permeable reactive barriers and phytoremediation are in preliminary stages of investigation for the region and show promise, not least because they cause less collateral disturbance than other methods. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  5. Effect of surfactant amendment to PAHs-contaminated soil for phytoremediation by maize (Zea mays L.).

    PubMed

    Liao, Changjun; Liang, Xujun; Lu, Guining; Thai, Truonggiang; Xu, Wending; Dang, Zhi

    2015-02-01

    Understanding the uptake of organic pollutants by plants is an important part of the assessment of risks from crops grown on contaminated soils. This study was an investigation of the effects of surfactants added to PAHs-contaminated soil on the uptake and accumulation of PAHs in maize tissues during phytoremediation. The accumulation of phenanthrene (PHE) and pyrene (PYR) by maize plant was not influenced significantly by the surfactant amendment to the soil. The distribution of PHE and PYR in maize tissues was not positively correlated with the corresponding lipid contents. Remarkably, the concentrations of PHE (20.9 ng g(-1)) and PYR (0.9 ng g(-1)) in maize grain were similar to or even much lower than those in some foods. Moreover, surfactants could enhance the removal of pollutants from contaminated soil during phytoremediation, which might be due to surfactant desorption ability and microbial activity in soil. The study suggests that use of maize plant with surfactant is an alternative technology for remediation of PAHs-contaminated soils. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Assessing soil and groundwater contamination from biofuel spills.

    PubMed

    Chen, Colin S; Shu, Youn-Yuen; Wu, Suh-Huey; Tien, Chien-Jung

    2015-03-01

    Future modifications of fuels should include evaluation of the proposed constituents for their potential to damage environmental resources such as the subsurface environment. Batch and column experiments were designed to simulate biofuel spills in the subsurface environment and to evaluate the sorption and desorption behavior of target fuel constituents (i.e., monoaromatic and polyaromatic hydrocarbons) in soil. The extent and reversibility of the sorption of aromatic biofuel constituents onto soil were determined. When the ethanol content in ethanol-blended gasoline exceeded 25%, enhanced desorption of the aromatic constituents to water was observed. However, when biodiesel was added to diesel fuel, the sorption of target compounds was not affected. In addition, when the organic carbon content of the soil was higher, the desorption of target compounds into water was lower. The empirical relationships between the organic-carbon normalized sorption coefficient (Koc) and water solubility and between Koc and the octanol-water partition coefficient (Kow) were established. Column experiments were carried out for the comparison of column effluent concentration/mass from biofuel-contaminated soil. The dissolution of target components depended on chemical properties such as the hydrophobicity and total mass of biofuel. This study provides a basis for predicting the fate and transport of hydrophobic organic compounds in the event of a biofuel spill. The spill scenarios generated can assist in the assessment of biofuel-contaminated sites.

  7. Bioavailability of barium to plants and invertebrates in soils contaminated by barite.

    PubMed

    Lamb, Dane T; Matanitobua, Vitukawalu P; Palanisami, Thavamani; Megharaj, Mallavarapu; Naidu, Ravi

    2013-05-07

    Barium (Ba) is a nonessential element to terrestrial organisms and is known to be toxic at elevated concentrations. In this study, the bioavailability and toxicity of Ba in barite (BaSO4) contaminated soils was studied using standard test organisms (Lactuca sativa L. "Great Lakes", Eisenia fetida). Contamination resulted from barite mining activities. Barium concentrations in contaminated soils determined by X-ray fluorescence were in the range 0.13-29.2%. Barite contaminated soils were shown to negatively impact both E. fetida and L. sativa relative to control soil. For E. fetida, pore-water concentrations and acid extractable Ba were linearly related to % body weight loss. In L. sativa, pore-water Ba and exchangeable Ba were both strongly related to shoot Ba and shoot biomass production. A negative linear relationship was observed between shoot Ba content and shoot weight (P < 0.0004, R(2) = 0.39), indicating that Ba accumulation is likely to have induced phytotoxicity. Plant weights were correlated to % weight loss in earthworm (r = -0.568, P = 0.028). Barium concentrations in pore-water were lower than predicted from barite solubility estimates but strongly related to exchangeable Ba, indicating an influence of ion exchange on Ba solubility and toxicity to E. fetida and L. sativa.

  8. Bacterial community and arsenic functional genes diversity in arsenic contaminated soils from different geographic locations

    PubMed Central

    Gu, Yunfu; D. Van Nostrand, Joy; Wu, Liyou; He, Zhili; Qin, Yujia; Zhao, Fang-Jie; Zhou, Jizhong

    2017-01-01

    To understand how soil microbial communities and arsenic (As) functional genes respond to soil arsenic (As) contamination, five soils contaminated with As at different levels were collected from diverse geographic locations, incubated for 54 days under flooded conditions, and examined by both MiSeq sequencing of 16S rRNA gene amplicons and functional gene microarray (GeoChip 4.0). The results showed that both bacterial community structure and As functional gene structure differed among geographical locations. The diversity of As functional genes correlated positively with the diversity of 16S rRNA genes (P< 0.05). Higher diversities of As functional genes and 16S rRNA genes were observed in the soils with higher available As. Soil pH, phosphate-extractable As, and amorphous Fe content were the most important factors in shaping the bacterial community structure and As transformation functional genes. Geographic location was also important in controlling both the bacterial community and As transformation functional potential. These findings provide insights into the variation of As transformation functional genes in soils contaminated with different levels of As at different geographic locations, and the impact of environmental As contamination on the soil bacterial community. PMID:28475654

  9. Survival, growth, detoxifying and antioxidative responses of earthworms (Eisenia fetida) exposed to soils with industrial DDT contamination.

    PubMed

    Shi, Yajuan; Zhang, Qiangbin; Huang, Dunqi; Zheng, Xiaoqi; Shi, Yajing

    2016-03-01

    The survival, growth, activity of the biotransformation system phase II enzyme glutathione-S-transferase (GST) and the oxidative defense enzyme catalase (CAT) of earthworms exposed to the contaminated soils from a former DDT plant and reference soils were investigated, and compared with the corresponding indicators in simulated soil-earthworm system, unpolluted natural soils with spiked-in DDT series, to identify the toxic effects of DDT on earthworms and their cellular defense system in complex soil system. The results indicated that DDT level in the contaminated soils was significantly higher than that in the reference soils with similar level of other pollutants and soil characters. The mortality, growth inhibition rates, GST and CST activities of earthworms exposed to the contaminated soils were significantly higher than that in reference soils. The contribution of historical DDT in contaminated soils to earthworms was confirmed by the DDT spiked tests. DDT spiked in soils at rates of higher than 200 mg·kg(-1) was significantly toxic to both the survival and the growth of earthworms. DDT significantly stimulated GST and CAT activity in earthworms after 14 days. The CAT and GST activities were also stimulated by DDT exposure at rates of 100 mg·kg(-1) after chronic exposure (42 days). The results provide implications for validating the extrapolation from laboratory simulated soils criteria to contaminated soils and for making site risk assessments. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Performance study and influence of radiation emission energy and soil contamination level on γ-radiation shielding of stabilised/solidified radionuclide-polluted soils.

    PubMed

    Falciglia, Pietro P; Puccio, Valentina; Romano, Stefano; Vagliasindi, Federico G A

    2015-05-01

    This work focuses on the stabilisation/solidification (S/S) of radionuclide-polluted soils at different (232)Th levels using Portland cement alone and with barite aggregates. The potential of S/S was assessed applying a full testing protocol and calculating γ-radiation shielding (γRS) index, that included the measurement of soil radioactivity before and after the S/S as a function of the emission energy and soil contamination level. The results indicate that setting processes are strongly dependent on the contaminant concentration, and for contamination level higher than 5%, setting time values longer than 72 h. The addition of barite aggregates to the cement gout leads to a slight improvement of the S/S performance in terms of durability and contaminant leaching but reduces the mechanical resistance of the treated soils samples. Barite addition also causes an increase in the γ-rays shielding properties of the S/S treatment up to about 20%. Gamma-ray measurements show that γRS strongly depends on the energy, and that the radioactivity with the contamination level was governed by a linear trend, while, γRS index does not depend on the radionuclide concentration. Results allow the calculated γRS values and those available from other experiments to be applied to hazard radioactive soil contaminations. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Phytoextraction of Cd-Contaminated Soils: Current Status and Future Challenges.

    PubMed

    Li, Jin-Tian; Baker, Alan J M; Ye, Zhi-Hong; Wang, Hong-Bin; Shu, Wen-Sheng

    2012-10-01

    Cadmium (Cd) is one of the most toxic and widely distributed pollutants in the environment. Cadmium contamination of soils has posed a serious threat to safe food production in many parts of the world. The authors present a comprehensive review of present status of phytoextraction technology for cleaning up Cd-contaminated soils, based primarily on the data resulting from both laboratory and field-scale studies that have been conducted to assess or improve the Cd phytoextraction potential of various plant species in the past decade. The encouraging results of field-scale studies have provided a fundamental basis to usher phytoextraction technology into practical use to remediate slightly to moderately Cd-contaminated soils in Europe and Asia, although this technology is not yet ready for widespread application. Chelators and microorganisms tested so far seem not to contribute to the applicability of Cd phytoextraction. The major challenges for the large-scale application of Cd phytoextraction are (a) how to further improve the efficiency of Cd phytoextraction, (b) how to cut the overall costs of Cd phytoextraction, and (c) how to get greater stakeholders' acceptance of Cd phytoextraction as a reliable option.

  12. Phytoextraction of Cd-Contaminated Soils: Current Status and Future Challenges

    PubMed Central

    Li, Jin-Tian; Baker, Alan J. M.; Ye, Zhi-Hong; Wang, Hong-Bin; Shu, Wen-Sheng

    2012-01-01

    Cadmium (Cd) is one of the most toxic and widely distributed pollutants in the environment. Cadmium contamination of soils has posed a serious threat to safe food production in many parts of the world. The authors present a comprehensive review of present status of phytoextraction technology for cleaning up Cd-contaminated soils, based primarily on the data resulting from both laboratory and field-scale studies that have been conducted to assess or improve the Cd phytoextraction potential of various plant species in the past decade. The encouraging results of field-scale studies have provided a fundamental basis to usher phytoextraction technology into practical use to remediate slightly to moderately Cd-contaminated soils in Europe and Asia, although this technology is not yet ready for widespread application. Chelators and microorganisms tested so far seem not to contribute to the applicability of Cd phytoextraction. The major challenges for the large-scale application of Cd phytoextraction are (a) how to further improve the efficiency of Cd phytoextraction, (b) how to cut the overall costs of Cd phytoextraction, and (c) how to get greater stakeholders’ acceptance of Cd phytoextraction as a reliable option. PMID:23335842

  13. LINKING WATERFOWL WITH CONTAMINANT SPECIATION IN RIPARIAN SOILS

    EPA Science Inventory

    This report summarizes the results of Mine Waste Technology Program (MWTP) Activity III, Project 38, Linking Waterfowl with Contaminant Speciation in Riparian Soils, implemented and funded by the U.S. Environmental Protection Agency (EPA) and jointly administered by EPA and the U...

  14. PHYTOREMEDIATION: USING PLANTS TO CLEAN UP CONTAMINATED SOIL, GROUNDWATER, AND WASTEWATER

    EPA Science Inventory

    Phytoremediation is an emerging cleanup technology for contaminated soils, groundwater, and wastewater that is both low-tech and low-cost. The cleanup technology is defined as the use of green plants to remove, contain, or render harmless such environmental contaminants as heavy ...

  15. EDTA-assisted leaching of Pb and Cd from contaminated soil.

    PubMed

    Qiao, Jiangbo; Sun, Huimin; Luo, Xiuhua; Zhang, Wang; Mathews, Shiny; Yin, Xianqiang

    2017-01-01

    Lead (Pb) and cadmium (Cd) contamination of soil and its harmful effects on human and environmental health have been one concern. In this study, batch and column leaching experiments were conducted to investigate the effects of two EDTA-assisted leaching methods, continuous and intermittent (dry-wet alternate), on the removal of Pb and Cd from contaminated soil. Total content and fractions of Pb and Cd at every 1 cm soil column depth were analyzed before and after the leaching. The results indicated that continuous leaching removed 75.43% of Pb (19.370 mg) and 53.21% of Cd (6.168 mg) and intermittent leaching removed 78.08% of Pb (20.051 mg) and 57.37% of Cd (6.650 mg), which showed intermittent leaching removed more Pb and Cd, but didn't differ significantly (P > 0.05) compared to the continuous leaching. In both leaching methods, total Pb and Cd content in all soil depths reduced after leaching. The two leaching methods made no significant differences in Pb and Cd distributions at different depths of the soil column. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Phosphate Treatment of Lead-Contaminated Soil: Effects on ...

    EPA Pesticide Factsheets

    Water quality threats associated with using phosphate-based amendments to remediate Pb-contaminated soils are a concern, particularly in riparian areas. This study investigated the effects of P application rates to a Pb-contaminated alluvial soil on Pb and P loss via surface water runoff, Pb accumulation in tall fescue (Festuca arundinacea Schreb; Kentucky 31), and Pb speciation. An alluvial soil was treated with triple superphosphate at P to Pb molar ratios of 0:1(control), 4:1, 8:1, and 16:1. After a 6- mo reaction period, rainfall simulation (RFS) studies were conducted, followed by tall fescue establishment and a second set of RFS studies (1 yr after treatment). Results from the first RFS (unvegetated) demonstrated that the total Pb and P concentrations in the effluents of 8:1 and 16:1 (P:Pb molar ratio) treatment levels were significantly greater (p 55%. X-ray absorption near-edge structure spectroscopy data showed that pyromorphite [Pb5(PO4)3OH,Cl,F] abundance ranged from 0% (control) to 32% (16:1 P:Pb; 1 yr after treatment) of the total soil Pb. Although P treatment stimulated pyromorphite formation, pyromorphite abundance was comparable between the P-treated soils. These findings suggest that a 4:1 (P:Pb molar ratio) P treatment may be a sufficient means of reducing Pb bioavailability while minimizing concerns related to P loss in an alluvial setting. The purpose of the current research was to examine the feasability of using phosphate based ammend

  17. Phytoremediation of mercury-contaminated soils by Jatropha curcas.

    PubMed

    Marrugo-Negrete, José; Durango-Hernández, José; Pinedo-Hernández, José; Olivero-Verbel, Jesús; Díez, Sergi

    2015-05-01

    Jatropha curcas plants species were tested to evaluate their phytoremediation capacity in soils contaminated by different levels of mercury. The experimental treatments consisted of four levels of mercury concentrations in the soil - T0, T1, T5, and T10 (0, 1, 5, and 10 μg Hg per g soil, respectively). The total mercury content absorbed by the different plant tissues (roots, stems and leaves) was determined during four months of exposure. The growth behavior, mercury accumulation, translocation (TF) and bioconcentration (BCF) factors were determined. The different tissues in J. curcas can be classified in order of decreasing accumulation Hg as follows: roots>leaves>stems. The highest cumulative absorption of the metal occurred between the second and third month of exposure. Maximum TF was detected during the second month and ranged from 0.79 to 1.04 for the different mercury concentrations. Values of BCF ranged from 0.21 to 1.43. Soils with T1 showed significantly higher BCF (1.43) followed by T10 (1.32) and T5 (0.91), all of them at the fourth month. On the other hand TFs were low (range 0.10-0.26) at the en of the experiment. The maximum reduction of biomass (16.3%) occurred for T10 (10 μg Hg g(-1)). In sum, J. curcas species showed high BCFs and low TFs, and their use could be a promising approach to remediating mercury-contaminated soils. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. A quick rhizobacterial selection tests for the remediation of copper contaminated soils.

    PubMed

    Braud, A M; Hubert, M; Gaudin, P; Lebeau, T

    2015-08-01

    The main objective of the study is to develop and improve quick bacterial tests to select the best candidates for the bioaugmentation of metal-contaminated soil, coupled with phytoextraction. Bacteria isolates (181) were selected from a collection originated from a Cu-contaminated sediment, on the basis of several miniaturized biochemical tests adapted to the copper contamination. Amongst them, we used a growth soil based-medium to select metal-tolerant bacteria, and their ability to grow and mobilize metals by mean of metabolites (siderophores, organic acids) was also assessed. The result of the bacterial selection tests showed differences in presence or absence of copper, especially for phosphate-solubilizing strains which ability decreased by 53% in the presence of copper hydroxide phosphate as compared to the standard tricalcium phosphate test. A promising Pseudomonas putida was selected from the collection. The study underlined the importance of choosing significant selection tests regarding the nature of the metal occurring in the soil to be cleaned-up to assess the real potential of each bacterial strain for subsequent soil bioaugmentation purposes. © 2015 The Society for Applied Microbiology.

  19. Immobilization of Cd in landfill-leachate-contaminated soil with cow manure compost as soil conditioners: A laboratory study.

    PubMed

    Liao, Zhuwei; Wang, Jia; Wan, Rui; Xi, Shuang; Chen, Zhuqi; Chen, Zhulei; Yu, Yingjian; Long, Sijie; Wang, Huabin

    2016-12-01

    Introducing cow manure compost as an amendment in landfill-leachate-contaminated soils is proved to be an effective technique for the immobilization of Cd in this study. Landfill-leachate-contaminated soil was collected from an unlined landfill in China and amended with a different blending quantity of cow manure compost (0, 12, 24, 36, and 48 g per 200 g soil), which was made by mixing cow manure and chaff at a ratio of 1/1 and maturing for 6 months. pH values of five different blending quantity mixtures increased by 0.2-0.4, and the organic matter levels increased by 2.5-7%, during a remediation period of 5 weeks. Four fractions of Cd named exchangeable Cd, reducible Cd, oxidizable Cd, and residual Cd in soil were respectively analyzed by a sequential extraction procedure. Introducing the cow manure compost application resulted in more than 40% lower exchangeable Cd but a higher concentration of oxidizable Cd in soils, and mass balance results showed nearly no Cd absorption by applied material, indicating that transformation of exchangeable Cd into oxidization forms was the main mechanism of Cd immobilization when cow manure compost was used as an amendment. The Pearson correlation showed that increasing of pH values significantly improved the efficiency of Cd immobilization, with a correlation coefficiency of 0.940 (p < 0.05). This is the first attempt at heavy metal immobilization in landfill-leachate-contaminated soil by cow manure compost, and findings of this work can be integrated to guide the application. Addition of cow manure compost (CMC) was effective in reducing exchangeable Cd in landfill-leachate-contaminated soils (LLCS). The immobilization effect of Cd was mainly assigned to the redistribution of labile soil Cd. Organic matter (OM) and pH value increased with CMC application. The pH values were more sensitive to Cd immobilization efficiency. It was proved that CMC can be safely and effectively used for the restoration of LLCS.

  20. Dissipation of the herbicide oxyfluorfen in subtropical soils and its potential to contaminate groundwater.

    PubMed

    Yen, Jui-Hung; Sheu, Wey-Shin; Wang, Yei-Shung

    2003-02-01

    The dissipation and mobility of the herbicide oxyfluorfen (2-chloro-alpha,alpha,alpha-trifluoro-p-tolyl 3-ethoxy-4-nitrophenyl ether) in field soil of Taiwan were investigated in the laboratory with six tea garden soils. The dissipation coefficients of oxyfluorfen in soils of different moisture content (30%, 60%, and 90% of soil field capacity) and soil temperature (10 degrees C, 25 degrees C, and 40 degrees C) were studied. Results indicate that the half-life of oxyfluorfen ranged from 72 to 160 days for six tea garden soils. It was found that if the temperature is high, the dissipation rate is rapid, and there is almost no dissipation at 10 degrees C. Possible contamination of groundwater by the herbicide oxyfluorfen was assessed using the behavior assessment model and the groundwater pollution-potential (GWP) model. The results obtained after evaluating the residue and travel time using the GWP model illustrated that oxyfluorfen is not very mobile in soil and may not contaminate groundwater under normal conditions. But in the case of soil of extremely low organic carbon content and coarse texture, oxyfluorfen has the potential to contaminate groundwater less than 3m deep.

  1. Biosurfactant-assisted phytoremediation of multi-contaminated industrial soil using sunflower (Helianthus annuus L.).

    PubMed

    Liduino, Vitor S; Servulo, Eliana F C; Oliveira, Fernando J S

    2018-06-07

    This study evaluated the use of commercial rhamnolipid biosurfactant supplementation in the phytoremediation of a soil via sunflower (Helianthus annuus L.) cultivation. The soil, obtained from an industrial area, was co-contaminated with heavy metals and petroleum hydrocarbons. The remediation tests were monitored for 90 days. The best results for removal of contaminants were obtained from the tests in which the sunflower plants were cultivated in soil with 4 mg kg -1 of the rhamnolipid. Under these conditions, reductions of 58% and 48% were obtained in the total petroleum hydrocarbon (TPH) and polycyclic aromatic hydrocarbon (PAH) concentrations, respectively; reductions in the concentrations of the following metals were also achieved: Ni (41%), Cr (30%), Pb (29%), and Zn (20%). The PCR-DGGE analysis of soil samples collected before and after the treatments verified that the plant cultivation and biosurfactants supplementation had little effect on the structure of the dominant bacterial community in the soil. The results indicated that sunflower cultivation with the addition of a biosurfactant is a viable and efficient technology to treat soils co-contaminated with heavy metals and petroleum hydrocarbons.

  2. A survey of lead contamination in soil along Interstate 880, Alameda County, California.

    PubMed

    Teichman, J; Coltrin, D; Prouty, K; Bir, W A

    1993-09-01

    This study was undertaken to determine the levels of lead in soils taken from yards of homes in close proximity to a major freeway. Soils were collected from the yards of homes in communities adjacent to the freeway and within a 1-mile radius. Samples were analyzed using U.S. Environmental Protection Agency (EPA) methods and atomic absorption instrumentation. Ten percent of the samples were split and sent to a second laboratory for quality control. The possibility of lead-based paint contributing to the contamination was eliminated by sampling more than 20 feet from the homes. The soils closest to the highway showed lead levels exceeding California's and EPA's criteria for hazardous waste. A stratified sample of the depth of contamination in soils was also undertaken. Previously identified "hot spots" (soils with lead levels exceeding 500 ppm in the top 0.75 inch) were core sampled. Results indicated 90% of the subsurface samples contained lead exceeding the surface contaminations. This may be attributed to decades of urban lead-laden dust deposition. As the use of leaded gasolines have diminished in the past decade, the uppermost layers of soil/dust contained lower amounts of lead.

  3. A combined process coupling phytoremediation and in situ flushing for removal of arsenic in contaminated soil.

    PubMed

    Yan, Xiulan; Liu, Qiuxin; Wang, Jianyi; Liao, Xiaoyong

    2017-07-01

    Phytoremediation and soil washing are both potentially useful for remediating arsenic (As)-contaminated soils. We evaluated the effectiveness of a combined process coupling phytoremediation and in situ soil flushing for removal of As in contaminated soil through a pilot study. The results showed that growing Pteris vittata L. (P.v.) accompanied by soil flushing of phosphate (P.v./Flushing treatment) could significantly decrease the total As concentration of soil over a 37day flushing period compared with the single flushing (Flushing treatment). The P.v./Flushing treatment removed 54.04% of soil As from contaminated soil compared to 47.16% in Flushing treatment, suggesting that the growth of P. vittata was beneficial for promoting the removal efficiency. We analyzed the As fractionation in soil and As concentration in soil solution to reveal the mechanism behind this combined process. Results showed that comparing with the control treatment, the percent of labile arsenate fraction significantly increased by 17% under P.v./Flushing treatment. As concentration in soil solution remained a high lever during the middle and later periods (51.26-56.22mg/L), which was significantly higher than the Flushing treatment. Although soil flushing of phosphate for more than a month, P. vittata still had good accumulation and transfer capacity of As of the soil. The results of the research revealed that combination of phytoremediation and in situ soil flushing is available to remediate As-contaminated soils. Copyright © 2016. Published by Elsevier B.V.

  4. Role of organic amendments on enhanced bioremediation of heavy metal(loid) contaminated soils.

    PubMed

    Park, Jin Hee; Lamb, Dane; Paneerselvam, Periyasamy; Choppala, Girish; Bolan, Nanthi; Chung, Jae-Woo

    2011-01-30

    As land application becomes one of the important waste utilization and disposal practices, soil is increasingly being seen as a major source of metal(loid)s reaching food chain, mainly through plant uptake and animal transfer. With greater public awareness of the implications of contaminated soils on human and animal health there has been increasing interest in developing technologies to remediate contaminated sites. Bioremediation is a natural process which relies on soil microorganisms and higher plants to alter metal(loid) bioavailability and can be enhanced by addition of organic amendments to soils. Large quantities of organic amendments, such as manure compost, biosolid and municipal solid wastes are used as a source of nutrients and also as a conditioner to improve the physical properties and fertility of soils. These organic amendments that are low in metal(loid)s can be used as a sink for reducing the bioavailability of metal(loid)s in contaminated soils and sediments through their effect on the adsorption, complexation, reduction and volatilization of metal(loid)s. This review examines the mechanisms for the enhanced bioremediation of metal(loid)s by organic amendments and discusses the practical implications in relation to sequestration and bioavailability of metal(loid)s in soils. Copyright © 2010 Elsevier B.V. All rights reserved.

  5. Improving the phytoremediation of heavy metals contaminated soil by use of sewage sludge

    PubMed Central

    Placek, Agnieszka; Grobelak, Anna; Kacprzak, Malgorzata

    2016-01-01

    ABSTRACT Sewage sludge, in particular from the food industry, is characterized by fertilizing properties, due to the high content of organic matter and nutrients. The application of sewage sludge causes an improvement of soil parameters as well as increase in cation exchange capacity, and thus stronger binding of cations in the soil environment, which involves the immobilization of nutrients and greater resistance to contamination. In a field experiment sewage sludge has been used as an additive to the soil supporting the phytoremediation process of land contaminated with heavy metals (Cd, Zn, and Pb) using trees species: Scots pine (Pinus silvestris L.), Norway spruce (Picea abies L.), and oak (Quercus robur L.). The aim of the research was to determine how the application of sewage sludge into the soil surface improves the phytoremediation process. The conducted field experiment demonstrated that selected trees like Scots pine and Norway spruce, because of its excellent adaptability, can be used in the remediation of soil. Oak should not be used in the phytoremediation process of soils contaminated with high concentrations of trace elements in the soil, because a significant amount of heavy metals was accumulated in the leaves of oak causing a risk of recontamination. PMID:26368503

  6. Uptake of cesium-137 by crops from contaminated soils

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Demirel, H.; Oezer, I.; Celenk, I.

    1994-11-01

    The Turkish tea crop was contaminated following the Chernobyl nuclear accident. Finding ways to dispose of the contaminated tea (Camellia sinensis L.) without damaging the environment was the goal of this research conducted at the Turkish Atomic Energy Authority (TAEA). In this study, an investigation was made of {sup 137}Cs activities of the plants and the ratios of transfer of {sup 137}Cs activity to plants when the contaminated tea was applied to the soil. Experiments were conducted in the field and in pots under greenhouse conditions. The activities of the tea applied in the field ranged from 12 500 tomore » 72 800 Bq/m{sup 2}, whereas this activity was constant at 8000 Bq/pot in the greenhouse experiment. The transfer of {sup 137}Cs from soil to the plants was between 0.037 and 1.057% for wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), corn (Zea mays indentata Sturt), bean (Phaseolus vulgaris L.), lettuce (Lactuca sativa L.), and grass (Lolium perenne L.). The ratio of the transfer of {sup 137}Cs activity to plants increased as the activity {sup 137}Cs in tea applied to soil was increased. The activity in the plants increased due to increased uptake of {sup 137}Cs by plants. 12 refs., 2 figs., 2 tabs.« less

  7. FORCED AIR VENTILATION FOR REMEDIATION OF UNSATURATED SOILS CONTAMINATED BY VOC

    EPA Science Inventory

    Parameters which were expected to control the removal process of VOCs from contaminated soil during the SVE operation were studied by means of numerical simulations and laboratory experiments in this project. Experimental results of SVE with soil columns in the laboratory indicat...

  8. [Promotion effects of microorganisms on phytoremediation of heavy metals-contaminated soil].

    PubMed

    Yang, Zhuo; Wang, Zhan-Li; Li, Bo-Wen; Zhang, Rui-Fang

    2009-08-01

    Taking Brassica juncea as a hyperaccumulator, a pot experiment was conducted to study the effects of Bacillusme gaterium - Bacillus mucilaginosus mixed agent and Aspergillus niger 30177 fermentation liquor on the phytoremediation of Cd, Pb, and Zn-contaminated soil. The B. gaterium - B. mucilaginosus mixed agent not only promoted the growth of B. juncea, but also increased the soil Cd, Pb, and Zn uptake by the hyperaccumulator, with the phytoremediation efficiency enhanced greatly. The enrichment amount of Cd, Pb and Zn in B. juncea on the soil added with soluble Cd, Pb and Zn increased by 1.18, 1.54 and 0.85 folds, while that on the soil added with Cd, Pb and Zn-contaminated sediment increased by 4.00, 0. 64 and 0. 65 folds, respectively, compared with the control. A. niger 30177 fermentation liquor increased the soil Cd, Pb, and Zn uptake by B. juncea. Comparing with the control, the enrichment amount of Cd, Pb and Zn in aboveground part of B. juncea on the soil added with soluble Cd, Pb and Zn increased by 88.82%, 129.04% and 16.80%, while that on the soil added with Cd, Pb and Zn-contaminated sediment increased by 78.95%, 113.63% and 33.85%, respectively. However, A. niger 30177 fermentation liquor decreased the B. juncea biomass greatly, having less effect in the enhancement of phytoremediation efficiency. The analysis of reversed-phase high performance liquid chromatography showed that the fermentation liquor of B. gaterium and B. mucilaginosus contained some organic acids such as oxalic acid and citric acid. These acids could dissolve the heavy metals to some degree, and accordingly, enhance the bioavailability of the metals.

  9. Evaluation of PCDD/PCDF Biodegration Using Bacterial Isolates from Contaminated Soils

    USDA-ARS?s Scientific Manuscript database

    There is a need to identify bacteria that can degrade environmental contaminants and a potentially fruitful place to identify such bacteria is within contaminated soil. Dioxins from adjacent to railroad tracts were isolated by sonicating in acetone/toluene followed by alumina, tri-phase silica, and ...

  10. Comparison of germination and seed vigor of sunflower in two contaminated soils of different texture

    NASA Astrophysics Data System (ADS)

    Zhao, Xin; Han, Jaemaro; Lee, Jong Keun; Kim, Jae Young

    2014-05-01

    Phytoremediation as an emerging low-cost and ecologically friendly alternative to the conventional soil remediation technologies has gained a great deal of attention and into lots of research. As a kind of the methods that use of green plants to remediate heavy metals contaminated soils, the early growth status of plant seeds in the contaminated environmental directly affects the effect of phytoremediation. Germination test in the water (aqueous solution of heavy metal) is generally used for assessing heavy metal phytotoxicity and possibility of plant growth, but there is a limit. Because soil is commonly main target of phytoremediation, not the water. The bioavailability of heavy metals in the soil also depends on the texture. So soil texture is an important factor of phytoremediation effect. Sunflower is the representative species which have good tolerance to various heavy metals; furthermore, the seeds of sunflower can be used as the raw-material for producing bio-diesel. The objectives of this research were to investigate germination rate of sunflowers in various heavy metal contaminated soils and to compare the seedling vigor index (SVI) of sunflower in two contaminated soils of different texture. Sunflower (Helianthusannuus L.) seeds were obtained from a commercial market. In order to prove the soil texture effect on heavy metal contaminated soil, germination tests in soil were conducted with two different types of soil texture (i.e., loam soil and sandy loam soil) classified by soil textural triangle (defined by USDA) including representative soil texture of Korea. Germination tests in soil were conducted using KS I ISO 11260-1 (2005) for reference that sunflower seeds were incubated for 7 days in dark at 25 ± 1 Celsius degree. The target heavy metals are Nickel (Ni) and Zinc (Zn). The Ni and Zn concentrations were 0, 10, 50, 100, 200, 300, 500 mg-Ni/kg-dry soil, and 0, 10, 50, 100, 300, 500, 900 mg-Zn/kg-dry soil, respectively. After germination test for 7

  11. Is the soil quality monitoring an effective tool in consumers' protection of agricultural crops from cadmium soil contamination?-a case of the Silesia region (Poland).

    PubMed

    Piekut, Agata; Baranowska, Renata; Marchwińska-Wyrwał, Ewa; Ćwieląg-Drabek, Małgorzata; Hajok, Ilona; Dziubanek, Grzegorz; Grochowska-Niedworok, Elżbieta

    2017-12-16

    The monitoring of soil quality should be a control tool used to reduce the adverse health effects arising from exposure to toxic chemicals in soil through cultivated crop absorption. The aim of the study was to evaluate the effectiveness of the monitoring and control system of soil quality in Poland, in terms of consumer safety, for agricultural plants cultivated in areas with known serious cadmium contamination, such as Silesia Province. To achieve the objective, the contents of cadmium in soils and vegetables in the Silesia administrative area were examined. The obtained results were compared with the results of soil contamination from the quality monitoring of arable soil in Poland. The studies show a significant exceedance of the permissible values of cadmium in soil samples and the vegetables cultivated on that soil. The threat to consumer health is a valid concern, although this threat was not indicated by the results of the national monitoring of soil quality. The results indicated an unequal distribution of risk to consumers resulting from contaminated soil. Moreover, the monitoring systems should be designed at the local or regional scale to guarantee the safety of consumers of edible plants cultivated in the areas contaminated with cadmium.

  12. Sources and remediation techniques for mercury contaminated soil.

    PubMed

    Xu, Jingying; Bravo, Andrea Garcia; Lagerkvist, Anders; Bertilsson, Stefan; Sjöblom, Rolf; Kumpiene, Jurate

    2015-01-01

    Mercury (Hg) in soils has increased by a factor of 3 to 10 in recent times mainly due to combustion of fossil fuels combined with long-range atmospheric transport processes. Other sources as chlor-alkali plants, gold mining and cement production can also be significant, at least locally. This paper summarizes the natural and anthropogenic sources that have contributed to the increase of Hg concentration in soil and reviews major remediation techniques and their applications to control soil Hg contamination. The focus is on soil washing, stabilisation/solidification, thermal treatment and biological techniques; but also the factors that influence Hg mobilisation in soil and therefore are crucial for evaluating and optimizing remediation techniques are discussed. Further research on bioremediation is encouraged and future study should focus on the implementation of different remediation techniques under field conditions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Simple surface foam application enhances bioremediation of oil-contaminated soil in cold conditions.

    PubMed

    Jeong, Seung-Woo; Jeong, Jongshin; Kim, Jaisoo

    2015-04-09

    Landfarming of oil-contaminated soil is ineffective at low temperatures, because the number and activity of micro-organisms declines. This study presents a simple and versatile technique for bioremediation of diesel-contaminated soil, which involves spraying foam on the soil surface without additional works such as tilling, or supply of water and air. Surfactant foam containing psychrophilic oil-degrading microbes and nutrients was sprayed twice daily over diesel-contaminated soil at 6 °C. Removal efficiencies in total petroleum hydrocarbon (TPH) at 30 days were 46.3% for landfarming and 73.7% for foam-spraying. The first-order kinetic biodegradation rates for landfarming and foam-spraying were calculated as 0.019 d(-1) and 0.044 d(-1), respectively. Foam acted as an insulating medium, keeping the soil 2 °C warmer than ambient air. Sprayed foam was slowly converted to aqueous solution within 10-12h and infiltrated the soil, providing microbes, nutrients, water, and air for bioaugmentation. Furthermore, surfactant present in the aqueous solution accelerated the dissolution of oil from the soil, resulting in readily biodegradable aqueous form. Significant reductions in hydrocarbon concentration were simultaneously observed in both semi-volatile and non-volatile fractions. As the initial soil TPH concentration increased, the TPH removal rate of the foam-spraying method also increased. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Proposal of a sequential treatment methodology for the safe reuse of oil sludge-contaminated soil.

    PubMed

    Mater, L; Sperb, R M; Madureira, L A S; Rosin, A P; Correa, A X R; Radetski, C M

    2006-08-25

    In this study sequential steps were used to treat and immobilize oil constituents of an oil sludge-contaminated soil. Initially, the contaminated soil was oxidized by a Fenton type reaction (13 wt% for H(2)O(2); 10mM for Fe(2+)). The oxidative treatment period of 80 h was carried out under three different pH conditions: 20 h at pH 6.5, 20 h at pH 4.5, and 40 h at pH 3.0. The oxidized contaminated sample (3 kg) was stabilized and solidified for 2h with clay (1 kg) and lime (2 kg). Finally, this mixture was solidified by sand (2 kg) and Portland cement (4 kg). In order to evaluate the efficiency of different processes to treat and immobilize oil contaminants of the oil sludge-contaminated soil, leachability and solubility tests were performed and extracts were analyzed according to the current Brazilian waste regulations. Results showed that the Fenton oxidative process was partially efficient in degrading the oil contaminants in the soil, since residual concentrations were found for the PAH and BTEX compounds. Leachability tests showed that clay-lime stabilization/solidification followed by Portland cement stabilization/solidification was efficient in immobilizing the recalcitrant and hazardous constituents of the contaminated soil. These two steps stabilization/solidification processes are necessary to enhance environmental protection (minimal leachability) and to render final product economically profitable. The treated waste is safe enough to be used on environmental applications, like roadbeds blocks.

  15. Tracing contamination sources in soils with Cu and Zn isotopic ratios.

    PubMed

    Fekiacova, Z; Cornu, S; Pichat, S

    2015-06-01

    Copper (Cu) and zinc (Zn) are naturally present and ubiquitous in soils and are important micronutrients. Human activities contribute to the input of these metals to soils in different chemical forms, which can sometimes reach a toxic level for soil organisms and plants. Isotopic signatures could be used to trace sources of anthropogenic Cu and Zn pollution. The aim of this paper is to determine whether it is possible to identify (i) Cu and Zn contamination in soils and their sources, on the basis of their isotopic signatures, and (ii) situations that are a priori favorable or not for tracing Cu and Zn pollution using the isotopic approach. Therefore, we compiled data from the literature on Cu and Zn isotopes in soils, rocks and pollutants and added to this database the results of our own research. As only a few studies have dealt with agricultural contamination, we also studied a soil toposequence from Brittany, France, that experienced spreading of pig slurry for tens of years. In the surface horizons of the natural soils, the δ(65)Cu values vary from -0.15 to 0.44‰ and the δ(66)Zn from -0.03 to 0.43‰. Furthermore, vertical variations along soil profiles range from -0.95 to 0.44‰ for δ(65)Cu and from -0.53 to 0.64‰ for δ(66)Zn values. We concluded that pedogenetic processes can produce isotopic fractionation, yet, it is not always discernible and can be overprinted by an exogenous isotopic signature. Furthermore, some contaminants are enriched in heavy Cu or in light Zn compared to the rock or soil, but no generalization can be made. The anthropogenic inputs can be identified based on stable Cu and Zn isotope ratios if the isotope ratios of the sources are different from those of the soil, which needs to be tested for each individual case. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Heavy metal-immobilizing organoclay facilitates polycyclic aromatic hydrocarbon biodegradation in mixed-contaminated soil.

    PubMed

    Biswas, Bhabananda; Sarkar, Binoy; Mandal, Asit; Naidu, Ravi

    2015-11-15

    Soils contaminated with a mixture of heavy metals and polycyclic aromatic hydrocarbons (PAHs) pose toxic metal stress to native PAH-degrading microorganisms. Adsorbents such as clay and modified clay minerals can bind the metal and reduce its toxicity to microorganisms. However, in a mixed-contaminated soil, an adsorption process more specific to the metals without affecting the bioavailability of PAHs is desired for effective degradation. Furthermore, the adsorbent should enhance the viability of PAH-degrading microorganisms. A metal-immobilizing organoclay (Arquad(®) 2HT-75-bentonite treated with palmitic acid) (MIOC) able to reduce metal (cadmium (Cd)) toxicity and enhance PAH (phenanthrene) biodegradation was developed and characterized in this study. The MIOC differed considerably from the parent clay in terms of its ability to reduce metal toxicity (MIOC>unmodified bentonite>Arquad-bentonite). The MIOC variably increased the microbial count (10-43%) as well as activities (respiration 3-44%; enzymatic activities up to 68%), and simultaneously maintained phenanthrene in bioavailable form in a Cd-phenanthrene mixed-contaminated soil over a 21-day incubation period. This study may lead to a new MIOC-assisted bioremediation technique for PAHs in mixed-contaminated soils. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Bacterial community profile of contaminated soils in a typical antimony mining site.

    PubMed

    Wang, Ningning; Zhang, Suhuan; He, Mengchang

    2018-01-01

    The soils around the world's largest antimony mine have been contaminated by high concentrations of Sb and As, which might influence microbial diversity in the surrounding soils. The ecological effects of bioavailable Sb and As on the composition and diversity of microbial community in soils remain unknown. In this study, the relative abundance, taxonomic diversity and composition of bacterial community in soils from a typical Sb mine area, and the relationship between the bacterial community and bioavailable concentrations as well as environmental factors have been investigated comprehensively using high-throughput sequencing (HTS) and diffusive gradients in thin films (DGT). The results indicated that Proteobacteria, Acidobacteria, Chloroflexi, Bacteroidetes, Actinobacteria, Gemmatimonadetes, and Cyanobacteria were the dominant bacterial populations at phylum level in all soil samples, accounting for more than 80% of the bacteria sequenced. The abundance and diversity of bacterial community vary along a metal contamination gradient. Redundancy discriminate analysis (RDA) revealed that 74.74% of bacterial community variation in the contaminated soils was explained by six environmental factors (pH, Sb DGT , As DGT , potential ecological risk index (RI), TC, TN), among which pH, Sb DGT , and As DGT were dominant factors influencing the composition and diversity of bacteria. This study contributes to our understanding of microbial diversity in a local ecosystem and introduces the option of studying bioavailable Sb and As using DGT.

  18. Petroleum-degrading microbial numbers in rhizosphere and non-rhizosphere crude oil-contaminated soil.

    PubMed

    Kirkpatrick, W D; White, P M; Wolf, D C; Thoma, G J; Reynolds, C M

    2008-01-01

    Phytoremediation can be a cost-effective and environmentally acceptable method to clean up crude oil-contaminated soils in situ. Our research objective was to determine the effects of nitrogen (N) additions and plant growth on the number of total hydrocarbon (TH)-, alkane-, and polycyclic aromatic hydrocarbon (PAH)-degrading microorganisms in weathered crude oil-contaminated soil. A warm-season grass, sudangrass (Sorghum sudanense (Piper) Stapf), was grown for 7 wk in soil with a total petroleum hydrocarbon (TPH) level of 16.6 g TPH/kg soil. Nitrogen was added based upon TPH-C:added total N (TPH-C:TN) ratios ranging from 44:1 to 11:1. Unvegetated and unamended controls were also evaluated. The TH-, alkane-, and PAH-degrading microbial numbers per gram of dry soil were enumerated from rhizosphere and non-rhizosphere soil for vegetated pots and non-rhizosphere soil populations were enumerated from non-vegetated pots. Total petroleum-degrading microbial numbers were also calculated for each pot. The TH-, alkane-, and PAH-degrading microbial numbers per gram of dry soil in the sudangrass rhizosphere were 3.4, 2.6, and 4.8 times larger, respectively, than those in non-rhizosphere soil across all N rates. The presence of sudangrass resulted in significantly more TH-degrading microorganisms per pot when grown in soil with a TPH-C:TN ratio of 11:1 as compared to the control. Increased plant root growth in a crude oil-contaminated soil and a concomitant increase in petroleum-degrading microbial numbers in the rhizosphere have the potential to enhance phytoremediation.

  19. Spectral induced polarization (SIP) measurement of NAPL contaminated soils

    NASA Astrophysics Data System (ADS)

    Schwartz, N.; Huisman, J. A.; Furman, A.

    2010-12-01

    The potential applicability of spectral induce polarization (SIP) as a tool to map NAPLs (non aqueous phase liquids) contaminants at the subsurface lead researchers to investigate the electric signature of those contaminant on the spectral response. However, and despite the cumulative efforts, the effect of NAPL on the electrical properties of soil, and the mechanisms that control this effect are largely unknown. In this work a novel experiment is designed to further examine the effect of NAPL on the electrical properties of partially saturated soil. The measurement system that used is the ZEL-SIP04 impedance meter developed at the Forschungszentrum Julich, Germany. The system accurately (nominal phase precision of 0.1 mrad below 1 kHz) measures the phase and the amplitude of a material possessing a very low polarization (such as soil). The sample holder has a dimension of 60 cm long and 4.6 cm in diameter. Current and potential electrodes were made of brass, and while the current electrodes were inserted in full into the soil, the contact between the potential electrode and the soil was made through an Agarose bridge. Two types of soils were used: clean quartz sand, and a mixture of sand with clean Bentonite. Each soil (sandy or clayey) was mixed with water to get saturation degree of 30%. Following the mixture with water, NAPL was added and the composite were mixed again. Packing was done by adding and compressing small portions of the soil to the column. A triplicate of each mixture was made with a good reproducible bulk density. Both for the sandy and clayey soils, the results indicate that additions of NAPL decrease the real part of the complex resistivity. Additionally, for the sandy soil this process is time depended, and that a further decrease in resistivity develops over time. The results are analyzed considering geometrical factors: while the NAPL is electrically insulator, addition of NAPL to the soil is expected to increase the connectivity of the

  20. Phytoremediation of Petroleum Hydrocarbon (PHC) Contaminated Soil by Using Mimosa pudica L. .

    PubMed

    Budhadev, Basumatary; Rubul, Saikia; Sabitry, Bordoloi; Hari Prasad, Sarma

    2014-07-01

    The aim of this study was to evaluate the efficiency of Mimosa pudica L. that could be effective in phytoremediation of PHC-contaminated soil. Experiments were conducted in net house to determine the tolerance of this species to a heavy crude oil contaminated soil under the application of two fertilizer levels and reduction of PHC was monitored for 180 days. Assessment of plant growth, biomass and Total Oil and Grease (TOG) degradation were carried out at an interval of 60 days. In the presence of contaminants, biomass and plant height were reduced up to 27% and 10.4% respectively. Experiments with different percentages of crude oil showed that M. pudica could tolerate crude-oil contamination up to 6.2% (w/w). The estimation of TOG in soil of the tested plants revealed that M. pudica could decrease 31.7% of crude oil contaminants in low fertilizer level (200N, 100P, 100K) and 24.7% in high fertilizer level (240N, 120P, 120K). In case of unplanted pots, the reduction of TOG was 13.7% in low fertilizer level and 11.2% in high fertilizer level. This experiment has identified the suitability of a native candidate plant species for further investigation of their phytoremediation potential.

  1. Phytoremediation of arsenic contaminated soil by arsenic accumulators: a three year study.

    PubMed

    Raj, Anshita; Singh, Nandita

    2015-03-01

    To investigate whether phytoremediation can remove arsenic from the contaminated area, a study was conducted for three consecutive years to determine the efficiency of Pteris vittata, Adiantum capillus veneris, Christella dentata and Phragmites karka, on arsenic removal from the arsenic contaminated soil. Arsenic concentrations in the soil samples were analysed after harvesting in 2009, 2010 and 2011 at an interval of 6 months. Frond arsenic concentrations were also estimated in all the successive harvests. Fronds resulted in the greatest amount of arsenic removal. Root arsenic concentrations were analysed in the last harvest. Approximately 70 % of arsenic was removed by P. vittata which was recorded as the highest among the four plant species. However, 60 % of arsenic was removed by A. capillus veneris, 55.1 % by C. dentata and 56.1 % by P. karka of arsenic was removed from the contaminated soil in 3 years.

  2. Repeated phytoextraction of four metal-contaminated soils using the cadmium/zinc hyperaccumulator Sedum plumbizincicola.

    PubMed

    Li, Zhu; Wu, Longhua; Hu, Pengjie; Luo, Yongming; Zhang, Hao; Christie, Peter

    2014-06-01

    A cadmium/zinc hyperaccumulator extracted metals from four contaminated soils over three years in a glasshouse experiment. Changes in plant metal uptake and soil total (aqua regia-extractable) and available metals were investigated. Plant Cd concentrations in a high-Cd acid soil and plant Zn concentrations in two acid soils decreased during repeated phytoextraction and were predicted by soil available metal concentrations. However, on repeated phytoextraction, plant Cd concentrations remained constant in lightly Cd-polluted acid soils, as did plant Cd and Zn in alkaline soils, although soil available metal concentrations decreased markedly. After phytoextraction acid soils showed much higher total metal removal efficiencies, indicating possible suitability of phytoextraction for acid soils. However, DGT-testing, which takes soil metal re-supply into consideration, showed substantial removal of available metal and distinct decreases in metal supply capacity in alkaline soils after phytoextraction, suggesting that a strategy based on lowering the bioavailable contaminant might be feasible. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Phytoremediation of crude oil contaminated soil using nut grass, Cyperus rotundus.

    PubMed

    Basumatary, Budhadev; Saikia, Rubul; Bordoloi, Sabitry

    2012-09-01

    The aim of this study was to evaluate the efficacy of Cyperus rotundus (nut grass), that could be effective in phytoremediation of crude oil contaminated soil. A net house experiment was conducted with different concentrations (2.05, 4.08, 6.1, 8.15 and 10.2%) of crude oil-contaminated soil for 180 days. Plant growth, biomass, total oil and grease (TOG) degradation and microbial numbers were analyzed at different intervals i.e. 60,120 and 180 days in different percentages of crude oil contaminated soil. In presence of crude oil, plant biomass and heights reduced up to 26 and 21.9% respectively. Concerning TOG content in soil, C. rotundus could decrease up to 50.01, 46.1, 42.6, 38.8 and 32.6% in treatment I, II, III, IV and V respectively in vegetated pots during 180 days. In case of unvegetated pots, the reductions of TOG were 4.4, 5.6, 6.6, 7.6 and 9.6% in treatment A, B, C, D and E respectively. However, there was significant degradation (P = 0.05) of TOG in vegetated pots in comparison to unvegetated pots thereby proving the efficacy of this plant species for use in phytoremediation.

  4. Procedures for sampling radium-contaminated soils

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Fleischhauer, H.L.

    Two procedures for sampling the surface layer (0 to 15 centimeters) of radium-contaminated soil are recommended for use in remedial action projects. Both procedures adhere to the philosophy that soil samples should have constant geometry and constant volume in order to ensure uniformity. In the first procedure, a ''cookie cutter'' fashioned from pipe or steel plate, is driven to the desired depth by means of a slide hammer, and the sample extracted as a core or plug. The second procedure requires use of a template to outline the sampling area, from which the sample is obtained using a trowel ormore » spoon. Sampling to the desired depth must then be performed incrementally. Selection of one procedure over the other is governed primarily by soil conditions, the cookie cutter being effective in nongravelly soils, and the template procedure appropriate for use in both gravelly and nongravelly soils. In any event, a minimum sample volume of 1000 cubic centimeters is recommended. The step-by-step procedures are accompanied by a description of the minimum requirements for sample documentation. Transport of the soil samples from the field is then addressed in a discussion of the federal regulations for shipping radioactive materials. Interpretation of those regulations, particularly in light of their application to remedial action soil-sampling programs, is provided in the form of guidance and suggested procedures. Due to the complex nature of the regulations, however, there is no guarantee that our interpretations of them are complete or entirely accurate. Preparation of soil samples for radium-226 analysis by means of gamma-ray spectroscopy is described.« less

  5. Bioleaching remediation of heavy metal-contaminated soils using Burkholderia sp. Z-90.

    PubMed

    Yang, Zhihui; Zhang, Zhi; Chai, Liyuan; Wang, Yong; Liu, Yi; Xiao, Ruiyang

    2016-01-15

    Bioleaching is an environment-friendly and economical technology to remove heavy metals from contaminated soils. In this study, a biosurfactant-producing strain with capacity of alkaline production was isolated from cafeteria sewer sludge and its capability for removing Zn, Pb, Mn, Cd, Cu, and As was investigated. Phylogenetic analysis using 16S rDNA gene sequences confirmed that the strain belonged to Burkholderia sp. and named as Z-90. The biosurfactant was glycolipid confirmed by thin layer chromatography and Fourier-transform infrared spectroscopy. Z-90 broth was then used for bioleaching remediation of heavy metal-contaminated soils. The removal efficiency was 44.0% for Zn, 32.5% for Pb, 52.2% for Mn, 37.7% for Cd, 24.1% for Cu and 31.6% for As, respectively. Mn, Zn and Cd were more easily removed from soil than Cu, Pb and As, which was attributed to the presence of high acid-soluble fraction of Mn, Zn and Cd and high residual fraction of Cu, Pb and As. The heavy metal removal in soils was contributed to the adhesion of heavy metal-contaminated soil minerals with strain Z-90 and the formation of a metal complex with biosurfactant. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Ameliorants to immobilize Cd in rice paddy soils contaminated by abandoned metal mines in Korea.

    PubMed

    Ok, Yong Sik; Kim, Sung-Chul; Kim, Dong-Kuk; Skousen, Jeffrey G; Lee, Jin-Soo; Cheong, Young-Wook; Kim, Su-Jung; Yang, Jae E

    2011-01-01

    The cadmium (Cd) content of rice grain grown in metal-contaminated paddy soils near abandoned metal mines in South Korea was found to exceed safety guidelines (0.2 mg Cd kg⁻¹) set by the Korea Food and Drug Administration (KFDA). However, current remediation technologies for heavy metal-contaminated soils have limited application with respect to rice paddy soils. Laboratory and greenhouse experiments were conducted to assess the effects of amending contaminated rice paddy soils with zerovalent iron (ZVI), lime, humus, compost, and combinations of these compounds to immobilize Cd and inhibit Cd translocation to rice grain. Sequential extraction analysis revealed that treatment with the ameliorants induced a 50-90% decrease in the bioavailable Cd fractions when compared to the untreated control soil. When compared to the control, Cd uptake by rice was decreased in response to treatment with ZVI + humus (69%), lime (65%), ZVI + compost (61%), compost (46%), ZVI (42%), and humus (14%). In addition, ameliorants did not influence rice yield when compared to that of the control. Overall, the results of this study indicated that remediation technologies using ameliorants effectively reduce Cd bioavailability and uptake in contaminated rice paddy soils.

  7. Comparison of solid-phase bioassays and ecoscores to evaluate the toxicity of contaminated soils.

    PubMed

    Lors, Christine; Ponge, Jean-François; Martínez Aldaya, Maite; Damidot, Denis

    2010-08-01

    Five bioassays (inhibition of lettuce germination and growth, earthworm mortality, inhibition of springtail population growth, avoidance by springtails) were compared, using four coke factory soils contaminated by PAHs and trace elements, before and after biotreatment. For each bioassay, several endpoints were combined in an 'ecoscore', a measure of test sensitivity. Ecoscores pooled over all tested bioassays revealed that most organisms were highly sensitive to the concentration of 3-ring PAHs. When four soils were combined, behavioural tests using the springtail Folsomia candida showed higher ecoscores, i.e. they were most sensitive to soil contamination. However, despite overall higher sensitivity of behavioural tests, which could be used for cheap and rapid assessment of soil toxicity, especially at low levels of contamination, some test endpoints were more sensitive than others, and this may differ from a soil to another, pointing to the need for a battery of bioassays when more itemized results are expected. Copyright 2010 Elsevier Ltd. All rights reserved.

  8. Comparative study of rhizobacterial community structure of plant species in oil-contaminated soil.

    PubMed

    Lee, Eun-Hee; Cho, Kyong-Suk; Kim, Jaisoo

    2010-09-01

    In this study, the identity and distribution of plants and the structure of their associated rhizobacterial communities were examined in an oil-contaminated site. The number of plant species that formed a community or were scattered was 24. The species living in soil highly contaminated with total petroleum hydrocarbon (TPH) (9,000-4,5000 mg/g-soil) were Cynodon dactylon, Persicaria lapathifolia, and Calystegia soldanella (a halophytic species). Among the 24 plant species, the following have been known to be effective for oil removal: C. dactylon, Digitaria sanguinalis, and Cyperus orthostachyus. Denaturing gradient gel electrophoresis (DGGE) profile analysis showed that the following pairs of plant species had highly similar (above 70%) rhizobacterial community structures: Artemisia princeps and Hemistepta lyrata; C. dactylon and P. lapathifolia; Carex kobomugi and Cardamine flexuosa; and Equisetum arvense and D. sanguinalis. The major groups of rhizobacteria were Betaproteobacteria, Gamma-proteobacteria, Chloroflexi, Actinobacteria, and unknown. Based on DGGE analysis, P. lapathifolia, found for the first time in this study growing in the presence of high TPH, may be a good species for phytoremediation of oil-contaminated soils and in particular, C. soldanella may be useful for soils with high TPH and salt concentrations. Overall, this study suggests that the plant roots, regardless of plant species, may have a similar influence on the bacterial community structure in oil-contaminated soil.

  9. Assessment of groundwater, soil-gas, and soil contamination at the Vietnam Armor Training Facility, Fort Gordon, Georgia, 2009-2011

    USGS Publications Warehouse

    Guimaraes, Wladmir B.; Falls, W. Fred; Caldwell, Andral W.; Ratliff, W. Hagan; Wellborn, John B.; Landmeyer, James E.

    2012-01-01

    The U.S. Geological Survey, in cooperation with the U.S. Department of the Army Environmental and Natural Resources Management Office of the U.S. Army Signal Center and Fort Gordon, Georgia, assessed the groundwater, soil gas, and soil for contaminants at the Vietnam Armor Training Facility (VATF) at Fort Gordon, from October 2009 to September 2011. The assessment included the detection of organic compounds in the groundwater and soil gas, and inorganic compounds in the soil. In addition, organic contaminant assessment included organic compounds classified as explosives and chemical agents in selected areas. The assessment was conducted to provide environmental contamination data to the U.S. Army at Fort Gordon pursuant to requirements of the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. This report is a revision of "Assessment of soil-gas, surface-water, and soil contamination at the Vietnam Armor Training Facility, Fort Gordon, Georgia, 2009-2010," Open-File Report 2011-1200, and supersedes that report to include results of additional samples collected in July 2011. Four passive samplers were deployed in groundwater wells at the VATF in Fort Gordon. Total petroleum hydrocarbons and benzene and octane were detected above the method detection level at all four wells. The only other volatile organic compounds detected above their method detection level were undecane and pentadecane, which were detected in two of the four wells. Soil-gas samplers were deployed at 72 locations in a grid pattern across the VATF on June 3, 2010, and then later retrieved on June 9, 2010. Total petroleum hydrocarbons were detected in 71 of the 72 samplers (one sampler was destroyed in the field and not analyzed) at levels above the method detection level, and the combined mass of benzene, toluene, ethylbenzene, and total xylene (BTEX) was detected above the detection level in 31 of the 71 samplers that were analyzed. Other volatile organic compounds

  10. Microbial and enzymatic activity of soil contaminated with azoxystrobin.

    PubMed

    Baćmaga, Małgorzata; Kucharski, Jan; Wyszkowska, Jadwiga

    2015-10-01

    The use of fungicides in crop protection still effectively eliminates fungal pathogens of plants. However, fungicides may dissipate to various elements of the environment and cause irreversible changes. Considering this problem, the aim of the presented study was to evaluate changes in soil biological activity in response to contamination with azoxystrobin. The study was carried out in the laboratory on samples of sandy loam with a pH of 7.0 in 1 Mol KCl dm(-3). Soil samples were treated with azoxystrobin in one of four doses: 0.075 (dose recommended by the manufacturer), 2.250, 11.25 and 22.50 mg kg(-1) soil DM (dry matter of soil). The control soil sample did not contain fungicide. Bacteria were identified based on 16S rRNA gene sequencing, and fungi were identified by internal transcribed spacer (ITS) region sequencing. The study revealed that increased doses of azoxystrobin inhibited the growth of organotrophic bacteria, actinomycetes and fungi. The fungicide also caused changes in microbial biodiversity. The lowest values of the colony development (CD) index were recorded for fungi and the ecophysiological (EP) index for organotrophic bacteria. Azoxystrobin had an inhibitory effect on the activity of dehydrogenases, catalase, urease, acid phosphatase and alkaline phosphatase. Dehydrogenases were found to be most resistant to the effects of the fungicide, while alkaline phosphatase in the soil recovered the balance in the shortest time. Four species of bacteria from the genus Bacillus and two species of fungi from the genus Aphanoascus were isolated from the soil contaminated with the highest dose of azoxystrobin (22.50 mg kg(-1)).

  11. Lead and Arsenic Uptake by Leafy Vegetables Grown on Contaminated Soils: Effects of Mineral and Organic Amendments

    PubMed Central

    McBride, Murray B.; Simon, Tobi; Tam, Geoffrey; Wharton, Sarah

    2015-01-01

    To assess strategies for mitigating Pb and As transfer into leafy vegetables from contaminated garden soils, we conducted greenhouse experiments using two field-contaminated soils amended with materials expected to reduce metal phytoavailability. Lettuce and mustard greens grown on these soils were analysed by ICP-MS, showing that some Pb and As transfer into the vegetables occurred from both soils tested, but plant Pb concentrations were highly variable among treatment replicates. Soil-to-plant transfer was more efficient for As than for Pb. Contamination of the leaves by soil particles probably accounted for most of the vegetable Pb, since plant Pb concentrations were correlated to plant tissue concentrations of the immobile soil elements Al and Fe. This correlation was not observed for vegetable As concentrations, evidence that most of the soil-to-plant transfer for this toxic metal occurred by root uptake and translocation into the above-ground tissues. A follow-up greenhouse experiment with lettuce on one of the two contaminated soils revealed a lower and less variable foliar Pb concentration than observed in the first experiment, with evidence of less soil particle contamination of the crop. This reduced transfer of Pb to the crop appeared to be a physical effect attributable to the greater biomass causing reduced overall exposure of the above-ground tissues to the soil surface. Attempts to reduce soil Pb and As solubility and plant uptake by amendment at practical rates with stabilizing materials including composts, peat, Ca phosphate, gypsum and Fe oxide, were generally unsuccessful. Only Fe oxide reduced soluble As in the soil, but this effect did not persist. Phosphate amendment rapidly increased soil As solubility but had no measurable effect on either soil Pb solubility or concentrations of Pb or As in the leafy vegetables. The ineffectiveness of these amendments in reducing Pb transfer into leafy vegetables is attributed in this study to the low

  12. Characterizing Soil Lead Contamination Near Streams in Oakland, California

    NASA Astrophysics Data System (ADS)

    Tanouye, D.

    2017-12-01

    Lead (Pb) contamination of soils, groundwater, and surface waters is a major concern because of the potential health risks related to accumulation of high levels of lead in blood. This is a pervasive issue in many low-income neighborhoods throughout the United States, and is documented to be particularly acute in West Oakland, California. The fate and transport of lead in the environment is largely dependent on how it will bind to various solids and compounds in solution. These adsorption mechanisms are a principal aspect of metal dissolution and chemical speciation. Stream channels are natural drainage areas for urban runoff, and may represent a hot spot for increased levels of lead. This study evaluates the environmental conditions at 15 sites near streams in West Oakland using in-situ soil sampling with the handheld X-Ray Fluorescence (XRF) analyzer to measure concentrations of lead in soil. Results from this study suggest that the levels of lead in soils near stream channels are generally lower than the regional regulatory screening level of 80 milligrams per kilogram (mg/kg), but the highest concentrations are found near stream banks. The spatial distribution can be explained by a contaminant transport process related to the presence of fluvial channels.

  13. Contamination of soils with heavy metals and metalloids and its ecological hazard (analytic review)

    NASA Astrophysics Data System (ADS)

    Vodyanitskii, Yu. N.

    2013-07-01

    According to the present-day ecotoxicologic data, hazardous heavy metals/metalloids form the following sequence in the soil: Se > Tl > Sb > Cd > V > Hg > Ni > Cu > Cr > As > Ba. This sequence differs from the well-known series of the hazardous heavy elements, in which the danger of Pb and Zn is exaggerated, whereas that of V, Sb, and Ba, is underestimated. Tl also should be included in the list of hazardous elements in the soil. At present, the stress is made on the investigation of heavy metals/metalloids in agricultural soils rather than in urban soils, as the former produce contaminated products poisoning both animals and humans. The main sources of soil contamination with heavy metals are the following: aerial deposition from stationary and moving sources; hydrogenic contamination from the industrial sewage discharging into water bodies; sewage sediments; organic and mineral fertilizers and chemicals for plant protection, tailing dumps of ash, slag, ores, and sludge. In addition to the impact on plants and groundwater, heavy metals/metalloids exert a negative effect on the soil proper. Soil microorganisms appear to be very sensitive to the influence of heavy elements.

  14. Geoelectrical mapping of the Soil and Groundwater Contaminated Site: Case Study from Taiwan

    NASA Astrophysics Data System (ADS)

    Liu, H. C.; Lin, C. P.; Wang, T. P.

    2016-12-01

    In recent years, geophysical technology has been widely used in soil and groundwater investigation and remediation of contaminated sites assessments in Taiwan, such technology can securely work in either small or large sampler areas, and collect data from the traditional one-dimensional data to two-dimensional and three-dimensional data. In other words, geophysical technology helps provide more information to assist the data interpretation, and improves the overall effectiveness of soil and groundwater contamination surveys. Electrical Resistivity Tomography (ERT) is one of useful geophysical technology to the soil and groundwater contaminated sites. By estimating the groundwater flow direction and distribution of contaminations, we could establish monitoring or sampling wells in potential pollution areas. ERT survey could delineate the contaminated areas with high concentrations in relatively simple sites. Even in the seriously DNAPL leakage cases, it is possible to directly detect the DNAPL pool. In this study, we presented the investigation outcomes of electrical resistivity tomography (ERT) and ground-penetrating radar (GPR) at the DNAPLs-impacted site. Evaluation of ERT/GPR technique deployment in detecting buried DNAPLs and assessment of remediation efforts are also discussed. Results indicated zones with anomalously high resistivity to be associated with contaminated DNAPLs presence. Resistivity maps clearly outlined the subsurface distribution and the possible migration path of DNAPLs.

  15. Biotesting of radioactively contaminated forest soils using barley-based bioassay

    NASA Astrophysics Data System (ADS)

    Mel'nikova, T. V.; Polyakova, L. P.; Oudalova, A. A.

    2017-01-01

    Findings from radioactivity and phytotoxicity study are presented for soils from nine study-sites of the Klintsovsky Forestry located in the Bryansk region that were radioactively contaminated after the Chernobyl accident. According to the bioassay based on barley as test-species, stimulating effect of the soils analyzed is revealed for biological indexes of the length of barley roots and sprouts. From data on 137Cs specific activities in soils and plant biomass, the migration potential of radionuclide in the "soil-plant" system is assessed as a transfer factor. With correlation analysis, an impact of 137Cs in soil on the biological characteristics of barley is estimated.

  16. Radiostrontium contamination of soil and vegetation within the Semipalatinsk test site.

    PubMed

    Howard, B J; Semioschkina, N; Voigt, G; Mukusheva, M; Clifford, J

    2004-12-01

    The Semipalatinsk nuclear test site (STS) in the Republic of Kazakhstan was an important site for testing atomic bombs and other civil and military nuclear devices of the former Soviet Union. Results are presented from investigations on the extent of radiostrontium contamination in soils and vegetation at the technical areas of the STS, where the tests were conducted and in pastures used by farmers for grazing animals or for hay production. Our data are compared with those reported largely in the recent Russian language literature that has been reviewed. The extent of (90)Sr contamination of soil is highly variable over the STS with the highest values associated with the technical areas, particularly the Degelen mountains. Recently measured values in both the present data and the Russian language literature confirm the relatively high current contamination of soil and vegetation in the vicinity of tunnels and associated watercourses in the Degelen area. The proportion of (90)Sr in soil which could not be extracted with 6 M HCl was only an average of 20%, which is low compared to other test site areas and possibly indicates a relatively high mobility in this area, because the (90)Sr is derived from leakage from explosion tunnels along watercourses rather than being associated with fused silicates. A comparison of relative activity concentrations in soil and vegetation suggests that the transfer of (90)Sr to vegetation on the STS is high compared to that of (137)Cs and plutonium.

  17. Thermal removal of pyrene contamination from soil: basic studies and environmental health implications.

    PubMed Central

    Saito, H H; Bucalá, V; Howard, J B; Peters, W A

    1998-01-01

    Effects of temperature (400-1000 degrees C) and rate of heating to 550 degrees C (100, 1000, 5000 degrees C/sec) on reduction of pyrene contamination in a Superfund-related soil and on yields of volatile products (tars, CO, CO2, methane, acetylene, ethylene) have been measured. Fifty (+/- 3)-milligram thin layers (less than or equal to 150 micron) of 63- to 125-micron soil particles, neat (i.e., without exogenous chemicals), or pretreated with 4.75 wt% of pyrene, were heated for about 1 to 6 sec, under 3 psig (pounds per in.(2) gauge) of helium in a 12-liter sealed chamber. Pyrene removal, defined as the difference in weight loss of neat versus contaminated soil, was virtually immune to heating rate but increased strongly with increasing temperature, approaching 100% at about 530 degrees C. However, for pyrenepolluted soil, excess soil weight loss and modified CO yields were observed above about 500 degrees C for a 1000 degrees C/sec heating rate. These observations suggest that soil chemical reactions with pyrene or pyrene decomposition products augment soil volatilization. Consequently at elevated temperatures, the difference in weight loss protocol may overestimate polycyclic aromatic hydrocarbon (PAH) removal from soil. Increasing heating rate caused yields of CO, CO(2), and acetylene from pyrene-polluted soil to pass through maxima. Heating neat or contaminated soil resulted in at least two gaseous products of particular environmental interest:acetylene, a precursor to PAH in thermal synthesis, and CO, a toxin to human hemoglobin. Images Figure 1 Figure 2 PMID:9703498

  18. Effect of acid rain pH on leaching behavior of cement stabilized lead-contaminated soil.

    PubMed

    Du, Yan-Jun; Wei, Ming-Li; Reddy, Krishna R; Liu, Zhao-Peng; Jin, Fei

    2014-04-30

    Cement stabilization is a practical approach to remediate soils contaminated with high levels of lead. However, the potential for leaching of lead out of these stabilized soils under variable acid rain pH conditions is a major environmental concern. This study investigates the effects of acid rain on the leaching characteristics of cement stabilized lead contaminated soil under different pH conditions. Clean kaolin clay and the same soil spiked with 2% lead contamination are stabilized with cement contents of 12 and 18% and then cured for 28 days. The soil samples are then subjected to a series of accelerated leaching tests (or semi-dynamic leaching tests) using a simulated acid rain leachant prepared at pH 2.0, 4.0 or 7.0. The results show that the strongly acidic leachant (pH ∼2.0) significantly altered the leaching behavior of lead as well as calcium present in the soil. However, the differences in the leaching behavior of the soil when the leachant was mildly acidic (pH ∼4.0) and neutral (pH ∼7.0) prove to be minor. In addition, it is observed that the lead contamination and cement content levels can have a considerable impact on the leaching behavior of the soils. Overall, the leachability of lead and calcium is attributed to the stability of the hydration products and their consequent influence on the soil buffering capacity and structure. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Phosphate Treatment of Lead-Contaminated Soil: Effects on Water Quality, Plant Uptake, and Lead Speciation

    EPA Science Inventory

    Water quality threats associated with using phosphate-based amendments to remediate Pb-contaminated soils are a concern, particularly in riparian areas. This study investigated the effects of P application rates to a Pb-contaminated alluvial soil on Pb and P loss via surface wat...

  20. Risk of antibiotic resistance from metal contaminated soils

    NASA Astrophysics Data System (ADS)

    Knapp, Charles

    2013-04-01

    It is known that contaminated soils can lead to increased incidence of illness and disease, but it may also prevent our ability to fight disease. Many antibiotic resistant genes (ARG) acquired by bacteria originate from the environment. It is important to understand factors that influence levels of ARG in the environment, which could affect us clinically and agriculturally. The presence of elevated metal content in soils often promotes antibiotic resistance in exposed microorganisms. Using qPCR, the abundances of ARG to compare levels with geochemical conditions in randomly selected soils from several countries. Many ARG positively correlated with soil metal content, especially copper, chromium, nickel, lead, and iron. Results suggest that geochemical metal conditions influence the potential for antibiotic resistance in soil, which might be used to estimate baseline gene presence on various landscape scales and may translate to epidemiological risk of antibiotic-resistance transmission from the environment. This suggests that we may have to reconsider tolerances of metal pollution in the environment.

  1. Geochemical cartography as a tool for assessing the degree of soil contamination with heavy metals in Poland

    NASA Astrophysics Data System (ADS)

    Szymon Borkowski, Andrzej; Kwiatkowska-Malina, Jolanta

    2016-04-01

    Spatial disposition of chemical elements including heavy metals in the soil environment is a very important information during preparation of the thematic maps for the environmental protection and/or spatial planning. This knowledge is also essential for the earth's surface and soil's monitoring, designation of areas requiring improvement including remediation. The main source of anthropogenic pollution of soil with heavy metals are industry related to the mining coal and liquid fuels, mining and metallurgy, chemical industry, energy production, waste management, agriculture and transport. The geochemical maps as a kind of specific thematic maps made on the basis of datasets obtained from the Polish Geological Institute's resources allow to get to know the spatial distribution of different chemical elements including heavy metals in soil. The results of the research carried out by the Polish Geological Institute showed strong contamination in some regions in Poland mainly with arsenic, cadmium, lead and nickel. For this reason it was the point to prepare geochemical maps showing contamination of soil with heavy metals, and determine main sources of contamination and zones where heavy metals concentration was higher than acceptable contents. It was also presented a summary map of soil contamination with heavy metals. Additionally, location of highly contaminated zones was compiled with predominant in those areas types of arable soils and then results were thoroughly analyzed. This information can provide a base for further detailed studies on the soil contamination with heavy metals.

  2. An approach for mapping the vulnerability of European Union soils to antibiotic contamination.

    PubMed

    de la Torre, Ana; Iglesias, Irene; Carballo, Matilde; Ramírez, Pablo; Muñoz, María Jesús

    2012-01-01

    Release of antibiotics into the environment through the agricultural reuse of animal manure is considered a cause of chronic environmental exposure that often leads to adverse ecotoxicological effects, as well as to the introduction of antibiotic-resistant bacteria into the environment. The vulnerability of soil to antibiotic contamination plays a major role in determining the extent of the contamination and the likelihood of the emergence of antibiotic resistance and the appearance of ecotoxicological effects. It depends on soil characteristics, which vary across Europe, and antibiotic characteristics, which vary across drug classes. Understanding how soil vulnerability varies geographically for different veterinary medicinal products would be very useful for resource allocation among surveillance programmes. This paper performs risk analysis of the EU region for 12 antimicrobials using a spatial assessment performed in four steps. First, antibiotic release was estimated based on livestock density. Then exposure was estimated based on antimicrobial soil contamination. Third, consequences were modelled based on soil uses. Finally, risk was estimated by combining release, exposure and consequences using spatial multicriteria decision analysis. A final risk value for soil vulnerability was calculated for each antibiotic studied and displayed in chloropletic maps (ArcGIS 9.3). Furthermore, the Getis-Ord Gi statistic was used to identify clusters of areas at high risk for antibiotic soil contamination. Enrofloxacin was the highest-risk antibiotic in the European Union, followed by tetracyclines, tylosin and sulfodiazine. The highest risk values were found in Belgium, Ireland, Netherlands, Switzerland, Denmark, Germany and the UK. The results suggest that this methodology can be used successfully for evaluating the contamination potential of antibiotics over large areas with limited input data. This work is a preliminary step towards prioritising the use of veterinary

  3. Study of the mechanism of remediation of Cd-contaminated soil by novel biochars.

    PubMed

    Tan, Zhongxin; Wang, Yuanhang; Zhang, Limei; Huang, Qiaoyun

    2017-11-01

    This article used novel non-magnetized and magnetized biochars prepared under a CO 2 atmosphere returned to Cd-contaminated soil and compared these to the effects of conventional biochars prepared under a N 2 atmosphere with regard to Cd-contaminated soil remediation. A pot experiment with lettuce (Lactuca sativa) was conducted to investigate the relative soil remediation effects of these biochars. The soil used for the pot experiment was spiked with 20 mg kg -1 Cd and amended with 5% of a biochar before sowing. Through these research works, some important results were obtained as follows: (1) applying biochar treated by pyrolysis under a CO 2 atmosphere can obtain the best remediation effect of Cd-contaminated soil that the content of cadmium in the lettuce roots, stems, and leaves was reduced 67, 62, and 63%, respectively; (2) the magnetic biochar aggregation for the soil is weak, so the heavy metal cadmium in the soil could not be immobilized well by the magnetic biochar; (3) The remediation mechanism of novel biochars is that biochar includes a large number of organic functional groups (-C-OH, -C=O, COO-) that can act in a complexing reaction with heavy metal Cd(II) and the inorganic salt ions (Si, S, Cl, etc.) that can combine with cadmium and generate a stable combination.

  4. Remediating pesticide contaminated soils using solvent extraction

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sahle-Demessie, E.; Meckes, M.C.; Richardson, T.L.

    Bench-scale solvent extraction studies were performed on soil samples obtained from a Superfund site contaminated with high levels of p,p{prime}-DDT, p,p{prime}-DDE and toxaphene. The effectiveness of the solvent extraction process was assessed using methanol and 2-propanol as solvents over a wide range of operating conditions. It was demonstrated that a six-stage methanol extraction using a solvent-to-soil ratio of 1.6 can decrease pesticide levels in the soil by more than 99% and reduce the volume of material requiring further treatment by 25 times or more. The high solubility of the pesticides in methanol resulted in rapid extraction rates, with the systemmore » reaching quasi-equilibrium state in 30 minutes. The extraction efficiency was influenced by the number of extraction stages, the solvent-to-soil ratio, and the soil moisture content. Various methods were investigated to regenerate and recycle the solvent. Evaporation and solvent stripping are low cost and reliable methods for removing high pesticide concentrations from the solvent. For low concentrations, GAC adsorption may be used. Precipitating and filtering pesticides by adding water to the methanol/pesticide solution was not successful when tested with soil extracts. 26 refs., 10 figs., 6 tabs.« less

  5. Reclamation of petrol oil contaminated soil by rhamnolipids producing PGPR strains for growing Withania somnifera a medicinal shrub.

    PubMed

    Kumar, Rajesh; Das, Amar Jyoti; Juwarkar, Asha A

    2015-02-01

    Soil contaminated by hydrocarbons, cannot be used for agricultural intents due to their toxic effect to the plants. Surfactants producing by plant growth promotory rhizobacteria (PGPR) can effectively rig the problem of petroleum hydrocarbon contamination and growth promotion on such contaminated soils. In the present study three Pseudomonas strains isolated from contaminated soil identified by 16S rRNA analysis were ascertained for PGPR as well as biosurfactants property. Biosurfactants produced by the strains were further characterized and essayed for rhamnolipids. Inoculation of the strains in petrol hydrocarbon contaminated soil and its interaction with Withania somnifera in presence of petrol oil hydrocarbons depict that the strains helped in growth promotion of Withania somnifera in petrol oil contaminated soil while rhamnolipids helped in lowering the toxicity of petrol oil. The study was found to be beneficial as the growth and antioxidant activity of Withania sominfera was enhanced. Hence the present study signifies that rhamnolipids producing PGPR strains could be a better measure for reclamation of petrol contaminated sites for growing medicinal plants.

  6. Metal contamination disturbs biochemical and microbial properties of calcareous agricultural soils of the Mediterranean area.

    PubMed

    de Santiago-Martín, Ana; Cheviron, Natalie; Quintana, Jose R; González, Concepción; Lafuente, Antonio L; Mougin, Christian

    2013-04-01

    Mediterranean climate characteristics and carbonate are key factors governing soil heavy-metal accumulation, and low organic matter (OM) content could limit the ability of microbial populations to cope with resulting stress. We studied the effects of metal contamination on a combination of biological parameters in soils having these characteristics. With this aim, soils were spiked with a mixture of cadmium, copper, lead, and zinc, at the two limit values proposed by current European legislation, and incubated for ≤12 months. Then we measured biochemical (phosphatase, urease, β-galactosidase, arylsulfatase, and dehydrogenase activities) and microbial (fungal and bacterial DNA concentration by quantitative polymerase chain reaction) parameters. All of the enzyme activities were strongly affected by metal contamination and showed the following inhibition sequence: phosphatase (30-64 %) < arylsulfatase (38-97 %) ≤ urease (1-100 %) ≤ β-galactosidase (30-100 %) < dehydrogenase (69-100 %). The high variability among soils was attributed to the different proportion of fine mineral fraction, OM, crystalline iron oxides, and divalent cations in soil solution. The decrease of fungal DNA concentration in metal-spiked soils was negligible, whereas the decrease of bacterial DNA was ~1-54 % at the lowest level and 2-69 % at the highest level of contamination. The lowest bacterial DNA decrease occurred in soils with the highest OM, clay, and carbonate contents. Finally, regarding the strong inhibition of the biological parameters measured and the alteration of the fungal/bacterial DNA ratio, we provide strong evidence that disturbance on the system, even within the limiting values of contamination proposed by the current European Directive, could alter key soil processes. These limiting values should be established according to soil characteristics and/or revised when contamination is produced by a mixture of heavy metals.

  7. Assessment of trace element contamination of urban surface soil at informal industrial sites in a low-income country.

    PubMed

    Kanda, Artwell; Ncube, France; Hwende, Tamuka; Makumbe, Peter

    2018-05-29

    Trace elements released by human activity are ubiquitously detected in surface soil. The trace element contamination statuses of 20 sampling stations at two busy informal industrial sites of Harare city, Zimbabwe, were evaluated using geochemical indices. Spectrophotometric determinations of concentrations of trace elements in surface soil indicated generally higher values than the reference site and the average upper earth's crust. High contamination factors were observed for trace elements across sampling stations at Gazaland and Siyaso informal industrial sites. Concentrations exhibited heterogeneous distribution of trace elements in surface soil varying with the nature of activity at a sampling station. The pollution load index and degree of contamination suggested highly contaminated surface soil with Cd, Cu and Pb particularly where the following activities were done: (1) welding, (2) automobile maintenance and (3) waste dumping. These results may be very important to reduce soil contamination. Paving surfaces may help to reduce dispersal of trace elements deposited on surface soil to other stations and minimise human exposure via inhalation and contact.

  8. Viability of a nanoremediation  process in single or multi-metal(loid) contaminated soils.

    PubMed

    Gil-Díaz, M; Pinilla, P; Alonso, J; Lobo, M C

    2017-01-05

    The effectiveness of single- and multi-metal(loid) immobilization of As, Cd, Cr, Pb and Zn using different doses of nanoscale zero-valent iron (nZVI) was evaluated and compared in two different soils, a calcareous and an acidic one. The effectiveness of nZVI to immobilize metal(loid)s in soil strongly depended on the metal characteristics, soil properties, dose of nZVI and presence of other metal(loid)s. In the case of single contamination, this nanoremediation strategy was effective for all of the metal(loid)s studied except for Cd. When comparing the two soils, anionic metal(loid)s (As and Cr) were more easily retained in acidic soil, whereas cationic metal(loid)s (Cd, Pb and Zn), were immobilized more in calcareous soil. In multi-metal(loid) contaminated soils, the presence of several metal(loid)s affected their immobilization, which was probably due to the competitive phenomenon between metal(loid) ions, which can reduce their sorption or produce synergistic effects. At 10% of nZVI, As, Cr and Pb availability decreased more than 82%, for Zn it ranged between 31 and 75% and for Cd between 13 and 42%. Thus, the application of nZVI can be a useful strategy to immobilize As, Cr, Pb and Zn in calcareous or acidic soils in both single- or multi-metal(loid) contamination conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Greenhouse study on the phytoremediation potential of vetiver grass, Chrysopogon zizanioides L., in arsenic-contaminated soils.

    PubMed

    Datta, Rupali; Quispe, Mario A; Sarkar, Dibyendu

    2011-01-01

    The purpose of this greenhouse study was to assess the capacity of vetiver grass to accumulate arsenic from pesticide-contaminated soils of varying physico-chemical properties. Results indicate that vetiver is capable of tolerating moderate levels of arsenic up to 225 mg/kg. Plant growth and arsenic removal efficiency was strongly influenced by soil properties. Arsenic removal was highest (10.6%) in Millhopper soil contaminated with 45 mg/kg arsenic, which decreased to 4.5 and 0.6% at 225 and 450 mg/kg, respectively. High biomass, widespread root system and environmental tolerance make this plant an attractive choice for the remediation of soils contaminated with moderate levels of arsenic.

  10. Horizontal and vertical variability of soil properties in a trace element contaminated area

    NASA Astrophysics Data System (ADS)

    Burgos, Pilar; Madejón, Engracia; Pérez-de-Mora, Alfredo; Cabrera, Francisco

    2008-02-01

    The spatial distribution of some soil chemical properties and trace element contents of a plot affected by the Aznalcóllar mine spill were investigated using statistical and geostatistical methods to assess the extent of soil contamination. Total and EDTA-extractable soil trace element concentrations and total S content showed great variability and high coefficients of variation in the three examined depths. Soil in the plot was found to be significantly contaminated by As, Cd, Cu, Pb and Zn within a wide range of pH. Total trace element concentrations at all depths (0-60 cm) were much higher than background values of non-affected soil, indicating that despite the clean-up operations, the concentration of trace elements in the experimental plot was still high. The spatial distribution of the different variables was estimated by kriging to design contour maps. These maps allowed the identification of specific zones with high metal concentrations and low pH values corresponding to spots of residual sludge. Moreover, kriged maps showed distinct spatial distribution and hence different behaviour for the elements considered. This information may be applied to optimise remediation strategies in highly and moderately contaminated areas.

  11. Caenorhabditis elegans Predation on Bacillus anthracis: Decontamination of Spore Contaminated Soil with Germinants and Nematodes.

    PubMed

    Schelkle, Bettina; Choi, Young; Baillie, Leslie W; Richter, William; Buyuk, Fatih; Celik, Elif; Wendling, Morgan; Sahin, Mitat; Gallagher, Theresa

    2017-01-01

    Remediation of Bacillus anthracis -contaminated soil is challenging and approaches to reduce overall spore levels in environmentally contaminated soil or after intentional release of the infectious disease agent in a safe, low-cost manner are needed. B. anthracis spores are highly resistant to biocides, but once germinated they become susceptible to traditional biocides or potentially even natural predators such as nematodes in the soil environment. Here, we describe a two-step approach to reducing B. anthracis spore load in soil during laboratory trials, whereby germinants and Caenorhabditis elegans nematodes are applied concurrently. While the application of germinants reduced B. anthracis spore load by up to four logs depending on soil type, the addition of nematodes achieved a further log reduction in spore count. These laboratory based results suggest that the combined use of nematodes and germinants could represent a promising approach for the remediation of B. anthracis spore contaminated soil. Originality-Significance Statement: This study demonstrates for the first time the successful use of environmentally friendly decontamination methods to inactivate Bacillus anthracis spores in soil using natural predators of the bacterium, nematode worms.

  12. Phytostabilization—Management Strategy for Stabilizing Trace Elements in Contaminated Soils

    PubMed Central

    Vaverková, Magdalena D.; Baryła, Anna

    2017-01-01

    Contamination of soil by copper (Cu) has become a serious problem throughout the world, causing the reduction of agricultural yield and harmful effects on human health by entering the food chain. A glasshouse pot experiment was designed to evaluate the potential use of halloysite as an immobilizing agent in the aided phytostabilization of Cu-contaminated soil, using Festuca rubra L. The content of Cu in plants, i.e., total and extracted by 0.01 M CaCl2, was determined using the method of spectrophotometry. Cu content in the tested parts of F. rubra differed significantly when halloysite was applied to the soil, as well as with increasing concentrations of Cu. The addition of halloysite significantly increased plant biomass. Cu accumulated in the roots, thereby reducing its toxicity to the aerial parts of the plant. The obtained values of bioconcentration and translocation factors observed for halloysite treatment indicate the effectiveness of using F. rubra in phytostabilization techniques. PMID:28841169

  13. Calculation of dose distribution above contaminated soil

    NASA Astrophysics Data System (ADS)

    Kuroda, Junya; Tenzou, Hideki; Manabe, Seiya; Iwakura, Yukiko

    2017-07-01

    The purpose of this study was to assess the relationship between altitude and the distribution of the ambient dose rate in the air over soil decontamination area by using PHITS simulation code. The geometry configuration was 1000 m ×1000 m area and 1m in soil depth and 100m in altitude from the ground to simulate the area of residences or a school grounds. The contaminated region is supposed to be uniformly contaminated by Cs-137 γ radiation sources. The air dose distribution and space resolution was evaluated for flux of the gamma rays at each altitude, 1, 5, 10, and 20m. The effect of decontamination was calculated by defining sharpness S. S was the ratio of an average flux and a flux at the center of denomination area in each altitude. The suitable flight altitude of the drone is found to be less than 15m above a residence and 31m above a school grounds to confirm the decontamination effect. The calculation results can be a help to determine a flight planning of a drone to minimize the clash risk.

  14. [Effects of Remedies on the Remediation of Typical Pb and Zn-contaminated soil in Huanjiang, Guangxi].

    PubMed

    Zeng, Wei-quan; Song, Bo; Yuan, Li-zhu; Huang, Yu-fei; Fu, Feng-yan

    2015-06-01

    Due to the collapse of the Pb/Zn tailing dam of Huanjiang, Guangxi, the farmland along Huanjiang River are strongly acidic and heavy metal-contaminated, resulting in the loss of agricultural production. To explore some remedies and the migration of heavy metals in heavy metal contaminated-soil of Huanjiang, this study investigated the effects of different types of amendments (lime, calcium magnesium phosphate, organic fertilizer, polypropylene amide) on tested soils through soil leaching test. The results showed that T1 soil was severely acidified, reducing the pH of the soil layer to clean contact, while T2, T3, T4, T5 could significantly improve the contaminated soil pH, ranging from 2.7 to 3.2, 1.6 to 2.7 respectively. Compared with T1, in the contaminated soil at 0-20 cm, T2, T3, T4, T5 could effectively activate Pb and immobilize Zn. Compared with T1, in 20-60 cm clean soil, there was no significant differences in the effect of different treatments on DTPA-Pb and DTPA-Zn (P < 0.05). Compared with T1, T4 and T5 could provide good growing conditions for plants, which might provide technical support for future measurements such as bioremediation.

  15. Biaccumulation and tolerance of heavy metals on the tropical earthworm, Allobophora sp. after exposed to contaminated soil from oil mine waste

    NASA Astrophysics Data System (ADS)

    Suhendrayatna; Darusman; Raihannah; Nurmala, D.

    2018-04-01

    In this study, the impact of contaminated soil from oil mine waste on survival, behavior, tolerance, and bioaccumulation of heavy metals by the tropical earthworm, Allobophora sp. has been quantified. Earthworm was isolated from heavy metals-contaminated soil, cultured in laboratory condition, and exposed to contaminated soil from oil mine waste for a couple of months. The behavior and response of earthworms to contaminated soil was monitored for 28 days and evaluated by the response criteria was expressed in scale index (SI) referred to Langdon method. Resistance test of the earthworm (LC50) to heavy metals also conducted with variation soil concentrations of 100%, 50%, 25%, 12.5%, and 6.25%, and 0% (Control). Results showed that contaminated soil extremely affected to the earthworm live, especially length and their body weight. The Lethal Concentration 50% (LC50) of earthworm against contaminated soil was 19.05% (w/w). When exposed to contaminated soil, earthworm accumulated chromium, barium, and manganese at the concentration of 88; 92.2; and 280 mg/kg-DW, respectively. Based on these results, earthworm Allobophora sp. has potential to reduce heavy metals from contaminated soil in the field of bioremediation process.

  16. Polycyclic aromatic hydrocarbon removal from contaminated soils using fatty acid methyl esters.

    PubMed

    Gong, Zongqiang; Wang, Xiaoguang; Tu, Ying; Wu, Jinbao; Sun, Yifei; Li, Peng

    2010-03-01

    In this study, solubilization of PAHs from a manufactured gas plant (MGP) soil and two artificially spiked soils using fatty acid methyl esters (FAME) was investigated. PAH removals from both the MGP and the spiked soils by FAME, methanol, soybean oil, hydroxypropyl-beta-cyclodextrin, Triton X-100, and Tween 80 were compared. The effect of FAME:MGP soil ratios on PAH removals was also investigated. Results showed that the FAME mixture synthesized by our lab was more efficient than the cyclodextrin and the two surfactants used for PAH removal from the spiked soils with individual PAH concentrations of 200 and 400 mg kg(-1). However, the difference among three PAH removals by the FAME, soybean oil and methanol was not quite pronounced. The FAME synthesized and market biodiesel exhibited better performance for PAH removals (46% and 35% of total PAH) from the weathered contaminated MGP soil when compared with the other agents (0-31%). Individual PAH removals from the weathered MGP soil were much lower than those from the spiked soils. The percentages of total PAH removals from the MGP soil were 59%, 46%, and 51% for the FAME:MGP soil ratios of 1:2, 1:1, and 2:1, respectively. These results showed that the FAME could be a more attractive alternative to conventional surfactants in ex situ washing of PAH-contaminated soils. 2010 Elsevier Ltd. All rights reserved.

  17. Ricinus communis L. A Value Added Crop for Remediation of Cadmium Contaminated Soil.

    PubMed

    Bauddh, Kuldeep; Singh, Kripal; Singh, Rana P

    2016-02-01

    Heavy metal pollution of soil is a global environmental problem and therefore its remediation is of paramount importance. Cadmium (Cd) is a potential toxicant to living organisms and even at very low concentrations. This study was aimed to assess the effectiveness of Ricinus communis for remediation of Cd contaminated soils. For this, growth and biomass of R. communis and Cd accumulation, translocation and partitioning in different plant parts were investigated after 8 months of plant growth in Cd contaminated soil (17.50 mg Cd kg−1 soil). Eight months old plants stabilized 51 % Cd in its roots and rest of the metal was transferred to the stem and leaves. There were no significant differences in growth, biomass and yield between control and Cd treated plants, except fresh weight of shoots. The seed yield per plant was reduced only by 5 % of Cd contaminated plants than control. The amount of Cd translocated to the castor seeds was nominal i.e. 0.007 µg Cd g−1 seeds. The bioconcentration factor reduced significantly in shoots and seeds in comparison to roots. The data indicates that R. communis is highly tolerant to Cd contamination and can be used for remediation of heavy metal polluted sites.

  18. Phytoremediation of contaminated soils containing gasoline using Ludwigia octovalvis (Jacq.) in greenhouse pots.

    PubMed

    Al-Mansoory, Asia Fadhile; Idris, Mushrifah; Abdullah, Siti Rozaimah Sheikh; Anuar, Nurina

    2017-05-01

    Greenhouse experiments were carried out to determine the phytotoxic effects on the plant Ludwigia octovalvis in order to assess its applicability for phytoremediation gasoline-contaminated soils. Using plants to degrade hydrocarbons is a challenging task. In this study, different spiked concentrations of hydrocarbons in soil (1, 2, and 3 g/kg) were tested. The results showed that the mean efficiency of total petroleum hydrocarbon (TPH) removal over a 72-day culture period was rather high. The maximum removal of 79.8 % occurred for the 2 g/kg concentration, while the removal rate by the corresponding unplanted controls was only (48.6 %). The impact of gasoline on plants included visual symptoms of stress, yellowing, growth reduction, and perturbations in the developmental parameters. The dry weight and wet weight of the plant slightly increased upon exposure to gasoline until day 42. Scanning electron microscopy (SEM) indicated change to the root and stem structure in plant tissue due to the direct attachment with gasoline contaminated compared to the control sample. The population of living microorganisms in the contaminated soil was found to be able to adapt to different gasoline concentrations. The results showed that L. octovalvis and rhizobacteria in gasoline-contaminated soil have the potential to degrade organic pollutants.

  19. Long-Term Oil Contamination Alters the Molecular Ecological Networks of Soil Microbial Functional Genes

    PubMed Central

    Liang, Yuting; Zhao, Huihui; Deng, Ye; Zhou, Jizhong; Li, Guanghe; Sun, Bo

    2016-01-01

    With knowledge on microbial composition and diversity, investigation of within-community interactions is a further step to elucidate microbial ecological functions, such as the biodegradation of hazardous contaminants. In this work, microbial functional molecular ecological networks were studied in both contaminated and uncontaminated soils to determine the possible influences of oil contamination on microbial interactions and potential functions. Soil samples were obtained from an oil-exploring site located in South China, and the microbial functional genes were analyzed with GeoChip, a high-throughput functional microarray. By building random networks based on null model, we demonstrated that overall network structures and properties were significantly different between contaminated and uncontaminated soils (P < 0.001). Network connectivity, module numbers, and modularity were all reduced with contamination. Moreover, the topological roles of the genes (module hub and connectors) were altered with oil contamination. Subnetworks of genes involved in alkane and polycyclic aromatic hydrocarbon degradation were also constructed. Negative co-occurrence patterns prevailed among functional genes, thereby indicating probable competition relationships. The potential “keystone” genes, defined as either “hubs” or genes with highest connectivities in the network, were further identified. The network constructed in this study predicted the potential effects of anthropogenic contamination on microbial community co-occurrence interactions. PMID:26870020

  20. Stabilize lead and cadmium in contaminated soils using hydroxyapatite and potassium chloride.

    PubMed

    Wang, Li; Li, Yonghua; Li, Hairong; Liao, Xiaoyong; Wei, Binggan; Ye, Bixiong; Zhang, Fengying; Yang, Linsheng; Wang, Wuyi; Krafft, Thomas

    2014-12-01

    Combination of hydroxyapatite (HAP) and potassium chloride (KCl) was used to stabilize lead and cadmium in contaminated mining soils. Pot experiments of chilli (Capsicum annuum) and rape (Brassica rapachinensis) were used to evaluate the stabilization efficiency. The results were the following: (1) the optimal combination decreased the leachable lead by 83.3 and 97.27 %, and decreased leachable cadmium by 57.82 and 35.96% for soil HF1 and soil HF2, respectively; (2) the total lead and cadmium concentrations in both plants decreased 69 and 44 %, respectively; (3) The total lead and cadmium concentrations in the edible parts of both vegetables also decreased significantly. This study reflected that potassium chloride can improve the stabilization efficiency of hydroxyapatite, and the combination of hydroxyapatite and potassium chloride can be effectively used to remediate lead and cadmium contaminated mining soil.

  1. The effect of plants on the degradation and toxicity of petroleum contaminants in soil: a field assessment.

    PubMed

    Banks, M K; Schwab, P; Liu, B; Kulakow, P A; Smith, J S; Kim, R

    2003-01-01

    A field project located at the US Naval Base at Port Hueneme, California was designed to evaluate changes in contaminant concentrations and toxicity during phytoremediation. Vegetated plots were established in petroleum (diesel and heavy oil) contaminated soil and were evaluated over a two-year period. Plant species were chosen based on initial germination studies and included native California grasses. The toxicity of the impacted soil in vegetated and unvegetated plots was evaluated using Microtox, earthworm, and seed germination assays. The reduction of toxicity was affected more by contaminant aging than the establishment of plants. However, total petroleum hydrocarbon concentrations were lower by the end of the study in the vegetated plots when compared to the unvegetated soil. Although phytoremediation is an effective approach for cleaning-up of petroleum contaminated soil, a long-term management plan is required for significant reductions in contaminant concentrations.

  2. Effects of aging herbicide mixtures on soil respiration and plant survival in soils from a pesticide-contaminated site

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kruger, E.L.; Anhalt, J.C.; Anderson, T.A.

    Three herbicides, atrazine, metolachlor, and pendimethalin, were applied individually and in all possible combinations to soil taken from a pesticide-contaminated site in Iowa. The rate of application for each chemical was 50 {mu}g/g, representative of contamination problems at mixing and loading areas of agrochemical dealer sites. Treated soils were incubated at 24{degrees}C in the dark for 0, 21, and 63 d, and soil moisture tension was maintained at -33 kPa. Soil respiration was measured daily by using an infrared gas analyzer for 10 d at the end of each incubation period. Subsamples of treated soils were used in plant germinationmore » and survival studies. Concentrations of each herbicide were determined by gas chromatography at day 0, 21, and 63. Soil respiration was elevated for the first 6 d immediately following treatment, and then declined to very low levels. At the end of day 21 and 63, soil respiration remained at very low levels. The half-lives for atrazine, metolachlor, and pendimethalin individually in soil or in combination with one and/or the other herbicide will be reported. The results of germination and survival studies with kochia, giant foxtail, birdsfoot trefoil, crown vetch, and soybean will also be reported.« less

  3. Zinc speciation in proximity to phosphate application points in a lead/zinc smelter-contaminated soil.

    PubMed

    Baker, Lucas R; Pierzynski, Gary M; Hettiarachchi, Ganga M; Scheckel, Kirk G; Newville, Matthew

    2012-01-01

    The use of P to immobilize Pb in contaminated soils has been well documented. However, the influence of P on Zn speciation in soils has not been extensively examined, and these two metals often occur as co-contaminants. We hypothesized that additions of P to a Pb/Zn-contaminated soil would induce Zn phosphate mineral formation and fluid P sources would be more effective than granular P amendments. A combination of different synchrotron-based techniques, namely, spatially resolved micro-X-ray fluorescence (μ-XRF), micro-extended X-ray absorption fine structure spectroscopy (μ-EXAFS), and micro-X-ray diffraction (μ-XRD), were used to speciate Zn at two incubation times in the proximity of application points (0 to 4 mm) for fluid and granular P amendments in a Pb/Zn smelter-contaminated soil. Phosphate rock (PR), triple super phosphate (TSP), monoammonium phosphate (MAP), and fluid ammonium polyphosphate induced Zn phosphate formation. Ammonium polyphosphate was more effective at greater distances (up to 3.7 mm) from the point of P application. Phosphoric acid increased the presence of soluble Zn species because of increased acidity. Soluble Zn has implications with respect to Zn bioavailability, which may negatively impact vegetation and other sensitive organisms. Although additions of P immobilize Pb, this practice needs close monitoring due to potential increases in Zn solubility in a Pb/Zn smelter-contaminated soil. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  4. Dynamic Effects of Biochar on the Bacterial Community Structure in Soil Contaminated with Polycyclic Aromatic Hydrocarbons.

    PubMed

    Song, Yang; Bian, Yongrong; Wang, Fang; Xu, Min; Ni, Ni; Yang, Xinglun; Gu, Chenggang; Jiang, Xin

    2017-08-16

    Amending soil with biochar is an effective soil remediation strategy for organic contaminants. This study investigated the dynamic effects of wheat straw biochar on the bacterial community structure during remediation by high-throughput sequencing. The wheat straw biochar amended into the soil significantly reduced the bioavailability and toxicity of polycyclic aromatic hydrocarbons (PAHs). Biochar amendment helped to maintain the bacterial diversity in the PAH-contaminated soil. The relationship between the immobilization of PAHs and the soil bacterial diversity fit a quadratic model. Before week 12 of the incubation, the incubation time was the main factor contributing to the changes in the soil bacterial community structure. However, biochar greatly affected the bacterial community structure after 12 weeks of amendment, and the effects were dependent upon the biochar type. Amendment with biochar mainly facilitated the growth of rare bacterial genera (relative abundance of 0.01-1%) in the studied soil. Therefore, the application of wheat straw biochar into PAH-contaminated soil can reduce the environmental risks of PAHs and benefit the soil microbial ecology.

  5. Arsenic uptake by lettuce from As-contaminated soil remediated with Pteris vittata and organic amendment.

    PubMed

    de Oliveira, Letuzia M; Suchismita, Das; Gress, Julia; Rathinasabapathi, Bala; Chen, Yanshan; Ma, Lena Q

    2017-06-01

    Leaching of inorganic arsenic (As) from chromated copper arsenate (CCA)-treated wood may elevate soil As levels. Thus, an environmental concern arises regarding As accumulation in vegetables grown in these soils. In this study, a greenhouse experiment was conducted to investigate the ability of As-hyperaccumulator P. vittata and organic amendments in reducing As uptake by lettuce (Lactuca sativa) from a soil contaminated from CCA-treated wood (63.9 mg kg -1 As). P. vittata was grown for 150 d in a CCA-contaminated soil amended with biochar, activated carbon or coffee grounds at 1%, followed by lettuce for another 55 d. After harvest, plant biomass and As concentrations in plant and soil were determined. The presence of P. vittata reduced As content in lettuce by 21% from 27.3 to 21.5 mg kg -1 while amendment further reduced As in lettuce by 5.6-18%, with activated C being most effective. Our data showed that both P. vittata and organic amendments were effective in reducing As concentration in lettuce. Though no health-based standard for As in vegetables exists in USA, care should be taken when growing lettuce in contaminated soils. Our data showed that application of organic amendments with P. vittata reduced As hazards in CCA-contaminated soils. Published by Elsevier Ltd.

  6. A hierarchical approach to ecological assessment of contaminated soils at Aberdeen Proving Ground, USA

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kuperman, R.G.

    1995-12-31

    Despite the expansion of environmental toxicology studies over the past decade, soil ecosystems have largely been ignored in ecotoxicological studies in the United States. The objective of this project was to develop and test the efficacy of a comprehensive methodology for assessing ecological impacts of soil contamination. A hierarchical approach that integrates biotic parameters and ecosystem processes was used to give insight into the mechanisms that lead to alterations in the structure and function of soil ecosystems in contaminated areas. This approach involved (1) a thorough survey of the soil biota to determine community structure, (2) laboratory and field testsmore » on critical ecosystem processes, (3) toxicity trials, and (4) the use of spatial analyses to provide input to the decision-making, process. This methodology appears to, offer an efficient and potentially cost-saving tool for remedial investigations of contaminated sites.« less

  7. The effect of Piriformospora indica on the root development of maize (Zea mays L.) and remediation of petroleum contaminated soil.

    PubMed

    Zamani, Javad; Hajabbasi, Mohammad Ali; Alaie, Ebrahim; Sepehri, Mozhgan; Leuchtmann, Adrian; Schulin, Rainer

    2016-01-01

    As the depth of soil petroleum contamination can vary substantially under field conditions, a rhizotron experiment was performed to investigate the influence of endophyte, P. indica, on maize growth and degradation of petroleum components in a shallow and a deep-reaching subsurface layer of a soil. For control, a treatment without soil contamination was also included. The degree in contamination and the depth to which it extended had a strong effect on the growth of the plant roots. Contaminated soil layers severely inhibited root growth thus many roots preferred to bypass the shallow contaminated layer and grow in the uncontaminated soil. While the length and branching pattern of these roots were similar to those of uncontaminated treatment. Inoculation of maize with P. indica could improve root distribution and root and shoot growth in all three contamination treatments. This inoculation also enhanced petroleum degradation in soil, especially in the treatment with deep-reaching contamination, consequently the accumulation of petroleum hydrocarbons (PAHs) in the plant tissues were increased.

  8. [Recent advance in solidification/stabilization technology for the remediation of heavy metals-contaminated soil].

    PubMed

    Hao, Han-zhou; Chen, Tong-bin; Jin, Meng-gui; Lei, Mei; Liu, Cheng-wu; Zu, Wen-pu; Huang, Li-mi

    2011-03-01

    Remediation of heavy metals-contaminated soil is still a difficulty and a hotspot of international research projects. At present, the technologies commonly adopted for the remediation of contaminated sites mainly include excavation, solidification/stabilization (S/S), soil washing, soil vapor extraction (SVE), thermal treatment, and bioremediation. Based on the S/S technical guidelines of Unite State Environmental Protection Agency (EPA) and United Kingdom Environment Agency (EA) and the domestic and foreign patents, this paper introduced the concepts of S/S and its development status at home and abroad, and discussed its future development directions. Solidification refers to a process that binds contaminated media with a reagent, changing the media's physical properties via increasing its compressive strength, decreasing its permeability, and encapsulating the contaminants to form a solid material. Stabilization refers to the process that involves a chemical reaction which reduces the leachability of a waste, chemically immobilizes the waste and reduces its solubility, making the waste become less harmful or less mobile. S/S technology includes cement solidification, lime pozzolanic solidification, plastic materials stabilization, vitrification, and regent-based stabilization. Stabilization (or immobilization) treatment processes convert contaminants to less mobile forms through chemical or thermal interactions. In stabilization technology, the aim of adding agents is to change the soil physical and chemical properties through pH control technology, redox potential technology, precipitation techniques, adsorption technology, and ion-exchange technology that change the existing forms of heavy metals in soil, and thus, reduce the heavy metals bioavailability and mobility. This review also discussed the S/S evaluation methods, highlighted the need to enhance S/S technology in the molecular bonding, soil polymers, and formulation of China's S/S technical guidelines.

  9. Uptake of explosives from contaminated soil by existing vegetation at the Iowa Army Ammunition Plant

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Schneider, J.F.; Zellmer, S.D.; Tomczyk, N.A.

    This study examines the uptake of explosives by existing vegetation growing in soils contaminated with 2,4,6-trinitrotoluene (TNT) and 1,3,5-trinitro-3,5-triazine (RDX) in three areas at the Iowa Army Ammunition Plant (IAAP). To determine explosives uptake under natural environmental conditions, existing plant materials and soil from the root zone were sampled at different locations in each area, and plant materials were separated by species. Standard methods were used to determine the concentrations of explosives, their derivatives, and metabolites in the soil samples. Plant materials were also analyzed. The compound TNT was not detected in the aboveground portion of plants, and vegetation growingmore » on TNT-contaminated soils is not considered a health hazard. However, soil and plant roots may contain TNT degradation products that may be toxic; hence, their consumption is not advised. The compound RDX was found in the tops and roots of plants growing on RDX-contaminated soils at all surveyed sites. Although RDX is not a listed carcinogen, several of its potentially present degradation products are carcinogens. Therefore, the consumption of any plant tissues growing on RDX-contaminated sites should be considered a potential health hazard.« less

  10. The use of red mud as an immobiliser for metal/metalloid-contaminated soil: A review.

    PubMed

    Hua, Yumei; Heal, Kate V; Friesl-Hanl, Wolfgang

    2017-03-05

    This review focuses on the applicability of red mud as an amendment for metal/metalloid-contaminated soil. The varying properties of red muds from different sources are presented as they influence the potentially toxic element (PTE) concentration in amended soil. Experiments conducted worldwide from the laboratory to the field scale are screened and the influencing parameters and processes in soils are highlighted. Overall red mud amendment is likely to contribute to lowering the PTE availability in contaminated soil. This is attributed to the high pH, Fe and Al oxide/oxyhydroxide content of red mud, especially hematite, boehmite, gibbsite and cancrinite phases involved in immobilising metals/metalloids. In most cases red mud amendment resulted in a lowering of metal concentrations in plants. Bacterial activity was intensified in red mud-amended contaminated soil, suggesting the toxicity from PTEs was reduced by red mud, as well as indirect effects due to changes in soil properties. Besides positive effects of red mud amendment, negative effects may also appear (e.g. increased mobility of As, Cu) which require site-specific risk assessments. Red mud remediation of metal/metalloid contaminated sites has the potential benefit of reducing red mud storage and associated problems. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Natural attenuation processes for remediation of arsenic contaminated soils and groundwater.

    PubMed

    Wang, Suiling; Mulligan, Catherine N

    2006-12-01

    Arsenic (As) contamination presents a hazard in many countries. Natural attenuation (NA) of As-contaminated soils and groundwater may be a cost-effective in situ remedial option. It relies on the site intrinsic assimilative capacity and allows in-place cleanup. Sorption to solid phases is the principal mechanism immobilizing As in soils and removing it from groundwater. Hydroxides of iron, aluminum and manganese, clay and sulfide minerals, and natural organic matter are commonly associated with soils and aquifer sediments, and have been shown to be significant As adsorbents. The extent of sorption is influenced by As speciation and the site geochemical conditions such as pH, redox potential, and the co-occurring ions. Microbial activity may catalyze the transformation of As species, or mediate redox reactions thus influencing As mobility. Plants that are capable of hyperaccumulating As may translocate As from contaminated soils and groundwater to their tissues, providing the basis for phytoremediation. However, NA is subject to hydrological changes and may take substantial periods of time, thus requiring long-term monitoring. The current understanding of As NA processes remains limited. Sufficient site characterization is critical to the success of NA. Further research is required to develop conceptual and mathematical models to predict the fate and transport of As and to evaluate the site NA capacity. Engineering enhanced NA using environmentally benign products may be an effective alternative.

  12. [Improving Agricultural Safety of Soils Contaminated with Polycyclic Aromatic Hydrocarbons by In Situ Bioremediation].

    PubMed

    Jiao, Hai-huan; Pan, Jian-gang; Xu, Shena-jun; Bai, Zhi-hui; Wang, Dong; Huang, Zhan-bin

    2015-08-01

    In order to reduce the risk of enrichment of polycyclic aromatic hydrocarbons (PAHs) in crops, reduce the potential hazards of food-sourced PAHs to human and increase the agricultural safety of PAHs contaminated soils, the bio-augmented removal of polycyclic aromatic hydrocarbons (PAHs) was investigated through in situ remediation by introducing Rhodobacter sphaeroides (RS) into the agricultural soil contaminated by PAHs. The 50-times diluted RS was sprayed on leaf surface (in area B) or irrigated to roots (in area D). The treatment of spraying water of the equal amount was taken as the control (A) and the wheat field without any treatment as the blank (CK). Treatments were conducted since wheat seeding. Soil and wheat samples were collected in the mature period to analyze the changes of community structure of the soil microorganisms and the concentration of PAHs in soils and investigate the strengthening and restoration effects of RS on PAHs contaminated soils. Compared to the CK Area, the areas B and D revealed that the variation ratio of phospholipid fatty acids (PLFAs) that were the biomarker of soil microorganisms was 29.6%, and the ratio of total PAHs removed was increased 1.59 times and 1.68 times, respectively. The dry weight of wheat grain of 50 spikes was increased by 8.95% and 12.5%, respectively, and the enrichment factor of total PAHs was decreased by 58.9% and 62.2% respectively in the wheat grains. All the results suggested that RS reduced enrichment of PAHs in wheat grains and increased wheat yield, which had great exploitation and utilization potentiality in repairing and improving the agricultural safety of the soils contaminated with PHAs.

  13. Microbial communities to mitigate contamination of PAHs in soil--possibilities and challenges: a review.

    PubMed

    Fernández-Luqueño, F; Valenzuela-Encinas, C; Marsch, R; Martínez-Suárez, C; Vázquez-Núñez, E; Dendooven, L

    2011-01-01

    Although highly diverse and specialized prokaryotic and eukaryotic microbial communities in soil degrade polycyclic aromatic hydrocarbons (PAHs), most of these are removed slowly. This review will discuss the biotechnological possibilities to increase the microbial dissipation of PAHs from soil as well as the main biological and biotechnological challenges. Microorganism provides effective and economically feasible solutions for soil cleanup and restoration. However, when the PAHs contamination is greater than the microbial ability to dissipate them, then applying genetically modified microorganisms might help to remove the contaminant. Nevertheless, it is necessary to have a more holistic review of the different individual reactions that are simultaneously taking place in a microbial cell and of the interactions microorganism-microorganism, microorganism-plant, microorganism-soil, and microorganisms-PAHs. Elucidating the function of genes from the PAHs-polluted soil and the study in pure cultures of isolated PAHs-degrading organisms as well as the generation of microorganisms in the laboratory that will accelerate the dissipation of PAHs and their safe application in situ have not been studied extensively. There is a latent environmental risk when genetically engineered microorganisms are used to remedy PAHs-contaminated soil.

  14. MUTAGENICITY OF PAH-CONTAMINATED SOILS DURING BIOREMEDIATION

    EPA Science Inventory

    Bioremediation of contaminated soils is considered an effective method for reducing potential health hazards. Although it is assumed that (bio)remediation is a detoxifying process, degradation products of compounds such as polycyclic aromatic compounds (PACs) can be more toxic th...

  15. Soil solution Zn and pH dynamics in non-rhizosphere soil and in the rhizosphere of Thlaspi caerulescens grown in a Zn/Cd-contaminated soil.

    PubMed

    Luo, Y M; Christie, P; Baker, A J

    2000-07-01

    Temporal changes in soil solution properties and metal speciation were studied in non-rhizosphere soil and in the rhizosphere of the hyperaccumulator Thlaspi caerulescens J. & C. Presl (population from Prayon, Belgium) grown in a Zn- and Cd-contaminated soil. This paper focuses on soil solution Zn and pH dynamics during phytoextraction. The concentration of Zn in both non-rhizosphere and rhizosphere soil solutions decreased from 23 mg/l at the beginning to 2 mg/l at the end of the experiment (84 days after transplanting of seedlings), mainly due to chemical sorption. There was no significant difference in overall Zn concentration between the planted and the unplanted soil solutions (P > 0.05). Soil solution pH decreased initially and then increased slightly in both planted and unplanted soil zones. From 60 to 84 days after transplanting, the pH of the rhizosphere soil solution was higher than that of non-rhizosphere soil solution (P<0.05). Zn uptake by the hyperaccumulator plants was 8.8 mg per pot (each containing 1 kg oven-dry soil) on average. The data indicate that the potential of T. caerulescens to remove Zn from contaminated soil may not be related to acidification of the rhizosphere.

  16. Concentrations of arsenic, copper, cobalt, lead and zinc in cassava (Manihot esculenta Crantz) growing on uncontaminated and contaminated soils of the Zambian Copperbelt

    NASA Astrophysics Data System (ADS)

    Kříbek, B.; Majer, V.; Knésl, I.; Nyambe, I.; Mihaljevič, M.; Ettler, V.; Sracek, O.

    2014-11-01

    The concentrations of arsenic (As), copper (Cu), cobalt (Co), lead (Pb) and zinc (Zn) in washed leaves and washed and peeled tubers of cassava (Manihot esculenta Crantz, Euphorbiaceae) growing on uncontaminated and contaminated soils of the Zambian Copperbelt mining district have been analyzed. An enrichment index (EI) was used to distinguish between contaminated and uncontaminated areas. This index is based on the average ratio of the actual and median concentration of the given contaminants (As, Co, Cu, mercury (Hg), Pb and Zn) in topsoil. The concentrations of copper in cassava leaves growing on contaminated soils reach as much as 612 mg kg-1 Cu (total dry weight [dw]). Concentrations of copper in leaves of cassava growing on uncontaminated soils are much lower (up to 252 mg kg-1 Cu dw). The concentrations of Co (up to 78 mg kg-1 dw), As (up to 8 mg kg-1 dw) and Zn (up to 231 mg kg-1 dw) in leaves of cassava growing on contaminated soils are higher compared with uncontaminated areas, while the concentrations of lead do not differ significantly. The concentrations of analyzed chemical elements in the tubers of cassava are much lower than in its leaves with the exception of As. Even in strongly contaminated areas, the concentrations of copper in the leaves and tubers of cassava do not exceed the daily maximum tolerance limit of 0.5 mg kg-1/human body weight (HBW) established by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). The highest tolerable weekly ingestion of 0.025 mg kg-1/HBW for lead and the highest tolerable weekly ingestion of 0.015 mg kg-1/HBW for arsenic are exceeded predominantly in the vicinity of smelters. Therefore, the preliminary assessment of dietary exposure to metals through the consumption of uncooked cassava leaves and tubers has been identified as a moderate hazard to human health. Nevertheless, as the surfaces of leaves are strongly contaminated by metalliferous dust in the polluted areas, there is still a potential hazard

  17. Stability of immobilization remediation of several amendments on cadmium contaminated soils as affected by simulated soil acidification.

    PubMed

    Guo, Fuyu; Ding, Changfeng; Zhou, Zhigao; Huang, Gaoxiang; Wang, Xingxiang

    2018-06-04

    Chemical immobilization is a practical approach to remediate heavy metal contamination in agricultural soils. However, the potential remobilization risks of immobilized metals are a major environmental concern, especially in acid rain zones. In the present study, changes in the immobilization efficiency of several amendments as affected by simulated soil acidification were investigated to evaluate the immobilization remediation stability of several amendments on two cadmium (Cd) contaminated soils. Amendments (hydrated lime, hydroxyapatite and biochar) effectively immobilized Cd, except for organic fertilizer, and their immobilizations were strongly decreased by the simulated soil acidification. The ratio of changes in CaCl 2 -extractable Cd: pH (△CaCl 2 -Cd/△pH) can represent the Cd remobilization risk of different amended soils. Hydroxyapatite and biochar had a stronger durable immobilizing effect than did hydrated lime, particularly in soil with a lower pH buffering capacity, which was further confirmed by the Cd concentration and accumulation in lettuce. These results can be attributed to that hydroxyapatite and biochar transformed greater proportions of exchangeable Cd to other more stable fractions than lime. After 48 weeks of incubation, in soil with a lower pH buffering capacity, the immobilization efficiencies of lime, hydroxyapatite, biochar and organic fertilizer in the deionized water group (pH 6.5) were 71.7%, 52.7%, 38.6% and 23.9%, respectively, and changed to 19.1%, 33.6%, 26.5% and 5.0%, respectively, in the simulated acid rain group (pH 2.5). The present study provides a simple method to preliminarily estimate the immobilization efficiency of amendments and predict their stability in acid rain regions before large-scale field application. In addition, hydrated lime is recommended to be combined with other acid-stable amendments (such as hydroxyapatite or biochar) to remediate heavy metal-contaminated agricultural soils in acid precipitation

  18. Laboratory and greenhouse assessment of phytoremediation of petroleum contaminated soils

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Banks, M.K.; Schwab, A.P.; Wang, X.

    Phytoremediation of soils contaminated with petroleum and associated priority pollutants was evaluated in greenhouse and laboratory experiments. Mineralization of several PAHs was measured in rhizosphere soil, non-rhizosphere soil, and sterile soil amended with simulated root exudates. The least amount of mineralization was observed in sterile soil, but there were no differences among all other soils. Mineralization of 14 C-benzo[a]pyrene was determined in chambers to determine the effects of tall fescue on dissipation of this compound. After 180 days, the soils with fescue had more than twice the mineralization than soils without plants. In the soils with plants, evolution of 14CO2more » from the soil was five times greater than from the plant biomass. These experiments demonstrate that the presence of plants is a necessary part of the phytoremediation process. There appears to be no residual rhizosphere effect, and the simple exudation of organic compounds does not mimic fully the presence of roots.« less

  19. Methodology for setting risk-based concentrations of contaminants in soil and groundwater and application to a model contaminated site.

    PubMed

    Fujinaga, Aiichiro; Uchiyama, Iwao; Morisawa, Shinsuke; Yoneda, Minoru; Sasamoto, Yuzuru

    2012-01-01

    In Japan, environmental standards for contaminants in groundwater and in leachate from soil are set with the assumption that they are used for drinking water over a human lifetime. Where there is neither a well nor groundwater used for drinking, the standard is thus too severe. Therefore, remediation based on these standards incurs excessive effort and cost. In contrast, the environmental-assessment procedure used in the United States and the Netherlands considers the site conditions (land use, existing wells, etc.); however, a risk assessment is required for each site. Therefore, this study proposes a new framework for judging contamination in Japan by considering the merits of the environmental standards used and a method for risk assessment. The framework involves setting risk-based concentrations that are attainable remediation goals for contaminants in soil and groundwater. The framework was then applied to a model contaminated site for risk management, and the results are discussed regarding the effectiveness and applicability of the new methodology. © 2011 Society for Risk Analysis.

  20. Importance of organic amendment characteristics on bioremediation of PAH-contaminated soil.

    PubMed

    Lukić, B; Huguenot, D; Panico, A; Fabbricino, M; van Hullebusch, E D; Esposito, G

    2016-08-01

    This study investigates the importance of the organic matter characteristics of several organic amendments (i.e., buffalo manure, food and kitchen waste, fruit and vegetables waste, and activated sewage sludge) and their influence in the bioremediation of a polycyclic aromatic hydrocarbons (PAH)-contaminated soil. The removal of low molecular weights (LMW) and high molecular weights (HMW) PAHs was monitored in four bioremediation reactors and used as an indicator of the role of organic amendments in contaminant removal. The total initial concentration of LMW PAHs was 234 mg kg(-1) soil (dry weight), while the amount for HMW PAHs was 422 mg kg(-1) soil (dry weight). Monitoring of operational parameters and chemical analysis was performed during 20 weeks. The concentrations of LMW PAH residues in soil were significantly lower in reactors that displayed a mesophilic phase, i.e., 11 and 15 %, compared to reactors that displayed a thermophilic phase, i.e., 29 and 31 %. Residual HMW PAHs were up to five times higher compared to residual LMW PAHs, depending on the reactor. This demonstrated that the amount of added organic matter and macronutrients such as nitrogen and phosphorus, the biochemical organic compound classes (mostly soluble fraction and proteins), and the operational temperature are important factors affecting the overall efficiency of bioremediation. On that basis, this study shows that characterization of biochemical families could contribute to a better understanding of the effects of organic amendments and clarify their different efficiency during a bioremediation process of PAH-contaminated soil.

  1. Strategies for sustainable woodland on contaminated soils.

    PubMed

    Dickinson, N M

    2000-07-01

    Extensive in situ reclamation treatment technologies are appropriate for a large proportion of contaminated land in place of total removal or complete containment of soil. In this paper, initial results are presented of site descriptions, tree survival and metal uptake patterns from two field planting trials on a highly industrially contaminated site adjacent to a metal refinery and on old sanitary landfill sites. Survival rate was high in both trials but factors besides heavy metals were particularly significant. Uptake patterns of metals into foliage and woody tissues were variable, with substantial uptake in some species and clones supporting the findings of earlier pot experiments. It is argued that there is sufficient evidence to consider the use of trees in reclamation as part of a realistic, integrated, low-cost, ecologically-sound and sustainable reclamation strategy for contaminated land. This is an opportunity to bring a large number of brownfield sites into productive use, which otherwise would be prohibitively expensive to restore.

  2. Effects of freeze-thaw on characteristics of new KMP binder stabilized Zn- and Pb-contaminated soils.

    PubMed

    Wei, Ming-Li; Du, Yan-Jun; Reddy, Krishna R; Wu, Hao-Liang

    2015-12-01

    For viable and sustainable reuse of solidified/stabilized heavy metal-contaminated soils as roadway subgrade materials, long-term durability of these soils should be ensured. A new binder, KMP, has been developed for solidifying/stabilizing soils contaminated with high concentrations of heavy metals. However, the effects of long-term extreme weather conditions including freeze and thaw on the leachability and strength of the KMP stabilized contaminated soils have not been investigated. This study presents a systematic investigation on the impacts of freeze-thaw cycle on leachability, strength, and microstructural characteristics of the KMP stabilized soils spiked with Zn and Pb individually and together. For comparison purpose, Portland cement is also tested as a conventional binder. Several series of tests are conducted including the toxicity characteristic leaching procedure (TCLP), modified European Community Bureau of Reference (BCR) sequential extraction procedure, unconfined compression test (UCT), and mercury intrusion porosimetry (MIP). The results demonstrate that the freeze-thaw cycles have much less impact on the leachability and strength of the KMP stabilized soils as compared to the PC stabilized soils. After the freeze-thaw cycle tests, the KMP stabilized soils display much lower leachability, mass loss, and strength loss. These results are assessed based on the chemical speciation of Zn and Pb, and pore size distribution of the soils. Overall, this study demonstrates that the KMP stabilized heavy metal-contaminated soils perform well under the freeze-thaw conditions.

  3. Evaluation of the effect of indigenous mycogenic silver nanoparticles on soil exo-enzymes in barite mine contaminated soils

    NASA Astrophysics Data System (ADS)

    Gaddam, Durga Prameela; Devamma, Nagalakshmi; Prasad, Tollamadugu Naga Venkata Krishna Vara

    2015-04-01

    The biosynthesis of nanoparticles has received increasing attention due to the growing need to develop safe, cost-effective and environmentally friendly technologies for nanoscale materials synthesis. In this report, silver nanoparticles (AgNPs) were synthesized by treating aqueous Ag+ ions with the culture supernatants of indigenous fungal species of Fusarium solani isolated from barite mine contaminated soils. The formation of AgNPs might be an enzyme-mediated extracellular reaction process. The localized surface plasmon resonance of the formed AgNPs was recorded using UV-VIS spectrophotometer and was characterized using the techniques transmission electron microscopy, particle size analyzer, Fourier transform-infrared spectroscopy (FT-IR), particle size (dynamic light scattering) and zeta potential. The synthesized AgNPs were stable, polydispersed with the average size of 80 nm. FT-IR spectra reveals that proteins and carboxylic groups present in the fungal secrets might be responsible for the reduction and stabilization of the silver ions. Applied to the barite mine contaminated soils, concentration of AgNPs and incubation period significantly influences the soil exo-enzymatic activities, viz., urease, phosphatase, dehydrogenase and β-glucosidase. To the best of our knowledge, this is the first report on this kind of work in barite mine contaminated soils.

  4. Dynamics And Remediation Of Fine Textured Soils And Ground Water Contaminated With Salts And Chlorinated Organic Compounds

    NASA Astrophysics Data System (ADS)

    Murata, Alison; Naeth, M. Anne

    2017-04-01

    Soil and ground water are frequently contaminated by industrial activities, posing a potential risk to human and environmental health and limiting land use. Proper site management and remediation treatments can return contaminated areas to safe and useful states. Most remediation research focuses on single contaminants in coarse and medium textured soils. Contaminant mixtures are common and make remediation efforts complex due to differing chemical properties. Remediation in fine textured soils is difficult since their low hydraulic conductivities hinder addition of amendments into and removal of contaminated media out of the impacted zone. The objective of this research is to assess contaminant dynamics and potential remediation techniques for fine textured soil and ground water impacted by multiple contaminants in Edmonton, Alberta, Canada. The University of Alberta's Ellerslie Waste Management Facility was used to process liquid laboratory waste from 1972 to 2007. A waste water pond leak prior to 1984 resulted in salt and chlorinated organic compound contamination. An extensive annual ground water monitoring data set for the site is available since 1988. Analytical parameters include pH, electrical conductivity, major ions, volatile organic compounds, and metals. Data have been compared to Alberta Tier 1 Soil and Groundwater Remediation Guidelines to identify exceedances. The parameters of greatest concern, based on magnitude and frequency of detection, are electrical conductivity, sodium, chloride, chloroform, and dichloromethane. Spatial analyses of the data show that the contamination is focused in and down gradient of the former waste water pond. Temporal analyses show different trends depending on monitoring well location. Laboratory column experiments were used to assess leaching as a potential treatment for salt contamination in fine textured soils. Saturated hydraulic conductivity was measured for seven soils from two depth intervals with or without

  5. Influence of indian mustard (Brassica juncea) on rhizosphere soil solution chemistry in long-term contaminated soils: a rhizobox study.

    PubMed

    Kim, Kwon-Rae; Owens, Gary; Kwon, Soon-lk

    2010-01-01

    This study investigated the influence of Indian mustard (Brassica juncea) root exudation on soil solution properties (pH, dissolved organic carbon (DOC), metal solubility) in the rhizosphere using a rhizobox. Measurement was conducted following the cultivation of Indian mustard in the rhizobox filled four different types of heavy metal contaminated soils (two alkaline soils and two acidic soils). The growth of Indian mustard resulted in a significant increase (by 0.6 pH units) in rhizosphere soil solution pH of acidic soils and only a slight increase (< 0.1 pH units) in alkaline soils. Furthermore, the DOC concentration increased by 17-156 mg/L in the rhizosphere regardless of soil type and the extent of contamination, demonstrating the exudation of DOC from root. Ion chromatographic determination showed a marked increase in the total dissolved organic acids (OAs) in rhizosphere. While root exudates were observed in all soils, the amount of DOC and OAs in soil solution varied considerably amongst different soils, resulting in significant changes to soil solution metals in the rhizosphere. For example, the soil solution Cd, Cu, Pb, and Zn concentrations increased in the rhizosphere of alkaline soils compared to bulk soil following plant cultivation. In contrast, the soluble concentrations of Cd, Pb, and Zn in acidic soils decreased in rhizosphere soil when compared to bulk soils. Besides the influence of pH and DOC on metal solubility, the increase of heavy metal concentration having high stability constant such as Cu and Pb resulted in a release of Cd and Zn from solid phase to liquid phase.

  6. Poplar response to cadmium and lead soil contamination.

    PubMed

    Radojčić Redovniković, Ivana; De Marco, Alessandra; Proietti, Chiara; Hanousek, Karla; Sedak, Marija; Bilandžić, Nina; Jakovljević, Tamara

    2017-10-01

    An outdoor pot experiment was designed to study the potential of poplar (Populus nigra 'Italica') in phytoremediation of cadmium (Cd) and lead (Pb). Poplar was treated with a combination of different concentrations of Cd (w = 10, 25, 50mgkg -1 soil) and Pb (400, 800, 1200mgkg -1 soil) and several physiological and biochemical parameters were monitored including the accumulation and distribution of metals in different plant parts (leaf, stem, root). Simultaneously, the changes in the antioxidant system in roots and leaves were monitored to be able to follow synergistic effects of both heavy metals. Moreover, a statistical analysis based on the Random Forests Analysis (RFA) was performed in order to determine the most important predictors affecting growth and antioxidative machinery activities of poplar under heavy metal stress. The study demonstrated that tested poplar could be a good candidate for phytoextraction processes of Cd in moderately contaminated soils, while in heavily contaminated soil it could be only considered as a phytostabilisator. For Pb remediation only phytostabilisation process could be considered. By using RFA we pointed out that it is important to conduct the experiments in an outdoor space and include environmental conditions in order to study more realistic changes of growth parameters and accumulation and distribution of heavy metals. Also, to be able to better understand the interactions among previously mentioned parameters, it is important to conduct the experiments during prolonged time exposure., This is especially important for the long life cycle woody species. Copyright © 2017. Published by Elsevier Inc.

  7. Effect of soil properties, heavy metals and emerging contaminants in the soil nematodes diversity.

    PubMed

    Gutiérrez, Carmen; Fernández, Carlos; Escuer, Miguel; Campos-Herrera, Raquel; Beltrán Rodríguez, Mª Eulalia; Carbonell, Gregoria; Rodríguez Martín, Jose Antonio

    2016-06-01

    Among soil organisms, nematodes are seen as the most promising candidates for bioindications of soil health. We hypothesized that the soil nematode community structure would differ in three land use areas (agricultural, forest and industrial soils), be modulated by soil parameters (N, P, K, pH, SOM, CaCO3, granulometric fraction, etc.), and strongly affected by high levels of heavy metals (Cd, Pb, Zn, Cr, Ni, Cu, and Hg) and emerging contaminants (pharmaceuticals and personal care products, PPCPs). Although these pollutants did not significantly affect the total number of free-living nematodes, diversity and structure community indices vastly altered. Our data showed that whereas nematodes with r-strategy were tolerant, genera with k-strategy were negatively affected by the selected pollutants. These effects diminished in soils with high levels of heavy metals given their adaptation to the historical pollution in this area, but not to emerging pollutants like PPCPs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. The validation of forensic DNA extraction systems to utilize soil contaminated biological evidence.

    PubMed

    Kasu, Mohaimin; Shires, Karen

    2015-07-01

    The production of full DNA profiles from biological evidence found in soil has a high failure rate due largely to the inhibitory substance humic acid (HA). Abundant in various natural soils, HA co-extracts with DNA during extraction and inhibits DNA profiling by binding to the molecular components of the genotyping assay. To successfully utilize traces of soil contaminated evidence, such as that found at many murder and rape crime scenes in South Africa, a reliable HA removal extraction system would often be selected based on previous validation studies. However, for many standard forensic DNA extraction systems, peer-reviewed publications detailing the efficacy on soil evidence is either lacking or is incomplete. Consequently, these sample types are often not collected or fail to yield suitable DNA material due to the use of unsuitable methodology. The aim of this study was to validate the common forensic DNA collection and extraction systems used in South Africa, namely DNA IQ, FTA elute and Nucleosave for processing blood and saliva contaminated with HA. A forensic appropriate volume of biological evidence was spiked with HA (0, 0.5, 1.5 and 2.5 mg/ml) and processed through each extraction protocol for the evaluation of HA removal using QPCR and STR-genotyping. The DNA IQ magnetic bead system effectively removed HA from highly contaminated blood and saliva, and generated consistently acceptable STR profiles from both artificially spiked samples and crude soil samples. This system is highly recommended for use on soil-contaminated evidence over the cellulose card-based systems currently being preferentially used for DNA sample collection. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  9. Comparison of commercial DNA extraction kits for isolation and purification of bacterial and eukaryotic DNA from PAH-contaminated soils.

    PubMed

    Mahmoudi, Nagissa; Slater, Greg F; Fulthorpe, Roberta R

    2011-08-01

    Molecular characterization of the microbial populations of soils and sediments contaminated with polycyclic aromatic hydrocarbons (PAHs) is often a first step in assessing intrinsic biodegradation potential. However, soils are problematic for molecular analysis owing to the presence of organic matter, such as humic acids. Furthermore, the presence of contaminants, such as PAHs, can cause further challenges to DNA extraction, quantification, and amplification. The goal of our study was to compare the effectiveness of four commercial soil DNA extraction kits (UltraClean Soil DNA Isolation kit, PowerSoil DNA Isolation kit, PowerMax Soil DNA Isolation kit, and FastDNA SPIN kit) to extract pure, high-quality bacterial and eukaryotic DNA from PAH-contaminated soils. Six different contaminated soils were used to determine if there were any biases among the kits due to soil properties or level of contamination. Extracted DNA was used as a template for bacterial 16S rDNA and eukaryotic 18S rDNA amplifications, and PCR products were subsequently analyzed using denaturing gel gradient electrophoresis (DGGE). We found that the FastDNA SPIN kit provided significantly higher DNA yields for all soils; however, it also resulted in the highest levels of humic acid contamination. Soil texture and organic carbon content of the soil did not affect the DNA yield of any kit. Moreover, a liquid-liquid extraction of the DNA extracts found no residual PAHs, indicating that all kits were effective at removing contaminants in the extraction process. Although the PowerSoil DNA Isolation kit gave relatively low DNA yields, it provided the highest quality DNA based on successful amplification of both bacterial and eukaryotic DNA for all six soils. DGGE fingerprints among the kits were dramatically different for both bacterial and eukaryotic DNA. The PowerSoil DNA Isolation kit revealed multiple bands for each soil and provided the most consistent DGGE profiles among replicates for both

  10. POTENTIAL REUSE OF PETROLEUM-CONTAMINATED SOIL: A DIRECTOR OF PERMITTED RECYCLING FACILITIES

    EPA Science Inventory

    Soil contaminated by virgin petroleum products leaking from underground storage tanks is a pervasive problem In the United States. conomically feasible disposal of such soil concerns the responsible party (RP), whether the RP Ia one individual small business owner a group of owne...

  11. POTENTIAL REUSE OF PETROLEUM-CONTAMINATED SOIL: A DIRECTORY OF PERMITTED RECYCLING FACILITIES

    EPA Science Inventory

    Soil contaminated by virgin petroleum products leaking from underground storage tanks Is a pervasive problem in the United States. Economically feasible disposal of such soil concerns the responsible party (RP), whether the RP is one individual small business owner, a group o...

  12. MANAGING ARSENIC CONTAMINATED SOIL, SEDIMENT, AND INDUSTRIAL WASTE WITH SOLIDIFICATION/STABILIZATION TREATMENT

    EPA Science Inventory

    Arsenic contamination of soil, sediment and groundwater is a widespread problem in certain areas and has caused great public concern due to increased awareness of the health risks. Often the contamination is naturally occurring, but it can also be a result of waste generated from...

  13. Enhancing Bioremediation of Oil-contaminated Soils by Controlling Nutrient Transport using Dual Characteristics of Soil Pore Structure

    NASA Astrophysics Data System (ADS)

    Mori, Y.; Suetsugu, A.; Matsumoto, Y.; Fujihara, A.; Suyama, K.; Miyamoto, T.

    2012-12-01

    Soil structure is heterogeneous with cracks or macropores allowing bypass flow, which may lead to applied chemicals avoiding interaction with soil particles or the contaminated area. We investigated the bioremediation efficiency of oil-contaminated soils by applying suction at the bottom of soil columns during bioremediation. Unsaturated flow conditions were investigated so as to avoid bypass flow and achieve sufficient dispersion of chemicals in the soil column. The boundary conditions at the bottom of the soil columns were 0 kPa and -3 kPa, and were applied to a volcanic ash soil with and without macropores. Unsaturated flow was achieved with -3 kPa and an injection rate of 1/10 of the saturated hydraulic conductivity. The resultant biological activities of the effluent increased dramatically in the unsaturated flow with macropores condition. Unsaturated conditions prevented bypass flow and allowed dispersion of the injected nutrients. Unsaturated flow achieved 60-80% of saturation, which enhanced biological activity in the soil column. Remediation results were better for unsaturated conditions because of higher biological activity. Moreover, unsaturated flow with macropores achieved uniform remediation efficiency from upper through lower positions in the column. Finally, taking the applied solution volume into consideration, unsaturated flow with -3 kPa achieved 10 times higher efficiency when compared with conventional saturated flow application. These results suggest that effective use of nutrients or remediation chemicals is possible by avoiding bypass flow and enhancing biological activity using relatively simple and inexpensive techniques.

  14. Effect of biosludge and biofertilizer amendment on growth of Jatropha curcas in heavy metal contaminated soils.

    PubMed

    Juwarkar, Asha Ashok; Yadav, Santosh Kumar; Kumar, Phani; Singh, Sanjeev Kumar

    2008-10-01

    The pot experiments were conducted to evaluate the effect of different concentrations of arsenic, chromium and zinc contaminated soils, amended with biosludge and biofertilizer on the growth of Jatropha curcas which is a biodiesel crop. The results further showed that biosludge alone and in combination with biofertilizer significantly improved the survival rates and enhanced the growth of the plant. With the amendments, the plant was able to grow and survive upto 500, 250 and 4,000 mg kg(-1) of As, Cr and Zn contaminated soils, respectively. The results also showed that zinc enhanced the growth of J. curcas more as compared to other metals contaminated soils. The heavy metal accumulation in plant increased with increasing concentrations of heavy metals in soil, where as a significant reduction in the metal uptake in plant was observed, when amended with biosludge and biofertilizer and biosludge alone. It seems that the organic matter present in the biosludge acted as metal chelator thereby reducing the toxicity of metals to the plant. Findings suggest that plantation of J. curcas may be promoted in metal contaminated soils, degraded soils or wasteland suitably after amending with organic waste.

  15. Toxicological benchmarks for screening potential contaminants of concern for effects on soil and litter invertebrates and heterotrophic process

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Will, M.E.; Suter, G.W. II

    1994-09-01

    One of the initial stages in ecological risk assessments for hazardous waste sites is the screening of contaminants to determine which of them are worthy of further consideration as {open_quotes}contaminants of potential concern.{close_quotes} This process is termed {open_quotes}contaminant screening.{close_quotes} It is performed by comparing measured ambient concentrations of chemicals to benchmark concentrations. Currently, no standard benchmark concentrations exist for assessing contaminants in soil with respect to their toxicity to soil- and litter-dwelling invertebrates, including earthworms, other micro- and macroinvertebrates, or heterotrophic bacteria and fungi. This report presents a standard method for deriving benchmarks for this purpose, sets of data concerningmore » effects of chemicals in soil on invertebrates and soil microbial processes, and benchmarks for chemicals potentially associated with United States Department of Energy sites. In addition, literature describing the experiments from which data were drawn for benchmark derivation. Chemicals that are found in soil at concentrations exceeding both the benchmarks and the background concentration for the soil type should be considered contaminants of potential concern.« less

  16. USING PLANTS TO REMEDIATE PETROLEUM-CONTAMINATED SOIL: PROJECT CONTINUATION

    EPA Science Inventory

    Crude oil contamination of soil often occurs adjacent to wellheads and storage facilities. Phytoremediation is a promising tool that can be used to remediate such sites and uses plants and agronomic techniques to enhance biodegradation of hydrocarbons. This project has conduct...

  17. Human health risk assessment: A case study involving heavy metal soil contamination after the flooding of the river Meuse during the winter of 1993-1994.

    PubMed Central

    Albering, H J; van Leusen, S M; Moonen, E J; Hoogewerff, J A; Kleinjans, J C

    1999-01-01

    At the end of December 1993 and also at the end of January 1995, the river Meuse, one of the major rivers in Europe, flooded and river banks were inundated. We investigated the possible health risks of exposure to heavy metal concentrations in river bank soils resulting from the flooding of the river Meuse at the end of 1993. Soil and deposit samples and corresponding aerable and fodder crops were collected and analyzed for heavy metals. Although the soils of the floodplain of the river Meuse appeared severely polluted mainly by Cd and Zn, the heavy metal concentrations in the crops grown on these soils were within background ranges. Incidentally, the legal standard for Cd as endorsed by the Commodities Act was exceeded in wheat crops. The main exposure pathways for the general population were through the consumption of food crops grown on the river banks and through the direct ingestion of contaminated soils. For estimating potential human exposure in relation to soil pollution, we used a multiple pathway exposure model. For estimating the actual risk, we determined metal contents of vegetables grown in six experimental gardens. From this study, it can be concluded that there is a potential health risk for the river bank inhabitants as a consequence of Pb and Cd contaminations of the floodplain soils of the river Meuse, which are frequently inundated (averaged flooding frequency once every 2 years). Images Figure 1 Figure 2 PMID:9872715

  18. Reductive Dehalogenation of Organic Contaminants in Soils and Ground Water

    EPA Pesticide Factsheets

    Reductive dehalogenation is a process which may prove to be of paramount importance in dealing with a particularly persistent class of contaminants often found in soil and ground water at superfund sites.

  19. Soil-Water Repellency and Critical Humidity as Cleanup Criteria for Remediation of a Hydrocarbon Contaminated Mud

    NASA Astrophysics Data System (ADS)

    Guzmán, Francisco Javier; Adams, Randy H.

    2010-05-01

    , the FC dropped to 25,6% H, likely due to organic matter decomposition. However, during the following year+ (13½ months) the FC increased to 33,8%H probably due to an increase of soil humic substances while a vigorous vegetative growth was established. During two years of treatment the MED values were reduced 30% from 5,13 to 3,58M, and WDPT values were reduced over 25 times (from 10 exp5,6 s to 10 exp4,2 s). Critical humidity values varied from ~16,9 - 19,5%H for penetration in <5 s and from ~15,1 - 15,5%H for penetration in <60 s, in both treated and untreated material. During the driest part of the year, in May before the first rains, the soil humidity was 20,3%, and thus values below the critical levels were not experienced. This permitted the development of a complete vegetative cover, vigorous growth, and transformation of a geologic substrate (bentonitic drilling muds) into a soil-like material apt for agricultural use. This focus on soil-water relationships and the use of soil fertility parameters in general is important in establishing cleanup criteria for the real remediation of hydrocarbon contaminated sites in agricultural areas. As seen in this study, relatively high WDPT and MED values may not necessarily indicate soil moisture problems and these need to be complemented with actual site information on soil humidity during the annual cycle and with determinations of critical humidity. Additionally, the augmentation of field capacity using organic conditioners may effectively mitigate potential critical humidity problems.

  20. Do biochars influence the availability and human oral bioaccessibility of Cd, Pb, and Zn in a contaminated slightly alkaline soil?

    PubMed

    Janus, Adeline; Waterlot, Christophe; Heymans, Sophie; Deboffe, Christophe; Douay, Francis; Pelfrêne, Aurélie

    2018-03-14

    Different remediation techniques have been used to restore metal-contaminated sites, including stabilizing metals by adding amendments to the soils. This study experimented three biochars, made from wood and miscanthus, cultivated on contaminated and uncontaminated soils, used as amendments at a 2% application rate on a metal-contaminated soil for 9 months in laboratory-controlled conditions. The objective was to evaluate whether biochars were able to decrease the availability and human oral bioaccessibility of metals in an alkaline soil. To meet this goal, the modifications of the soil's physicochemical parameters, metal distribution in soil, and human bioaccessibility were evaluated at different sampling times. The results showed that biochar application to the alkaline soil did not always decrease the soil metal availability, which challenges the value of using biochars in already slightly alkaline soils at a low application rate. However, differences in efficiency between the three biochars tested were highlighted. The biochar produced with miscanthus cultivated on uncontaminated soil led to higher soil metal bioaccessibility. Moreover, because of the absence of any increase in soil metal availability with the biochar produced from biomass cultivated on contaminated soil, the use of such biochars can be recommended for the remediation of contaminated soil.