Sample records for relevant soil contaminations

  1. (Contaminated soil)

    SciTech Connect

    Siegrist, R.L.


    The traveler attended the Third International Conference on Contaminated Soil, held in Karlsruhe, Germany. The Conference was a status conference for worldwide research and practice in contaminated soil assessment and environmental restoration, with more than 1500 attendees representing over 26 countries. The traveler made an oral presentation and presented a poster. At the Federal Institute for Water, Soil and Air Hygiene, the traveler met with Dr. Z. Filip, Director and Professor, and Dr. R. Smed-Hildmann, Research Scientist. Detailed discussions were held regarding the results and conclusions of a collaborative experiment concerning humic substance formation in waste-amended soils.

  2. Assessing the ecotoxicological effects of long-term contaminated mine soils on plants and earthworms: relevance of soil (total and available) and body concentrations.


    García-Gómez, Concepción; Esteban, Elvira; Sánchez-Pardo, Beatriz; Fernández, María Dolores


    The interactions and relevance of the soil (total and available) concentrations, accumulation, and acute toxicity of several essential and non-essential trace elements were investigated to determine their importance in environmental soil assessment. Three plant species (T. aestivum, R. sativum, and V. sativa) and E. fetida were simultaneously exposed for 21 days to long-term contaminated soils collected from the surroundings of an abandoned pyrite mine. The soils presented different levels of As and metals, mainly Zn and Cu, and were tested at different soil concentrations [12.5, 25, 50, and 100% of contaminated soil/soil (w/w)] to increase the range of total and available soil concentrations necessary for the study. The total concentrations in the soils (of both As and metals) were better predictors of earthworm uptake than were the available concentrations. In plants, the accumulation of metals was related to the available concentrations of Zn and Cu, which could indicate that plants and earthworms accumulate elements from different pools of soil contaminants. Moreover, Zn and Cu, which are essential elements, showed controlled uptake at low concentrations. The external metal concentrations predicted earthworm mortality, whereas in plants, the effects on growth were correlated to the As and metal contents in the plants. In general, the bioaccumulation factors were lower at higher exposure levels, which implies the existence of auto-regulation in the uptake of both essential and non-essential elements by plants and earthworms. PMID:24875255

  3. Relevance of Radiocaesium Interception Potential (RIP) on a worldwide scale to assess soil vulnerability to 137Cs contamination.


    Vandebroek, Louis; Van Hees, May; Delvaux, Bruno; Spaargaren, Otto; Thiry, Yves


    The extent of radiocaesium retention in soil is important to quantify the risk of further foodchain contamination. The Radiocaesium Interception Potential (RIP -Cremers et al., 1988, Nature 335, 247-249) is an intrinsic soil parameter which can be used to categorize soils or minerals in terms of their capacity to selectively adsorb radiocaesium. In this study, we measured RIP for a large soil collection (88 soil samples) representative of major FAO soil reference groups on a worldwide scale and tested the possibility to predict the RIP on the basis of other easily accessible or measurable soil data. We also compared RIP values with those obtained from separate chemical extraction experiments. The range of measured RIP values (1.8-13300 mmol kg(-1)) was shown to include nearly all possible cases of agricultural soil contamination. Only Podzols, Andosols and Ferralsols were clearly characterized by a very low RIP (<2000 mmol kg(-1)). On a worldwide scale, RIP was in fact slightly related to soil reference type or other simple major physicochemical parameters such as clay percentage or organic matter. Conversely our results indicated a link between the RIP and radiocaesium extractability across very different soils. We showed that, with the proposed scale of RIP values, a simple acid extraction method can provide an operational result highly predictive of potential RIP despite very contrasting soil properties. The RIP could be estimated from the empirical equation: RIP = (-31.701 ∗ log(AER) + 58.886)(2) where AER is the fraction of acid-extractable radiocaesium. PMID:21963466

  4. Evaluating soil contamination

    SciTech Connect

    Beyer, W.


    The 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. 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.

  5. Remediating munitions contaminated soils

    SciTech Connect

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


    The former Nebraska Ordnance Plant (NOP) at Mead, NE was a military loading, assembling, and packing facility that produced bombs, boosters and shells during World War II and the Korean War (1942-1945, 1950-1956). Ordnances were loaded with 2,4,6-trinitrotoluene (TNT), amatol (TNT and NH{sub 4}NO{sub 3}), tritonal (TNT and Al) and Composition B (hexahydro-1,3,5-trinitro-1,3,5-triazine [RDX] and TNT). Process waste waters were discharged into wash pits and drainage ditches. Soils within and surrounding these areas are contaminated with TNT, RDX and related compounds. A continuous core to 300 cm depth obtained from an NOP drainage ditch revealed high concentrations of TNT in the soil profile and substantial amounts of monoamino reduction products, 4-amino-2,6-dinitrotoluene (4ADNT) and 2-amino-4,6-dinitrotoluene (2ADNT). Surface soil contained TNT in excess of 5000 mg kg{sup -1} and is believed to contain solid phase TNT. This is supported by measuring soil solution concentrations at various soil to solution ratios (1:2 to 1:9) and obtaining similar TNT concentrations (43 and 80 mg L{sup -1}). Remediating munitions-contaminated soil at the NOP and elsewhere is of vital interest since many of the contaminants are carcinogenic, mutagenic or otherwise toxic to humans and the environment. Incineration, the most demonstrated remediation technology for munitions-containing soils, is costly and often unacceptable to the public. Chemical and biological remediation offer potentially cost-effective and more environmentally acceptable alternatives. Our research objectives are to: (a) characterize the processes affecting the transport and fate of munitions in highly contaminated soil; (b) identify effective chemical and biological treatments to degrade and detoxify residues; and (c) integrate these approaches for effective and practical remediation of soil contaminated with TNT, RDX, and other munitions residues.

  6. Remediation of contaminated soils

    SciTech Connect

    Radhakrishnan, R.; Ariza, C.H.


    At least three types of zones of contamination exist whenever there is a chemical release. The impact of Non-Aqueous-Phase Liquids (NAPL) on soils and groundwater, together with the ultimate transport and migration of constituent chemicals in their dissolved or sorbed states, had led environmentalists to develop several techniques for cleaning a contaminated soil. Zone 1 represents the unsaturated zone which could be contaminated to retention capacity by both Dense Non-Aqueous-Phase Liquids (DNAPL) and Light Non-Aqueous-Phase Liquids (LNAPL). Zone 2 represents residual DNAPL or LNAPL contamination found below the groundwater table in the saturated zone. Zone 3 is represented by either the presence of NAPL dissolved in the aqueous phase, volatilized in the unsaturated zone or sorbed to either saturated or unsaturated soils. Cleanup of petroleum contaminated soils is presented in this paper. Among several techniques developed for this purpose, in-situ biological remediation is discussed in detail as a technique that does not involve excavation, thus, the costs and disruption of excavating soil are eliminated.

  7. Contaminated soil stabilization demonstration

    SciTech Connect

    Kemp, C.J.; Sackschewsky, M.R.; Sampson, A.E.; Phillips, S.J.


    Long-term herbicide control along with a shotcrete cover was constructed at the Hanford Site in May 1991. The cover system allows for maintenance-free containment of contaminants by preventing wind and water transport of contaminants from the soil surface, preventing plant uptake of contaminants, and minimizing water infiltration through the soil column. The cover is composed of two parts: a commercial nonwoven geotextile material impregnated with trifluralin, and a >5-centimeter top cover of shotcrete containing polyethylene fibers. The herbicide-impregnated geotextile functions to prevent plant root growth into contaminated soil if any holes or cracks develop in the shotcrete layer. The herbicide component, trifluralin, is mixed into polymer nodules that degrade slowly over many years, thus releasing trifluralin slowly over time. The shotcrete topcover was sprayed using a sludge pump and air compressor to form a hard, impenetrable surface that prevents wind erosion and reduces water infiltration through the contaminated materials underneath. The benefits of the cover system are expected to last 20 to 30 years. 2 refs., 4 figs.

  8. The relevance of speciation in the remediation of soils and sediments contaminated by metallic elements--an overview and examples from Central Scotland, UK.


    Hursthouse, A S


    The environmental impact of metallic contaminants in soils and sediments is dependent both on the chemical speciation of the metal and the response of the matrix to biological and physicochemical conditions. These factors are responsible for the mobilisation of the metal from the solid into the aquatic phase and hence transport within the immediate vicinity, impacting on the rate of dispersal, dilution, uptake and transfer into living systems. The impact of changing environmental conditions on the contaminant inventory can be to enhance or moderate these phenomena, with subsequent consequences for the broader risk assessment of the contaminants. Remediation of metallic contaminants can only be brought about by their removal from the site or by establishing conditions which favour their retention in the solid phase. A wide range of in situ and ex situ approaches are available and a summary overview is presented. The examples show assessment at both the field and laboratory scale and demonstrate an equally wide range of success in achieving remediation targets. This can be attributed to limitations in ensuring that the desired conditions for the initial removal or immobilisation process are met and maintained over a suitable period of time. Three areas are reviewed which include: the transport and release of metallic contaminants in estuarine sediments and the assessment of their potential to impact on biota; terrestrial contamination systems involving the release of chromium from waste ore contaminating urban environments; the response of metal-contaminated wastes to changing environmental conditions and the impact of natural bioremediation. The focus of the discussion is to highlight the generation of reliable speciation information and the problems associated with impact and risk assessment. Particular issues of concern are the laboratory to field scale evaluation of contaminant behaviour and the approach used to assess the reliability of remediation options. In


    SciTech Connect

    Durham, L.A.; Johnson, R.L.; Rieman, C.; Kenna, T.; Pilon, R.


    The U.S. Army Corps of Engineers (USACE) is conducting a cleanup of radiologically contaminated properties under the Formerly Utilized Sites Remedial Action Program (FUSRAP). The largest cost element for most of the FUSRAP sites is the transportation and disposal of contaminated soil. Project managers and engineers need an estimate of the volume of contaminated soil to determine project costs and schedule. Once excavation activities begin and additional remedial action data are collected, the actual quantity of contaminated soil often deviates from the original estimate, resulting in cost and schedule impacts to the project. The project costs and schedule need to be frequently updated by tracking the actual quantities of excavated soil and contaminated soil remaining during the life of a remedial action project. A soil volume estimate tracking methodology was developed to provide a mechanism for project managers and engineers to create better project controls of costs and schedule. For the FUSRAP Linde site, an estimate of the initial volume of in situ soil above the specified cleanup guidelines was calculated on the basis of discrete soil sample data and other relevant data using indicator geostatistical techniques combined with Bayesian analysis. During the remedial action, updated volume estimates of remaining in situ soils requiring excavation were calculated on a periodic basis. In addition to taking into account the volume of soil that had been excavated, the updated volume estimates incorporated both new gamma walkover surveys and discrete sample data collected as part of the remedial action. A civil survey company provided periodic estimates of actual in situ excavated soil volumes. By using the results from the civil survey of actual in situ volumes excavated and the updated estimate of the remaining volume of contaminated soil requiring excavation, the USACE Buffalo District was able to forecast and update project costs and schedule. The soil volume


    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...

  11. Biotreatment of explosive contaminated soils

    SciTech Connect

    Shen, C.F.; Guiot, S.R.; Manuel, M.F.


    The aim of this research was to develop a process which can be employed to remediate 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) contaminated soils. The TNT and RDX degrading ability of microorganisms in municipal activated sludge and anaerobic sludge was evaluated, along with the toxicity of TNT and RDX to the microorganisms under aerobic and anaerobic conditions. Biotreatment of TNT and RDX contaminated soils was studied in bioslurry reactors. Microcosm tests were also conducted to see if TNT and RDX removal from the slurry reactor is attributed to a mineralization to CO{sub 2}, and to determine the synergetic or antagonistic effct (if any) of TNT and RDX on the mineralization. Both sludge types were found to be rich sources of RDX degrading organisms. The supplement of anaerobic sludge in bioslurry reactor enhances the biodegradation of TNT and RDX, and leads to complete removal of TNT and RDX from the contaminated soil. Bioslurry reactors may be a cost-effective approach to the on-site bioremediation of soils contaminated with high levels of epxlosives.

  12. Testing contaminated soil

    SciTech Connect

    McKenna, J.; Pickering, E.


    Today`s environmental projects involve a variety of complex issues that property owners and environmental professionals have to consider before they embark on a site-remediation program. One of the key things that has to be done during a project is to understand and select the chemical analysis parameters (CAPs) that are needed to characterize the soil. For instance, site investigations to determine if a soil is polluted require engineers to carefully select CAPs that will yield this information. Offsite fusibilities that specialize in waste treatment and disposal, on the other hand, require CAPs that may vary greatly from the CAPs needed for site investigations. However, when offsite treatment and disposal is the preferred remedial option, one can save money and add value to a project by including the CAPs required by a treatment, storage and disposal (TSD) facility to those CAPs selected for the site investigation. To select the right combination of CAPs to cover both site investigations and treatment and disposal requires a clear understanding of the analytical methods underlying the CAPs. The following set of CAPs are typically required by RCRA and non-RCRA TSD facilities: Total petroleum hydrocarbons; EPA method 9045 for corrosivities (pH); Reactivity; Total RCRA-8 metals; EPA Method 8240 for volatile organic compounds; EPA Method 8270 for semi-volatile organic compounds (SVOCs); EPA Method 8080 for polychlorinated biphenyls (PCBs); EPA Method 1010 for ignitability. These are all described.

  13. Contaminant resorption during soil washing

    SciTech Connect

    Gombert, D.


    To evaluate the applicability of soil washing to a specific site requires some basic research in how contaminants are bound. Much can be learned from sequential extraction methodology based on micronutrient bioavailability studies wherein the soil matrix is chemically dissected to selectively remove particular fixation mechanisms independently. This procedure uses a series of progressively more aggressive solvents to dissolve the principle phases that make up a soil, however, the published studies do not appear to consider the potential for a contaminant released from one type of site to resorb on another site during an extraction. This physical model assumes no ion exchange or adsorption at sites either previously occupied by other ions, or exposed by the dissolution. Therefore, to make engineering use of the sequential extraction data, the release of contamination must be evaluated relative to the effects of resorption. Time release studies were conducted to determine the optimum duration for extraction to maximize complete destruction of the target matrix fraction while minimizing contaminant resorption. Tests with and without a potassium brine present to inhibit cesium resorption indicated extraction efficiency could be enhanced by as much as a factor of ten using the brine.

  14. Phytoremediation of Metal-Contaminated Soils

    SciTech Connect

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


    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 experiments 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.

  15. [Heterogeneity of parasitic contamination of megalopolis soils].


    Aliautdinova, L V; Semenova, T A; Zavoĭkin, V D


    A morphological group ofwhipworm (Trichuris trichiura) eggs, which is detectable in the soil samples from the city's different control lands, shows that their origin is heterogeneous and it is possible to differentiate them by morphometric signs. At the same time is necessary to consider the specific biological factors contributing to soil contamination. Priority in parasitic soil contamination should be given to animals, dogs in particular, which is supported by the fact that the dog walking grounds exhibit the highest contamination rates. PMID:21797059

  16. Phytoremediation of Soils Contaminated by Chlorinnated Hydrocarbons

    NASA Astrophysics Data System (ADS)

    Cho, C.; Sung, K.; Corapcioglu, M.


    In recent years, the possible use of deep rooted plants for phytoremediation of soil contaminants has been offered as a potential alternative for waste management, particularly for in situ remediation of large volumes of contaminated soils. Major objectives of this study are to evaluate the effectiveness of a warm season grass (Eastern Gamagrass) and a cool season prairie grass (Annual Ryegrass) in the phytoremediation of the soil contaminated with volatile organic compounds e.g., trichloroethylene (TCE), tetrachloroethylene (PCE), and 1,1,1-trichloroethane (TCA) and to determine the main mechanisms of target contaminant dissipation. The preliminary tests and laboratory scale tests were conducted to identify the main mechanisms for phytoremediation of the target contaminants, and to apply the technique in green house application under field conditions. The results of microcosm and bioreactor experiments showed that volatilization can be the dominant pathway of the target contaminant mass losses in soils. Toxicity tests, conducted in nutrient solution in the growth room, and in the greenhouse, showed that both Eastern gamagrass and Annual ryegrass could grow without harmful effects at up to 400 ppm each of all three contaminants together. Preliminary greenhouse experimentw were conducted with the 1.5 m long and 0.3 m diameter PVC columns. Soil gas concentrations monitored and microbial biomass in bulk and rhizosphere soil, root properties, and contaminant concentration in soil after 100 days were analyzed. The results showed that the soil gas concentration of contaminants has rapidly decreased especially in the upper soil and the contaminant concentraitons in soil were also significantly decreased to 0.024, 0.228, and 0.002 of C/Co for TCE, PCE and TCA, respectively. Significant plant effects were not found however showed contaminant loss through volatilization and plant contamination by air.


    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...

  18. Surfactants treatment of crude oil contaminated soils.


    Urum, Kingsley; Pekdemir, Turgay; Copur, Mehmet


    This study reports experimental measurements investigating the ability of a biological (rhamnolipid) and a synthetic (sodium dodecyl sulfate, SDS) surfactant to remove the North Sea Ekofisk crude oil from various soils with different particle size fractions under varying washing conditions. The washing parameters and ranges tested were as follows: temperature (5 to 50 degrees C), time (5 to 20 min), shaking speed (80 to 200 strokes/min), volume (5 to 20 cm3), and surfactant concentration (0.004 to 5 mass%). The contaminated soils were prepared in the laboratory by mixing crude oil and soils using a rotating cylindrical mixer. Two contamination cases were considered: (1) weathered contamination was simulated by keeping freshly contaminated soils in a fan assisted oven at 50 degrees C for 14 days, mimicking the weathering effect in a natural hot environment, and (2) nonweathered contamination which was not subjected to the oven treatment. The surfactants were found to have considerable potential in removing crude oil from different contaminated soils and the results were comparable with those reported in literature for petroleum hydrocarbons. The removal of crude oil with either rhamnolipid or SDS was within the repeatability range of +/-6%. The most influential parameters on oil removal were surfactant concentration and washing temperature. The soil cation exchange capacity and pH also influenced the removal of crude oil from the individual soils. However, due to the binding of crude oil to soil during weathering, low crude oil removal was achieved with the weathered contaminated soil samples. PMID:15271574

  19. In situ removal of contamination from soil


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


    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.

  20. In situ removal of contamination from soil


    Lindgren, Eric R.; Brady, Patrick V.


    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.

  1. Bioremediation of PAH contaminated soil samples

    SciTech Connect

    Joshi, M.M.; Lee, S.


    Soils contaminated with polynuclear aromatic hydrocarbons (PAHs) pose a hazard to life. The remediation of such sites can be done using physical, chemical, and biological treatment methods or a combination of them. It is of interest to study the decontamination of soil using bioremediation. The experiments were conducted using Acinetobacter (ATCC 31012) at room temperature without pH or temperature control. In the first series of experiments, contaminated soil samples obtained from Alberta Research Council were analyzed to determine the toxic contaminant and their composition in the soil. These samples were then treated using aerobic fermentation and removal efficiency for each contaminant was determined. In the second series of experiments, a single contaminant was used to prepare a synthetic soil sample. This sample of known composition was then treated using aerobic fermentation in continuously stirred flasks. In one set of flasks, contaminant was the only carbon source and in the other set, starch was an additional carbon source. In the third series of experiments, the synthetic contaminated soil sample was treated in continuously stirred flasks in the first set and in fixed bed in the second set and the removal efficiencies were compared. The removal efficiencies obtained indicated the extent of biodegradation for various contaminants, the effect of additional carbon source, and performance in fixed bed without external aeration.

  2. Uranium-contaminated soil pilot treatment study

    SciTech Connect

    Turney, W.R.J.R.; Mason, C.F.V.; Michelotti, R.A.


    A pilot treatment study is proving to be effective for the remediation of uranium-contaminated soil from a site at the Los Alamos National Laboratory by use of a two-step, zero-discharge, 100% recycle system. Candidate uranium-contaminated soils were characterized for uranium content, uranium speciation, organic content, size fractionization, and pH. Geochemical computer codes were used to forecast possible uranium leach scenarios. Uranium contamination was not homogenous throughout the soil. In the first step, following excavation, the soil was sorted by use of the ThemoNuclean Services segmented gate system. Following the sorting, uranium-contaminated soil was remediated in a containerized vat leach process by use of sodium-bicarbonate leach solution. Leach solution containing uranium-carbonate complexes is to be treated by use of ion-exchange media and then recycled. Following the treatment process the ion exchange media will be disposed of in an approved low-level radioactive landfill. It is anticipated that treated soils will meet Department of Energy site closure guidelines, and will be given {open_quotes}no further action{close_quotes} status. Treated soils are to be returned to the excavation site. A volume reduction of contaminated soils will successfully be achieved by the treatment process. Cost of the treatment (per cubic meter) is comparable or less than other current popular methods of uranium-contamination remediation.

  3. A petroleum contaminated soil bioremediation facility

    SciTech Connect

    Lombard, K.; Hazen, T.


    The amount of petroleum contaminated soil (PCS) at the Savannah River site (SRS) that has been identified, excavated and is currently in storage has increased several fold during the last few years. Several factors have contributed to this problem: (1) South Carolina Department of Health ad Environmental control (SCDHEC) lowered the sanitary landfill maximum concentration for total petroleum hydrocarbons (TPH) in the soil from 500 to 100 parts per million (ppm), (2) removal and replacement of underground storage tanks at several sites, (3) most recently SCDHEC disallowed aeration for treatment of contaminated soil, and (4) discovery of several very large contaminated areas of soil associated with leaking underground storage tanks (LUST), leaking pipes, disposal areas, and spills. Thus, SRS has an urgent need to remediate large quantities of contaminated soil that are currently stockpiled and the anticipated contaminated soils to be generated from accidental spills. As long as we utilize petroleum based compounds at the site, we will continue to generate contaminated soil that will require remediation.

  4. Soil Vapor Extraction of PCE/TCE Contaminated Soil

    SciTech Connect

    Bradley, J.M.; Morgenstern, M.R.


    The A/M Area of the Savannah River Site soil and groundwater is contaminated with tetrachloroethylene (PCE) and trichloroethylene (TCE). Contamination is the result of previous waste disposal practices, once considered state-of-the-art. Soil Vapor Extraction (SVE) units have been installed to remediate the A/M Area vadose zone. SVE is a proven in-situ method for removing volatile organics from a soil matrix with minimal site disturbance. SVE alleviates the infiltration of contaminants into the groundwater and reduces the total time required for groundwater remediation. Lessons learned and optimization of the SVE units are also discussed.

  5. Evidence of the generation of isosaccharinic acids and their subsequent degradation by local microbial consortia within hyper-alkaline contaminated soils, with relevance to intermediate level radioactive waste disposal.


    Rout, Simon P; Charles, Christopher J; Garratt, Eva J; Laws, Andrew P; Gunn, John; Humphreys, Paul N


    The contamination of surface environments with hydroxide rich wastes leads to the formation of high pH (>11.0) soil profiles. One such site is a legacy lime works at Harpur Hill, Derbyshire where soil profile indicated in-situ pH values up to pH 12. Soil and porewater profiles around the site indicated clear evidence of the presence of the α and β stereoisomers of isosaccharinic acid (ISA) resulting from the anoxic, alkaline degradation of cellulosic material. ISAs are of particular interest with regards to the disposal of cellulosic materials contained within the intermediate level waste (ILW) inventory of the United Kingdom, where they may influence radionuclide mobility via complexation events occurring within a geological disposal facility (GDF) concept. The mixing of uncontaminated soils with the alkaline leachate of the site resulted in ISA generation, where the rate of generation in-situ is likely to be dependent upon the prevailing temperature of the soil. Microbial consortia present in the uncontaminated soil were capable of surviving conditions imposed by the alkaline leachate and demonstrated the ability to utilise ISAs as a carbon source. Leachate-contaminated soil was sub-cultured in a cellulose degradation product driven microcosm operating at pH 11, the consortia present were capable of the degradation of ISAs and the generation of methane from the resultant H2/CO2 produced from fermentation processes. Following microbial community analysis, fermentation processes appear to be predominated by Clostridia from the genus Alkaliphilus sp, with methanogenesis being attributed to Methanobacterium and Methanomassiliicoccus sp. The study is the first to identify the generation of ISA within an anthropogenic environment and advocates the notion that microbial activity within an ILW-GDF is likely to influence the impact of ISAs upon radionuclide migration. PMID:25748643

  6. Evidence of the Generation of Isosaccharinic Acids and Their Subsequent Degradation by Local Microbial Consortia within Hyper-Alkaline Contaminated Soils, with Relevance to Intermediate Level Radioactive Waste Disposal

    PubMed Central

    Rout, Simon P.; Charles, Christopher J.; Garratt, Eva J.; Laws, Andrew P.; Gunn, John; Humphreys, Paul N.


    The contamination of surface environments with hydroxide rich wastes leads to the formation of high pH (>11.0) soil profiles. One such site is a legacy lime works at Harpur Hill, Derbyshire where soil profile indicated in-situ pH values up to pH 12. Soil and porewater profiles around the site indicated clear evidence of the presence of the α and β stereoisomers of isosaccharinic acid (ISA) resulting from the anoxic, alkaline degradation of cellulosic material. ISAs are of particular interest with regards to the disposal of cellulosic materials contained within the intermediate level waste (ILW) inventory of the United Kingdom, where they may influence radionuclide mobility via complexation events occurring within a geological disposal facility (GDF) concept. The mixing of uncontaminated soils with the alkaline leachate of the site resulted in ISA generation, where the rate of generation in-situ is likely to be dependent upon the prevailing temperature of the soil. Microbial consortia present in the uncontaminated soil were capable of surviving conditions imposed by the alkaline leachate and demonstrated the ability to utilise ISAs as a carbon source. Leachate-contaminated soil was sub-cultured in a cellulose degradation product driven microcosm operating at pH 11, the consortia present were capable of the degradation of ISAs and the generation of methane from the resultant H2/CO2 produced from fermentation processes. Following microbial community analysis, fermentation processes appear to be predominated by Clostridia from the genus Alkaliphilus sp, with methanogenesis being attributed to Methanobacterium and Methanomassiliicoccus sp. The study is the first to identify the generation of ISA within an anthropogenic environment and advocates the notion that microbial activity within an ILW-GDF is likely to influence the impact of ISAs upon radionuclide migration. PMID:25748643

  7. Bioremediation of uranium contaminated Fernald soils

    SciTech Connect

    Delwiche, M.E.; Wey, J.E.; Torma, A.E.


    This study investigated the use of microbial bioleaching for removal of uranium from contaminated soils. The ability of bacteria to assist in oxidation and solubilization of uranium was compared to the ability of fungi to produce complexing compounds which have the same effect. Biosorption of uranium by fungi was also measured. Soil samples were examined for changes in mineralogical properties due to these processes. On the basis of these laboratory scale studies a generalized flow sheet is proposed for bioremediation of contaminated Fernald soils.

  8. Soil contamination with radionuclides and potential remediation.


    Zhu, Y G; Shaw, G


    Soils contaminated with radionuclides, particularly 137Cs and 90Sr, pose a long-term radiation hazard to human health through exposure via the foodchain and other pathways. Remediation of radionuclide-contaminated soils has become increasingly important. Removal of the contaminated surface soil (often up to 40 cm) or immobilization of radionuclides in soils by applying mineral and chemical amendments are physically difficult and not likely cost-effective in practicality. Reducing plant uptake of radionuclides, especially 137CS and 90Sr by competitive cations contained in chemical fertilizers has the general advantage in large scale, low-level contamination incidents on arable land, and has been widely practiced in central and Western Europe after the Chernobyl accident. Phytoextraction of radionuclides by specific plant species from contaminated sites has rapidly stimulated interest among industrialists as well as academics, and is considered to be a promising bio-remediation method. This paper examines the existing remediation approaches and discusses phytoextraction of radionuclides from contaminated soils in detail. PMID:10819188


    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...

  10. Electrokinetic characterization techniques for contaminated soils

    SciTech Connect

    Eykholt, G.R.; Hung, H.


    One important element to the success of electrokinetic remediation of contaminated soils may be the assessment and control of the soil surface chemistry. This is usually reflected by an operative zeta-potential or electroosmotic coefficient, k{sub eo}, found by an electroosmosis test on a plug of contaminated soil. However, several researchers have shown that both the magnitude and uniformity of k{sub eo} change over the course of testing, as does the electric field intensity and zeta-potential, two basic parameters of the fundamental driving force. The electric field intensity can be measured during the test, but it is more difficult to assess the zeta potential. Independent techniques are needed. A conventional technique is dilute electrophoresis, but this test may not be truly representative or convenient. In this research summary, alternative techniques based on electroacoustic phenomena are presented in conjunction with other electrokinetic tests on reference and contaminated soils.

  11. Soil washing of fluorine contaminated soil using various washing solutions.


    Moon, Deok Hyun; Jo, Raehyun; Koutsospyros, Agamemnon; Cheong, Kyung Hoon; Park, Jeong-Hun


    Bench-scale soil washing experiments were conducted to remove fluoride from contaminated soils. Five washing solutions including hydrochloric acid (HCl), nitric acid (HNO3), sodium hydroxide (NaOH), sulfuric acid (H2SO4) and tartaric acid (C4H6O6) were tested. The concentration of the washing solutions used ranged from 0.1 to 3 M with a liquid to solid ratio of 10. The soil washing results showed that the most effective washing solution for the removal of fluoride from contaminated soils was HCl. The highest fluoride removal results of approximately 97 % from the contaminated soil were obtained using 3 M HCl. The fluoride removal efficiency of the washing solution increases in the following order: C4H6O6 < NaOH < H2SO4 < HNO3 < HCl. PMID:25552323

  12. Ecological Role of Soils upon Radioactive Contamination

    NASA Astrophysics Data System (ADS)

    Tsvetnov, Evgeny; Shcheglov, Alexei; Tsvenova, Olga


    The ecological role of soils upon radioactive contamination is clearly manifested in the system of notions about ecosystems services, i.e., benefits gained by humans from ecosystems and their components, including soils (Millennium Ecosystem Assessment, 2005). For the soils, these services are considered on the basis of soil functions in the biosphere that belong to the protective ecosystem functions within the group of soil functions known under the names of "Buffer and protective biogeocenotic shield" (at the level of particular biogeocenoses) and "Protective shield of the biosphere" (at the global biospheric level) (according to Dobrovol'skii & Nikitin, 2005). With respect to radionuclides, this group includes (1) the depositing function, i.e., the accumulation and long-term sequestration of radioactive substances by the soil after atmospheric fallout; (2) the geochemical function, i.e., the regulation of horizontal and vertical fluxes of radionuclides in the system of geochemically conjugated landscapes and in the soil-groundwater and soil-plant systems; and (3) the dose-forming function that is manifested by the shielding capacity of the soil with respect to the external ionizing radiation (lowering of the dose from external radiation) and by the regulation of the migration of radionuclides in the trophic chain (lowering of the dose from internal radiation). The depositing and geochemical functions of the soils are interrelated, which is seen from quantitative estimates of the dynamics of the fluxes of radionuclides in the considered systems (soil-plant, soil-groundwater, etc.). The downward migration of radionuclides into the lower soil layers proceeds very slowly: for decades, more than 90% of the pool of radionuclides is stored in the topmost 10 cm of the soil profile. In the first 3-5 years after the fallout, the downward migration of radionuclides with infiltrating water flows decreases from several percent to decimals and hundredths of percent from the

  13. 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


    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.

  14. Phytoremediation of soils contaminated by cadmium

    NASA Astrophysics Data System (ADS)

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


    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

  15. Soil contamination evaluations: Earthworms as indicators of soil quality

    SciTech Connect

    Linder, G.; Wilbom, D.


    Earthworms have frequently been evaluated in the field and laboratory as representatives of the soil community that are indicative of their habitat`s quality. Within a landscape or at a contaminated site, soil quality, or soil health, has become increasingly critical to cleanup-related issues that revolve around questions of ``how clean is clean`` and the bioaccumulation of soil contaminants. Through an overview of numerous field and laboratory studies, the role that earthworms have played in evaluating soil contamination will be reviewed with a particular focus on evaluations of the bioaccumulation potential of chemicals in soil. Within ecological contexts, earthworms can provide information regarding immediately observable adverse affects related, for example, to acute toxicity. Additionally, earthworms can provide information directly related to the bioaccumulation potential of a chemical and trophic transfer of environmental chemicals, especially through the food-chain. Within the decision-making process, soil contamination evaluations must consider future land-use, as well as current and future expressions of adverse biological and ecological effects under field conditions, potentially following remediation. Through integrated field and laboratory studies using earthworms, the authors have been able to identify adversely affected soil communities and have been able to provide information for assessing adverse ecological effects potentially caused by contaminants. Field surveys and on-site or in situ biological testing with earthworms, however, can not alone identify causes of effects. As such, standardized biological tests have been routinely completed in the laboratory so linkages between expression of effects and contaminants could be more readily addressed in conjunction with appropriate chemical data from the field.

  16. Incineration treatment of arsenic-contaminated soil

    SciTech Connect

    Waterland, L.R.; King, C.; Richards, M.K.; Thurnau, R.C.


    An incineration test program was conducted at the US 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 purpose of these tests was to evaluate the incinerability of these soils in terms of the fate of arsenic and lead and the destruction of organic contaminants during the incineration process. The test program consisted of a series of bench-scale experiments with a muffle furnace and a series of incineration tests in a pilot-scale rotary kiln incinerator system.

  17. Soil contamination standards for protection of personnel

    SciTech Connect

    Rittmann, P.D.


    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. External 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.

  18. Bioremediation of petroleum-contaminated soil

    SciTech Connect

    Pearce, K.; Snyman, H.G.; Oellermann, R.A.; Gerber, A.


    A pilot-scale study was conducted to evaluate the application of land-farming techniques in bioremediating a soil highly contaminated with petroleum products. A commercial biosupplement, and one prepared with indigenous microorganisms from the contaminated soil, were tested. Application of either of the biosupplements, in addition to the control of pH, moisture, and oxygen levels, resulted in a 94% reduction of the initial total petroleum hydrocarbon concentration (TPHC) (32% mass/mass) over a 70-day period. Implementation of these findings at full scale to bioremediate highly weathered petroleum products showed an average reduction of 89% over 5.5 months. Target levels of 1,400 mg/kg soil were reached from an initial average TPHC concentration of 12,200 mg/kg soil.

  19. Chelant soil-washing technology for metal-contaminated soil.


    Voglar, David; Lestan, Domen


    We demonstrate here, in a pilot-scale experiment, the feasibility of ethylenediaminetetraacetate (EDTA)based washing technology for soils contaminated with potentially toxic metals. Acid precipitation coupled to initial alkaline toxic metal removal and an electrochemical advanced oxidation process were used for average recovery of 76 +/- 2% of EDTA per batch and total recycle of water in a closed process loop. No waste water was generated; solid wastes were efficiently bitumen-stabilized before disposal. The technology embodiment, using conventional process equipment, such as a mixer for soil extraction, screen for soil/gravel separation, filter chamber presses for soil/liquid and recycled EDTA separation and soil rinsing, continuous centrifuge separator for removal of precipitated metals and electrolytic cells for process water cleansing, removed up to 72%, 25% and 66% of Pb, Zn and Cd from garden soil contaminated with up to 6960, 3797 and 32.6 mg kg(-1) of Pb, Zn and Cd, respectively, in nine 60kg soil batches. Concentrations of Pb and Zn remaining in the remediated soil and bioaccessible from the simulated human intestinal phase soil were reduced by 97% and 96% and were brought under the level of determination for Cd. In the most cost-effective operation mode, the material and energy costs of remediation amounted to 50.5 Euros ton(-1) soil and the total cost to 299 Euros ton(-1). PMID:24701937

  20. Solid phase bioremediation of petroleum contaminated soils

    SciTech Connect

    Potter, C.D.


    Solid phase bioremediation of petroleum contaminated soil involves aerobic biodegradation in an above grade treatment bed. This treatment technology is proposed for remediating soils contaminated by petroleum from leaking underground fuel storage tanks at various sites at the Oak Ridge Y-12 Plant. The treatment technology uses bacteria to degrade the petroleum hydrocarbons. The environmentally safe end products of the biodegradation process are carbon dioxide and water. A large, relatively level area is required to construct the perimeter berms, place the liner, and spread the contaminated soil in a 1 to 2 foot thick layer. A porous media is placed on top of the liner for protection and for proper drainage of leachate. Water, nutrients, and microorganisms are introduced into the soil in the treatment bed using conventional agricultural spraying techniques. Oxygen is supplied to the soil by periodic tilling on an ``as needed`` basis. To prevent soil erosion and to minimize leachate production during precipitation events, the treatment bed is completely covered by a plastic film. The treatment process is expected to require 3 to 8 months after construction is completed.

  1. Thermal treatment of fuel-contaminated soil

    SciTech Connect

    Not Available


    A patent has been issued for the apparatus and method for Low Temperature Thermal Stripping (LT/sup 3/) of volatile organic compounds (VOCs) from soil. LT/sup 3/ is a hazardous waste thermal treatment system and is used to clean up fuel-contaminated soil from leaking underground storage tanks. Representing a significant breakthrough in the treatment of polluted soil, LT/sup 3/ is a unique mix of proven techniques combined in an innovative way to provide an efficient cost-effective treatment method.

  2. Evaluation of soil washing for radiologically contaminated soils

    SciTech Connect

    Gombert, D. II


    Soil washing has been applied internationally to decontaminate soils due to the widespread increase in environmental awareness manifested in the United States by promulgation of the Comprehensive Environmental Response, Compensation and Liability Act, yet we continue to lack understanding on why the technique works in one application and not in another. A soil washing process typically integrates a variety of modules, each designed to decontaminate the matrix by destroying a particular phase or segregating a particle size fraction in which the contaminants are concentrated. The more known about how the contaminants are fixed, the more likely the process will succeed. Much can be learned from bioavailability studies on heavy metals in soils. Sequential extraction experiments designed to destroy one fixation mechanism at a time can be used to determine how contaminants are bound. This knowledge provides a technical basis for designing a processing strategy to efficiently decontaminate soil while creating a minimum of secondary wastes. In this study, a soil from the Idaho National Engineering Laboratory was physically and chemically characterized, then sequentially extracted to determine if soil washing could be effectively used to remove cesium, cobalt and chromium.


    EPA Science Inventory

    An incineration test program was conducted at the US 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. he purp...


    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...


    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...


    EPA Science Inventory

    A pilot-scale study will be conducted to evaluate the bioremedial techniques of natural attenuation, sequenced anaerobic/aerobic treatment, and addition of a commercially available microbial amendment product for use in treating PCB contaminated soils at Air Force Base sites. Th...


    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...

  8. Remediation of Mercury Contaminated Soils at the Miramas Site - 12243

    SciTech Connect

    Potier, G.; Chambon, F.


    Beneficial 'new' use of the Miramas Site is the remediation objective for a former light isotope manufacturing facility. Remediation operations will remove contaminated soils and materials and deconstruct facilities. The remediation objective is faced with project challenges and regulatory requirements that dictate/influence the outcome. The operation consists of the remediation of approximately 100,000 cubic meters of soil and the decommissioning of facilities. The types and ranges of waste are the result of historical processing activities (chemical facilities, pyrotechnic components storage, mining component treatment and light isotope manufacturing activities). Mercury is the primary component of the waste, but metals and organic compounds are also possible waste components. A thermal desorption process is used to remove Mercury from the polluted soil while a biological treatment is considered to the organic nitrate compound removal. A focus is done on the technologies used to remediate the Mercury contaminated soil. After few months of operation, the first results confirm that the technology choices were relevant and the soil remediation project is a success. The first successful month of operation at an industrial scale demonstrate that the Thermal Desorption is an efficient and relevant process to remediate large quantity of mercury contaminated soils. The project is on cost and the mercury removal should be end by 2014. The scrubbing is a good way to limit the volume of material to be treated with the Thermal Desorption Unit. The biological treatment is a promising process for the organic nitrate compound removal and testing at a pilot scale will be done in 2012. (authors)

  9. Guide to treatment technology for contaminated soils

    SciTech Connect

    Tran, H.; Aylward, R.


    This document is a guide for the screening of alternative treatment technologies for contaminated soils. The contents of this guide are organized into: 1. Introduction, II. Utilizing the table, III. Tables: Contamination Versus Technology, TV. Contaminant Waste Groups, and V. References. The four Contaminations Versus Technology tables are designed to identify the effectiveness and/or potential applicability of technologies to some or all compounds within specific waste groups. The tables also present limitations and special use considerations for the particular treatment technology. The phase of development of the technology is also included in the table. The phases are: Available, Innovative, and Emerging technologies. The technologies presented in this guide are organized according to the method of treatment. The four (4) treatment methods are Biological, Solidification/Stabilization, Thermal, and Chemical/Physical Treatment. There are several processing methods; some are well developed and proven, and others are in the development stage.

  10. Ecological risk assessment of contaminated soil.


    Jensen, John; Pedersen, Marianne Bruus


    This review has described three cases of ecological risk assessment. The cases include two heavy metals (Cu and Zn) and an anthropogenic organic chemical (DDT). It concludes that there are at least two major constraints hampering the use of laboratory tests to predict effects under natural field conditions. One key issue is bioavailability, and another is suboptimal conditions or multiple stresses in the field such as climatic stress (drought, frost), predators, competition, or food shortage. On the basis of the presented case studies, it was possible to answer three essential questions often raised in connection to ecological risk assessment of contaminated sites. 1. To what extend does soil screening level (SSL) estimate the risk? The SSL are generally derived at levels corresponding to the lowest observed effect levels in laboratory studies, which often is close to the background levels found in many soils. In the cases of zinc and especially DDT, the SSL seemed quite conservative, whereas for copper they resemble the level at which changes in the community structure of soil microarthropods and the plant community have been observed at contaminated sites. The SSL correspond as a whole relatively well with concentrations where no effects or only minor effects were observed in controlled field studies. However, large variation in field surveys can often make it difficult to conclude to what extent the SSL corresponded to no-effect levels in the field. 2. Do bioassays represent a more realistic risk estimate? Here, there is no firm conclusion. The zinc study in UK showed a better relationship between the outcome of ex situ bioassays and field observations than the SSL. The latter overestimated the risk compared to field observations. However, this would be species dependent, as the sensitivity to metals may vary considerably between recognized test species, even within the same group of organisms, such as Folsomia candida and Folsomia fimetaria or Eisenia fetida

  11. Toxicological relevance of emerging contaminants for drinking water quality.


    Schriks, Merijn; Heringa, Minne B; van der Kooi, Margaretha M E; de Voogt, Pim; van Wezel, Annemarie P


    The detection of many new compounds in surface water, groundwater and drinking water raises considerable public concern, especially when human health based guideline values are not available it is questioned if detected concentrations affect human health. In an attempt to address this question, we derived provisional drinking water guideline values for a selection of 50 emerging contaminants relevant for drinking water and the water cycle. For only 10 contaminants, statutory guideline values were available. Provisional drinking water guideline values were based upon toxicological literature data. The maximum concentration levels reported in surface waters, groundwater and/or drinking water were compared to the (provisional) guideline values of the contaminants thus obtained, and expressed as Benchmark Quotient (BQ) values. We focused on occurrence data in the downstream parts of the Rhine and Meuse river basins. The results show that for the majority of compounds a substantial margin of safety exists between the maximum concentration in surface water, groundwater and/or drinking water and the (provisional) guideline value. The present assessment therefore supports the conclusion that the majority of the compounds evaluated pose individually no appreciable concern to human health. PMID:19766285

  12. TNT transport and fate in contaminated soil

    SciTech Connect

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


    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 mg 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.

  13. Method for treatment of soils contaminated with organic pollutants


    Wickramanayake, Godage B.


    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.

  14. Microbial interactions with organic contaminants in soil: definitions, processes and measurement.


    Semple, Kirk T; Doick, Kieron J; Wick, Lukas Y; Harms, Hauke


    There has been and continues to be considerable scientific interest in predicting bioremediation rates and endpoints. This requires the development of chemical techniques capable of reliably predicting the bioavailability of organic compounds to catabolically active soil microbes. A major issue in understanding the link between chemical extraction and bioavailability is the problem of definition; there are numerous definitions, of varying degrees of complexity and relevance, to the interaction between organic contaminants and microorganisms in soil. The aim of this review is to consider the bioavailability as a descriptor for the rate and extent of biodegradation and, in an applied sense, bioremediation of organic contaminants in soil. To address this, the review will (i) consider and clarify the numerous definitions of bioavailability and discuss the usefulness of the term 'bioaccessibility'; (ii) relate definition to the microbiological and chemical measurement of organic contaminants' bioavailability in soil, and (iii) explore the mechanisms employed by soil microorganisms to attack organic contaminants in soil. PMID:17881105

  15. Bioremediation of uranium contaminated soils and wastes

    SciTech Connect

    Francis, A.J.


    Contamination of soils, water, and sediments by radionuclides and toxic metals from uranium mill tailings, nuclear fuel manufacturing and nuclear weapons production is a major concern. Studies of the mechanisms of biotransformation of uranium and toxic metals under various microbial process conditions has resulted in the development of two treatment processes: (1) stabilization of uranium and toxic metals with reduction in waste volume and (2) removal and recovery of uranium and toxic metals from wastes and contaminated soils. Stabilization of uranium and toxic metals in wastes is accomplished by exploiting the unique metabolic capabilities of the anaerobic bacterium, Clostridium sp. The radionuclides and toxic metals are solubilized by the bacteria directly by enzymatic reductive dissolution, or indirectly due to the production of organic acid metabolites. The radionuclides and toxic metals released into solution are immobilized by enzymatic reductive precipitation, biosorption and redistribution with stable mineral phases in the waste. Non-hazardous bulk components of the waste volume. In the second process uranium and toxic metals are removed from wastes or contaminated soils by extracting with the complexing agent citric acid. The citric-acid extract is subjected to biodegradation to recover the toxic metals, followed by photochemical degradation of the uranium citrate complex which is recalcitrant to biodegradation. The toxic metals and uranium are recovered in separate fractions for recycling or for disposal. The use of combined chemical and microbiological treatment process is more efficient than present methods and should result in considerable savings in clean-up and disposal costs.

  16. Remediating pesticide contaminated soils using solvent extraction

    SciTech Connect

    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 system 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.

  17. Biological degradation of TNT-contaminated soil

    SciTech Connect

    Manning, J.F.; Boopathy, R.


    The concept of using biological slurry reactors to remediate soil contaminated with TNT has been investigated at the laboratory scale. Important parameters include an organic co-substrate and appropriate amounts of nitrogen and phosphorus added as nutrients. Normally, the degradation requires an organic co-substrate. The type of co-substrate can have a significant impact on the rate and extent of degradation. Succinate, malate, molasses, and glucose are all acceptable co-substrates. Molasses, or succinate with added yeast extract and/or peptone, provides superior rates of removal. Consortia of microorganisms isolated from various sites can also degrade TNT. To exploit the microbial system, laboratory scale soil slurry reactors have been operated, achieving reductions in TNT concentrations on the order of 90-99% from initial TNT concentrations of 7,000-10,000 mg/kg. Laboratory scale tests have shown that all of the intermediates can be removed by microbial degradation. Laboratory reactors operated with 15% volume replacement one, two, or three times a week achieved removal of 95-99% of the TNT in the feed soil. This system can reduce TNT concentrations to less than 20 mg/kg in treated soil. In particular, operation of the reactors in an aerobic-anoxic sequenced pattern promotes the conversion of TNT to CO{sub 2} and microbial biomass. Radiolabeling studies demonstrated that 50% of the TNT is mineralized, with 30% of the original labeled TNT being converted to microbial biomass. To take advantage of this technology, a field demonstration in which the soil slurry reactor is being used to degrade explosives-contaminated soil is currently being conducted.

  18. Procedures for sampling radium-contaminated soils

    SciTech Connect

    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 or 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.

  19. Dynamics of soil parameters relevant for humanitarian demining

    NASA Astrophysics Data System (ADS)

    Obhođaš, Jasmina; Vdović, Neda; Valković, Vlado


    In this paper we analyzed characteristics of 6 different soils from the test field at the Ruđer Bošković Institute. Many soil properties relevant for the performance of humanitarian demining tools strongly depend on water content. This is an effort to understand better the soil moisture variability and to find soil parameters that can predict the water content regarding the weather conditions. Such knowledge will allow to optimize demining operations. To gather the main parameters like field capacity, rate and delay of water infiltration and soil water retention which are all related to soil texture, daily time-series of soil moisture from August to November 2001, where analyzed.

  20. Aromatic plant production on metal contaminated soils.


    Zheljazkov, Valtcho D; Craker, Lyle E; Xing, Baoshan; Nielsen, Niels E; Wilcox, Andrew


    Field and container experiments were conducted to assess the feasibility of growing aromatic crops in metal contaminated areas and the effect of metals on herbage and oil productivity. The field experiments were conducted in the vicinities of the Non-Ferrous Metals Combine (Zn-Cu smelter) near Plovdiv, Bulgaria using coriander, sage, dill, basil, hyssop, lemon balm, and chamomile grown at various distances from the smelter. Herbage essential oil yields of basil, chamomile, dill, and sage were reduced when they were grown closer to the smelter. Metal removal from the site with the harvestable plant parts was as high as 180 g ha(-1) for Cd, 660 g ha(-1) for Pb, 180 g ha(-1) for Cu, 350 g ha(-1) for Mn, and 205 g ha(-1) for Zn. Sequential extraction of soil demonstrated that metal fractionation was affected by the distance to the smelter. With decreasing distance to the smelter, the transfer factor (TF) for Cu and Zn decreased but increased for Cd, while the bioavailability factor (BF) for Cd, Pb, Cu, Mn, and Zn decreased. Scanning electron microscopy and X-ray microanalyses of contaminated soil verified that most of the Pb, Cd, Mn, Cu, and Zn were in the form of small (<1 microm) particles, although there were larger particles (1-5 microm) with high concentrations of individual metals. This study demonstrated that high concentrations of heavy metals in soil or growth medium did not result in metal transfer into the essential oil. Of the tested metals, only Cu at high concentrations may reduce oil content. Our results demonstrated that aromatic crops may not have significant phytoremediation potential, but growth of these crops in metal contaminated agricultural soils is a feasible alternative. Aromatic crops can provide economic return and metal-free final product, the essential oil. PMID:18353428

  1. Analytical characterization of contaminated soils from former manufactured gas plants

    SciTech Connect

    Haeseler, F.; Blanchet, D.; Vandecasteele, J.P.; Druelle, V.; Werner, P.


    Detailed analytical characterization of the organic matter (OM) of aged polluted soils from five former manufactured gas plants (MGP) and of two coal tars was completed. It was aimed at obtaining information relevant to the physicochemical state of the polycyclic aromatic hydrocarbon (PAH) pollutants and to their in-situ evolution in time. Overall characterization of total OM (essentially polluting OM) was carried out directly on soil samples with or without prior extraction with solvent. It involved a technique of pyrolysis/oxidation coupled to flame ionization/thermal conductivity detection. Extracts in solvent were fractionated by liquid chromatography into saturated hydrocarbons, PAH, and resins, the first two fractions being further characterized by gas chromatography and mass spectrometry. The compositions of OM of soils were found to be very similar. A total of 28% of organic carbon, including all PAH, was extractable by solvent. The compositions of coal tars were qualitatively similar to those of OM of MGP soils but with a higher proportion (48%) of total extractable OM and of PAH, in particular lower PAH. Contamination of MGP soils appeared essentially as coal tar having undergone natural attenuation. The constant association of PAH with heavy OM in MGP soils is important with respect to the mobility and bioaccessibility of these pollutants.

  2. Enhanced bioremediation of PAH contaminated soils from coal processing sites

    SciTech Connect

    Joshi, M.M.; Lee, S.


    The polycyclic aromatic hydrocarbons (PAH) are a potential hazard to health due to their carcinogenic, mutagenic nature and acute toxicity and there is an imminent need for remediation of PAH contaminated soils abounding the several coke oven and town gas sites. Aerobic biological degradation of PAHs is an innovative technology and has shown high decontamination efficiencies, complete mineralization of contaminants, and is environmentally safe. The present study investigates the remediation of PAH contaminated soils achieved using Acinetobacter species and fungal strain Phanerochaete Chrysosporium. The soil used for the experiments was an industrially contaminated soil obtained from Alberta Research Council (ARC) primary cleanup facility, Alberta, Canada. Soil characterization was done using High Performance Liquid Chromatography (HPLC) to qualitatively and quantitatively determine the contaminants in the soil. Artificially contaminated soil was also used for some experiments. All the experiments were conducted under completely mixed conditions with suitable oxygen and nutrient amendments. The removal efficiency obtained for various PAHs using the two microorganisms was compared.

  3. Risk perception of heavy metal soil contamination and attitudes toward decontamination strategies.


    Weber, O; Scholz, R W; Bühlmann, R; Grasmück, D


    Contaminated soils are a common environmental risk all over the world. One major source of risk is heavy metal soil contamination caused by industrial emissions. This quasiexperimental study investigated the perception of these risks by exposed and nonexposed people, their attitudes toward bioremediation methods using hyperaccumulating plants, and the influence of long-term aspects of sustainability on the acceptance of bioremediation methods. Major findings were that people living in a contaminated area perceived the risk of the heavy metal soil contamination as higher than the general risk of contamination. Second, a factor analysis showed that the factors dread, control, and catastrophic potential were relevant for the perception and valuation of low-dose environmental risks such as the contamination of the investigated area. In addition, a cluster analysis showed that the risk of heavy metal soil contamination was perceived as similar to that of oil contamination, ozone layer, preservatives and genetic technology. It was perceived indifferently with regard to dread. The uncontrollability of heavy metal soil contamination was estimated as medium, and its catastrophic potential as low. Third, exposed and nonexposed participants preferred bioremediation methods to classical methods (e.g., excavation and chemical treatment of the soil), because they perceived the environmental and esthetical performance of the bioremediation as important criteria. Sustainability or precautionary issues, such as the prevention of harm for future generations, were highly correlated with the acceptance of the use of bioremediation methods in people's residential areas. PMID:11798130

  4. Bioremediation of petroleum contaminated soil using vegetation. A microbial study

    SciTech Connect

    Lee, E.; Banks, M.K. )


    The degradation of selected petroleum hydrocarbons in the rhizosphere of alfalfa was investigated in a greenhouse experiment. Petroleum contaminated and uncontaminated soils were spiked with 100 ppm of polynuclear aromatic and aliphatic hydrocarbons. Unspiked, uncontaminated soil was used as a control. Microbial counts for soils with and without plants for each soil treatment were performed 4, 8, 16, and 24 weeks after planting. Microbial numbers were substantially greater in soil with plants when compared to soil containing no plants, indicating that plant roots enhanced microbial populations in contaminated soil. Soil treatments had no effect on microbial numbers in the presence of plants. 12 refs., 3 figs., 1 tab.


    SciTech Connect



    Contamination of soils, water, and sediments by radionuclides and toxic metals from uranium mill tailings, nuclear fuel manufacturing and nuclear weapons production is a major concern. Studies of the mechanisms of biotransformation of uranium and toxic metals under various microbial process conditions has resulted in the development of two treatment processes: (i) stabilization of uranium and toxic metals with reduction in waste volume and (ii) removal and recovery of uranium and toxic metals from wastes and contaminated soils. Stabilization of uranium and toxic metals in wastes is accomplished by exploiting the unique metabolic capabilities of the anaerobic bacterium, Clostridium sp. The radionuclides and toxic metals are solubilized by the bacteria directly by enzymatic reductive dissolution, or indirectly due to the production of organic acid metabolites. The radionuclides and toxic metals released into solution are immobilized by enzymatic reductive precipitation, biosorption and redistribution with stable mineral phases in the waste. Non-hazardous bulk components of the waste such as Ca, Fe, K, Mg and Na released into solution are removed, thus reducing the waste volume. In the second process uranium and toxic metals are removed from wastes or contaminated soils by extracting with the complexing agent citric acid. The citric-acid extract is subjected to biodegradation to recover the toxic metals, followed by photochemical degradation of the uranium citrate complex which is recalcitrant to biodegradation. The toxic metals and uranium are recovered in separate fractions for recycling or for disposal. The use of combined chemical and microbiological treatment process is more efficient than present methods and should result in considerable savings in clean-up and disposal costs.


    EPA Science Inventory

    Treating large volumes of contaminated soil at Superfund sites is costly. he Superfund Amendments and Reauthorization Act (SARA), and the Resource Conservation and Recovery Act (RCRA) have provisions, which regulate the removal treatment, and ultimate disposal of contaminated soi...


    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....

  8. Soils as a buffer of contaminants in catchments

    NASA Astrophysics Data System (ADS)

    Evrard, Olivier


    Human activities deliver large quantities of contaminants into the environment through atmospheric emissions or direct releases. As many of those contaminants are particle-reactive, they bind strongly to the finest particles or on their organic matter fraction once they deposit onto soils. Contaminants may subsequently migrate in depth of the soil depending on their physico-chemical characteristics. They may also be redistributed along hillslopes in association with particles during soil erosion events and may be subsequently supplied to rivers, preventing to meet the international environmental targets (e.g. in the framework of the EU Water Framework Directive). In regions where soil erosion rates are low to moderate, a large quantity of particle-reactive contaminants may accumulate in soils that constitute a reservoir of pollutants that may be delivered to rivers during decades or centuries. This session will focus on the specific role played by soils as a reservoir of contaminants at the catchment scale. A better understanding of this role and a quantification of the persistence of contaminants in this reservoir will provide crucial insights to guide the implementation of efficient mitigation measures. Contributions to this session may address any aspect of particle-borne contaminant transfer at the catchment scale, with an emphasis on the role played by soils in their storage and transfer. Field-based or modeling studies may focus either on specific pollutants or on a wider range of substances, e.g. metals, radionuclides, organic contaminants. Key themes may include: • Contaminant budget at the hillslope vs. the catchment scales; • Evaluation of the contribution of the regional vs. local contamination sources; • Evaluation of the contaminant removal from soils by degradation vs. soil erosion; • Quantifying the persistence of contaminants in soils; • Discrimination between the legacy and the contemporary supply of contaminants to soils.

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


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


    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.

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


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


    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. Surface interactions relevant to space station contamination problems

    NASA Technical Reports Server (NTRS)

    Dickinson, J. T.


    The physical and chemical processes at solid surfaces which can contribute to Space Station contamination problems are reviewed. Suggested areas for experimental studies to provide data to improve contamination modeling efforts are presented.

  12. Soil contamination in China: current status and mitigation strategies.


    Zhao, Fang-Jie; Ma, Yibing; Zhu, Yong-Guan; Tang, Zhong; McGrath, Steve P


    China faces great challenges in protecting its soil from contamination caused by rapid industrialization and urbanization over the last three decades. Recent nationwide surveys show that 16% of the soil samples, 19% for the agricultural soils, are contaminated based on China’s soil environmental quality limits, mainly with heavy metals and metalloids. Comparisons with other regions of the world show that the current status of soil contamination, based on the total contaminant concentrations, is not worse in China. However, the concentrations of some heavy metals in Chinese soils appear to be increasing at much greater rates. Exceedance of the contaminant limits in food crops is widespread in some areas, especially southern China, due to elevated inputs of contaminants, acidic nature of the soil and crop species or cultivars prone to heavy metal accumulation. Minimizing the transfer of contaminants from soil to the food chain is a top priority. A number of options are proposed, including identification of the sources of contaminants to agricultural systems, minimization of contaminant inputs, reduction of heavy metal phytoavailability in soil with liming or other immobilizing materials, selection and breeding of low accumulating crop cultivars, adoption of appropriate water and fertilizer management, bioremediation, and change of land use to grow nonfood crops. Implementation of these strategies requires not only technological advances, but also social-economic evaluation and effective enforcement of environmental protection law. PMID:25514502

  13. The effect of contaminant aging upon soil washing removal efficiencies for lead contaminated soils

    SciTech Connect

    Cline, S.R.; Reed, B.E.; Moore, R.E.


    The objective of this research was to investigate lead removal efficiencies from various soils using a variety of washing solutions. Most soil types have a strong affinity for lead. Thus, it is plausible to expect washing solutions that are capable of removing lead could also remove other divalent heavy metals. Four soil samples from the eastern US were collected and characterized for this study. The study soils were then spiked to approximate lead concentrations of 1,000 and 10,000 mg Pb/kg soil. The efficiencies of six washing solutions in removing lead from the contaminated soils were then investigated via lab-scale batch washing experiments. Unlike current field-scale soil washing practices, all particle size fractions were washed and recovered in these experiments. (Solutions investigated include: tap water, HCl, EDTA, HNO{sub 3}, CH{sub 3}COOH, and CaCl{sub 2}.) In order to examine the effect of aging upon soil washing efficiencies, some of the spiked soils were washed a second time after an aging period of nearly 2 years.


    EPA Science Inventory

    Soil vapor phase contaminants commonly include combinations of chlorinated ethenes and petroleum hydrocarbons. Many chlorinated ethenes and petroleum hydrocarbons are readily degradable by a range of aerobic soil microorganisms, making the use of biological systems for degrading ...

  15. 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...

  16. Testing amendments for remediation of military range contaminated soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Military range soils are often strongly contaminated with metals. Information on effectiveness of remediation techniques on these soils is scarce. We tested effectiveness of compost and mineral treatments for remediation of military range soil collected in Aberdeen, MD. The soil was barren due to...

  17. Comprehensive methodology for ecological risk assessment of contaminated soils

    SciTech Connect

    Kuperman, R.G.


    Development of a comprehensive methodology for ecological risk assessment and monitoring of contaminated soils is essential to assess the impacts of environmental contaminants on soil community and biologically-mediated processes in soil. The proposed four-step plan involves (1) a thorough survey of the soil community to establish biodiversity and a base-line community structure, (2) toxicity trials on indicator species and whole soil invertebrate communities, (3) laboratory and field tests on indicator processes and (4) the use of statistical and simulation models to ascertain changes in the soil ecosystems. This methodology was used in portions of the US Army`s Aberdeen Proving Ground, Maryland as part of an ecological risk assessment. Previous soil analyses showed extensive surface soil contamination with metals, nitrate and PCBs. Preliminary results from field surveys of soil invertebrate communities showed significant reductions in total abundance of animals, reductions in the abundance of several taxonomic and functional groups of soil invertebrates, and changes in the activity of epigeic arthropods in contaminated areas when compared with the local ``background`` area. Laboratory tests also demonstrated that microbial activity and success of egg hatching of ground beetle Harpalus pensylvanicus were reduced in contaminated soils. These results suggest that impacts to soil ecosystems should be explicitly considered in ecological risk assessment. The proposed comprehensive methodology appears to offer an efficient and potentially cost saving tool for remedial investigations of contaminated sites.


    EPA Science Inventory

    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 from selected DOE waste sites will be characterized for specific organic and metal contaminants and hydraulic per...


    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...

  20. Evaporation of petroleum products from contaminated soils

    SciTech Connect

    Kang, S.H.; Oulman, C.S.


    Bioremediation can remove petroleum products from soil that has been contaminated by leaking underground storage tanks, but abiotic processes such as evaporation can contribute significantly to the overall removal process. The mathematical model described in this paper was developed to predict the evaporation rate of volatile liquids from petroleum-contaminated sand. The model is based on simple concepts relating to molecular diffusion embodied in the theory underlying the estimation of binary diffusivities using measurements made with an Arnold diffusion cell. The model in its simplified form indicates that the rate of evaporation for a particular volatile liquid is proportional to the square root of the product of diffusivity and partial pressure divided by the molecular weight of the liquid. This in part explains why evaporative losses from sand are so much higher for gasoline than for diesel fuel. The model also shows that the time for evaporation is directly proportional to the square of the depth dried out and inversely proportional to the vapor pressure of the volatile liquid. The model was tested using gravimetric measurements of the evaporation of n-heptane, unleaded gasoline, and diesel fuel from sand under laboratory conditions.

  1. Partitioning of heavy metals in a soil contaminated by slag: A redistribution study

    SciTech Connect

    Bunzl, K.; Trautmannsheimer, M.; Schramel, P.


    In order to interpret reasonably the partitioning of heavy metals in a contaminated soil as observed from applying a sequential extraction procedure, information on possible redistribution processes of the metals during the various extraction steps is essential. For this purpose, sequential extraction was used to study the chemical partitioning of Ag, Cu, Ni, Pb, and Zn in a soil contaminated wither by a slag from coal firing or by a slag from pyrite roasting. Through additional application of sequential extraction to the pure slags as well as to the uncontaminated soil, it was shown that during the various extraction steps applied to the soil/slag mixtures, substantial redistribution processes of the metals between the slag- and soil particles can occur. In many cases, metals ions released during the extraction with acid hydroxylamine or acid hydrogen peroxide are partially readsorbed by solid constituents of the mixture and will therefore be found in the subsequent fractions extracted. As a result, one has to realize that (1) it will be difficult to predict the chemical partitioning of these metals in contaminated soils by investigating pure slags only, and (2) information on the partitioning of a metal in a slag contaminated soil will not necessarily give any relevant information on the form of this metal in the slag or in the slag/soil mixture, because the redistribution processes during sequential extraction will not be the same as those occurring in the soil solution under natural conditions.

  2. Current methods for evaluating the bioavailability of chemicals from contaminated soils using soil invertebrates

    SciTech Connect

    Lanno, R.P.


    Contaminated soils are an extremely complex, variable matrix where many modifying factors of toxicity (e.g., particle size, organic matter content) alter the availability of chemicals to biota. Although many methods have been standardized for assessing the toxicity of contaminated soils to invertebrates and plants, few studies have actually addressed the issue of contaminant bioavailability from soils. Since bioavailability is a measure of uptake of contaminants from the soil by living organisms, one approach to determining bioavailability is to measure residues of contaminants in biota. Body residues related to a specific lethal or sublethal toxicity endpoint offer the unique opportunity to relate bioavailability to biological response. This paper will present an overview of the use of body residues in assessing the bioavailability of soil contaminants by earthworms and soil arthropods. The applications of body residues in the development of soil quality guidelines will also be discussed.

  3. 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.


    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

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


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


    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

  5. 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


    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.

  6. Spectral induced polarization signature of contaminated soil

    NASA Astrophysics Data System (ADS)

    Schwartz, N.; Huisman, J. A.; Shefer, I.; Furman, A.


    Spectral induced polarization (SIP) signatures of porous media contaminated with non aqueous phase liquids (NAPL) were measured using an accurate impedance meter. The samples were prepared by mixing air-dried sand with 15% by weight of bentonite clay, tap water and either diesel fuel or motor oil. Next, the soil was packed in a column and left for 24 hr before electrical measurements were performed. For all the samples, water saturation was constant (Sw = 0.47) and the NAPL saturation was 0 (control), 5, or 15 percent. Counter-intuitively, the results show that addition of NAPL to the porous media resulted in an increase of the real part of the complex conductivity. Evidently, for each type of contaminant, an increase in the contaminant saturation resulted in an increase in the real part of the conductivity. The imaginary part of the complex conductivity showed a reversed behavior: higher NAPL saturation resulted in a reduction of the imaginary part of the complex conductivity. For both the real and the imaginary part of the complex conductivity, the effect of NAPL on the complex electrical conductivity was more significant for motor oil than for diesel fuel. In addition to the electrical measurements, we also performed an extraction experiment to examine the effect of the presence of NAPL on the electrical conductivity (EC) of the pore water. The results from the extraction experiment showed that addition of NAPL to the porous media resulted in an increase of the pore water EC. We argue that this increase in the real part of the complex conductivity is related to adsorption of organic polar compounds from the NAPL onto the mineral surface and the associated release of inorganic ions from the mineral surface to the pore water. These exchange processes affect both the surface and the pore water conductivity. In addition, we suggest that the decrease in polarization (associated with the imaginary part of the complex conductivity) of the NAPL contaminated porous media

  7. Remediation of contaminated soils and sludges by green plants

    SciTech Connect

    Cunningham, S.D.; Berti, W.R.; Huang, J.W.


    The potential of green plants to remove, contain, or render harmless contaminants in soils and sludges is actively being explored in an increasing number of laboratories throughout the world. This approach, which has been termed phytoremediation, exploits plants, soil amendments, and plant-associated microbiota to remediate contaminated soils. As an in situ stabilization technique, soil amendment with fertilizers, biosolids, or certain industrial by-products alters the chemical and physical nature of the contaminant in the soil matrix, thus reducing its available to biological processes. The site is then vegetated with plants that can (1) grow in the resulting soil matrix; (2) reduce leaching through the soil profile by absorbing, sequestering, or degrading residual contaminants in the soil solution; and (3) minimize wind and rain erosion. The process is known as phytostabilization, or simply site stabilization, and borrows heavily on mine reclamation techniques. As a site decontamination technique, the soil is treated to increase the availability of the contaminant to biological processes and then planted with plants that (1) accumulate the contaminant and are harvested for further pollutant destruction, sequestration, or reclamation or (2) use plant or plant-associated microbial processes to destroy the pollutant in situ.

  8. Apparatus for treatment of soils contaminated with organic pollutants


    Wickramanayake, Godage B.


    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.

  9. 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 ...

  10. Control and assessment of the hydrocarbon contamination of Ukrainian soils

    NASA Astrophysics Data System (ADS)

    Miroshnichenko, N. N.


    Regularities governing the self-purification of soils from oil hydrocarbons, as well as migration of hydrocarbons, and the effect on the water-physical properties and fertility of soils were revealed in a series of experiments. A system of ecological, economic, and reclamation standards was proposed for regulating economic activities in the case of soil contamination with hydrocarbons.


    EPA Science Inventory

    Reduction in exposure to soil metal contamination has typically been accomplished by soil removal and off site disposal, by covering, or by diluting with uncontaminated soil. Cost, logistical concerns, and regulatory requirements associated with excavation and disposal or ex-situ...

  12. Waste reduction by separation of contaminated soils during environmental restoration

    SciTech Connect

    Roybal, J.A.; Conway, R.; Galloway, B.; Vinsant, E.; Slavin, P.; Guerin, D.


    During cleanup of contaminated sites, Sandia National Laboratories, New Mexico (SNL/NM) frequently encounters soils with low-level radioactive contamination. The contamination is not uniformly distributed, but occurs within areas of clean soil. Because it is difficult to characterize heterogeneously contaminated soils in detail and to excavate such soils precisely using heavy equipment, it is common for large quantities of uncontaminated soil to be removed during excavation of contaminated sites. This practice results in the commingling and disposal of clean and contaminated material as low-level waste (LLW), or possibly low-level mixed waste (LLMW). Until recently, volume reduction of radioactively contaminated soil depended on manual screening and analysis of samples, which is a costly and impractical approach and does not uphold As Low As Reasonably Achievable (ALARA) principles. To reduce the amount of LLW and LLMW generated during the excavation process, SNL/NM is evaluating two alternative technologies. The first of these, the Segmented Gate System (SGS), is an automated system that located and removes gamma-ray emitting radionuclides from a host matrix (soil, sand, dry sludge). The matrix materials is transported by a conveyor to an analyzer/separation system, which segregates the clean and contaminated material based on radionuclide activity level. The SGS was used to process radioactively contaminated soil from the excavation of the Radioactive Waste Landfill. The second technology, Large Area Gamma Spectroscopy (LAGS), utilizes a gamma spec analyzer suspended over a slab upon which soil is spread out to a uniform depth. A counting period of approximately 30 minutes is used to obtain a full-spectrum analysis for the isotopes of interest. The LAGS is being tested on the soil that is being excavated from the Classified Waste Landfill.

  13. Contamination of persistent organic pollutants (POPs) and relevant management in China.


    Tieyu, Wang; Yonglong, Lu; Hong, Zhang; Yajuan, Shi


    The status of typical persistent organic pollutant (POP) contamination in many media (e.g., farm produce, soil, human milk, water, and sediments) was surveyed and China's relevant countermeasures for controlling POPs were analyzed in this paper. The results showed that the proportion of organochlorine pesticides (OCPs) to all kinds of pesticides has descended significantly since 1983 when the OCPs were forbidden from being used. The spatial distribution characteristic of pesticide application in the whole country was as follows: southeast>central>northwest. The pesticide residues in food with high fat and high protein content were more than that in foodstuffs. The residual concentration in soil in the whole country was as follows: south>central>north. Furthermore, in vegetable fields, the residual concentration was higher than that in crop fields. As for human milk, the retained amount tended to decrease. In the recent two decades, although the reduction was 81.5%, it was still higher than that in some developed European and American countries. The rank of the residual concentrations of OCPs in different media was: human milk>animal foodstuff>soil>vegetable food>water and sediment. The initial relevant POP management in China can be traced back to 1982 when the Ordinance of Pesticide Management was enacted. Now, environmental control of POPs in China is close to the international level. The legal management system of POPs can be divided into four facets, including 3 regulations, 6 ordinances, and 20 standards. However, on the whole, most of the existing regulations do not refer to POPs directly. Only some clauses mention POPs and lack pertinent, explicit statements on POP pollution and control. Legislation is urgently needed for more effective environmental management to enhance POP control. PMID:15982740

  14. Biological Treatment of Petroleum in Radiologically Contaminated Soil

    SciTech Connect



    This chapter describes ex situ bioremediation of the petroleum portion of radiologically co-contaminated soils using microorganisms isolated from a waste site and innovative bioreactor technology. Microorganisms first isolated and screened in the laboratory for bioremediation of petroleum were eventually used to treat soils in a bioreactor. The bioreactor treated soils contaminated with over 20,000 mg/kg total petroleum hydrocarbon and reduced the levels to less than 100 mg/kg in 22 months. After treatment, the soils were permanently disposed as low-level radiological waste. The petroleum and radiologically contaminated soil (PRCS) bioreactor operated using bioventing to control the supply of oxygen (air) to the soil being treated. The system treated 3.67 tons of PCRS amended with weathered compost, ammonium nitrate, fertilizer, and water. In addition, a consortium of microbes (patent pending) isolated at the Savannah River National Laboratory from a petroleum-contaminated site was added to the PRCS system. During operation, degradation of petroleum waste was accounted for through monitoring of carbon dioxide levels in the system effluent. The project demonstrated that co-contaminated soils could be successfully treated through bioventing and bioaugmentation to remove petroleum contamination to levels below 100 mg/kg while protecting workers and the environment from radiological contamination.

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


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


    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 180(th) 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 180(th) 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 180(th) 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. PMID:26587892

  16. Bioremediation of gasoline-contaminated soil using poultry litter

    SciTech Connect

    Gupta, G; Tao, J.


    Contaminated soil, excavated from around a leaking underground gasoline storage tank, is commonly subjected to thermal degradation to remove the gasoline. Bioremediation as an alternative treatment technology is now becoming popular. The important hydrocarbon-degrading bacteria include Pseudomonas, Arthrobacter, and Flavobacterium. Poultry litter contains a large number of microorganisms, including Pseudomonas, as well as many inorganic nutrients and organic biomass that may assist in biodegrading gasoline in contaminated soil. During bioremediation of contaminated soil, microbial densities are known to increase by 2-3 orders of magnitude. However, bioremediation may result in a increase in the toxic characteristics of the soil due to the production of potentially toxic degradation intermediates. The objective of this research was to study the influence of the addition of poultry litter on the bioremediation of gasoline-contaminated soil by quantifying the changes in the densities of microorganisms and by monitoring the toxicity of the degradation products. 25 refs., 5 figs., 2 tabs.

  17. Hydrocarbon status of soils under different ages of oil contamination

    NASA Astrophysics Data System (ADS)

    Gennadiev, A. N.; Pikovskii, Yu. I.; Kovach, R. G.; Koshovskii, T. S.; Khlynina, N. I.


    Modifications of the hydrocarbon status (HCS) of soils at the stages of the injection input of oil pollutants and the subsequent self-purification of the soil layer from technogenesis products have been revealed in studies conducted on an oil field. Comparison with the HCS of background soils has been performed. Changes in the composition and concentration of bitumoids, polycyclic aromatic hydrocarbons (PAHs), and hydrocarbon gases have been established. The HCS of a freshly contaminated soil is characterized by the predominance of butane (the highest component) in the gaseous phase, an abrupt increase in the concentration of second-kind bitumoids, and a 100-fold increase in the content of PAHs compared to the background soil. In the old contaminated soil, free and fixed methane becomes the predominant gas; the content of bitumoids in the upper soil horizons is lower than in the freshly contaminated soils by two orders of magnitude but higher than in the background soil by an order of magnitude; the PAH composition in the soil with old residual contamination remains slightly more diverse than in the background soil.

  18. Relevance of mineral-organic associations in cryoturbated permafrost soils

    NASA Astrophysics Data System (ADS)

    Gentsch, Norman; Mikutta, Robert; Bárta, Jiří; Čapek, Petr; Gittel, Antje; Richter, Andreas; Šantrůčková, Hanna; Schnecker, Jörg; Shibistova, Olga; Urich, Tim; Wild, Birgit; Guggenberger, Georg


    uppermost permafrost. In topsoil horizons, mineralization rates showed a similar pattern for MOM and the bulk soil controls. In contrast, even higher MOM respiration rates then the bulk control were found in the cryoturbated OM-rich pockets and permafrost horizons. These findings deviate from temperate soil environments where MOM is considered to contribute to a 'stabilized pool' with mean residence times from hundreds to thousands of years. Statistical analysis indicated that mineral-organic interactions primarily occurred with poorly crystalline Fe and Al phases and Fe/Al-OM complexes. However, the minor desorption of organic polyelectrolytes by NaH2PO4 in permafrost soils indicated that significantly lower amounts of OC were bound by ligand exchange to Fe and Al minerals or the edges of clay minerals in permafrost soils compared to the temperate reference soils. Therefore, stabilization of OM by mineral surfaces or polyvalent metal ions appears to be of minor relevance in arctic environments compared to temperate soils.

  19. Bioremediation of leachate and soil contaminated with petroleum products

    SciTech Connect

    Yocum, P.S.


    Petroleum products are generally accepted to be biodegradable, whether they are contaminating a liquid or solid phase. Considerable reference material exist to support this ascertain. However, no parameters exist for design of engineered treatment systems and little is known about how mixed cultures degrade sparingly soluble substrates, particularly in the soil environment. Further the heterogeneity of contaminant distribution in the soil environment, inhibit understanding of the processes involved. This dissertation is an attempt to provide methodologies for the assessment of biodegradation of petroleum products in these environments, together with development of procedures applicable to assessment of remediation in soils with heterogenous distribution of contaminants.

  20. Activity of antibiotics in contaminated wounds containing clay soil.


    Roberts, A H; Rye, D G; Edgerton, M T; Rodeheaver, G T; Edlich, R F


    Most traumatic wounds are contaminated to some degree by soil and run a high risk of infection. The presence of soil in wounds interferes with natural tissue defenses, which include phagocytosis and serum bactericidal capacity. The experimental studies reported herein clearly demonstrate that soil also limits the antibacterial effects of specific antibiotics. This inactivation appears to be the result of a chemical reaction between the charged antibiotics and the soil particles. PMID:434335

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


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


    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. PMID:22702809

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

    NASA Astrophysics Data System (ADS)

    Petruzzelli, G.


    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

  3. Bioremediation of lead contaminated soil with Rhodobacter sphaeroides.


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


    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. PMID:27179240

  4. Kinetics of Cd Release from Some Contaminated Calcareous Soils

    SciTech Connect

    Sajadi Tabar, S.; Jalali, M.


    Contamination of soils with heavy metals may pose long-term risk to groundwater quality leading to health implications. Bioavailability of heavy metals, like cadmium (Cd) is strongly affected by sorption and desorption processes. The release of heavy metals from contaminated soils is a major contamination risks to natural waters. The release of Cd from contaminated soils is strongly influenced by its mobility and bioavailability. In this study, the kinetics of Cd desorption from ten samples of contaminated calcareous soils, with widely varying physicochemical properties, were studied using 0.01 M EDTA extraction. The median percentage of Cd released was about 27.7% of the total extractable Cd in the soils. The release of Cd was characterized by an initial fast release rate (of labile fractions) followed by a slower release rate (of less labile fractions) and a model of two first-order reactions adequately describes the observed release of Cd from the studied soil samples. There was positive correlation between the amount of Cd released at first phase of release and Cd in exchangeable fraction, indicating that this fraction of Cd is the main fraction controlling the Cd in the kinetic experiments. There was strongly negative correlation between the amount of Cd released at first and second phases of release and residual fraction, suggesting that this fraction did not contribute in Cd release in the kinetic experiments. The results can be used to provide information for evaluation of Cd potential toxicity and ecological risk from contaminated calcareous soils.

  5. Humus-assisted cleaning of heavy metal contaminated soils

    NASA Astrophysics Data System (ADS)

    Borggaard, Ole K.; Rasmussen, Signe B.


    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.

  6. As Leaching into Fresh Water from Highly Contaminated Hawaiian Soils

    NASA Astrophysics Data System (ADS)

    Niklis, N. J.; Rubin, K. H.; El-Kadi, A. I.


    Arsenic contamination of current and former agricultural soils in Hawaii is an unfortunate legacy of plantation era agricultural practices. Here, we report an investigation of As mobility in fresh water from highly contaminated (0.8 % As) A-zone Hawaiian andisols from the Hamakua Coast of the Island of Hawai’i. Aliquots of the same acidic soil (pH= 5.0) were exposed to fresh water for varying lengths of time and analyzed to quantify the fraction of As and other elements leached from the soil relative to concentrations determined by total digestion. A maximum of 0.04% of As and 0.05% of Fe were removed from the soils in initial rinses and multi-day leaches using 18 megaohm Millipore water, in experiments lasting up to 35 days. Arsenic concentrations were highest in initial soil rinses, indicating that a small fraction of the total As in the soil is either loosely bound or present as a fine-grained, soluble As-bearing phase. During subsequent leaching experiments, arsenic and most other inorganic ions that we analyzed for reached equilibrium after 3 days; Fe reached equilibrium concentrations after 10 days. All soil solutions contained As levels that exceeded the EPA acceptable drinking water limit of 0.01 ppm. However, contaminant transport modeling suggests that As contaminated leachates would not migrate substantially from this site, so that local isolation and storage of contaminated soils would likely be an acceptable containment method.


    EPA Science Inventory

    Techniques were investigated for in-situ treatment of hazardous wastes that could be applied to contaminated soils. Included were chemical treatment methods, biological treatment, photochemical transformations and combination methods. Techniques were developed based on fundamenta...

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


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


    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). PMID:23307052

  9. Decreasing the contamination and toxicity of a heavily contaminated soil by in situ bioremediation

    NASA Astrophysics Data System (ADS)

    Groudev, Stoyan; Georgiev, Plamen; Spasova, Irena; Nikolova, Marina


    An experimental plot of 140 m2 consisting of acidic soil heavily contaminated with uranium, non-ferrous metals (mainly Cu, Zn and Cd) and arsenic was treated in situ under real field conditions using the activity of the indigenous soil microflora. This activity was enhanced by suitable changes of some essential environmental factors such as pH and water, oxygen and nutrient contents of the soil. The treatment was connected with solubilization and removal of contaminants from the top soil layers (horizon A) due to the joint action of the soil microorganisms (mainly acidophilic chemolithotrophic bacteria) and leach solutions (diluted sulphuric acid). The dissolved contaminants were transferred to the soil horizon B and were removed from the soil profile through a system of drainage collecting pipes. The contaminated soil effluents were treated by means of a multi-component passive system consisting of an anoxic alkalizing drain, a permeable reactive multibarrier and a rock filter. The contamination and toxicity of the soil were regularly tested during the cleaning procedure and were considerably decreased at the end of the treatment.

  10. Microbial ecology and transformations associated with munitions contaminated soils

    SciTech Connect

    Martin, J.L.; Li, Z.; Kokjohn, T.A.; Shea, P.J.; Comfort, S.D.


    Many acres of soil at the former Nebraska Ordnance Plant (NOP) are contaminated with TNT and other munitions residues. In some areas, solid phase TNT is present and controls the concentration of the soil solution. Native microbial populations in uncontaminated soils similar to those at the NOP site were severely reduced when solid phase TNT was allowed to control the soil solution TNT concentration. However, examination of NOP soil revealed an active population of Pseudomonas sp. A single species that could utilize TNT as a sole C source was isolated from the contaminated soil and tentatively identified as Pseudomonas corrugata through the BIOLOG system. Subsequent growth and characterization experiments indicate that the Pseudomonad metabolizes TNT while in the exponential phase of growth in medium containing glucose as a sole N source. Low TNT mineralization rates (measured by CO{sub 2} evolution) in soil and media using the various isolates suggest reduced availability due to sorption and incorporation of transformation intermediates into the organic matrix and microbial biomass. Pretreatment of TNT by acid-metal catalyzed reduction resulted in an initially higher rate of mineralization following addition to TNT-contaminated soil. Observations indicate more rapid microbial utilization of the 2,4,6-triaminotoluene (TAT) reduction product and its spontaneous decay product, methylphloroglucinol (2,4,6-trihydroxytoluene), than TNT. Abiotic pretreatment may be useful in enhancing microbial transformation and detoxification of TNT in highly contaminated soils.

  11. Toxicity assessment of contaminated soils from an antitank firing range.


    Robidoux, Pierre Yves; Gong, Ping; Sarrazin, Manon; Bardai, Ghalib; Paquet, Louise; Hawari, Jalal; Dubois, Charles; Sunahara, Geoffrey I


    Explosives are released into the environment at production and processing facilities, as well as through field use. These compounds may be toxic at relatively low concentrations to a number of ecological receptors. A toxicity assessment was carried out on soils from an explosive-contaminated site at a Canadian Forces Area Training Center. Toxicity studies on soil organisms using endpoints such as microbial processes (potential nitrification activity, dehydrogenase activity, substrate-induced respiration, basal respiration), plant seedling and growth (Lactuca sativa and Hordeum vulgare), and earthworm (Eisenia andrei) growth and reproduction were carried out. Results showed that 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane (HMX) was the principal polynitro-organic compound measured in soils. Soils from the contaminated site decreased microbial processes and earthworm reproduction; whereas plant growth was not significantly reduced. Toxicity to aquatic organisms and genotoxicity were also assessed on soil elutriates using Microtox (Vibrio fischeri), growth inhibition of algae (Selenastrum capricornutum), and SOS Chromotest (Escherichia coli). Results indicated that soil elutriates were generally not toxic to bacteria (Microtox) and algae. However, genotoxicity was found in a number of soil elutriate samples. Thus, the explosive-contaminated soils from the antitank firing range may represent a hazard for the soil organisms. Nevertheless, the global toxicity might have partially resulted from HMX as well as from other (not identified) contaminants such as heavy metals. PMID:15223256

  12. Selective leaching of uranium from uranium-contaminated soils

    SciTech Connect

    Francis, C.W.; Mattus, A.J.; Farr, L.L.; Lee, S.Y.; Elless, M.P. |


    Three soils and a sediment contaminated with uranium were used to determine the effectiveness of sodium carbonate and citric acid leaching to decontaminate or remove uranium to acceptable regulatory levels. The objective was to selectively extract uranium using a soil washing/extraction process without seriously degrading the soil`s physicochemical characteristics or generating a secondary waste form that would be difficult to manage and/or dispose of. Two of the soils were surface soils from the DOE facility formerly called the Feed Materials Production Center (FMPC) at Fernald, Ohio. One of the soils is from near the Plant 1 storage pad and the other soil was taken from near a waste incinerator used to burn low-level contaminated trash. The third soil was a surface soil from an area formally used as a landfarm for the treatment of spent oils at the Oak Ridge Y-12 Plant. The sediment sample was material sampled from a storm sewer sediment trap at the Oak Ridge Y-12 Plant. Uranium concentrations in the Fernald soils ranged from 450 to 550 {mu}g U/g of soil while the samples from the Y-12 Plant ranged from 150 to 200 {mu}g U/g of soil.

  13. Release of contaminant U(VI) from soils

    SciTech Connect

    Zheng, Zuoping; Wan, Jiamin


    The retention, mobility, and bio-availability of U(VI) incontaminated soils depend strongly on release of U(VI). Laboratory batchexperiments were performed to evaluate the factors controlling therelease of U(VI) from contaminated soil at Oak Ridge, Tennessee. We foundthat the ionic strength of the extraction solution strongly affectsrelease of U(VI). Increase in ionic strength shows a strong effect onU(VI) release as indicated by the increase in release rates andassociated release of U(VI) concentrations. We also found that the ratioof solution volume to solid mass (V/M) has a significant impact on therelease of U(VI). Increase in the V/M ratio shows a negligible effect onthe U(VI) release over a 4-day period. However, at Day 30 and Day 120,larger V/M ratios cause greater U(VI) release. The maximum U(VI)concentrations observed in the release experiments are in the range ofschoepite estimated under conditions relevant to the experiments,suggesting that schoepite solubility primarily controls the U(VI)release, but that solubilization and desorption effects cannot bedistinguished using macroscopic methods.

  14. Phytoremediation Potential of Lead-Contaminated Soil Using Tropical Grasses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The global problem concerning contamination of the environment because of human activities is increasing. Most of the environmental contaminants are chemical by-products and heavy metals such as lead (Pb). Lead released into the environment makes its way into the air, soil and water. Lead contribute...

  15. Remediation of arsenic-contaminated soils and groundwaters


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


    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.

  16. Remediation of arsenic-contaminated soils and groundwaters


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


    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.

  17. Electroosmotic flow behaviour of metal contaminated expansive soil.


    Sivapullaiah, P V; Prakash, B S Nagendra


    It is important to study the flow behaviour through soil during electrokinetic extraction of contaminants to understand their removal mechanism. The flow through the expansive soil containing montmorillonite is monitored during laboratory electrokinetic extraction of heavy metal contaminants. The permeability of soil, which increases due to the presence of contaminants, is further enhanced during electrokinetic extraction of contaminants due to osmotic permeability. The variations in flow rates through the soil while the extracting fluid is changed to dilute acetic acid (used to control the increase of pH) and EDTA solution (used to desorb the metal ions from soil) are studied. The trends of removal of contaminants vis-a-vis the changes in the flow through the soil during different phases of electrokinetic extraction are established. Chromium ions are removed by flushing of water through the soil and increased osmotic flow is beneficial. Removal of iron ions is enhanced by induced osmotic flow and desorption of ions by electrokinetic processes. PMID:17276001

  18. Vertical column hydroclassification of metal-contaminated soils.


    Williford, C W; Li, Z; Wang, Z; Bricka, R M


    The purpose of this work was to reduce soil volumes requiring aggressive treatment. A second purpose was to determine differences in separation due to distinct forms of the metal contamination and soil texture. The objectives were to apply hydroclassification and find mass and metal-contaminant distribution of four soils contaminated with heavy metals from firing ranges, a small arms incinerator, and an electroplating operation. The soils were slurried in water, sieved, and exposed to upward flowing water to separate the soil particles into four nominal size ranges. The popping furnace soil exhibited substantial lead among all particle size fractions. The firing range soils exhibited bimodal distributions. The electroplating soil exhibited a strong concentration of metals toward the <63 microm fraction. Attrition scrubbing moderately improved the enrichment of metals in several fractions. Extraction revealed the lead and chromium in the electroplating soil to be relatively immobile. These results suggest metal distributions are influenced by the different mechanisms of introduction into the soil. They also help to predict performance of processing options such as sieving hydroclassification and attrition scrubbing. PMID:10379028

  19. 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.


    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


    EPA Science Inventory

    The Acid Extraction Treatment System (AETS) reduces the concentrations and/or leachability of heavy metals in contaminated soils so the soil can be returned to the site from which it originated. he objective of the project was to determine the effectiveness and commercial viabili...


    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...

  2. Toxicity testing of trinitrotoluene-contaminated soil composts

    SciTech Connect

    Honeycutt, M.E.; McFarland, V.A.; Jarvis, A.S.


    The Mutatox{trademark} assay and earthworm acute toxicity test were employed to evaluate the efficacy of composting in reducing the toxicity of TNT-contaminated soils. The Mutatox assay is a proprietary bacterial bioluminescence test that determines the mutagenic potential of sample extracts. The earthworm acute toxicity test was chosen because it exposes the organisms to the unaltered contaminant/solid matrix. Rockeye soil, a TNT-contaminated soil collected from a military installation, was composted using two methods. This yielded five samples, Rockeye, Compost A composting. Soil extracts were prepared for Mutatox using the sonification method. Ten serial dilution samples were tested soils/artificial soil were tested in the earthworm toxicity test. In the Rockeye soil samples, a toxic response was shown in both test methods. Mutatox indicated no toxicity in Composts A and B after composting but did not show a positive mutagenic response in the lower serial dilutions. The LC50s for Compost A and B after composting in the earthworm toxicity test were 35.3% and 100%, respectively. Using Mutatox and the earthworm toxicity test together provides a sensitive means of monitoring the effectiveness of various composting techniques for remediating TNT-contaminated soils.

  3. Ethanol-enhanced bioremediation of PAH-contaminated soils

    SciTech Connect

    Lee, P.H.; Ong, S.K.; Golchin, J.


    Bioremediation of soils contaminated with polycyclic aromatic hydrocarbons (PAHs) is highly challenging because of the low solubility and strong sorption properties of PAHs to soil organic matter. Two PAH-contaminated soils from former manufactured gas plant (MGP) sites were pretreated with ethanol to enhance the bioavailability of PAH compounds. The biodegradation of various PAHs in the pretreated soils was assessed using soil slurry reactor studies. The time needed to degrade 90% of the total PAH in the pretreated soils was at least 5 days faster than soils that were not pretreated with ethanol. A distinctive advantage with the pretreatment of soils with ethanol was the enhanced removal of 4-ring compounds such as chrysene. Approximately 90% of chrysene in the ethanol-treated soils were removed within 15 days while soils without pretreatment needed more than 30 days to obtain similar removal levels. After 35 days of biotreatment in the slurry reactors, approximately 40% of benzo(a)pyrene were removed in the ethanol-treated soils while only 20% were removed in soils not pretreated with ethanol.

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

    SciTech Connect

    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.


    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...

  6. Bioremediation Techniques of Oil Contaminated Soils in Ohio

    SciTech Connect

    Hodges, David


    The objective of this project is to develop environmentally sound and cost-effective remediation techniques for crude oil contaminated soils. By providing a guidance manual to oil and gas operators, the Ohio Division of Oil and Gas regulatory authority hopes to reduce remediation costs while improving voluntary compliance with soil clean-up requirements. This shall be accomplished by conducting a series of field tests to define the optimum range for nutrient and organic enhancement to biologically remediate soils contaminated with brines and crude oil having a wide rage of viscosity.

  7. Bioremediation potential of diesel-contaminated Libyan soil.


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


    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. PMID:27479774

  8. Temperature effects on propylene glycol-contaminated soil cores

    SciTech Connect

    Davis-Hoover, W.J.; Vesper, S.J.


    The authors are examining the effect of temperature on the biodegradation of propylene glycol (PPG) in subsurface soil cores. Subsurface soils were contaminated in situ with PPG and allowed to diffuse into the soil for 30 days. The treated soil was reexposed, and intact were incubated for 30 days at temperatures ranging from 9 to 39 C in a temperature gradient incubator. At 30 days, soil moisture, soil pH, microbial activity [fluorescein diacetate (FDA) test], R2A plate counts, and plate counts of PPG degraders were studied. Although the soil moisture and pH remained relatively unchanged, the parameters of microbial activity varied rather consistently with temperature. Multiple populations or subpopulations of bacteria appear to exist between temperatures of 9 and 39 C in these soils.

  9. Bioremediation of an oil-contaminated soil by fungal intervention

    SciTech Connect

    McGugan, B.R.; Lees, Z.M.; Senior, E.


    The central aim of this study was to determine if indigenous fungal species present in an oil-contaminated soil are capable of bioremediating the contamination. Some of the contamination has been present at a disused oil-recycling plant site for over two decades, and it was felt that the indigenous microbial species should have been subjected to specific selection pressure for a protracted period, thus effecting key enzymatic capabilities for degradation in situ. Two experimental approaches to a landfarming type or remediation were examined. The first involved a simple biostimulation process of soil fungi. The second incorporated an extensive isolation and screening program with subsequent bulking and reinoculation into the contaminated soil.

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


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


    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. PMID:22439580

  11. Effect of biodegradable amendments on uranium solubility in contaminated soils.


    Duquène, L; Tack, F; Meers, E; Baeten, J; Wannijn, J; Vandenhove, H


    Chelate-assisted phytoextraction has been proposed as a potential tool for phytoremediation of U contaminated sites. In this context, the effects of five biodegradable amendments on U release in contaminated soils were evaluated. Three soils were involved in this study, one with a relatively high background level of U, and two which were contaminated with U from industrial effluents. Soils were treated with 5 mmol kg(-1) dry weight of either citric acid, NH(4)-citrate/citric acid, oxalic acid, S,S-ethylenediamine disuccinic acid or nitrilotriacetic acid. Soil solution concentration of U was monitored during 2 weeks. All amendments increased U concentration in soil solution, but citric acid and NH(4)-citrate/citric acid mixture were most effective, with up to 479-fold increase. For oxalic acid, S,S-ethylenediamine disuccinic acid and nitrilotriacetic acid, the increase ranged from 10-to 100-fold. The highest concentrations were observed 1 to 7 days after treatment, after which U levels in soil solution gradually decreased. All amendments induced a temporary increase of soil solution pH and TOC that could not be correlated with the release of U in the soil solution. Thermodynamic stability constants (log K) of complexes did not predict the relative efficiency of the selected biodegradable amendments on U release in soil solution. Amendments efficiency was better predicted by the relative affinity of the chelate for Fe compared to U. PMID:18061243

  12. Chemical oxidation of hexachlorocyclohexanes (HCHs) in contaminated soils.


    Usman, M; Tascone, O; Faure, P; Hanna, K


    Chemical oxidation of hexachlorocyclohexanes (HCHs) was evaluated in (i) artificially spiked sand with HCH isomers (α, β, γ and δ) and (ii) contaminated soil sampled from a former gravel pit backfilled with wastes of lindane (γ-HCH). Following oxidation treatments were employed: hydrogen peroxide alone (HP), hydrogen peroxide with soluble Fe(II) (Fenton-F), sodium persulfate alone (PS), Fe(II) activated persulfate (AP) and permanganate (PM). GC-MS results revealed a significant degradation of all isomers in spiked soil in the order: F>PS>AP>HP>PM. Soluble Fe(II) enhanced the efficiency of H2O2 but decreased the reactivity of persulfate. Similar trend was observed in contaminated soil, but with less degradation probably caused by scavenging effect of organic matter and soil minerals and/or pollutant unavailability. No significant increase in oxidation efficiency was observed after using availability-enhancement agents in contaminated soil. Other limitation factors (oxidant dose, pH, catalyst type etc.) were also addressed. Among all the isomers tested, β-HCH was the most recalcitrant one which could be explained by higher metabolic and chemical stability. No by-products were observed by GC-MS regardless of the oxidant used. For being the premier study reporting chemical oxidation of HCH isomers in contaminated soils, it will serve as a base for in-situ treatments of sites contaminated by HCH isomers and other persistent organic pollutants. PMID:24486498

  13. Clean-up criteria for remediation of contaminated soils

    SciTech Connect

    Nguyen, H.D.; Wilson, J.R.; Sato, Chikashi


    {open_quotes}How clean is clean?{close_quotes} is a question commonly raised in the remediation of contaminated soils. To help with the answer, criteria are proposed to serve as guidelines for remedial actions and to define a clean-up level such that the remaining contaminant residuals in the soil will not violate the Drinking Water Standards (DWS). The equations for computing those criteria are developed from the principle of conservation of mass and are functions of the maximum concentration level in the water (MCL) and the sorption coefficient. A multiplier, ranging from 10 to 1000, is also factored into the soil standard equation to reflect the effectiveness of various remediation techniques. Maximum allowable concentration in the soil (MSCL) is presented for several contaminants which are being regulated at the present time. Future modifications are recommended for better estimates of the MSCLs as additional transport mechanisms are incorporated to account for other potentially dominant effects.

  14. Chemical contamination and transformation of soils in hydrocarbon production regions

    NASA Astrophysics Data System (ADS)

    Zamotaev, I. V.; Ivanov, I. V.; Mikheev, P. V.; Nikonova, A. N.


    The current concepts of soil pollution and transformation in the regions of hydrocarbon production have been reviewed. The development of an oil field creates extreme conditions for pedogenesis. Tendencies in the radial migration, spatial distribution, metabolism, and accumulation of pollutants (oil, oil products, and attendant heavy metals) in soils of different bioclimatic zones have been analyzed. The radial and lateral mobility of pollution halos is a universal tendency in the technogenic transformation of soils and soil cover in the regions of hydrocarbon production. The biodegradation time of different hydrocarbon compounds strongly varies under different landscape conditions, from several months to several tens of years. The transformation of original (mineral and organic) soils to their technogenic modifications (mechanically disturbed, chemically contaminated, and chemo soils and chemozems) occurs in the impact zone of technogenic hydrocarbon fluxes under any physiographical conditions. The integrated use of the existing methods for the determination of the total content and qualitative composition of bituminous substances and polyaromatic hydrocarbons in combination with the chromatographic determination of normal alkanes and hydrocarbon gases, as well as innovative methods of studies, allows revealing new processes and genetic relationships in soils and studying the functioning of soils and soil cover. The study of the hydrocarbon contamination of soils is important for development of restoration measures and lays the groundwork for the ecological and hygienic regulation based on the zonation of soil and landscape resistance to different pollutants.


    EPA Science Inventory

    Solvent flushing is a potential technique for remediating a waste disposal/spill site contaminated with organic chemicals. This technique involves the injection of a solvent mixture (e.g., water plus alcohols) that enhances contaminant solubility, reduces the retardation factor, ...

  16. Metagenomic analysis of microbial community in uranium-contaminated soil.


    Yan, Xun; Luo, Xuegang; Zhao, Min


    Uranium tailing is a serious pollution challenge for the environment. Based on metagenomic sequencing analysis, we explored the functional and structural diversity of the microbial community in six soil samples taken at different soil depths from uranium-contaminated and uncontaminated areas. Kyoto Encyclopedia of Genes and Genomes Orthology (KO) groups were obtained using a Basic Local Alignment Search Tool search based on the universal protein resource database. The KO-pathway network was then constructed using the selected KOs. Finally, alpha and beta diversity analyses were performed to explore the differences in soil bacterial diversity between the radioactive soil and uncontaminated soil. In total, 30-68 million high-quality reads were obtained. Sequence assembly yielded 286,615 contigs; and these contigs mostly annotated to 1699 KOs. The KO distributions were similar among the six soil samples. Moreover, the proportion of the metabolism of other amino acids (e.g., beta-alanine, taurine, and hypotaurine) and signal transduction was significantly lower in radioactive soil than in uncontaminated soil, whereas the proportion of membrane transport and carbohydrate metabolism was higher. Additionally, KOs were mostly enriched in ATP-binding cassette transporters and two-component systems. According to diversity analyses, Actinobacteria and Proteobacteria were the dominant phyla in radioactive and uncontaminated soil, and Robiginitalea, Microlunatus, and Alicyclobacillus were the dominant genera in radioactive soil. Taken together, these results demonstrate that soil microbial community, structure, and functions show significant changes in uranium-contaminated soil. The dominant categories such as Actinobacteria and Proteobacteria may be applied in environmental governance for uranium-contaminated soil in southern China. PMID:26433967

  17. Soil biogeochemistry, plant physiology and phytoremediation of cadmium contaminated soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cadmium (Cd) loading in soil and the environment has been accelerated worldwide due to enhanced industrialization and intensified agricultural production, particularly in the developing countries. Soil Cd pollution, resulting from both anthropogenic and geogenic sources, has posed an increasing chal...

  18. Solubility measurement of uranium in uranium-contaminated soils

    SciTech Connect

    Lee, S.Y.; Elless, M.; Hoffman, F.


    A short-term equilibration study involving two uranium-contaminated soils at the Fernald site was conducted as part of the In Situ Remediation Integrated Program. The goal of this study is to predict the behavior of uranium during on-site remediation of these soils. Geochemical modeling was performed on the aqueous species dissolved from these soils following the equilibration study to predict the on-site uranium leaching and transport processes. The soluble levels of total uranium, calcium, magnesium, and carbonate increased continually for the first four weeks. After the first four weeks, these components either reached a steady-state equilibrium or continued linearity throughout the study. Aluminum, potassium, and iron, reached a steady-state concentration within three days. Silica levels approximated the predicted solubility of quartz throughout the study. A much higher level of dissolved uranium was observed in the soil contaminated from spillage of uranium-laden solvents and process effluents than in the soil contaminated from settling of airborne uranium particles ejected from the nearby incinerator. The high levels observed for soluble calcium, magnesium, and bicarbonate are probably the result of magnesium and/or calcium carbonate minerals dissolving in these soils. Geochemical modeling confirms that the uranyl-carbonate complexes are the most stable and dominant in these solutions. The use of carbonate minerals on these soils for erosion control and road construction activities contributes to the leaching of uranium from contaminated soil particles. Dissolved carbonates promote uranium solubility, forming highly mobile anionic species. Mobile uranium species are contaminating the groundwater underlying these soils. The development of a site-specific remediation technology is urgently needed for the FEMP site.


    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...


    EPA Science Inventory

    Soil and debris from Superfund sites must be treated to minimize their threat to human health and the environment as part of remedial actions at such sites. Studies were conducted on the effectiveness with which five treatment processes removed or immobilized synthetic soils cont...

  1. Biochar: an effective amendment for remediating contaminated soil.


    Kong, Lu-Lu; Liu, Wei-Tao; Zhou, Qi-Xing


    Biochar is a carbon-rich material derived from incomplete combustion of biomass.Applying biochar as an amendment to treat contaminated soils is receiving increasing attention, and is a promising way to improve soil quality. Heavy metals are persistent and are not environmentally biodegradable. However, they can be stabilized in soil by adding biochar. Moreover, biochar is considered to be a predominant sorptive agent for organic pollutants, having a removal efficiency of about 1 order of magnitude higher than does soil/sediment organic matter or their precursor substances alone.When trying to stabilize organic and inorganic pollutants in soil, several features of biochar' s sorption capacity should be considered, viz., the nature of the pollutants to be remediated, how the biochar is prepared, and the complexity of the soil systemin which biochar may be used. In addition, a significant portion of the biochar or some of its components that are used to remediate soils do change over time through abiotic oxidation and microbial decomposition. This change process is commonly referred to as "aging:" Biochar "aging" in nature is inevitable, and aged biochar exhibits an effect that is totally different than non-aged biochar on stabilizing heavy metals and organic contaminants in soils.Studies that have been performed to date on the use of biochar to remediate contaminated soil are insufficient to allow its use for wide-scale field application.Therefore, considerable new data are necessary to expand both our understanding of how biochar performs in the field, and where it can be best used in the future for soil remediation. For example, how biochar and soil biota (microbial and faunal communities)interact in soils is still poorly understood. Moreover, studies are needed on how to best remove new species of heavy metals, and on how biochar aging affects sorption capacity are also needed. PMID:24162093


    EPA Science Inventory

    The U.S. Environmental Protection Agency's Office of Research and Development (ORD) is examining processes for remedial action at Superfund sites, and corrective action at operating disposal sites. ecent legislation emphasizes destruction and detoxification of contaminants, rathe...

  3. Use of passive sampling devices to determine soil contaminant concentrations

    SciTech Connect

    Johnson, K.A. |; Hooper, M.J.; Weisskopf, C.P.


    The effective remediation of contaminated sites requires accurate identification of chemical distributions. A rapid sampling method using passive sampling devices (PSDs) can provide a thorough site assessment. We have been pursuing their application in terrestrial systems and have found that they increase the ease and speed of analysis, decrease solvent usage and overall cost, and minimize the transport of contaminated soils. Time and cost savings allow a higher sampling frequency than is generally the case using traditional methods. PSDs have been used in the field in soils of varying physical properties and have been successful in estimating soil concentrations ranging from 1 {mu}g/kg (parts per billion) to greater than 200 mg/kg (parts per million). They were also helpful in identifying hot spots within the sites. Passive sampling devices show extreme promise as an analytical tool to rapidly characterize contaminant distributions in soil. There are substantial time and cost savings in laboratory personnel and supplies. By selectively excluding common interferences that require sample cleanup, PSDs can be retrieved from the field and processed rapidly (one technician can process approximately 90 PSDs in an 8-h work day). The results of our studies indicate that PSDs can be used to accurately estimate soil contaminant concentrations and provide lower detection limits. Further, time and cost savings will allow a more thorough and detailed characterization of contaminant distributions. 13 refs., 4 figs., 2 tabs.

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

    NASA Technical Reports Server (NTRS)

    Kushner, Len


    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.

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


    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


    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. PMID:26551220

  6. Innovative treatment for TCE-contaminated saturated clay soils

    SciTech Connect

    West, O.R.; Cameron, P.A.; Smuin, D.R.


    This paper describes the evaluation of mixed region vapor stripping (MRVS) coupled with calcium oxide conditioning for removing trichloroethylene (TCE) for a site underlain by saturated clay soils. Volatile organic compound removal during MRVS with and without calcium oxide conditioning were simulated using a previously developed model. The results of the modeling were compared with laboratory MRVS tests on undisturbed soil cores taken from the study site. The modeling results were consistent with laboratory simulations of MRVS on field-contaminated soils from the study site, and showed that calcium oxide conditioning is an effective method for enhancing VOC removal efficiencies in saturated clay soils.

  7. Release of polyaromatic hydrocarbons from coal tar contaminated soils

    SciTech Connect

    Priddy, N.D.; Lee, L.S.


    A variety of process wastes generated from manufactured gas production (MGP) have contaminated soils and groundwater at production and disposal sites. Coal tar, consisting of a complex mixture of hydrocarbons present as a nonaqueous phase liquid, makes up a large portion of MGP wastes. Of the compounds in coal tar, polyaromatic hydrocarbons (PAHs) are the major constituents of environmental concern due to their potential mutagenic and carcinogenic hazards. Characterization of the release of PAHs from the waste-soil matrix is essential to quantifying long-term environmental impacts in soils and groundwater. Currently, conservative estimates for the release of PAHs to the groundwater are made assuming equilibrium conditions and using relationships derived from artificially contaminated soils. Preliminary work suggests that aged coal tar contaminated soils have much lower rates of desorption and a greater affinity for retaining organic contaminants. To obtain better estimates of desorption rates, the release of PAHs from a coal tar soil was investigated using a flow-interruption, miscible displacement technique. Methanol/water solutions were employed to enhance PAH concentrations above limits of detection. For each methanol/water solution employed, a series of flow interrupts of varying times was invoked. Release rates from each methanol/water solution were estimated from the increase in concentration with duration of flow interruption. Aqueous-phase release rates were then estimated by extrapolation using a log-linear cosolvency model.

  8. 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.


    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.


    SciTech Connect

    Hoeffner, S. L.; Navratil, J. D.; Torrao, G.; Smalley, R.


    Soils contaminated with radionuclides are an environmental concern at most Department of Energy (DOE) sites. Clean up efforts at many of these sites are ongoing using conventional remediation techniques. These remediation techniques are often expensive and may not achieve desired soil volume reduction. Several studies using alternative remediation techniques have been performed on plutonium-contaminated soils from the Nevada Test Site. Results to date exhibit less than encouraging results, but these processes were often not fully optimized, and other approaches are possible. Clemson University and teaming partner Waste Policy Institute, through a cooperative agreement with the National Environmental Technologies Laboratory, are assisting the Nevada Test Site (NTS) in re-evaluating technologies that have the potential of reducing the volume of plutonium contaminated soil. This efforts includes (1) a through literature review and summary of (a) NTS soil characterization and (b) volume reduction treatment technologies applied to plutonium-contaminated NTS soils, (2) an interactive workshop for vendors, representatives from DOE sites and end-users, and (3) bench scale demonstration of applicable vendor technologies at the Clemson Environmental Technologies Laboratory.

  10. Soil contamination by petroleum products. Southern Algerian case

    NASA Astrophysics Data System (ADS)

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


    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.

  11. Field demonstration of soil slurry bioreactor technology for the remediation of explosives-contaminated soils

    SciTech Connect

    Hampton, M.L.; Sisk, W.E.


    The past production and handling of conventional munitions has resulted in explosives contamination of the soils at various military facilities. The principal explosive contaminants are trinitrotoluene (TNT), cyclotrimethylenetrinitramine (RDX), and cyclotetramethylenetetranitramine (HMX). Depending on the concentrations present, these explosives-contaminated soils pose both a reactivity and toxicity hazard and the potential for groundwater contamination. Bioremediation technologies are currently being developed by the U.S. Army Environmental Center as cost-effective alternatives to the current proven technology, high temperature incineration. A technology which is gaining popularity in the remediation industry is the use of soil slurry biodegradation systems in which an aqueous slurry is created by combining soils or sludge with water. Previous studies using soils contaminated with explosives from Joliet Army Ammunition Plant (JAAP) demonstrated the feasibility of this technology. A field demonstration to determine the feasibility of using Soil Slurry Sequencing Batch Reactors (SS-SBRs) to treat explosives-contaminated soils is being conducted at JAAP. Key factors to be investigated include the percent reduction of explosives and the identification of degradation products. In addition, the efficiency of reactor operations using different soil replacement volumes will be examined.

  12. Risk-based ecological soil quality criteria for the characterization of contaminated soils. Combination of chemical and biological tools.


    Fernández, María Dolores; Vega, María Milagrosa; Tarazona, José Vicente


    This paper describes the development of soil quality criteria for the characterization of soils focused on the potential risk to the ecosystem. The approach combines both Generic Soil Quality standards (GSQs) for individual chemicals and direct ecotoxicity assays on soil samples taken from the site. Criteria establish three main risk levels with their corresponding trigger values. The trigger values to determine high risk or "polluted" soils are exclusively based on direct toxicity assessments. The trigger values for the other categories are established by a combination of the application of GSQs and the results of bioassays. Low-risk is assumed when no toxicity is observed and GSQs based on precautionary ecotoxicity thresholds are not exceeded; high-risk must be considered if acute toxicity above the proposed trigger value is observed in soil or leachate samples. In between these levels, the risk cannot be elucidated and a site-specific assessment is required. The GSQs take into account the current or future land use, thus defining three categories: industrial soils, urban/residential soils and natural/agricultural/forest soils, each of them with different ecological requirements. The GSQ values are established following an inverse risk assessment methodology, integrating ecotoxicity and exposure models and setting the soil levels associated to pre-established criteria for the assumption of low risk. The proposed methodology covers all relevant ecological receptors and processes, soil organisms, potential contamination of ground and surface waters, and exposure of terrestrial vertebrates due to bioaccumulation and biomagnification. Exposure routes and protection criteria are defined in each protection goal. The relevance of each receptor and route is established according to the land use. PMID:16574196

  13. Sustainable remediation of mercury contaminated soils by thermal desorption.


    Sierra, María J; Millán, Rocio; López, Félix A; Alguacil, Francisco J; Cañadas, Inmaculada


    Mercury soil contamination is an important environmental problem that needs the development of sustainable and efficient decontamination strategies. This work is focused on the application of a remediation technique that maintains soil ecological and environmental services to the extent possible as well as search for alternative sustainable land uses. Controlled thermal desorption using a solar furnace at pilot scale was applied to different types of soils, stablishing the temperature necessary to assure the functionality of these soils and avoid the Hg exchange to the other environmental compartments. Soil mercury content evolution (total, soluble, and exchangeable) as temperature increases and induced changes in selected soil quality indicators are studied and assessed. On total Hg, the temperature at which it is reduced until acceptable levels depends on the intended soil use and on how restrictive are the regulations. For commercial, residential, or industrial uses, soil samples should be heated to temperatures higher than 280 °C, at which more than 80 % of the total Hg is released, reaching the established legal total Hg level and avoiding eventual risks derived from high available Hg concentrations. For agricultural use or soil natural preservation, conversely, maintenance of acceptable levels of soil quality limit heating temperatures, and additional treatments must be considered to reduce available Hg. Besides total Hg concentration in soils, available Hg should be considered to make final decisions on remediation treatments and potential future uses. Graphical Abstract Solar energy use for remediation of soils affected by mercury. PMID:26545893

  14. Evaluation of electrokinetic remediation of arsenic-contaminated soils.


    Kim, Soon-Oh; Kim, Won-Seok; Kim, Kyoung-Woong


    The potential of electrokinetic (EK) remediation technology has been successfully demonstrated for the remediation of heavy metal-contaminated fine-grained soils through laboratory scale and field application studies. Arsenic contamination in soil is a serious problem affecting both site use and groundwater quality. The EK technology was evaluated for the removal of arsenic from two soil samples; a kaolinite soil artificially contaminated with arsenic and an arsenic-bearing tailing-soil taken from the Myungbong (MB) gold mine area. The effectiveness of enhancing agents was investigated using three different types of cathodic electrolytes; deionized water (DIW), potassium phosphate (KH(2)PO(4)) and sodium hydroxide (NaOH). The results of the experiments on the kaolinite show that the potassium phosphate was the most effective in extracting arsenic, probably due to anion exchange of arsenic species by phosphate. On the other hand, the sodium hydroxide seemed to be the most efficient in removing arsenic from the tailing-soil. This result may be explained by the fact that the sodium hydroxide increased the soil pH and accelerated ionic migration of arsenic species through the desorption of arsenic species as well as the dissolution of arsenic-bearing minerals. PMID:16237600

  15. Preliminary Experimental Analysis of Soil Stabilizers for Contamination Control

    SciTech Connect

    Lagos, L.; Varona, J.; Zidan, A.; Gudavalli, R.; Wu, Kuang-His


    A major focus of Department of Energy's (DOE's) environmental management mission at the Hanford site involves characterizing and remediating contaminated soil and groundwater; stabilizing contaminated soil; remediating disposal sites; decontaminating and decommissioning structures, and demolishing former plutonium production process buildings, nuclear reactors, and separation plants; maintaining inactive waste sites; transitioning facilities into the surveillance and maintenance program; and mitigating effects to biological and cultural resources from site development and environmental cleanup and restoration activities. For example, a total of 470,914 metric tons of contaminated soil from 100 Areas remediation activities were disposed at the Environmental Restoration Disposal Facility (ERDF) during 2004. The Applied Research Center (ARC) at Florida International University (FIU) is supporting the Hanford's site remediation program by analyzing the effectiveness of several soil stabilizers (fixatives) for contamination control during excavation activities. The study is focusing on determining the effects of varying soil conditions, temperature, humidity and wind velocity on the effectiveness of the candidate stabilizers. The test matrix consists of a soil penetration-depth study, wind tunnel experiments for determination of threshold velocity, and temperature and moisture-controlled drying/curing experiments. These three set of experiments are designed to verify performance metrics, as well as provide insight into what fundamental forces are altered by the use of the stabilizer. This paper only presents the preliminary results obtained during wind tunnel experiments using dry Hanford soil samples (with 2.7% moisture by weight). These dry soil samples were exposed to varying wind speeds from 2.22 m/sec to 8.88 m/sec. Furthermore, airborne particulate data was collected for the dry Hanford soil experiments using an aerosol analyzer instrument. (authors)

  16. Magnetic mineralogy of heavy metals-contaminated soils

    NASA Astrophysics Data System (ADS)

    Shenggao, L.


    Soils around mine and in urban areas are often contaminated by heavy metals derived from industrial and human activities [1, 2]. These contaminated soils are often characterized by a magnetic enhancement on topsoils. Many studies demonstrated that there are significant correlations between heavy metals and various magnetic parameters in contaminated soils, indicating a strong affinity of heavy metals to magnetic minerals. The magnetic particles in contaminated soils were separated by a magnetic separation technique. The rock magnetism, XRD, field emission scanning electron microscopy equiped with an energy-dispersive X-ray analyzer (FESEM/EDX) were used to characterize their magnetic mineralogy. Results of XRD analysis indicated that the magnetic particles separated from heavy metal-contaminated soils are composed of quartz, magnetite, and hematite. Based on the X-ray diffraction peak intensity, the Fe3O4 was identified as the predominant magnetic mineral phase. The high-temperature magnetization (Ms-T) curves of magnetic particles extracted from contaminated soils show a sharp Ms decrease at about 580C (the Curie temperature of magnetite), suggesting that magnetite is the dominant magnetic carrier. The hysteresis loops of contaminated soils are closed at about 100-200 mT which is consistent with the presence of a dominant ferrimagnetic mineral phase. The FESEM analysis showed a great variety of shapes of magnetic particles in contaminated soils. The most common morphology are observed in the form of spherules, with the sizes ranging from 20 to 100 um. The chemical composition of magnetic particles consist mainly of Fe, Si, Al, and Ca with minor heavy metal elements (Cu, Zn, Hg, and Cr). The semi-quantitative Fe content identified by FESEM/EDX ranged from 40 to 90%. Combined studies of rock magnetism, XRD, and FESEM/EDX indicated that magnetic mineral phases responsible for the magnetic enhancement of contaminated soils are anthropogenic origin which are coarse

  17. In situ bioremediation of contaminated unsaturated subsurface soils

    SciTech Connect

    Sims, J.L.; Sims, R.C.; Dupont, R.R.; Matthews, J.E.; Russell, H.H.


    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 the utilization of these systems, are issues which have been identified by the Regional Superfund Engineering Forum as concerns of Superfund decision makers. Although in situ bioremediation has been used for a number of years in the restoration of ground water contaminated by petroleum hydrocarbons, it has only been in recent years that in situ systems have been directed toward contaminants in unsaturated subsurface soils. Research has contributed greatly to understanding the biotic, chemical, and hydrologic parameters which contribute to or restrict the application of in-situ bioremediation and has been successful at a number of locations in demonstrating its effectiveness at field scale.

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


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


    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. PMID:26298343

  19. Contamination of Austrian soil with caesium-137.


    Bossew, P; Ditto, M; Falkner, T; Henrich, E; Kienzl, K; Rappelsberger, U


    Austria ranks among the countries that have been most strongly affected by the Chernobyl fallout. The mean contamination with 137Cs is 21.0 kBq/m2, of which 18.7 kBq/m2 is due to the Chernobyl accident, whereas global fallout contributes 2.3 kBq/m2. Maximum values of total 137Cs contamination are nearly 200 kBq/m2. Total deposition of Chernobyl 137Cs on Austrian territory is 1.6 PBq or a fraction of around 2% of the 137Cs released from the reactor. 2115 measurements were used to draw the Austrian "caesium map". The geographical pattern of fallout distribution shows regional differences of contamination as high as 1:100. PMID:11398378

  20. Contaminant bioavailability in soils, sediments, and aquatic environments

    PubMed Central

    Traina, Samuel J.; Laperche, Valérie


    The aqueous concentrations of heavy metals in soils, sediments, and aquatic environments frequently are controlled by the dissolution and precipitation of discrete mineral phases. Contaminant uptake by organisms as well as contaminant transport in natural systems typically occurs through the solution phase. Thus, the thermodynamic solubility of contaminant-containing minerals in these environments can directly influence the chemical reactivity, transport, and ecotoxicity of their constituent ions. In many cases, Pb-contaminated soils and sediments contain the minerals anglesite (PbSO4), cerussite (PbCO3), and various lead oxides (e.g., litharge, PbO) as well as Pb2+ adsorbed to Fe and Mn (hydr)oxides. Whereas adsorbed Pb can be comparatively inert, the lead oxides, sulfates, and carbonates are all highly soluble in acidic to circumneutral environments, and soil Pb in these forms can pose a significant environmental risk. In contrast, the lead phosphates [e.g., pyromorphite, Pb5(PO4)3Cl] are much less soluble and geochemically stable over a wide pH range. Application of soluble or solid-phase phosphates (i.e., apatites) to contaminated soils and sediments induces the dissolution of the “native” Pb minerals, the desorption of Pb adsorbed by hydrous metal oxides, and the subsequent formation of pyromorphites in situ. This process results in decreases in the chemical lability and bioavailability of the Pb without its removal from the contaminated media. This and analogous approaches may be useful strategies for remediating contaminated soils and sediments. PMID:10097045

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

    SciTech Connect

    Mrdakovic Popic, Jelena; Stojanovic, Mirjana; Milosevic, Sinisa; Iles, Deana; Zildzovic, Snezana


    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 uranium 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)

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

    PubMed Central

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


    Background Chemical contaminants in the Canadian subarctic present a health risk with exposures primarily occurring via the food consumption. Objective 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. Design 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. Methods 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. Results 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. Conclusion 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. PMID:26025557

  3. Extraction of pesticides from contaminated soil using supercritical carbon dioxide

    SciTech Connect

    Hunter, G.B.


    The demand for processes to clean up contaminated soils without generating additional contaminants, such as hazardous solvents, is increasing. One approach to minimizing this problem is to use supercritical fluids like light hydrocarbons and CO[sub 2] to extract contaminants from soils. Gases exhibit unique properties under supercritical conditions. They retain the ability to diffuse through the interstitial spaces of solid materials, plus they have the solvating power of liquids. Some examples of extractions using SCFs are caffeine from coffee, cholesterol from eggs, drugs from plants, and nicotine from tobacco. Supercritical CO[sub 2] is an attractive, alternative extraction medium for removal of pesticides from soils. Carbon dioxide is readily available, relatively inexpensive, and if recycled, nonpolluting. Contaminants may be easily recovered by evaporating the CO[sub 2] into an expansion vessel. Supercritical fluid extraction technology is discussed and results are given for the extraction of atrazine, bentazon, alachlor, and permethrin from contaminated soil prepared in the laboratory. Initial studies show >95% removal for these pesticides.

  4. Extraction of pesticides from contaminated soil using supercritical carbon dioxide

    SciTech Connect

    Hunter, G.B.


    The demand for processes to clean up contaminated soils without generating additional contaminants, such as hazardous solvents, is increasing. One approach to minimizing this problem is to use supercritical fluids like light hydrocarbons and CO{sub 2} to extract contaminants from soils. Gases exhibit unique properties under supercritical conditions. They retain the ability to diffuse through the interstitial spaces of solid materials, plus they have the solvating power of liquids. Some examples of extractions using SCFs are caffeine from coffee, cholesterol from eggs, drugs from plants, and nicotine from tobacco. Supercritical CO{sub 2} is an attractive, alternative extraction medium for removal of pesticides from soils. Carbon dioxide is readily available, relatively inexpensive, and if recycled, nonpolluting. Contaminants may be easily recovered by evaporating the CO{sub 2} into an expansion vessel. Supercritical fluid extraction technology is discussed and results are given for the extraction of atrazine, bentazon, alachlor, and permethrin from contaminated soil prepared in the laboratory. Initial studies show >95% removal for these pesticides.

  5. Immobilization of radioactive strontium in contaminated soils by phosphate treatment

    SciTech Connect

    Kim, K.H.; Ammons, J.T. . Dept. of Plant and Soil Science); Lee, S.Y. )


    The feasibility of in situ phosphate- and metal- (calcium, aluminum, and iron) solution treatment for {sup 90}Sr immobilization was investigated. Batch and column experiments were performed to find optimum conditions for coprecipitation of {sup 90}Sr with Ca-, Al-, and Fe-phosphate compounds in contaminated soils. Separate columns were packed with artificially {sup 85}Sr-contaminated acid soil as well as {sup 90}Sr-contaminated soil from the Oak Ridge Reservation. After metal-phosphate treatment, the columns were then leached successively with either tapwater or 0.001 M CaCl{sub 2} solution. Most of the {sup 85}Sr coprecipitated with the metal phosphate compounds. Immobilization of {sup 85}Sr and {sup 90}Sr was affected by such factors as solution pH, metal and phosphate concentration, metal-to-phosphate ratio, and soil characteristics. Equilibration time after treatments also affected {sup 85}Sr immobilization. Many technology aspects still need to be investigated before field applications are feasible, but these experiments indicate that phosphate-based in situ immobilization should prevent groundwater contamination and will be useful as a treatment technology for {sup 90}Sr-contaminated sites. 15 refs., 3 figs., 1 tab.

  6. Arsenic biotransformation in earthworms from contaminated soils.


    Button, Mark; Jenkin, Gawen R T; Harrington, Chris F; Watts, Michael J


    Two species of arsenic (As) resistant earthworm, Lumbricus rubellus and Dendrodrillus rubidus, their host soils and soil excretions (casts) were collected from 23 locations at a former As mine in Devon, UK. Total As concentrations, measured by ICP-MS, ranged from 255 to 13,080 mg kg(-1) in soils, 11 to 877 mg kg(-1) in earthworms and 284 to 4221 mg kg(-1) in earthworm casts from a sub-sample of 10 of the 23 investigated sites. The samples were also measured for As speciation using HPLC-ICP-MS to investigate potential As biotransformation pathways. Inorganic arsenate (As(V)) and arsenite (As(III)) were the only species detected in the soil. As(V) and As(III) were also the dominant species found in the earthworms and cast material together with lower proportions of the organic species methylarsonate (MA(V)), dimethylarsinate (DMA(V)), arsenobetaine (AB) and three arsenosugars. Whilst the inorganic As content of the earthworms increased with increasing As body burden, the concentration of organic species remained relatively constant. These results suggest that the biotransformation of inorganic arsenic to organic species does not contribute to As resistance in the sampled earthworm populations. Quantification of As speciation in the soil, earthworms and cast material allows a more comprehensive pathway for the formation of AB in earthworms to be elucidated. PMID:19657532

  7. Magnetic susceptibility properties of pesticide contaminated volcanic soil

    NASA Astrophysics Data System (ADS)

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


    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.

  8. Extraction of copper in a contaminated soil onto chabazite

    NASA Astrophysics Data System (ADS)

    Liao, P.-H.; Wang, H. Paul; Hsiao, M.-C.; Eyring, Edward M.; Huang, C.-H.; Jou, C.-J. G.


    Copper in a contaminated soil nearby a printed-circuit board waste recycling plant has been extracted onto a microporous molecular sieve (chabazite). The chabazite supported CuO can be used as a chemical looping combustion (CLC) oxygen carrier for CO2 capture. Speciation of copper in the contaminated soil and on the chabazite during CLC has been studied by X-ray absorption near edge structure (XANES) and X-ray absorption fine structure (EXAFS) spectroscopy. By XANES, it is found that about 90% of copper (mainly Cu2+) in the contaminated soil can be extracted and adsorbed on the chabazite, in which CuO can be formed on the chabazite after calcination at 773 K for two hours. The EXAFS data show that copper in the soil and chabazite possesses Cu-O bond distances of 1.96 and 1.95 Å, respectively and coordination numbers (CNs) of 1-3. After CLC, CuO on chabazite has been reduced to Cu with a C-C bond distance of 2.4 Å and a CN of 8. This work also exemplifies the utilization of EXAFS and XANES to reveal the migration path of copper between a contaminated soil and a molecular sieve and interconversion of Cu-CuO in the CLC process.

  9. Chemical and toxicological testing of composted explosives-contaminating soil

    SciTech Connect

    Griest, W.H.; Steward, A.J.; Tyndall, R.L.; Caton, J.E.; Ho, C.H.; Ironside, K.S.; Caldwell, W.M.; Tan, E. )


    Static-pile and mechanically stirred composts of explosives-contaminated soil at the Umatilla Army Depot Activity (UMDA, Umatilla, OR) in a field composting optimization study were characterized chemically and toxicologically. The concentrations of extractable explosives (e.g., 2,4,6-trinitrotoluene) in the composts and their aqueous leachates, the mutagenicity of organic solvent extracts from the composts, and the toxicity of compost aqueous leachates to Ceriodaphnia dubia all decreased considerably with 20 d of composting. After 44 d or 90 d of composting, the toxicity, mutagenicity, and concentrations of extractable explosives decreased more than 90% in some cases. The composting efficiency was generally inversely proportional to the percentage (v/v) of contaminated soil. Composting in static piles was efficient up to about 20% (v/v) of contaminated soil; composting in the mechanically stirred composters was efficient up to about 25% soil. Mechanical composting was more efficient than composting in static piles. The main conclusion of this study is that composting can effectively remediate explosives contaminated soil and sediment. However, low levels of explosives and metabolites, bacterial mutagenicity, and leachable toxicity to Ceriodaphnia may remain after composting. The sources of residual toxicity and mutagenicity and the ultimate fate of the explosives are unknown.

  10. Treatment of NORM contaminated soil from the oilfields.


    Abdellah, W M; Al-Masri, M S


    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. PMID:24378731

  11. Geochemistry of lead contaminated wetland soils amended with phosphorus

    NASA Astrophysics Data System (ADS)

    Strawn, Daniel G.; Hickey, Patrick; Knudsen, Andrew; Baker, Leslie


    To remediate Pb contaminated soils it is proposed that phosphorus can be amended to the soils to transform the Pb into poorly soluble Pb-phosphate mineral phases. However, remediation strategies must account for variable Pb speciation and site-specific factors. In this study soil mineralogy and Pb speciation in soils from P-amended field trials at sites within the Coeur d’Alene River Basin in Idaho, USA were investigated. The soils are contaminated from mining activities and are enriched with Fe and Mn. Selective extraction of the soils indicated that the Fe oxides are poorly crystalline. XRD of the soil clay size fractions identified quartz, muscovite, kaolinite, siderite, lepidocrocite, and chlorite minerals. Amendment with P fertilizer dissolved the siderite. No Pb-phosphate minerals were detected by XRD. Electron microprobe analysis showed direct correlations between Pb, Fe, and Mn in the unamended soils, and negative correlations between Pb and Si. Lead and Mn were strongly correlated. In the amended soils Fe and P were strongly correlated. Results indicate that the Pb is associated with poorly crystalline Fe and Mn oxides, and that added P is primarily associated with Fe oxide phases. Comparisons of pore water Pb concentrations with chloropyromorphite and plumbogummite solubility suggest that in the phosphate-amended soils the pore waters are undersaturated in these phases, whereas several of the control soil pore waters were oversaturated, indicating the added phosphate suppressed the Pb solubility. Results from this research provide insight into the geochemistry occurring in the P-remediated soils that will help in making management and remediation decisions.

  12. Vitrification testing of soil fines from contaminated Hanford 100 Area and 300 Area soils

    SciTech Connect

    Ludowise, J.D.


    The suitability of Hanford soil for vitrification is well known and has been demonstrated extensively in other work. The tests reported here were carried out to confirm the applicability of vitrification to the soil fines (a subset of the Hanford soil potentially different in composition from the bulk soil) and to provide data on the performance of actual, vitrified soil fines. It was determined that the soil fines were generally similar in composition to the bulk Hanford soil, although the fraction <0.25 mm in the 100 Area soil sample appears to differ somewhat from the bulk soil composition. The soil fines are readily melted into a homogeneous glass with the simple additions of CaO and/or Na{sub 2}O. The vitrified waste (plus additives) occupies only 60% of the volume of the initial untreated waste. Leach testing has shown the glasses made from the soil fines to be very durable relative to natural and man-made glasses and has demonstrated the ability of the vitrified waste to greatly reduce the release of radionuclides to the environment. Viscosity and electrical conductivity measurements indicate that the soil fines will be readily processable, although with levels of additives slightly greater than used in the radioactive melts. These tests demonstrate the applicability of vitrification to the contaminated soil fines and the exceptional performance of the waste form resulting from the vitrification of contaminated Hanford soils.

  13. Environmental effects of soil contamination by shale fuel oils.


    Kanarbik, Liina; Blinova, Irina; Sihtmäe, Mariliis; Künnis-Beres, Kai; Kahru, Anne


    Estonia is currently one of the leading producers of shale oils in the world. Increased production, transportation and use of shale oils entail risks of environmental contamination. This paper studies the behaviour of two shale fuel oils (SFOs)--'VKG D' and 'VKG sweet'--in different soil matrices under natural climatic conditions. Dynamics of SFOs' hydrocarbons (C10-C40), 16 PAHs, and a number of soil heterotrophic bacteria in oil-spiked soils was investigated during the long-term (1 year) outdoor experiment. In parallel, toxicity of aqueous leachates of oil-spiked soils to aquatic organisms (crustaceans Daphnia magna and Thamnocephalus platyurus and marine bacteria Vibrio fischeri) and terrestrial plants (Sinapis alba and Hordeum vulgare) was evaluated. Our data showed that in temperate climate conditions, the degradation of SFOs in the oil-contaminated soils was very slow: after 1 year of treatment, the decrease of total hydrocarbons' content in the soil did not exceed 25 %. In spite of the comparable chemical composition of the two studied SFOs, the VKG sweet posed higher hazard to the environment than the heavier fraction (VKG D) due to its higher mobility in the soil as well as higher toxicity to aquatic and terrestrial species. Our study demonstrated that the correlation between chemical parameters (such as total hydrocarbons or total PAHs) widely used for the evaluation of the soil pollution levels and corresponding toxicity to aquatic and terrestrial organisms was weak. PMID:24865504

  14. Assessment of combined electro-nanoremediation of molinate contaminated soil.


    Gomes, Helena I; Fan, Guangping; Mateus, Eduardo P; Dias-Ferreira, Celia; Ribeiro, Alexandra B


    Molinate is a pesticide widely used, both in space and time, for weed control in rice paddies. Due to its water solubility and affinity to organic matter, it is a contaminant of concern in ground and surface waters, soils and sediments. Previous works have showed that molinate can be removed from soils through electrokinetic (EK) remediation. In this work, molinate degradation by zero valent iron nanoparticles (nZVI) was tested in soils for the first time. Soil is a highly complex matrix, and pollutant partitioning between soil and water and its degradation rates in different matrices is quite challenging. A system combining nZVI and EK was also set up in order to study the nanoparticles and molinate transport, as well as molinate degradation. Results showed that molinate could be degraded by nZVI in soils, even though the process is more time demanding and degradation percentages are lower than in an aqueous solution. This shows the importance of testing contaminant degradation, not only in aqueous solutions, but also in the soil-sorbed fraction. It was also found that soil type was the most significant factor influencing iron and molinate transport. The main advantage of the simultaneous use of both methods is the molinate degradation instead of its accumulation in the catholyte. PMID:24946031

  15. In situ recycling of contaminated soil uses bioremediation

    SciTech Connect

    Shevlin, P.J.; Reel, D.A.


    OxyChem Pipeline Operations, primarily an ethylene and propylene products mover, has determined that substantial savings can be realized by adopting a bioremediation maintenance and recycling approach to hydrocarbon-contaminated soil. By this method, the soil can be recycled in situ, or in containers. To implement the soil-recycling program, OxyChem elected to use a soil remediator and natural absorbent product, Oil Snapper. This field maintenance material, based on an Enhanced Urea Technology, provides a diet to stimulate the growth of hydrocarbon-eating microbes. It works well either with indigenous soil microbes or with commercial microbes. The product is carried in field vehicles, which makes it immediately available when leaks or spills are discovered. Procedure for clean-up is to apply product and mix it into affected soil. Thus the contaminant is contained, preventing further migration; the contaminant is dispersed throughout the product, making it more accessible to the microbes; nutrients are immediately available to the microbes; and the material contributes aeration and moisture-retention properties.

  16. Application of Ultrasonic for Decontamination of Contaminated Soil - 13142

    SciTech Connect

    Vasilyev, A.P.; Lebedev, N.M.; Savkin, A.E.


    The trials of soil decontamination were carried out with the help of a pilot ultrasonic installation in different modes. The installation included a decontamination bath equipped with ultrasonic sources, a precipitator for solution purification from small particles (less than 80 micrometer), sorption filter for solution purification from radionuclides washing out from soil, a tank for decontamination solution, a pump for decontamination solution supply. The trials were carried out on artificially contaminated sand with specific activity of 4.5 10{sup 5} Bk/kg and really contaminated soil from Russian Scientific Center 'Kurchatovsky Institute' (RSC'KI') with specific activity of 2.9 10{sup 4} Bk/kg. It was established that application of ultrasonic intensify the process of soil reagent decontamination and increase its efficiency. The decontamination factor for the artificially contaminated soil was ∼200 and for soil from RSC'KI' ∼30. The flow-sheet diagram has been developed for the new installation as well as determined the main technological characteristics of the equipment. (authors)

  17. 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

  18. Transport of agricultural contaminants through karst soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Karst landscapes are common in many agricultural regions in the US. Well-developed karst landscapes are characterized by shallow soils, sinkholes, sinking streams, underground conduits, and springs. In these landscapes surface runoff is minimal and most recharge enters the subsurface relatively quic...

  19. Recycling Ni from Contaminated and Mineralized Soils.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rare plant species accumulate potentially valuable concentrations of some metals. Alyssum murale readily accumulates over 2% Ni in aboveground dry matter when grown on Ni-mineralized serpentine soils in Oregon, allowing production of “hay” biomass with at least 400 kg Ni ha-1 with low levels of fer...


    EPA Science Inventory

    Hydraulic fracturing is a physical process that creates fractures in silty clay soil to enhance its permeability. The technology, developed by the Risk Reduction Engineering Laboratory (RREL) and the University of Cincinnati, creates sand-filled horizontal fractures up to 1 in. i...

  1. [In situ immobilization remediation of heavy metals-contaminated soils: a review].


    Wang, Li-Qun; Luo, Lei; Ma, Yi-Bing; Wei, Dong-Pu; Hua, Luo


    In situ immobilization of heavy metals in contaminated soils by adding extraneous active amendments has been considered as a cost-effective measure for contaminated soil remediation. Application of immobilization amendments can decrease the available fractions of heavy metals or change their redox states, and thus, effectively decrease the mobility, bioavailability, and toxicity of the heavy metals in soils. This paper summarized the present researches about the in situ immobilization of heavy metals in soils, including kinds of immobilization amendments, research methods, immobilization indexes, immobilization mechanisms, and relevant environmental risk assessment. The mostly applied amendments include clay minerals, phosphates, organic composts, and microbes. Due to the complexity of soil matrix and the limitations of current analytical techniques, the exact immobilization mechanisms have not been clarified, which could include precipitation, chemical adsorption and ion exchange, surface precipitation, formation of stable complexes with organic ligands, and redox reaction. The prospects and limitations of in situ immobilization of heavy metals in soils were discussed. Future work should focus on the elucidation of immobilization mechanisms at molecular scale, with specific attention be paid to the potential risks of applying immobilization amendments and its long-term effects on field soils. PMID:19803184

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


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


    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. PMID:26109225

  3. Biological attributes of rehabilitated soils contaminated with heavy metals.


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


    This study aimed to evaluate the effects of two rehabilitation systems in sites contaminated by Zn, Cu, Pb, and Cd on biological soil attributes [microbial biomass carbon (Cmic), basal and induced respiration, enzymatic activities, microorganism plate count, and bacterial and fungal community diversity and structure by denaturing gradient gel electrophoresis (DGGE)]. These systems (S1 and S2) consisted of excavation (trenching) and replacement of contaminated soil by uncontaminated soil in rows with Eucalyptus camaldulensis planting (S1-R and S2-R), free of understory vegetation (S1-BR), or completely covered by Brachiaria decumbens (S2-BR) in between rows. A contaminated, non-rehabilitated (NR) site and two contamination-free sites [Cerrado (C) and pasture (P)] were used as controls. Cmic, densities of bacteria and actinobacteria, and enzymatic activities (β-glucosidase, acid phosphatase, and urease) were significantly higher in the rehabilitated sites of system 2 (S2-R and S2-BR). However, even under high heavy metal contents (S1-R), the rehabilitation with eucalyptus was also effective. DGGE analysis revealed similarity in the diversity and structure of bacteria and fungi communities between rehabilitated sites and C site (uncontaminated). Principal component analysis showed clustering of rehabilitated sites (S2-R and S2-BR) with contamination-free sites, and S1-R was intermediate between the most and least contaminated sites, demonstrating that the soil replacement and revegetation improved the biological condition of the soil. The attributes that most explained these clustering were bacterial density, acid phosphatase, β-glucosidase, fungal and actinobacterial densities, Cmic, and induced respiration. PMID:26662102

  4. Assessing Metal Contamination in Lead Arsenate Contaminated Orchard Soils Using Near and Mid-Infrared Diffuse Reflectance Spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Historic use of lead-arsenate as pesticide in apple orchards left many soils contaminated with arsenic (As) and lead (Pb). Notorious health effects and their severe soil contamination are of primary concerns for major regulatory agencies, and community at large. Wet chemistry methods for soil anal...

  5. Regionally contaminated aquifers--toxicological relevance and remediation options (Bitterfeld case study).


    Heidrich, Susanne; Schirmer, Mario; Weiss, Holger; Wycisk, Peter; Grossmann, Jochen; Kaschl, Arno


    Large-scale contaminated megasites like Bitterfeld in eastern Germany are characterized by a regional contamination of soil, surface water and groundwater as a result of a long and varied history of chemical production. While the contaminants in soils and sediments mostly represent a localized problem, pollutants in groundwater may spread to uncontaminated areas and endanger receptors like surface water and drinking water wells according to the site-specific hydrologic regime. From the toxicological point of view, the contaminants at the Bitterfeld megasite represent a dangerous cocktail of various harmful substances coming from a multitude of sources. Appropriate remediation techniques must be able to remedy the specific problems arising from hot spot areas within the megasite in addition to preventing a further extension of the contaminated zone towards uncontaminated compartments. Therefore, a combination of specifically designed remediation technologies based on the pump and treat-principle with in situ technologies, such as reactive walls and monitored/enhanced natural attenuation, is necessary to efficiently address the miscellaneous challenges at this megasite. In this paper, the currently known contaminant distribution, the associated problems for human health and the environment and possible remediation strategies are presented for the Bitterfeld megasite. PMID:15464625

  6. Soil Washing Experiment for Decontamination of Contaminated NPP Soil

    SciTech Connect

    Son, J.K.; Kang, K.D.; Kim, K.D.; Ha, J.H.; Song, M.J.


    The preliminary experiment was performed to obtain the operating conditions of soil washing decontamination process such as decontamination agent, decontamination temperature, decontamination time and ratio of soil and decontamination agent. To estimate decontamination efficiency, particle size of soil was classified into three categories; {>=} 2.0 mm, 2.0 {approx} 0.21 mm and {<=} 0.21 mm. Major target of this experiment was decontamination of Cs-137. The difference of decontamination efficiency using water and neutral salts as decontamination agent is not high. It is concluded that the best temperature of decontamination agent is normal temperature and the best decontamination time was about 60 minutes. And the best ratio of soil and decontamination agent is 1:10. In case of Cs decontamination for fine soils, the decontamination results using neutral salts such as Na{sub 2}CO{sub 3} and Na{sub 3}PO{sub 4} shows some limits while using strong acid such as sulfuric acid or hydrochloric acid shows high decontamination efficiency ({>=}90%). But we conclude that decontamination using strong acid is also inappropriate because of the insufficiency of decontamination efficiency for highly radioactive fine soils and the difficulty for treatment of secondary liquid waste. It is estimated that the best decontamination process is to use water as decontamination agent for particles which can be decontaminated to clearance level, after particle size separation. (authors)

  7. Biological and chemical tests of contaminated soils to determine bioavailability and environmentally acceptable endpoints (EAE)

    SciTech Connect

    Montgomery, C.R.; Menzie, C.A.; Pauwells, S.J.


    The understanding of the concept of bioavailability of soil contaminants to receptors and its use in supporting the development of EAE is growing but still incomplete. Nonetheless, there is increased awareness of the importance of such data to determine acceptable cleanup levels and achieve timely site closures. This presentation discusses a framework for biological and chemical testing of contaminated soils developed as part of a Gas Research Institute (GRI) project entitled ``Environmentally Acceptable Endpoints in Soil Using a Risk Based Approach to Contaminated Site Management Based on Bioavailability of Chemicals in Soil.`` The presentation reviews the GRI program, and summarizes the findings of the biological and chemical testing section published in the GRI report. The three primary components of the presentation are: (1) defining the concept of bioavailability within the existing risk assessment paradigm, (2) assessing the usefulness of the existing tests to measure bioavailability and test frameworks used to interpret these measurements, and (3) suggesting how a small selection of relevant tests could be incorporated into a flexible testing scheme for soils to address this issue.

  8. Phytoremediation of contaminated soils and groundwater: lessons from the field

    SciTech Connect

    Vangronsveld, J.; van der Lelie, D.; Herzig, R.; Weyens, N.; Boulet, J.; Adriaensen, K.; Ruttens, A.; Thewys, T.; Vassilev, A.; Meers, E.; Nehnevajova, E.; Mench, M.


    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 an 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).

  9. Deep soil mixing for reagent delivery and contaminant treatment

    SciTech Connect

    Korte, N.; Gardner, F.G.; Cline, S.R.; West, O.R.


    Deep soil mixing was evaluated for treating clay soils contaminated with TCE and its byproducts at the Department of Energy`s Kansas City Plant. The objective of the project was to evaluate the extent of limitations posed by the stiff, silty-clay soil. Three treatment approaches were tested. The first was vapor stripping. In contrast to previous work, however, laboratory treatability studies indicated that mixing saturated, clay soil was not efficient unless powdered lime was added. Thus, powder injection of lime was attempted in conjunction with the mixing/stripping operation. In separate treatment cells, potassium permanganate solution was mixed with the soil as a means of destroying contaminants in situ. Finally, microbial treatment was studied in a third treatment zone. The clay soil caused operational problems such as breakage of the shroud seal and frequent reagent blowouts. Nevertheless, treatment efficiencies of more than 70% were achieved in the saturated zone with chemical oxidation. Although expensive ($1128/yd{sup 3}), there are few alternatives for soils of this type.

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


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


    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. PMID:27127923

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


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


    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. PMID:10819205


    EPA Science Inventory

    The mechanisms by which contaminants are released from sediments/soils and absorbed into the skin are poorly understood. The project will first conduct invitro experiments to study the effects of particle layering and chemical saturation. Secondly, mechanistic models will be de...


    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. Tool samples subsurface soil free of surface contaminants

    NASA Technical Reports Server (NTRS)

    Kemmerer, W. W.; Wooley, B. C.


    Sampling device obtains pure subsurface soil that is free of any foreign substance that may exist on the surface. It is introduced through a contaminated surface area in a closed condition, opened, and a subsurface sample collected, sealed while in the subsurface position, and then withdrawn.


    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...


    EPA Science Inventory

    This document summarizes the contents of a seminar on treatment of lead-contaminated soils presented on August 28, 1990, to Region V Superfund and RCRA personnel by members of EPA's Engineering and Treatment Technology Support Center located in the Risk Reduction Engineering Labo...


    EPA Science Inventory

    This handbook comprises an update of Volume1 of the 1984 USEPA document entitled "Review of In-Place Treatment Techniques for Contaminated Surface Soils." The purpose of this handbook is the same as that of the original document - to provide state-of-the-art information on in sit...


    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...


    EPA Science Inventory

    A critical review of biological treatment processes for remediation of contaminated soils is presented. The focus of the review is on documented cost and performance of biological treatment technologies demonstrated at full- or
    field-scale. Some of the data were generated b...


    EPA Science Inventory

    The Robert S. Kerr Environmental Research Laboratory (RSKERL) has developed a number of Issue Papers and Briefing Documents which are designed to exchange up-to-date information related to the remediation of contaminated soil and ground water at hazardous waste sites. In an attem...


    EPA Science Inventory

    This report provides the results of a study that examined the quantities of explosives-contaminated soils at Army installations in the United States in order to understand the user requirements for environmental technology research and development work. This report provides a tim...

  2. Antimony release from contaminated mine soils and its migration in four typical soils using lysimeter experiments.


    Shangguan, Yu-Xian; Zhao, Long; Qin, Yusheng; Hou, Hong; Zhang, Naiming


    Antimony (Sb) can pose great risks to the environment in mining and smelting areas. The migration of Sb in contaminated mine soil was studied using lysimeter experiments. The exchangeable concentration of soil Sb decreased with artificial leaching. The concentrations of Sb retained in the subsoil layers (5-25cm deep) were the highest for Isohumosol and Ferrosol and the lowest for Sandy soil. The Sb concentrations in soil solutions decreased with soil depth, and were adequately simulated using a logarithmic function. The Sb migration pattern in Sandy soil was markedly different from the patterns in the other soils which suggested that Sb may be transported in soil colloids. Environmental factors such as water content, soil temperature, and oxidation-reduction potential of the soil had different effects on Sb migration in Sandy soil and Primosol. The high Fe and Mn contents in Ferrosol and Isohumosol significantly decreased the mobility of Sb in these soils. The Na and Sb concentrations in soils used in the experiments positively correlated with each other (P<0.01). The Sb concentrations in soil solutions, the Sb chemical fraction patterns, and the Sb/Na ratios decreased in the order Sandy soil>Primosol>Isohumosol>Ferrosol, and we concluded that the Sb mobility in the soils also decreased in that order. PMID:27395817

  3. Implications of Using Thermal Desorption to Remediate Contaminated Agricultural Soil: Physical Characteristics and Hydraulic Processes.


    O'Brien, Peter L; DeSutter, Thomas M; Casey, Francis X M; Derby, Nathan E; Wick, Abbey F


    Given the recent increase in crude oil production in regions with predominantly agricultural economies, the determination of methods that remediate oil contamination and allow for the land to return to crop production is increasingly relevant. Ex situ thermal desorption (TD) is a technique used to remediate crude oil pollution that allows for reuse of treated soil, but the properties of that treated soil are unknown. The objectives of this research were to characterize TD-treated soil and to describe implications in using TD to remediate agricultural soil. Native, noncontaminated topsoil and subsoil adjacent to an active remediation site were separately subjected to TD treatment at 350°C. Soil physical characteristics and hydraulic processes associated with agricultural productivity were assessed in the TD-treated samples and compared with untreated samples. Soil organic carbon decreased more than 25% in both the TD-treated topsoil and the subsoil, and total aggregation decreased by 20% in the topsoil but was unaffected in the subsoil. The alteration in these physical characteristics explains a 400% increase in saturated hydraulic conductivity in treated samples as well as a decrease in water retention at both field capacity and permanent wilting point. The changes in soil properties identified in this study suggest that TD-treated soils may still be suitable for sustaining vegetation, although likely at a slightly diminished capacity when directly compared with untreated soils. PMID:27380094

  4. Sources and remediation techniques for mercury contaminated soil.


    Xu, Jingying; Bravo, Andrea Garcia; Lagerkvist, Anders; Bertilsson, Stefan; Sjöblom, Rolf; Kumpiene, Jurate


    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. PMID:25454219

  5. Electrokinetic In Situ Treatment of Metal-Contaminated Soil

    NASA Technical Reports Server (NTRS)

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


    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

  6. 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.

  7. Chemical fingerprinting of hydrocarbon-contamination in soil.


    Boll, Esther S; Nejrup, Jens; Jensen, Julie K; Christensen, Jan H


    Chemical fingerprinting analyses of 29 hydrocarbon-contaminated soils were performed to assess the soil quality and determine the main contaminant sources. The results were compared to an assessment based on concentrations of the 16 priority polycyclic aromatic hydrocarbons pointed out by the U.S. Environmental Protection Agency (EPAPAH16) and total petroleum hydrocarbon (TPH). The chemical fingerprinting strategy proposed in this study included four tiers: (i) qualitative analysis of GC-FID chromatograms, (ii) comparison of the chemical composition of both un-substituted and alkyl-substituted polycyclic aromatic compounds (PACs), (iii) diagnostic ratios of selected PACs, and (iv) multivariate data analysis of sum-normalized PAC concentrations. The assessment criteria included quantitative analysis of 19 PACs and C1-C4 alkyl-substituted homologues of naphthalene, fluorene, dibenzothiophene, phenanthrene, pyrene, and chrysene; and 13 oxygenated polycyclic aromatic compounds (O-PACs). The chemical composition of un-substituted and alkyl-substituted PACs and visual interpretation of GC-FID chromatograms were in combination successful in differentiating pyrogenic and petrogenic hydrocarbon sources and in assessing weathering trends of hydrocarbon contamination in the soils. Multivariate data analysis of sum-normalized concentrations could as a stand-alone tool distinguish between hydrocarbon sources of petrogenic and pyrogenic origin, differentiate within petrogenic sources, and detect weathering trends. Diagnostic ratios of PACs were not successful for source identification of the heavily weathered hydrocarbon sources in the soils. The fingerprinting of contaminated soils revealed an underestimation of PACs in petrogenic contaminated soils when the assessment was based solely on EPAPAH16. As alkyl-substituted PACs are dominant in petrogenic sources, the evaluation of the total load of PACs based on EPAPAH16 was not representative. Likewise, the O-PACs are not

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

    SciTech Connect

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


    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 lower 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.

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

    SciTech Connect

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


    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 lower 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.


    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,...

  11. Phytoremediation of heavy metal contaminated soil by Jatropha curcas.


    Chang, Fang-Chih; Ko, Chun-Han; Tsai, Ming-Jer; Wang, Ya-Nang; Chung, Chin-Yi


    This study employed Jatropha curcas (bioenergy crop plant) to assist in the removal of heavy metals from contaminated field soils. Analyses were conducted on the concentrations of the individual metals in the soil and in the plants, and their differences over the growth periods of the plants were determined. The calculation of plant biomass after 2 years yielded the total amount of each metal that was removed from the soil. In terms of the absorption of heavy metal contaminants by the roots and their transfer to aerial plant parts, Cd, Ni, and Zn exhibited the greatest ease of absorption, whereas Cu, Cr, and Pb interacted strongly with the root cells and remained in the roots of the plants. J. curcas showed the best absorption capability for Cd, Cr, Ni, and Zn. This study pioneered the concept of combining both bioremediation and afforestation by J. curcas, demonstrated at a field scale. PMID:25236867

  12. [Bio-remediation techniques of crude oil contaminated soils].


    Li, Peijun; Guo, Shuhai; Sun, Tieheng; Tai, Peidong; Zhang, Chungui; Bai, Yuxing; Sun, Qiang; Sheng, Ping


    The bioremediation of soils contaminated by different types of petroleum were carried out with composting process in a prepared bed. By the measures of nutrient- and microbiological agent addition, and moisture- and pH control, an ideal environment for microbes were obtained. When total petroleum hydrocarbons, which consist of thin oil, high condensation oil, special viscous oil, and viscous oil, were in the range of 25.8-77.2 dry soil, the petroleum removal rate could reach 38.37-56.74% by 2 months operation. The contents of aromatic hydrocarbon, asphaltum and resin were important factors controlling the degradation of petroleum. 6 fungi, 6 bacteria and 1 actinomyces were found to be the dominant strains for petroleum degradation. The results could provide theoretical bases for remediation of soil contaminated by petroleum. PMID:12625007

  13. Electrokinetic treatment of firing ranges containing tungsten-contaminated soils.


    Braida, Washington; Christodoulatos, Christos; Ogundipe, Adebayo; Dermatas, Dimitris; O'Connor, Gregory


    Tungsten-based alloys and composites are being used and new formulations are being considered for use in the manufacturing of different types of ammunition. The use of tungsten heavy alloys (WHA) in new munitions systems and tungsten composites in small caliber ammunition could potentially release substantial amounts of this element into the environment. Although tungsten is widely used in industrial and military applications, tungsten's potential environmental and health impacts have not been thoroughly addressed. This necessitates the research and development of remedial technologies to contain and/or remove tungsten from soils that may serve as a source for water contamination. The current work investigates the feasibility of using electrokinetics for the remediation of tungsten-contaminated soils in the presence of other heavy metals of concern such as Cu and Pb with aim to removing W from the soil while stabilizing in situ, Pb and Cu. PMID:17686582

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  15. Electrokinetic remediation of six emerging organic contaminants from soil.


    Guedes, Paula; Mateus, Eduardo P; Couto, Nazaré; Rodríguez, Yadira; Ribeiro, Alexandra B


    Some organic contaminants can accumulate in organisms and cause irreversible damages in biological systems through direct or indirect toxic effects. In this study the feasibility of the electrokinetic (EK) process for the remediation of 17β-oestradiol (E2), 17α-ethinyloestradiol (EE2), bisphenol A (BPA), nonylphenol (NP), octylphenol (OP) and triclosan (TCS) in soils was studied in a stationary laboratory cell. The experiments were conducted using a silty loam soil (S2) at 0, 10 and 20mA and a sandy soil (S3) at 0 and 10 mA. A pH control in the anolyte reservoir (pH>13) at 10 mA was carried out using S2, too. Photo and electrodegradation experiments were also fulfilled. Results showed that EK is a viable method for the remediation of these contaminants, both through mobilization by electroosmotic flow (EOF) and electrodegradation. As EOF is very sensible to soil pH, the control in the anolyte increased EOF rate, consequently enhancing contaminants mobilization towards the cathode end. The extent of the mobilization towards the electrode end was mainly dependent on compounds solubility and octanol-water partition coefficient. In the last 24h of experiments, BPA presented the highest mobilization rate (ca. 4 μg min(-1)) with NP not being detected in the catholyte. At the end of all experiments the percentage of contaminants that remained in the soil ranged between 17 and 50 for S2, and between 27 and 48 for S3, with no statistical differences between treatments. The mass balance performed showed that the amount of contaminant not detected in the cell is similar to the quantity that potentially may suffer photo and electrodegradation. PMID:24997283

  16. Identifying root exudates in field contaminated soil systems

    NASA Astrophysics Data System (ADS)

    Rosenfeld, C.; Martinez, C. E.


    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

  17. Assessment of lead bioaccessibility in peri-urban contaminated soils.


    Smith, Euan; Weber, John; Naidu, Ravi; McLaren, Ronald G; Juhasz, Albert L


    Lead (Pb) bioaccessibility was assessed in a range of peri-urban soils (n=31) with differing sources of Pb contamination, including shooting range soils, and soils affected by incinerator, historical fill, mining/smelting, and gasworks activities. A gossan soil sample was also included. Lead bioaccessibility was determined using both gastric and intestinal phases of the SBRC in vitro assay and in vitro data was then incorporated into in vivo-in vitro regression equations to calculate Pb relative bioavailability. Lead bioaccessibility ranged from 26.8-105.2% to 5.5-102.6% for gastric and intestinal phase extractions respectively. Generally, Pb bioaccessibility was highest in the shooting range soils and lowest in the gossan soil. Predictions of relative Pb bioavailability derived from in vitro data were comparable for shooting ranges soils, but highly variable for the other soils examined. For incinerator, historical fill, gasworks and gossan soils, incorporating in vitro gastric data into the in vivo-in vitro regression equation resulting in more conservative Pb relative bioavailability values than those derived using the intestinal in vitro data. PMID:21115224

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

    NASA Astrophysics Data System (ADS)

    Barbafieri, Meri


    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

  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...


    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...

  1. Enhancing agents for phytoremediation of soil contaminated by cyanophos.


    Ali Romeh, Ahmed


    Cyanophos is commonly used in Egypt to control various agricultural and horticultural pests. It is a strong contaminant in the crop culturing environments because it is highly persistent and accumulates in the soil. This contaminant can be removed by phytoremediation, which is the use of plants to clean-up pollutants. Here we tested several several strategies to improve the effectiveness of this technology, which involved various techniques to solubilize contaminants. The phytoremediation efficiency of Plantago major L. was improved more by liquid silicon dioxide (SiO₂) than by other solubility-enhancing agents, resulting in the removal of significant amounts of cyanophos from contaminated soil. Liquid SiO₂ increased the capacity of P. major L. to remove cyanophos from soil by 45.9% to 74.05%. In P. major L. with liquid SiO₂, leaves extracted more cyanophos (32.99 µg/g) than roots (13.33 µg/g) over 3 days. The use of solubilization agents such as surfactants, hydroxypropyl-ß-cyclodextrin (HPßCD), natural humic acid acid (HA), and Tween 80 resulted in the removal of 60 convergents of cyanophos from polluted soil. Although a batch equilibrium technique showed that use of HPßCD resulted in the efficient removal of cyanophos from soil, a greater amount of cyanophos was removed by P. major L. with SiO₂. Moreover, a large amount of cyanophos was removed from soil by rice bran. This study indicates that SiO₂ can improve the efficiency of phytoremediation of cyanophos. PMID:25847752

  2. Ecotoxicity of a polycyclic aromatic hydrocarbon (PAH)-contaminated soil.


    Eom, I C; Rast, C; Veber, A M; Vasseur, P


    Soil samples from a former cokery site polluted with polycyclic aromatic hydrocarbons (PAHs) were assessed for their toxicity to terrestrial and aquatic organisms and for their mutagenicity. The total concentration of the 16 PAHs listed as priority pollutants by the US Environmental Protection Agency (US-EPA) was 2634+/-241 mg/kgdw in soil samples. The toxicity of water-extractable pollutants from the contaminated soil samples was evaluated using acute (Vibrio fischeri; Microtox test, Daphnia magna) and chronic (Pseudokirchneriella subcapitata, Ceriodaphnia dubia) bioassays and the EC values were expressed as percentage water extract in the test media (v/v). Algal growth (EC50-3d=2.4+/-0.2% of the water extracts) and reproduction of C. dubia (EC50-7d=4.3+/-0.6%) were the most severely affected, compared to bacterial luminescence (EC50-30 min=12+/-3%) and daphnid viability (EC50-48 h=30+/-3%). The Ames and Mutatox tests indicated mutagenicity of water extracts, while no response was found with the umu test. The toxicity of the soil samples was assessed on the survival and reproduction of earthworms (Eisenia fetida) and collembolae (Folsomia candida), and on the germination and growth of higher plants (Lactuca sativa L.: lettuce and Brassica chinensis J.: Chinese cabbage). The EC50 values were expressed as percentage contaminated soil in ISO soil test medium (weight per weight-w/w) and indicated severe effects on reproduction of the collembola F. candida (EC50-28 d=5.7%) and the earthworm E. fetida (EC50-28 d=18% and EC50-56 d=8%, based on cocoon and juvenile production, respectively). Survival of collembolae was already affected at a low concentration of the contaminated soil (EC50-28 d=11%). The viability of juvenile earthworms was inhibited at much lower concentrations of the cokery soil (EC50-14 d=28%) than the viability of adults (EC50-14 d=74%). Only plant growth was inhibited (EC50-17d=26%) while germination was not. Chemical analyses of water extracts allowed

  3. Evaluation of soil flushing of complex contaminated soil: an experimental and modeling simulation study.


    Yun, Sung Mi; Kang, Christina S; Kim, Jonghwa; Kim, Han S


    The removal of heavy metals (Zn and Pb) and heavy petroleum oils (HPOs) from a soil with complex contamination was examined by soil flushing. Desorption and transport behaviors of the complex contaminants were assessed by batch and continuous flow reactor experiments and through modeling simulations. Flushing a one-dimensional flow column packed with complex contaminated soil sequentially with citric acid then a surfactant resulted in the removal of 85.6% of Zn, 62% of Pb, and 31.6% of HPO. The desorption distribution coefficients, KUbatch and KLbatch, converged to constant values as Ce increased. An equilibrium model (ADR) and nonequilibrium models (TSNE and TRNE) were used to predict the desorption and transport of complex contaminants. The nonequilibrium models demonstrated better fits with the experimental values obtained from the column test than the equilibrium model. The ranges of KUbatch and KLbatch were very close to those of KUfit and KLfit determined from model simulations. The parameters (R, β, ω, α, and f) determined from model simulations were useful for characterizing the transport of contaminants within the soil matrix. The results of this study provide useful information for the operational parameters of the flushing process for soils with complex contamination. PMID:25698434

  4. Sand amendment enhances bioelectrochemical remediation of petroleum hydrocarbon contaminated soil.


    Li, Xiaojing; Wang, Xin; Ren, Zhiyong Jason; Zhang, Yueyong; Li, Nan; Zhou, Qixing


    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. PMID:26135976

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


    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


    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. PMID:27337912

  6. Cytotoxic and genotoxic potential of tannery waste contaminated soils.


    Masood, Farhana; Malik, Abdul


    Soil samples from agricultural fields in the vicinity of industrial area of Jajmau, Kanpur (India) were collected and found to be heavily contaminated with various toxic heavy metals. GC-MS analysis revealed the presence of organic compounds mainly phthalates in contaminated soils. Samples were extracted using dichloromethane (DCM) and hexane solvents, and the extracts were assayed for genotoxic potential using three different bioassays namely Ames Salmonella/mammalian microsome test, DNA repair defective Escherichia coli K-12 mutants and Allium cepa chromosomal aberration assay. TA98 was found to be the most sensitive strain to all the soil extracts tested. The highest mutagenic potential was observed in DCM extracts of soil as compared with hexane extracts for each strain of Salmonella typhimurium. DCM extracts of the soil exhibited maximum damage to the cells at a dose of 40 μl of soil extracts/ml of culture after a 6-h treatment. The survival was 23% in polA, 40% in lexA and 53% in recA mutants when treated with DCM extract of site I. In A. cepa assay, all the test concentrations of soil extracts (5-100%) affected mitotic index in a dose-dependent manner and several types of abnormalities were observed at different mitotic stages with the treatments: C-mitosis, anaphase bridges, laggards, binucleated cells, stickiness, broken and unequal distributions of chromosomes at anaphase stage of cell division. The soil is accumulating a large number of pollutants as a result of wastewater irrigation and this practice of accumulation has an adverse impact on soil health. PMID:23268142

  7. Enrofloxacin at environmentally relevant concentrations enhances uptake and toxicity of cadmium in the earthworm Eisenia fetida in farm soils.


    Li, Yinsheng; Tang, Hao; Hu, Yingxiu; Wang, Xiuhong; Ai, Xiaojie; Tang, Li; Matthew, Cory; Cavanagh, Jo; Qiu, Jiangping


    Individual and combined effects of enrofloxacin (EF) and cadmium (Cd) on the earthworm Eisenia fetida at environmentally relevant concentrations were investigated. EF is a veterinary antibiotic; Cd is an impurity in phosphatic fertiliser. For both, residues may accumulate in farm soils. In laboratory tests, over 98% of spiked EF was adsorbed by farm soils, with a half-life >8 weeks. However, earthworms absorbed less than 20% of spiked EF. Earthworms in soil with EF concentration 10 mg kg(-1) soil experienced transient oxidative stress and exhibited reduced burrowing activity and respiration after an 8-week exposure; EF at 0.1 and 1.0 mg kg(-1) soil did not elicit toxicity symptoms. When both were added, Cd did not affect EF uptake, but each increment of spiked EF increased Cd bioaccumulation and associated oxidative stress of earthworms, and also caused decreased burrow length and CO2 production. However, metallothionein induction was not affected. The enhanced toxicity of Cd to earthworms in the presence of EF at low environmental concentrations may have implications for the health and reproductive success of earthworm populations and highlights the importance of understanding effects of antibiotic contamination of farm soils, and of awareness of environmental effects from interaction between multiple contaminants. PMID:26852206

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


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


    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. PMID:27233045

  9. Chelant extraction of heavy metals from contaminated soils.


    Peters, R W


    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

  10. Investigating the control of mercury volatilization from contaminated soil

    NASA Astrophysics Data System (ADS)

    Steffy, D. A.; Nichols, A.


    In previous investigations of growing earthworms, Lumbricus terrestris, in contaminated soil, we have found that volatilization of mercury (Hg) to be an active process. The question to be answered is what causes the reduction of Hg to a more volatile state in the soil, could it be the earthworms? A series of laboratory tests were conducted to determine the mechanism of Hg reduction. The tests revealed that earthworms bioaccumulate the Hg in their tissue, but do not aid in the reduction process. Microbial reduction of the Hg appears to be the mechanism. Two dissimilar soil types were tested; both were heated for 96 hours at 100oC. After cooling, both soil types were spiked with 100 mg of Hg per Kg of soil. Integrated Hg vapor samples were collected immediately above the soil surface over a 3 day period and analyzed by cold vapor atomic adsorption. After heat treatment both soil types had a statistically significantly higher rate of volatilization than unheated soils. We interpret this result as indicating that heating preferentially selected microbial spores that facilitated the Hg reduction.

  11. Subchronic exposure of mice to Love Canal soil contaminants

    SciTech Connect

    Silkworth, J.B.; McMartin, D.N.; Rej, R.; Narang, R.S.; Stein, V.B.; Briggs, R.G.; Kaminsky, L.S.


    The health hazard potential of soil collected from the surface of the Love Canal chemical dump site in Niagara Falls, New York, was assessed in 90-day exposure studies. Female CD-1 mice were exposed to two concentrations of the volatile components of 1 kg of soil with and without direct soil contact. Control mice were identically housed but without soil. The soil was replaced weekly and 87 compounds were detected in the air in the cages above fresh and 7-day-old soil as analyzed by gas chromatography/mass spectrometry. The concentration of many of these compounds decreased during the 7-day exposure cycle. Histopathologic, hematologic, and serum enzyme studies followed necropsy of all mice. There was no mortality of mice exposed for up to 90 days under any condition. Thymus and spleen weights relative to body weight were increased after 4 weeks of exposure by inhalation but not after 8 or 12 weeks of exposure. alpha-, beta-, and delta- Benzenehexachlorides , pentachlorobenzene, and hexachlorobenzene were detected in liver tissue from these animals. Mice exposed to 5- to 10-fold elevated concentration of volatiles had increased body and relative kidney weights. There was no chemically induced lesion in any animal exposed only to the volatile soil contaminants. Mice exposed by direct contact with the soil without elevated volatile exposure had increased body (10%) and relative liver weights (169%). Centrolobular hepatocyte hypertrophy, which involved 40 to 70% of the lobules, was observed in all mice in this group.

  12. Electrokinetic treatment of contaminated soils, sludges, and lagoons. Final report

    SciTech Connect

    Wittle, J.K.; Pamukcu, S.


    The electrokinetic process is an emerging technology for in-situ soil decontamination, in which chemical species, both ionic and nonionic are transported to an electrode site in soil. These products are subsequently removed from the ground via collection systems engineered for each specific application. Electrokinetics refer to movement of water, ions and charged particles relative to one another under the action of an applied direct current electric field. In a porous compact matrix of surface charged particles such as soil, the ion containing pore fluid may be made to flow to collection sites under the applied field. This report describes the effort undertaken to investigate electrokinetically enhanced transport of soil contaminants in synthetic systems. These systems consisted of clay or clay-sand mixtures containing known concentration of a selected heavy metal salt solution or an organic compound. Metals, surrogate radio nuclides and organic compounds evaluated in the program were representatives of those found at a majority of DOE sites. Degree of removal of these metals from soil by the electrokinetic treatment process was assessed through the metal concentration profiles generated across the soil between the electrodes. The best removals, from about 85 to 95% were achieved at the anode side of the soil specimens. Transient pH change had an effect on the metal movement via transient creation of different metal species with different ionic mobilities, as well as changing of the surface characteristics of the soil medium.

  13. Effects of past copper contamination and soil structure on copper leaching from soil.


    Paradelo, Marcos; Moldrup, Per; Arthur, Emmanuel; Naveed, Muhammad; Holmstrup, Martin; López-Periago, Jose E; de Jonge, Lis W


    Copper contamination affects biological, chemical, and physical soil properties and associated ecological functions. Changes in soil pore organization as a result of Cu contamination can dramatically affect flow and contaminant transport in polluted soils. This study assessed the influence of soil structure on the movement of water and Cu in a long-term polluted soil. Undisturbed soil cores collected along a Cu gradient (from about 20 to about 3800 mg Cu kg soil) were scanned using X-ray computed tomography (CT). Leaching experiments were performed to analyze tracer transport, colloid leaching, and dissolved organic carbon (DOC) and Cu losses. The 5% arrival time () and apparent dispersivity (λ) for tracer breakthrough were calculated by fitting the experimental data to a nonparametric, double-lognormal probability density function. Soil bulk density, which did not follow the Cu gradient, was the main driver of preferential flow, while macroporosity determined by X-ray CT (for pores >180 μm) proved the best predictor of solute transport. Higher preferential flow due to the presence of well-aligned pores and small cracks controlled water movement in compacted soil. Transport of Cu was rapid during the first flush (≈1 pore volume) in association with the movement of colloid particles, followed by slower transport in association with the movement of DOC in the soil solution. The relative amount of Cu released was strongly correlated with macroporosity as determined by X-ray CT, indicating the promising potential of this visualization technique for predicting contaminant transport through soil. PMID:25602425

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


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


    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. PMID:25841071

  15. Migration of Contaminated Soil and Airborne Particulates to Indoor Dust

    PubMed Central

    Layton, David W.; Beamer, Paloma I.


    We have developed a modeling and measurement framework for assessing transport of contaminated soils and airborne particulates into a residence, their subsequent distribution indoors via resuspension and deposition processes, and removal by cleaning and building exhalation of suspended particles. The model explicitly accounts for the formation of house dust as a mixture of organic matter (OM) such as shed skin cells and organic fibers, soil tracked-in on footwear, and particulate matter (PM) derived from the infiltration of outdoor air. We derived formulas for use with measurements of inorganic contaminants, crustal tracers, OM, and PM to quantify selected transport parameters. Application of the model to residences in the U.S. Midwest indicates that As in ambient air can account for nearly 60% of the As input to floor dust, with soil track-in representing the remainder. Historic data on Pb contamination in Sacramento, CA, was used to reconstruct sources of Pb in indoor dust, showing that airborne Pb was likely the dominant source in the early 1980s. However, as airborne Pb levels declined due to the phase out of leaded gasoline, soil resuspension and track-in eventually became the primary sources of Pb in house dust. PMID:19924944

  16. Organochlorinated pesticide degrading microorganisms isolated from contaminated soil.


    Lovecka, Petra; Pacovska, Iva; Stursa, Petr; Vrchotova, Blanka; Kochankova, Lucie; Demnerova, Katerina


    Degradation of selected organochlorinated pesticides (γ-hexachlorocyclohexane - γ-HCH, dichlorodiphenyltrichloroethane - DDT, hexachlorobenzene - HCB) by soil microorganisms was studied. Bacterial strains isolated from contaminated soil from Klatovy-Luby, Hajek and Neratovice, Czech Republic, capable of growth on the selected pesticides were isolated and characterised. These isolates were subjected to characterisation and identification by MS MALDI-TOF of whole cells and sequence analysis of 16S rRNA genes. The isolates were screened by gas chromatography for their ability to degrade the selected pesticides. Some isolates were able to degrade pesticides, and the formation of degradation products (γ-pentachlorocyclohexane (γ-PCCH), dichlorodiphenyldichloroethylene (DDE) and dichlorodiphenyldichloroethane (DDD)) observed in liquid culture confirmed their degradation capability. The isolates and DNA samples isolated from the contaminated soil were also screened for the bphA1 gene (encoding biphenyl-2,3-dioxygenase, the first enzyme in the PCB degradation pathway) and its occurrence was demonstrated. The isolates were also screened for the presence of linA, encoding dehydrochlorinase, the first enzyme of the HCH degradation pathway. The linA gene could not be found in any of the tested isolates, possibly due to the high specificity of the primers used. The isolates with the most effective degradation abilities could be used for further in situ bioremediation experiments with contaminated soil. PMID:25094051

  17. Characterization of bacterial communities in heavy metal contaminated soils.


    Roane, T M; Kellogg, S T


    Heavy metal pollution is a principle source of environmental contamination. We analyzed heavy metal impacted soil microbial communities and found that, in general, although lead adversely affected biomass, metabolic activity, and diversity, autochthonous lead- and cadmium-resistant isolates were found. In several metal-stressed soils, the microbial community consisted of two populations, either resistant or sensitive to lead. Additionally, a lead-resistant isolate was isolated from a control soil with no known previous exposure to lead, suggesting widespread lead resistance. Lead-resistant genera isolated included Pseudomonas, Bacillus, Corynebacterium, and Enterobacter species. Plasmids, ranging from 5 to 260 kb, were not detected through standard purifications from lead-resistant isolates. Positive correlations existed between antibiotic resistance and isolation habitat for lead-resistant strains, microbial metabolic activity and soil type, soluble lead concentration and microbial diversity, and arsenic concentration and total or viable cell concentrations. PMID:8801006

  18. Metal contamination of vineyard soils in wet subtropics (southern Brazil).


    Mirlean, Nicolai; Roisenberg, Ari; Chies, Jaqueline O


    The vine-growing areas in Brazil are the dampest in the world. Copper maximum value registered in this study was as much as 3200 mg kg(-1), which is several times higher than reported for vineyard soils in temperate climates. Other pesticide-derived metals accumulate in the topsoil layer, surpassing in the old vineyards the background value several times for Zn, Pb, Cr and Cd. Copper is transported to deeper soils' horizons and can potentially contaminate groundwater. The soils from basaltic volcanic rocks reveal the highest values of Cu extracted with CaCl(2), demonstrating a high capacity of copper transference into plants. When evaluating the risks of copper's toxic effects in subtropics, the soils from rhyolitic volcanic rocks are more worrisome, as the Cu extracted with ammonium acetate 1M surpasses the toxic threshold as much as 4-6 times. PMID:17321651

  19. 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.


    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

  20. Sources of arsenic and fluoride in highly contaminated soils causing groundwater contamination in Punjab, Pakistan

    SciTech Connect

    Farooqi, A.; Masuda, H.; Siddiqui, R.; Naseem, M.


    Highly contaminated groundwater, with arsenic (As) and fluoride (F{sup -}) concentrations of up to 2.4 and 22.8 mg/L, respectively, has been traced to anthropogenic inputs to the soil. In the present study, samples collected from the soil surface and sediments from the most heavily polluted area of Punjab were analyzed to determine the F{sup -} and As distribution in the soil. The surface soils mainly comprise permeable aeolian sediment on a Pleistocene terrace and layers of sand and silt on an alluvial flood plain. Although the alluvial sediments contain low levels of F, the terrace soils contain high concentrations of soluble F{sup -} (maximum, 16 mg/kg; mean, 4 mg/kg; pH > 8.0). Three anthropogenic sources were identified as fertilizers, combusted coal, and industrial waste, with phosphate fertilizer being the most significance source of F{sup -} accumulated in the soil. The mean concentration of As in the surface soil samples was 10.2 mg/kg, with the highest concentration being 35 mg/kg. The presence of high levels of As in the surface soil implies the contribution of air pollutants derived from coal combustion and the use of fertilizers. Intensive mineral weathering under oxidizing conditions produces highly alkaline water that dissolves the F{sup -} and As adsorbed on the soil, thus releasing it into the local groundwater.

  1. Diuron mobility through vineyard soils contaminated with copper.


    Jacobson, Astrid R; Dousset, Sylvie; Guichard, Nathalie; Baveye, Philippe; Andreux, Francis


    The herbicide diuron is frequently applied to vineyard soils in Burgundy, along with repeated treatments with Bordeaux mixture (a blend of copper sulfate and calcium hydroxide) that result in elevated copper concentrations. Cu could in principle affect the fate and transport of diuron or its metabolites in the soil either directly by complexation or indirectly by altering the populations or activity of microbes involved in their degradation. To assess the effect of high Cu concentrations on diuron transport, an experiment was designed with ten undisturbed columns of calcareous and acidic soils contaminated with 17--509 mg kg(-1) total Cu (field-applied). Grass was planted on three columns. Diuron was applied to the soils in early May and in-ground lysimeters were exposed to outdoor conditions until November. Less than 1.2% of the diuron applied was found in the leachates as diuron or its metabolites. Higher concentrations were found in the effluents from the grass-covered columns (0.1--0.45%) than from the bare-soil columns (0.02--0.14%), and they were correlated with increases in dissolved organic carbon. The highest amounts of herbicide were measured in acidic-soil column leachates (0.98--1.14%) due to the low clay and organic matter contents of these soils. Cu also leached more readily through the acidic soils (32.8--1042 microg) than in the calcareous soils (9.5--63.4 microg). Unlike in the leachates, the amount of diuron remaining in the soils at the end of the experiment was weakly related to the Cu concentrations in the soils. PMID:15951080

  2. 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.


    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.

  3. Remediation of lead and cadmium-contaminated soils.


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


    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. PMID:26515924

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


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


    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.

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


    Lindgren, Eric R.; Mattson, Earl D.


    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.

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


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


    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. PMID:25010741

  7. Ecotoxicity of pentachlorophenol in contaminated soil as affected by soil type.


    Banks, M K; Schwab, A P


    Four uncontaminated soils were chosen with a wide range of pH, organic carbon, and clay content to allow us to determine the properties that were most influential on pentachlorophenol (PCP) toxicity. The soils were contaminated in the laboratory at concentrations of 50 and 100 mg/kg and target organisms were exposed to the contaminated soil. Germination and emergence of lettuce seedlings was found to be dependent upon PCP concentration and soil type, and responses were highly correlated to extractable concentrations. Earthworms were sensitive to PCP, regardless of soil properties, and mortality was observed in most samples at the 100 mg/kg concentration. Toxic responses by the worms were not strongly related to soil properties or extractable concentrations. The importance of soil chemical and physical properties on toxicity and bioavailability depends upon the target organism. In the case of lettuce seedlings, PCP is acquired through the aqueous phase; therefore, the chemical interaction between PCP and soil controls toxicity. Since earthworms ingest soil and potentially can change the chemical environment of exposure, the impact of soil properties on PCP toxicity is less apparent. PMID:16423718

  8. Phytoremediation of mercury-contaminated soils by Jatropha curcas.


    Marrugo-Negrete, José; Durango-Hernández, José; Pinedo-Hernández, José; Olivero-Verbel, Jesús; Díez, Sergi


    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. PMID:25655698

  9. Remediation of PCB contaminated soils using iron nano-particles.


    Varanasi, Patanjali; Fullana, Andres; Sidhu, Sukh


    In this study, iron nano-particles were used to remediate PCB contaminated soil and an attempt was made to maximize PCB destruction in each treatment step. The results show that nano-particles do aid in the dechlorination process and high PCB destruction efficiencies can be achieved. The destruction efficiency during the preliminary treatment (mixing of soil and iron nano-particles in water) can be increased by increasing the water temperature. The maximum thermal destruction (pyrolysis/combustion of soil after preliminary treatment) of soil-bound PCBs occurs at 300 degrees C in air. A minimum total PCB destruction efficiency of 95% can be achieved by this process. The effect of changing treatment parameters such as type of mixing, time of mixing and mixing conditions and application of other catalysts like iron oxide and V(2)O(5)/TiO(2) was also investigated. It was found that at 300 degrees C in air, iron oxide and V(2)O(5)/TiO(2) are also good catalysts for remediating PCB contaminated soils. PMID:16962632

  10. Characterization and remediation of soils contaminated with uranium.


    Gavrilescu, Maria; Pavel, Lucian Vasile; Cretescu, Igor


    Environmental contamination caused by radionuclides, in particular by uranium and its decay products is a serious problem worldwide. The development of nuclear science and technology has led to increasing nuclear waste containing uranium being released and disposed in the environment. The objective of this paper is to develop a better understanding of the techniques for the remediation of soils polluted with radionuclides (uranium in particular), considering: the chemical forms of uranium, including depleted uranium (DU) in soil and other environmental media, their characteristics and concentrations, and some of the effects on environmental and human health; research issues concerning the remediation process, the benefits and results; a better understanding of the range of uses and situations for which each is most appropriate. The paper addresses the main features of the following techniques for uranium remediation: natural attenuation, physical methods, chemical processes (chemical extraction methods from contaminated soils assisted by various suitable chelators (sodium bicarbonate, citric acid, two-stage acid leaching procedure), extraction using supercritical fluids such as solvents, permeable reactive barriers), biological processes (biomineralization and microbial reduction, phytoremediation, biosorption), and electrokinetic methods. In addition, factors affecting uranium removal from soils are furthermore reviewed including soil characteristics, pH and reagent concentration, retention time. PMID:18771850