Microbial Communities in Contaminated Sediments, Associated with Bioremediation of Uranium to Submicromolar Levels▿

PubMed Central

Cardenas, Erick; Wu, Wei-Min; Leigh, Mary Beth; Carley, Jack; Carroll, Sue; Gentry, Terry; Luo, Jian; Watson, David; Gu, Baohua; Ginder-Vogel, Matthew; Kitanidis, Peter K.; Jardine, Philip M.; Zhou, Jizhong; Criddle, Craig S.; Marsh, Terence L.; Tiedje, James M.

2008-01-01

Microbial enumeration, 16S rRNA gene clone libraries, and chemical analysis were used to evaluate the in situ biological reduction and immobilization of uranium(VI) in a long-term experiment (more than 2 years) conducted at a highly uranium-contaminated site (up to 60 mg/liter and 800 mg/kg solids) of the U.S. Department of Energy in Oak Ridge, TN. Bioreduction was achieved by conditioning groundwater above ground and then stimulating growth of denitrifying, Fe(III)-reducing, and sulfate-reducing bacteria in situ through weekly injection of ethanol into the subsurface. After nearly 2 years of intermittent injection of ethanol, aqueous U levels fell below the U.S. Environmental Protection Agency maximum contaminant level for drinking water and groundwater (<30 μg/liter or 0.126 μM). Sediment microbial communities from the treatment zone were compared with those from a control well without biostimulation. Most-probable-number estimations indicated that microorganisms implicated in bioremediation accumulated in the sediments of the treatment zone but were either absent or in very low numbers in an untreated control area. Organisms belonging to genera known to include U(VI) reducers were detected, including Desulfovibrio, Geobacter, Anaeromyxobacter, Desulfosporosinus, and Acidovorax spp. The predominant sulfate-reducing bacterial species were Desulfovibrio spp., while the iron reducers were represented by Ferribacterium spp. and Geothrix spp. Diversity-based clustering revealed differences between treated and untreated zones and also within samples of the treated area. Spatial differences in community structure within the treatment zone were likely related to the hydraulic pathway and to electron donor metabolism during biostimulation. PMID:18456853

Understanding Uranium Behavior in a Reduced Aquifer

NASA Astrophysics Data System (ADS)

Janot, N.; Lezama-Pacheco, J. S.; Williams, K. H.; Bernier-Latmani, R.; Long, P. E.; Davis, J. A.; Fox, P. M.; Yang, L.; Giammar, D.; Cerrato, J. M.; Bargar, J.

2012-12-01

Uranium contamination of groundwater is a concern at several US Department of Energy sites, such Old Rifle, CO. Uranium transport in the environment is mainly controlled by its oxidation state, since oxidized U(VI) is relatively mobile, whereas U(IV) is relatively insoluble. Bio-remediation of contaminated aquifers aims at immobilizing uranium in a reduced form. Previous laboratory and field studies have shown that adding electron donor (lactate, acetate, ethanol) to groundwater stimulates the activity of metal- and sulfate-reducing bacteria, which promotes U(VI) reduction in contaminated aquifers. However, obtaining information on chemical and physical forms of U, Fe and S species for sediments biostimulated in the field, as well as kinetic parameters such as U(VI) reduction rate, is challenging due to the low concentration of uranium in the aquifers (typically < 10 ppm) and the expense of collecting large number of cores. An in-situ technique has been developed for studying uranium, iron and sulfur reduction dynamics during such bioremediation episodes. This technique uses in-well columns to obtain direct access to chemical and physical forms of U(IV) produced in the aquifer, evolving microbial communities, and trace and major ion groundwater constituents. While several studies have explored bioreduction of uranium under sulfate-reducing conditions, less attention has been paid to the initial iron-reducing phase, noted as being of particular importance to uranium removal. The aim of this work was to assess the formation of U(IV) during the early stages of a bio-remediation experiment at the Old Rifle site, CO, from early iron-reducing conditions to the transition to sulfate-reducing conditions. Several in-well chromatographic columns packed with sediment were deployed and were sampled at different days after the start of bio-reduction. X-ray absorption spectroscopy and X-ray microscopy were used to obtain information on Fe, S and U speciation and distribution. Chemical extractions of the reduced sediments have also been performed, to determine the rate of Fe(II) and U(IV) accumulation.

Bound Flavin-Cytochrome Model of Extracellular Electron Transfer in Shewanella oneidensis: Analysis by Free Energy Molecular (Postprint)

DTIC Science & Technology

2016-06-06

toxic chemicals,4 protection of steel from corrosion,5 or in bioremediation .6 Of special interest is the potential use of the exoelectrogens in... Bioremediation of Uranium-Contaminated Groundwater: A Systems Approach to Subsurface Biogeochemistry. Curr. Opin. Biotechnol. 2013, 24, 489−497. (7

Enrichment of specific protozoan populations during in situ bioremediation of uranium-contaminated groundwater.

PubMed

Holmes, Dawn E; Giloteaux, Ludovic; Williams, Kenneth H; Wrighton, Kelly C; Wilkins, Michael J; Thompson, Courtney A; Roper, Thomas J; Long, Philip E; Lovley, Derek R

2013-07-01

The importance of bacteria in the anaerobic bioremediation of groundwater polluted with organic and/or metal contaminants is well recognized and in some instances so well understood that modeling of the in situ metabolic activity of the relevant subsurface microorganisms in response to changes in subsurface geochemistry is feasible. However, a potentially significant factor influencing bacterial growth and activity in the subsurface that has not been adequately addressed is protozoan predation of the microorganisms responsible for bioremediation. In field experiments at a uranium-contaminated aquifer located in Rifle, CO, USA, acetate amendments initially promoted the growth of metal-reducing Geobacter species, followed by the growth of sulfate reducers, as observed previously. Analysis of 18S rRNA gene sequences revealed a broad diversity of sequences closely related to known bacteriovorous protozoa in the groundwater before the addition of acetate. The bloom of Geobacter species was accompanied by a specific enrichment of sequences most closely related to the ameboid flagellate, Breviata anathema, which at their peak accounted for over 80% of the sequences recovered. The abundance of Geobacter species declined following the rapid emergence of B. anathema. The subsequent growth of sulfate-reducing Peptococcaceae was accompanied by another specific enrichment of protozoa, but with sequences most similar to diplomonadid flagellates from the family Hexamitidae, which accounted for up to 100% of the sequences recovered during this phase of the bioremediation. These results suggest a prey-predator response with specific protozoa responding to increased availability of preferred prey bacteria. Thus, quantifying the influence of protozoan predation on the growth, activity and composition of the subsurface bacterial community is essential for predictive modeling of in situ uranium bioremediation strategies.

Enrichment of specific protozoan populations during in situ bioremediation of uranium-contaminated groundwater

PubMed Central

Holmes, Dawn E; Giloteaux, Ludovic; Williams, Kenneth H; Wrighton, Kelly C; Wilkins, Michael J; Thompson, Courtney A; Roper, Thomas J; Long, Philip E; Lovley, Derek R

2013-01-01

The importance of bacteria in the anaerobic bioremediation of groundwater polluted with organic and/or metal contaminants is well recognized and in some instances so well understood that modeling of the in situ metabolic activity of the relevant subsurface microorganisms in response to changes in subsurface geochemistry is feasible. However, a potentially significant factor influencing bacterial growth and activity in the subsurface that has not been adequately addressed is protozoan predation of the microorganisms responsible for bioremediation. In field experiments at a uranium-contaminated aquifer located in Rifle, CO, USA, acetate amendments initially promoted the growth of metal-reducing Geobacter species, followed by the growth of sulfate reducers, as observed previously. Analysis of 18S rRNA gene sequences revealed a broad diversity of sequences closely related to known bacteriovorous protozoa in the groundwater before the addition of acetate. The bloom of Geobacter species was accompanied by a specific enrichment of sequences most closely related to the ameboid flagellate, Breviata anathema, which at their peak accounted for over 80% of the sequences recovered. The abundance of Geobacter species declined following the rapid emergence of B. anathema. The subsequent growth of sulfate-reducing Peptococcaceae was accompanied by another specific enrichment of protozoa, but with sequences most similar to diplomonadid flagellates from the family Hexamitidae, which accounted for up to 100% of the sequences recovered during this phase of the bioremediation. These results suggest a prey–predator response with specific protozoa responding to increased availability of preferred prey bacteria. Thus, quantifying the influence of protozoan predation on the growth, activity and composition of the subsurface bacterial community is essential for predictive modeling of in situ uranium bioremediation strategies. PMID:23446832

Enrichment of specific protozoan populations during in situ bioremediation of uranium-contaminated groundwater

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

Holmes, Dawn; Giloteaux, L.; Williams, Kenneth H.

2013-07-28

The importance of bacteria in the anaerobic bioremediation of groundwater polluted with organic and/or metal contaminants is well-recognized and in some instances so well understood that modeling of the in situ metabolic activity of the relevant subsurface microorganisms in response to changes in subsurface geochemistry is feasible. However, a potentially significant factor influencing bacterial growth and activity in the subsurface that has not been adequately addressed is protozoan predation of the microorganisms responsible for bioremediation. In field experiments at a uranium-contaminated aquifer located in Rifle, CO, acetate amendments initially promoted the growth of metal-reducing Geobacter species followed by the growthmore » of sulfate-reducers, as previously observed. Analysis of 18S rRNA gene sequences revealed a broad diversity of sequences closely related to known bacteriovorous protozoa in the groundwater prior to the addition of acetate. The bloom of Geobacter species was accompanied by a specific enrichment of sequences most closely related to the amoeboid flagellate, Breviata anathema, which at their peak accounted for over 80% of the sequences recovered. The abundance of Geobacter species declined following the rapid emergence of B. anathema. The subsequent growth of sulfate-reducing Peptococcaceae was accompanied by another specific enrichment of protozoa, but with sequences most similar to diplomonadid flagellates from the family Hexamitidae, which accounted for up to 100% of the sequences recovered during this phase of the bioremediation. These results suggest a prey-predator response with specific protozoa responding to increased availability of preferred prey bacteria. Thus, quantifying the influence of protozoan predation on the growth, activity, and composition of the subsurface bacterial community is essential for predictive modeling of in situ uranium bioremediation strategies.« less

Monitoring Physical and Biogeochemical Dynamics of Uranium Bioremediation at the Intermediate Scale

NASA Astrophysics Data System (ADS)

Tarrell, A. N.; Figueroa, L. A.; Rodriguez, D.; Haas, A.; Revil, A.

2011-12-01

Subsurface uranium above desired levels for aquifer use categories exists naturally and from historic mining and milling practices. In situ bioimmobilization offers a cost effective alternative to conventional pump and treat methods by stimulating growth of microorganisms that lead to the reduction and precipitation of uranium. Vital to the long-term success of in situ bioimmobilization is the ability to successfully predict and demonstrate treatment effectiveness to assure that regulatory goals are met. However, successfully monitoring the progress over time is difficult and requires long-term stewardship to ensure effective treatment due to complex physical and biogeochemical heterogeneity. In order to better understand these complexities and the resultant effect on uranium immobilization, innovative systematic monitoring approaches with multiple performance indicators must be investigated. A key issue for uranium bioremediation is the long term stability of solid-phase reduction products. It has been shown that a combination of data from electrode-based monitoring, self-potential monitoring, oxidation reduction potential (ORP), and water level sensors provides insight for identifying and localizing bioremediation activity and can provide better predictions of deleterious biogeochemical change such as pore clogging. In order to test the proof-of-concept of these sensing techniques and to deconvolve redox activity from other electric potential changing events, an intermediate scale 3D tank experiment has been developed. Well-characterized materials will be packed into the tank and an artificial groundwater will flow across the tank through a constant-head boundary. The experiment will utilize these sensing methods to image the electrical current produced by bacteria as well as indications of when and where electrical activity is occurring, such as with the reduction of radionuclides. This work will expand upon current knowledge by exploring the behavior of uranium bioremediation at an intermediate scale, as well as examining the effects from introducing a flow field in a laboratory setting. Data collected from this experiment will help further characterize which factors are contributing to current increases. Additional information concerning the effect of geochemical changes in porosity may also be observed. The results of this work will allow the creation of a new data set collected from a more comprehensive laboratory monitoring network and will allow stakeholders to develop effective decision-making tools on the long-term remediation management at uranium contaminated sites. The data will also aid in the long-term prediction abilities of a reactive transport models. As in situ bioremediation offers a low cost alternative to ex situ treatment methods, the results of this work will help to both reduce cost at existing sites and enable treatment of sites that otherwise have no clear solution.

Genome-Based Models to Optimize In Situ Bioremediation of Uranium and Harvesting Electrical Energy from Waste Organic Matter

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

Lovley, Derek R

2012-12-28

The goal of this research was to provide computational tools to predictively model the behavior of two microbial communities of direct relevance to Department of Energy interests: 1) the microbial community responsible for in situ bioremediation of uranium in contaminated subsurface environments; and 2) the microbial community capable of harvesting electricity from waste organic matter and renewable biomass. During this project the concept of microbial electrosynthesis, a novel form of artificial photosynthesis for the direct production of fuels and other organic commodities from carbon dioxide and water was also developed and research was expanded into this area as well.

Extracellular reduction of uranium via Geobacter conductive pili as a protective cellular mechanism.

PubMed

Cologgi, Dena L; Lampa-Pastirk, Sanela; Speers, Allison M; Kelly, Shelly D; Reguera, Gemma

2011-09-13

The in situ stimulation of Fe(III) oxide reduction by Geobacter bacteria leads to the concomitant precipitation of hexavalent uranium [U(VI)] from groundwater. Despite its promise for the bioremediation of uranium contaminants, the biological mechanism behind this reaction remains elusive. Because Fe(III) oxide reduction requires the expression of Geobacter's conductive pili, we evaluated their contribution to uranium reduction in Geobacter sulfurreducens grown under pili-inducing or noninducing conditions. A pilin-deficient mutant and a genetically complemented strain with reduced outer membrane c-cytochrome content were used as controls. Pili expression significantly enhanced the rate and extent of uranium immobilization per cell and prevented periplasmic mineralization. As a result, pili expression also preserved the vital respiratory activities of the cell envelope and the cell's viability. Uranium preferentially precipitated along the pili and, to a lesser extent, on outer membrane redox-active foci. In contrast, the pilus-defective strains had different degrees of periplasmic mineralization matching well with their outer membrane c-cytochrome content. X-ray absorption spectroscopy analyses demonstrated the extracellular reduction of U(VI) by the pili to mononuclear tetravalent uranium U(IV) complexed by carbon-containing ligands, consistent with a biological reduction. In contrast, the U(IV) in the pilin-deficient mutant cells also required an additional phosphorous ligand, in agreement with the predominantly periplasmic mineralization of uranium observed in this strain. These findings demonstrate a previously unrecognized role for Geobacter conductive pili in the extracellular reduction of uranium, and highlight its essential function as a catalytic and protective cellular mechanism that is of interest for the bioremediation of uranium-contaminated groundwater.

Screening of bacterial strains isolated from uranium mill tailings porewaters for bioremediation purposes.

PubMed

Sánchez-Castro, Iván; Amador-García, Ahinara; Moreno-Romero, Cristina; López-Fernández, Margarita; Phrommavanh, Vannapha; Nos, Jeremy; Descostes, Michael; Merroun, Mohamed L

2017-01-01

The present work characterizes at different levels a number of bacterial strains isolated from porewaters sampled in the vicinity of two French uranium tailing repositories. The 16S rRNA gene from 33 bacterial isolates, corresponding to the different morphotypes recovered, was almost fully sequenced. The resulting sequences belonged to 13 bacterial genera comprised in the phyla Firmicutes, Actinobacteria and Proteobacteria. Further characterization at physiological level and metals/metalloid tolerance provided evidences for an appropriate selection of bacterial strains potentially useful for immobilization of uranium and other common contaminants. By using High Resolution Transmission Electron Microscope (HRTEM), this potential ability to immobilize uranium as U phosphate mineral phases was confirmed for the bacterial strains Br3 and Br5 corresponding to Arthrobacter sp. and Microbacterium oxydans, respectively. Scanning Transmission Electron Microscope- High-Angle Annular Dark-Field (STEM-HAADF) analysis showed U accumulates on the surface and within bacterial cytoplasm, in addition to the extracellular space. Energy Dispersive X-ray (EDX) element-distribution maps demonstrated the presence of U and P within these accumulates. These results indicate the potential of certain bacterial strains isolated from porewaters of U mill tailings for immobilizing uranium, likely as uranium phosphates. Some of these bacterial isolates might be considered as promising candidates in the design of uranium bioremediation strategies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Bioremediation of uranium contamination with enzymatic uranium reduction

USGS Publications Warehouse

Lovley, D.R.; Phillips, E.J.P.

1992-01-01

Enzymatic uranium reduction by Desulfovibrio desulfuricans readily removed uranium from solution in a batch system or when D. desulfuricans was separated from the bulk of the uranium-containing water by a semipermeable membrane. Uranium reduction continued at concentrations as high as 24 mM. Of a variety of potentially inhibiting anions and metals evaluated, only high concentrations of copper inhibited uranium reduction. Freeze-dried cells, stored aerobically, reduced uranium as fast as fresh cells. D. desulfuricans reduced uranium in pH 4 and pH 7.4 mine drainage waters and in uraniumcontaining groundwaters from a contaminated Department of Energy site. Enzymatic uranium reduction has several potential advantages over other bioprocessing techniques for uranium removal, the most important of which are as follows: the ability to precipitate uranium that is in the form of a uranyl carbonate complex; high capacity for uranium removal per cell; the formation of a compact, relatively pure, uranium precipitate.

Evidence of Geobacter-associated phage in a uranium-contaminated aquifer

PubMed Central

Holmes, Dawn E; Giloteaux, Ludovic; Chaurasia, Akhilesh K; Williams, Kenneth H; Luef, Birgit; Wilkins, Michael J; Wrighton, Kelly C; Thompson, Courtney A; Comolli, Luis R; Lovley, Derek R

2015-01-01

Geobacter species may be important agents in the bioremediation of organic and metal contaminants in the subsurface, but as yet unknown factors limit the in situ growth of subsurface Geobacter well below rates predicted by analysis of gene expression or in silico metabolic modeling. Analysis of the genomes of five different Geobacter species recovered from contaminated subsurface sites indicated that each of the isolates had been infected with phage. Geobacter-associated phage sequences were also detected by metagenomic and proteomic analysis of samples from a uranium-contaminated aquifer undergoing in situ bioremediation, and phage particles were detected by microscopic analysis in groundwater collected from sediment enrichment cultures. Transcript abundance for genes from the Geobacter-associated phage structural proteins, tail tube Gp19 and baseplate J, increased in the groundwater in response to the growth of Geobacter species when acetate was added, and then declined as the number of Geobacter decreased. Western blot analysis of a Geobacter-associated tail tube protein Gp19 in the groundwater demonstrated that its abundance tracked with the abundance of Geobacter species. These results suggest that the enhanced growth of Geobacter species in the subsurface associated with in situ uranium bioremediation increased the abundance and activity of Geobacter-associated phage and show that future studies should focus on how these phages might be influencing the ecology of this site. PMID:25083935

Bacterial community succession during in situ uranium bioremediation: spatial similarities along controlled flow paths.

PubMed

Hwang, Chiachi; Wu, Weimin; Gentry, Terry J; Carley, Jack; Corbin, Gail A; Carroll, Sue L; Watson, David B; Jardine, Phil M; Zhou, Jizhong; Criddle, Craig S; Fields, Matthew W

2009-01-01

Bacterial community succession was investigated in a field-scale subsurface reactor formed by a series of wells that received weekly ethanol additions to re-circulating groundwater. Ethanol additions stimulated denitrification, metal reduction, sulfate reduction and U(VI) reduction to sparingly soluble U(IV). Clone libraries of SSU rRNA gene sequences from groundwater samples enabled tracking of spatial and temporal changes over a 1.5-year period. Analyses showed that the communities changed in a manner consistent with geochemical variations that occurred along temporal and spatial scales. Canonical correspondence analysis revealed that the levels of nitrate, uranium, sulfide, sulfate and ethanol were strongly correlated with particular bacterial populations. As sulfate and U(VI) levels declined, sequences representative of sulfate reducers and metal reducers were detected at high levels. Ultimately, sequences associated with sulfate-reducing populations predominated, and sulfate levels declined as U(VI) remained at low levels. When engineering controls were compared with the population variation through canonical ordination, changes could be related to dissolved oxygen control and ethanol addition. The data also indicated that the indigenous populations responded differently to stimulation for bioreduction; however, the two biostimulated communities became more similar after different transitions in an idiosyncratic manner. The strong associations between particular environmental variables and certain populations provide insight into the establishment of practical and successful remediation strategies in radionuclide-contaminated environments with respect to engineering controls and microbial ecology.

Synchrotron X-ray characterization of mackinawite and uraninite relevant to bio-remediation of groundwater contaminated with uranium

NASA Astrophysics Data System (ADS)

Carpenter, J.; Hyun, S.; Hayes, K. F.

2010-12-01

Uranium (U) originating from mining operations for weapon manufacturing and nuclear energy production is a significant radionuclide contaminant in groundwater local to uranium mining, uranium milling, and uranium mill tailing (UMT) storage sites. In the USA, the Department of Energy (DOE) is currently overseeing approximately 24 Uranium Mill Tailing Remediation Action (UMTRA) sites which have collectively processed over 27 million tons of uranium ore1,2. In-Situ microbial bio-reduction of the highly mobile U6+ ion into the dramatically less mobile U4+ ion has been demonstrated as an effective remedial process to inhibit uranium migration in the aqueous phase3. The resistance of this process to oxidization and possible remobilization of U when bioremediation stops (and oxidants such as oxygen from the air or nitrate in water diffuse into the formation) in the long term is not known. UMTRA site studies3 have shown that iron sulfide solids are produced by sulfate reducing bacteria (SRB) during U bioremediation, and some forms of these iron sulfide solids are known to be effective oxidant scavengers, potentially protecting against re-oxidation and thus remobilization of U. This work is investigating the role of iron sulfide solids in the long-term immobilization of reduced U compounds after bioremediation is completed in groundwater local to UMTRA sites. Re-oxidation tests are being performed in packed media columns loaded with both FeS and U solids. High quality mackinawite (FeS), and uraninite (UO2) have been synthesized in our laboratory via a wet chemistry approach. These synthetic materials are expected to mimic the naturally occurring and biogenic materials present in biologically stimulated UMTRA sites. In order to establish the initial conditions of the prepared experimental columns and to compare synthetic and biogenic FeS and UO2, these synthesized materials have been characterized with synchrotron radiation at the Stanford Synchrotron Radiation Lightsource using synchrotron x-ray powder diffraction (SXRD) and extended x-ray absorption fine structure (EXAFS). SXRD data were collected and analyzed with profile fitting to determine lattice parameters and crystallite size for comparison with published values for both biogenic and synthetic materials. This is particularly of interest for UO2, as there is very little information on particle size and lattice parameters for synthetic UO2 in the literature. Profile fitting of the SXRD data for FeS gives lattice parameters of a = b = 3.668 and a mean crystallite size of 5 to 8 nm. Both of these values are in good agreement with published values. For fresh UO2, lattice parameters were determined as a = b = c = 5.4 nm for both freshly synthesized and aged (3 months) UO2 and particle size was determined to be 3.5 nm for fresh UO2 and 5.83 nm for aged UO2. This suggests a growth mechanism for crystallites over time, and an inferred decrease in reactivity.

Diversity and Characterization of Sulfate-Reducing Bacteria in Groundwater at a Uranium Mill Tailings Site

PubMed Central

Chang, Yun-Juan; Peacock, Aaron D.; Long, Philip E.; Stephen, John R.; McKinley, James P.; Macnaughton, Sarah J.; Hussain, A. K. M. Anwar; Saxton, Arnold M.; White, David C.

2001-01-01

Microbially mediated reduction and immobilization of U(VI) to U(IV) plays a role in both natural attenuation and accelerated bioremediation of uranium-contaminated sites. To realize bioremediation potential and accurately predict natural attenuation, it is important to first understand the microbial diversity of such sites. In this paper, the distribution of sulfate-reducing bacteria (SRB) in contaminated groundwater associated with a uranium mill tailings disposal site at Shiprock, N.Mex., was investigated. Two culture-independent analyses were employed: sequencing of clone libraries of PCR-amplified dissimilatory sulfite reductase (DSR) gene fragments and phospholipid fatty acid (PLFA) biomarker analysis. A remarkable diversity among the DSR sequences was revealed, including sequences from δ-Proteobacteria, gram-positive organisms, and the Nitrospira division. PLFA analysis detected at least 52 different mid-chain-branched saturate PLFA and included a high proportion of 10me16:0. Desulfotomaculum and Desulfotomaculum-like sequences were the most dominant DSR genes detected. Those belonging to SRB within δ-Proteobacteria were mainly recovered from low-uranium (≤302 ppb) samples. One Desulfotomaculum-like sequence cluster overwhelmingly dominated high-U (>1,500 ppb) sites. Logistic regression showed a significant influence of uranium concentration over the dominance of this cluster of sequences (P = 0.0001). This strong association indicates that Desulfotomaculum has remarkable tolerance and adaptation to high levels of uranium and suggests the organism's possible involvement in natural attenuation of uranium. The in situ activity level of Desulfotomaculum in uranium-contaminated environments and its comparison to the activities of other SRB and other functional groups should be an important area for future research. PMID:11425735

Complete genome sequence of Anaeromyxobacter sp. Fw109-5, an Anaerobic, Metal-Reducing Bacterium Isolated from a Contaminated Subsurface Environment

DOE PAGES

Hwang, C.; Copeland, A.; Lucas, Susan; ...

2015-01-22

We report the genome sequence of Anaeromyxobacter sp. Fw109-5, isolated from nitrate- and uranium-contaminated subsurface sediment of the Oak Ridge Integrated Field-Scale Subsurface Research Challenge (IFC) site, Oak Ridge Reservation, TN. The bacterium’s genome sequence will elucidate its physiological potential in subsurface sediments undergoing in situ uranium bioremediation and natural attenuation.

Uranium reduction and microbial community development in response to stimulation with different electron donors.

PubMed

Barlett, Melissa; Moon, Hee Sun; Peacock, Aaron A; Hedrick, David B; Williams, Kenneth H; Long, Philip E; Lovley, Derek; Jaffe, Peter R

2012-07-01

Stimulating microbial reduction of soluble U(VI) to less soluble U(IV) shows promise as an in situ bioremediation strategy for uranium contaminated groundwater, but the optimal electron donors for promoting this process have yet to be identified. The purpose of this study was to better understand how the addition of various electron donors to uranium-contaminated subsurface sediments affected U(VI) reduction and the composition of the microbial community. The simple electron donors, acetate or lactate, or the more complex donors, hydrogen-release compound (HRC) or vegetable oil, were added to the sediments incubated in flow-through columns. The composition of the microbial communities was evaluated with quantitative PCR probing specific 16S rRNA genes and functional genes, phospholipid fatty acid analysis, and clone libraries. All the electron donors promoted U(VI) removal, even though the composition of the microbial communities was different with each donor. In general, the overall biomass, rather than the specific bacterial species, was the factor most related to U(VI) removal. Vegetable oil and HRC were more effective in stimulating U(VI) removal than acetate. These results suggest that the addition of more complex organic electron donors could be an excellent option for in situ bioremediation of uranium-contaminated groundwater.

Bacterial Community Succession During in situ Uranium Bioremediation: Spatial Similarities Along Controlled Flow Paths

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

Hwang, Chiachi; Wu, Weimin; Gentry, Terry J.

2009-05-22

Bacterial community succession was investigated in a field-scale subsurface reactor formed by a series of wells that received weekly ethanol additions to re-circulating groundwater. Ethanol additions stimulated denitrification, metal reduction, sulfate reduction, and U(VI) reduction to sparingly soluble U(IV). Clone libraries of SSU rRNA gene sequences from groundwater samples enabled tracking of spatial and temporal changes over a 1.5 y period. Analyses showed that the communities changed in a manner consistent with geochemical variations that occurred along temporal and spatial scales. Canonical correspondence analysis revealed that the levels of nitrate, uranium, sulfide, sulfate, and ethanol strongly correlated with particular bacterialmore » populations. As sulfate and U(VI) levels declined, sequences representative of sulfate-reducers and metal-reducers were detected at high levels. Ultimately, sequences associated with sulfate-reducing populations predominated, and sulfate levels declined as U(VI) remained at low levels. When engineering controls were compared to the population variation via canonical ordination, changes could be related to dissolved oxygen control and ethanol addition. The data also indicated that the indigenous populations responded differently to stimulation for bio-reduction; however, the two bio-stimulated communities became more similar after different transitions in an idiosyncratic manner. The strong associations between particular environmental variables and certain populations provide insight into the establishment of practical and successful remediation strategies in radionuclide-contaminated environments with respect to engineering controls and microbial ecology.« less

Uranium removal from a contaminated effluent using a combined microbial and nanoparticle system.

PubMed

Baiget, Mar; Constantí, Magda; López, M Teresa; Medina, Francesc

2013-09-25

Reduction of soluble uranium(VI) to insoluble uranium(IV) for remediating a uranium-contaminated effluent (EF-03) was examined using a biotic and abiotic integrated system. Shewanella putrefaciens was first used and reduced U(VI) in a synthetic medium but not in the EF-03 effluent sample. Subsequently the growth of autochthonous microorganisms was stimulated with lactate. When lactate was supported on active carbon 77% U(VI) was removed in 4 days. Separately, iron nanoparticles that were 50 nm in diameter reduced U(VI) by 60% in 4 hours. The efficiency of uranium(VI) removal was improved to 96% in 30 min by using a system consisting of lactate and iron nanoparticles immobilized on active carbon. Lactate also stimulated the growth of potential uranium-reducing microorganisms in the EF-03 sample. This system can be efficiently used for the bioremediation of uranium-contaminated effluents. Copyright © 2013 Elsevier B.V. All rights reserved.

Simulation of in situ uranium bioremediation with slow-release organic amendment injection

NASA Astrophysics Data System (ADS)

Zhang, F.; Parker, J.; Ye, M.; Tang, G.; Wu, W.; Mehlhorn, T.; Gihring, T. M.; Schadt, C.; Watson, D. B.; Brooks, S. C.

2010-12-01

In situ bioremediation of a highly uranium-contaminated gravel aquifer with a slow-release electron donor (emulsified edible oil) has been investigated at the US DOE Oak Ridge Integrated Field Research Challenge (ORIFRC) site in east Tennessee. Groundwater at the study location has pH ~6.7 and contains high concentrations of U (5-6 μM), sulfate (1.0-1.2) mM and Ca (3-4 mM). Diluted emulsified oil (20% solution) was injected into three injection wells within 1.5 hrs. Geochemical analysis of site groundwater demonstrated the sequential reduction of nitrate, Mn, Fe(III) and sulfate. The oil was degraded by indigenous microorganisms with acetate as a major product. Rapid removal of U(VI) from the aqueous phase occurred concurrently with acetate production and sulfate reduction. The field test data were analyzed using a reaction network with a kinetic model for lipid hydrolysis and glycerol fermentation and equilibrium reactions representing microbial reduction of sulfate, nitrate, iron, uranium, manganese and carbon dioxide based on the thermodynamic approach of Istok et al. (2010) using the parallelized HGC5 code. Model-simulated chemical concentrations and relative abundance of functional microbial populations are compared with field measurements. Application of the thermodynamically-based modeling approach instead of the widely used multi-Monod kinetic rate law to formulate bioreduction reactions substantially reduces the number of reaction parameters that need to be calibrated thus facilitating a more comprehensive representation of microbial community dynamics. The model developed through this study is expected to aid the design of future bioremediation strategies for the site.

Microbial Functional Gene Diversity with a Shift of Subsurface Redox Conditions during In Situ Uranium Reduction

PubMed Central

Liang, Yuting; Van Nostrand, Joy D.; N′Guessan, Lucie A.; Peacock, Aaron D.; Deng, Ye; Long, Philip E.; Resch, C. Tom; Wu, Liyou; He, Zhili; Li, Guanghe; Hazen, Terry C.; Lovley, Derek R.

2012-01-01

To better understand the microbial functional diversity changes with subsurface redox conditions during in situ uranium bioremediation, key functional genes were studied with GeoChip, a comprehensive functional gene microarray, in field experiments at a uranium mill tailings remedial action (UMTRA) site (Rifle, CO). The results indicated that functional microbial communities altered with a shift in the dominant metabolic process, as documented by hierarchical cluster and ordination analyses of all detected functional genes. The abundance of dsrAB genes (dissimilatory sulfite reductase genes) and methane generation-related mcr genes (methyl coenzyme M reductase coding genes) increased when redox conditions shifted from Fe-reducing to sulfate-reducing conditions. The cytochrome genes detected were primarily from Geobacter sp. and decreased with lower subsurface redox conditions. Statistical analysis of environmental parameters and functional genes indicated that acetate, U(VI), and redox potential (Eh) were the most significant geochemical variables linked to microbial functional gene structures, and changes in microbial functional diversity were strongly related to the dominant terminal electron-accepting process following acetate addition. The study indicates that the microbial functional genes clearly reflect the in situ redox conditions and the dominant microbial processes, which in turn influence uranium bioreduction. Microbial functional genes thus could be very useful for tracking microbial community structure and dynamics during bioremediation. PMID:22327592

Responses of microbial community functional structures to pilot-scale uranium in situ bioremediation

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

Xu, M.; Wu, W.-M.; Wu, L.

2010-02-15

A pilot-scale field test system with an inner loop nested within an outer loop was constructed for in situ U(VI) bioremediation at a US Department of Energy site, Oak Ridge, TN. The outer loop was used for hydrological protection of the inner loop where ethanol was injected for biostimulation of microorganisms for U(VI) reduction/immobilization. After 2 years of biostimulation with ethanol, U(VI) levels were reduced to below drinking water standard (<30 {micro}gl{sup -1}) in the inner loop monitoring wells. To elucidate the microbial community structure and functions under in situ uranium bioremediation conditions, we used a comprehensive functional gene arraymore » (GeoChip) to examine the microbial functional gene composition of the sediment samples collected from both inner and outer loop wells. Our study results showed that distinct microbial communities were established in the inner loop wells. Also, higher microbial functional gene number, diversity and abundance were observed in the inner loop wells than the outer loop wells. In addition, metal-reducing bacteria, such as Desulfovibrio, Geobacter, Anaeromyxobacter and Shewanella, and other bacteria, for example, Rhodopseudomonas and Pseudomonas, are highly abundant in the inner loop wells. Finally, the richness and abundance of microbial functional genes were highly correlated with the mean travel time of groundwater from the inner loop injection well, pH and sulfate concentration in groundwater. These results suggest that the indigenous microbial communities can be successfully stimulated for U bioremediation in the groundwater ecosystem, and their structure and performance can be manipulated or optimized by adjusting geochemical and hydrological conditions.« less

Molecular analysis of phosphate limitation in Geobacteraceae during the bioremediation of a uranium-contaminated aquifer

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

N'Guessan, L.A.; Elifantz, H.; Nevin, K.P.

2009-09-01

Nutrient limitation is an environmental stress that may reduce the effectiveness of bioremediation strategies, especially when the contaminants are organic compounds or when organic compounds are added to promote microbial activities such as metal reduction. Genes indicative of phosphate-limitation were identified via microarray analysis of chemostat cultures of Geobacter sulfureducens. This analysis revealed that genes in the pst-pho operon, which is associated with a high affinity phosphate uptake system in other microorganisms, had significantly higher transcript abundance under phosphate-limiting conditions, with the genes pstB and phoU the most up-regulated. Quantitative PCR analysis of pstB and phoU transcript levels in G.more » sulfurreducens grown in chemostats demonstrated that the expression of these genes increased when phosphate was removed from the culture medium. Transcripts of pstB and phoU within the subsurface Geobacter species predominating during an in situ uranium bioremediation field experiment were more abundant than in chemostat cultures of G. sulfurreducens that were not limited for phosphate. Addition of phosphate to incubations of subsurface sediments did not stimulate dissimilatory metal reduction. The added phosphate was rapidly adsorbed onto the sediments. The results demonstrate that Geobacter species can effectively reduce U(VI) even when experiencing suboptimal phosphate concentrations and that increasing phosphate availability with phosphate additions is difficult to achieve due to the high reactivity of this compound. This transcript-based approach developed for diagnosing phosphate limitation should be applicable to assessing the potential need for additional phosphate in other bioremediation processes.« less

Molecular Analysis of Phosphate Limitation in Geobacteraceae During the Bioremediation of a Uranium-Contaminated Aquifer

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

N'Guessan, A. Lucie; Elifantz, H.; Nevin, Kelly P.

2010-02-01

Nutrient limitation is an environmental stress that may reduce the effectiveness of bioremediation strategies, especially when the contaminants are organic compounds or when organic compounds are added to promote microbial activities such as metal reduction. Genes indicative of phosphate-limitation were identified via microarray analysis of chemostat cultures of Geobacter sulfureducens. This analysis revealed that genes in the pst-pho operon, which is associated with a high affinity phosphate uptake system in other microorganisms, had significantly higher transcript abundance under phosphate-limiting conditions, with the genes pstB and phoU the most up-regulated. Quantitative PCR analysis of pstB and phoU transcript levels in G.more » sulfurreducens grown in chemostats demonstrated that the expression of these genes increased when phosphate was removed from the culture medium. Transcripts of pstB and phoU within the subsurface Geobacter species predominating during an in situ uranium bioremediation field experiment were more abundant than in chemostat cultures of G. sulfurreducens that were not limited for phosphate. Addition of phosphate to incubations of subsurface sediments did not stimulate dissimilatory metal reduction. The added phosphate was rapidly adsorbed onto the sediments. The results demonstrate that Geobacter species can effectively reduce U(VI) even when experiencing suboptimal phosphate concentrations and that increasing phosphate availability with phosphate additions is difficult to achieve due to the high reactivity of this compound. This transcript-based approach developed for diagnosing phosphate limitation should be applicable to assessing the potential need for additional phosphate in other bioremediation processes.« less

Molecular analysis of phosphate limitation in Geobacteraceae during the bioremediation of a uranium-contaminated aquifer

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

N'Guessan, A. Lucie; Elifantz, H.; Nevin, Kelly P.

2010-01-10

Nutrient limitation is an environmental stress that may reduce the effectiveness of bioremediation strategies, especially when the contaminants are organic compounds or when organic compounds are added to promote microbial activities such as metal reduction. Genes indicative of phosphatelimitation were identified by microarray analysis of chemostat cultures of Geobacter sulfureducens. This analysis revealed that genes in the pst-pho operon, which is associated with a high-affinity phosphate uptake system in other microorganisms, had significantly higher transcript abundance under phosphate-limiting conditions, with the genes pstB and phoU upregulated the most. Quantitative PCR analysis of pstB and phoU transcript levels in G. sulfurreducensmore » grown in chemostats demonstrated that the expression of these genes increased when phosphate was removed from the culture medium. Transcripts of pstB and phoU within the subsurface Geobacter species predominating during an in situ uranium-bioremediation field experiment were more abundant than in chemostat cultures of G. sulfurreducens that were not limited for phosphate. Addition of phosphate to incubations of subsurface sediments did not stimulate dissimilatory metal reduction. The added phosphate was rapidly adsorbed onto the sediments. The results demonstrate that Geobacter species can effectively reduce U(VI) even when experiencing suboptimal phosphate concentrations and that increasing phosphate availability with phosphate additions is difficult to achieve because of the high reactivity of this compound. This transcript-based approach developed for diagnosing phosphate limitation should be applicable to assessing the potential need for additional phosphate in other bioremediation processes.« less

Geobacter strains that use alternate organic compounds, methods of making, and methods of use thereof

DOEpatents

Lovley, Derek R.; Summers, Zarath Morgan; Haveman, Shelley Annette; Izallalen, Mounir

2016-03-01

In preferred embodiments, the present invention provides new isolated strains of a Geobacter species that are capable of using a carbon source that is selected from C.sub.3 to C.sub.12 organic compounds selected from pyruvate or metabolic precursors of pyruvate as an electron donor in metabolism and in subsequent energy production. The wild type strain of the microorganisms has been shown to be unable to use these C.sub.3 to C.sub.12 organic compounds as electron donors. The inventive strains of microorganisms are useful for improving bioremediation applications, including in situ bioremediation (including uranium bioremediation and halogenated solvent bioremediation), microbial fuel cells, power generation from small and large-scale waste facilities (e.g., biomass waste from dairy, agriculture, food processing, brewery, or vintner industries, etc.) using microbial fuel cells, and other applications of microbial fuel cells, including, but not limited to, improved electrical power supplies for environmental sensors, electronic devices, and electric vehicles.

Variably Saturated Flow and Multicomponent Biogeochemical Reactive Transport Modeling of a Uranium Bioremediation Field Experiment

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

Yabusaki, Steven B.; Fang, Yilin; Williams, Kenneth H.

2011-11-01

Field experiments at a former uranium mill tailings site have identified the potential for stimulating indigenous bacteria to catalyze the conversion of aqueous uranium in the +6 oxidation state to immobile solid-associated uranium in the +4 oxidation state. This effectively removes uranium from solution resulting in groundwater concentrations below actionable standards. Three-dimensional, coupled variably-saturated flow and biogeochemical reactive transport modeling of a 2008 in situ uranium bioremediation field experiment is used to better understand the interplay of transport rates and biogeochemical reaction rates that determine the location and magnitude of key reaction products. A comprehensive reaction network, developed largely throughmore » previous 1-D modeling studies, was used to simulate the impacts on uranium behavior of pulsed acetate amendment, seasonal water table variation, spatially-variable physical (hydraulic conductivity, porosity) and geochemical (reactive surface area) material properties. A principal challenge is the mechanistic representation of biologically-mediated terminal electron acceptor process (TEAP) reactions whose products significantly alter geochemical controls on uranium mobility through increases in pH, alkalinity, exchangeable cations, and highly reactive reduction products. In general, these simulations of the 2008 Big Rusty acetate biostimulation field experiment in Rifle, Colorado confirmed previously identified behaviors including (1) initial dominance by iron reducing bacteria that concomitantly reduce aqueous U(VI), (2) sulfate reducing bacteria that become dominant after {approx}30 days and outcompete iron reducers for the acetate electron donor, (3) continuing iron-reducer activity and U(VI) bioreduction during dominantly sulfate reducing conditions, and (4) lower apparent U(VI) removal from groundwater during dominantly sulfate reducing conditions. New knowledge on simultaneously active metal and sulfate reducers has been incorporated into the modeling. In this case, an initially small population of slow growing sulfate reducers is active from the initiation of biostimulation. Three-dimensional, variably saturated flow modeling was used to address impacts of a falling water table during acetate injection. These impacts included a significant reduction in aquifer saturated thickness and isolation of residual reactants and products, as well as unmitigated uranium, in the newly unsaturated vadose zone. High permeability sandy gravel structures resulted in locally high flow rates in the vicinity of injection wells that increased acetate dilution. In downgradient locations, these structures created preferential flow paths for acetate delivery that enhanced local zones of TEAP reactivity and subsidiary reactions. Conversely, smaller transport rates associated with the lower permeability lithofacies (e.g., fine) and vadose zone were shown to limit acetate access and reaction. Once accessed by acetate, however, these same zones limited subsequent acetate dilution and provided longer residence times that resulted in higher concentrations of TEAP products when terminal electron donors and acceptors were not limiting. Finally, facies-based porosity and reactive surface area variations were shown to affect aqueous uranium concentration distributions; however, the ranges were sufficiently small to preserve general trends. Large computer memory and high computational performance were required to simulate the detailed coupled process models for multiple biogeochemical components in highly resolved heterogeneous materials for the 110-day field experiment and 50 days of post-biostimulation behavior. In this case, a highly-scalable subsurface simulator operating on 128 processor cores for 12 hours was used to simulate each realization. An equivalent simulation without parallel processing would have taken 60 days, assuming sufficient memory was available.« less

Uranium (U)-Tolerant Bacterial Diversity from U Ore Deposit of Domiasiat in North-East India and Its Prospective Utilisation in Bioremediation

PubMed Central

Kumar, Rakshak; Nongkhlaw, Macmillan; Acharya, Celin; Joshi, Santa Ram

2013-01-01

Uranium (U)-tolerant aerobic chemo-heterotrophic bacteria were isolated from the sub-surface soils of U-rich deposits in Domiasiat, North East India. The bacterial community explored at molecular level by amplified ribosomal DNA restriction analysis (ARDRA) resulted in 51 distinct phylotypes. Bacterial community assemblages at the U mining site with the concentration of U ranging from 20 to 100 ppm, were found to be most diverse. Representative bacteria analysed by 16S rRNA gene sequencing were affiliated to Firmicutes (51%), Gammaproteobacteria (26%), Actinobacteria (11%), Bacteroidetes (10%) and Betaproteobacteria (2%). Representative strains removed more than 90% and 53% of U from 100 μM and 2 mM uranyl nitrate solutions, respectively, at pH 3.5 within 10 min of exposure and the activity was retained until 24 h. Overall, 76% of characterized isolates possessed phosphatase enzyme and 53% had PIB-type ATPase genes. This study generated baseline information on the diverse indigenous U-tolerant bacteria which could serve as an indicator to estimate the environmental impact expected to be caused by mining in the future. Also, these natural isolates efficient in uranium binding and harbouring phosphatase enzyme and metal-transporting genes could possibly play a vital role in the bioremediation of metal-/radionuclide-contaminated environments. PMID:23080407

Network succession reveals the importance of competition in response to emulsified vegetable oil amendment for uranium bioremediation: Competition in bioremediation system

DOE PAGES

Deng, Ye; Zhang, Ping; Qin, Yujia; ...

2015-08-11

When trying to discern network interactions among different species/populations in microbial communities interests have been evoked in recent years, but little information is available about temporal dynamics of microbial network interactions in response to environmental perturbations. We modified the random matrix theory-based network approach to discern network succession in groundwater microbial communities in response to emulsified vegetable oil (EVO) amendment for uranium bioremediation. Groundwater microbial communities from one control and seven monitor wells were analysed with a functional gene array (GeoChip 3.0), and functional molecular ecological networks (fMENs) at different time points were reconstructed. Our results showed that the networkmore » interactions were dramatically altered by EVO amendment. Dynamic and resilient succession was evident: fairly simple at the initial stage (Day 0), increasingly complex at the middle period (Days 4, 17, 31), most complex at Day 80, and then decreasingly complex at a later stage (140–269 days). Unlike previous studies in other habitats, negative interactions predominated in a time-series fMEN, suggesting strong competition among different microbial species in the groundwater systems after EVO injection. In particular, several keystone sulfate-reducing bacteria showed strong negative interactions with their network neighbours. These results provide mechanistic understanding of the decreased phylogenetic diversity during environmental perturbations.« less

Raoultella sp. SM1, a novel iron-reducing and uranium-precipitating strain.

PubMed

Sklodowska, Aleksandra; Mielnicki, Sebastian; Drewniak, Lukasz

2018-03-01

The main aim of this study was the characterisation of novel Raoutella isolate, an iron-reducing and uranium-precipitating strain, originating from microbial mats occurring in the sediments of a closed down uranium mine in Kowary (SW Poland). Characterisation was done in the context of its potential role in the functioning of these mats and the possibility to use them in uranium removal/recovery processes. In our experiment, we observed the biological precipitation of iron and uranium's secondary minerals containing oxygen, potassium, sodium and phosphor, which were identified as ningyoite-like minerals. The isolated strain, Raoultella sp. SM1, was also able to dissimilatory reduce iron (III) and uranium (VI) in the presence of citrate as an electron donor. Our studies allowed us to characterise a new strain which may be used as a model microorganism in the study of Fe and U respiratory processes and which may be useful in the bioremediation of uranium-contaminated waters and sediments. During this process, uranium may be immobilised in ningyoite-like minerals and can then be recovered in nano/micro-particle form, which may be easily transformed to uraninite. Copyright © 2017 Elsevier Ltd. All rights reserved.

Subsurface clade of Geobacteraceae that predominates in a diversity of Fe(III)-reducing subsurface environments

USGS Publications Warehouse

Holmes, Dawn E.; O'Neil, Regina A.; Vrionis, Helen A.; N'Guessan, Lucie A.; Ortiz-Bernad, Irene; Larrahondo, Maria J.; Adams, Lorrie A.; Ward, Joy A.; Nicoll , Julie S.; Nevin, Kelly P.; Chavan, Milind A.; Johnson, Jessica P.; Long, Philip E.; Lovely, Derek R.

2007-01-01

There are distinct differences in the physiology of Geobacter species available in pure culture. Therefore, to understand the ecology of Geobacter species in subsurface environments, it is important to know which species predominate. Clone libraries were assembled with 16S rRNA genes and transcripts amplified from three subsurface environments in which Geobacter species are known to be important members of the microbial community: (1) a uranium-contaminated aquifer located in Rifle, CO, USA undergoing in situ bioremediation; (2) an acetate-impacted aquifer that serves as an analog for the long-term acetate amendments proposed for in situ uranium bioremediation and (3) a petroleum-contaminated aquifer in which Geobacter species play a role in the oxidation of aromatic hydrocarbons coupled with the reduction of Fe(III). The majority of Geobacteraceae 16S rRNA sequences found in these environments clustered in a phylogenetically coherent subsurface clade, which also contains a number of Geobacter species isolated from subsurface environments. Concatamers constructed with 43 Geobacter genes amplified from these sites also clustered within this subsurface clade. 16S rRNA transcript and gene sequences in the sediments and groundwater at the Rifle site were highly similar, suggesting that sampling groundwater via monitoring wells can recover the most active Geobacter species. These results suggest that further study of Geobacter species in the subsurface clade is necessary to accurately model the behavior of Geobacter species during subsurface bioremediation of metal and organic contaminants.

A procedure for quantitation of total oxidized uranium for bioremediation studies

USGS Publications Warehouse

Elias, Dwayne A.; Senko, John M.; Krumholz, Lee R.

2003-01-01

A procedure was developed for the quantitation of complexed U(VI) during studies on U(VI) bioremediation. These studies typically involve conversion of soluble or complexed U(VI) (oxidized) to U(IV) (the reduced form which is much less soluble). Since U(VI) freely exchanges between material adsorbed to the solid phase and the dissolved phase, uranium bioremediation experiments require a mass balance of U in both its soluble and adsorbed forms as well as in the reduced sediment bound phase. We set out to optimize a procedure for extraction and quantitation of sediment bound U(VI). Various extractant volumes to sediment ratios were tested and it was found that between 1:1 to 8:1 ratios (v/w) there was a steady increase in U(VI) recovered, but no change with further increases in v/w ratio.Various strengths of NaHCO3, Na-EDTA, and Na-citrate were used to evaluate complexed U(VI) recovery, while the efficiency of a single versus repeated extraction steps was compared with synthesized uranyl-phosphate and uranyl-hydroxide. Total recovery with 1 M NaHCO3 was 95.7% and 97.9% from uranyl-phosphate and uranyl-hydroxide, respectively, compared to 80.7% and 89.9% using 450 mM NaHCO3. Performing the procedure once yielded an efficiency of 81.1% and 92.3% for uranyl-phosphate and uranyl-hydroxide, respectively, as compared to three times. All other extractants yielded 7.9–82.0% in both experiments.

Geobacter strains that use alternate organic compounds, methods of making, and methods of use thereof

DOEpatents

Lovley, Derek R; Summers, Zarath Morgan; Haveman, Shelley Annette; Izallalen, Mounir

2013-12-03

In preferred embodiments, the present invention provides new isolated strains of Geobacter species that are capable of using a carbon source that is selected from C.sub.3 to C.sub.12 organic compounds selected from pyruvate or metabolic precursors of pyruvate as an electron donor in metabolism and in subsequent energy production. In other aspects, other preferred embodiments of the present invention include methods of making such strains and methods of using such strains. In general, the wild type strain of the microorganisms has been shown to be unable to use these C.sub.3 to C.sub.12 organic compounds as electron donors in metabolic steps such as the reduction of metallic ions. The inventive strains of microorganisms are useful improving bioremediation applications, including in situ bioremediation (including uranium bioremediation and halogenated solvent bioremediation), microbial fuel cells, power generation from small and large-scale waste facilities (e.g., biomass waste from dairy, agriculture, food processing, brewery, or vintner industries, etc.) using microbial fuel cells, and other applications of microbial fuel cells, including, but not limited to, improved electrical power supplies for environmental sensors, electronic sensors, and electric vehicles.

Sustained removal of uranium from contaminated groundwater following stimulation of dissimilatory metal reduction.

PubMed

N'Guessan, A Lucie; Vrionis, Helen A; Resch, Charles T; Long, Philip E; Lovley, Derek R

2008-04-15

Previous field studies on in situ bioremediation of uranium-contaminated groundwater in an aquifer in Rifle, Colorado identified two distinct phases following the addition of acetate to stimulate microbial respiration. In phase I, Geobacter species are the predominant organisms, Fe(III) is reduced, and microbial reduction of soluble U(VI) to insoluble U(IV) removes uranium from the groundwater. In phase II, Fe(III) is depleted, sulfate is reduced, and sulfate-reducing bacteria predominate. Long-term monitoring revealed an unexpected third phase during which U(VI) removal continues even after acetate additions are stopped. All three of these phases were successfully reproduced in flow-through sediment columns. When sediments from the third phase were heat sterilized, the capacity for U(VI) removal was lost. In the live sediments U(VI) removed from the groundwater was recovered as U(VI) in the sediments. This contrasts to the recovery of U(IV) in sediments resulting from the reduction of U(VI) to U(IV) during the Fe(III) reduction phase in acetate-amended sediments. Analysis of 16S rRNA gene sequences in the sediments in which U(VI) was being adsorbed indicated that members of the Firmicutes were the predominant organisms whereas no Firmicutes sequences were detected in background sediments which did not have the capacity to sorb U(VI), suggesting that the U(VI) adsorption might be due to the presence of these living organisms or at least their intact cell components. This unexpected enhanced adsorption of U(VI) onto sediments following the stimulation of microbial growth in the subsurface may potentially enhance the cost effectiveness of in situ uranium bioremediation.

Sensitivity Analysis and Parameter Estimation for a Reactive Transport Model of Uranium Bioremediation

NASA Astrophysics Data System (ADS)

Meyer, P. D.; Yabusaki, S.; Curtis, G. P.; Ye, M.; Fang, Y.

2011-12-01

A three-dimensional, variably-saturated flow and multicomponent biogeochemical reactive transport model of uranium bioremediation was used to generate synthetic data . The 3-D model was based on a field experiment at the U.S. Dept. of Energy Rifle Integrated Field Research Challenge site that used acetate biostimulation of indigenous metal reducing bacteria to catalyze the conversion of aqueous uranium in the +6 oxidation state to immobile solid-associated uranium in the +4 oxidation state. A key assumption in past modeling studies at this site was that a comprehensive reaction network could be developed largely through one-dimensional modeling. Sensitivity analyses and parameter estimation were completed for a 1-D reactive transport model abstracted from the 3-D model to test this assumption, to identify parameters with the greatest potential to contribute to model predictive uncertainty, and to evaluate model structure and data limitations. Results showed that sensitivities of key biogeochemical concentrations varied in space and time, that model nonlinearities and/or parameter interactions have a significant impact on calculated sensitivities, and that the complexity of the model's representation of processes affecting Fe(II) in the system may make it difficult to correctly attribute observed Fe(II) behavior to modeled processes. Non-uniformity of the 3-D simulated groundwater flux and averaging of the 3-D synthetic data for use as calibration targets in the 1-D modeling resulted in systematic errors in the 1-D model parameter estimates and outputs. This occurred despite using the same reaction network for 1-D modeling as used in the data-generating 3-D model. Predictive uncertainty of the 1-D model appeared to be significantly underestimated by linear parameter uncertainty estimates.

Microfluidic Experiments Studying Pore Scale Interactions of Microbes and Geochemistry

NASA Astrophysics Data System (ADS)

Chen, M.; Kocar, B. D.

2016-12-01

Understanding how physical phenomena, chemical reactions, and microbial behavior interact at the pore-scale is crucial to understanding larger scale trends in groundwater chemistry. Recent studies illustrate the utility of microfluidic devices for illuminating pore-scale physical-biogeochemical processes and their control(s) on the cycling of iron, uranium, and other important elements 1-3. These experimental systems are ideal for examining geochemical reactions mediated by microbes, which include processes governed by complex biological phenomenon (e.g. biofilm formation, etc.)4. We present results of microfluidic experiments using a model metal reducing bacteria and varying pore geometries, exploring the limitations of the microorganisms' ability to access tight pore spaces, and examining coupled biogeochemical-physical controls on the cycling of redox sensitive metals. Experimental results will provide an enhanced understanding of coupled physical-biogeochemical processes transpiring at the pore-scale, and will constrain and compliment continuum models used to predict and describe the subsurface cycling of redox-sensitive elements5. 1. Vrionis, H. A. et al. Microbiological and geochemical heterogeneity in an in situ uranium bioremediation field site. Appl. Environ. Microbiol. 71, 6308-6318 (2005). 2. Pearce, C. I. et al. Pore-scale characterization of biogeochemical controls on iron and uranium speciation under flow conditions. Environ. Sci. Technol. 46, 7992-8000 (2012). 3. Zhang, C., Liu, C. & Shi, Z. Micromodel investigation of transport effect on the kinetics of reductive dissolution of hematite. Environ. Sci. Technol. 47, 4131-4139 (2013). 4. Ginn, T. R. et al. Processes in microbial transport in the natural subsurface. Adv. Water Resour. 25, 1017-1042 (2002). 5. Scheibe, T. D. et al. Coupling a genome-scale metabolic model with a reactive transport model to describe in situ uranium bioremediation. Microb. Biotechnol. 2, 274-286 (2009).

Enhanced uranium immobilization and reduction by Geobacter sulfurreducens biofilms.

PubMed

Cologgi, Dena L; Speers, Allison M; Bullard, Blair A; Kelly, Shelly D; Reguera, Gemma

2014-11-01

Biofilms formed by dissimilatory metal reducers are of interest to develop permeable biobarriers for the immobilization of soluble contaminants such as uranium. Here we show that biofilms of the model uranium-reducing bacterium Geobacter sulfurreducens immobilized substantially more U(VI) than planktonic cells and did so for longer periods of time, reductively precipitating it to a mononuclear U(IV) phase involving carbon ligands. The biofilms also tolerated high and otherwise toxic concentrations (up to 5 mM) of uranium, consistent with a respiratory strategy that also protected the cells from uranium toxicity. The enhanced ability of the biofilms to immobilize uranium correlated only partially with the biofilm biomass and thickness and depended greatly on the area of the biofilm exposed to the soluble contaminant. In contrast, uranium reduction depended on the expression of Geobacter conductive pili and, to a lesser extent, on the presence of the c cytochrome OmcZ in the biofilm matrix. The results support a model in which the electroactive biofilm matrix immobilizes and reduces the uranium in the top stratum. This mechanism prevents the permeation and mineralization of uranium in the cell envelope, thereby preserving essential cellular functions and enhancing the catalytic capacity of Geobacter cells to reduce uranium. Hence, the biofilms provide cells with a physically and chemically protected environment for the sustained immobilization and reduction of uranium that is of interest for the development of improved strategies for the in situ bioremediation of environments impacted by uranium contamination. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Enhanced Uranium Immobilization and Reduction by Geobacter sulfurreducens Biofilms

PubMed Central

Cologgi, Dena L.; Speers, Allison M.; Bullard, Blair A.; Kelly, Shelly D.

2014-01-01

Biofilms formed by dissimilatory metal reducers are of interest to develop permeable biobarriers for the immobilization of soluble contaminants such as uranium. Here we show that biofilms of the model uranium-reducing bacterium Geobacter sulfurreducens immobilized substantially more U(VI) than planktonic cells and did so for longer periods of time, reductively precipitating it to a mononuclear U(IV) phase involving carbon ligands. The biofilms also tolerated high and otherwise toxic concentrations (up to 5 mM) of uranium, consistent with a respiratory strategy that also protected the cells from uranium toxicity. The enhanced ability of the biofilms to immobilize uranium correlated only partially with the biofilm biomass and thickness and depended greatly on the area of the biofilm exposed to the soluble contaminant. In contrast, uranium reduction depended on the expression of Geobacter conductive pili and, to a lesser extent, on the presence of the c cytochrome OmcZ in the biofilm matrix. The results support a model in which the electroactive biofilm matrix immobilizes and reduces the uranium in the top stratum. This mechanism prevents the permeation and mineralization of uranium in the cell envelope, thereby preserving essential cellular functions and enhancing the catalytic capacity of Geobacter cells to reduce uranium. Hence, the biofilms provide cells with a physically and chemically protected environment for the sustained immobilization and reduction of uranium that is of interest for the development of improved strategies for the in situ bioremediation of environments impacted by uranium contamination. PMID:25128347

Genome-scale dynamic modeling of the competition between Rhodoferax and Geobacter in anoxic subsurface environments.

PubMed

Zhuang, Kai; Izallalen, Mounir; Mouser, Paula; Richter, Hanno; Risso, Carla; Mahadevan, Radhakrishnan; Lovley, Derek R

2011-02-01

The advent of rapid complete genome sequencing, and the potential to capture this information in genome-scale metabolic models, provide the possibility of comprehensively modeling microbial community interactions. For example, Rhodoferax and Geobacter species are acetate-oxidizing Fe(III)-reducers that compete in anoxic subsurface environments and this competition may have an influence on the in situ bioremediation of uranium-contaminated groundwater. Therefore, genome-scale models of Geobacter sulfurreducens and Rhodoferax ferrireducens were used to evaluate how Geobacter and Rhodoferax species might compete under diverse conditions found in a uranium-contaminated aquifer in Rifle, CO. The model predicted that at the low rates of acetate flux expected under natural conditions at the site, Rhodoferax will outcompete Geobacter as long as sufficient ammonium is available. The model also predicted that when high concentrations of acetate are added during in situ bioremediation, Geobacter species would predominate, consistent with field-scale observations. This can be attributed to the higher expected growth yields of Rhodoferax and the ability of Geobacter to fix nitrogen. The modeling predicted relative proportions of Geobacter and Rhodoferax in geochemically distinct zones of the Rifle site that were comparable to those that were previously documented with molecular techniques. The model also predicted that under nitrogen fixation, higher carbon and electron fluxes would be diverted toward respiration rather than biomass formation in Geobacter, providing a potential explanation for enhanced in situ U(VI) reduction in low-ammonium zones. These results show that genome-scale modeling can be a useful tool for predicting microbial interactions in subsurface environments and shows promise for designing bioremediation strategies.

Redox behavior of uranium at the nanoporous aluminum oxide-water interface: implications for uranium remediation.

PubMed

Jung, Hun Bok; Boyanov, Maxim I; Konishi, Hiromi; Sun, Yubing; Mishra, Bhoopesh; Kemner, Kenneth M; Roden, Eric E; Xu, Huifang

2012-07-03

Sorption-desorption experiments show that the majority (ca. 80-90%) of U(VI) presorbed to mesoporous and nanoporous alumina could not be released by extended (2 week) extraction with 50 mM NaHCO(3) in contrast with non-nanoporous α alumina. The extent of reduction of U(VI) presorbed to aluminum oxides was semiquantitatively estimated by comparing the percentages of uranium desorbed by anoxic sodium bicarbonate between AH(2)DS-reacted and unreacted control samples. X-ray absorption spectroscopy confirmed that U(VI) presorbed to non-nanoporous alumina was rapidly and completely reduced to nanoparticulate uraninite by AH(2)DS, whereas reduction of U(VI) presorbed to nanoporous alumina was slow and incomplete (<5% reduction after 1 week). The observed nanopore size-dependent redox behavior of U has important implications in developing efficient remediation techniques for the subsurface uranium contamination because the efficiency of in situ bioremediation depends on how effectively and rapidly U(VI) bound to sediment or soil can be converted to an immobile phase.

Spatial And Temporal Distribution Of Microbial Communities In A TCE DNAPL Site: SABRE Field Studies

EPA Science Inventory

The SABRE (Source Area BioREmediation) project was conducted to evaluate accelerated anaerobic bioremediation of chlorinated solvents in areas of high concentration, such as DNAPL source areas. To study performance of this technology, a test cell was constructed with a longitudi...

Uranium Biominerals Precipitated by an Environmental Isolate of Serratia under Anaerobic Conditions.

PubMed

Newsome, Laura; Morris, Katherine; Lloyd, Jonathan R

2015-01-01

Stimulating the microbially-mediated precipitation of uranium biominerals may be used to treat groundwater contamination at nuclear sites. The majority of studies to date have focussed on the reductive precipitation of uranium as U(IV) by U(VI)- and Fe(III)-reducing bacteria such as Geobacter and Shewanella species, although other mechanisms of uranium removal from solution can occur, including the precipitation of uranyl phosphates via bacterial phosphatase activity. Here we present the results of uranium biomineralisation experiments using an isolate of Serratia obtained from a sediment sample representative of the Sellafield nuclear site, UK. When supplied with glycerol phosphate, this Serratia strain was able to precipitate 1 mM of soluble U(VI) as uranyl phosphate minerals from the autunite group, under anaerobic and fermentative conditions. Under phosphate-limited anaerobic conditions and with glycerol as the electron donor, non-growing Serratia cells could precipitate 0.5 mM of uranium supplied as soluble U(VI), via reduction to nano-crystalline U(IV) uraninite. Some evidence for the reduction of solid phase uranyl(VI) phosphate was also observed. This study highlights the potential for Serratia and related species to play a role in the bioremediation of uranium contamination, via a range of different metabolic pathways, dependent on culturing or in situ conditions.

Uranium Biominerals Precipitated by an Environmental Isolate of Serratia under Anaerobic Conditions

PubMed Central

Newsome, Laura; Morris, Katherine; Lloyd, Jonathan. R.

2015-01-01

Stimulating the microbially-mediated precipitation of uranium biominerals may be used to treat groundwater contamination at nuclear sites. The majority of studies to date have focussed on the reductive precipitation of uranium as U(IV) by U(VI)- and Fe(III)-reducing bacteria such as Geobacter and Shewanella species, although other mechanisms of uranium removal from solution can occur, including the precipitation of uranyl phosphates via bacterial phosphatase activity. Here we present the results of uranium biomineralisation experiments using an isolate of Serratia obtained from a sediment sample representative of the Sellafield nuclear site, UK. When supplied with glycerol phosphate, this Serratia strain was able to precipitate 1 mM of soluble U(VI) as uranyl phosphate minerals from the autunite group, under anaerobic and fermentative conditions. Under phosphate-limited anaerobic conditions and with glycerol as the electron donor, non-growing Serratia cells could precipitate 0.5 mM of uranium supplied as soluble U(VI), via reduction to nano-crystalline U(IV) uraninite. Some evidence for the reduction of solid phase uranyl(VI) phosphate was also observed. This study highlights the potential for Serratia and related species to play a role in the bioremediation of uranium contamination, via a range of different metabolic pathways, dependent on culturing or in situ conditions. PMID:26132209

Bioreduction and immobilization of uranium in situ: a case study at a USA Department of Energy radioactive waste site, Oak Ridge, Tennessee

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

Wu, Weimin; Carley, Jack M; Watson, David B

Bioremediation of uranium contaminated groundwater was tested by delivery of ethanol as an electron donor source to stimulate indigenous microbial bioactivity for reduction and immobilization of uranium in situ, followed by tests of stability of uranium sequestration in the bioreduced area via delivery of dissolved oxygen or nitrate at the US Department of energy's Integrated Field Research Challenge site located at Oak Ridge, Tennessee, USA. After long term treatment that spanned years, uranium in groundwater was reduced from 40-60 mg {center_dot} L{sup -1} to <0.03 mg {center_dot} L{sup -1}, below the USA EPA standard for drinking water. The bioreduced uraniummore » was stable under anaerobic or anoxic conditions, but addition of DO and nitrate to the bioreduced zone caused U remobilization. The change in the microbial community and functional microorganisms related to uranium reduction and oxidation were characterized. The delivery of ethanol as electron donor stimulated the activities of indigenous microorganisms for reduction of U(VI) to U(IV). Results indicated that the immobilized U could be partially remobilized by D0 and nitrate via microbial activity. An anoxic environmental condition without nitrate is essential to maintain the stability of bioreduced uranium.« less

Potential impact of soil microbial heterogeneity on the persistence of hydrocarbons in contaminated subsurface soils.

PubMed

Aleer, Sam; Adetutu, Eric M; Weber, John; Ball, Andrew S; Juhasz, Albert L

2014-04-01

In situ bioremediation is potentially a cost effective treatment strategy for subsurface soils contaminated with petroleum hydrocarbons, however, limited information is available regarding the impact of soil spatial heterogeneity on bioremediation efficacy. In this study, we assessed issues associated with hydrocarbon biodegradation and soil spatial heterogeneity (samples designated as FTF 1, 5 and 8) from a site in which in situ bioremediation was proposed for hydrocarbon removal. Test pit activities showed similarities in FTF soil profiles with elevated hydrocarbon concentrations detected in all soils at 2 m below ground surface. However, PCR-DGGE-based cluster analysis showed that the bacterial community in FTF 5 (at 2 m) was substantially different (53% dissimilar) and 2-3 fold more diverse than communities in FTF 1 and 8 (with 80% similarity). When hydrocarbon degrading potential was assessed, differences were observed in the extent of (14)C-benzene mineralisation under aerobic conditions with FTF 5 exhibiting the highest hydrocarbon removal potential compared to FTF 1 and 8. Further analysis indicated that the FTF 5 microbial community was substantially different from other FTF samples and dominated by putative hydrocarbon degraders belonging to Pseudomonads, Xanthomonads and Enterobacteria. However, hydrocarbon removal in FTF 5 under anaerobic conditions with nitrate and sulphate electron acceptors was limited suggesting that aerobic conditions were crucial for hydrocarbon removal. This study highlights the importance of assessing available microbial capacity prior to bioremediation and shows that the site's spatial heterogeneity can adversely affect the success of in situ bioremediation unless area-specific optimizations are performed. Copyright © 2014 Elsevier Ltd. All rights reserved.

Genome-scale dynamic modeling of the competition between Rhodoferax and Geobacter in anoxic subsurface environments

PubMed Central

Zhuang, Kai; Izallalen, Mounir; Mouser, Paula; Richter, Hanno; Risso, Carla; Mahadevan, Radhakrishnan; Lovley, Derek R

2011-01-01

The advent of rapid complete genome sequencing, and the potential to capture this information in genome-scale metabolic models, provide the possibility of comprehensively modeling microbial community interactions. For example, Rhodoferax and Geobacter species are acetate-oxidizing Fe(III)-reducers that compete in anoxic subsurface environments and this competition may have an influence on the in situ bioremediation of uranium-contaminated groundwater. Therefore, genome-scale models of Geobacter sulfurreducens and Rhodoferax ferrireducens were used to evaluate how Geobacter and Rhodoferax species might compete under diverse conditions found in a uranium-contaminated aquifer in Rifle, CO. The model predicted that at the low rates of acetate flux expected under natural conditions at the site, Rhodoferax will outcompete Geobacter as long as sufficient ammonium is available. The model also predicted that when high concentrations of acetate are added during in situ bioremediation, Geobacter species would predominate, consistent with field-scale observations. This can be attributed to the higher expected growth yields of Rhodoferax and the ability of Geobacter to fix nitrogen. The modeling predicted relative proportions of Geobacter and Rhodoferax in geochemically distinct zones of the Rifle site that were comparable to those that were previously documented with molecular techniques. The model also predicted that under nitrogen fixation, higher carbon and electron fluxes would be diverted toward respiration rather than biomass formation in Geobacter, providing a potential explanation for enhanced in situ U(VI) reduction in low-ammonium zones. These results show that genome-scale modeling can be a useful tool for predicting microbial interactions in subsurface environments and shows promise for designing bioremediation strategies. PMID:20668487

Uranium redox transition pathways in acetate-amended sediments

USGS Publications Warehouse

Bargar, John R.; Williams, Kenneth H.; Campbell, Kate M.; Long, Philip E.; Stubbs, Joanne E.; Suvorova, Elenal I.; Lezama-Pacheco, Juan S.; Alessi, Daniel S.; Stylo, Malgorzata; Webb, Samuel M.; Davis, James A.; Giammar, Daniel E.; Blue, Lisa Y.; Bernier-Latmani, Rizlan

2013-01-01

Redox transitions of uranium [from U(VI) to U(IV)] in low-temperature sediments govern the mobility of uranium in the environment and the accumulation of uranium in ore bodies, and inform our understanding of Earth’s geochemical history. The molecular-scale mechanistic pathways of these transitions determine the U(IV) products formed, thus influencing uranium isotope fractionation, reoxidation, and transport in sediments. Studies that improve our understanding of these pathways have the potential to substantially advance process understanding across a number of earth sciences disciplines. Detailed mechanistic information regarding uranium redox transitions in field sediments is largely nonexistent, owing to the difficulty of directly observing molecular-scale processes in the subsurface and the compositional/physical complexity of subsurface systems. Here, we present results from an in situ study of uranium redox transitions occurring in aquifer sediments under sulfate-reducing conditions. Based on molecular-scale spectroscopic, pore-scale geochemical, and macroscale aqueous evidence, we propose a biotic–abiotic transition pathway in which biomass-hosted mackinawite (FeS) is an electron source to reduce U(VI) to U(IV), which subsequently reacts with biomass to produce monomeric U(IV) species. A species resembling nanoscale uraninite is also present, implying the operation of at least two redox transition pathways. The presence of multiple pathways in low-temperature sediments unifies apparently contrasting prior observations and helps to explain sustained uranium reduction under disparate biogeochemical conditions. These findings have direct implications for our understanding of uranium bioremediation, ore formation, and global geochemical processes.

Formation and Geological Sequestration of Uranium Nanoparticles in Deep Granitic Aquifer

PubMed Central

Suzuki, Yohey; Mukai, Hiroki; Ishimura, Toyoho; Yokoyama, Takaomi D.; Sakata, Shuhei; Hirata, Takafumi; Iwatsuki, Teruki; Mizuno, Takashi

2016-01-01

The stimulation of bacterial activities that convert hexavalent uranium, U(VI), to tetravalent uranium, U(IV), appears to be feasible for cost-effective remediation of contaminated aquifers. However, U(VI) reduction typically results in the precipitation of U(IV) particles less than 5 nanometers in diameter, except for environmental conditions enriched with iron. Because these tiny particles are mobile and susceptible to oxidative dissolution after the termination of nutrient injection, in situ bioremediation remains to be impractical. Here we show that U(IV) nanoparticles of coffinite (U(SiO4)1−x(OH)4x) formed in fracture-filling calcium carbonate in a granitic aquifer. In situ U-Pb isotope dating demonstrates that U(IV) nanoparticles have been sequestered in the calcium carbonate for at least 1 million years. As the microbiologically induced precipitation of calcium carbonate in aquifer systems worldwide is extremely common, we anticipate simultaneous stimulation of microbial activities for precipitation reactions of calcium carbonate and U(IV) nanoparticles, which leads to long-term sequestration of uranium and other radionuclides in contaminated aquifers and deep geological repositories. PMID:26948389

Formation and Geological Sequestration of Uranium Nanoparticles in Deep Granitic Aquifer.

PubMed

Suzuki, Yohey; Mukai, Hiroki; Ishimura, Toyoho; Yokoyama, Takaomi D; Sakata, Shuhei; Hirata, Takafumi; Iwatsuki, Teruki; Mizuno, Takashi

2016-03-07

The stimulation of bacterial activities that convert hexavalent uranium, U(VI), to tetravalent uranium, U(IV), appears to be feasible for cost-effective remediation of contaminated aquifers. However, U(VI) reduction typically results in the precipitation of U(IV) particles less than 5 nanometers in diameter, except for environmental conditions enriched with iron. Because these tiny particles are mobile and susceptible to oxidative dissolution after the termination of nutrient injection, in situ bioremediation remains to be impractical. Here we show that U(IV) nanoparticles of coffinite (U(SiO4)1-x(OH)4x) formed in fracture-filling calcium carbonate in a granitic aquifer. In situ U-Pb isotope dating demonstrates that U(IV) nanoparticles have been sequestered in the calcium carbonate for at least 1 million years. As the microbiologically induced precipitation of calcium carbonate in aquifer systems worldwide is extremely common, we anticipate simultaneous stimulation of microbial activities for precipitation reactions of calcium carbonate and U(IV) nanoparticles, which leads to long-term sequestration of uranium and other radionuclides in contaminated aquifers and deep geological repositories.

Optimization of a bioremediation system of soluble uranium based on the biostimulation of an indigenous bacterial community.

PubMed

Maleke, Maleke; Williams, Peter; Castillo, Julio; Botes, Elsabe; Ojo, Abidemi; DeFlaun, Mary; van Heerden, Esta

2015-06-01

High concentrations of uranium(VI) in the Witwatersrand Basin, South Africa from mining leachate is a serious environmental concern. Treatment systems are often ineffective. Therefore, optimization of a bioremediation system that facilitates the bioreduction of U(VI) based on biostimulation of indigenous bacterial communities can be a viable alternative. Tolerance of the indigenous bacteria to high concentrations of U and the amount of citric acid required for U removal was optimized. Two bioreactor studies which showed effective U(VI) removal more than 99 % from low (0.0037 mg L(-1)) and high (10 mg L(-1)) concentrations of U to below the limit allowed by South African National Standards for drinking water (0.0015 mg L(-1)). The second bioreactor was able to successfully adapt even with increasing levels of U(VI) feed water up to 10 mg L(-1), provided that enough electron donor was available. Molecular biology analyses identified Desulfovibrio sp. and Geobacter sp. among known species, which are known to reduce U(VI). The mineralogical analysis determined that part of the uranium precipitated intracellularly, which meant that the remaining U(VI) was precipitated as U(IV) oxides and TEM-EDS also confirmed this analysis. This was predicted with the geochemical model from the chemical data, which demonstrated that the treated drainage was supersaturated with respect to uraninite > U4O9 > U3O8 > UO2(am). Therefore, the tolerance of the indigenous bacterial community could be optimized to remediate up to 10 mg L(-1), and the system can thus be upscaled and employed for remediation of U(VI) impacted sites.

A scrutiny of heterogeneity at the TCE Source Area BioREmediation (SABRE) test site

NASA Astrophysics Data System (ADS)

Rivett, M.; Wealthall, G. P.; Mcmillan, L. A.; Zeeb, P.

2015-12-01

A scrutiny of heterogeneity at the UK's Source Area BioREmediation (SABRE) test site is presented to better understand how spatial heterogeneity in subsurface properties and process occurrence may constrain performance of enhanced in-situ bioremediation (EISB). The industrial site contained a 25 to 45 year old trichloroethene (TCE) dense non-aqueous phase liquid (DNAPL) that was exceptionally well monitored via a network of multilevel samplers and high resolution core sampling. Moreover, monitoring was conducted within a 3-sided sheet-pile cell that allowed a controlled streamtube of flow to be drawn through the source zone by an extraction well. We primarily focus on the longitudinal transect of monitoring along the length of the cell that provides a 200 groundwater point sample slice along the streamtube of flow through the DNAPL source zone. TCE dechlorination is shown to be significant throughout the cell domain, but spatially heterogeneous in occurrence and progress of dechlorination to lesser chlorinated ethenes - it is this heterogeneity in dechlorination that we primarily scrutinise. We illustrate the diagnostic use of the relative occurrence of TCE parent and daughter compounds to confirm: dechlorination in close proximity to DNAPL and enhanced during the bioremediation; persistent layers of DNAPL into which gradients of dechlorination products are evident; fast flowpaths through the source zone where dechlorination is less evident; and, the importance of underpinning flow regime understanding on EISB performance. Still, even with such spatial detail, there remains uncertainty over the dataset interpretation. These includes poor closure of mass balance along the cell length for the multilevel sampler based monitoring and points to needs to still understand lateral flows (even in the constrained cell), even greater spatial resolution of point monitoring and potentially, not easily proven, ethene degradation loss.

MURMoT. Design and Application of Microbial Uranium Reduction Monitoring Tools

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

Loeffler, Frank E.

2014-12-31

Uranium (U) contamination in the subsurface is a major remediation challenge at many DOE sites. Traditional site remedies present enormous costs to DOE; hence, enhanced bioremediation technologies (i.e., biostimulation and bioaugmentation) combined with monitoring efforts are being considered as cost-effective corrective actions to address subsurface contamination. This research effort improved understanding of the microbial U reduction process and developed new tools for monitoring microbial activities. Application of these tools will promote science-based site management decisions that achieve contaminant detoxification, plume control, and long-term stewardship in the most efficient manner. The overarching hypothesis was that the design, validation and application ofmore » a suite of new molecular and biogeochemical tools advance process understanding, and improve environmental monitoring regimes to assess and predict in situ U immobilization. Accomplishments: This project (i) advanced nucleic acid-based approaches to elucidate the presence, abundance, dynamics, spatial distribution, and activity of metal- and radionuclide-detoxifying bacteria; (ii) developed proteomics workflows for detection of metal reduction biomarker proteins in laboratory cultures and contaminated site groundwater; (iii) developed and demonstrated the utility of U isotopic fractionation using high precision mass spectrometry to quantify U(VI) reduction for a range of reduction mechanisms and environmental conditions; and (iv) validated the new tools using field samples from U-contaminated IFRC sites, and demonstrated their prognostic and diagnostic capabilities in guiding decision making for environmental remediation and long-term site stewardship.« less

Uranium reduction and resistance to reoxidation under iron-reducing and sulfate-reducing conditions.

PubMed

Boonchayaanant, Benjaporn; Nayak, Dipti; Du, Xin; Criddle, Craig S

2009-10-01

Oxidation and mobilization of microbially-generated U(IV) is of great concern for in situ uranium bioremediation. This study investigated the reoxidation of uranium by oxygen and nitrate in a sulfate-reducing enrichment and an iron-reducing enrichment derived from sediment and groundwater from the Field Research Center in Oak Ridge, Tennessee. Both enrichments were capable of reducing U(VI) rapidly. 16S rRNA gene clone libraries of the two enrichments revealed that Desulfovibrio spp. are dominant in the sulfate-reducing enrichment, and Clostridium spp. are dominant in the iron-reducing enrichment. In both the sulfate-reducing enrichment and the iron-reducing enrichment, oxygen reoxidized the previously reduced uranium but to a lesser extent in the iron-reducing enrichment. Moreover, in the iron-reducing enrichment, the reoxidized U(VI) was eventually re-reduced to its previous level. In both, the sulfate-reducing enrichment and the iron-reducing enrichment, uranium reoxidation did not occur in the presence of nitrate. The results indicate that the Clostridium-dominated iron-reducing communities created conditions that were more favorable for uranium stability with respect to reoxidation despite the fact that fewer electron equivalents were added to these systems. The likely reason is that more of the added electrons are present in a form that can reduce oxygen to water and U(VI) back to U(IV).

Microbial biogeochemistry of uranium mill tailings

USGS Publications Warehouse

Landa, Edward R.

2005-01-01

Uranium mill tailings (UMT) are the crushed ore residues from the extraction of uranium (U) from ores. Among the radioactive wastes associated with the nuclear fuel cycle, UMT are unique in terms of their volume and their limited isolation from the surficial environment. For this latter reason, their management and long-term fate has many interfaces with environmental microbial communities and processes. The interactions of microorganisms with UMT have been shown to be diverse and with significant consequences for radionuclide mobility and bioremediation. These radionuclides are associated with the U-decay series. The addition of organic carbon and phosphate is required to initiate the reduction of the U present in the groundwater down gradient of the mills. Investigations on sediment and water from the U-contaminated aquifer, indicates that the addition of a carbon source stimulates the rate of U removal by microbial reduction. Moreover, most attention with respect to passive or engineered removal of U from groundwaters focuses on iron-reducing and sulfate-reducing bacteria.

Réduction des nitrates et de l'uranium par les bactéries indigènes

NASA Astrophysics Data System (ADS)

Abdelouas, Abdesselam; Lutze, Werner; Nuttall, Eric

1998-07-01

A bioremediation concept has been developed to clean up ground water contaminated with nitrate (1200 mg·L -1) and uranium (0.25 mg·L -1). We studied the Tuba City mill tailings site, Arizona, USA. Indigenous bacteria capable of catalyzing the reduction of NO 3- and U(VI) were identified in the ground water and in the host rock, the Navajo sandstone. After complete reduction of O 2 and NO 3- within one week, U(VI) was reduced and precipitated as uraninite. Final uranium concentrations < 15 μg·L -1 were reached after a few weeks at 24 °C. Iron sulfide also precipitated as a result of reduction of Fe(III) on the sand surface and sulfate in the ground water. U(VI) was not reduced by sulfide. It was found that enzymatic reduction of U(VI) is faster than abiotic reduction under the conditions given by the composition of the ground water.

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

Joel E. Kostka

This project represented a joint effort between Oak Ridge National Laboratory (ORNL), the University of Tennessee (UT), and Florida State University (FSU). ORNL served as the lead in-stitution with Dr. A.V. Palumbo responsible for project coordination, integration, and deliver-ables. In situ uranium bioremediation is focused on biostimulating indigenous microorganisms through a combination of pH neutralization and the addition of large amounts of electron donor. Successful biostimulation of U(VI) reduction has been demonstrated in the field and in the laboratory. However, little data is available on the dynamics of microbial populations capable of U(VI) reduction, and the differences in the microbialmore » community dynamics between proposed electron donors have not been explored. In order to elucidate the potential mechanisms of U(VI) reduction for optimization of bioremediation strategies, structure-function relationships of microbial populations were investigated in microcosms of subsurface materials cocontaminated with radionuclides and nitrate from the Oak Ridge Field Research Center (ORFRC), Oak Ridge, Tennessee.« less

Network succession reveals the importance of competition in response to emulsified vegetable oil amendment for uranium bioremediation.

PubMed

Deng, Ye; Zhang, Ping; Qin, Yujia; Tu, Qichao; Yang, Yunfeng; He, Zhili; Schadt, Christopher Warren; Zhou, Jizhong

2016-01-01

Discerning network interactions among different species/populations in microbial communities has evoked substantial interests in recent years, but little information is available about temporal dynamics of microbial network interactions in response to environmental perturbations. Here, we modified the random matrix theory-based network approach to discern network succession in groundwater microbial communities in response to emulsified vegetable oil (EVO) amendment for uranium bioremediation. Groundwater microbial communities from one control and seven monitor wells were analysed with a functional gene array (GeoChip 3.0), and functional molecular ecological networks (fMENs) at different time points were reconstructed. Our results showed that the network interactions were dramatically altered by EVO amendment. Dynamic and resilient succession was evident: fairly simple at the initial stage (Day 0), increasingly complex at the middle period (Days 4, 17, 31), most complex at Day 80, and then decreasingly complex at a later stage (140-269 days). Unlike previous studies in other habitats, negative interactions predominated in a time-series fMEN, suggesting strong competition among different microbial species in the groundwater systems after EVO injection. Particularly, several keystone sulfate-reducing bacteria showed strong negative interactions with their network neighbours. These results provide mechanistic understanding of the decreased phylogenetic diversity during environmental perturbations. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

Long-term in situ oxidation of biogenic uraninite in an alluvial aquifer: impact of dissolved oxygen and calcium.

PubMed

Lezama-Pacheco, Juan S; Cerrato, José M; Veeramani, Harish; Alessi, Daniel S; Suvorova, Elena; Bernier-Latmani, Rizlan; Giammar, Daniel E; Long, Philip E; Williams, Kenneth H; Bargar, John R

2015-06-16

Oxidative dissolution controls uranium release to (sub)oxic pore waters from biogenic uraninite produced by natural or engineered processes, such as bioremediation. Laboratory studies show that uraninite dissolution is profoundly influenced by dissolved oxygen (DO), carbonate, and solutes such as Ca(2+). In complex and heterogeneous subsurface environments, the concentrations of these solutes vary in time and space. Knowledge of dissolution processes and kinetics occurring over the long-term under such conditions is needed to predict subsurface uranium behavior and optimize the selection and performance of uraninite-based remediation technologies over multiyear periods. We have assessed dissolution of biogenic uraninite deployed in wells at the Rifle, CO, DOE research site over a 22 month period. Uraninite loss rates were highly sensitive to DO, with near-complete loss at >0.6 mg/L over this period but no measurable loss at lower DO. We conclude that uraninite can be stable over decadal time scales in aquifers under low DO conditions. U(VI) solid products were absent over a wide range of DO values, suggesting that dissolution proceeded through complexation and removal of oxidized surface uranium atoms by carbonate. Moreover, under the groundwater conditions present, Ca(2+) binds strongly to uraninite surfaces at structural uranium sites, impacting uranium fate.

Reduction of uranium by cytochrome c3 of Desulfovibrio vulgaris

USGS Publications Warehouse

Lovley, D.R.; Widman, P.K.; Woodward, J.C.; Phillips, E.J.P.

1993-01-01

The mechanism for U(VI) reduction by Desulfovibrio vulgaris (Hildenborough) was investigated. The H2-dependent U(VI) reductase activity in the soluble fraction of the cells was lost when the soluble fraction was passed over a cationic exchange column which extracted cytochrome c3. Addition of cytochrome c3 back to the soluble fraction that had been passed over the cationic exchange column restored the U(VI)-reducing capacity. Reduced cytochrome c3 was oxidized by U(VI), as was a c-type cytochrome(s) in whole-cell suspensions. When cytochrome c3 was combined with hydrogenase, its physiological electron donor, U(VI) was reduced in the presence of H2. Hydrogenase alone could not reduce U(VI). Rapid U(VI) reduction was followed by a subsequent slow precipitation of the U(IV) mineral uraninite. Cytochrome c3 reduced U(VI) in a uranium-contaminated surface water and groundwater. Cytochrome c3 provides the first enzyme model for the reduction and biomineralization of uranium in sedimentary environments. Furthermore, the finding that cytochrome c3 can catalyze the reductive precipitation of uranium may aid in the development of fixed-enzyme reactors and/or organisms with enhanced U(VI)-reducing capacity for the bioremediation of uranium- contaminated waters and waste streams.

Bioremediation of Metals and Radionuclides: What It Is and How It Works (2nd Edition)

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

Palmisano, Anna; Hazen, Terry

2003-09-30

This primer is intended for people interested in environmental problems of the U.S. Department of Energy (DOE) and in their potential solutions. It will specifically look at some of the more hazardous metal and radionuclide contaminants found on DOE lands and at the possibilities for using bioremediation technology to clean up these contaminants. The second edition of the primer incorporates recent findings by researchers in DOE's Natural and Accelerated Bioremediation Research (NABIR) Program. Bioremediation is a technology that can be used to reduce, eliminate, or contain hazardous waste. Over the past two decades, it has become widely accepted that microorganisms,more » and to a lesser extent plants, can transform and degrade many types of contaminants. These transformation and degradation processes vary, depending on the physical-chemical environment, microbial communities, and nature of the contaminant. This technology includes intrinsic bioremediation, which relies on naturally occurring processes, and accelerated bioremediation, which enhances microbial degradation or transformation through the addition of nutrients (biostimulation) or inoculation with microorganisms (bioaugmentation). Over the past few years, interest in bioremediation has increased. It has become clear that many organic contaminants such as hydrocarbon fuels can be degraded to relatively harmless products such as CO{sub 2} (the end result of the degradation process). Waste water managers and scientists have also found that microorganisms can interact with metals and convert them from one chemical form to another. Laboratory tests and ex situ bioremediation applications have shown that microorganisms can change the valence, or oxidation state, of some heavy metals (e.g., chromium and mercury) and radionuclides (e.g., uranium) by using them as electron acceptors. In some cases, the solubility of the altered species decreases and the contaminant is immobilized in situ, i.e., precipitated into an insoluble salt in the sediment. In other cases, the opposite occurs--the solubility of the altered species increases, increasing the mobility of the contaminant and allowing it to be more easily flushed from the environment. Both of these kinds of transformations present opportunities for bioremediation of metals and radionuclides--either to lock them in place, or to accelerate their removal. DOE's goal is to reduce the risk and related exposure to ground water, sediment, and soil contamination at Department of Energy facilities. Subsurface bioremediation of metals and radionuclides at the site of contamination (in situ bioremediation) is not yet in widespread use. However, successful in situ applications of bioremediation to petroleum products and chlorinated solvents provide experience from which scientists can draw. Taken together, the accomplishments in these areas have led scientists and engineers to be optimistic about applying this technology to the mixtures of metals and radionuclides that are found at some of the most contaminated DOE sites. This primer examines some of the basic microbial and chemical processes that are a part of bioremediation, specifically the bioremediation of metals and radionuclides. The primer is divided into six sections, with the information in each building on that of the previous. The sections include features that highlight topics of interest and provide background information on specific biological and chemical processes and reactions. The first section briefly examines the scope of the contamination problem at DOE facilities. The second section gives a summary of some of the most commonly used bioremediation technologies, including successful in situ and ex situ techniques. The third discusses chemical and physical properties of metals and radionuclides found in contaminant mixtures at DOE sites, including solubility and the most common oxidation states in which these materials are found. The fourth section is an overview of the basic microbial processes that occur in bioremediation. The fifth section looks at specific in situ bioremediation processes that can be used on these contaminant mixtures. The primer concludes with examples of field research on bioremediation of metals and radionuclides.« less

Uranium isotopes fingerprint biotic reduction.

PubMed

Stylo, Malgorzata; Neubert, Nadja; Wang, Yuheng; Monga, Nikhil; Romaniello, Stephen J; Weyer, Stefan; Bernier-Latmani, Rizlan

2015-05-05

Knowledge of paleo-redox conditions in the Earth's history provides a window into events that shaped the evolution of life on our planet. The role of microbial activity in paleo-redox processes remains unexplored due to the inability to discriminate biotic from abiotic redox transformations in the rock record. The ability to deconvolute these two processes would provide a means to identify environmental niches in which microbial activity was prevalent at a specific time in paleo-history and to correlate specific biogeochemical events with the corresponding microbial metabolism. Here, we demonstrate that the isotopic signature associated with microbial reduction of hexavalent uranium (U), i.e., the accumulation of the heavy isotope in the U(IV) phase, is readily distinguishable from that generated by abiotic uranium reduction in laboratory experiments. Thus, isotope signatures preserved in the geologic record through the reductive precipitation of uranium may provide the sought-after tool to probe for biotic processes. Because uranium is a common element in the Earth's crust and a wide variety of metabolic groups of microorganisms catalyze the biological reduction of U(VI), this tool is applicable to a multiplicity of geological epochs and terrestrial environments. The findings of this study indicate that biological activity contributed to the formation of many authigenic U deposits, including sandstone U deposits of various ages, as well as modern, Cretaceous, and Archean black shales. Additionally, engineered bioremediation activities also exhibit a biotic signature, suggesting that, although multiple pathways may be involved in the reduction, direct enzymatic reduction contributes substantially to the immobilization of uranium.

Uranium isotopes fingerprint biotic reduction

DOE PAGES

Stylo, Malgorzata; Neubert, Nadja; Wang, Yuheng; ...

2015-04-20

Knowledge of paleo-redox conditions in the Earth’s history provides a window into events that shaped the evolution of life on our planet. The role of microbial activity in paleo-redox processes remains unexplored due to the inability to discriminate biotic from abiotic redox transformations in the rock record. The ability to deconvolute these two processes would provide a means to identify environmental niches in which microbial activity was prevalent at a specific time in paleo-history and to correlate specific biogeochemical events with the corresponding microbial metabolism. Here, we demonstrate that the isotopic signature associated with microbial reduction of hexavalent uranium (U),more » i.e., the accumulation of the heavy isotope in the U(IV) phase, is readily distinguishable from that generated by abiotic uranium reduction in laboratory experiments. Thus, isotope signatures preserved in the geologic record through the reductive precipitation of uranium may provide the sought-after tool to probe for biotic processes. Because uranium is a common element in the Earth’s crust and a wide variety of metabolic groups of microorganisms catalyze the biological reduction of U(VI), this tool is applicable to a multiplicity of geological epochs and terrestrial environments. The findings of this study indicate that biological activity contributed to the formation of many authigenic U deposits, including sandstone U deposits of various ages, as well as modern, Cretaceous, and Archean black shales. In addition, engineered bioremediation activities also exhibit a biotic signature, suggesting that, although multiple pathways may be involved in the reduction, direct enzymatic reduction contributes substantially to the immobilization of uranium.« less

Composition, stability, and measurement of reduced uranium phases for groundwater bioremediation at Old Rifle, CO

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

Campbell, K. M.; Davis, J. A.; Bargar, J.

2011-10-15

Reductive biostimulation is currently being explored as a possible remediation strategy for uranium (U) contaminated groundwater, and is currently being investigated at a field site in Rifle, CO, USA. The long-term stability of the resulting U(IV) phases is a key component of the overall performance and depends upon a variety of factors, including rate and mechanism of reduction, mineral associations in the subsurface, and propensity for oxidation. To address these factors, several approaches were used to evaluate the redox sensitivity of U: measurement of the rate of oxidative dissolution of biogenic uraninite (UO{sub 2(s)}) deployed in groundwater at Rifle, characterizationmore » of a zone of natural bioreduction exhibiting relevant reduced mineral phases, and laboratory studies of the oxidative capacity of Fe(III) and reductive capacity of Fe(II) with regard to U(IV) and U(VI), respectively.« less

Assessing TCE source bioremediation by geostatistical analysis of a flux fence.

PubMed

Cai, Zuansi; Wilson, Ryan D; Lerner, David N

2012-01-01

Mass discharge across transect planes is increasingly used as a metric for performance assessment of in situ groundwater remediation systems. Mass discharge estimates using concentrations measured in multilevel transects are often made by assuming a uniform flow field, and uncertainty contributions from spatial concentration and flow field variability are often overlooked. We extend our recently developed geostatistical approach to estimate mass discharge using transect data of concentration and hydraulic conductivity, so accounting for the spatial variability of both datasets. The magnitude and uncertainty of mass discharge were quantified by conditional simulation. An important benefit of the approach is that uncertainty is quantified as an integral part of the mass discharge estimate. We use this approach for performance assessment of a bioremediation experiment of a trichloroethene (TCE) source zone. Analyses of dissolved parent and daughter compounds demonstrated that the engineered bioremediation has elevated the degradation rate of TCE, resulting in a two-thirds reduction in the TCE mass discharge from the source zone. The biologically enhanced dissolution of TCE was not significant (~5%), and was less than expected. However, the discharges of the daughter products cis-1,2, dichloroethene (cDCE) and vinyl chloride (VC) increased, probably because of the rapid transformation of TCE from the source zone to the measurement transect. This suggests that enhancing the biodegradation of cDCE and VC will be crucial to successful engineered bioremediation of TCE source zones. © 2012, The Author(s). Ground Water © 2012, National Ground Water Association.

Bioremediation of Uranium-Contaminated Groundwater using Engineered Injection and Extraction

NASA Astrophysics Data System (ADS)

Greene, J. A.; Neupauer, R.; Ye, M.; Kasprzyk, J. R.; Mays, D. C.; Curtis, G. P.

2017-12-01

During in-situ remediation of contaminated groundwater, a treatment chemical is injected into the contaminated groundwater to react with and degrade the contaminant, with reactions occurring where the treatment chemical contacts the contaminant. Traditional in-situ groundwater remediation relies on background groundwater flow for spreading of treatment chemicals into contaminant plumes. Engineered Injection and Extraction (EIE), in which time-varying induced flow fields are used to actively spread the treatment chemical into the contaminant plume, has been developed to increase contact between the contaminant and treatment chemical, thereby enhancing contaminant degradation. EIE has been investigated for contaminants that degrade through irreversible bimolecular reaction with a treatment chemical, but has not been investigated for a contaminant governed by reversible reactions. Uranium primarily occurs in its aqueous, mobile form, U(VI), in the environment but can be bioreduced to its sparingly soluble, immobile form, U(IV), by iron reducing bacteria stimulated by an acetate amendment. In this study, we investigate the ability of EIE to facilitate and sustain favorable conditions to immobilize uranium during remediation, and to prevent re-mobilization of uranium into the aqueous phase after active remediation has ended. Simulations in this investigation are conducted using a semi-synthetic model based on physical and chemical conditions at the Naturita Uranium Mill Tailings Remedial Action (UMTRA) site in southwestern Colorado and the Old Rifle UMTRA site in western Colorado. The EIE design is optimized for the synthetic model using the Borg multi-objective evolutionary algorithm.

In situ bioremediation of uranium with emulsified vegetable oil as the electron donor.

PubMed

Watson, David B; Wu, Wei-Min; Mehlhorn, Tonia; Tang, Guoping; Earles, Jennifer; Lowe, Kenneth; Gihring, Thomas M; Zhang, Gengxin; Phillips, Jana; Boyanov, Maxim I; Spalding, Brian P; Schadt, Christopher; Kemner, Kenneth M; Criddle, Craig S; Jardine, Philip M; Brooks, Scott C

2013-06-18

A field test with a one-time emulsified vegetable oil (EVO) injection was conducted to assess the capacity of EVO to sustain uranium bioreduction in a high-permeability gravel layer with groundwater concentrations of (mM) U, 0.0055; Ca, 2.98; NO3(-), 0.11; HCO3(-), 5.07; and SO4(2-), 1.23. Comparison of bromide and EVO migration and distribution indicated that a majority of the injected EVO was retained in the subsurface from the injection wells to 50 m downgradient. Nitrate, uranium, and sulfate were sequentially removed from the groundwater within 1-2 weeks, accompanied by an increase in acetate, Mn, Fe, and methane concentrations. Due to the slow release and degradation of EVO with time, reducing conditions were sustained for approximately one year, and daily U discharge to a creek, located approximately 50 m from the injection wells, decreased by 80% within 100 days. Total U discharge was reduced by 50% over the one-year period. Reduction of U(VI) to U(IV) was confirmed by synchrotron analysis of recovered aquifer solids. Oxidants (e.g., dissolved oxygen, nitrate) flowing in from upgradient appeared to reoxidize and remobilize uranium after the EVO was exhausted as evidenced by a transient increase of U concentration above ambient values. Occasional (e.g., annual) EVO injection into a permeable Ca and bicarbonate-containing aquifer can sustain uranium bioreduction/immobilization and decrease U migration/discharge.

Molecular Analysis of the In Situ Growth Rates of Subsurface Geobacter Species

PubMed Central

Giloteaux, Ludovic; Barlett, Melissa; Chavan, Milind A.; Smith, Jessica A.; Williams, Kenneth H.; Wilkins, Michael; Long, Philip; Lovley, Derek R.

2013-01-01

Molecular tools that can provide an estimate of the in situ growth rate of Geobacter species could improve understanding of dissimilatory metal reduction in a diversity of environments. Whole-genome microarray analyses of a subsurface isolate of Geobacter uraniireducens, grown under a variety of conditions, identified a number of genes that are differentially expressed at different specific growth rates. Expression of two genes encoding ribosomal proteins, rpsC and rplL, was further evaluated with quantitative reverse transcription-PCR (qRT-PCR) in cells with doubling times ranging from 6.56 h to 89.28 h. Transcript abundance of rpsC correlated best (r2 = 0.90) with specific growth rates. Therefore, expression patterns of rpsC were used to estimate specific growth rates of Geobacter species during an in situ uranium bioremediation field experiment in which acetate was added to the groundwater to promote dissimilatory metal reduction. Initially, increased availability of acetate in the groundwater resulted in higher expression of Geobacter rpsC, and the increase in the number of Geobacter cells estimated with fluorescent in situ hybridization compared well with specific growth rates estimated from levels of in situ rpsC expression. However, in later phases, cell number increases were substantially lower than predicted from rpsC transcript abundance. This change coincided with a bloom of protozoa and increased attachment of Geobacter species to solid phases. These results suggest that monitoring rpsC expression may better reflect the actual rate that Geobacter species are metabolizing and growing during in situ uranium bioremediation than changes in cell abundance. PMID:23275510

Direct coupling of a genome-scale microbial in silico model and a groundwater reactive transport model.

PubMed

Fang, Yilin; Scheibe, Timothy D; Mahadevan, Radhakrishnan; Garg, Srinath; Long, Philip E; Lovley, Derek R

2011-03-25

The activity of microorganisms often plays an important role in dynamic natural attenuation or engineered bioremediation of subsurface contaminants, such as chlorinated solvents, metals, and radionuclides. To evaluate and/or design bioremediated systems, quantitative reactive transport models are needed. State-of-the-art reactive transport models often ignore the microbial effects or simulate the microbial effects with static growth yield and constant reaction rate parameters over simulated conditions, while in reality microorganisms can dynamically modify their functionality (such as utilization of alternative respiratory pathways) in response to spatial and temporal variations in environmental conditions. Constraint-based genome-scale microbial in silico models, using genomic data and multiple-pathway reaction networks, have been shown to be able to simulate transient metabolism of some well studied microorganisms and identify growth rate, substrate uptake rates, and byproduct rates under different growth conditions. These rates can be identified and used to replace specific microbially-mediated reaction rates in a reactive transport model using local geochemical conditions as constraints. We previously demonstrated the potential utility of integrating a constraint-based microbial metabolism model with a reactive transport simulator as applied to bioremediation of uranium in groundwater. However, that work relied on an indirect coupling approach that was effective for initial demonstration but may not be extensible to more complex problems that are of significant interest (e.g., communities of microbial species and multiple constraining variables). Here, we extend that work by presenting and demonstrating a method of directly integrating a reactive transport model (FORTRAN code) with constraint-based in silico models solved with IBM ILOG CPLEX linear optimizer base system (C library). The models were integrated with BABEL, a language interoperability tool. The modeling system is designed in such a way that constraint-based models targeting different microorganisms or competing organism communities can be easily plugged into the system. Constraint-based modeling is very costly given the size of a genome-scale reaction network. To save computation time, a binary tree is traversed to examine the concentration and solution pool generated during the simulation in order to decide whether the constraint-based model should be called. We also show preliminary results from the integrated model including a comparison of the direct and indirect coupling approaches and evaluated the ability of the approach to simulate field experiment. Published by Elsevier B.V.

Uranium mineralization and unconformities: how do they correlate? - A look beyond the classic unconformity-type deposit model?

NASA Astrophysics Data System (ADS)

Markwitz, Vanessa; Porwal, Alok; Campbell McCuaig, T.; Kreuzer, Oliver P.

2010-05-01

Uranium deposits are usually classified based on the characteristics of their host rocks and geological environments (Dahlkamp, 1993; OECD/NEA Red Book and IAEA, 2000; Cuney, 2009). The traditional unconformity-related deposit types are the most economical deposits in the world, with the highest grades amongst all uranium deposit types. In order to predict undiscovered uranium deposits, there is a need to understand the spatial association of uranium mineralization with structures and unconformities. Hydrothermal uranium deposits develop by uranium enriched fluids from source rocks, transported along permeable pathways to their depositional environment. Unconformities are not only separating competent from incompetent sequences, but provide the physico-chemical gradient in the depositional environment. They acted as important fluid flow pathways for uranium to migrate not only for surface-derived oxygenated fluids, but also for high oxidized metamorphic and magmatic fluids, dominated by their geological environment in which the unconformities occur. We have carried out comprehensive empirical spatial analyses of various types of uranium deposits in Australia, and first results indicate that there is a strong spatial correlation between unconformities and uranium deposits, not only for traditional unconformity-related deposits but also for other styles. As a start we analysed uranium deposits in Queensland and in particular Proterozoic metasomatic-related deposits in the Mount Isa Inlier and Late Carboniferous to Early Permian volcanic-hosted uranium occurrences in Georgetown and Charters Towers Regions show strong spatial associations with contemporary and older unconformities. The Georgetown Inlier in northern Queensland consists of a diverse range of rocks, including Proterozoic and early Palaeozoic metamorphic rocks and granites and late Palaeozoic volcanic rocks and related granites. Uranium-molybdenum (+/- fluorine) mineralization in the Georgetown inlier varies from strata- to structure-bound and occurs above regional unconformities. The Proterozoic basins in the Mount Isa Inlier rest unconformably on Palaeoproterozoic basement accompanied by volcanic and igneous rocks, which were deformed and metamorphosed in the Mesoproterozoic. Uranium occurrences in the Western Succession of Mount Isa are either hosted in clastic metasediments or mafic volcanics that belong to the Palaeoproterozoic Eastern Creek Volcanics. Uranium and vanadium mineralization occur in metasomatised and hematite-magnetite-carbonate alteration zones, bounded by major faults and regional unconformities. The results of this study highlight the importance of unconformities in uranium minerals systems as possible fluid pathways and/or surfaces of physico-chemical contrast that could have facilitated the precipitation of uranium, not only in classical unconformity style uranium deposits but in several other styles of uranium mineralization as well. References Cuney, M., 2009. The extreme diversity of uranium deposits. Mineralium Deposita, 44, 3-9. Dahlkamp, F. J., 1993. Uranium ore deposits. Springer, Berlin, p 460. OECD / NEA Red Book & IAEA, 2000. Uranium 1999: Resources, Production and Demand. OECD Nuclear Energy Agency and International Atomic Energy Agency, Paris.

Microbial Community Changes in Response to Ethanol or Methanol Amendments for U(VI) Reduction

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

Vishnivetskaya, Tatiana A; Brandt, Craig C; Madden, Andrew

2010-01-01

Microbial community responses to ethanol, methanol and methanol + humics amendments in relationship to uranium bioremediation were studied in laboratory microcosm experiments using sediments and ground water from a uranium-contaminated site in Oak Ridge, Tennessee. Ethanol addition always resulted in uranium reduction at rate of 0.8-1.0 mol l-1 d-1 while methanol addition did so occasionally at rate 0.95 mol l-1 d-1. The type of carbon source added, the duration of incubation, and the sampling site influenced the bacterial community structure upon incubation. Analysis of 16S rRNA gene clone libraries indicated (1) bacterial communities found in ethanol- and methanol-amended samples withmore » U(VI) reduction were similar due to presence of -Proteobacteria, and -Proteobacteria (members of the families Burkholderiaceae, Comamonadaceae, Oxalobacteraceae, and Rhodocyclaceae); (2) methanol-amended samples without U(VI) reduction exhibited the lowest diversity and the bacterial community contained 69.2-92.8% of the family Methylophilaceae; and (3) the addition of humics resulted in an increase of phylogenetic diversity of -Proteobacteria (Rodoferax, Polaromonas, Janthinobacterium, Methylophilales, unclassified) and Firmicutes (Desulfosporosinus, Clostridium).« less

Oxidative dissolution of biogenic uraninite in groundwater at Old Rifle, CO

USGS Publications Warehouse

Campbell, Kate M.; Veeramani, Harish; Ulrich, Kai-Uwe; Blue, Lisa Y.; Giammar, Dianiel E.; Bernier-Latmani, Rizlan; Stubbs, Joanne E.; Suvorova, Elena; Yabusaki, Steve; Lezama-Pacheco, Juan S.; Mehta, Apurva; Long, Philip E.; Bargar, John R.

2011-01-01

Reductive bioremediation is currently being explored as a possible strategy for uranium-contaminated aquifers such as the Old Rifle site (Colorado). The stability of U(IV) phases under oxidizing conditions is key to the performance of this procedure. An in situ method was developed to study oxidative dissolution of biogenic uraninite (UO2), a desirable U(VI) bioreduction product, in the Old Rifle, CO, aquifer under different variable oxygen conditions. Overall uranium loss rates were 50–100 times slower than laboratory rates. After accounting for molecular diffusion through the sample holders, a reactive transport model using laboratory dissolution rates was able to predict overall uranium loss. The presence of biomass further retarded diffusion and oxidation rates. These results confirm the importance of diffusion in controlling in-aquifer U(IV) oxidation rates. Upon retrieval, uraninite was found to be free of U(VI), indicating dissolution occurred via oxidation and removal of surface atoms. Interaction of groundwater solutes such as Ca2+ or silicate with uraninite surfaces also may retard in-aquifer U loss rates. These results indicate that the prolonged stability of U(IV) species in aquifers is strongly influenced by permeability, the presence of bacterial cells and cell exudates, and groundwater geochemistry.

Uranium Biomineralization By Natural Microbial Phosphatase Activities in the Subsurface

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

Taillefert, Martial

This project investigated the geochemical and microbial processes associated with the biomineralization of radionuclides in subsurface soils. During this study, it was determined that microbial communities from the Oak Ridge Field Research subsurface are able to express phosphatase activities that hydrolyze exogenous organophosphate compounds and result in the non-reductive bioimmobilization of U(VI) phosphate minerals in both aerobic and anaerobic conditions. The changes of the microbial community structure associated with the biomineralization of U(VI) was determined to identify the main organisms involved in the biomineralization process, and the complete genome of two isolates was sequenced. In addition, it was determined thatmore » both phytate, the main source of natural organophosphate compounds in natural environments, and polyphosphate accumulated in cells could also be hydrolyzed by native microbial population to liberate enough orthophosphate and precipitate uranium phosphate minerals. Finally, the minerals produced during this process are stable in low pH conditions or environments where the production of dissolved inorganic carbon is moderate. These findings suggest that the biomineralization of U(VI) phosphate minerals is an attractive bioremediation strategy to uranium bioreduction in low pH uranium-contaminated environments. These efforts support the goals of the SBR long-term performance measure by providing key information on "biological processes influencing the form and mobility of DOE contaminants in the subsurface".« less

Spatial Burnout in Water Reactors with Nonuniform Startup Distributions of Uranium and Boron

NASA Technical Reports Server (NTRS)

Fox, Thomas A.; Bogart, Donald

1955-01-01

Spatial burnout calculations have been made of two types of water moderated cylindrical reactor using boron as a burnable poison to increase reactor life. Specific reactors studied were a version of the Submarine Advanced Reactor (sAR) and a supercritical water reactor (SCW) . Burnout characteristics such as reactivity excursion, neutron-flux and heat-generation distributions, and uranium and boron distributions have been determined for core lives corresponding to a burnup of approximately 7 kilograms of fully enriched uranium. All reactivity calculations have been based on the actual nonuniform distribution of absorbers existing during intervals of core life. Spatial burnout of uranium and boron and spatial build-up of fission products and equilibrium xenon have been- considered. Calculations were performed on the NACA nuclear reactor simulator using two-group diff'usion theory. The following reactor burnout characteristics have been demonstrated: 1. A significantly lower excursion in reactivity during core life may be obtained by nonuniform rather than uniform startup distribution of uranium. Results for SCW with uranium distributed to provide constant radial heat generation and a core life corresponding to a uranium burnup of 7 kilograms indicated a maximum excursion in reactivity of 2.5 percent. This compared to a maximum excursion of 4.2 percent obtained for the same core life when w'anium was uniformly distributed at startup. Boron was incorporated uniformly in these cores at startup. 2. It is possible to approach constant radial heat generation during the life of a cylindrical core by means of startup nonuniform radial and axial distributions of uranium and boron. Results for SCW with nonuniform radial distribution of uranium to provide constant radial heat generation at startup and with boron for longevity indicate relatively small departures from the initially constant radial heat generation distribution during core life. Results for SAR with a sinusoidal distribution rather than uniform axial distributions of boron indicate significant improvements in axial heat generation distribution during the greater part of core life. 3. Uranium investments for cylindrical reactors with nonuniform radial uranium distributions which provide constant radial heat generation per unit core volume are somewhat higher than for reactors with uniform uranium concentration at startup. On the other hand, uranium investments for reactors with axial boron distributions which approach constant axial heat generation are somewhat smaller than for reactors with uniform boron distributions at startup.

High-Resolution Mineralogical Characterization and Biogeochemical Modeling of Uranium Reduction Pathways at the NABIR Field-Research Center

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

David R. Veblen; Chen Zhu; Lee Krumholz

The effectiveness and feasibility of bioremediation at the field scale cannot be fully assessed until the mechanisms of immobilization and U speciation in the solid matrix are resolved. However, characterization of the immobilized U and its valence states is extremely difficult, because microbially mediated mineral precipitates are generally nanometer (nm)-sized, poorly crystalline, or amorphous. We are developing combined field emission gun--scanning electron microscopy (FEG-SEM, at Indiana University) and FEG transmission electron microscopy (TEM, at Hopkins) to detect and isolate uranium containing phases; (1) method developments for TEM sample preparations and parallel electron energy loss spectroscopy (EELS) determination of uranium valence;more » and (2) to determine the speciation, fate, reactivity, valence states of immobilized uranium, using the state-of-the-art 300-kV, FEG-TEM. We have obtained preliminary results on contaminated sediments from Area 3 at the Oak Ridge Field Research Center (FRC). TEM results show that the sediments contain numerous minerals, including quartz, mica/clay (muscovite and/or illite), rutile, ilmenite, zircon, and an Al-Sr-Ce-Ca phosphate mineral, none of which contain uranium above the EDS detection limit. Substantial U (up to {approx}2 wt.%) is, however, clearly associated with two materials: (1) the Fe oxyhydroxide and (2) clots of a chemically complex material that is likely a mixture of several nm-scale phases. The Fe oxyhydroxide was identified as goethite from its polycrystalline SAED pattern and EDS analysis showing it to be very Fe-rich; the aggregate also displays one of several morphologies that are common for goethite. U is strongly sorbed to goethite in the FRC sediment, and the ubiquitous association with phosphorous suggests that complexes containing both U and P may play an important role in that sorption. Results from bulk analysis and SEM had previously demonstrated the association of U with Fe and thus suggested that U may be sorbed by Fe oxide or oxyhydroxide (Dr. Roh, image presented by David Watson). However, rigorous identification of the host minerals for U requires TEM results such as these involving imaging, electron diffraction, and spectroscopic analysis. An even higher concentration of U occurs in the chemically complex material noted above. These ''clots'' are high in Fe but also contain C, O, Mg, Al, Si, P, S, Cl, K, Ca, Mn, and U. This chemical complexity strongly suggests that they consist of aggregates of carbonate, silicate, phosphate, and sulfate phases, and TEM images also suggest that they may be intergrowths of numerous exceedingly small nanoparticles. EELS and EFTEM studies should be able to resolve these various components and identify precisely where the uranium is in these complex materials. From the results, it is clear that the FEG-SEM and FEG-TEM can readily detect uranium in the FRC samples. The FEG-SEM allows a wide field of view of the samples and can detect U-rich aggregates as small as 20-30 nm. The FEG-TEM can then focus on these aggregates and use SAED, EDS, EFTEM, and PEELS techniques to determine the valence states, structures, and compositional data for these aggregates. This research will provide a crucial component for a complete understanding of the efficacy of uranium bioremediation.« less

Biomining Microorganisms: Molecular Aspects and Applications in Biotechnology and Bioremediation

NASA Astrophysics Data System (ADS)

Jerez, Carlos A.

The microbial solubilization of metals using chemolithoautotrophic microorganisms has successfully been used in industrial processes called biomining to extract metals such as copper, gold, uranium and others. The most studied leaching bacteria are from the genus Acidithiobacillus belonging to the Gram-negative γ-proteobacteria. Acidithiobacillus spp. obtain their energy from the oxidation of ferrous iron, elemental sulfur, or partially oxidized sulfur compounds. Other thermophilic archaeons capable of oxidizing sulfur and iron (II) have also been known for many years, and they are mainly from the genera Sulfolobus, Acidianus, Metallosphaera and Sulfurisphaera. Recently, some mesophilic iron (II)-oxidizing archaeons such as Ferroplasma acidiphilium and F. acidarmanus belonging to the Thermoplasmales have also been isolated and characterized. Recent studies of microorganisms consider them in their consortia, integrating fundamental biological knowledge with metagenomics, metaproteomics, and other data to obtain a global picture of how a microbial community functions. The understanding of microbial growth and activities in oxidizing metal ions will be useful for improving applied microbial biotechnologies such as biomining, bioshrouding, biomonitoring and bioremediation of metals in acidic environments.

FINAL REPORT: Mechanistically-Base Field Scale Models of Uranium Biogeochemistry from Upscaling Pore-Scale Experiments and Models

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

Wood, Brian D.

2013-11-04

Biogeochemical reactive transport processes in the subsurface environment are important to many contemporary environmental issues of significance to DOE. Quantification of risks and impacts associated with environmental management options, and design of remediation systems where needed, require that we have at our disposal reliable predictive tools (usually in the form of numerical simulation models). However, it is well known that even the most sophisticated reactive transport models available today have poor predictive power, particularly when applied at the field scale. Although the lack of predictive ability is associated in part with our inability to characterize the subsurface and limitations inmore » computational power, significant advances have been made in both of these areas in recent decades and can be expected to continue. In this research, we examined the upscaling (pore to Darcy and Darcy to field) the problem of bioremediation via biofilms in porous media. The principle idea was to start with a conceptual description of the bioremediation process at the pore scale, and apply upscaling methods to formally develop the appropriate upscaled model at the so-called Darcy scale. The purpose was to determine (1) what forms the upscaled models would take, and (2) how one might parameterize such upscaled models for applications to bioremediation in the field. We were able to effectively upscale the bioremediation process to explain how the pore-scale phenomena were linked to the field scale. The end product of this research was to produce a set of upscaled models that could be used to help predict field-scale bioremediation. These models were mechanistic, in the sense that they directly incorporated pore-scale information, but upscaled so that only the essential features of the process were needed to predict the effective parameters that appear in the model. In this way, a direct link between the microscale and the field scale was made, but the upscaling process helped inform potential users of the model what kinds of information would be needed to accurately characterize the system.« less

Effects of aqueous uranyl speciation on the kinetics of microbial uranium reduction

DOE PAGES

Belli, Keaton M.; DiChristina, Thomas J.; Van Cappellen, Philippe; ...

2015-02-16

The ability to predict the success of the microbial reduction of soluble U(VI) to highly insoluble U(IV) as an in situ bioremediation strategy is complicated by the wide range of geochemical conditions at contaminated sites and the strong influence of aqueous uranyl speciation on the bioavailability and toxicity of U(VI) to metal-reducing bacteria. In order to determine the effects of aqueous uranyl speciation on uranium bioreduction kinetics, incubations and viability assays with Shewanella putrefaciens strain 200 were conducted over a range of pH and dissolved inorganic carbon (DIC), Ca 2+, and Mg 2+ concentrations. A speciation-dependent kinetic model was developedmore » to reproduce the observed time series of total dissolved uranium concentration over the range of geochemical conditions tested. The kinetic model yielded the highest rate constant for the reduction of uranyl non-carbonate species (i.e., the ‘free’ hydrated uranyl ion, uranyl hydroxides, and other minor uranyl complexes), indicating that they represent the most readily reducible fraction of U(VI) despite being the least abundant uranyl species in solution. In the presence of DIC, Ca 2+, and Mg 2+ is suppressed during the formation of more bioavailable uranyl non-carbonate species and resulted in slower bioreduction rates. At high concentrations of bioavailable U(VI), however, uranium toxicity to S. putrefaciens inhibited bioreduction, and viability assays confirmed that the concentration of non-carbonate uranyl species best predicts the degree of toxicity. The effect of uranium toxicity was accounted for by incorporating the free ion activity model of metal toxicity into the bioreduction rate law. These results demonstrate that, in the absence of competing terminal electron acceptors, uranium bioreduction kinetics can be predicted over a wide range of geochemical conditions based on the bioavailability and toxicity imparted on U(VI) by solution composition. Finally, these findings also imply that the concentration of uranyl non-carbonate species, despite being extremely low, is a determining factor controlling uranium bioreduction at contaminated sites.« less

Characterization and transcription of arsenic respiration and resistance genes during in situ uranium bioremediation

PubMed Central

Giloteaux, Ludovic; Holmes, Dawn E; Williams, Kenneth H; Wrighton, Kelly C; Wilkins, Michael J; Montgomery, Alison P; Smith, Jessica A; Orellana, Roberto; Thompson, Courtney A; Roper, Thomas J; Long, Philip E; Lovley, Derek R

2013-01-01

The possibility of arsenic release and the potential role of Geobacter in arsenic biogeochemistry during in situ uranium bioremediation was investigated because increased availability of organic matter has been associated with substantial releases of arsenic in other subsurface environments. In a field experiment conducted at the Rifle, CO study site, groundwater arsenic concentrations increased when acetate was added. The number of transcripts from arrA, which codes for the α-subunit of dissimilatory As(V) reductase, and acr3, which codes for the arsenic pump protein Acr3, were determined with quantitative reverse transcription-PCR. Most of the arrA (>60%) and acr3-1 (>90%) sequences that were recovered were most similar to Geobacter species, while the majority of acr3-2 (>50%) sequences were most closely related to Rhodoferax ferrireducens. Analysis of transcript abundance demonstrated that transcription of acr3-1 by the subsurface Geobacter community was correlated with arsenic concentrations in the groundwater. In contrast, Geobacter arrA transcript numbers lagged behind the major arsenic release and remained high even after arsenic concentrations declined. This suggested that factors other than As(V) availability regulated the transcription of arrA in situ, even though the presence of As(V) increased the transcription of arrA in cultures of Geobacter lovleyi, which was capable of As(V) reduction. These results demonstrate that subsurface Geobacter species can tightly regulate their physiological response to changes in groundwater arsenic concentrations. The transcriptomic approach developed here should be useful for the study of a diversity of other environments in which Geobacter species are considered to have an important influence on arsenic biogeochemistry. PMID:23038171

Functional environmental proteomics: elucidating the role of a c-type cytochrome abundant during uranium bioremediation

PubMed Central

Yun, Jiae; Malvankar, Nikhil S; Ueki, Toshiyuki; Lovley, Derek R

2016-01-01

Studies with pure cultures of dissimilatory metal-reducing microorganisms have demonstrated that outer-surface c-type cytochromes are important electron transfer agents for the reduction of metals, but previous environmental proteomic studies have typically not recovered cytochrome sequences from subsurface environments in which metal reduction is important. Gel-separation, heme-staining and mass spectrometry of proteins in groundwater from in situ uranium bioremediation experiments identified a putative c-type cytochrome, designated Geobacter subsurface c-type cytochrome A (GscA), encoded within the genome of strain M18, a Geobacter isolate previously recovered from the site. Homologs of GscA were identified in the genomes of other Geobacter isolates in the phylogenetic cluster known as subsurface clade 1, which predominates in a diversity of Fe(III)-reducing subsurface environments. Most of the gscA sequences recovered from groundwater genomic DNA clustered in a tight phylogenetic group closely related to strain M18. GscA was most abundant in groundwater samples in which Geobacter sp. predominated. Expression of gscA in a strain of Geobacter sulfurreducens that lacked the gene for the c-type cytochrome OmcS, thought to facilitate electron transfer from conductive pili to Fe(III) oxide, restored the capacity for Fe(III) oxide reduction. Atomic force microscopy provided evidence that GscA was associated with the pili. These results demonstrate that a c-type cytochrome with an apparent function similar to that of OmcS is abundant when Geobacter sp. are abundant in the subsurface, providing insight into the mechanisms for the growth of subsurface Geobacter sp. on Fe(III) oxide and suggesting an approach for functional analysis of other Geobacter proteins found in the subsurface. PMID:26140532

Characterization and Transcription of Arsenic Respiration and Resistance Genes During In Situ Uranium Bioremediation

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

Giloteaux, L.; Holmes, Dawn E.; Williams, Kenneth H.

2013-02-04

The possibility of arsenic release and the potential role of Geobacter in arsenic biogeochemistry during in situ uranium bioremediation was investigated because increased availability of organic matter has been associated with substantial releases of arsenic in other subsurface environments. In a field experiment conducted at the Rifle, CO study site, groundwater arsenic concentrations increased when acetate was added. The number of transcripts from arrA, which codes for the alpha subunit of dissimilatory As(V) reductase, and acr3, which codes for the arsenic pump protein Acr3, were determined with quantitative RT-PCR. Most of the arrA (> 60%) and acr3-1 (> 90%) sequencesmore » that were recovered were most similar to Geobacter species, while the majority of acr3-2 (>50%) sequences were most closely related to Rhodoferax ferrireducens. Analysis of transcript abundance demonstrated that transcription of acr3-1 by the subsurface Geobacter community was correlated with arsenic concentrations in the groundwater. In contrast, Geobacter arrA transcript numbers lagged behind the major arsenic release and remained high even after arsenic concentrations declined. This suggested that factors other than As(V) availability regulated transcription of arrA in situ even though the presence of As(V) increased transcription of arrA in cultures of G. lovleyi, which was capable of As(V) reduction. These results demonstrate that subsurface Geobacter species can tightly regulate their physiological response to changes in groundwater arsenic concentrations. The transcriptomic approach developed here should be useful for the study of a diversity of other environments in which Geobacter species are considered to have an important influence on arsenic biogeochemistry.« less

GROUNDWATER REMEDIATION SOLUTIONS AT HANFORD

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

Gilmore, Tyler J.; Truex, Michael J.; Williams, Mark D.

2007-02-26

In 2006, Congress provided funding to the U. S. Department of Energy (DOE) to study new technologies that could be used to treat contamination from the Hanford Site that might impact the Columbia River. The contaminants of concern are primarily metals and radionuclides, which are byproducts of Hanford’s cold war mission to produce plutonium for atomic weapons. The DOE asked Pacific Northwest National Laboratory (PNNL) to consider this problem and develop approaches to address the contamination that threatens the river. DOE identified three high priority sites that had groundwater contamination migrating towards the Columbia river for remediation. The contaminants includedmore » strontium-90, uranium and chromium. Remediation techniques for metals and radionuclides focus primarily on altering the oxidation state of the contaminant chemically or biologically, isolating the contaminants from the environment through adsorption or encapsulation or concentrating the contaminants for removal. A natural systems approach was taken that uses a mass balance concept to frame the problem and determine the most appropriate remedial approach. This approach provides for a scientifically based remedial decision. The technologies selected to address these contaminants included an apatite adsorption barrier coupled with a phytoremediation to address the strontium-90 contamination, injection of polyphosphate into the subsurface to sequester uranium, and a bioremediation approach to reduce chromium contamination in the groundwater. The ability to provide scientifically based approaches is in large part due to work developed under previous DOE Office of Science and Office of Environmental Management projects. For example, the polyphosphate and the bioremediation techniques, were developed by PNNL under the EMSP and NABIR programs. Contaminated groundwater under the Hanford Site poses a potential risk to humans and the Columbia River. These new technologies holds great promise for effectively remediating the residual waste that threatens the environment.« less

Functional environmental proteomics: elucidating the role of a c-type cytochrome abundant during uranium bioremediation.

PubMed

Yun, Jiae; Malvankar, Nikhil S; Ueki, Toshiyuki; Lovley, Derek R

2016-02-01

Studies with pure cultures of dissimilatory metal-reducing microorganisms have demonstrated that outer-surface c-type cytochromes are important electron transfer agents for the reduction of metals, but previous environmental proteomic studies have typically not recovered cytochrome sequences from subsurface environments in which metal reduction is important. Gel-separation, heme-staining and mass spectrometry of proteins in groundwater from in situ uranium bioremediation experiments identified a putative c-type cytochrome, designated Geobacter subsurface c-type cytochrome A (GscA), encoded within the genome of strain M18, a Geobacter isolate previously recovered from the site. Homologs of GscA were identified in the genomes of other Geobacter isolates in the phylogenetic cluster known as subsurface clade 1, which predominates in a diversity of Fe(III)-reducing subsurface environments. Most of the gscA sequences recovered from groundwater genomic DNA clustered in a tight phylogenetic group closely related to strain M18. GscA was most abundant in groundwater samples in which Geobacter sp. predominated. Expression of gscA in a strain of Geobacter sulfurreducens that lacked the gene for the c-type cytochrome OmcS, thought to facilitate electron transfer from conductive pili to Fe(III) oxide, restored the capacity for Fe(III) oxide reduction. Atomic force microscopy provided evidence that GscA was associated with the pili. These results demonstrate that a c-type cytochrome with an apparent function similar to that of OmcS is abundant when Geobacter sp. are abundant in the subsurface, providing insight into the mechanisms for the growth of subsurface Geobacter sp. on Fe(III) oxide and suggesting an approach for functional analysis of other Geobacter proteins found in the subsurface.

Groundwater remediation solutions at hanford

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

Gilmore, T.J.; Truex, M.J.; Williams, M.D.

2007-07-01

In 2006, Congress provided funding to the U. S. Department of Energy (DOE) to study new technologies that could be used to treat contamination from the Hanford Site that might impact the Columbia River. DOE identified three high priority sites that had groundwater contamination migrating towards the Columbia river for remediation. The contaminants included strontium-90, uranium and chromium. A natural systems approach was taken that uses a mass balance concept to frame the problem and determine the most appropriate remedial approach. This approach provides for a scientifically based remedial decision. The technologies selected to address these contaminants included an apatitemore » adsorption barrier coupled with a phyto-remediation to address the strontium-90 contamination, injection of polyphosphate into the subsurface to sequester uranium, and a bioremediation approach to reduce chromium contamination in the groundwater. The ability to provide scientifically based approaches to these sites was in large part due to work the Pacific Northwest National Laboratory developed under previous DOE Office of Science and Office of Environmental Management projects. (authors)« less

Spatial Modeling of Industrial Windfall on Soils to Detect Woody Species with Potential for Bioremediation

Treesearch

S. Salazar; M. Mendoza; A. M. Tejeda

2006-01-01

A spatial model is presented to explain the concentration of heavy metals (Fe, Cu, Zn, Ni, Cr, Co and Pb), in the soils around the industrial complex near the Port of Veracruz, Mexico. Unexpected low concentration sites where then tested to detect woody plant species that may have the capability to hiperacumulate these contaminants, hence having a potential for...

From Nanowires to Biofilms: An Exploration of Novel Mechanisms of Uranium Transformation Mediated by Geobacter Bacteria

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

REGUERA, GEMMA

2014-01-16

One promising strategy for the in situ bioremediation of radioactive groundwater contaminants that has been identified by the SBR Program is to stimulate the activity of dissimilatory metal-reducing microorganisms to reductively precipitate uranium and other soluble toxic metals. The reduction of U(VI) and other soluble contaminants by Geobacteraceae is directly dependent on the reduction of Fe(III) oxides, their natural electron acceptor, a process that requires the expression of Geobacter’s conductive pili (pilus nanowires). Expression of conductive pili by Geobacter cells leads to biofilm development on surfaces and to the formation of suspended biogranules, which may be physiological closer to biofilmsmore » than to planktonic cells. Biofilm development is often assumed in the subsurface, particularly at the matrix-well screen interface, but evidence of biofilms in the bulk aquifer matrix is scarce. Our preliminary results suggest, however, that biofilms develop in the subsurface and contribute to uranium transformations via sorption and reductive mechanisms. In this project we elucidated the mechanism(s) for uranium immobilization mediated by Geobacter biofilms and identified molecular markers to investigate if biofilm development is happening in the contaminated subsurface. The results provided novel insights needed in order to understand the metabolic potential and physiology of microorganisms with a known role in contaminant transformation in situ, thus having a significant positive impact in the SBR Program and providing novel concept to monitor, model, and predict biological behavior during in situ treatments.« less

Influence of Reactive Transport on the Reduction of U(VI) in the Presence of Fe(III) and Nitrate: Implications for U(VI) Immobilization by Bioremediation / Biobarriers- Final Report

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

B.D. Wood

2007-01-01

Subsurface contamination by metals and radionuclides represent some of the most challenging remediation problems confronting the Department of Energy (DOE) complex. In situ remediation of these contaminants by dissimilatory metal reducing bacteria (DMRB) has been proposed as a potential cost effective remediation strategy. The primary focus of this research is to determine the mechanisms by which the fluxes of electron acceptors, electron donors, and other species can be controlled to maximize the transfer of reductive equivalents to the aqueous and solid phases. The proposed research is unique in the NABIR portfolio in that it focuses on (i) the role ofmore » flow and transport in the initiation of biostimulation and the successful sequestration of metals and radionuclides [specifically U(VI)], (ii) the subsequent reductive capacity and stability of the reduced sediments produced by the biostimulation process, and (iii) the potential for altering the growth of biomass in the subsurface by the addition of specific metabolic uncoupling compounds. A scientifically-based understanding of these phenomena are critical to the ability to design successful bioremediation schemes. The laboratory research will employ Shewanella putrefaciens (CN32), a facultative DMRB that can use Fe(III) oxides as a terminal electron acceptor. Sediment-packed columns will be inoculated with this organism, and the reduction of U(VI) by the DMRB will be stimulated by the addition of a carbon and energy source in the presence of Fe(III). Separate column experiments will be conducted to independently examine: (1) the importance of the abiotic reduction of U(VI) by biogenic Fe(II); (2) the influence of the transport process on Fe(III) reduction and U(VI) immobilization, with emphasis on methods for controlling the fluxes of aqueous species to maximize uranium reduction; (3) the reductive capacity of biologically-reduced sediments (with respect to re-oxidation by convective fluxes of O2 and NO3-) and the long-term stability of immobilized uranium mineral phases after bioremediation processes are complete, and (4) the ability for metabolic uncoupling compounds to maintain microbial growth while limiting biomass production. The results of the laboratory experiments will be used to develop mathematical descriptive models for the coupled transport and reduction processes.« less

Heavy metal resistance strategies of acidophilic bacteria and their acquisition: importance for biomining and bioremediation.

PubMed

Navarro, Claudio A; von Bernath, Diego; Jerez, Carlos A

2013-01-01

Microbial solubilizing of metals in acid environments is successfully used in industrial bioleaching of ores or biomining to extract metals such as copper, gold, uranium and others. This is done mainly by acidophilic and other microorganisms that mobilize metals and generate acid mine drainage or AMD, causing serious environmental problems. However, bioremediation or removal of the toxic metals from contaminated soils can be achieved by using the specific properties of the acidophilic microorganisms interacting with these elements. These bacteria resist high levels of metals by using a few "canonical" systems such as active efflux or trapping of the metal ions by metal chaperones. Nonetheless, gene duplications, the presence of genomic islands, the existence of additional mechanisms such as passive instruments for pH and cation homeostasis in acidophiles and an inorganic polyphosphate-driven metal resistance mechanism have also been proposed. Horizontal gene transfer in environmental microorganisms present in natural ecosystems is considered to be an important mechanism in their adaptive evolution. This process is carried out by different mobile genetic elements, including genomic islands (GI), which increase the adaptability and versatility of the microorganism. This mini-review also describes the possible role of GIs in metal resistance of some environmental microorganisms of importance in biomining and bioremediation of metal polluted environments such as Thiomonas arsenitoxydans, a moderate acidophilic microorganism, Acidithiobacillus caldus and Acidithiobacillus ferrooxidans strains ATCC 23270 and ATCC 53993, all extreme acidophiles able to tolerate exceptionally high levels of heavy metals. Some of these bacteria contain variable numbers of GIs, most of which code for high numbers of genes related to metal resistance. In some cases there is an apparent correlation between the number of metal resistance genes and the metal tolerance of each of these microorganisms. It is expected that a detailed knowledge of the mechanisms that these environmental microorganisms use to adapt to their harsh niche will help to improve biomining and metal bioremediation in industrial processes.

Unexpected Interactions of the Cyanobacterial Metallothionein SmtA with Uranium.

PubMed

Acharya, Celin; Blindauer, Claudia A

2016-02-15

Molecules for remediating or recovering uranium from contaminated environmental resources are of high current interest, with protein-based ligands coming into focus recently. Metallothioneins either bind or redox-silence a range of heavy metals, conferring protection against metal stress in many organisms. Here, we report that the cyanobacterial metallothionein SmtA competes with carbonate for uranyl binding, leading to formation of heterometallic (UO2)(n)Zn4SmtA species, without thiol oxidation, zinc loss, or compromising secondary or tertiary structure of SmtA. In turn, only metalated and folded SmtA species were found to be capable of uranyl binding. (1)H NMR studies and molecular modeling identified Glu34/Asp38 and Glu12/C-terminus as likely adventitious, but surprisingly strong, bidentate binding sites. While it is unlikely that these interactions correspond to an evolved biological function of this metallothionein, their occurrence may offer new possibilities for designing novel multipurpose bacterial metallothioneins with dual ability to sequester both soft metal ions including Cu(+), Zn(2+), Cd(2+), Hg(2+), and Pb(2+) and hard, high-oxidation state heavy metals such as U(VI). The concomitant protection from the chemical toxicity of uranium may be valuable for the development of bacterial strains for bio-remediation.

Speciation and reactivity of uranium products formed during in situ bioremediation in a shallow alluvial aquifer.

PubMed

Alessi, Daniel S; Lezama-Pacheco, Juan S; Janot, Noémie; Suvorova, Elena I; Cerrato, José M; Giammar, Daniel E; Davis, James A; Fox, Patricia M; Williams, Kenneth H; Long, Philip E; Handley, Kim M; Bernier-Latmani, Rizlan; Bargar, John R

2014-11-04

In this study, we report the results of in situ U(VI) bioreduction experiments at the Integrated Field Research Challenge site in Rifle, Colorado, USA. Columns filled with sediments were deployed into a groundwater well at the site and, after a period of conditioning with groundwater, were amended with a mixture of groundwater, soluble U(VI), and acetate to stimulate the growth of indigenous microorganisms. Individual reactors were collected as various redox regimes in the column sediments were achieved: (i) during iron reduction, (ii) just after the onset of sulfate reduction, and (iii) later into sulfate reduction. The speciation of U retained in the sediments was studied using X-ray absorption spectroscopy, electron microscopy, and chemical extractions. Circa 90% of the total uranium was reduced to U(IV) in each reactor. Noncrystalline U(IV) comprised about two-thirds of the U(IV) pool, across large changes in microbial community structure, redox regime, total uranium accumulation, and reaction time. A significant body of recent research has demonstrated that noncrystalline U(IV) species are more suceptible to remobilization and reoxidation than crystalline U(IV) phases such as uraninite. Our results highlight the importance of considering noncrystalline U(IV) formation across a wide range of aquifer parameters when designing in situ remediation plans.

Speciation and Reactivity of Uranium Products Formed during in Situ Bioremediation in a Shallow Alluvial Aquifer

PubMed Central

2015-01-01

In this study, we report the results of in situ U(VI) bioreduction experiments at the Integrated Field Research Challenge site in Rifle, Colorado, USA. Columns filled with sediments were deployed into a groundwater well at the site and, after a period of conditioning with groundwater, were amended with a mixture of groundwater, soluble U(VI), and acetate to stimulate the growth of indigenous microorganisms. Individual reactors were collected as various redox regimes in the column sediments were achieved: (i) during iron reduction, (ii) just after the onset of sulfate reduction, and (iii) later into sulfate reduction. The speciation of U retained in the sediments was studied using X-ray absorption spectroscopy, electron microscopy, and chemical extractions. Circa 90% of the total uranium was reduced to U(IV) in each reactor. Noncrystalline U(IV) comprised about two-thirds of the U(IV) pool, across large changes in microbial community structure, redox regime, total uranium accumulation, and reaction time. A significant body of recent research has demonstrated that noncrystalline U(IV) species are more suceptible to remobilization and reoxidation than crystalline U(IV) phases such as uraninite. Our results highlight the importance of considering noncrystalline U(IV) formation across a wide range of aquifer parameters when designing in situ remediation plans. PMID:25265543

GEOPHYSICAL CHARACTERIZATION, REDOX ZONATION, AND CONTAMINANT DISTRIBUTION AT A GROUNDWATER/SURFACE WATER INTERFACE

EPA Science Inventory

Three transects along a groundwater/surface water interface were characterized for spatial distributions of chlorinated aliphatic hydrocarbons and geochemical conditions to evaluate the natural bioremediation potential of this environmental system. Partly on the basis of ground p...

Harnessing the power of microbial nanowires.

PubMed

Reguera, Gemma

2018-05-27

The reduction of iron oxide minerals and uranium in model metal reducers in the genus Geobacter is mediated by conductive pili composed primarily of a structurally divergent pilin peptide that is otherwise recognized, processed and assembled in the inner membrane by a conserved Type IVa pilus apparatus. Electronic coupling among the peptides is promoted upon assembly, allowing the discharge of respiratory electrons at rates that greatly exceed the rates of cellular respiration. Harnessing the unique properties of these conductive appendages and their peptide building blocks in metal bioremediation will require understanding of how the pilins assemble to form a protein nanowire with specialized sites for metal immobilization. Also important are insights into how cells assemble the pili to make an electroactive matrix and grow on electrodes as biofilms that harvest electrical currents from the oxidation of waste organic substrates. Genetic engineering shows promise to modulate the properties of the peptide building blocks, protein nanowires and current-harvesting biofilms for various applications. This minireview discusses what is known about the pilus material properties and reactions they catalyse and how this information can be harnessed in nanotechnology, bioremediation and bioenergy applications. © 2018 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Progress in understanding uranium(IV) speciation and dynamics in biologically reduced sediments: Research at molecular to centimeter scales by the SLAC SFA program

NASA Astrophysics Data System (ADS)

Bargar, J.; Williams, K. H.; Campbell, K. M.; Stubbs, J. E.; Suvorova, E.; Lezama-Pacheco, J. S.; Alessi, D.; Stylo, M.; Handley, K. M.; Bernier-Latmani, R.; Cerrato, J.; Davis, J. A.; Fox, P. M.; Giammar, D.; Long, P. E.

2011-12-01

The chemical and physical forms of U(IV) in reduced sediments, as well as the biogeochemical processes by which they form and transform, profoundly influence the stability of reduced U(IV) species and the behavior of uranium in biostimulated aquifers. Obtaining such information in field sediments is important because biogeochemical field conditions and their time dependence are difficult to replicate in the laboratory. The majority of contaminated aquifers in which bioremediation is of potential interest, including the Old Rifle, CO IFRC site, exhibit relatively low uranium sediment concentrations, i.e., < 10 ppm, presenting a formidable challenge to the use of spectroscopy and microscopy techniques that typically require 10-fold or higher uranium loadings. We have developed an in-situ column technique to study U(IV) species and evolving microbial communities in the Old Rifle aquifer and to correlate them with changes in trace and major ion groundwater composition during biostimulation treatments. Sediments were examined using x-ray and electron microscopy, x-ray absorption spectroscopy (XAS), and chemical extractions. XAS analysis showed that U(IV) occurred predominantly or exclusively as monomeric U(IV) complexes coordinated to oxo (or similar N/C) neighbors, and is associated with biomass or Fe sulfides. Even in the latter case, U(IV) was not coordinated directly to S neighbors. Sediment-hosted monomeric U(IV) complexes were found to partially transform into uraninite in the aquifer over a subsequent 12 month period. This work establishes the importance of monomeric U(IV) complexes in subsurface sediments at the Old Rifle site and provides a conceptual framework in which previously observed U(IV) reduction products can be related. These experiments also establish that U(IV) species are dynamic in aquifers and can undergo non-oxidative transformation reactions. These new results have important implications for uranium reactive transport models, long-term assessment of remediation technologies, and understanding natural uranium reduction in aquifers.

Microbial communities associated with uranium in-situ recovery mining process are related to acid mine drainage assemblages.

PubMed

Coral, Thomas; Descostes, Michaël; De Boissezon, Hélène; Bernier-Latmani, Rizlan; de Alencastro, Luiz Felippe; Rossi, Pierre

2018-07-01

A large fraction (47%) of the world's uranium is mined by a technique called "In Situ Recovery" (ISR). This mining technique involves the injection of a leaching fluid (acidic or alkaline) into a uranium-bearing aquifer and the pumping of the resulting solution through cation exchange columns for the recovery of dissolved uranium. The present study reports the in-depth alterations brought to autochthonous microbial communities during acidic ISR activities. Water samples were collected from a uranium roll-front deposit that is part of an ISR mine in operation (Tortkuduk, Kazakhstan). Water samples were obtained at a depth of ca 500 m below ground level from several zones of the Uyuk aquifer following the natural redox zonation inherited from the roll front deposit, including the native mineralized orebody and both upstream and downstream adjacent locations. Samples were collected equally from both the entrance and the exit of the uranium concentration plant. Next-generation sequencing data showed that the redox gradient shaped the community structures, within the anaerobic, reduced, and oligotrophic habitats of the native aquifer zones. Acid injection induced drastic changes in the structures of these communities, with a large decrease in both cell numbers and diversity. Communities present in the acidified (pH values < 2) mining areas exhibited similarities to those present in acid mine drainage, with the dominance of Sulfobacillus sp., Leptospirillum sp. and Acidithiobacillus sp., as well as the archaean Ferroplasma sp. Communities located up- and downstream of the mineralized zone under ISR and affected by acidic fluids were blended with additional facultative anaerobic and acidophilic microorganisms. These mixed biomes may be suitable communities for the natural attenuation of ISR mining-affected subsurface through the reduction of metals and sulfate. Assessing the effect of acidification on the microbial community is critical to evaluating the potential for natural attenuation or active bioremediation strategies. Copyright © 2018 Elsevier B.V. All rights reserved.

Multisource geological data mining and its utilization of uranium resources exploration

NASA Astrophysics Data System (ADS)

Zhang, Jie-lin

2009-10-01

Nuclear energy as one of clear energy sources takes important role in economic development in CHINA, and according to the national long term development strategy, many more nuclear powers will be built in next few years, so it is a great challenge for uranium resources exploration. Research and practice on mineral exploration demonstrates that utilizing the modern Earth Observe System (EOS) technology and developing new multi-source geological data mining methods are effective approaches to uranium deposits prospecting. Based on data mining and knowledge discovery technology, this paper uses multi-source geological data to character electromagnetic spectral, geophysical and spatial information of uranium mineralization factors, and provides the technical support for uranium prospecting integrating with field remote sensing geological survey. Multi-source geological data used in this paper include satellite hyperspectral image (Hyperion), high spatial resolution remote sensing data, uranium geological information, airborne radiometric data, aeromagnetic and gravity data, and related data mining methods have been developed, such as data fusion of optical data and Radarsat image, information integration of remote sensing and geophysical data, and so on. Based on above approaches, the multi-geoscience information of uranium mineralization factors including complex polystage rock mass, mineralization controlling faults and hydrothermal alterations have been identified, the metallogenic potential of uranium has been evaluated, and some predicting areas have been located.

Novel Sensor for the In Situ Measurement of Uranium Fluxes

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

Hatfield, Kirk

2015-02-10

The goal of this project was to develop a sensor that incorporates the field-tested concepts of the passive flux meter to provide direct in situ measures of flux for uranium and groundwater in porous media. Measurable contaminant fluxes [J] are essentially the product of concentration [C] and groundwater flux or specific discharge [q ]. The sensor measures [J] and [q] by changes in contaminant and tracer amounts respectively on a sorbent. By using measurement rather than inference from static parameters, the sensor can directly advance conceptual and computational models for field scale simulations. The sensor was deployed in conjunction withmore » DOE in obtaining field-scale quantification of subsurface processes affecting uranium transport (e.g., advection) and transformation (e.g., uranium attenuation) at the Rifle IFRC Site in Rifle, Colorado. Project results have expanded our current understanding of how field-scale spatial variations in fluxes of uranium, groundwater and salient electron donor/acceptors are coupled to spatial variations in measured microbial biomass/community composition, effective field-scale uranium mass balances, attenuation, and stability. The coupling between uranium, various nutrients and micro flora can be used to estimate field-scale rates of uranium attenuation and field-scale transitions in microbial communities. This research focuses on uranium (VI), but the sensor principles and design are applicable to field-scale fate and transport of other radionuclides. Laboratory studies focused on sorbent selection and calibration, along with sensor development and validation under controlled conditions. Field studies were conducted at the Rifle IFRC Site in Rifle, Colorado. These studies were closely coordinated with existing SBR (formerly ERSP) projects to complement data collection. Small field tests were conducted during the first two years that focused on evaluating field-scale deployment procedures and validating sensor performance under controlled field conditions. In the third and fourth year a suite of larger field studies were conducted. For these studies, the uranium flux sensor was used with uranium speciation measurements and molecular-biological tools to characterize microbial community and active biomass at synonymous wells distributed in a large grid. These field efforts quantified spatial changes in uranium flux and field-scale rates of uranium attenuation (ambient and stimulated), uranium stability, and quantitatively assessed how fluxes and effective reaction rates were coupled to spatial variations in microbial community and active biomass. Analyses of data from these field experiments were used to generate estimates of Monod kinetic parameters that are ‘effective’ in nature and optimal for modeling uranium fate and transport at the field-scale. This project provided the opportunity to develop the first sensor that provides direct measures of both uranium (VI) and groundwater flux. A multidisciplinary team was assembled to include two geochemists, a microbiologist, and two quantitative contaminant hydrologists. Now that the project is complete, the sensor can be deployed at DOE sites to evaluate field-scale uranium attenuation, source behavior, the efficacy of remediation, and off-site risk. Because the sensor requires no power, it can be deployed at remote sites for periods of days to months. The fundamental science derived from this project can be used to advance the development of predictive models for various transport and attenuation processes in aquifers. Proper development of these models is critical for long-term stewardship of contaminated sites in the context of predicting uranium source behavior, remediation performance, and off-site risk.« less

Diversity, metal resistance and uranium sequestration abilities of bacteria from uranium ore deposit in deep earth stratum.

PubMed

Islam, Ekramul; Sar, Pinaki

2016-05-01

Metal resistance and uranium (U) sequestration abilities of bacteria residing in subsurface U ore was investigated using 122 pure culture strains isolated through enrichment. The cumulative frequencies of isolates resistant to each metal tested were as follows: As(V), 74%; Zn, 58%; Ni, 53%; Cd, 47%; Cr(VI), 41%; Co, 40%; Cu, 20%; and Hg, 4%. 16S rRNA gene analysis revealed that isolated bacteria belonged to 14 genera with abundance of Arthrobacter, Microbacterium, Acinetobacter and Stenotrophomonas. Cobalt did not interfere with the growth of most of the bacterial isolates belonging to different groups while U allowed growth of four different genera of which Stenotrophomonas and Microbacterium showed high U tolerance. Interestingly, tolerance to Ni, Zn, Cu, and Hg was observed only in Microbacterium, Arthrobacter, Paenibacillus¸ and Acinetobacter, respectively. However, Microbacterium was found to be dominant when isolated from other five different metal enrichments including U. Uranium removal study showed that 84% of the test bacteria could remove more than 50mgUg(-1) dry weight from 80 or 160mgL(-1) U within 48h. In general, Microbacterium, Arthrobacter and Acinetobacter could remove a higher amount of U. High resolution transmission electron microscopy (HRTEM) study of U exposed cells revealed that accumulated U sequestered mostly around the cell periphery. The study highlights that indigenous U ore deposit bacteria have the potential to interact with U, and thus could be applied for bioremediation of U contaminated sites or wastes. Copyright © 2016 Elsevier Inc. All rights reserved.

High resolution remote sensing information identification for characterizing uranium mineralization setting in Namibia

NASA Astrophysics Data System (ADS)

Zhang, Jie-Lin; Wang, Jun-hu; Zhou, Mi; Huang, Yan-ju; Xuan, Yan-xiu; Wu, Ding

2011-11-01

The modern Earth Observation System (EOS) technology takes important role in the uranium geological exploration, and high resolution remote sensing as one of key parts of EOS is vital to characterize spectral and spatial information of uranium mineralization factors. Utilizing satellite high spatial resolution and hyperspectral remote sensing data (QuickBird, Radarsat2, ASTER), field spectral measurement (ASD data) and geological survey, this paper established the spectral identification characteristics of uranium mineralization factors including six different types of alaskite, lower and upper marble of Rössing formation, dolerite, alkali metasomatism, hematization and chloritization in the central zone of Damara Orogen, Namibia. Moreover, adopted the texture information identification technology, the geographical distribution zones of ore-controlling faults and boundaries between the different strata were delineated. Based on above approaches, the remote sensing geological anomaly information and image interpretation signs of uranium mineralization factors were extracted, the metallogenic conditions were evaluated, and the prospective areas have been predicted.

Spatial analysis techniques applied to uranium prospecting in Chihuahua State, Mexico

NASA Astrophysics Data System (ADS)

Hinojosa de la Garza, Octavio R.; Montero Cabrera, María Elena; Sanín, Luz H.; Reyes Cortés, Manuel; Martínez Meyer, Enrique

2014-07-01

To estimate the distribution of uranium minerals in Chihuahua, the advanced statistical model "Maximun Entropy Method" (MaxEnt) was applied. A distinguishing feature of this method is that it can fit more complex models in case of small datasets (x and y data), as is the location of uranium ores in the State of Chihuahua. For georeferencing uranium ores, a database from the United States Geological Survey and workgroup of experts in Mexico was used. The main contribution of this paper is the proposal of maximum entropy techniques to obtain the mineral's potential distribution. For this model were used 24 environmental layers like topography, gravimetry, climate (worldclim), soil properties and others that were useful to project the uranium's distribution across the study area. For the validation of the places predicted by the model, comparisons were done with other research of the Mexican Service of Geological Survey, with direct exploration of specific areas and by talks with former exploration workers of the enterprise "Uranio de Mexico". Results. New uranium areas predicted by the model were validated, finding some relationship between the model predictions and geological faults. Conclusions. Modeling by spatial analysis provides additional information to the energy and mineral resources sectors.

Supervised Machine Learning for Regionalization of Environmental Data: Distribution of Uranium in Groundwater in Ukraine

NASA Astrophysics Data System (ADS)

Govorov, Michael; Gienko, Gennady; Putrenko, Viktor

2018-05-01

In this paper, several supervised machine learning algorithms were explored to define homogeneous regions of con-centration of uranium in surface waters in Ukraine using multiple environmental parameters. The previous study was focused on finding the primary environmental parameters related to uranium in ground waters using several methods of spatial statistics and unsupervised classification. At this step, we refined the regionalization using Artifi-cial Neural Networks (ANN) techniques including Multilayer Perceptron (MLP), Radial Basis Function (RBF), and Convolutional Neural Network (CNN). The study is focused on building local ANN models which may significantly improve the prediction results of machine learning algorithms by taking into considerations non-stationarity and autocorrelation in spatial data.

Final Project Report, DE-SC0001280, Characterizing the Combined Roles of Iron and Transverse Mixing on Uranium Bioremediation in Groundwater using Microfluidic Devices

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

Finneran, Kevin; Werth, Charles; Strathmann, Timothy

2015-01-10

In situ bioremediation of U(VI) involves amending groundwater with an appropriate electron donor and limiting nutrients to promote biological reduction to the less soluble and mobile U(IV) oxidation state. Groundwater flow is laminar; mixing is controlled by hydrodynamic dispersion. Recent studies indicate that transverse dispersion along plume margins can limit mixing of the amended electron donor and accepter (such as U(VI) in remediation applications). As a result, microbial growth, and subsequently contaminant reaction, may be limited to these transverse mixing zones during bioremediation. The primary objective of this work was to characterize the combined effects of hydrology, geochemistry, and biologymore » on the (bio)remediation of U(VI). Our underlying hypothesis was that U(VI) reaction in groundwater is controlled by transverse mixing with an electron donor along plume margins, and that iron bioavailability in these zones affects U(VI) reduction kinetics and U(IV) re-oxidation. Our specific objectives were to a) quantify reaction kinetics mediated by biological versus geochemical reactions leading to U(VI) reduction and U(IV) re-oxidation, b) understand the influence of bioavailable iron on U(VI) reduction and U(IV) re-oxidation along the transverse mixing zones, c) determine how transverse mixing limitations and the presence of biomass in pores affects these reactions, and d) identify how microbial populations that develop along transverse mixing zones are influenced by the presence of iron and the concentration of electron donor. In the completed work, transverse mixing zones along plume margins were re-created in microfluidic pore networks, referred to as micromodels. We conducted a series of experiments that allowed us to distinguish among the hydraulic, biological, and geochemical mechanisms that contribute to U(VI) reduction, U(IV) re-oxidation, and U(VI) abiotic reaction with the limiting biological nutrient HP042-. This systematic approach may lead to a better understanding of U(VI) remediation, and better strategies for groundwater amendments to maximize remediation efficiency.« less

A Uranium Bioremediation Reactive Transport Benchmark

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

Yabusaki, Steven B.; Sengor, Sevinc; Fang, Yilin

A reactive transport benchmark problem set has been developed based on in situ uranium bio-immobilization experiments that have been performed at a former uranium mill tailings site in Rifle, Colorado, USA. Acetate-amended groundwater stimulates indigenous microorganisms to catalyze the reduction of U(VI) to a sparingly soluble U(IV) mineral. The interplay between the flow, acetate loading periods and rates, microbially-mediated and geochemical reactions leads to dynamic behavior in metal- and sulfate-reducing bacteria, pH, alkalinity, and reactive mineral surfaces. The benchmark is based on an 8.5 m long one-dimensional model domain with constant saturated flow and uniform porosity. The 159-day simulation introducesmore » acetate and bromide through the upgradient boundary in 14-day and 85-day pulses separated by a 10 day interruption. Acetate loading is tripled during the second pulse, which is followed by a 50 day recovery period. Terminal electron accepting processes for goethite, phyllosilicate Fe(III), U(VI), and sulfate are modeled using Monod-type rate laws. Major ion geochemistry modeled includes mineral reactions, as well as aqueous and surface complexation reactions for UO2++, Fe++, and H+. In addition to the dynamics imparted by the transport of the acetate pulses, U(VI) behavior involves the interplay between bioreduction, which is dependent on acetate availability, and speciation-controlled surface complexation, which is dependent on pH, alkalinity and available surface complexation sites. The general difficulty of this benchmark is the large number of reactions (74), multiple rate law formulations, a multisite uranium surface complexation model, and the strong interdependency and sensitivity of the reaction processes. Results are presented for three simulators: HYDROGEOCHEM, PHT3D, and PHREEQC.« less

Uranium plasma emission coefficient in the visible and near UV.

NASA Technical Reports Server (NTRS)

Mack, J. M., Jr.; Usher, J. L.; Schneider, R. T.; Campbell, H. D.

1971-01-01

Measurements of the specific emission coefficient in the near ultra-violet and visible region of a uranium arc plasma are reported. Spatial unfolding of the intensity profile is used to determine the emission coefficient in the spectral range of 2000 A to 6000 A. The uranium partial pressure is estimated to range between .001 and .01 atmosphere, and the corresponding temperature range is 5000 - 10,000 K.

Spatially Oscillating Activity and Microbial Succession of Mercury-Reducing Biofilms in a Technical-Scale Bioremediation System

PubMed Central

von Canstein, Harald; Li, Ying; Leonhäuser, Johannes; Haase, Elke; Felske, Andreas; Deckwer, Wolf-Dieter; Wagner-Döbler, Irene

2002-01-01

Mercury-contaminated chemical wastewater of a mercury cell chloralkali plant was cleaned on site by a technical-scale bioremediation system. Microbial mercury reduction of soluble Hg(II) to precipitating Hg(0) decreased the mercury load of the wastewater during its flow through the bioremediation system by up to 99%. The system consisted of a packed-bed bioreactor, where most of the wastewater's mercury load was retained, and an activated carbon filter, where residual mercury was removed from the bioreactor effluent by both physical adsorption and biological reduction. In response to the oscillation of the mercury concentration in the bioreactor inflow, the zone of maximum mercury reduction oscillated regularly between the lower and the upper bioreactor horizons or the carbon filter. At low mercury concentrations, maximum mercury reduction occurred near the inflow at the bottom of the bioreactor. At high concentrations, the zone of maximum activity moved to the upper horizons. The composition of the bioreactor and carbon filter biofilms was investigated by 16S-23S ribosomal DNA intergenic spacer polymorphism analysis. Analysis of spatial biofilm variation showed an increasing microbial diversity along a gradient of decreasing mercury concentrations. Temporal analysis of the bioreactor community revealed a stable abundance of two prevalent strains and a succession of several invading mercury-resistant strains which was driven by the selection pressure of high mercury concentrations. In the activated carbon filter, a lower selection pressure permitted a steady increase in diversity during 240 days of operation and the establishment of one mercury-sensitive invader. PMID:11916716

Microbial physiology-based model of ethanol metabolism in subsurface sediments

NASA Astrophysics Data System (ADS)

Jin, Qusheng; Roden, Eric E.

2011-07-01

A biogeochemical reaction model was developed based on microbial physiology to simulate ethanol metabolism and its influence on the chemistry of anoxic subsurface environments. The model accounts for potential microbial metabolisms that degrade ethanol, including those that oxidize ethanol directly or syntrophically by reducing different electron acceptors. Out of the potential metabolisms, those that are active in the environment can be inferred by fitting the model to experimental observations. This approach was applied to a batch sediment slurry experiment that examined ethanol metabolism in uranium-contaminated aquifer sediments from Area 2 at the U.S. Department of Energy Field Research Center in Oak Ridge, TN. According to the simulation results, complete ethanol oxidation by denitrification, incomplete ethanol oxidation by ferric iron reduction, ethanol fermentation to acetate and H 2, hydrogenotrophic sulfate reduction, and acetoclastic methanogenesis: all contributed significantly to the degradation of ethanol in the aquifer sediments. The assemblage of the active metabolisms provides a frame work to explore how ethanol amendment impacts the chemistry of the environment, including the occurrence and levels of uranium. The results can also be applied to explore how diverse microbial metabolisms impact the progress and efficacy of bioremediation strategies.

Femtosecond Laser Ablation Multicollector ICPMS Analysis of Uranium Isotopes in NIST Glass

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

Duffin, Andrew M.; Springer, Kellen WE; Ward, Jesse D.

We have utilized femtosecond laser ablation coupled to multi-collector inductively couple plasma mass spectrometry to measure the uranium isotopic content of NIST 61x (x=0,2,4,6) glasses. The uranium content of these glasses is a linear two-component mixing between isotopically natural uranium and the isotopically depleted spike used in preparing the glasses. Laser ablation results match extremely well, generally within a few ppm, with solution analysis following sample dissolution and chemical separation. In addition to isotopic data, sample utilization efficiency measurements indicate that over 1% of ablated uranium atoms reach a mass spectrometer detector, making this technique extremely efficient. Laser sampling alsomore » allows for spatial analysis and our data indicate that rare uranium concentration inhomogeneities exist in NIST 616 glass.« less

Enriched but not depleted uranium affects central nervous system in long-term exposed rat.

PubMed

Houpert, Pascale; Lestaevel, Philippe; Bussy, Cyrill; Paquet, François; Gourmelon, Patrick

2005-12-01

Uranium is well known to induce chemical toxicity in kidneys, but several other target organs, such as central nervous system, could be also affected. Thus in the present study, the effects on sleep-wake cycle and behavior were studied after chronic oral exposure to enriched or depleted uranium. Rats exposed to 4% enriched uranium for 1.5 months through drinking water, accumulated twice as much uranium in some key areas such as the hippocampus, hypothalamus and adrenals than did control rats. This accumulation was correlated with an increase of about 38% of the amount of paradoxical sleep, a reduction of their spatial working memory capacities and an increase in their anxiety. Exposure to depleted uranium for 1.5 months did not induce these effects, suggesting that the radiological activity induces the primary events of these effects of uranium.

Geophysical Monitoring of Coupled Microbial and Geochemical Processes During Stimulated Subsurface Bioremediation

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

Williams, Kenneth H.; Kemna, Andreas; Wilkins, Michael J.

2009-08-05

Understanding how microorganisms alter their physical and chemical environment during bioremediation is hindered by our inability to resolve subsurface microbial activity with high spatial resolution. Here we demonstrate the use of a minimally invasive geophysical technique to monitor stimulated microbial activity during acetate amendment in an aquifer near Rifle, Colorado. During electrical induced polarization (IP) measurements, spatiotemporal variations in the phase response between imposed electric current and the resultant electric field correlated with changes in groundwater geochemistry accompanying stimulated iron and sulfate reduction and sulfide mineral precipitation. The magnitude of the phase response varied with measurement frequency (0.125 and 1more » Hz) andwasdependent upon the dominant metabolic process. The spectral effect was corroborated using a biostimulated column experiment containing Rifle sediments and groundwater. Fluids and sediments recovered from regions exhibiting an anomalous phase response were enriched in Fe(II), dissolved sulfide, and cell-associated FeS nanoparticles. The accumulation of mineral precipitates and electroactive ions altered the ability of pore fluids to conduct electrical charge, accounting for the anomalous IP response and revealing the usefulness of multifrequency IP measurements for monitoring mineralogical and geochemical changes accompanying stimulated subsurface bioremediation.« less

Quantifying Temporal Autocorrelations for the Expression of Geobacter species mRNA Gene Transcripts at Variable Ammonium Levels during in situ U(VI) Bioremediation

NASA Astrophysics Data System (ADS)

Mouser, P. J.

2010-12-01

In order to develop decision-making tools for the prediction and optimization of subsurface bioremediation strategies, we must be able to link the molecular-scale activity of microorganisms involved in remediation processes with biogeochemical processes observed at the field-scale. This requires the ability to quantify changes in the in situ metabolic condition of dominant microbes and associate these changes to fluctuations in nutrient levels throughout the bioremediation process. It also necessitates a need to understand the spatiotemporal variability of the molecular-scale information to develop meaningful parameters and constraint ranges in complex bio-physio-chemical models. The expression of three Geobacter species genes (ammonium transporter (amtB), nitrogen fixation (nifD), and a housekeeping gene (recA)) were tracked at two monitoring locations that differed significantly in ammonium (NH4+) concentrations during a field-scale experiment where acetate was injected into the subsurface to simulate Geobacteraceae in a uranium-contaminated aquifer. Analysis of amtB and nifD mRNA transcript levels indicated that NH4+ was the primary form of fixed nitrogen during bioremediation. Overall expression levels of amtB were on average 8-fold higher at NH4+ concentrations of 300 μM or more than at lower NH4+ levels (average 60 μM). The degree of temporal correlation in Geobacter species mRNA expression levels was calculated at both locations using autocorrelation methods that describe the relationship between sample semi-variance and time lag. At the monitoring location with lower NH4+, a temporal correlation lag of 8 days was observed for both amtB and nifD transcript patterns. At the location where higher NH4+ levels were observed, no discernable temporal correlation lag above the sampling frequency (approximately every 2 days) was observed for amtB or nifD transcript fluctuations. Autocorrelation trends in recA expression levels at both locations indicated that while a temporal correlation in the general metabolic activity of Geobacter species may exist, considerable variability in transcript levels masked these correlations at the sampled scale. These findings suggest that when Geobacter species are dependent upon a particular nutrient such as NH4+, the time length for which their activity level relating to this nutrient condition can be predicted is significantly enhanced.

U.sup.+4 generation in HTER

DOEpatents

Miller, William E [Naperville, IL; Gay, Eddie C [Park Forest, IL; Tomczuk, Zygmunt [Homer Glen, IL

2006-03-14

A improved device and process for recycling spent nuclear fuels, in particular uranium metal, that facilitates the refinement and recovery of uranium metal from spent metallic nuclear fuels. The electrorefiner device comprises two anodes in predetermined spatial relation to a cathode. The anodese have separate current and voltage controls. A much higher voltage than normal for the electrorefining process is applied to the second anode, thereby facilitating oxidization of uranium (III), U.sup.+, to uranium (IV), U.sup.+4. The current path from the second anode to the cathode is physically shorter than the similar current path from the second anode to the spent nuclear fuel contained in a first anode shaped as a basket. The resulting U.sup.+4 oxidizes and solubilizes rough uranium deposited on the surface of the cathode. A softer uranium metal surface is left on the cathode and is more readily removed by a scraper.

BIOREMEDIATION OF PETROLEUM HYDROCARBONS: A FLEXIBLE VARIABLE SPEED TECHNOLOGY

EPA Science Inventory

The bioremediation of petroleum hydrocarbons has evolved into a number of different processes. These processes include in-situ aquifer bioremediation, bioventing, biosparging, passive bioremediation with oxygen release compounds, and intrinsic bioremediation. Although often viewe...

In situ Bioreduction of Uranium (VI) in Groundwater and Sediments with Edible Oil as the Electron Donor

NASA Astrophysics Data System (ADS)

Wu, W.; Watson, D. B.; Mehlhorn, T.; Zhang, G.; Earles, J.; Lowe, K.; Phillips, J.; Boyanov, M.; Kemner, K. M.; Schadt, C. W.; Brooks, S. C.; Criddle, C.; Jardine, P.

2009-12-01

In situ bioremediation of a uranium-contaminated aquifer was conducted at the US DOE Environmental Remediation Sciences Program (ERSP) Integrated Field Research Challenge (IFRC) site, in Oak Ridge, TN. Edible oil was tested as a slow-release electron donor for microbially mediated U (VI) reduction. Uranium contaminated sediments from the site were used in laboratory microcosm tests to study the feasibility of using this electron donor under anaerobic, ambient temperature conditions. Parallel microcosms were established using ethanol as electron donor for comparison. The tests also examined the impact of sulfate concentrations on U (VI) reduction. The oil was degraded by indigenous microorganisms with acetate as a major product but at a much slower rate than ethanol. The rapid removal of U (VI) from the aqueous phase occurred concurrently with acetate production and sulfate reduction. Initial U(VI) concentration in the aqueous phase increased with increased sulfate concentration (1 vs. 5 mM), likely due to U(VI) desorption from the solid phase, but more U(VI) was reduced with higher initial sulfate level. Finally, the bioreaction in microcosms progressed to methanogenesis. Subsequently, a field test with the edible oil was conducted in a highly permeable gravelly layer (hydraulic conductivity 0.076 cm/sec). Groundwater at the site contained 5-6 μM U; 1.0-1.2 mM sulfate; 3-4 mM Ca; pH 6.8. Diluted emulsified oil (20% solution) was injected into three injection wells within 2 hrs. Geochemical analysis of site groundwater demonstrated the sequential reduction of nitrate, Mn, Fe(III) and sulfate. Transient accumulation of acetate was observed as an intermediate in the oil degradation. Reduction and removal of uranium from groundwater was observed in all wells connected to the injection wells after 2-4 weeks. Uranium concentrations in groundwater were reduced to below 0.126 μM (EPA drinking water standard), at some well locations. Rebound of U in groundwater was observed together with the rebound of sulfate concentrations as the oil was consumed. Uranium (VI) reduction to U (IV) in the microcosm and in situ field tests was confirmed by X-ray near-edge absorption spectroscopy analysis. Bacterial populations in microcosms and field samples were analyzed using 16S rRNA gene libraries and Geochip analysis.

Uranium Interaction with Two Multi-Resistant Environmental Bacteria: Cupriavidus metallidurans CH34 and Rhodopseudomonas palustris

PubMed Central

Llorens, Isabelle; Untereiner, Guillaume; Jaillard, Danielle; Gouget, Barbara; Chapon, Virginie; Carriere, Marie

2012-01-01

Depending on speciation, U environmental contamination may be spread through the environment or inversely restrained to a limited area. Induction of U precipitation via biogenic or non-biogenic processes would reduce the dissemination of U contamination. To this aim U oxidation/reduction processes triggered by bacteria are presently intensively studied. Using X-ray absorption analysis, we describe in the present article the ability of Cupriavidus metallidurans CH34 and Rhodopseudomonas palustris, highly resistant to a variety of metals and metalloids or to organic pollutants, to withstand high concentrations of U and to immobilize it either through biosorption or through reduction to non-uraninite U(IV)-phosphate or U(IV)-carboxylate compounds. These bacterial strains are thus good candidates for U bioremediation strategies, particularly in the context of multi-pollutant or mixed-waste contaminations. PMID:23251623

Microbial copper resistance: importance in biohydrometallurgy.

PubMed

Martínez-Bussenius, Cristóbal; Navarro, Claudio A; Jerez, Carlos A

2017-03-01

Industrial biomining has been extensively used for many years to recover valuable metals such as copper, gold, uranium and others. Furthermore, microorganisms involved in these processes can also be used to bioremediate places contaminated with acid and metals. These uses are possible due to the great metal resistance that these extreme acidophilic microorganisms possess. In this review, the most recent findings related to copper resistance mechanisms of bacteria and archaea related to biohydrometallurgy are described. The recent search for novel metal resistance determinants is not only of scientific interest but also of industrial importance, as reflected by the genomic sequencing of microorganisms present in mining operations and the search of those bacteria with extreme metal resistance to improve the extraction processes used by the biomining companies. © 2016 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Uranium in groundwater--Fertilizers versus geogenic sources.

PubMed

Liesch, Tanja; Hinrichsen, Sören; Goldscheider, Nico

2015-12-01

Due to its radiological and toxicological properties even at low concentration levels, uranium is increasingly recognized as relevant contaminant in drinking water from aquifers. Uranium originates from different sources, including natural or geogenic, mining and industrial activities, and fertilizers in agriculture. The goal of this study was to obtain insights into the origin of uranium in groundwater while differentiating between geogenic sources and fertilizers. A literature review concerning the sources and geochemical processes affecting the occurrence and distribution of uranium in the lithosphere, pedosphere and hydrosphere provided the background for the evaluation of data on uranium in groundwater at regional scale. The state of Baden-Württemberg, Germany, was selected for this study, because of its hydrogeological and land-use diversity, and for reasons of data availability. Uranium and other parameters from N=1935 groundwater monitoring sites were analyzed statistically and geospatially. Results show that (i) 1.6% of all water samples exceed the German legal limit for drinking water (10 μg/L); (ii) The range and spatial distribution of uranium and occasional peak values seem to be related to geogenic sources; (iii) There is a clear relation between agricultural land-use and low-level uranium concentrations, indicating that fertilizers generate a measurable but low background of uranium in groundwater. Copyright © 2015 Elsevier B.V. All rights reserved.

Regularities of spatial association of major endogenous uranium deposits and kimberlitic dykes in the uranium ore regions of the Ukrainian Shield

NASA Astrophysics Data System (ADS)

Kalashnyk, Anna

2015-04-01

During exploration works we discovered the spatial association and proximity time formation of kimberlite dykes (ages are 1,815 and 1,900 Ga for phlogopite) and major industrial uranium deposits in carbonate-sodium metasomatites (age of the main uranium ore of an albititic formation is 1,85-1,70 Ga according to U-Pb method) in Kirovogradsky, Krivorozhsky and Alekseevsko-Lysogorskiy uranium ore regions of the Ukrainian Shield (UkrSh) [1]. In kimberlites of Kirovogradsky ore region uranium content reaches 18-20 g/t. Carbon dioxide is a major component in the formation of hydrothermal uranium deposits and the formation of the sodium in the process of generating the spectrum of alkaline ultrabasic magmas in the range from picritic to kimberlite and this is the connection between these disparate geochemical processes. For industrial uranium deposits in carbonate-sodium metasomatitics of the Kirovogradsky and Krivorozhsky uranium ore regions are characteristic of uranyl carbonate introduction of uranium, which causes correlation between CO2 content and U in range of "poor - ordinary - rich" uranium ore. In productive areas of uranium-ore fields of the Kirovogradsky ore region for phlogopite-carbonate veinlets of uranium ore albitites deep δ13C values (from -7.9 to -6.9o/oo) are characteristic. Isotope-geochemical investigation of albitites from Novokonstantynovskoe, Dokuchaevskoe, Partyzanskoe uranium deposits allowed obtaining direct evidence of the involvement of mantle material during formation of uranium albitites in Kirovogradsky ore region [2]. Petrological characteristics of kimberlites from uranium ore regions of the UkrSh (presence of nodules of dunite and harzburgite garnet in kimberlites, diamonds of peridotite paragenesis, chemical composition of indicator minerals of kimberlite, in particular Gruzskoy areas pyropes (Cr2O3 = 6,1-7,1%, MgO = 19,33-20,01%, CaO = 4,14-4,38 %, the content of knorringite component of most grains > 50mol%), chromites (Cr2O3 = 45,32-62,17%, MgO = 7,3-12,5%) allow us to estimate the depth of generation of kimberlite magmas more than 170-200 km. Ilmenites show two groups according to MgO, Cr2O3 and TiO2 content. Reconstructions of the mantle sections show also two intervals of pressures divided at 4.5 GPa, the upper part is highly metasomatized This high degree metasomatism is determined for almost all mantle columns. It is suggested that large-scale of uranium-bearing mantle fluids may be associated with the ancient degasation during the subduction which is highly enriched in U component . Analysis of the reasons for the marked association kimberlitic dykes and major industrial uranium deposits in carbonate-sodium metasomatic in the UkrSh led to the conclusion that hydrothermal uranium deposits are confined to the supply mantle fluid systems of mantle fault zones exercising brings sodium carbonate solutions enriched uranium from mantle sources. References: 1. Kalashnik A.A. New prognostic-evaluation criteria in technology prognosis of forming industrial endogenous uranium deposits of the Ukrainian Shield, 2014. Scientific proceedings of UkrSGRI, № 2, p. 27-54 (in Russian) 2. Stepanjuk L.M., Bondarenko S.V., Somka V.O. and other, 2012. Source of uranium and uranium-bearing sodium albitites for example of Dokuchaievskogo field of the Ingulsky megablock of the UkrSh: Abstracts of scientific conference "Theoretical issues and research practice metasomatic rocks and ores" (Kyiv, 14-16 March 2012), IGMOF, p.78-80. (in Ukrainian)

Integrated Geophysical Measurements for Bioremediation Monitoring: Combining Spectral Induced Polarization, Nuclear Magnetic Resonance and Magnetic Methods

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

Keating, Kristina; Slater, Lee; Ntarlagiannis, Dimitris

2015-02-24

This documents contains the final report for the project "Integrated Geophysical Measurements for Bioremediation Monitoring: Combining Spectral Induced Polarization, Nuclear Magnetic Resonance and Magnetic Methods" (DE-SC0007049) Executive Summary: Our research aimed to develop borehole measurement techniques capable of monitoring subsurface processes, such as changes in pore geometry and iron/sulfur geochemistry, associated with remediation of heavy metals and radionuclides. Previous work has demonstrated that geophysical method spectral induced polarization (SIP) can be used to assess subsurface contaminant remediation; however, SIP signals can be generated from multiple sources limiting their interpretation value. Integrating multiple geophysical methods, such as nuclear magnetic resonance (NMR)more » and magnetic susceptibility (MS), with SIP, could reduce the ambiguity of interpretation that might result from a single method. Our research efforts entails combining measurements from these methods, each sensitive to different mineral forms and/or mineral-fluid interfaces, providing better constraints on changes in subsurface biogeochemical processes and pore geometries significantly improving our understanding of processes impacting contaminant remediation. The Rifle Integrated Field Research Challenge (IFRC) site was used as a test location for our measurements. The Rifle IFRC site is located at a former uranium ore-processing facility in Rifle, Colorado. Leachate from spent mill tailings has resulted in residual uranium contamination of both groundwater and sediments within the local aquifer. Studies at the site include an ongoing acetate amendment strategy, native microbial populations are stimulated by introduction of carbon intended to alter redox conditions and immobilize uranium. To test the geophysical methods in the field, NMR and MS logging measurements were collected before, during, and after acetate amendment. Next, laboratory NMR, MS, and SIP measurements were collected on columns of Rifle sediments during acetate amendment. The laboratory experiments were designed to simulate the field experiments; changes in geophysical signals were expected to correlate with changes in redox conditions and iron speciation. Field MS logging measurements revealed vertically stratified magnetic mineralization, likely the result of detrital magnetic fraction within the bulk alluvium. Little to no change was observed in the MS data suggesting negligible production of magnetic phases (e.g. magnetite, pyrrhotite) as a result of sulfidogenesis. Borehole NMR measurements contained high levels of noise contamination requiring significant signal processing, and analysis suggests that any changes may be difficult to differentiate from simultaneous changes in water content. Laboratory MS and NMR measurements remained relatively stable throughout the course of the acetate amendment experiment, consistent with field measurements. However, SIP measurements changed during the acetate amendment associated with the formation of iron-sulfide mineral phases; a finding that is consistent with chemical analysis of the solid phase materials in the columns.« less

Uranium association with iron-bearing phases in mill tailings from Gunnar, Canada.

PubMed

Othmane, Guillaume; Allard, Thierry; Morin, Guillaume; Sélo, Madeleine; Brest, Jessica; Llorens, Isabelle; Chen, Ning; Bargar, John R; Fayek, Mostafa; Calas, Georges

2013-11-19

The speciation of uranium was studied in the mill tailings of the Gunnar uranium mine (Saskatchewan, Canada), which operated in the 1950s and 1960s. The nature, quantification, and spatial distribution of uranium-bearing phases were investigated by chemical and mineralogical analyses, fission track mapping, electron microscopy, and X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopies at the U LIII-edge and Fe K-edge. In addition to uranium-containing phases from the ore, uranium is mostly associated with iron-bearing minerals in all tailing sites. XANES and EXAFS data and transmission electron microscopy analyses of the samples with the highest uranium concentrations (∼400-700 mg kg(-1) of U) demonstrate that uranium primarily occurs as monomeric uranyl ions (UO2(2+)), forming inner-sphere surface complexes bound to ferrihydrite (50-70% of the total U) and to a lesser extent to chlorite (30-40% of the total U). Thus, the stability and mobility of uranium at the Gunnar site are mainly influenced by sorption/desorption processes. In this context, acidic pH or alkaline pH with the presence of UO2(2+)- and/or Fe(3+)-complexing agents (e.g., carbonate) could potentially solubilize U in the tailings pore waters.

Bicarbonate Impact on U(VI) Bioreduction in a Shallow Alluvial Aquifer

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

Long, Philip E.; Williams, Kenneth H.; Davis, James A.

Field-scale biostimulation and desorption tracer experiments conducted in a uranium (U) contaminated, shallow alluvial aquifer have provided insight into the coupling of microbiology, biogeochemistry, and hydrogeology that control U mobility in the subsurface. Initial experiments successfully tested the concept that Fe-reducing bacteria such as Geobacter sp. could enzymatically reduce soluble U(VI) to insoluble U(IV) during in situ electron donor amendment (Anderson et al. 2003, Williams et al. 2011). In parallel, in situ desorption tracer tests using bicarbonate amendment demonstrated rate-limited U(VI) desorption (Fox et al. 2012). These results and prior laboratory studies underscored the importance of enzymatic U(VI)-reduction and suggestedmore » the ability to combine desorption and bioreduction of U(VI). Here we report the results of a new field experiment in which bicarbonate-promoted uranium desorption and acetate amendment were combined and compared to an acetate amendment-only experiment in the same experimental plot. Results confirm that bicarbonate amendment to alluvial aquifer desorbs U(VI) and increases the abundance of Ca-uranyl-carbonato complexes. At the same time, that the rate of acetate-promoted enzymatic U(VI) reduction was greater in the presence of added bicarbonate in spite of the increased dominance of Ca-uranyl-carbonato aqueous complexes. A model-simulated peak rate of U(VI) reduction was ~3.8 times higher during acetate-bicarbonate treatment than under acetate-only conditions. Lack of consistent differences in microbial community structure between acetate-bicarbonate and acetate-only treatments suggest that a significantly higher rate of U(VI) reduction the bicarbonate-impacted sediment may be due to a higher intrinsic rate of microbial reduction induced by elevated concentrations of the bicarbonate oxyanion. The findings indicate that bicarbonate amendment may be useful in improving the engineered bioremediation of uranium in aquifers.« less

Bicarbonate impact on U(VI) bioreduction in a shallow alluvial aquifer

NASA Astrophysics Data System (ADS)

Long, Philip E.; Williams, Kenneth H.; Davis, James A.; Fox, Patricia M.; Wilkins, Michael J.; Yabusaki, Steven B.; Fang, Yilin; Waichler, Scott R.; Berman, Elena S. F.; Gupta, Manish; Chandler, Darrell P.; Murray, Chris; Peacock, Aaron D.; Giloteaux, Ludovic; Handley, Kim M.; Lovley, Derek R.; Banfield, Jillian F.

2015-02-01

Field-scale biostimulation and desorption tracer experiments conducted in a uranium (U) contaminated, shallow alluvial aquifer have provided insight into the coupling of microbiology, biogeochemistry, and hydrogeology that control U mobility in the subsurface. Initial experiments successfully tested the concept that Fe-reducing bacteria such as Geobacter sp. could enzymatically reduce soluble U(VI) to insoluble U(IV) during in situ electron donor amendment (Anderson et al., 2003; Williams et al., 2011). In parallel, in situ desorption tracer tests using bicarbonate amendment demonstrated rate-limited U(VI) desorption (Fox et al., 2012). These results and prior laboratory studies underscored the importance of enzymatic U(VI)-reduction and suggested the ability to combine desorption and bioreduction of U(VI). Here we report the results of a new field experiment in which bicarbonate-promoted uranium desorption and acetate amendment were combined and compared to an acetate amendment-only experiment in the same experimental plot. Results confirm that bicarbonate amendment to alluvial aquifer sediments desorbs U(VI) and increases the abundance of Ca-uranyl-carbonato complexes. At the same time, the rate of acetate-promoted enzymatic U(VI) reduction was greater in the presence of added bicarbonate in spite of the increased dominance of Ca-uranyl-carbonato aqueous complexes. A model-simulated peak rate of U(VI) reduction was ∼3.8 times higher during acetate-bicarbonate treatment than under acetate-only conditions. Lack of consistent differences in microbial community structure between acetate-bicarbonate and acetate-only treatments suggest that a significantly higher rate of U(VI) reduction in the bicarbonate-impacted sediment may be due to a higher intrinsic rate of microbial reduction induced by elevated concentrations of the bicarbonate oxyanion. The findings indicate that bicarbonate amendment may be useful in improving the engineered bioremediation of uranium in aquifers.

Biosorption of metal and salt tolerant microbial isolates from a former uranium mining area. Their impact on changes in rare earth element patterns in acid mine drainage.

PubMed

Haferburg, Götz; Merten, Dirk; Büchel, Georg; Kothe, Erika

2007-12-01

The concentration of metals in microbial habitats influenced by mining operations can reach enormous values. Worldwide, much emphasis is placed on the research of resistance and biosorptive capacities of microorganisms suitable for bioremediation purposes. Using a collection of isolates from a former uranium mining area in Eastern Thuringia, Germany, this study presents three Gram-positive bacterial strains with distinct metal tolerances. These strains were identified as members of the genera Bacillus, Micrococcus and Streptomyces. Acid mine drainage (AMD) originating from the same mining area is characterized by high metal concentrations of a broad range of elements and a very low pH. AMD was analyzed and used as incubation solution. The sorption of rare earth elements (REE), aluminum, cobalt, copper, manganese, nickel, strontium, and uranium through selected strains was studied during a time course of four weeks. Biosorption was investigated after one hour, one week and four weeks by analyzing the concentrations of metals in supernatant and biomass. Additionally, dead biomass was investigated after four weeks of incubation. The maximum of metal removal was reached after one week. Up to 80% of both Al and Cu, and more than 60% of U was shown to be removed from the solution. High concentrations of metals could be bound to the biomass, as for example 2.2 mg/g U. The strains could survive four weeks of incubation. Distinct and different patterns of rare earth elements of the inoculated and non-inoculated AMD water were observed. Changes in REE patterns hint at different binding types of heavy metals regarding incubation time and metabolic activity of the cells. (c) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Profiling microbial community structures across six large oilfields in China and the potential role of dominant microorganisms in bioremediation.

PubMed

Sun, Weimin; Li, Jiwei; Jiang, Lei; Sun, Zhilei; Fu, Meiyan; Peng, Xiaotong

2015-10-01

Successful bioremediation of oil pollution is based on a comprehensive understanding of the in situ physicochemical conditions and indigenous microbial communities as well as the interaction between microorganisms and geochemical variables. Nineteen oil-contaminated soil samples and five uncontaminated controls were taken from six major oilfields across different geoclimatic regions in China to investigate the spatial distribution of the microbial ecosystem. Microbial community analysis revealed remarkable variation in microbial diversity between oil-contaminated soils taken from different oilfields. Canonical correspondence analysis (CCA) further demonstrated that a suite of in situ geochemical parameters, including soil moisture and sulfate concentrations, were among the factors that influenced the overall microbial community structure and composition. Phylogenetic analysis indicated that the vast majority of sequences were related to the genera Arthrobacter, Dietzia, Pseudomonas, Rhodococcus, and Marinobacter, many of which contain known oil-degrading or oil-emulsifying species. Remarkably, a number of archaeal genera including Halalkalicoccus, Natronomonas, Haloterrigena, and Natrinema were found in relatively high abundance in some of the oil-contaminated soil samples, indicating that these Euryarchaeota may play an important ecological role in some oil-contaminated soils. This study offers a direct and reliable reference of the diversity of the microbial community in various oil-contaminated soils and may influence strategies for in situ bioremediation of oil pollution.

Hydrologic and Temporal Influences of Evaporite Minerals on the Vertical Distribution, Storage, and Mobility of Uranium

NASA Astrophysics Data System (ADS)

Roycroft, S. J.; Noel, V.; Boye, K.; Besancon, C.; Weaver, K. L.; Johnson, R. H.; Dam, W. L.; Fendorf, S. E.; Bargar, J.

2016-12-01

Uranium contaminated groundwater in Riverton, Wyoming persists despite anticipated natural attenuation outside of a former uranium ore processing facility. The inability of natural flushing to dilute the uranium below the regulatory threshold indicates that sediments act as secondary sources likely (re)supplying uranium to groundwater. Throughout the contaminated floodplain, uranium rich-evaporites are readily abundant in the upper 2 m of sediments and are spatially coincident with the location of the plume, which suggests a likely link between evaporites and increased uranium levels. Knowledge of where and how uranium is stored within evaporite-associated sediments is required to understand processes controlling the mobility of uranium. We expect that flooding and seasonal changes in hydrologic conditions will affect U phase partitioning, and thus largely control U mobility. The primary questions we are addressing in this project are: What is the relative abundance of uranium incorporated in various mineral complexes throughout the evaporite sediments? How do the factors of depth, location, and seasonality influence the relative incorporation, mobility and speciation of uranium?We have systematically sampled from two soil columns over three dates in Riverton. The sampling dates span before and after a significant flooding event, providing insight into the flood's impact on local uranium mobility. Sequential chemical extractions are used to decipher the reactivity of uranium and approximate U operationally defined within reactants targeting carbonate, silicate, organic, and metal oxide bound or water and exchangeable phases. Extractions throughout the entirety of the sediment cores provide a high-resolution vertical profile of the distribution of uranium in various extracted phases. Throughout the profile, the majority (50-60%) of uranium is bound within carbonate-targeted extracts, a direct effect of the carbonate-rich evaporite sediments. The sum of our analyses provide a dynamic model of uranium incorporation within evaporite sediments holding implications for the fate of uranium throughout contaminated sites across the Colorado River Basin.

40 CFR 300.915 - Data requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... this section. (d) Bioremediation Agents. (1) Name, brand, or trademark, if any, under which the agent...) Bioremediation Agent Effectiveness. Use bioremediation agent effectiveness test methods described in appendix C to part 300. (8) Bioremediation Agent Toxicity [Reserved]. (9) Biological additives. (i) For...

Spatial Variation and Assessment of Heavy Metal and Radioactive Risk in Farmland around a Retired Uranium Mine

NASA Astrophysics Data System (ADS)

Liang, Jie; Shi, Chen-hao; Zeng, Guang-ming; Zhong, Min-zhou; Yuan, Yu-jie

2017-07-01

In recent years, heavy metal contamination in the environment has been attracted worldwide attention due to their toxicity, persistence,extensive sources and non-biodegradable properties. We herein investigate variation trend and risk of heavy metal and radiation distribution in the former mine stope, former mineral ore stockyard, and mine road with surface soils of a retired uranium mine in the mid-south of China. The mean concentrations (mg/kg) of Pb,Cd,Cu,Zn,As,Hg,Cr,Mn,Ni,U, and 232Th were analyzed according to the corresponding background values in Hunan, China. The Geo-accumulation index (Igeo ) were used for the assessment of pollution level of heavy metals and the radioactive elements of U and 232Th. Then, Pollution load index (PLI) and GIS techniquewere integrated to assess spatial distribution of heavy metal contamination and radioactive contamination. Results confirmed that three areas in the retired uranium mine was a primary source of pollution, which showed anthropogenic origin mainly from agricultural runoff, hydrometallurgy from chemical industries, radioactive tailings, and electroplating industriesfinally drained into Zishui River and Xiangjiang River. Based on the actual situation, some suggestions were put forward for the treatment of the retired uranium mine in conclusion.

Spatial variability and geochemistry of rare earth elements in soils from the largest uranium-phosphate deposit of Brazil.

PubMed

Cunha, Cleyton Saialy Medeiros; da Silva, Ygor Jacques Agra Bezerra; Escobar, Maria Eugenia Ortiz; do Nascimento, Clístenes Williams Araújo

2018-02-22

The Itataia uranium-phosphate deposit is the largest uranium reserve in Brazil. Rare earth elements (REEs) are commonly associated with phosphate deposits; however, there are no studies on the concentrations of REEs in soils of the Itataia deposit region. Thus, the objective of the research was to evaluate the concentration and spatial variability of REEs in topsoils of Itataia phosphate deposit region. In addition, the influence of soil properties on the geochemistry of REEs was investigated. Results showed that relatively high mean concentrations (mg kg -1 ) of heavy REEs (Gd 6.01; Tb 1.25; Ho 1.15; Er 4.05; Tm 0.64; Yb 4.61; Lu 0.65) were found in surface soils samples. Soil properties showed weak influence on the geochemical behavior of REEs in soils, except for the clay content. On the other hand, parent material characteristics, such as P and U, had strong influence on REEs concentrations. Spatial distribution patterns of REEs in soils are clearly associated with P and U contents. Therefore, geochemical surveys aiming at the delineation of ore-bearing zones in the region can benefit from our data. The results of this work reinforce the perspective for co-mining of P, U and REEs in this important P-U reserve.

Physico-Chemical Heterogeneity of Organic-Rich Sediments in the Rifle Aquifer, CO: Impact on Uranium Biogeochemistry.

PubMed

Janot, Noémie; Lezama Pacheco, Juan S; Pham, Don Q; O'Brien, Timothy M; Hausladen, Debra; Noël, Vincent; Lallier, Florent; Maher, Kate; Fendorf, Scott; Williams, Kenneth H; Long, Philip E; Bargar, John R

2016-01-05

The Rifle alluvial aquifer along the Colorado River in west central Colorado contains fine-grained, diffusion-limited sediment lenses that are substantially enriched in organic carbon and sulfides, as well as uranium, from previous milling operations. These naturally reduced zones (NRZs) coincide spatially with a persistent uranium groundwater plume. There is concern that uranium release from NRZs is contributing to plume persistence or will do so in the future. To better define the physical extent, heterogeneity and biogeochemistry of these NRZs, we investigated sediment cores from five neighboring wells. The main NRZ body exhibited uranium concentrations up to 100 mg/kg U as U(IV) and contains ca. 286 g of U in total. Uranium accumulated only in areas where organic carbon and reduced sulfur (as iron sulfides) were present, emphasizing the importance of sulfate-reducing conditions to uranium retention and the essential role of organic matter. NRZs further exhibited centimeter-scale variations in both redox status and particle size. Mackinawite, greigite, pyrite and sulfate coexist in the sediments, indicating that dynamic redox cycling occurs within NRZs and that their internal portions can be seasonally oxidized. We show that oxidative U(VI) release to the aquifer has the potential to sustain a groundwater contaminant plume for centuries. NRZs, known to exist in other uranium-contaminated aquifers, may be regionally important to uranium persistence.

Final Scientific Report: Bacterial Nanowires and Extracellular Electron Transfer to Heavy Metals and Radionuclides by Bacterial Isolates from DOE Field Research Centers

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

Nealson, Kenneth

This proposal involved the study of bacteria capable of transferring electrons from the bacterial cells to electron acceptors located outside the cell. These could be either insoluble minerals that were transformed into soluble products upon the addition of electrons, or they could be soluble salts like uranium or chromium, that become insoluble upon the addition of electrons. This process is called extracellular electron transport or EET, and can be done directly by cellular contact, or via conductive appendages called bacterial nanowires. In this work we examined a number of different bacteria for their ability to perform EET, and also lookedmore » at their ability to produce conductive nanowires that can be used for EET at a distance away from the EET-capable cells. In the work, new bacteria were isolated, new abilities of EET were examined, and many new methods were developed, and carefully described in the literature. These studies set the stage for future work dealing with the bioremediation of toxic metals like uranium and chromium. They also point out that EET (and conductive nanowires) are far more common that had been appreciated, and may be involved with energy transfer not only in sediments, but in symbioses between different bacteria, and in symbiosis/pathogenesis between bacteria and higher organisms.« less

New Catalytic DNA Biosensors for Radionuclides and Metal ion

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

Yi Lu

2008-03-01

We aim to develop new DNA biosensors for simultaneous detection and quantification of bioavailable radionuclides, such as uranium, technetium, and plutonium, and metal contaminants, such as lead, chromium, and mercury. The sensors will be highly sensitive and selective. They will be applied to on-site, real-time assessment of concentration, speciation, and stability of the individual contaminants before and during bioremediation, and for long-term monitoring of DOE contaminated sites. To achieve this goal, we have employed a combinatorial method called “in vitro selection” to search from a large DNA library (~ 1015 different molecules) for catalytic DNA molecules that are highly specificmore » for radionuclides or other metal ions through intricate 3-dimensional interactions as in metalloproteins. Comprehensive biochemical and biophysical studies have been performed on the selected DNA molecules. The findings from these studies have helped to elucidate fundamental principles for designing effective sensors for radionuclides and metal ions. Based on the study, the DNA have been converted to fluorescent or colorimetric sensors by attaching to it fluorescent donor/acceptor pairs or gold nanoparticles, with 11 part-per-trillion detection limit (for uranium) and over million fold selectivity (over other radionuclides and metal ions tested). Practical application of the biosensors for samples from the Environmental Remediation Sciences Program (ERSP) Field Research Center (FRC) at Oak Ridge has also been demonstrated.« less

7 CFR 3201.63 - Bioremediation materials.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 15 2012-01-01 2012-01-01 false Bioremediation materials. 3201.63 Section 3201.63... Designated Items § 3201.63 Bioremediation materials. (a) Definition. Dry or liquid solutions (including those... with this part, will give a procurement preference for qualifying biobased bioremediation materials. By...

7 CFR 3201.63 - Bioremediation materials.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 15 2013-01-01 2013-01-01 false Bioremediation materials. 3201.63 Section 3201.63... Designated Items § 3201.63 Bioremediation materials. (a) Definition. Dry or liquid solutions (including those... with this part, will give a procurement preference for qualifying biobased bioremediation materials. By...

7 CFR 3201.63 - Bioremediation materials.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 15 2014-01-01 2014-01-01 false Bioremediation materials. 3201.63 Section 3201.63... Designated Items § 3201.63 Bioremediation materials. (a) Definition. Dry or liquid solutions (including those... with this part, will give a procurement preference for qualifying biobased bioremediation materials. By...

76 FR 10918 - License Transfer Order for the Cimarron Facility at Crescent, OK

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-28

... groundwater remediation including natural attenuation, excavation, bioremediation, and the use of... bioremediation. The NRC staff conducted an expanded acceptance review of the December 11, 2006, bioremediation..., Cimarron Corporation submitted a revised license amendment request for the use of bioremediation and...

Spatial distribution of environmental risk associated to a uranium abandoned mine (Central Portugal)

NASA Astrophysics Data System (ADS)

Antunes, I. M.; Ribeiro, A. F.

2012-04-01

The abandoned uranium mine of Canto do Lagar is located at Arcozelo da Serra, central Portugal. The mine was exploited in an open pit and produced about 12430Kg of uranium oxide (U3O8), between 1987 and 1988. The dominant geological unit is the porphyritic coarse-grained two-mica granite, with biotite>muscovite. The uranium deposit consists of two gaps crushing, parallel to the coarse-grained porphyritic granite, with average direction N30°E, silicified, sericitized and reddish jasperized, with a width of approximately 10 meters. These gaps are accompanied by two thin veins of white quartz, 70°-80° WNW, ferruginous and jasperized with chalcedony, red jasper and opal. These veins are about 6 meters away from each other. They contain secondary U-phosphates phases such as autunite and torbernite. Rejected materials (1000000ton) were deposited on two dumps and a lake was formed in the open pit. To assess the environmental risk of the abandoned uranium mine of Canto do Lagar, were collected and analysed 70 samples on stream sediments, soils and mine tailings materials. The relation between samples composition were tested using the Principal Components Analysis (PCA) (multivariate analysis) and spatial distribution using Kriging Indicator. The spatial distribution of stream sediments shows that the probability of expression for principal component 1 (explaining Y, Zr, Nb, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Hf, Th and U contents), decreases along SE-NW direction. This component is explained by the samples located inside mine influence. The probability of expression for principal component 2 (explaining Be, Na, Al, Si, P, K, Ca, Ti, Mn, Fe, Co, Ni, Cu, As, Rb, Sr, Mo, Cs, Ba, Tl and Bi contents), increases to middle stream line. This component is explained by the samples located outside mine influence. The spatial distribution of soils, shows that the probability of expression for principal component 1 (explaining Mg, P, Ca, Ge, Sr, Y, Zr, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, W, Th and U contents) decreases along SE direction and increases along NE and SW directions. The probability of expression for principal component 2 (explaining pH, K, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr and Pb contents), decreases from central points (inside mine influence) to peripheral points (outside mine influence) and gradually increases along N and SW directions. The spatial distribution of tailing materials did not allowed a consistent spatial distribution. In general, the stream sediments are classified as unpolluted and not polluted or moderately polluted, according to geoaccumulation Müller index with exception of local samples, located inside mine influence. The soils cannot be used for public, private or residential uses according to the Canadian soil legislation. However, almost samples can be used for commercial or industrial occupation. According to the target values and intervention values for soils remediation, these soils need intervention. Tailing materials samples are much polluted in thorium (Th) and uranium (U) and they cannot be used for public, private or residential uses.

75 FR 19385 - Agency Information Collection Activities; Proposed Collection; Comment Request; National Oil and...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-14

..., but are not limited to, manufacturers of bioremediation agents, dispersants, surface collecting agents... the Schedule. In addition, at 40 CFR 300.915(d), EPA requires respondents to test bioremediation... Bioremediation Agent Effectiveness Test is used to compare the effectiveness of different bioremediation agents...

Uranium metallogenesis of the peraluminous leucogranite from the Pontivy-Rostrenen magmatic complex (French Armorican Variscan belt): the result of long-term oxidized hydrothermal alteration during strike-slip deformation

NASA Astrophysics Data System (ADS)

Ballouard, C.; Poujol, M.; Mercadier, J.; Deloule, E.; Boulvais, P.; Baele, J. M.; Cuney, M.; Cathelineau, M.

2018-06-01

In the French Armorican Variscan belt, most of the economically significant hydrothermal U deposits are spatially associated with peraluminous leucogranites emplaced along the south Armorican shear zone (SASZ), a dextral lithospheric scale wrench fault that recorded ductile deformation from ca. 315 to 300 Ma. In the Pontivy-Rostrenen complex, a composite intrusion, the U mineralization is spatially associated with brittle structures related to deformation along the SASZ. In contrast to monzogranite and quartz monzodiorite (3 < U < 9 ppm; Th/U > 3), the leucogranite samples are characterized by highly variable U contents ( 3 to 27 ppm) and Th/U ratios ( 0.1 to 5) suggesting that the crystallization of magmatic uranium oxide in the more evolved facies was followed by uranium oxide leaching during hydrothermal alteration and/or surface weathering. U-Pb dating of uranium oxides from the deposits reveals that they mostly formed between ca. 300 and 270 Ma. In monzogranite and quartz monzodiorite, apatite grains display magmatic textures and provide U-Pb ages of ca. 315 Ma reflecting the time of emplacement of the intrusions. In contrast, apatite grains from the leucogranite display textural, geochemical, and geochronological evidences for interaction with U-rich oxidized hydrothermal fluids contemporaneously with U mineralizing events. From 300 to 270 Ma, infiltration of surface-derived oxidized fluids leached magmatic uranium oxide from fertile leucogranite and formed U deposits. This phenomenon was sustained by brittle deformation and by the persistence of thermal anomalies associated with U-rich granitic bodies.

DEMONSTRATION BULLETIN: NEW YORK STATE MULTI-VENDOR BIOREMEDIATION - R.E. WRIGHT ENVIRONMENTAL, INC.'S IN-SITU BIOREMEDIATION TREATMENT SYSTEM

EPA Science Inventory

The R.E. Wright Environmental, Inc.‘s (REWEI) In-situ Bioremediation Treatment System is an in-situ bioremediation technology for the treatment of soils contaminated with organic compounds. According to the Developer, contaminated soils are remediated in-situ by stimulating the a...

Bioremediation techniques-classification based on site of application: principles, advantages, limitations and prospects.

PubMed

Azubuike, Christopher Chibueze; Chikere, Chioma Blaise; Okpokwasili, Gideon Chijioke

2016-11-01

Environmental pollution has been on the rise in the past few decades owing to increased human activities on energy reservoirs, unsafe agricultural practices and rapid industrialization. Amongst the pollutants that are of environmental and public health concerns due to their toxicities are: heavy metals, nuclear wastes, pesticides, green house gases, and hydrocarbons. Remediation of polluted sites using microbial process (bioremediation) has proven effective and reliable due to its eco-friendly features. Bioremediation can either be carried out ex situ or in situ, depending on several factors, which include but not limited to cost, site characteristics, type and concentration of pollutants. Generally, ex situ techniques apparently are more expensive compared to in situ techniques as a result of additional cost attributable to excavation. However, cost of on-site installation of equipment, and inability to effectively visualize and control the subsurface of polluted sites are of major concerns when carrying out in situ bioremediation. Therefore, choosing appropriate bioremediation technique, which will effectively reduce pollutant concentrations to an innocuous state, is crucial for a successful bioremediation project. Furthermore, the two major approaches to enhance bioremediation are biostimulation and bioaugmentation provided that environmental factors, which determine the success of bioremediation, are maintained at optimal range. This review provides more insight into the two major bioremediation techniques, their principles, advantages, limitations and prospects.

Implications of Bioremediation of Polycyclic Aromatic Hydrocarbon-Contaminated Soils for Human Health and Cancer Risk

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

Davie-Martin, Cleo L.; Stratton, Kelly G.; Teeguarden, Justin G.

Background: Bioremediation uses microorganisms to degrade polycyclic aromatic hydrocarbons (PAHs) in contaminated soils. Its success is largely evaluated through targeted analysis of PAH concentrations in soil and cancer risk (exposure) estimates. However, bioremediation often fails to significantly degrade the most carcinogenic PAHs and can initiate formation of more polar metabolites, some of which may be more toxic. Objectives: We aimed to investigate whether the cancer risk associated with PAH-contaminated soils was reduced post-bioremediation and to identify the most effective bioremediation strategies for degrading the carcinogenic and high molecular weight (≥MW302) PAHs. Methods: Pre- and post-bioremediation concentrations of eight B2 groupmore » carcinogenic PAHs in soils were collated from the literature and used to calculate excess lifetime cancer risks (ELCR) for adult populations exposed via non-dietary ingestion, per current U.S. Environmental Protection Agency (USEPA) recommendations. Due to the nature of the collated data (reported as mean concentrations ± standard deviations pre- and post-bioremediation), we used simulation methods to reconstruct the datasets and enable statistical comparison of ELCR values pre- and post-bioremediation. Additionally, we measured MW302 PAHs in a contaminated soil prior to and following treatment in an aerobic bioreactor and examined their contributions to cancer risk. Results: 120 of 158 treated soils (76%) exhibited a statistically significant reduction in cancer risk following bioremediation; however, 67% (106/158) of soils had post-bioremediation ELCR values over 10 fold higher than the USEPA health-based ‘acceptable’ risk level. Composting treatments were most effective at biodegrading PAHs in soils and reducing the ELCR. MW302 PAHs were not significantly degraded during bioremediation and dibenzo(a,l)pyrene, alone, contributed an additional 35% to the cancer risk associated with the eight B2 group PAHs in the same bioremediated soil. Conclusions: Bioremediation strategies often fail to reduce carcinogenic PAH concentrations in contaminated soils below USEPA acceptable cancer risk levels. Additionally, MW302 PAHs and ‘unknown’ metabolites (compounds not routinely measured) are not included in current cancer risk assessments and could significantly contribute to soil carcinogenicity.« less

Uranium-series constraints on radionuclide transport and groundwater flow at the Nopal I uranium deposit, Sierra Pena Blanca, Mexico.

PubMed

Goldstein, Steven J; Abdel-Fattah, Amr I; Murrell, Michael T; Dobson, Patrick F; Norman, Deborah E; Amato, Ronald S; Nunn, Andrew J

2010-03-01

Uranium-series data for groundwater samples from the Nopal I uranium ore deposit were obtained to place constraints on radionuclide transport and hydrologic processes for a nuclear waste repository located in fractured, unsaturated volcanic tuff. Decreasing uranium concentrations for wells drilled in 2003 are consistent with a simple physical mixing model that indicates that groundwater velocities are low ( approximately 10 m/y). Uranium isotopic constraints, well productivities, and radon systematics also suggest limited groundwater mixing and slow flow in the saturated zone. Uranium isotopic systematics for seepage water collected in the mine adit show a spatial dependence which is consistent with longer water-rock interaction times and higher uranium dissolution inputs at the front adit where the deposit is located. Uranium-series disequilibria measurements for mostly unsaturated zone samples indicate that (230)Th/(238)U activity ratios range from 0.005 to 0.48 and (226)Ra/(238)U activity ratios range from 0.006 to 113. (239)Pu/(238)U mass ratios for the saturated zone are <2 x 10(-14), and Pu mobility in the saturated zone is >1000 times lower than the U mobility. Saturated zone mobility decreases in the order (238)U approximately (226)Ra > (230)Th approximately (239)Pu. Radium and thorium appear to have higher mobility in the unsaturated zone based on U-series data from fractures and seepage water near the deposit.

The dendroanalysis of oak trees as a method of biomonitoring past and recent contamination in an area influenced by uranium mining.

PubMed

Märten, Arno; Berger, Dietrich; Köhler, Mirko; Merten, Dirk

2015-12-01

We reconstructed the contamination history of an area influenced by 40 years of uranium mining and subsequent remediation actions using dendroanalysis (i.e., the determination of the elemental content of tree rings). The uranium content in the tree rings of four individual oak trees (Quercus sp.) was determined by laser ablation with inductively coupled plasma mass spectrometry (LA-ICP-MS). This technique allows the investigation of trace metals in solid samples with a spatial resolution of 250 μm and a detection limit below 0.01 μg/g for uranium. The investigations show that in three of the four oaks sampled, there were temporally similar uranium concentrations. These were approximately 2 orders of magnitude higher (0.15 to 0.4 μg/g) than those from before the period of active mining (concentrations below 0.01 μg/g). After the mining was terminated and the area was restored, the uranium contents in the wood decreased by approximately 1 order of magnitude. The similar radial uranium distribution patterns of the three trees were confirmed by correlation analysis. In combination with the results of soil analyses, it was determined that there was a heterogeneous contamination in the forest investigated. This could be confirmed by pre-remediation soil uranium contents from literature. The uranium contents in the tree rings of the oaks investigated reflect the contamination history of the study area. This study demonstrates that the dendrochemical analysis of oak tree rings is a suitable technique for investigating past and recent uranium contamination in mining areas.

Optimized Enhanced Bioremediation Through 4D Geophysical Monitoring and Autonomous Data Collection, Processing and Analysis

DTIC Science & Technology

2014-09-01

ER-200717) Optimized Enhanced Bioremediation Through 4D Geophysical Monitoring and Autonomous Data Collection, Processing and Analysis...N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE Optimized Enhanced Bioremediation Through 4D Geophysical Monitoring and Autonomous Data...8 2.1.2 The Geophysical Signatures of Bioremediation ......................................... 8 2.2 PRIOR

Cleaning up with genomics: applying molecular biology to bioremediation.

PubMed

Lovley, Derek R

2003-10-01

Bioremediation has the potential to restore contaminated environments inexpensively yet effectively, but a lack of information about the factors controlling the growth and metabolism of microorganisms in polluted environments often limits its implementation. However, rapid advances in the understanding of bioremediation are on the horizon. Researchers now have the ability to culture microorganisms that are important in bioremediation and can evaluate their physiology using a combination of genome-enabled experimental and modelling techniques. In addition, new environmental genomic techniques offer the possibility for similar studies on as-yet-uncultured organisms. Combining models that can predict the activity of microorganisms that are involved in bioremediation with existing geochemical and hydrological models should transform bioremediation from a largely empirical practice into a science.

A record of uranium-series transport at Nopal I, Sierra Pena Blanca, Mexico: Implications for natural uranium deposits and radioactive waste repositories

DOE PAGES

Denton, J. S.; Goldstein, S. J.; Paviet, P.; ...

2016-04-10

Studies of uranium-series (U-series) disequilibria within and around ore deposits provide valuable information on the extent and timing of actinide mobility, via mineral-fluid interaction, over a range of spatial and temporal scales. Such information is useful in studies of analogs of high-level nuclear-waste repositories, as well as for mining and mineral extraction sites, locations of previous nuclear weapons testing, and legacy nuclear waste contamination. In this study we present isotope dilution mass spectrometry U-series measurements for fracture-fill materials (hematite, goethite, kaolinite, calcite, dolomite and quartz) from one such analog; the Nopal I uranium ore deposit situated at Peña Blanca inmore » the Chihuahua region of northern Mexico. The ore deposit is located in fractured, unsaturated volcanic tuff and fracture-fill materials from surface fractures as well as fractures in a vertical drill core have been analyzed. High uranium concentrations in the fracture-fill materials (between 12 and 7700 ppm) indicate uranium mobility and transport from the deposit. Furthermore, uranium concentrations generally decrease with horizontal distance away from the deposit but in this deposit there is no trend with depth below the surface.« less

Microstructure effects on the recrystallization of low-symmetry alpha-uranium

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

McCabe, Rodney James; Richards, Andrew Walter; Coughlin, Daniel Robert

2015-10-01

We employ electron backscatter diffraction (EBSD) to investigate microstructural evolution of uranium during recrystallization. To understand the relationship between microstructure and recrystallization, we use measures of intra-granular misorientation within grains and near grain boundaries in both deformed (non-recrystallized) uranium and recrystallizing uranium. The data show that the level of intra-granular misorientation depends on crystallographic orientation. However, contrary to expectation, this relationship does not significantly affect the recrystallization texture. Rather, the analysis suggests that recrystallization nucleation occurs along high angle grain boundaries in the deformed microstructure. Specifically, we show that the nucleation of recrystallized grains correlates well with the spatially heterogeneousmore » distribution of high angle boundaries. Due to the inhomogeneous distribution of high angle boundaries, the recrystallized microstructure after long times exhibits clustered distributions of small and large grains. Twin boundaries do not appear to act as recrystallization nucleation sites.« less

U-Th-Pb systematics of some granitoids from the northeastern Yilgarn Block, Western Australia and implications for uranium source rock potential.

USGS Publications Warehouse

Stuckless, J.S.; Bunting, J.A.; Nkomo, I.T.

1981-01-01

The Mount Boreas-type granite and spatially associated syenitic granitoid of Western Australia yield Pb/Pb ages of 2370+ or -100Ma and 2760+ or -210Ma, respectively. Th/Pb ages, although less precise, are concordant with these ages, and therefore the apparent ages are interpreted to be the crystallisation ages for these two units. U/Pb ages are variable and for the most part anomalously old, which suggests a Cainozoic uranium loss. However, this loss is generally small (<3mu g/g); therefore, neither granitoid in its fresh state provides a good source for nearby calcrete-hosted uranium deposits. The possibility remains that the Mount Boreas- type granite that has been completely weathered during the Tertiary could have been a source for the calcrete-type uranium deposits in W.A. Although the Mount Boreas-type granite is highly fractionated, it does not bear a strong geochemical imprint of a sedimentary precursor. This feature contrasts it with apparently fresh granitoids from other parts of the world that have lost large amounts of uranium (approx 20mu g/g) and are associated with large roll-type and other low temperature-type uranium deposits.-Authors

A model of early formation of uranium molecular oxides in laser-ablated plasmas

NASA Astrophysics Data System (ADS)

Finko, Mikhail; Curreli, Davide; Azer, Magdi; Weisz, David; Crowhurst, Jonathan; Rose, Timothy; Koroglu, Batikan; Radousky, Harry; Zaug, Joseph; Armstrong, Mike

2017-10-01

An important problem within the field of nuclear forensics is fractionation: the formation of post-detonation nuclear debris whose composition does not reflect that of the source weapon. We are investigating uranium fractionation in rapidly cooling plasma using a combined experimental and modeling approach. In particular, we use laser ablation of uranium metal samples to produce a low-temperature plasma with physical conditions similar to a condensing nuclear fireball. Here we present a first plasma-chemistry model of uranium molecular species formation during the early stage of laser ablated plasma evolution in atmospheric oxygen. The system is simulated using a global kinetic model with rate coefficients calculated according to literature data and the application of reaction rate theory. The model allows for a detailed analysis of the evolution of key uranium molecular species and represents the first step in producing a uranium fireball model that is kinetically validated against spatially and temporally resolved spectroscopy measurements. This project was sponsored by the DoD, Defense Threat Reduction Agency, Grant HDTRA1-16- 1-0020. This work was performed in part under the auspices of the U.S. DoE by Lawrence Livermore National Laboratory under Contract DE-AC52- 07NA27344.

Endophytic microorganisms--promising applications in bioremediation of greenhouse gases.

PubMed

Stępniewska, Z; Kuźniar, A

2013-11-01

Bioremediation is a technique that uses microbial metabolism to remove pollutants. Various techniques and strategies of bioremediation (e.g., phytoremediation enhanced by endophytic microorganisms, rhizoremediation) can mainly be used to remove hazardous waste from the biosphere. During the last decade, this specific technique has emerged as a potential cleanup tool only for metal pollutants. This situation has changed recently as a possibility has appeared for bioremediation of other pollutants, for instance, volatile organic compounds, crude oils, and radionuclides. The mechanisms of bioremediation depend on the mobility, solubility, degradability, and bioavailability of contaminants. Biodegradation of pollutions is associated with microbial growth and metabolism, i.e., factors that have an impact on the process. Moreover, these factors have a great influence on degradation. As a result, recognition of natural microbial processes is indispensable for understanding the mechanisms of effective bioremediation. In this review, we have emphasized the occurrence of endophytic microorganisms and colonization of plants by endophytes. In addition, the role of enhanced bioremediation by endophytic bacteria and especially of phytoremediation is presented.

Bioremediation Education Science and Technology (BEST) Program Annual Report 1999

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

Hazen, Terry C.

2000-07-01

The Bioremediation, Education, Science and Technology (BEST) partnership provides a sustainable and contemporary approach to developing new bioremedial technologies for US Department of Defense (DoD) priority contaminants while increasing the representation of underrepresented minorities and women in an exciting new biotechnical field. This comprehensive and innovative bioremediation education program provides under-represented groups with a cross-disciplinary bioremediation cirruculum and financial support, coupled with relevant training experiences at advanced research laboratories and field sites. These programs are designed to provide a stream of highly trained minority and women professionals to meet national environmental needs.

In situ groundwater bioremediation

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

Hazen, Terry C.

2009-02-01

In situ groundwater bioremediation of hydrocarbons has been used for more than 40 years. Most strategies involve biostimulation; however, recently bioaugmentation have been used for dehalorespiration. Aquifer and contaminant profiles are critical to determining the feasibility and strategy for in situ groundwater bioremediation. Hydraulic conductivity and redox conditions, including concentrations of terminal electron acceptors are critical to determine the feasibility and strategy for potential bioremediation applications. Conceptual models followed by characterization and subsequent numerical models are critical for efficient and cost effective bioremediation. Critical research needs in this area include better modeling and integration of remediation strategies with natural attenuation.

Comparison of Natural and Engineered Chlorophenol Bioremediation Enzymes

DTIC Science & Technology

2015-02-26

herein addresses the urgent need to incorporate biological strategies into environmental restoration efforts ( bioremediation ) that focus on the catalytic... Bioremediation Enzymes The views, opinions and/or findings contained in this report are those of the author(s) and should not contrued as an official Department...Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 dehaloperoxidase, bioremediation , halophenol, Amphitrite ornata, marine

Aerobic Bioremediation of PAH Contaminated Soil Results in Increased Genotoxicity and Developmental Toxicity

PubMed Central

Chibwe, Leah; Geier, Mitra C.; Nakamura, Jun; Tanguay, Robert L.; Aitken, Michael D.; Simonich, Staci L. Massey

2015-01-01

The formation of more polar and toxic polycyclic aromatic hydrocarbon (PAH) transformation products is one of the concerns associated with the bioremediation of PAH-contaminated soils. Soil contaminated with coal tar (pre-bioremediation) from a former manufactured gas plant (MGP) site was treated in a laboratory scale bioreactor (post-bioremediation) and extracted using pressurized liquid extraction. The soil extracts were fractionated, based on polarity, and analyzed for 88 PAHs (unsubstituted, oxygenated, nitrated, and heterocyclic PAHs). The PAH concentrations in the soil tested, post-bioremediation, were lower than their regulatory maximum allowable concentrations (MACs), with the exception of the higher molecular weight PAHs (BaA, BkF, BbF, BaP, and IcdP), most of which did not undergo significant biodegradation. The soil extract fractions were tested for genotoxicity using the DT40 chicken lymphocyte bioassay and developmental to xicity using the embryonic zebrafish (Danio rerio) bioassay. A statistically significant increase in genotoxicity was measured in the unfractionated soil extract, as well as in four polar soil extract fractions, post-bioremediation (p < 0.05). In addition, a statistically significant increase in developmental toxicity was measured in one polar soil extract fraction, post-bioremediation (p < 0.05). A series of morphological abnormalities, including peculiar caudal fin malformations and hyperpigmentation in the tail, were measured in several soil extract fractions in embryonic zebrafish, both pre- and post-bioremediation. The increased toxicity measured post-bioremediation is not likely due to the 88 PAHs measured in this study (including quinones), because most were not present in the toxic polar fractions and/or because their concentrations did not increase post-bioremediation. However, the increased toxicity measured post-bioremediation is likely due to hydroxylated and carboxylated transformation products of the 3- and 4-ring PAHs (PHE, 1MPHE, 2MPHE, PRY, BaA, and FLA) that were most degraded. PMID:26200254

Some Case Studies on Metal-Microbe Interactions to Remediate Heavy Metals- Contaminated Soils in Korea

NASA Astrophysics Data System (ADS)

Chon, Hyo-Taek

2015-04-01

Conventional physicochemical technologies to remediate heavy metals-contaminated soil have many problems such as low efficiency, high cost and occurrence of byproducts. Recently bioremediation technology is getting more and more attention. Bioremediation is defined as the use of biological methods to remediate and/or restore the contaminated land. The objectives of bioremediation are to degrade hazardous organic contaminants and to convert hazardous inorganic contaminants to less toxic compounds of safe levels. The use of bioremediation in the treatment of heavy metals in soils is a relatively new concept. Bioremediation using microbes has been developed to remove toxic heavy metals from contaminated soils in laboratory scale to the contaminated field sites. Recently the application of cost-effective and environment-friendly bioremediation technology to the heavy metals-contaminated sites has been gradually realized in Korea. The merits of bioremediation include low cost, natural process, minimal exposure to the contaminants, and minimum amount of equipment. The limitations of bioremediation are length of remediation, long monitoring time, and, sometimes, toxicity of byproducts for especially organic contaminants. From now on, it is necessary to prove applicability of the technologies to contaminated sites and to establish highly effective, low-cost and easy bioremediation technology. Four categories of metal-microbe interactions are generally biosorption, bioreduction, biomineralization and bioleaching. In this paper, some case studies of the above metal-microbe interactions in author's lab which were published recently in domestic and international journals will be introduced and summarized.

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

PubMed

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

2018-04-01

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

The El Horror uranium anomaly in northeastern Sonora, Mexico: Constraints from geochemical and mineralogical approaches

NASA Astrophysics Data System (ADS)

Grijalva-Rodríguez, T.; Valencia-Moreno, M.; Calmus, T.; Del Rio-Salas, R.; Balcázar-García, M.

2017-12-01

This work reviews the characteristics of the El Horror uranium prospect in northeastern Sonora, Mexico. It was formerly detected by a radiometric anomaly after airborne gamma ray exploration carried out in the 70's by the Mexican government. As a promising site to contain important uranium resources, the El Horror was re-evaluated by CFE (Federal Electricity Commission) by in situ gamma ray surveys. The study also incorporates rock and stream sediment ICP-MS geochemistry, X-ray diffraction, X-ray fluorescence, Raman spectrometry and Scanning Electron Microscopy (SEM) to provide a better understanding of the radiometric anomaly. The results show that, instead of a single anomaly, it comprises at least five individual anomalies hosted in hydrothermally altered Laramide (80-40 Ma) andesitic volcanic rocks of the Tarahumara Formation. Concentrations for elemental uranium and uranium calculated from gamma ray surveys (i.e., equivalent uranium) are not spatially coincident within the anomaly, but, at least at some degree, they do so in specific sites. X-ray diffraction and Raman spectrometry revealed the presence of rutile/anatase, uvite, bukouvskyte and allanite as the more likely mineral phases to contain uranium. SEM studies revealed a process of iron-rich concretion formation, suggesting that uranium was initially incorporated to the system by adsorption, but was largely removed later during incorporation of Fe+3 ions. Stream sediment geochemistry reveals that the highest uranium concentrations are derived from the southern part of the Sierra La Madera batholith (∼63 Ma), and decrease toward the El Horror anomaly.

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

Denton, J. S.; Goldstein, S. J.; Paviet, P.

Studies of uranium-series (U-series) disequilibria within and around ore deposits provide valuable information on the extent and timing of actinide mobility, via mineral-fluid interaction, over a range of spatial and temporal scales. Such information is useful in studies of analogs of high-level nuclear-waste repositories, as well as for mining and mineral extraction sites, locations of previous nuclear weapons testing, and legacy nuclear waste contamination. In this study we present isotope dilution mass spectrometry U-series measurements for fracture-fill materials (hematite, goethite, kaolinite, calcite, dolomite and quartz) from one such analog; the Nopal I uranium ore deposit situated at Peña Blanca inmore » the Chihuahua region of northern Mexico. The ore deposit is located in fractured, unsaturated volcanic tuff and fracture-fill materials from surface fractures as well as fractures in a vertical drill core have been analyzed. High uranium concentrations in the fracture-fill materials (between 12 and 7700 ppm) indicate uranium mobility and transport from the deposit. Furthermore, uranium concentrations generally decrease with horizontal distance away from the deposit but in this deposit there is no trend with depth below the surface.« less

Bioavailable cadmium during the bioremediation of phenanthrene-contaminated soils using the diffusive gradients in thin-film technique.

PubMed

Amezcua-Allieri, M A; Rodríguez-Vázquez, R

2006-03-01

To study the impact of fungal bioremediation of phenanthrene on trace cadmium solid-solution fluxes and solution phase concentration. The bioremediation of phenanthrene in soils was performed using the fungus Penicillium frequentans. Metal behaviour was evaluated by the techniques of diffusive gradient in thin-films (DGT) and filtration. Fluxes of cadmium (Cd) show a significant (P < 0.002) increase after the start of bioremediation, indicating that the bioremediation process itself releases significant amount of Cd into solution from the soil solid-phase. Unlike DGT devices, the solution concentration from filtration shows a clear bimodal distribution. We postulate that the initial action of the fungi is most likely to breakdown the surface of the solid phase to smaller, 'solution-phase' material (<0.45 microm) leading to a peak in Cd concentration in solution. Phenanthrene removal from soils by bioremediation ironically results in the mobilization of another toxic pollutant (Cd). Bioremediation of organic pollutants in contaminated soil will likely lead to large increases in the mobilization of toxic metals, increasing metal bio-uptake and incorporation into the wider food chain. Bioremediation strategies need to account for this behaviour and further research is required both to understand the generality of this behaviour and the operative mechanisms.

High-resolution mineralogical characterization and biogeochemical modeling of uranium reaction pathways at the FRC

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

Chen Zhu

2006-06-15

High-Resolution Mineralogical Characterization and Biogeochemical Modeling of Uranium Reduction Pathways at the Oak Ridge Field-Research Center (FRC) Chen Zhu, Indiana University, David R. Veblen, Johns Hopkins University We have successfully completed a proof-of-concept, one-year grant on a three-year proposal from the former NABIR program, and here we seek additional two-year funding to complete and publish the research. Using a state-of-the-art 300-kV, atomic resolution, Field Emission Gun Transmission Electron Microscope (TEM), we have successfully identified three categories of mineral hosts for uranium in contaminated soils: (1) iron oxides; (2) mixed manganese-iron oxides; and (3) uranium phosphates. Method development using parallel electronmore » energy loss spectroscopy (EELS) associated with the TEM shows great promise for characterizing the valence states of immobilized U during bioremediation. We have also collected 27 groundwater samples from two push-pull field biostimulation tests, which form two time series from zero to approximately 600 hours. The temporal evolution in major cations, anions, trace elements, and the stable isotopes 34S, 18O in sulfate, 15N in nitrate, and 13C in dissolved inorganic carbon (DIC) clearly show that biostimulation resulted in reduction of nitrate, Mn(IV), Fe(III), U(VI), sulfate, and Tc(VII), and these reduction reactions were intimately coupled with a complex network of inorganic reactions evident from alkalinity, pH, Na, K, Mg, and Ca concentrations. From these temporal trends, apparent zero order rates were regressed. However, our extensive suite of chemical and isotopic data sets, perhaps the first and only comprehensive data set available at the FRC, show that the derived rates from these field biostimulation experiments are composite and lump-sum rates. There were several reactions that were occurring at the same time but were masked by these pseudo-zero order rates. A reaction-path model comprising a total of nine redox couples (NO3–/NH4+, MnO2(s)/Mn2+, Fe(OH)3(s) /Fe2+, TcO4–/TcO2(s), UO22+/UO2(s), SO42–/HS–, CO2/CH4, ethanol/acetate, and H+/H2.) is used to simulate the temporal biogeochemical evolution observed in the field tests. Preliminary results show that the models based on thermodynamics and more complex rate laws can generate the apparent zero order rates when several concurrent or competing reactions occur. Professor Alex Halliday of Oxford University, UK, and his postdoctoral associates are measuring the uranium isotopes in our groundwater samples. Newly developed state-of-the-art analytical techniques in measuring variability in 235U/238U offer the potential to distinguish biotic and abiotic uranium reductive mechanisms.« less

Uranium enrichment in lacustrine oil source rocks of the Chang 7 member of the Yanchang Formation, Erdos Basin, China

NASA Astrophysics Data System (ADS)

Yang, Hua; Zhang, Wenzheng; Wu, Kai; Li, Shanpeng; Peng, Ping'an; Qin, Yan

2010-09-01

The oil source rocks of the Chang 7 member of the Yanchang Formation in the Erdos Basin were deposited during maximum lake extension during the Late Triassic and show a remarkable positive uranium anomaly, with an average uranium content as high as 51.1 μg/g. Uranium is enriched together with organic matter and elements such as Fe, S, Cu, V and Mo in the rocks. The detailed biological markers determined in the Chang 7 member indicate that the lake water column was oxidizing during deposition of the Chang 7 member. However, redox indicators for sediments such as S 2- content, V/Sc and V/(V + Ni) ratios demonstrate that it was a typical anoxic diagenetic setting. The contrasted redox conditions between the water column and the sediment with a very high content of organic matter provided favorable physical and chemical conditions for syngenetic uranium enrichment in the oil source rocks of the Chang 7 member. Possible uranium sources may be the extensive U-rich volcanic ash that resulted from contemporaneous volcanic eruption and uranium material transported by hydrothermal conduits into the basin. The uranium from terrestrial clastics was unlike because uranium concentration was not higher in the margin area of basin where the terrestrial material input was high. As indicated by correlative analysis, the oil source rocks of the Chang 7 member show high gamma-ray values for radioactive well log data that reflect a positive uranium anomaly and are characterized by high resistance, low electric potential and low density. As a result, well log data can be used to identify positive uranium anomalies and spatial distribution of the oil source rocks in the Erdos Basin. The estimation of the total uranium reserves in the Chang 7 member attain 0.8 × 10 8 t.

Reductive dechlorination of trichloroethene DNAPL source zones: source zone architecture versus electron donor availability

NASA Astrophysics Data System (ADS)

Krol, M.; Kokkinaki, A.; Sleep, B.

2014-12-01

The persistence of dense-non-aqueous-phase liquids (DNAPLs) in the subsurface has led practitioners and regulatory agencies to turn towards low-maintenance, low-cost remediation methods. Biological degradation has been suggested as a possible solution, based on the well-proven ability of certain microbial species to break down dissolved chlorinated ethenes under favorable conditions. However, the biodegradation of pure phase chlorinated ethenes is subject to additional constraints: the continuous release of electron acceptor at a rate governed by mass transfer kinetics, and the temporal and spatial heterogeneity of DNAPL source zones which leads to spatially and temporally variable availability of the reactants for reductive dechlorination. In this work, we investigate the relationship between various DNAPL source zone characteristics and reaction kinetics using COMPSIM, a multiphase groundwater model that considers non-equilibrium mass transfer and Monod-type kinetics for reductive dechlorination. Numerical simulations are performed for simple, homogeneous trichloroethene DNAPL source zones to demonstrate the effect of single source zone characteristics, as well as for larger, more realistic heterogeneous source zones. It is shown that source zone size, and mass transfer kinetics may have a decisive effect on the predicted bio-enhancement. Finally, we evaluate the performance of DNAPL bioremediation for realistic, thermodynamically constrained, concentrations of electron donor. Our results indicate that the latter may be the most important limitation for the success of DNAPL bioremediation, leading to reduced bio-enhancement and, in many cases, comparable performance with water flooding.

Hydrocarbon-mediated gold and uranium concentration in the Witwatersrand Basin, South Africa

NASA Astrophysics Data System (ADS)

Fuchs, Sebastian; Williams-Jones, Anthony; Schumann, Dirk; Couillard, Martin; Murray, Andrew

2016-04-01

The Witwatersrand deposits in South Africa represent the largest repository of gold in the World and a major resource of uranium. The genesis of the gold and uranium ores in the quartz-pebble conglomerates (reefs), however, is still a matter of considerable discussion. Opinion has been divided over whether they represent paleo-placers that have been partly remobilised by hydrothermal fluids or if the mineralisation is entirely hydrothermal in origin. In addition, recently published models have proposed a syngenetic origin for the gold involving bacterially-mediated precipitation from meteoric water and shallow seawater. An important feature of the gold and uranium mineralisation in the reefs is the strong spatial association with organic matter. In some reefs, up to 70% of the gold and almost the entire uranium resource is spatially associated with pyrobitumen seams, suggesting a genetic relationship of the gold-uranium mineralisation with hydrocarbons. Here we report results of a study of the Carbon Leader Reef, using high-resolution scanning and transmission electron microscopy (SEM / TEM) and LA-ICP-MS that provide new insights into the role of hydrocarbons in the concentration of the gold and uranium. A detailed examination revealed gold monocrystals containing numerous rounded or elliptical inclusions filled with pyrobitumen. We interpret these inclusions to record the crystallisation of the gold around droplets of a hydrocarbon liquid that migrated through the Witwatersrand basin, and was converted to pyrobitumen by being heated. We propose that the gold was transported in a hydrothermal fluid as a bisulphide complex and that this fluid mixed with the hydrocarbon liquid to form a water-oil emulsion. The interaction between the two fluids caused a sharp reduction in fO2 at the water-oil interface, which destabilised the gold-bisulphide complexes, causing gold monocrystals to precipitate around the oil droplets. In contrast to the gold, uraninite, the principal uranium mineral, occurs as complex-shaped grains that represent aggregates containing billions of uraninite nanocrystals (5 - 7 nm in diameter), which grew in situ in the pyrobitumen matrix or more likely its liquid precursor (Fuchs et al., 2015). This in situ growth of isolated nanocrystalline aggregates shows that uranium was mobilised and concentrated by liquid hydrocarbons, and that uraninite nanocrystals were released from the oils during the conversion of oil to pyrobitumen. Our study provides new insights into the complex mechanisms of ore formation in the Witwatersrand Supergroup and compelling evidence that hydrocarbons played a major role in the concentration of the gold and uranium. It does not rule out the possibility that gold and uranium were introduced into the Witwatersrand Basin as detrital grains but shows that mobilisation of gold and uranium by hydrothermal fluids and hydrocarbon liquids, respectively, and the mixing of these fluids, were essential to ore formation. Fuchs, S., Schumann, D., Williams-Jones, A.E., Vali, H., 2015. The growth and concentration of uranium and titanium minerals in hydrocarbons of the Carbon Leader Reef, Witwatersrand Supergroup, South Africa. Chemical Geology 393-394, 55-66.

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

Mouser, Paula J.; N'Guessan, A. Lucie; Qafoku, Nikolla

The capacity for subsurface sediments to sequester metal contaminants, such as uranium (U), and retain them after bioremediation efforts are completed is critical to site stewardship. Sediments enriched in natural organic matter are capable of sequestering significant quantities of U, but may also serve as sources to the aquifer, contributing to plume persistence. Two types of sediments were compared to better understand the mechanisms contributing to the sequestration and release of U in the presence of organic matter. Artificially bioreduced sediments were retrieved from a field experimental plot previously stimulated with acetate while naturally bioreduced sediments were collected from amore » location enriched in organic matter but never subject to acetate amendment. Batch incubations demonstrated that the artificially bioreduced sediments were primed to rapidly remove uranium from the groundwater whereas naturally bioreduced sediments initially released a sizeable portion of sediment U before U(VI)-removal commenced. Column experiments confirmed that U release persisted for 65 pore volumes in naturally bioreduced sediments, demonstrating the sink-source behavior of this sediment. Acetate addition to artificially bioreduced sediments shifted the microbial community from one dominated by sulfate-reducing bacteria within Desulfobacteraceae to the iron-reducing family Geobacteraceae and Firmicutes during U(VI) reduction. In contrast, initial Geobacteraceae communities innaturally reduced sediments were replaced by clone sequences with similarity to opportunistic Pseudomonas spp. during U release, while U(VI) removal occurred concurrent with enrichment of Firmicutes. These investigations stress the importance of characterizing zones with heterogeneous carbon pools at U contaminated sites prior to the determination of a remedial strategy.« less

A field experiment and numerical modeling of a tracer at a gravel beach in Prince William Sound, Alaska

NASA Astrophysics Data System (ADS)

Guo, Qiaona; Li, Hailong; Boufadel, Michel C.; Liu, Jin

2014-12-01

Oil from the 1989 Exxon Valdez oil spill persists in many gravel beaches in Prince William Sound (Alaska, USA), despite great remedial efforts. A tracer study using lithium at a gravel beach on Knight Island, Prince William Sound, during the summer of 2008 is reported. The tracer injection and transport along a transect were simulated using the two-dimensional numerical model MARUN. Model results successfully reproduced the tracer concentrations observed at wells along the transect. A sensitivity analysis revealed that the estimated parameters are well determined. The simulated spatial distribution of tracer indicated that nutrients applied along the transect for bioremediation purposes would be washed to the sea very quickly (within a semi-diurnal tidal cycle) by virtue of the combination of the two-layered beach structure, the tidal fluctuation and the freshwater flow from inland. Thus, pore-water samples in the transect were found to be clean due to factors other than bioremediation. This may explain why the oil did not persist within the transect.

GRACE BIOREMEDIATION TECHNOLOGIES - DARAMEND™ BIOREMEDIATION TECHNOLOGY. INNOVATIVE TECHNOLOGY EVALUATION REPORT

EPA Science Inventory

Grace Dearborn's DARAMEND™ Bioremediation Technology was developed to treat soils/sediment contaminated with organic contaminants using solid-phase organic amendments. The amendments increase the soil’s ability to supply biologically available water/nutrients to micro...

Guidelines for the Bioremediation of Oil-Contaminated Salt Marshes

EPA Pesticide Factsheets

This document includes a review and critique of the literature and theories pertinent to oil biodegradation and nutrient dynamics and provides examples of bioremediation options and case studies of oil bioremediation in coastal wetland environments.

Development and Validation of a Quantitative Framework and Management Expectation Tool for the Selection of Bioremediation Approaches at Chlorinated Ethene Sites

DTIC Science & Technology

2015-12-01

FINAL REPORT Development and Validation of a Quantitative Framework and Management Expectation Tool for the Selection of Bioremediation ...TITLE AND SUBTITLE Development and Validation of a Quantitative Framework and Management Expectation Tool for the Selection of Bioremediation ...project ER-201129 was to develop and validate a framework used to make bioremediation decisions based on site-specific physical and biogeochemical

Treatment of petroleum hydrocarbon polluted environment through bioremediation: a review.

PubMed

Singh, Kriti; Chandra, Subhash

2014-01-01

Bioremediation play key role in the treatment of petroleum hydrocarbon contaminated environment. Exposure of petroleum hydrocarbon into the environment occurs either due to human activities or accidentally and cause environmental pollution. Petroleum hydrocarbon cause many toxic compounds which are potent immunotoxicants and carcinogenic to human being. Remedial methods for the treatment of petroleum contaminated environment include various physiochemical and biological methods. Due to the negative consequences caused by the physiochemical methods, the bioremediation technology is widely adapted and considered as one of the best technology for the treatment of petroleum contaminated environment. Bioremediation utilizes the natural ability of microorganism to degrade the hazardous compound into simpler and non hazardous form. This paper provides a review on the role of bioremediation in the treatment of petroleum contaminated environment, discuss various hazardous effects of petroleum hydrocarbon, various factors influencing biodegradation, role of various enzymes in biodegradation and genetic engineering in bioremediation.

Spatially-Resolved Analyses of Aerodynamic Fallout from a Uranium-Fueled Nuclear Test

DOE PAGES

Lewis, L. A.; Knight, K. B.; Matzel, J. E.; ...

2015-07-28

The fiive silicate fallout glass spherules produced in a uranium-fueled, near-surface nuclear test were characterized by secondary ion mass spectrometry, electron probe microanalysis, autoradiography, scanning electron microscopy, and energy-dispersive x-ray spectroscopy. Several samples display compositional heterogeneity suggestive of incomplete mixing between major elements and natural U ( 238U/ 235U = 0.00725) and enriched U. Samples exhibit extreme spatial heterogeneity in U isotopic composition with 0.02 < 235U/ 238U < 11.84 among all five spherules and 0.02 < 235U/ 238U < 7.41 within a single spherule. Moreover, in two spherules, the 235U/ 238U ratio is correlated with changes in major elementmore » composition, suggesting the agglomeration of chemically and isotopically distinct molten precursors. Two samples are nearly homogenous with respect to major element and uranium isotopic composition, suggesting extensive mixing possibly due to experiencing higher temperatures or residing longer in the fireball. Linear correlations between 234U/ 238U, 235U/ 238U, and 236U/ 238U ratios are consistent with a two-component mixing model, which is used to illustrate the extent of mixing between natural and enriched U end members.« less

The use of bacterial bioremediation of metals in aquatic environments in the twenty-first century: a systematic review.

PubMed

de Alencar, Feliphe Lacerda Souza; Navoni, Julio Alejandro; do Amaral, Viviane Souza

2017-07-01

Metal pollution is a current environmental issue as a consequence of unregulated anthropic activiy. A wide range of bioremediation strategies have been successfully implemented to recover contaminated areas. Among them, bacterial bioremediation stands out as a promising tool to confront these types of concerns. This study aimed to compare and discuss worldwide scientific evolution of bacterial potential for metal bioremediation in aquatic ecosystems. The study consisted of a systematic review, elaborated through a conceptual hypothesis model, during the period from 2000 to 2016, using PubMed, MEDLINE, and SciELO databases as data resources. The countries with the largest number of reports included in this work were India and the USA. Industrial wastewater discharge was the main subject associated to metal contamination/pollution and where bacterial bioremediations have mostly been applied. Biosorption is the main bioremediation mechanism described. Bacterial adaptation to metal presence was discussed in all the selected studies, and chromium was the most researched bioremedied substrate. Gram-negative Pseudomonas aeruginosas and the Gram-positive Bacillus subtilis bacteria were microorganisms with the greatest applicability for metal bioremediation. Most reports involved the study of genes and/or proteins related to metal metabolism and/or resistence, and Chromobacterium violaceum was the most studied. The present work shows the relevance of metal bacterial bioremediation through the high number of studies aimed at understanding the microbiological mechanisms involved. Moreover, the developed processes applied in removal and/or reducing the resulting environmental metal contaminant/pollutant load have become a current and increasingly biotechnological issue for recovering impacted areas.

BIOREMEDIATION OF OIL-CONTAMINATED FINE SEDIMENTS.

EPA Science Inventory

Bioremediation of oil contamination has been shown to be effective for cobble and sandy shorelines. To assess the operational limitations of this technology, this project studied its potential to treat buried oil in fine sediments. The effectiveness of bioremediation by nutrient ...

Bioremediation of oil-contaminated soils: A recipe for success

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

Wittenbach, S.A.

1995-12-31

Bioremediation of land crude oil and lube oil spills is an effective and economical option. Other options include road spreading (where permitted), thermal desorption, and off-site disposal. The challenge for environment and operations managers is to select the best approach for each remediation site. Costs and liability for off-site disposal are ever increasing. Kerr-McGee`s extensive field research in eastern and western Texas provides the data to support bioremediation as a legitimate and valid option. Both practical and economical bioremediation as a legitimate and valid option. Both practical and economical, bioremediation also offers a lower risk of, for example, Superfund clean-upmore » exposure than off-site disposal.« less

Microbial communities biostimulated by ethanol during uranium (VI) bioremediation in contaminated sediment as shown by stable isotope probing

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

Leigh, Mary Beth; Wu, Wei -Min; Cardenas, Erick

Stable isotope probing (SIP) was used to identify microbes stimulated by ethanol addition in microcosms containing two sediments collected from the bioremediation test zone at the US Department of Energy Oak Ridge site, TN, USA. One sample was highly bioreduced with ethanol while another was less reduced. Microcosms with the respective sediments were amended with 13C labeled ethanol and incubated for 7 days for SIP. Ethanol was rapidly converted to acetate within 24 h accompanied with the reduction of nitrate and sulfate. The accumulation of acetate persisted beyond the 7 d period. Aqueous U did not decline in the microcosmmore » with the reduced sediment due to desorption of U but continuously declined in the less reduced sample. Microbial growth and concomitant 13C-DNA production was detected when ethanol was exhausted and abundant acetate had accumulated in both microcosms. This coincided with U(VI) reduction in the less reduced sample. 13C originating from ethanol was ultimately utilized for growth, either directly or indirectly, by the dominant microbial community members within 7 days of incubation. The microbial community was comprised predominantly of known denitrifiers, sulfate-reducing bacteria and iron (III) reducing bacteria including Desulfovibrio, Sphingomonas, Ferribacterium, Rhodanobacter, Geothrix, Thiobacillus and others, including the known U(VI)-reducing bacteria Acidovorax, Anaeromyxobacter, Desulfovibrio, Geobacter and Desulfosporosinus. As a result, the findings suggest that ethanol biostimulates the U(VI)-reducing microbial community by first serving as an electron donor for nitrate, sulfate, iron (III) and U(VI) reduction, and acetate which then functions as electron donor for U(VI) reduction and carbon source for microbial growth.« less

4D ERT-based calibration and prediction of biostimulant induced changes in fluid conductivity

NASA Astrophysics Data System (ADS)

Johnson, T. C.; Versteeg, R. J.; Day-Lewis, F. D.; Major, W. R.; Wright, K. E.

2008-12-01

In-situ bioremediation is an emerging and cost-effective method of removing organic contaminants from groundwater. The performance of bioremedial systems depends on the adequate delivery and distribution of biostimulants to contaminated zones. Monitoring the distribution of biostimulants using monitoring wells is expensive, time consuming, and provides inadequate information between sampling wells. We discuss a Hydrogeophysical Performance Monitoring System (HPMS) deployed to monitor bioremediation efforts at a TCE-contaminated Superfund site in Brandywine MD. The HPMS enables autonomous electrical geophysical data acquisition, processing, quality-assurance/quality-control, and inversion. Our objective is to demonstrate the feasibility and cost effectiveness of the HPMS to provide near real-time information on the spatiotemporal behavior of injected biostimulants. As a first step, we use time-lapse electrical resistivity tomography (ERT) to estimate changes in bulk conductivity caused by the injectate. We demonstrate how ERT-based bulk conductivity estimates can be calibrated with a small number of fluid conductivity measurements to produce ERT-based estimates of fluid conductivity. The calibration procedure addresses the spatially variable resolution of the ERT tomograms. To test the validity of these estimates, we used the ERT results to predict the fluid conductivity at tens of points prior to field sampling of fluid conductivity at the same points. The comparison of ERT-predicted vs. observed fluid conductivity displays a high degree of correlation (correlation coefficient over 0.8), and demonstrates the ability of the HPMS to estimate the four-dimensional (4D) distribution of fluid conductivity caused by the biostimulant injection.

Spatial Distribution of an Uranium-Respiring Betaproteobacterium at the Rifle, CO Field Research Site

PubMed Central

Koribanics, Nicole M.; Tuorto, Steven J.; Lopez-Chiaffarelli, Nora; McGuinness, Lora R.; Häggblom, Max M.; Williams, Kenneth H.; Long, Philip E.; Kerkhof, Lee J.

2015-01-01

The Department of Energy’s Integrated Field-Scale Subsurface Research Challenge Site (IFRC) at Rifle, Colorado was created to address the gaps in knowledge on the mechanisms and rates of U(VI) bioreduction in alluvial sediments. Previous studies at the Rifle IFRC have linked microbial processes to uranium immobilization during acetate amendment. Several key bacteria believed to be involved in radionuclide containment have been described; however, most of the evidence implicating uranium reduction with specific microbiota has been indirect. Here, we report on the cultivation of a microorganism from the Rifle IFRC that reduces uranium and appears to utilize it as a terminal electron acceptor for respiration with acetate as electron donor. Furthermore, this bacterium constitutes a significant proportion of the subsurface sediment community prior to biostimulation based on TRFLP profiling of 16S rRNA genes. 16S rRNA gene sequence analysis indicates that the microorganism is a betaproteobacterium with a high similarity to Burkholderia fungorum. This is, to our knowledge, the first report of a betaproteobacterium capable of uranium respiration. Our results indicate that this microorganism occurs commonly in alluvial sediments located between 3-6 m below ground surface at Rifle and may play a role in the initial reduction of uranium at the site. PMID:25874721

Spatial distribution of an uranium-respiring betaproteobacterium at the Rifle, CO field research site

DOE PAGES

Koribanics, Nicole M.; Tuorto, Steven J.; Lopez-Chiaffarelli, Nora; ...

2015-04-13

The Department of Energy’s Integrated Field-Scale Subsurface Research Challenge Site (IFRC) at Rifle, Colorado was created to address the gaps in knowledge on the mechanisms and rates of U(VI) bioreduction in alluvial sediments. Previous studies at the Rifle IFRC have linked microbial processes to uranium immobilization during acetate amendment. Several key bacteria believed to be involved in radionuclide containment have been described; however, most of the evidence implicating uranium reduction with specific microbiota has been indirect. Here, we report on the cultivation of a microorganism from the Rifle IFRC that reduces uranium and appears to utilize it as a terminalmore » electron acceptor for respiration with acetate as electron donor. Furthermore, this bacterium constitutes a significant proportion of the subsurface sediment community prior to biostimulation based on TRFLP profiling of 16S rRNA genes. 16S rRNA gene sequence analysis indicates that the microorganism is a betaproteobacterium with a high similarity to Burkholderia fungorum. This is, to our knowledge, the first report of a betaproteobacterium capable of uranium respiration. Our results indicate that this microorganism occurs commonly in alluvial sediments located between 3-6 m below ground surface at Rifle and may play a role in the initial reduction of uranium at the site.« less

Ecotoxicological assessment of oil-based paint using three-dimensional multi-species bio-testing model: pre- and post-bioremediation analysis.

PubMed

Phulpoto, Anwar Hussain; Qazi, Muneer Ahmed; Haq, Ihsan Ul; Phul, Abdul Rahman; Ahmed, Safia; Kanhar, Nisar Ahmed

2018-06-01

The present study validates the oil-based paint bioremediation potential of Bacillus subtilis NAP1 for ecotoxicological assessment using a three-dimensional multi-species bio-testing model. The model included bioassays to determine phytotoxic effect, cytotoxic effect, and antimicrobial effect of oil-based paint. Additionally, the antioxidant activity of pre- and post-bioremediation samples was also detected to confirm its detoxification. Although, the pre-bioremediation samples of oil-based paint displayed significant toxicity against all the life forms. However, post-bioremediation, the cytotoxic effect against Artemia salina revealed substantial detoxification of oil-based paint with LD 50 of 121 μl ml -1 (without glucose) and > 400 μl ml -1 (with glucose). Similarly, the reduction in toxicity against Raphanus raphanistrum seeds germination (%FG = 98 to 100%) was also evident of successful detoxification under experimental conditions. Moreover, the toxicity against test bacterial strains and fungal strains was completely removed after bioremediation. In addition, the post-bioremediation samples showed reduced antioxidant activities (% scavenging = 23.5 ± 0.35 and 28.9 ± 2.7) without and with glucose, respectively. Convincingly, the present multi-species bio-testing model in addition to antioxidant studies could be suggested as a validation tool for bioremediation experiments, especially for middle and low-income countries. Graphical abstract ᅟ.

Ex situ bioremediation of oil-contaminated soil.

PubMed

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

2010-04-15

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

Healthy environments for healthy people: bioremediation today and tomorrow.

PubMed Central

Bonaventura, C; Johnson, F M

1997-01-01

Increases in environmental contamination lead to a progressive deterioration of environmental quality. This condition challenges our global society to find effective measures of remediation to reverse the negative conditions that severely threaten human and environmental health. We discuss the progress being made toward this goal through application of bioremediation techniques. Bioremediation generally utilizes microbes (bacteria, fungi, yeast, and algae), although higher plants are used in some applications. New bioremediation approaches are emerging based on advances in molecular biology and process engineering. Bioremediation continues to be the favored approach for processing biological wastes and avoiding microbial pathogenesis. Bioremediation may also play an increasing role in concentrating metals and radioactive materials to avoid toxicity or to recover metals for reuse. Microbes can biodegrade organic chemicals; purposeful enhancement of this natural process can aid in pollutant degradation and waste-site cleanup operations. Recently developed rapid-screening assays can identify organisms capable of degrading specific wastes and new gene-probe methods can ascertain their abundance at specific sites. New tools and techniques for use of bioremediation in situ, in biofilters, and in bioreactors are contributing to the rapid growth of this field. Bioremediation has already proven itself to be a cost-effective and beneficial addition to chemical and physical methods of managing wastes and environmental pollutants. We anticipate that it will play an increasingly important role as a result of new and emerging techniques and processes. Images Figure 3. PMID:9114274

Bioremediation of treated wood with bacteria

Treesearch

Carol A. Clausen

2006-01-01

This chapter reviews prior research in the field of bacterial bioremediation for wood treated with oilborne and inorganic preservatives. Current state of the art is summarized along with potential benefits and pitfalls of a pilot-scale bioremediation process for CCA-treated waste wood.

MUTAGENICITY OF PAH-CONTAMINATED SOILS DURING BIOREMEDIATION

EPA Science Inventory

Bioremediation of contaminated soils is considered an effective method for reducing potential health hazards. Although it is assumed that (bio)remediation is a detoxifying process, degradation products of compounds such as polycyclic aromatic compounds (PACs) can be more toxic th...

BIOREMEDIATION OF PETROLEUM HYDROCARBON CONTAMINANTS IN MARINE HABITATS

EPA Science Inventory

Bioremediation is being increasingly seen as an effective environmentally benign treatment for shorelines contaminated as a result of marine oil spills. Despite a relatively long history of research on oil-spill bioremediation, it remains an essentially empirical technology and m...

BIOREMEDIATION FIELD EVALUATION - HILL AIR FORCE BASE, UTAH

EPA Science Inventory

In 1990, the U.S. Environmental Protection Agency (EPA) established the Bioremediation Field Initiative as part of its overall strategy to increase the use of bioremediation to treat hazardous wastes at Comprehensive Environmental Response, Compensation, and Liabil- ity Act (C...

40 CFR 300.910 - Authorization of use.

Code of Federal Regulations, 2012 CFR

2012-07-01

... dispersants, surface washing agents, surface collecting agents, bioremediation agents, or miscellaneous oil... agents, surface collecting agents, bioremediation agents, or miscellaneous oil spill control agents on..., bioremediation agent, or miscellaneous oil spill control agent, including products not listed on the NCP Product...

40 CFR 300.910 - Authorization of use.

Code of Federal Regulations, 2013 CFR

2013-07-01

... dispersants, surface washing agents, surface collecting agents, bioremediation agents, or miscellaneous oil... agents, surface collecting agents, bioremediation agents, or miscellaneous oil spill control agents on..., bioremediation agent, or miscellaneous oil spill control agent, including products not listed on the NCP Product...

40 CFR 300.910 - Authorization of use.

Code of Federal Regulations, 2014 CFR

2014-07-01

... dispersants, surface washing agents, surface collecting agents, bioremediation agents, or miscellaneous oil... agents, surface collecting agents, bioremediation agents, or miscellaneous oil spill control agents on..., bioremediation agent, or miscellaneous oil spill control agent, including products not listed on the NCP Product...

BENCH-SCALE PERFORMANCE OF PARTITIONING ELECTRON DONORS FOR TCE DNAPL BIOREMEDIATION

EPA Science Inventory

The objective of the Source Area Bioremediation (SABRE) project, an international collaboration of twelve companies, two government agencies and three research institutions, is to evaluate the performance of enhanced anaerobic bioremediation for the treatment of chlorinated ethen...

40 CFR 300.910 - Authorization of use.

Code of Federal Regulations, 2010 CFR

2010-07-01

... dispersants, surface washing agents, surface collecting agents, bioremediation agents, or miscellaneous oil... agents, surface collecting agents, bioremediation agents, or miscellaneous oil spill control agents on..., bioremediation agent, or miscellaneous oil spill control agent, including products not listed on the NCP Product...

78 FR 22256 - Proposed Information Collection Request; Comment Request; The National Oil and Hazardous...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-15

... Chemicals''). The use of bioremediation agents, dispersants, surface washing agents, surface collecting... basic categories: dispersants, surface washing agents, surface collecting agents, bioremediation agents..., manufacturers of bioremediation agents, dispersants, surface collecting agents, surface washing agents...

Changes in microbial populations and enzyme activities during the bioremediation of oil-contaminated soil.

PubMed

Lin, Xin; Li, Xiaojun; Sun, Tieheng; Li, Peijun; Zhou, Qixing; Sun, Lina; Hu, Xiaojun

2009-10-01

In the process of bioremediation in the soil contaminated by different oil concentrations, the changes in the microbial numbers (bacteria and fungi) and the enzyme (catalase (CAT), polyphenol oxidase (PPO) and lipase) activities were evaluated over a 2-year period. The results showed that the microbial numbers after 2-year bioremediation were one to ten times higher than those in the initial. The changes in the bacterial and the fungal populations were different during the bioremediation, and the highest microbial numbers for bacteria and fungi were 5.51 x 10(9) CFU g(-1) dry soil in treatment 3 (10,000 mg kg(-1)) in the initial and 5.54 x 10(5) CFU g(-1) dry soil in treatment 5 (50,000 mg kg(-1)) after the 2-year bioremediation period, respectively. The CAT and PPO activities in the contaminated soil decreased with increasing oil concentration, while the lipase activity increased. The activities of CAT and PPO improved after the bioremediation, but lipase activity was on the contrary. The CAT activity was more sensible to the oil than others, and could be alternative to monitor the bioremediation process.

Extracellular proteins limit the dispersal of biogenic nanoparticles

USGS Publications Warehouse

Moreau, J.W.; Weber, P.K.; Martin, M.C.; Gilbert, B.; Hutcheon, I.D.; Banfield, J.F.

2007-01-01

High-spatial-resolution secondary ion microprobe spectrometry, synchrotron radiation-based Fourier-transform infrared spectroscopy, and polyacrylamide gel analysis demonstrated the intimate association of proteins with spheroidal aggregates of biogenic zinc sulfide nanocrystals, an example of extracellular biomineralization. Experiments involving synthetic zinc sulfide nanoparticles and representative amino acids indicated a driving role for cysteine in rapid nanoparticle aggregation. These findings suggest that microbially derived extracellular proteins can limit the dispersal of nanoparticulate metal-bearing phases, such as the mineral products of bioremediation, that may otherwise be transported away from their source by subsurface fluid flow.

Design Of Bioremediation Systems For Groundwater (Aerobic and Anaerobic Plus Representative Case Studies)

EPA Science Inventory

The attached presentation discusses the fundamentals of bioremediation in the subsurface. The basics of aerobic, cometabolic, and anaerobic bioremediation are presented. Case studies from the Delaware Sand & Gravel Superfund Site, Dover Cometabolic Research Project and the SABR...

BIOREMEDIATION OF AN EXPERIMENTAL OIL SPILL ON THE SHORELINE OF DELAWARE BAY

EPA Science Inventory

In the summer of 1994, a field study was undertaken in Delaware in which light crude oil was intentionally released onto plots to evaluate bioremediation. The objectives were to obtain credible statistical evidence to determine if bioremediation with inorganic mineral nutrients ...

Development of Biomarkers for Assessing In Situ RDX Biodegradation Potential

DTIC Science & Technology

2016-06-10

bioremediation .................................................................................................................................. 4 2.1...RDX Degrading Microbial Communities and the Prediction of Microorganisms Responsible for RDX Bioremediation This review chapter was published...Cupples 2013), as follows: Cupples AM. 2013. RDX degrading microbial communities and the prediction of microorganisms responsible for RDX bioremediation

Cometabolic bioremediation

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

Hazen, Terry C.

2009-02-15

Cometabolic bioremediation is probably the most under appreciated bioremediation strategy currently available. Cometabolism strategies stimulate only indigenous microbes with the ability to degrade the contaminant and cosubstrate e.g. methane, propane, toluene and others. This highly targeted stimulation insures that only those microbes that can degrade the contaminant are targeted, thus reducing amendment costs, well and formation plugging, etc. Cometabolic bioremediation has been used on some of the most recalcitrant contaminants, e.g. PCE, TCE, MTBE, TNT, dioxane, atrazine, etc. Methanotrophs have been demonstrated to produce methane monooxygense, an oxidase that can degrade over 300 compounds. Cometabolic bioremediation also has the advantagemore » of being able to degrade contaminants to trace concentrations, since the biodegrader is not dependent on the contaminant for carbon or energy. Increasingly we are finding that in order to protect human health and the environment that we must remediate to lower and lower concentrations, especially for compounds like endocrine disrupters, thus cometabolism may be the best and maybe the only possibility that we have to bioremediate some contaminants.« less

Enhanced bioremediation of lead-contaminated soil by Solanum nigrum L. with Mucor circinelloides.

PubMed

Sun, Liqun; Cao, Xiufeng; Li, Min; Zhang, Xu; Li, Xinxin; Cui, Zhaojie

2017-04-01

Strain selected from mine tailings in Anshan for Pb bioremediation was characterized at the genetic level by internal transcribed spacer (ITS) sequencing. Results revealed that the strain belongs to Mucor circinelloides. Bioremediation of lead-contaminated soil was conducted using Solanum nigrum L. combined with M. circinelloides. The removal efficacy was in the order microbial/phytoremediation > phytoremediation > microbial remediation > control. The bioremediation rates were 58.6, 47.2, and 40.2% in microbial/phytoremediation, microbial remediation, and phytoremediation groups, respectively. Inoculating soil with M. circinelloides enhanced Pb removal and S. nigrum L. growth. The bioaccumulation factor (BF, 1.43), enrichment factor (EF, 1.56), and translocation factor (TF, 1.35) were higher than unit, suggesting an efficient ability of S. nigrum L. in Pb bioremediation. Soil fertility was increased after bioremediation according to change in enzyme activities. The results indicated that inoculating S. nigrum L. with M. circinelloides enhanced its efficiency for phytoremediation of soil contaminated with Pb.

Bioremediation of PAHs and VOCs: Advances in clay mineral-microbial interaction.

PubMed

Biswas, Bhabananda; Sarkar, Binoy; Rusmin, Ruhaida; Naidu, Ravi

2015-12-01

Bioremediation is an effective strategy for cleaning up organic contaminants, such as polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs). Advanced bioremediation implies that biotic agents are more efficient in degrading the contaminants completely. Bioremediation by microbial degradation is often employed and to make this process efficient, natural and cost-effective materials can serve as supportive matrices. Clay/modified clay minerals are effective adsorbents of PAHs/VOCs, and readily available substrate and habitat for microorganisms in the natural soil and sediment. However, the mechanism underpinning clay-mediated biodegradation of organic compounds is often unclear, and this requires critical investigation. This review describes the role of clay/modified clay minerals in hydrocarbon bioremediation through interaction with microbial agents in specific scenarios. The vision is on a faster, more efficient and cost-effective bioremediation technique using clay-based products. This review also proposes future research directions in the field of clay modulated microbial degradation of hydrocarbons. Copyright © 2015 Elsevier Ltd. All rights reserved.

Advances and perspective in bioremediation of polychlorinated biphenyl-contaminated soils.

PubMed

Sharma, Jitendra K; Gautam, Ravindra K; Nanekar, Sneha V; Weber, Roland; Singh, Brajesh K; Singh, Sanjeev K; Juwarkar, Asha A

2018-06-01

In recent years, microbial degradation and bioremediation approaches of polychlorinated biphenyls (PCBs) have been studied extensively considering their toxicity, carcinogenicity and persistency potential in the environment. In this direction, different catabolic enzymes have been identified and reported for biodegradation of different PCB congeners along with optimization of biological processes. A genome analysis of PCB-degrading bacteria has led in an improved understanding of their metabolic potential and adaptation to stressful conditions. However, many stones in this area are left unturned. For example, the role and diversity of uncultivable microbes in PCB degradation are still not fully understood. Improved knowledge and understanding on this front will open up new avenues for improved bioremediation technologies which will bring economic, environmental and societal benefits. This article highlights on recent advances in bioremediation of PCBs in soil. It is demonstrated that bioremediation is the most effective and innovative technology which includes biostimulation, bioaugmentation, phytoremediation and rhizoremediation and acts as a model solution for pollution abatement. More recently, transgenic plants and genetically modified microorganisms have proved to be revolutionary in the bioremediation of PCBs. Additionally, other important aspects such as pretreatment using chemical/physical agents for enhanced biodegradation are also addressed. Efforts have been made to identify challenges, research gaps and necessary approaches which in future, can be harnessed for successful use of bioremediation under field conditions. Emphases have been given on the quality/efficiency of bioremediation technology and its related cost which determines its ultimate acceptability.

Arsenic and uranium in private wells in Connecticut, 2013-15

USGS Publications Warehouse

Flanagan, Sarah M.; Brown, Craig J.

2017-05-03

The occurrence of arsenic and uranium in groundwater at concentrations that exceed drinking-water standards is a concern because of the potential adverse effects on human health. Some early studies of arsenic occurrence in groundwater considered anthropogenic causes, but more recent studies have focused on sources of naturally occurring arsenic to groundwater, such as minerals within aquifer materials that are in contact with groundwater. Arsenic and uranium in groundwater in New England have been shown to have a strong association to the geologic setting and nearby streambed sediment concentrations. In New Hampshire and Massachusetts, arsenic and uranium concentrations greater than human-health benchmarks have shown distinct spatial patterns when related to the bedrock units mapped at the local scale.The Connecticut Department of Public Health (DPH) reported that there are about 322,600 private wells in Connecticut serving approximately 823,000 people, or 23 percent of the State’s population. The State does not require that existing private wells be routinely tested for arsenic, uranium, or other contaminants; consequently, private wells are only sampled at the well owner’s discretion or when they are newly constructed. The U.S. Geological Survey (USGS), in cooperation with the DPH, completed an assessment in 2016 on the distribution of concentrations of arsenic and uranium in groundwater from bedrock in Connecticut. This report presents the major findings for arsenic and uranium concentrations from water samples collected from 2013 to 2015 from private wells.

A Point Kinetics Model for Estimating Neutron Multiplication of Bare Uranium Metal in Tagged Neutron Measurements

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

Tweardy, Matthew C.; McConchie, Seth; Hayward, Jason P.

An extension of the point kinetics model is developed in this paper to describe the neutron multiplicity response of a bare uranium object under interrogation by an associated particle imaging deuterium-tritium (D-T) measurement system. This extended model is used to estimate the total neutron multiplication of the uranium. Both MCNPX-PoliMi simulations and data from active interrogation measurements of highly enriched and depleted uranium geometries are used to evaluate the potential of this method and to identify the sources of systematic error. The detection efficiency correction for measured coincidence response is identified as a large source of systematic error. If themore » detection process is not considered, results suggest that the method can estimate total multiplication to within 13% of the simulated value. Values for multiplicity constants in the point kinetics equations are sensitive to enrichment due to (n, xn) interactions by D-T neutrons and can introduce another significant source of systematic bias. This can theoretically be corrected if isotopic composition is known a priori. Finally, the spatial dependence of multiplication is also suspected of introducing further systematic bias for high multiplication uranium objects.« less

A Point Kinetics Model for Estimating Neutron Multiplication of Bare Uranium Metal in Tagged Neutron Measurements

DOE PAGES

Tweardy, Matthew C.; McConchie, Seth; Hayward, Jason P.

2017-06-13

An extension of the point kinetics model is developed in this paper to describe the neutron multiplicity response of a bare uranium object under interrogation by an associated particle imaging deuterium-tritium (D-T) measurement system. This extended model is used to estimate the total neutron multiplication of the uranium. Both MCNPX-PoliMi simulations and data from active interrogation measurements of highly enriched and depleted uranium geometries are used to evaluate the potential of this method and to identify the sources of systematic error. The detection efficiency correction for measured coincidence response is identified as a large source of systematic error. If themore » detection process is not considered, results suggest that the method can estimate total multiplication to within 13% of the simulated value. Values for multiplicity constants in the point kinetics equations are sensitive to enrichment due to (n, xn) interactions by D-T neutrons and can introduce another significant source of systematic bias. This can theoretically be corrected if isotopic composition is known a priori. Finally, the spatial dependence of multiplication is also suspected of introducing further systematic bias for high multiplication uranium objects.« less

BIOREMEDIATION FIELD EVALUATION: EIELSON AIR FORCE BASE, ALASKA (EPA/540/R-95/533)

EPA Science Inventory

This publication, one of a series presenting the findings of the Bioremediation Field Initiatives bioremediation field evaluations, provides a detailed summary of the evaluation conducted at the Eielson Air Force Base (AFB) Superfund site in Fairbanks, Alaska. At this site, the ...

40 CFR 300.920 - Addition of products to Schedule.

Code of Federal Regulations, 2011 CFR

2011-07-01

... manufacturer of his decision in writing. (b) Surface washing agents, surface collecting agents, bioremediation... collecting agent, bioremediation agent, or miscellaneous oil spill control agent to the NCP Product Schedule... collecting agent, bioremediation agent, or miscellaneous oil spill control agent. On the basis of this data...

40 CFR 300.920 - Addition of products to Schedule.

Code of Federal Regulations, 2014 CFR

2014-07-01

... manufacturer of his decision in writing. (b) Surface washing agents, surface collecting agents, bioremediation... collecting agent, bioremediation agent, or miscellaneous oil spill control agent to the NCP Product Schedule... collecting agent, bioremediation agent, or miscellaneous oil spill control agent. On the basis of this data...

40 CFR 300.920 - Addition of products to Schedule.

Code of Federal Regulations, 2012 CFR

2012-07-01

... manufacturer of his decision in writing. (b) Surface washing agents, surface collecting agents, bioremediation... collecting agent, bioremediation agent, or miscellaneous oil spill control agent to the NCP Product Schedule... collecting agent, bioremediation agent, or miscellaneous oil spill control agent. On the basis of this data...

40 CFR 300.920 - Addition of products to Schedule.

Code of Federal Regulations, 2013 CFR

2013-07-01

... manufacturer of his decision in writing. (b) Surface washing agents, surface collecting agents, bioremediation... collecting agent, bioremediation agent, or miscellaneous oil spill control agent to the NCP Product Schedule... collecting agent, bioremediation agent, or miscellaneous oil spill control agent. On the basis of this data...

40 CFR 300.920 - Addition of products to Schedule.

Code of Federal Regulations, 2010 CFR

2010-07-01

... manufacturer of his decision in writing. (b) Surface washing agents, surface collecting agents, bioremediation... collecting agent, bioremediation agent, or miscellaneous oil spill control agent to the NCP Product Schedule... collecting agent, bioremediation agent, or miscellaneous oil spill control agent. On the basis of this data...

GENOTOXICITY OF BIOREMEDIATED SOILS FROM THE REILLY TARSITE, ST. LOUIS PARK, MINNESOTA

EPA Science Inventory

An in vitro approach was used to measure the genotoxicity of creosote-contaminated soil before and after four bioremediation processes. The soil was taken from the Reilly Tar site, a closed Superfund site in Saint Louis Park, Minnesota. The creosote soil was bioremediated in bios...

J.R. SIMPLOT EX-SITU BIOREMEDIATION TECHNOLOGY FOR TREATMENT OF TNT-CONTAMINATED SOILS - INNOVATIVE TECHNOLOGY EVALUATION REPORT

EPA Science Inventory

This report summarizes the findings of the second evaluation of the J.R. Simplot Ex-situ Bioremediation Technology also known as the Simplot Anaerobic Bioremediation (SABRE™) process. This technology was developed by the J.R. Simplot Company to biologically degrade nitroaromatic...

Bioremediation Well Borehole Soil Sampling and Data Analysis Summary Report for the 100-N Area Bioremediation Project

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

D. A. Gamon

2009-09-28

The purpose of this report is to present data and findings acquired during the drilling and construction of seven bioremediation wells in the 100-N Area in conjunction with remediation of the UPR-100-N-17 petroleum waste site.

Bioremediation techniques applied to aqueous media contaminated with mercury.

PubMed

Velásquez-Riaño, Möritz; Benavides-Otaya, Holman D

2016-12-01

In recent years, the environmental and human health impacts of mercury contamination have driven the search for alternative, eco-efficient techniques different from the traditional physicochemical methods for treating this metal. One of these alternative processes is bioremediation. A comprehensive analysis of the different variables that can affect this process is presented. It focuses on determining the effectiveness of different techniques of bioremediation, with a specific consideration of three variables: the removal percentage, time needed for bioremediation and initial concentration of mercury to be treated in an aqueous medium.

Genetic Analysis of Stress Responses in Soil Bacteria for Enhanced Bioremediation of Mixed Contaminants

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

Wong, Kwong-Kwok

The purpose of this project is to provide fundamental knowledge on environment stress response of subsurface bacteria and a radiation-resistant bacterium (Deinococcus radiodurans). This information will be particularly useful in the development of successful bioremediation strategies. These organisms represent two phylogenetically distinct groups of soil bacteria, each of which has specific features of interest for bioremediation. The subsurface bacteria, Sphingomonas spp (Savannah River Site), have unique degradative capabilities of organic waste. The study of subsurface bacteria will serve as a model for bioremediation using indigenous bacteria. D. radiodurans exhibits high resistance to external stress such as ionizing radiation and organicmore » solvent. The study of D. radiodurans will serve as a model for the use of genetically engineered bacteria for bioremediation.« less

Ecotoxicity monitoring and bioindicator screening of oil-contaminated soil during bioremediation.

PubMed

Shen, Weihang; Zhu, Nengwu; Cui, Jiaying; Wang, Huajin; Dang, Zhi; Wu, Pingxiao; Luo, Yidan; Shi, Chaohong

2016-02-01

A series of toxicity bioassays was conducted to monitor the ecotoxicity of soils in the different phases of bioremediation. Artificially oil-contaminated soil was inoculated with a petroleum hydrocarbon-degrading bacterial consortium containing Burkholderia cepacia GS3C, Sphingomonas GY2B and Pandoraea pnomenusa GP3B strains adapted to crude oil. Soil ecotoxicity in different phases of bioremediation was examined by monitoring total petroleum hydrocarbons, soil enzyme activities, phytotoxicity (inhibition of seed germination and plant growth), malonaldehyde content, superoxide dismutase activity and bacterial luminescence. Although the total petroleum hydrocarbon (TPH) concentration in soil was reduced by 64.4%, forty days after bioremediation, the phytotoxicity and Photobacterium phosphoreum ecotoxicity test results indicated an initial increase in ecotoxicity, suggesting the formation of intermediate metabolites characterized by high toxicity and low bioavailability during bioremediation. The ecotoxicity values are a more valid indicator for evaluating the effectiveness of bioremediation techniques compared with only using the total petroleum hydrocarbon concentrations. Among all of the potential indicators that could be used to evaluate the effectiveness of bioremediation techniques, soil enzyme activities, phytotoxicity (inhibition of plant height, shoot weight and root fresh weight), malonaldehyde content, superoxide dismutase activity and luminescence of P. phosphoreum were the most sensitive. Copyright © 2015 Elsevier Inc. All rights reserved.

Radium and uranium concentrations and associated hydrogeochemistry in ground water in southwestern Pueblo County, Colorado

USGS Publications Warehouse

Felmlee, J. Karen; Cadigan, Robert Allen

1979-01-01

Radium and uranium concentrations in water from 37 wells tapping the aquifer system of the Dakota Sandstone and Purgatoire Formation in southwestern Pueblo County, Colorado, have a wide range of values and define several areas of high radioactivity in the ground water. Radium ranges from 0.3 to 420 picocuries per liter and has a median value of 8.8, and uranium ranges from 0.02 to 180 micrograms per liter and has a median value of 2.4. Radon concentrations, measured in 32 of the 37 wells, range from less than 100 picocuries per liter to as much as 27,000 and have a median value of 580. Relationships among the radioactive elements and 28 other geochemical parameters were studied by using correlation coefficients and R-mode factor analysis. Five factor groups were determined to represent major influences on water chemistry: (1) short-term solution reactions, (2) oxidation reactions, (3) hydrolysis reactions, (4) uranium distribution, and (5) long-term solution reactions. Uranium concentrations are most strongly influenced by oxidation reactions but also are affected by solution reactions and distribution of uranium in the rocks of the aquifer system. Radon and radium concentrations are mostly controlled by uranium distribution; radium also shows a moderate negative relationship with oxidation. To explain the statistical and spatial relationships among the parameters, a model was developed involving the selective leaching of uranium-bearing phases and metal sulfides which occur in discontinuous zones in sandstone and shale. When reducing conditions prevail, uranium is immobile, but radium can be taken into solution. When faults and associated fractured rocks allow oxidizing conditions to dominate, uranium can be taken into solution; radium can also be taken into solution, or it may become immobilized by coprecipitation with iron and manganese oxides or with barite. Several areas within the study area are discussed in terms of the model.

Spatial clustering of toxic trace elements in adolescents around the Torreón, Mexico lead-zinc smelter.

PubMed

Garcia-Vargas, Gonzalo G; Rothenberg, Stephen J; Silbergeld, Ellen K; Weaver, Virginia; Zamoiski, Rachel; Resnick, Carol; Rubio-Andrade, Marisela; Parsons, Patrick J; Steuerwald, Amy J; Navas-Acién, Ana; Guallar, Eliseo

2014-11-01

High blood lead (BPb) levels in children and elevated soil and dust arsenic, cadmium, and lead were previously found in Torreón, northern Mexico, host to the world's fourth largest lead-zinc metal smelter. The objectives of this study were to determine spatial distributions of adolescents with higher BPb and creatinine-corrected urine total arsenic, cadmium, molybdenum, thallium, and uranium around the smelter. Cross-sectional study of 512 male and female subjects 12-15 years of age was conducted. We measured BPb by graphite furnace atomic absorption spectrometry and urine trace elements by inductively coupled plasma-mass spectrometry, with dynamic reaction cell mode for arsenic. We constructed multiple regression models including sociodemographic variables and adjusted for subject residence spatial correlation with spatial lag or error terms. We applied local indicators of spatial association statistics to model residuals to identify hot spots of significant spatial clusters of subjects with higher trace elements. We found spatial clusters of subjects with elevated BPb (range 3.6-14.7 μg/dl) and urine cadmium (0.18-1.14 μg/g creatinine) adjacent to and downwind of the smelter and elevated urine thallium (0.28-0.93 μg/g creatinine) and uranium (0.07-0.13 μg/g creatinine) near ore transport routes, former waste, and industrial discharge sites. The conclusion derived from this study was that spatial clustering of adolescents with high BPb and urine cadmium adjacent to and downwind of the smelter and residual waste pile, areas identified over a decade ago with high lead and cadmium in soil and dust, suggests that past and/or present plant operations continue to present health risks to children in those neighborhoods.

Spatial clustering of toxic trace elements in adolescents around the Torreón, Mexico lead–zinc smelter

PubMed Central

Garcia-Vargas, Gonzalo G.; Rothenberg, Stephen J.; Silbergeld, Ellen K.; Weaver, Virginia; Zamoiski, Rachel; Resnick, Carol; Rubio-Andrade, Marisela; Parsons, Patrick J.; Steuerwald, Amy J.; Navas-Acién, Ana; Guallar, Eliseo

2016-01-01

High blood lead (BPb) levels in children and elevated soil and dust arsenic, cadmium, and lead were previously found in Torreón, northern Mexico, host to the world’s fourth largest lead–zinc metal smelter. The objectives of this study were to determine spatial distributions of adolescents with higher BPb and creatinine-corrected urine total arsenic, cadmium, molybdenum, thallium, and uranium around the smelter. Cross-sectional study of 512 male and female subjects 12–15 years of age was conducted. We measured BPb by graphite furnace atomic absorption spectrometry and urine trace elements by inductively coupled plasma-mass spectrometry, with dynamic reaction cell mode for arsenic. We constructed multiple regression models including sociodemographic variables and adjusted for subject residence spatial correlation with spatial lag or error terms. We applied local indicators of spatial association statistics to model residuals to identify hot spots of significant spatial clusters of subjects with higher trace elements. We found spatial clusters of subjects with elevated BPb (range 3.6–14.7 µg/dl) and urine cadmium (0.18–1.14 µg/g creatinine) adjacent to and downwind of the smelter and elevated urine thallium (0.28–0.93 µg/g creatinine) and uranium (0.07–0.13 µg/g creatinine) near ore transport routes, former waste, and industrial discharge sites. The conclusion derived from this study was that spatial clustering of adolescents with high BPb and urine cadmium adjacent to and downwind of the smelter and residual waste pile, areas identified over a decade ago with high lead and cadmium in soil and dust, suggests that past and/or present plant operations continue to present health risks to children in those neighborhoods. PMID:24549228

CHAMPION INTERNATIONAL SUPERFUND SITE, LIBBY MONTANA FIELD PERFORMANCE EVALUATION BIOREMEDIATION UNIT: IN SITU BIOREMEDIATION OF THE UPPER AQUIFER

EPA Science Inventory

The field performance evaluation of the in-situ bioremediation system at Libby, Montana Superfund Site indicated that treatment appears to have occurred in the water phase under the influence of the treatment injection system. Reduced inorganic compounds may have exerted a deman...

75 FR 38809 - Agency Information Collection Activities; Submission to OMB for Review and Approval; Comment...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-06

... addition, at 40 CFR 300.915(d), EPA requires respondents to test bioremediation agents for effectiveness, using the testing protocol contained in Appendix C to part 300. The Bioremediation Agent Effectiveness Test is used to compare the effectiveness of different bioremediation agents. The objective of the...

New Developments in 1,4 Dioxane Site Management

DTIC Science & Technology

2016-11-01

oxidation, enhanced bioremediation , site management. Unclassified Unclassified UU UL 8 David Adamson (713) 522-6300 Page Intentionally Left Blank...there was little indication that chlorinated solvent remedial efforts (e.g., chemical oxidation, enhanced bioremediation ) impacted 1,4-dioxane...oxidation may prove beneficial for subsequent biologically- based approaches, including both enhanced bioremediation and natural attenuation. FOR

Epithermal uranium deposits in a volcanogenic context: the example of Nopal 1 deposit, Sierra de Pena Blanca, Mexico

NASA Astrophysics Data System (ADS)

Calas, G.; Angiboust, S.; Fayek, M.; Camacho, A.; Allard, T.; Agrinier, P.

2009-12-01

The Peña Blanca molybdenum-uranium field (Chihuahua, Mexico) exhibits over 100 airborne anomalies hosted in tertiary ignimbritic ash-flow tuffs (44 Ma) overlying the Pozos conglomerate and a sequence of Cretaceous carbonate rocks. Uranium occurrences are associated with breccia zones at the intersection of two or more fault systems. Periodic reactivation of these structures associated with Basin and Range and Rio Grande tectonic events resulted in the mobilization of U and other elements by meteoric fluids heated by geothermal activity. Trace element geochemistry (U, Th, REE) provides evidence for local mobilization of uranium under oxidizing conditions. In addition, O- and H-isotope geochemistry of kaolinite, smectite, opal and calcite suggests that argillic alteration proceeded at shallow depth with meteoric water at 25-75 °C. Focussed along breccia zones, fluids precipitated several generations of pyrite and uraninite together with kaolinite, as in the Nopal 1 mine, indicating that mineralization and hydrothermal alteration of volcanic tuffs are contemporaneous. Low δ34S values (~ -24.5 ‰) of pyrites intimately associated with uraninite suggest that the reducing conditions at the origin of the U-mineralization arise from biological activity. Later, the uplift of Sierra Pena Blanca resulted in oxidation and remobilization of uranium, as confirmed by the spatial distribution of radiation-induced defect centers in kaolinites. These data show that tectonism and biogenic reducing conditions can play a major role in the formation and remobilization of uranium in epithermal deposits. By comparison with the other uranium deposits at Sierra Pena Blanca and nearby Sierra de Gomez, Nopal 1 deposit is one of the few deposits having retained a reduced uranium mineralization.

Image fusion of Secondary Ion Mass Spectrometry and Energy-dispersive X-Ray Spectroscopy data for the characterization of uranium-molybdenum fuel foils

NASA Astrophysics Data System (ADS)

Willingham, David; Naes, Benjamin E.; Tarolli, Jay G.; Schemer-Kohrn, Alan; Rhodes, Mark; Dahl, Michael; Guzman, Anthony; Burkes, Douglas E.

2018-01-01

Uranium-molybdenum (U-Mo) monolithic fuels represent one option for converting civilian research and test reactors operating with high enriched uranium (HEU) to low enriched uranium (LEU), effectively reducing the threat of nuclear proliferation world-wide. However, processes associated with fabrication of U-Mo monolithic fuels result in regions of elemental heterogeneity, observed as bands traversing the cross-section of representative samples. Isotopic variations (e.g., 235U and 238U) could also be introduced because of associated processing steps, particularly since HEU feedstock is melted with natural or depleted uranium diluent to produce LEU. This study demonstrates the utility of correlative analysis of Energy-Dispersive X-ray Spectroscopy (EDS) and Secondary Ion Mass Spectrometry (SIMS) with their image data streams using image fusion, resulting in a comprehensive microanalytical characterization toolbox. Elemental and isotopic measurements were made on a sample from the Advanced Test Reactor (ATR) Full-sized plate In-center flux trap Position (AFIP)-7 experiment and compared to previous optical and electron microscopy results. The image fusion results are characteristic of SIMS isotopic maps, but with the spatial resolution of EDS images and, therefore, can be used to increase the effective spatial resolution of the SIMS imaging results to better understand homogeneity or heterogeneity that persists because of processing selections. Visual inspection using the image fusion methodology indicated slight variations in the 235U/238U ratio and quantitative analysis using the image intensities across several FoVs revealed an average 235U atom percent value of 17.9 ± 2.4%, which was indicative of a non-uniform U isotopic distribution in the area sampled. Further development of this capability is useful for understanding the connections between the properties of LEU fuel alternatives and the ability to predict performance under irradiation.

Radiometric surveying for the assessment of radiation dose and radon specific exhalation in underground environment

NASA Astrophysics Data System (ADS)

Bochiolo, M.; Verdoya, M.; Chiozzi, P.; Pasquale, V.

2012-08-01

We performed a radiometric survey for evaluating the natural radioactivity and the related potential hazard level both outdoor and indoor a mine tunnel. The mine is located in a zone of uranium enrichment in the Western Alps (Italy). At first, a γ-ray spectrometry survey of the area surrounding the mine was carried out to define the extent of the ore deposit. Then, spectrometric measurements were performed in the tunnel and rock samples were collected for laboratory analyses. The results point to significant heterogeneity in uranium concentration and consequently in the absorbed dose rate spatial distribution. Spectrometric results in situ and in the laboratory, together with radon air concentration measurements, were used to infer the radon specific exhalation and flow from the mine rocks. The specific exhalation is positively related to the activity concentration of uranium.

Emerging technologies in bioremediation: constraints and opportunities.

PubMed

Rayu, Smriti; Karpouzas, Dimitrios G; Singh, Brajesh K

2012-11-01

Intensive industrialisation, inadequate disposal, large-scale manufacturing activities and leaks of organic compounds have resulted in long-term persistent sources of contamination of soil and groundwater. This is a major environmental, policy and health issue because of adverse effects of contaminants on humans and ecosystems. Current technologies for remediation of contaminated sites include chemical and physical remediation, incineration and bioremediation. With recent advancements, bioremediation offers an environmentally friendly, economically viable and socially acceptable option to remove contaminants from the environment. Three main approaches of bioremediation include use of microbes, plants and enzymatic remediation. All three approaches have been used with some success but are limited by various confounding factors. In this paper, we provide a brief overview on the approaches, their limitations and highlights emerging technologies that have potential to revolutionise the enzymatic and plant-based bioremediation approaches.

Modulation of Medium pH by Caulobacter crescentus Facilitates Recovery from Uranium-Induced Growth Arrest

PubMed Central

Park, Dan M.

2014-01-01

The oxidized form of uranium [U(VI)] predominates in oxic environments and poses a major threat to ecosystems. Due to its ability to mineralize U(VI), the oligotroph Caulobacter crescentus is an attractive candidate for U(VI) bioremediation. However, the physiological basis for U(VI) tolerance is unclear. Here we demonstrated that U(VI) caused a temporary growth arrest in C. crescentus and three other bacterial species, although the duration of growth arrest was significantly shorter for C. crescentus. During the majority of the growth arrest period, cell morphology was unaltered and DNA replication initiation was inhibited. However, during the transition from growth arrest to exponential phase, cells with shorter stalks were observed, suggesting a decoupling between stalk development and the cell cycle. Upon recovery from growth arrest, C. crescentus proliferated with a growth rate comparable to that of a control without U(VI), although a fraction of these cells appeared filamentous with multiple replication start sites. Normal cell morphology was restored by the end of exponential phase. Cells did not accumulate U(VI) resistance mutations during the prolonged growth arrest, but rather, a reduction in U(VI) toxicity occurred concomitantly with an increase in medium pH. Together, these data suggest that C. crescentus recovers from U(VI)-induced growth arrest by reducing U(VI) toxicity through pH modulation. Our finding represents a unique U(VI) detoxification strategy and provides insight into how microbes cope with U(VI) under nongrowing conditions, a metabolic state that is prevalent in natural environments. PMID:25002429

Hydrogeophysical imaging of deposit heterogeneity and groundwater chemistry changes during DNAPL source zone bioremediation.

PubMed

Chambers, J E; Wilkinson, P B; Wealthall, G P; Loke, M H; Dearden, R; Wilson, R; Allen, D; Ogilvy, R D

2010-10-21

Robust characterization and monitoring of dense nonaqueous phase liquid (DNAPL) source zones is essential for designing effective remediation strategies, and for assessing the efficacy of treatment. In this study high-resolution cross-hole electrical resistivity tomography (ERT) was evaluated as a means of monitoring a field-scale in-situ bioremediation experiment, in which emulsified vegetable oil (EVO) electron donor was injected into a trichloroethene source zone. Baseline ERT scans delineated the geometry of the interface between the contaminated alluvial aquifer and the underlying mudstone bedrock, and also the extent of drilling-induced physical heterogeneity. Time-lapse ERT images revealed major preferential flow pathways in the source and plume zones, which were corroborated by multiple lines of evidence, including geochemical monitoring and hydraulic testing using high density multilevel sampler arrays within the geophysical imaging planes. These pathways were shown to control the spatial distribution of the injected EVO, and a bicarbonate buffer introduced into the cell for pH control. Resistivity signatures were observed within the preferential flow pathways that were consistent with elevated chloride levels, providing tentative evidence from ERT of the biodegradation of chlorinated solvents. Copyright © 2010 S. Yamamoto. Published by Elsevier B.V. All rights reserved.

Uranium in Surface Waters and Sediments Affected by Historical Mining in the Denver West 1:100,000 Quadrangle, Colorado

USGS Publications Warehouse

Zielinski, Robert A.; Otton, James K.; Schumann, R. Randall; Wirt, Laurie

2008-01-01

Geochemical sampling of 82 stream waters and 87 stream sediments within mountainous areas immediately west of Denver, Colorado, was conducted by the U.S. Geological Survey in October 1994. The primary purpose was to evaluate regionally the effects of geology and past mining on the concentration and distribution of uranium. The study area contains uranium- and thorium-rich bedrock, numerous noneconomic occurrences of uranium minerals, and several uranium deposits of variable size and production history. During the sampling period, local streams had low discharge and were more susceptible to uranium-bearing acid drainage originating from historical mines of base- and precious-metal sulfides. Results indicated that the spatial distribution of Precambrian granites and metamorphic rocks strongly influences the concentration of uranium in stream sediments. Within-stream transport increases the dispersion of uranium- and thorium rich mineral grains derived primarily from granitic source rocks. Dissolved uranium occurs predominantly as uranyl carbonate complexes, and concentrations ranged from less than 1 to 65 micrograms per liter. Most values were less than 5 micrograms per liter, which is less than the current drinking water standard of 30 micrograms per liter and much less than locally applied aquatic-life toxicity standards of several hundred micrograms per liter. In local streams that are affected by uranium-bearing acid mine drainage, dissolved uranium is moderated by dilution and sorptive uptake by stream sediments. Sorbents include mineral alteration products and chemical precipitates of iron- and aluminum-oxyhydroxides, which form where acid drainage enters streams and is neutralized. Suspended uranium is relatively abundant in some stream segments affected by nearby acid drainage, which likely represents mobilization of these chemical precipitates. The 234U/238U activity ratio of acid drainage (0.95-1.0) is distinct from that of local surface waters (more than 1.05), and this distinctive isotopic composition may be preserved in iron-oxyhydroxide precipitates of acid drainage origin. The study area includes a particularly large vein-type uranium deposit (Schwartzwalder mine) with past uranium production. Stream water and sediment collected downstream from the mine's surface operations have locally anomalous concentrations of uranium. Fine-grained sediments downstream from the mine contain rare minute particles (10-20 micrometers) of uraninite, which is unstable in a stream environment and thus probably of recent origin related to mining. Additional rare particles of very fine grained (less than 5 micrometer) barite likely entered the stream as discharge from settling ponds in which barite precipitation was formerly used to scavenge dissolved radium from mine effluent.

INFLUENCE OF TIDE AND WAVES ON WASHOUT OF DISSOLVED NUTRIENTS FROM THE BIOREMEDIATION ZONE OF A COARSE-SAND BEACH: APPLICATION IN OIL-SPILL BIOREMEDIATION

EPA Science Inventory

Successful bioremediation of oil-contaminated beaches requires maintenance of a sufficient quantity of growth-limiting nutrients in contact with the oiled beach materials. A conservative tracer study was conducted on a moderate-energy, sandy beach on Delaware Bay to estimate the...

In Situ Bioremediation of Chlorinated Ethenes in Hydraulically-Tight Sediments: Challenges and Limitations

NASA Astrophysics Data System (ADS)

Zhang, M.; Yoshikawa, M.; Takeuchi, M.; Komai, T.

2011-12-01

Chlorinated ethenes, like perchloroethene (PCE) and trichloroethene (TCE), have been widely used by many industries, especially in developed countries like Japan. Because of their wide applications, lack of proper regulation, poor handing, storage and disposal practices in the past, chlorinated ethenes have become a type of the most prevalent contaminants for soils and groundwater pollution. For the sake of their degradability, bioremediation has been considered as a potentially cost-effective and environmentally friendly approach for cleanup of chlorinated ethenes in situ. In this presentation, we briefly overview the status of soil and groundwater pollution, the recent amendment of the Soil Contamination Countermeasures Act in Japan, comparison between the bioremediation and other techniques like pump and treat, and the mechanisms of reductive dechlorination, direct oxidation and co-metabolism of chlorinated ethenes. We then introduce and discuss some recent challenges and advancements in in-situ bioremediation including technologies for accelerating bio-degradation of chlorinated ethenes, technologies for assessing diffusive properties of dissolved hydrogen in hydraulically-tight soil samples, and combination of bioremediation with other techniques like electro-kinetic approach. Limiting factors that may cause incomplete remediation and/or ineffectiveness of bioremediation are examined from biochemical, geochemical and hydro-geological aspects. This study reconfirmed and illustrated that: 1) The key factor for an effective bioremediation is how to disperse a proper accelerating agent throughout the polluted strata, 2) The effective diffusion coefficient of dissolved hydrogen in geologic media is relatively big and is almost independent on their permeability, and 3) To effectively design and perform an accelerated bioremediation, a combination of natural migration with pressurized injection and/or other approaches, like electro-migration, for stimulating mass transport could be necessary depending on the hydraulic properties, like porosity and permeability of a stratum.

Using a Consensus Conference to Characterize Regulatory Concerns Regarding Bioremediation of Radionuclides and Heavy Metals in Mixed Waste at DOE Sites

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

Denise Lach; Stephanie Sanford

2006-09-01

A consensus workshop was developed and convened with ten state regulators to characterize concerns regarding emerging bioremediation technology to be used to clean-up radionuclides and heavy metals in mixed wastes at US DOE sites. Two questions were explored: integrated questions: (1) What impact does participation in a consensus workshop have on the knowledge, attitudes, and practices of state regulators regarding bioremediation technology? (2) How effective is a consensus workshop as a strategy for eliciting and articulating regulators’ concerns regarding the use of bioremediation to clean up radionuclides and heavy metals in mixed wastes at U.S. Department of Energy Sites aroundmore » the county? State regulators met together for five days over two months to learn about bioremediation technology and develop a consensus report of their recommendations regarding state regulatory concerns. In summary we found that panel members: - quickly grasped the science related to bioremediation and were able to effectively interact with scientists working on complicated issues related to the development and implementation of the technology; - are generally accepting of in situ bioremediation, but concerned about costs, implementation (e.g., institutional controls), and long-term effectiveness of the technology; - are concerned equally about technological and implementation issues; and - believed that the consensus workshop approach to learning about bioremediation was appropriate and useful. Finally, regulators wanted decision makers at US DOE to know they are willing to work with DOE regarding innovative approaches to clean-up at their sites, and consider a strong relationship between states and the DOE as critical to any effective clean-up. They do not want perceive themselves to be and do not want others to perceive them as barriers to successful clean-up at their sites.« less

Mathematical modeling of the integrated process of mercury bioremediation in the industrial bioreactor.

PubMed

Głuszcz, Paweł; Petera, Jerzy; Ledakowicz, Stanisław

2011-03-01

The mathematical model of the integrated process of mercury contaminated wastewater bioremediation in a fixed-bed industrial bioreactor is presented. An activated carbon packing in the bioreactor plays the role of an adsorbent for ionic mercury and at the same time of a carrier material for immobilization of mercury-reducing bacteria. The model includes three basic stages of the bioremediation process: mass transfer in the liquid phase, adsorption of mercury onto activated carbon and ionic mercury bioreduction to Hg(0) by immobilized microorganisms. Model calculations were verified using experimental data obtained during the process of industrial wastewater bioremediation in the bioreactor of 1 m³ volume. It was found that the presented model reflects the properties of the real system quite well. Numerical simulation of the bioremediation process confirmed the experimentally observed positive effect of the integration of ionic mercury adsorption and bioreduction in one apparatus.

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

NASA Astrophysics Data System (ADS)

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

2018-02-01

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

[Bioremediation of oil-polluted soils: using the [13C]/[12C] ratio to characterize microbial products of oil hydrocarbon biodegradation].

PubMed

Ziakun, A M; Brodskiĭ, E S; Baskunov, B P; Zakharchenko, V N; Peshenko, V P; Filonov, A E; Vetrova, A A; Ivanova, A A; Boronin, A M

2014-01-01

We compared data on the extent of bioremediation in soils polluted with oil. The data were obtained using conventional methods of hydrocarbon determination: extraction gas chromatography-mass spectrometry, extraction IR spectroscopy, and extraction gravimetry. Due to differences in the relative abundances of the stable carbon isotopes (13C/12C) in oil and in soil organic matter, these ratios could be used as natural isotopic labels of either substance. Extraction gravimetry in combination with characteristics of the carbon isotope composition of organic products in the soil before and after bioremediation was shown to be the most informative approach to an evaluation of soil bioremediation. At present, it is the only method enabling quantification of the total petroleum hydrocarbons in oil-polluted soil, as well as of the amounts of hydrocarbons remaining after bioremediation and those microbially transformed into organic products and biomass.

Treatment of a mud pit by bioremediation.

PubMed

Avdalović, Jelena; Đurić, Aleksandra; Miletić, Srdjan; Ilić, Mila; Milić, Jelena; Vrvić, Miroslav M

2016-08-01

The mud generated from oil and natural gas drilling, presents a considerable ecological problem. There are still insufficient remedies for the removal and minimization of these very stable emulsions. Existing technologies that are in use, more or less successfully, treat about 20% of generated waste drilling mud, while the rest is temporarily deposited in so-called mud pits. This study investigated in situ bioremediation of a mud pit. The bioremediation technology used in this case was based on the use of naturally occurring microorganisms, isolated from the contaminated site, which were capable of using the contaminating substances as nutrients. The bioremediation was stimulated through repeated inoculation with a zymogenous microbial consortium, along with mixing, watering and biostimulation. Application of these bioremediation techniques reduced the concentration of total petroleum hydrocarbons from 32.2 to 1.5 g kg(-1) (95% degradation) during six months of treatment. © The Author(s) 2016.

Structural basis for expanding the application of bioligand in metal bioremediation: A review.

PubMed

Sharma, Virbala; Pant, Deepak

2018-03-01

Bioligands (BL) present in plant and microbes are primarily responsible for their use in metal decontamination. Both primary (proteins and amino acid) and secondary (proliferated) response in the form of BL is possible in plants and microbes toward metal bioremediation. Structure of these BL have specific requirement for preferential binding towards a particular metal in biomass. The aim of this review is to explore various templates from BL (as metal host) for the metal detoxification/decontamination and associated bioremediation. Mechanistic explanation for bioremediation may involve the various processes like: (i) electron transfer; (ii) translocation; and (iii) coordination number variation. HSAB (hard and soft acid and base) concept can act as guiding principle for many such processes. It is possible to investigate various structural homolog of BL (similar to secondary response in living stage) for the possible improvement in bioremediation process. Copyright © 2017 Elsevier Ltd. All rights reserved.

Identification of Preferential Groundwater Flow Pathways from Local Tracer Breakthrough Curves

NASA Astrophysics Data System (ADS)

Kokkinaki, A.; Sleep, B. E.; Dearden, R.; Wealthall, G.

2009-12-01

Characterizing preferential groundwater flow paths in the subsurface is a key factor in the design of in situ remediation technologies. When applying reaction-based remediation methods, such as enhanced bioremediation, preferential flow paths result in fast solute migration and potentially ineffective delivery of reactants, thereby adversely affecting treatment efficiency. The presence of such subsurface conduits was observed at the SABRe (Source Area Bioremediation) research site. Non-uniform migration of contaminants and electron donor during the field trials of enhanced bioremediation supported this observation. To better determine the spatial flow field of the heterogeneous aquifer, a conservative tracer test was conducted. Breakthrough curves were obtained at a reference plane perpendicular to the principal groundwater flow direction. The resulting dataset was analyzed using three different methods: peak arrival times, analytical solution fitting and moment analysis. Interpretation using the peak arrival time method indicated areas of fast plume migration. However, some of the high velocities are supported by single data points, thus adding considerable uncertainty to the estimated velocity distribution. Observation of complete breakthrough curves indicated different types of solute breakthrough, corresponding to different transport mechanisms. Sharp peaks corresponded to high conductivity preferential flow pathways, whereas more dispersed breakthrough curves with long tails were characteristic of significant dispersive mixing and dilution. While analytical solutions adequately quantified flow characteristics for the first type of curves, they failed to do so for the second type, in which case they gave unrealistic results. Therefore, a temporal moment analysis was performed to obtain complete spatial distributions of mass recovery, velocity and dispersivity. Though the results of moment analysis qualitatively agreed with the results of previous methods, more realistic estimates of velocities were obtained and the presence of one major preferential flow pathway was confirmed. However, low mass recovery and deviations from the 10% scaling rule for dispersivities indicate that insufficient spatial and temporal monitoring, as well as interpolation and truncation errors introduced uncertainty in the flow and transport parameters estimated by the method of moments. The results of the three analyses are valuable for enhancing the understanding of mass transport and remediation performance. Comparing the different interpretation methods, increasing the amount of concentration data considered in the analysis, the derived velocity fields were smoother and the estimated local velocities and dispersivities became more realistic. In conclusion, moment analysis is a method that represents a smoothed average of the velocity across the entire breakthrough curve, whereas the peak arrival time, which may be a less well constrained estimate, represents the physical peak arrival and typically yields a higher velocity than the moment analysis. This is an important distinction when applying the results of the tracer test to field sites.

The Use of Enhanced Bioremediation at the Savannah River Site to Remediate Pesticides and PCBs

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

Beul, R.

2003-09-30

Enhanced bioremediation is quickly developing into an economical and viable technology for the remediation of contaminated soils. Until recently, chlorinated organic compounds have proven difficult to bioremediate. This article reviews the ongoing remediation occurring at the Chemicals, Metals, and Pesticides (CMP) Pits using windrow turners to facilitate microbial degradation of certain pesticides and PCBs.

Combining Low-Energy Electrical Resistance Heating with Biotic and Abiotic Reactions for Treatment of Chlorinated Solvent DNAPL Source Areas

DTIC Science & Technology

2015-01-01

5 2.1.2 In Situ Bioremediation ...Technology Certification Program gpm gallons per minute ISB in situ bioremediation JBLM Joint Base Lewis-McChord mmol millimole MROD Mount...EXECUTIVE SUMMARY BACKGROUND The applicability of in situ groundwater remedies such as in situ bioremediation (ISB) or zero valent iron (ZVI) reduction

New Approaches to Evaluate the Biological Degradation of RDX in Groundwater

DTIC Science & Technology

2014-08-27

biodegradation in groundwater. 15. SUBJECT TERMS RDX, hexahydro-1,3,5-trinitro-1,3,5-triazine, bioremediation , biodegradation, groundwater, stable...DoD sites for documenting in situ RDX biodegradation as a natural attenuation process or during bioremediation efforts. Moreover, the CSIA data...and nitroaromatic explosives from surface soils, including enhanced bioremediation , are well documented but there are presently few proven

Bio-rescue of marine environments: On the track of microbially-based metal/metalloid remediation.

PubMed

Marques, Catarina R

2016-09-15

The recent awareness of the huge relevance of marine resources and ecological services is driving regulatory demands for their protection from overwhelming contaminants, such as metals/metalloids. These contaminants enter and accumulate in different marine niches, hence deeply compromising their quality and integrity. Bioremediation has been flourishing to counteract metal/metalloid impacts, since it provides cost-effective and sustainable options by relying on ecology-based technologies. The potential of marine microbes for metal/metalloid bioremediation is the core of many studies, due to their high plasticity to overcome successive environmental hurdles. However, any thorough review on the advances of metal/metalloid bioremediation in marine environments was so far unveiled. This review is designed to (i) outline the characteristics and potential of marine microbes for metal/metalloid bioremediation, (ii) describe the underlying pathways of resistance and detoxification, as well as useful methodologies for their characterization, (iii) identify major bottlenecks on metal/metalloid bioremediation with marine microbes, (iv) present alternative strategies based on microbial consortia and engineered microbes for enhanced bioremediation, and (v) propose key research avenues to keep pace with a changing society, science and economy in a sustainable manner. Copyright © 2016 Elsevier B.V. All rights reserved.

Distribution of hydrocarbon-degrading bacteria in the soil environment and their contribution to bioremediation.

PubMed

Fukuhara, Yuki; Horii, Sachie; Matsuno, Toshihide; Matsumiya, Yoshiki; Mukai, Masaki; Kubo, Motoki

2013-05-01

A real-time PCR quantification method for indigenous hydrocarbon-degrading bacteria (HDB) carrying the alkB gene in the soil environment was developed to investigate their distribution in soil. The detection limit of indigenous HDB by the method was 1 × 10(6) cells/g-soil. The indigenous HDB were widely distributed throughout the soil environment and ranged from 3.7 × 10(7) to 5.0 × 10(8) cells/g-soil, and the ratio to total bacteria was 0.1-4.3 %. The dynamics of total bacteria, indigenous HDB, and Rhodococcus erythropolis NDKK6 (carrying alkB R2) during bioremediation were analyzed. During bioremediation with an inorganic nutrient treatment, the numbers of these bacteria were slightly increased. The numbers of HDB (both indigenous bacteria and strain NDKK6) were gradually decreased from the middle stage of bioremediation. Meanwhile, the numbers of these bacteria were highly increased and were maintained during bioremediation with an organic nutrient. The organic treatment led to activation of not only the soil bacteria but also the HDB, so an efficient bioremediation was carried out.

Lessons from the Navajo: assistance with environmental data collection ensures cultural humility and data relevance.

PubMed

DeLemos, Jamie; Rock, Tommy; Brugge, Doug; Slagowski, Naomi; Manning, Thomas; Lewis, Johnnye

2007-01-01

The Navajo Nation suffers from a legacy of environmental pollution from historical uranium mining activities, resulting in adverse public health outcomes and continuous exposure. Partner with a Navajo graduate student and community members in a field campaign to characterize the spatial distribution and geochemistry of uranium for a multipathway uranium exposure assessment under development by the Dine Network for Environmental Health (DiNEH) project. Attend community meetings, acquire Navajo language skills, and integrate local knowledge into sampling approach of sediment, water, and vegetation. Navajo participation (1) helped to foster trust in research efforts during community interactions, (2) taught aspects of Navajo culture and language to maintain positive and respectful relations, and (3) conveyed information on Navajo culture that would impact sampling strategies. Community engagement helps to sustain equitable partnerships and aids in culturally appropriate, relevant data collection.

Lessons from the Navajo: Assistance with Environmental Data Collection Ensures Cultural Humility and Data Relevance

PubMed Central

deLemos, Jamie; Rock, Tommy; Brugge, Doug; Slagowski, Naomi; Manning, Thomas; Lewis, Johnnye

2008-01-01

Background The Navajo Nation suffers from a legacy of environmental pollution from historical uranium mining activities, resulting in adverse public health outcomes and continuous exposure. Objective Partner with a Navajo graduate student and community members in a field campaign to characterize the spatial distribution and geochemistry of uranium for a multipathway uranium exposure assessment under development by the Dine Network for Environmental Health (DiNEH) project. Methods Attend community meetings, acquire Navajo language skills, and integrate local knowledge into sampling approach of sediment, water, and vegetation. Results Navajo participation (1) helped to foster trust in research efforts during community interactions, (2) taught aspects of Navajo culture and language to maintain positive and respectful relations, and (3) conveyed information on Navajo culture that would impact sampling strategies. Conclusions Community engagement helps to sustain equitable partnerships and aids in culturally appropriate, relevant data collection. PMID:19655034

Soliton microdynamics and thermal conductivity of uranium nitride at high temperatures

NASA Astrophysics Data System (ADS)

Dubovsky, O. A.; Orlov, A. V.; Semenov, V. A.

2011-09-01

The microdynamics of soliton waves and localized modes of nonlinear vibrations of the acoustic and optical types in uranium nitride has been investigated. It has been shown that, with an increase in the excitation energy in the spectral gap between the bands of optical and acoustic phonons, the energies of solitons increase, whereas the energies of local modes decrease. The previously experimentally observed unidentified quasi-resonant features, which shift in the gap with variations in the temperature, can represent the revealed soliton waves and local modes. The microdynamics of heat conduction of uranium nitride has been studied for the stochastic generation of soliton waves and local modes in the case of spatially distant energy absorption. The thermal conductivity coefficient determined from the temperature gradient and the absorbed energy flux insignificantly exceeds the experimentally observed values, which are decreased because of the presence of structural defects of different types in the material.

Preliminary report on the Comet area, Jefferson County, Montana

USGS Publications Warehouse

Becraft, George Earle

1953-01-01

Several radioactivity anomalies and a few specimens of sooty pitchblende and other uranium minerals have been found on the mine dumps of formerly productive base- and precious-metal mines along the Comet-Gray Eagle shear zone in the Comet area in southwestern Montana. The shear zone is from 50 to 200 feet wide and has been traced for at least 5? miles. It trends N. 80 ? W. across the northern part of the area and cuts the quartz monzonitic rocks of the Boulder batholith and younger silicic intrusive rocks, as well as prebatholithic volcanic rocks, and is in turn cut by dacite and andesite dikes. The youngest period of mineralization is represented by chalcedonic vein zones comprising one or more discontinuous stringers and veins of cryptocrystalline silica in silicified quartz monzonite and in alaskite that has not been appreciably silicified. In some places these zones contain no distinct chalcedonic veins but are represented only by silicified quartz monzonite. These zones locally contain uranium in association with very small amounts of pyrite, galena, ruby silver, arqentite, native silver, molybdenite, chalcopyrite, arsenopyrite, and barite. At the Free Enterprise mine, uranium has been produced from a narrow chalcedonic vein that contains disseminated secondary uranium minerals and local small pods of pitchblende and also from disseminated secondary uranium ,minerals in the adjacent quartz monzonite. Undiscovered deposits of uranium ore may occur spatially associated with the base- and precious-metal deposits along the Comet-Gray Eagle shear zone and with chalcedonic vein zones similar to the Free Enterprise.

Strategies for chromium bioremediation of tannery effluent.

PubMed

Garg, Satyendra Kumar; Tripathi, Manikant; Srinath, Thiruneelakantan

2012-01-01

Bioremediation offers the possibility of using living organisms (bacteria, fungi, algae,or plants), but primarily microorganisms, to degrade or remove environmental contaminants, and transform them into nontoxic or less-toxic forms. The major advantages of bioremediation over conventional physicochemical and biological treatment methods include low cost, good efficiency, minimization of chemicals, reduced quantity of secondary sludge, regeneration of cell biomass, and the possibility of recover-ing pollutant metals. Leather industries, which extensively employ chromium compounds in the tanning process, discharge spent-chromium-laden effluent into nearby water bodies. Worldwide, chromium is known to be one of the most common inorganic contaminants of groundwater at pollutant hazardous sites. Hexavalent chromium poses a health risk to all forms of life. Bioremediation of chromium extant in tannery waste involves different strategies that include biosorption, bioaccumulation,bioreduction, and immobilization of biomaterial(s). Biosorption is a nondirected physiochemical interaction that occurs between metal species and the cellular components of biological species. It is metabolism-dependent when living biomass is employed, and metabolism-independent in dead cell biomass. Dead cell biomass is much more effective than living cell biomass at biosorping heavy metals, including chromium. Bioaccumulation is a metabolically active process in living organisms that works through adsorption, intracellular accumulation, and bioprecipitation mechanisms. In bioreduction processes, microorganisms alter the oxidation/reduction state of toxic metals through direct or indirect biological and chemical process(es).Bioreduction of Cr6+ to Cr3+ not only decreases the chromium toxicity to living organisms, but also helps precipitate chromium at a neutral pH for further physical removal,thus offering promise as a bioremediation strategy. However, biosorption, bioaccumulation, and bioreduction methods that rely on free cells for bioremediation suffer from Cr6 toxicity, and cell damage. Therefore, immobilization of microbial cell biomass enhances bioremediation and renders industrial bioremediation processes more economically viable from reduced free-cells toxicity, easier separation of biosorbents from the tannery effluent, ability to achieve multiple biosorption cycles, and desorption (elution) of metal(s) from matrices for reuse. Thus, microbial bioremediation can be a cost competitive strategy and beneficial bioresource for removing many hazardous contaminants from tannery and other industrial wastes.

Bioprospecting of gum kondagogu (Cochlospermum gossypium) for bioremediation of uranium (VI) from aqueous solution and synthetic nuclear power reactor effluents.

PubMed

Sashidhar, R B; Selvi, S Kalaignana; Vinod, V T P; Kosuri, Tanuja; Raju, D; Karuna, R

2015-10-01

An ecofriendly green chemistry method using a natural biopolymer, Gum Kondagogu (GK) for the removal of U (VI) from aqueous, simulated nuclear effluents was studied. The adsorption characteristic of GK towards U (VI) from aqueous solution was studied at varied pH, contact time, adsorbent dose, initial U (VI) concentration and temperature using UV-Visible spectroscopy and ICP-MS. Maximum adsorption was seen at pH 4, 0.1% GK with 60 min contact time at room temperature. The GK- U (VI) composite was characterized by FT-IR, zeta potential, TEM and SEM-EDAX. The Langmuir isotherm was found to be 487 mg of U (VI) g(-1) of GK. The adsorption capacity and (%) of U (VI) was found to be 490 ± 5.4 mg g(-1) and 98.5%. Moreover adsorption of U (VI) by GK was not influenced by other cations present in the simulated effluents. The adsorbed U (VI) was efficiently stripped from composite using 1 M HCl. Copyright © 2015 Elsevier Ltd. All rights reserved.

Structure and function of subsurface microbial communities affecting radionuclide transport and bioimmobilization

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

Kostka, Joel E.; Prakash, Om; Green, Stefan J.

2012-05-01

Our objectives were to: 1) isolate and characterize novel anaerobic prokaryotes from subsurface environments exposed to high levels of mixed contaminants (U(VI), nitrate, sulfate), 2) elucidate the diversity and distribution of metabolically active metal- and nitrate-reducing prokaryotes in subsurface sediments, and 3) determine the biotic and abiotic mechanisms linking electron transport processes (nitrate, Fe(III), and sulfate reduction) to radionuclide reduction and immobilization. Mechanisms of electron transport and U(VI) transformation were examined under near in situ conditions in sediment microcosms and in field investigations. Field sampling was conducted at the Oak Ridge Field Research Center (ORFRC), in Oak Ridge, Tennessee. Themore » ORFRC subsurface is exposed to mixed contamination predominated by uranium and nitrate. In short, we effectively addressed all 3 stated objectives of the project. In particular, we isolated and characterized a large number of novel anaerobes with a high bioremediation potential that can be used as model organisms, and we are now able to quantify the function of subsurface sedimentary microbial communities in situ using state-of-the-art gene expression methods (molecular proxies).« less

Bioremediation of petroleum-contaminated soil: A Review

NASA Astrophysics Data System (ADS)

Yuniati, M. D.

2018-02-01

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

Fate of Uranium During Transport Across the Groundwater-Surface Water Interface

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

Jaffe, Peter R.; Kaplan, Daniel I.

Discharge of contaminated groundwater to surface waters is of concern at many DOE facilities. For example, at F-Area and TNX-Area on the Savannah River Site, contaminated groundwater, including uranium, is already discharging into natural wetlands. It is at this interface where contaminants come into contact with the biosphere. These this research addressed a critical knowledge gap focusing on the geochemistry of uranium (or for that matter, any redox-active contaminant) in wetland systems. Understanding the interactions between hydrological, microbial, and chemical processes will make it possible to provide a more accurate conceptual and quantitative understanding of radionuclide fate and transport undermore » these unique conditions. Understanding these processes will permit better long-term management and the necessary technical justification for invoking Monitored Natural Attenuation of contaminated wetland areas. Specifically, this research did provide new insights on how plant-induced alterations to the sediment biogeochemical processes affect the key uranium reducing microorganisms, the uranium reduction, its spatial distribution, the speciation of the immobilized uranium, and its long-term stability. This was achieved by conducting laboratory mesocosm wetland experiments as well as field measurements at the SRNL. Results have shown that uranium can be immobilized in wetland systems. To a degree some of the soluble U(VI) was reduced to insoluble U(IV), but the majority of the immobilized U was incorporated into iron oxyhydroxides that precipitated onto the root surfaces of wetland plants. This U was immobilized mostly as U(VI). Because it was immobilized in its oxidized form, results showed that dry spells, resulting in the lowering of the water table and the exposure of the U to oxic conditions, did not result in U remobilization.« less

Application of Optical Imaging Techniques for Quantification of pH and O2 Dynamicsin Porous Media

NASA Astrophysics Data System (ADS)

Li, B.; Seliman, A. F.; Pales, A. R.; Liang, W.; Sams, A.; Darnault, C. J. G.; DeVol, T. A.

2016-12-01

Understanding the spatial and temporal distribution of physical and chemical parameters (e.g. pH, O2) is imperative to characterize the behavior of contaminants in a natural environment. The objectives of this research are to calibrate pH and O2 sensor foils, to develop a dual pH/O2 sensor foil, and to apply them into flow and transport experiments, in order to understand the physical and chemical parameters that control contaminant fate and transport in an unsaturated sandy porous medium. In addition, demonstration of a sensor foil that quantifies aqueous uranium concentration will be presented. Optical imaging techniques will be conducted with 2D tanks to investigate the influence of microbial exudates and plant roots on pH and O2 parameters and radionuclides transport. As a non-invasive method, the optical imaging technique utilizes optical chemical sensor films and either a digital camera or a spectrometer to capture the changes with high temporal and spatial resolutions. Sensor foils are made for different parameters by applying dyes to generate favorable fluorescence that is proportional to the parameter of interest. Preliminary results suggested that this method could detect pH ranging from 4.5 to 7.5. The result from uranium foil test with different concentrations in the range of 2 to 8 ppm indicated that a higher concentration of uranium resulted in a greater color intensity.

Bioremediation of waste under ocean acidification: Reviewing the role of Mytilus edulis.

PubMed

Broszeit, Stefanie; Hattam, Caroline; Beaumont, Nicola

2016-02-15

Waste bioremediation is a key regulating ecosystem service, removing wastes from ecosystems through storage, burial and recycling. The bivalve Mytilus edulis is an important contributor to this service, and is used in managing eutrophic waters. Studies show that they are affected by changes in pH due to ocean acidification, reducing their growth. This is forecasted to lead to reductions in M. edulis biomass of up to 50% by 2100. Growth reduction will negatively affect the filtering capacity of each individual, potentially leading to a decrease in bioremediation of waste. This paper critically reviews the current state of knowledge of bioremediation of waste carried out by M. edulis, and the current knowledge of the resultant effect of ocean acidification on this key service. We show that the effects of ocean acidification on waste bioremediation could be a major issue and pave the way for empirical studies of the topic. Copyright © 2016 Elsevier Ltd. All rights reserved.

Improvement of the Uranium Sequestration Ability of a Chlamydomonas sp. (ChlSP Strain) Isolated From Extreme Uranium Mine Tailings Through Selection for Potential Bioremediation Application.

PubMed

Baselga-Cervera, Beatriz; Romero-López, Julia; García-Balboa, Camino; Costas, Eduardo; López-Rodas, Victoria

2018-01-01

The extraction and processing of uranium (U) have polluted large areas worldwide, rendering anthropogenic extreme environments inhospitable to most species. Noticeably, these sites are of great interest for taxonomical and applied bioprospection of extremotolerant species successfully adapted to U tailings contamination. As an example, in this work we have studied a microalgae species that inhabits extreme U tailings ponds at the Saelices mining site (Salamanca, Spain), characterized as acidic (pH between 3 and 4), radioactive (around 4 μSv h -1 ) and contaminated with metals, mainly U (from 25 to 48 mg L -1 ) and zinc (from 17 to 87 mg L -1 ). After isolation of the extremotolerant ChlSP strain, morphological characterization and internal transcribed spacer (ITS)-5.8S gene sequences placed it in the Chlamydomonadaceae , but BLAST analyses identity values, against the nucleotide datasets at the NCBI database, were very low (<92%). We subjected the ChlSP strain to an artificial selection protocol to increase the U uptake and investigated its response to selection. The ancestral strain ChlSP showed a U-uptake capacity of ≈4.30 mg U g -1 of dry biomass (DB). However, the artificially selected strain ChlSG was able to take up a total of ≈6.34 mg U g -1 DB, close to the theoretical maximum response (≈7.9 mg U g -1 DB). The selected ChlSG strain showed two possible U-uptake mechanisms: the greatest proportion by biosorption onto cell walls (ca. 90%), and only a very small quantity, ~0.46 mg g -1 DB, irreversibly bound by bioaccumulation. Additionally, the kinetics of the U-uptake process were characterized during a microalgae growth curve; ChlSG cells removed close to 4 mg L -1 of U in 24 days. These findings open up promising prospects for sustainable management of U tailings waters based on newly evolved extremotolerants and outline the potential of artificial selection in the improvement of desired features in microalgae by experimental adaptation and selection.

Improvement of the Uranium Sequestration Ability of a Chlamydomonas sp. (ChlSP Strain) Isolated From Extreme Uranium Mine Tailings Through Selection for Potential Bioremediation Application

PubMed Central

Baselga-Cervera, Beatriz; Romero-López, Julia; García-Balboa, Camino; Costas, Eduardo; López-Rodas, Victoria

2018-01-01

The extraction and processing of uranium (U) have polluted large areas worldwide, rendering anthropogenic extreme environments inhospitable to most species. Noticeably, these sites are of great interest for taxonomical and applied bioprospection of extremotolerant species successfully adapted to U tailings contamination. As an example, in this work we have studied a microalgae species that inhabits extreme U tailings ponds at the Saelices mining site (Salamanca, Spain), characterized as acidic (pH between 3 and 4), radioactive (around 4 μSv h−1) and contaminated with metals, mainly U (from 25 to 48 mg L−1) and zinc (from 17 to 87 mg L−1). After isolation of the extremotolerant ChlSP strain, morphological characterization and internal transcribed spacer (ITS)-5.8S gene sequences placed it in the Chlamydomonadaceae, but BLAST analyses identity values, against the nucleotide datasets at the NCBI database, were very low (<92%). We subjected the ChlSP strain to an artificial selection protocol to increase the U uptake and investigated its response to selection. The ancestral strain ChlSP showed a U-uptake capacity of ≈4.30 mg U g−1 of dry biomass (DB). However, the artificially selected strain ChlSG was able to take up a total of ≈6.34 mg U g−1 DB, close to the theoretical maximum response (≈7.9 mg U g−1 DB). The selected ChlSG strain showed two possible U-uptake mechanisms: the greatest proportion by biosorption onto cell walls (ca. 90%), and only a very small quantity, ~0.46 mg g−1 DB, irreversibly bound by bioaccumulation. Additionally, the kinetics of the U-uptake process were characterized during a microalgae growth curve; ChlSG cells removed close to 4 mg L−1 of U in 24 days. These findings open up promising prospects for sustainable management of U tailings waters based on newly evolved extremotolerants and outline the potential of artificial selection in the improvement of desired features in microalgae by experimental adaptation and selection. PMID:29662476

Pair production in low-energy collisions of uranium nuclei beyond the monopole approximation

NASA Astrophysics Data System (ADS)

Maltsev, I. A.; Shabaev, V. M.; Tupitsyn, I. I.; Kozhedub, Y. S.; Plunien, G.; Stöhlker, Th.

2017-10-01

A method for calculation of electron-positron pair production in low-energy heavy-ion collisions beyond the monopole approximation is presented. The method is based on the numerical solving of the time-dependent Dirac equation with the full two-center potential. The one-electron wave functions are expanded in the finite basis set constructed on the two-dimensional spatial grid. Employing the developed approach the probabilities of bound-free pair production are calculated for collisions of bare uranium nuclei at the energy near the Coulomb barrier. The obtained results are compared with the corresponding values calculated in the monopole approximation.

Clean up fly ash from coal burning plants by new isolated fungi Fusarium oxysporum and Penicillium glabrum.

PubMed

Ertit Taştan, Burcu

2017-09-15

In Turkey approximately 45 million tons of coals are burned in a year and 19.3 million tons of fly ash have emerged. The bioremediation of heavy metals or different elements from fly ash makes them bio-available. However, in previous studies, requiring of long operational time and failing to show tolerance to high pulp densities of fly ash of selected fungal species makes them impractical. In this work, bioremediation of fly ash by new isolated fungi Fusarium oxysporum and Penicillium glabrum were investigated in one step and two step bioremediation process. Ca, Si, Fe and S were found to be considerable amount in studied fly ashes by ED-XRF element analysis. The bioremediation yields of Mo (100%), S (64.36%) Ni (50%) and Cu (33.33%) by F. oxysporum were high. The remediated elements by P. glabrum in fly ash were Mo (100%), S (57.43%), Ni (25%), Si (24.66%), V (12.5%), Ti (5%) and Sr (3.2%). The isolation of high fly ash resistant fungi and reduction of the bioremediation time will allow the practical applications of the bioremediation technology when it is scaled up. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bacterial community shift and hydrocarbon transformation during bioremediation of short-term petroleum-contaminated soil.

PubMed

Wu, Manli; Ye, Xiqiong; Chen, Kaili; Li, Wei; Yuan, Jing; Jiang, Xin

2017-04-01

A laboratory study was conducted to evaluate the impact of bioaugmentation plus biostimulation (BR, added both nutrients and bacterial consortia), and natural attenuation (NA) on hydrocarbon degradation efficiency and microflora characterization during remediation of a freshly contaminated soil. After 112 days of remediation, the initial level of total petroleum hydrocarbon (TPH) (61,000 mg/kg soil) was reduced by 4.5% and 5.0% in the NA and BR treatments, respectively. Bioremediation did not significantly enhance TPH biodegradation compared to natural attenuation. The degradation of the aliphatic fraction was the most active with the degradation rate of 30.3 and 28.7 mg/kg/day by the NA and BR treatments, respectively. Soil microbial activities and counts in soil were generally greater for bioremediation than for natural attenuation. MiSeq sequencing indicated that the diversity and structure of microbial communities were affected greatly by bioremediation. In response to bioremediation treatment, Promicromonospora, Pseudomonas, Microcella, Mycobacterium, Alkanibacter, and Altererythrobacter became dominant genera in the soil. The result indicated that combining bioaugmentation with biostimulation did not improve TPH degradation, but soil microbial activities and structure of microbial communities are sensitive to bioremediation in short-term and heavily oil-contaminated soil. Copyright © 2017 Elsevier Ltd. All rights reserved.

Implications of Bioremediation of Polycyclic Aromatic Hydrocarbon-Contaminated Soils for Human Health and Cancer Risk.

PubMed

Davie-Martin, Cleo L; Stratton, Kelly G; Teeguarden, Justin G; Waters, Katrina M; Simonich, Staci L Massey

2017-09-05

Bioremediation uses soil microorganisms to degrade polycyclic aromatic hydrocarbons (PAHs) into less toxic compounds and can be performed in situ, without the need for expensive infrastructure or amendments. This review provides insights into the cancer risks associated with PAH-contaminated soils and places bioremediation outcomes in a context relevant to human health. We evaluated which bioremediation strategies were most effective for degrading PAHs and estimated the cancer risks associated with PAH-contaminated soils. Cancer risk was statistically reduced in 89% of treated soils following bioremediation, with a mean degradation of 44% across the B2 group PAHs. However, all 180 treated soils had postbioremediation cancer risk values that exceeded the U.S. Environmental Protection Agency (USEPA) health-based acceptable risk level (by at least a factor of 2), with 32% of treated soils exceeding recommended levels by greater than 2 orders of magnitude. Composting treatments were most effective at biodegrading PAHs in soils (70% average reduction compared with 28-53% for the other treatment types), which was likely due to the combined influence of the rich source of nutrients and microflora introduced with organic compost amendments. Ultimately, bioremediation strategies, in the studies reviewed, were unable to successfully remove carcinogenic PAHs from contaminated soils to concentrations below the target cancer risk levels recommended by the USEPA.

Microarray and Real-Time PCR Analyses of the Responses of High-Arctic Soil Bacteria to Hydrocarbon Pollution and Bioremediation Treatments▿

PubMed Central

Yergeau, Etienne; Arbour, Mélanie; Brousseau, Roland; Juck, David; Lawrence, John R.; Masson, Luke; Whyte, Lyle G.; Greer, Charles W.

2009-01-01

High-Arctic soils have low nutrient availability, low moisture content, and very low temperatures and, as such, they pose a particular problem in terms of hydrocarbon bioremediation. An in-depth knowledge of the microbiology involved in this process is likely to be crucial to understand and optimize the factors most influencing bioremediation. Here, we compared two distinct large-scale field bioremediation experiments, located at the Canadian high-Arctic stations of Alert (ex situ approach) and Eureka (in situ approach). Bacterial community structure and function were assessed using microarrays targeting the 16S rRNA genes of bacteria found in cold environments and hydrocarbon degradation genes as well as quantitative reverse transcriptase PCR targeting key functional genes. The results indicated a large difference between sampling sites in terms of both soil microbiology and decontamination rates. A rapid reorganization of the bacterial community structure and functional potential as well as rapid increases in the expression of alkane monooxygenases and polyaromatic hydrocarbon-ring-hydroxylating dioxygenases were observed 1 month after the bioremediation treatment commenced in the Alert soils. In contrast, no clear changes in community structure were observed in Eureka soils, while key gene expression increased after a relatively long lag period (1 year). Such discrepancies are likely caused by differences in bioremediation treatments (i.e., ex situ versus in situ), weathering of the hydrocarbons, indigenous microbial communities, and environmental factors such as soil humidity and temperature. In addition, this study demonstrates the value of molecular tools for the monitoring of polar bacteria and their associated functions during bioremediation. PMID:19684169

Control of petroleum-hydrocarbon contaminated groundwater by intrinsic and enhanced bioremediation.

PubMed

Chen, Ku-Fan; Kao, Chih-Ming; Chen, Chiu-Wen; Surampalli, Rao Y; Lee, Mu-Sheng

2010-01-01

In the first phase of this study, the effectiveness of intrinsic bioremediation on the containment of petroleum hydrocarbons was evaluated at a gasoline spill site. Evidences of the occurrence of intrinsic bioremediation within the BTEX (benzene, toluene, ethylbenzene, and xylenes) plume included (1) decreased BTEX concentrations; (2) depletion of dissolved oxygen (DO), nitrate, and sulfate; (3) production of dissolved ferrous iron, methane, and CO2; (4) deceased pH and redox potential; and (5) increased methanogens, total heterotrophs, and total anaerobes, especially within the highly contaminated areas. In the second phase of this study, enhanced aerobic bioremediation process was applied at site to enhance the BTEX decay rates. Air was injected into the subsurface near the mid-plume area to biostimulate the naturally occurring microorganisms for BTEX biodegradation. Field results showed that enhanced bioremediation process caused the change of BTEX removal mechanisms from anaerobic biodegradation inside the plume to aerobic biodegradation. This variation could be confirmed by the following field observations inside the plume due to the enhanced aerobic bioremediation process: (1) increased in DO, CO2, redox potential, nitrate, and sulfate, (2) decreased in dissolved ferrous iron, sulfide, and methane, (3) increased total heterotrophs and decreased total anaerobes. Field results also showed that the percentage of total BTEX removal increased from 92% to 99%, and the calculated total BTEX first-order natural attenuation rates increased from 0.0092% to 0.0188% per day, respectively, after the application of enhanced bioremediation system from the spill area to the downgradient area (located approximately 300 m from the source area).

Implementation of Complex Biological Logic Circuits Using Spatially Distributed Multicellular Consortia

PubMed Central

Urrios, Arturo; de Nadal, Eulàlia; Solé, Ricard; Posas, Francesc

2016-01-01

Engineered synthetic biological devices have been designed to perform a variety of functions from sensing molecules and bioremediation to energy production and biomedicine. Notwithstanding, a major limitation of in vivo circuit implementation is the constraint associated to the use of standard methodologies for circuit design. Thus, future success of these devices depends on obtaining circuits with scalable complexity and reusable parts. Here we show how to build complex computational devices using multicellular consortia and space as key computational elements. This spatial modular design grants scalability since its general architecture is independent of the circuit’s complexity, minimizes wiring requirements and allows component reusability with minimal genetic engineering. The potential use of this approach is demonstrated by implementation of complex logical functions with up to six inputs, thus demonstrating the scalability and flexibility of this method. The potential implications of our results are outlined. PMID:26829588

Bioremediation of petroleum hydrocarbon-contaminated ground water: The perspectives of history and hydrology

USGS Publications Warehouse

Chapelle, F.H.

1999-01-01

Bioremediation, the use of microbial degradation processes to detoxify environmental contamination, was first applied to petroleum hydrocarbon-contaminated ground water systems in the early 1970s. Since that time, these technologies have evolved in some ways that were clearly anticipated early investigators, and in other ways that were not foreseen. The expectation that adding oxidants and nutrients to contaminated aquifers would enhance biodegradation, for example, has been born out subsequent experience. Many of the technologies now in common use such as air sparging, hydrogen peroxide addition, nitrate addition, and bioslurping, are conceptually similar to the first bioremediation systems put into operation. More unexpected, however, were the considerable technical problems associated with delivering oxidants and nutrients to heterogeneous ground water systems. Experience has shown that the success of engineered bioremediation systems depends largely on how effectively directions and rates of ground water flow can be controlled, and thus how efficiently oxidants and nutrients can be delivered to contaminated aquifer sediments. The early expectation that injecting laboratory-selected or genetically engineered cultures of hydrocarbon-degrading bacteria into aquifers would be a useful bioremediation technology has not been born out subsequent experience. Rather, it appears that petroleum hydrocarbon-degrading bacteria are ubiquitous in ground water systems and that bacterial addition is usually unnecessary. Perhaps the technology that was least anticipated early investigators was the development of intrinsic bioremediation. Experience has shown that natural attenuation mechanisms - biodegradation, dilution, and sorption - limit the migration of contaminants to some degree in all ground water systems. Intrinsic bioremediation is the deliberate use of natural attenuation processes to treat contaminated ground water to specified concentration levels at predetermined points in the aquifer. In current practice, intrinsic bioremediation of petroleum hydrocarbons requires a systematic assessment to show that ambient natural attenuation mechanisms are efficient enough to meet regulatory requirements and a monitoring program to verify that performance requirements are met in the future.

Mass Transfer Limited Enhanced Bioremediation at Dnapl Source Zones: a Numerical Study

NASA Astrophysics Data System (ADS)

Kokkinaki, A.; Sleep, B. E.

2011-12-01

The success of enhanced bioremediation of dense non-aqueous phase liquids (DNAPLs) relies on accelerating contaminant mass transfer from the organic to the aqueous phase, thus enhancing the depletion of DNAPL source zones compared to natural dissolution. This is achieved by promoting biological activity that reduces the contaminant's aqueous phase concentration. Although laboratory studies have demonstrated that high reaction rates are attainable by specialized microbial cultures in DNAPL source zones, field applications of the technology report lower reaction rates and prolonged remediation times. One possible explanation for this phenomenon is that the reaction rates are limited by the rate at which the contaminant partitions from the DNAPL to the aqueous phase. In such cases, slow mass transfer to the aqueous phase reduces the bioavailability of the contaminant and consequently decreases the potential source zone depletion enhancement. In this work, the effect of rate limited mass transfer on bio-enhanced dissolution of DNAPL chlorinated ethenes is investigated through a numerical study. A multi-phase, multi-component groundwater transport model is employed to simulate DNAPL mass depletion for a range of source zone scenarios. Rate limited mass transfer is modeled by a linear driving force model, employing a thermodynamic approach for the calculation of the DNAPL - water interfacial area. Metabolic reductive dechlorination is modeled by Monod kinetics, considering microbial growth and self-inhibition. The model was utilized to identify conditions in which mass transfer, rather than reaction, is the limiting process, as indicated by the bioavailability number. In such cases, reaction is slower than expected, and further increase in the reaction rate does not enhance mass depletion. Mass transfer rate limitations were shown to affect both dechlorination and microbial growth kinetics. The complex dynamics between mass transfer, DNAPL transport and distribution, and dechlorination kinetics were reflected in a transient, spatially heterogeneous bioavailability number and dissolution enhancement. In agreement with the literature, source zone architecture largely determined the impact of mass transfer on potential dissolution enhancement, with bioavailability decreasing the most at high ganglia to pool ratios. The results of this study suggest that if mass transfer rate limitations are not considered in designing bioremediation applications at DNAPL source zones, the enhancement of DNAPL depletion and the overall effectiveness of enhanced bioremediation may be significantly overestimated.

Bioremediation and phytoremediation: Chlorinated and recalcitrant compounds

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

NONE

1998-12-31

Bioremediation and phytoremediation have progressed, especially with regard to the treatment of hydrocarbon-contaminated sites. Sites contaminated with chlorinated and recalcitrant compounds have proven more resistant to these approaches, but exciting progress is being made both in the laboratory and in the field. This book brings together the latest breakthrough thinking and results in bioremediation, with chapters on cometabolic processes, aerobic and anaerobic mechanisms, biological reductive dechlorination processes, bioaugmentation, biomonitoring, and phytoremediation of recalcitrant organic compounds.

Microbial reductive dehalogenation of vinyl chloride

DOEpatents

Spormann, Alfred M [Stanford, CA; Muller, Jochen A [Baltimore, MD; Rosner, Bettina M [Berlin, DE; Von Abendroth, Gregory [Nannhein, DE; Meshulam-Simon, Galit [Los Altos, CA; McCarty, Perry L [Stanford, CA

2011-11-22

Compositions and methods are provided that relate to the bioremediation of chlorinated ethenes, particularly the bioremediation of vinyl chloride by Dehalococcoides-like organisms. An isolated strain of bacteria, Dehalococcoides sp. strain VS, that metabolizes vinyl chloride is provided; the genetic sequence of the enzyme responsible for vinyl chloride dehalogenation; methods of assessing the capability of endogenous organisms at an environmental site to metabolize vinyl chloride; and a method of using the strains of the invention for bioremediation.

Demonstration of a Fractured Rock Geophysical Toolbox (FRGT) for Characterization and Monitoring of DNAPL Biodegradation in Fractured Rock Aquifers

DTIC Science & Technology

2015-09-29

initial amendment emplacement rather than longterm monitoring of bioremediation . A number of specific developments of cross- borehole ERT imaging...These substrates are commonly used for enhanced bioremediation and are readily available. For time-lapse ERT imaging, it is important that there is a...to remediation professionals and regulators. This includes the following LinkedIn groups: Bioremediation ; Contaminant Transport in Fractured Bedrock

Microbial reductive dehalogenation of vinyl chloride

DOEpatents

Spormann, Alfred M [Stanford, CA; Muller, Jochen A [Baltimore, MD; Rosner, Bettina M [Berlin, DE; Von Abendroth, Gregory [Mannheim, DE; Meshulam-Simon, Galit [Los Angeles, CA; McCarty, Perry L [Stanford, CA

2014-02-11

Compositions and methods are provided that relate to the bioremediation of chlorinated ethenes, particularly the bioremediation of vinyl chloride by Dehalococcoides-like organisms. An isolated strain of bacteria, Dehalococcoides sp. strain VS, that metabolizes vinyl chloride is provided; the genetic sequence of the enzyme responsible for vinyl chloride dehalogenation; methods of assessing the capability of endogenous organisms at an environmental site to metabolize vinyl chloride; and a method of using the strains of the invention for bioremediation.

Developments in Bioremediation of Soils and Sediments Pollutedwith Metals and Radionuclides: 2. Field Research on Bioremediation of Metals and Radionuclides

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

Hazen, Terry C.; Tabak, Henry H.

2007-03-15

Bioremediation of metals and radionuclides has had manyfield tests, demonstrations, and full-scale implementations in recentyears. Field research in this area has occurred for many different metalsand radionuclides using a wide array of strategies. These strategies canbe generally characterized in six major categories: biotransformation,bioaccumulation/bisorption, biodegradation of chelators, volatilization,treatment trains, and natural attenuation. For all field applicationsthere are a number of critical biogeochemical issues that most beaddressed for the successful field application. Monitoring andcharacterization parameters that are enabling to bioremediation of metalsand radionuclides are presented here. For each of the strategies a casestudy is presented to demonstrate a field application that usesmore » thisstrategy.« less

Factoring uncertainty into restoration modeling of in-situ leach uranium mines

USGS Publications Warehouse

Johnson, Raymond H.; Friedel, Michael J.

2009-01-01

Postmining restoration is one of the greatest concerns for uranium in-situ leach (ISL) mining operations. The ISL-affected aquifer needs to be returned to conditions specified in the mining permit (either premining or other specified conditions). When uranium ISL operations are completed, postmining restoration is usually achieved by injecting reducing agents into the mined zone. The objective of this process is to restore the aquifer to premining conditions by reducing the solubility of uranium and other metals in the ground water. Reactive transport modeling is a potentially useful method for simulating the effectiveness of proposed restoration techniques. While reactive transport models can be useful, they are a simplification of reality that introduces uncertainty through the model conceptualization, parameterization, and calibration processes. For this reason, quantifying the uncertainty in simulated temporal and spatial hydrogeochemistry is important for postremedial risk evaluation of metal concentrations and mobility. Quantifying the range of uncertainty in key predictions (such as uranium concentrations at a specific location) can be achieved using forward Monte Carlo or other inverse modeling techniques (trial-and-error parameter sensitivity, calibration constrained Monte Carlo). These techniques provide simulated values of metal concentrations at specified locations that can be presented as nonlinear uncertainty limits or probability density functions. Decisionmakers can use these results to better evaluate environmental risk as future metal concentrations with a limited range of possibilities, based on a scientific evaluation of uncertainty.

Tn-seq of Caulobacter crescentus under uranium stress reveals genes essential for detoxification and stress tolerance

DOE PAGES

Yung, Mimi C.; Park, Dan M.; Overton, K. Wesley; ...

2015-07-20

Ubiquitous aquatic bacterium Caulobacter crescentus is highly resistant to uranium (U) and facilitates U biomineralization and thus holds promise as an agent of U bioremediation. In order to gain an understanding of how C. crescentus tolerates U, we employed transposon (Tn) mutagenesis paired with deep sequencing (Tn-seq) in a global screen for genomic elements required for U resistance. Of the 3,879 annotated genes in the C. crescentus genome, 37 were found to be specifically associated with fitness under U stress, 15 of which were subsequently tested through mutational analysis. Systematic deletion analysis revealed that mutants lacking outer membrane transporters (rsaFamore » and rsaFb), a stress-responsive transcription factor (cztR), or a ppGpp synthetase/hydrolase (spoT) exhibited a significantly lower survival rate under U stress. RsaFa and RsaFb, which are homologues of TolC in Escherichia coli, have previously been shown to mediate S-layer export. Transcriptional analysis revealed upregulation of rsaF a and rsaF b by 4- and 10-fold, respectively, in the presence of U. We additionally show that rsaFa mutants accumulated higher levels of U than the wild type, with no significant increase in oxidative stress levels. These results suggest a function for RsaF a and RsaF b in U efflux and/or maintenance of membrane integrity during U stress. In addition, we present data implicating CztR and SpoT in resistance to U stress. Together, our findings reveal novel gene targets that are key to understanding the molecular mechanisms of U resistance in C. crescentus.« less

Preliminary report on the Comet area, Jefferson County, Montana

USGS Publications Warehouse

Becraft, George Earle

1952-01-01

Several radioactivity anomalies and a few specimens of sooty pitchblende and other uranium minerals have been found on the mine dumps of formerly productive base-and precious-metal mines along the Comet-Gray Eagle shear zone in the Comet area in southwestern Montana. The shear zone is from 50 to 200 feet wide and has been traced for at least 5 1/2 miles. It trends N. 80° W. across the northern part of the area and cuts the quartz monzonitic rocks of the Boulder batholith and younger silicic intrusive rocks, as well as the pre-batholitic volcanic rocks, and is in turn cut by dacite and andesite dikes. The youngest period of mineralization is represented by chalcedonic vein zones comprising one or more discontinuous stringers and veins of cryptocrystalline silica in silicified quartz monzonite and in alaskite that has not been appreciably silicified. In some places these zones contain no distinct chalcedonic veins, but are represented only by silicified quartz monzonite. These zones locally contain uranium in association with very small amounts of the following minerals: pyrite, galena, ruby silver, argentite, native silver, molybdenite, chalcopyrite, arsenopyrite, and barite. At the Free Enterprise mine, uranium has been produced from a narrow chalcedonic vein that contains disseminated secondary uranium minerals and local small pods of pitchblende and from disseminated secondary uranium minerals in the adjacent quartz monzonite. Undiscovered commercial deposits of uranium ore may occur spatially associated with the base-and precious-metal deposits along the Comet-Gray Eagle shear zone, and chalcedonic vein zones similar to the Free Enterprise.

Synergistic effects of bioremediation and electrokinetics in the remediation of petroleum-contaminated soil.

PubMed

Guo, Shuhai; Fan, Ruijuan; Li, Tingting; Hartog, Niels; Li, Fengmei; Yang, Xuelian

2014-08-01

The present study evaluated the coupling interactions between bioremediation (BIO) and electrokinetics (EK) in the remediation of total petroleum hydrocarbons (TPH) by using bio-electrokinetics (BIO-EK) with a rotatory 2-D electric field. The results demonstrated an obvious positive correlation between the degradation extents of TPH and electric intensity both in the EK and BIO-EK tests. The use of BIO-EK showed a significant improvement in degradation of TPH as compared to BIO or EK alone. The actual degradation curve in BIO-EK tests fitted well with the simulated curve obtained by combining the degradation curves in BIO- and EK-only tests during the first 60 d, indicating a superimposed effect of biological degradation and electrochemical stimulation. The synergistic effect was particularly expressed during the later phase of the experiment, concurrent with changes in the microbial community structure. The community composition changed mainly according to the duration of the electric field, leading to a reduction in diversity. No significant spatial shifts in microbial community composition and bacterial numbers were detected among different sampling positions. Soil pH was uniform during the experimental process, soil temperature showed no variations between the soil chambers with and without an electric field. Copyright © 2014 Elsevier Ltd. All rights reserved.

Engineered and subsequent intrinsic in situ bioremediation of a diesel fuel contaminated aquifer

NASA Astrophysics Data System (ADS)

Hunkeler, Daniel; Höhener, Patrick; Zeyer, Josef

2002-12-01

A diesel fuel contaminated aquifer in Menziken, Switzerland was treated for 4.5 years by injecting aerated groundwater, supplemented with KNO 3 and NH 4H 2PO 4 to stimulate indigenous populations of petroleum hydrocarbon (PHC) degrading microorganisms. After dissolved PHC concentrations had stabilized at a low level, engineered in situ bioremediation was terminated. The main objective of this study was to evaluate the efficacy of intrinsic in situ bioremediation as a follow-up measure to remove PHC remaining in the aquifer after terminating engineered in situ bioremediation. In the first 7 months of intrinsic in situ bioremediation, redox conditions in the source area became more reducing as indicated by lower concentrations of SO 42- and higher concentrations of Fe(II) and CH 4. In the core of the source area, strongly reducing conditions prevailed during the remaining study period (3 years) and dissolved PHC concentrations were higher than during engineered in situ bioremediation. This suggests that biodegradation in the core zone was limited by the availability of oxidants. In lateral zones of the source area, however, gradually more oxidized conditions were reestablished again, suggesting that PHC availability increasingly limited biodegradation. The total DIC production rate in the aquifer decreased within 2 years to about 25% of that during engineered in situ bioremediation and remained at that level. Stable carbon isotope analysis confirmed that the produced DIC mainly originated from PHC mineralization. The total rate of DIC and CH 4 production in the source area was more than 300 times larger than the rate of PHC elution. This indicates that biodegradation coupled to consumption of naturally occurring oxidants was an important process for removal of PHC which remained in the aquifer after terminating engineered measures.

Bioremediation of Petroleum Hydrocarbon Contaminated Sites

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

Fallgren, Paul

Bioremediation has been widely applied in the restoration of petroleum hydrocarbon-contaminated. Parameters that may affect the rate and efficiency of biodegradation include temperature, moisture, salinity, nutrient availability, microbial species, and type and concentration of contaminants. Other factors can also affect the success of the bioremediation treatment of contaminants, such as climatic conditions, soil type, soil permeability, contaminant distribution and concentration, and drainage. Western Research Institute in conjunction with TechLink Environmental, Inc. and the U.S. Department of Energy conducted laboratory studies to evaluate major parameters that contribute to the bioremediation of petroleum-contaminated drill cuttings using land farming and to develop amore » biotreatment cell to expedite biodegradation of hydrocarbons. Physical characteristics such as soil texture, hydraulic conductivity, and water retention were determined for the petroleum hydrocarbon contaminated soil. Soil texture was determined to be loamy sand to sand, and high hydraulic conductivity and low water retention was observed. Temperature appeared to have the greatest influence on biodegradation rates where high temperatures (>50 C) favored biodegradation. High nitrogen content in the form of ammonium enhanced biodegradation as well did the presence of water near field water holding capacity. Urea was not a good source of nitrogen and has detrimental effects for bioremediation for this site soil. Artificial sea water had little effect on biodegradation rates, but biodegradation rates decreased after increasing the concentrations of salts. Biotreatment cell (biocell) tests demonstrated hydrocarbon biodegradation can be enhanced substantially when utilizing a leachate recirculation design where a 72% reduction of hydrocarbon concentration was observed with a 72-h period at a treatment temperature of 50 C. Overall, this study demonstrates the investigation of the effects of environmental parameters on bioremediation is important in designing a bioremediation system to reduce petroleum hydrocarbon concentrations in impacted soils.« less

Investigating the biogeochemical interactions involved in simultaneous TCE and Arsenic in situ bioremediation

NASA Astrophysics Data System (ADS)

Cook, E.; Troyer, E.; Keren, R.; Liu, T.; Alvarez-Cohen, L.

2016-12-01

The in situ bioremediation of contaminated sediment and groundwater is often focused on one toxin, even though many of these sites contain multiple contaminants. This reductionist approach neglects how other toxins may affect the biological and chemical conditions, or vice versa. Therefore, it is of high value to investigate the concurrent bioremediation of multiple contaminants while studying the microbial activities affected by biogeochemical factors. A prevalent example is the bioremediation of arsenic at sites co-contaminated with trichloroethene (TCE). The conditions used to promote a microbial community to dechlorinate TCE often has the adverse effect of inducing the release of previously sequestered arsenic. The overarching goal of our study is to simultaneously evaluate the bioremediation of arsenic and TCE. Although TCE bioremediation is a well-understood process, there is still a lack of thorough understanding of the conditions necessary for effective and stable arsenic bioremediation in the presence of TCE. The objective of this study is to promote bacterial activity that stimulates the precipitation of stable arsenic-bearing minerals while providing anaerobic, non-extreme conditions necessary for TCE dechlorination. To that end, endemic microbial communities were examined under various conditions to attempt successful sequestration of arsenic in addition to complete TCE dechlorination. Tested conditions included variations of substrates, carbon source, arsenate and sulfate concentrations, and the presence or absence of TCE. Initial arsenic-reducing enrichments were unable to achieve TCE dechlorination, probably due to low abundance of dechlorinating bacteria in the culture. However, favorable conditions for arsenic precipitation in the presence of TCE were eventually discovered. This study will contribute to the understanding of the key species in arsenic cycling, how they are affected by various concentrations of TCE, and how they interact with the key species in a dechlorinating community.

A miniaturized bismuth-based sensor to evaluate the marine organism Styela plicata bioremediation capacity toward heavy metal polluted seawater.

PubMed

Colozza, Noemi; Gravina, Maria Flavia; Amendola, Luca; Rosati, Modesto; Akretche, Djamal Eddine; Moscone, Danila; Arduini, Fabiana

2017-04-15

Cadmium and lead are highly toxic heavy metals which cause a severe worldwide pollution. In addition to the toxic effect produced by the direct exposure, they can be bioconcentrated and accumulated in living organisms, including humans. Herein, a miniaturized and disposable electrochemical sensor was improved for the simultaneous detection of cadmium and lead ions to study the bioremediation of polluted seawater in presence of the filter-feeding marine organism Styela plicata. A screen-printed electrode modified in situ with a bismuth film was selected using the anodic stripping analysis as detection technique. This sensor was coupled with a portable potentiostat and the detection of cadmium and lead ions was carried out by Square Wave Anodic Stripping Voltammetry, allowing the simultaneous detection of both heavy metals at ppb level (LOD=0.3ppb for lead, 1.5ppb for cadmium). This analytical tool was then applied to assess the bioremediation capacity of S. plicata through a bioremediation experiment, in which the organism has been exposed to seawater artificially polluted with 1000ppb of Cd 2+ and Pb 2+ . The matrix effect of both seawater and acid digested biological samples was evaluated. A bioconcentration phenomenon was observed for both heavy metals through the analysis of S. plicata tissues. In details, Pb 2+ resulted to be about 2.5 times more bioconcentrated than Cd 2+ , giving an effective bioremediation level in seawater of 13% and 40% for Cd 2+ and Pb 2+ , respectively. Thus, our results demonstrate the capability of S. plicata to bioremediate Cd 2+ and Pb 2+ polluted seawater as well as the suitability of the electrochemical sensor for contaminated marine environment monitoring and bioremediation evaluation. Copyright © 2017 Elsevier B.V. All rights reserved.

Soil mesocosm studies on atrazine bioremediation.

PubMed

Sagarkar, Sneha; Nousiainen, Aura; Shaligram, Shraddha; Björklöf, Katarina; Lindström, Kristina; Jørgensen, Kirsten S; Kapley, Atya

2014-06-15

Accumulation of pesticides in the environment causes serious issues of contamination and toxicity. Bioremediation is an ecologically sound method to manage soil pollution, but the bottleneck here, is the successful scale-up of lab-scale experiments to field applications. This study demonstrates pilot-scale bioremediation in tropical soil using atrazine as model pollutant. Mimicking field conditions, three different bioremediation strategies for atrazine degradation were explored. 100 kg soil mesocosms were set-up, with or without atrazine application history. Natural attenuation and enhanced bioremediation were tested, where augmentation with an atrazine degrading consortium demonstrated best pollutant removal. 90% atrazine degradation was observed in six days in soil previously exposed to atrazine, while soil without history of atrazine use, needed 15 days to remove the same amount of amended atrazine. The bacterial consortium comprised of 3 novel bacterial strains with different genetic atrazine degrading potential. The progress of bioremediation was monitored by measuring the levels of atrazine and its intermediate, cyanuric acid. Genes from the atrazine degradation pathway, namely, atzA, atzB, atzD, trzN and trzD were quantified in all mesocosms for 60 days. The highest abundance of all target genes was observed on the 6th day of treatment. trzD was observed in the bioaugmented mesocosms only. The bacterial community profile in all mesocosms was monitored by LH-PCR over a period of two months. Results indicate that the communities changed rapidly after inoculation, but there was no drastic change in microbial community profile after 1 month. Results indicated that efficient bioremediation of atrazine using a microbial consortium could be successfully up-scaled to pilot scale. Copyright © 2014 Elsevier Ltd. All rights reserved.

Bioremediation: Hope/Hype for Environmental Cleanup (LBNL Summer Lecture Series)

ScienceCinema

Hazen, Terry [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). Ecology Dept.

2018-01-23

Summer Lecture Series 2007: Terry Hazen, Senior Staff Scientists and Head of the LBNL Ecology Department, discusses when it's best to resort to engineered bioremediation of contaminated sites, and when it's best to rely on natural attenuation. Recent advances have greatly broadened the potential applications for bioremediation. At the same time, scientists' knowledge of biogeochemical processes has advanced and they can better gauge how quickly and completely contaminants can be degraded without human intervention.

Bioremediation: Hope/Hype for Environmental Cleanup (LBNL Summer Lecture Series)

ScienceCinema

Hazen, Terry [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Ecology Dept.

2018-05-04

Summer Lecture Series 2007: Terry Hazen, Senior Staff Scientists and Head of the LBNL Ecology Department, discusses when it's best to resort to engineered bioremediation of contaminated sites, and when it's best to rely on natural attenuation. Recent advances have greatly broadened the potential applications for bioremediation. At the same time, scientists' knowledge of biogeochemical processes has advanced and they can better gauge how quickly and completely contaminants can be degraded without human intervention.

Electrokinetic-enhanced bioremediation of organic contaminants: a review of processes and environmental applications.

PubMed

Gill, R T; Harbottle, M J; Smith, J W N; Thornton, S F

2014-07-01

There is current interest in finding sustainable remediation technologies for the removal of contaminants from soil and groundwater. This review focuses on the combination of electrokinetics, the use of an electric potential to move organic and inorganic compounds, or charged particles/organisms in the subsurface independent of hydraulic conductivity; and bioremediation, the destruction of organic contaminants or attenuation of inorganic compounds by the activity of microorganisms in situ or ex situ. The objective of the review is to examine the state of knowledge on electrokinetic bioremediation and critically evaluate factors which affect the up-scaling of laboratory and bench-scale research to field-scale application. It discusses the mechanisms of electrokinetic bioremediation in the subsurface environment at different micro and macroscales, the influence of environmental processes on electrokinetic phenomena and the design options available for application to the field scale. The review also presents results from a modelling exercise to illustrate the effectiveness of electrokinetics on the supply electron acceptors to a plume scale scenario where these are limiting. Current research needs include analysis of electrokinetic bioremediation in more representative environmental settings, such as those in physically heterogeneous systems in order to gain a greater understanding of the controlling mechanisms on both electrokinetics and bioremediation in those scenarios. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Introduction to In Situ Bioremediation of Groundwater

EPA Pesticide Factsheets

Bioremediation is an engineered technology that modifies environmental conditions (physical, chemical, biochemical, or microbiological) to encourage microorganisms to destroy or detoxify organic and inorganic contaminants in the environment.

Extremophilic Microfactories: Applications in Metal and Radionuclide Bioremediation.

PubMed

Marques, Catarina R

2018-01-01

Metals and radionuclides (M&Rs) are a worldwide concern claiming for resilient, efficient, and sustainable clean-up measures aligned with environmental protection goals and global change constraints. The unique defense mechanisms of extremophilic bacteria and archaea have been proving usefulness towards M&Rs bioremediation. Hence, extremophiles can be viewed as microfactories capable of providing specific and controlled services (i.e., genetic/metabolic mechanisms) and/or products (e.g., biomolecules) for that purpose. However, the natural physiological plasticity of such extremophilic microfactories can be further explored to nourish different hallmarks of M&R bioremediation, which are scantly approached in the literature and were never integrated. Therefore, this review not only briefly describes major valuable extremophilic pathways for M&R bioremediation, as it highlights the advances, challenges and gaps from the interplay of 'omics' and biological engineering to improve extremophilic microfactories performance for M&R clean-up. Microfactories' potentialities are also envisaged to close the M&R bioremediation processes and shift the classical idea of never 'getting rid' of M&Rs into making them 'the belle of the ball' through bio-recycling and bio-recovering techniques.

[Effects and Biological Response on Bioremediation of Petroleum Contaminated Soil].

PubMed

Yang, Qian; Wu, Man-li; Nie, Mai-qian; Wang, Ting-ting; Zhang, Ming-hui

2015-05-01

Bioaugmentation and biostimulation were used to remediate petroleum-contaminated soil which were collected from Zichang city in North of Shaanxi. The optimal bioremediation method was obtained by determining the total petroleum hydrocarbon(TPH) using the infrared spectroscopy. During the bioremediation, number of degrading strains, TPH catabolic genes, and soil microbial community diversity were determined by Most Probable Number (MPN), polymerase chain reaction (PCR) combined agarose electrophoresis, and PCR-denaturing gradient electrophoresis (DGGE). The results in different treatments showed different biodegradation effects towards total petroleum hydrocarbon (TPH). Biostimulation by adding N and P to soils achieved the best degradation effects towards TPH, and the bioaugmentation was achieved by inoculating strain SZ-1 to soils. Further analysis indicated the positive correlation between catabolic genes and TPH removal efficiency. During the bioremediation, the number of TPH and alkanes degrading strains was higher than the number of aromatic degrading strains. The results of PCR-DGGE showed microbial inoculums could enhance microbial community functional diversity. These results contribute to understand the ecologically microbial effects during the bioremediation of petroleum-polluted soil.

BIOREMEDIATION TRAINING

EPA Science Inventory

Bioremediation encompasses a collection of technologies which use microbes to degrade or transform contaminants. Three technologies have an established track record of acceptable performance: aerobic bioventing for fuels; enhanced reductive dechlorination for chlorinated solvent...

Test plan for the soils facility demonstration: A petroleum contaminated soil bioremediation facility

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

Lombard, K.H.

1994-08-01

The objectives of this test plan are to show the value added by using bioremediation as an effective and environmentally sound method to remediate petroleum contaminated soils (PCS) by: demonstrating bioremediation as a permanent method for remediating soils contaminated with petroleum products; establishing the best operating conditions for maximizing bioremediation and minimizing volatilization for SRS PCS during different seasons; determining the minimum set of analyses and sampling frequency to allow efficient and cost-effective operation; determining best use of existing site equipment and personnel to optimize facility operations and conserve SRS resources; and as an ancillary objective, demonstrating and optimizing newmore » and innovative analytical techniques that will lower cost, decrease time, and decrease secondary waste streams for required PCS assays.« less

Superior cottonwood and eucalyptus clones for biomass production in wastewater biomass production in wastewater bioremediation systems

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

Rockwood, D.L.; Pisano, S.M.; McConnell, W.V.

1996-12-31

Fast-growing cottonwood and Eucalyptus species have wastewater bioremediation potential. To estimate genetic variation in cottonwood`s response to sewage effluent, 10 clones were planted at Tallahassee in April 1992. Progenies and/or clones of E. Ampligolia (EA). E. Camaldulensis (EC), and E. Grandis (EG) were planted in a dry stormwater retention/bioremediation pond constructed in June 1993 at Tampa. Genetic variability within cottonwood and Eucalyptus species was observed and should be utilized to optimize biomass production and nutrient uptake in wastewater bioremediation applications. On good sites with freeze risk in northern Florida, three cottonwood clones are particularly productive. While as many as fourmore » EC and EG clones are promising, one EG clone appears superior for stormwater remediation, systems in central Florida.« less

Bioremediation process on Brazil shoreline. Laboratory experiments.

PubMed

Rosa, Anabela P; Triguis, Jorge A

2007-11-01

Bioremediation technique can be considered a promising alternative to clean oil spills using microbial processes to reduce the concentration and/or the toxicity of pollutants. To understand the importance of this work we must know that there is only little research performed to date using bioremediation techniques to clean oil spills in tropical countries. So, the main objective of this work is to analyze the behavior of a laboratory's bioremediation test using nutrients on coastal sediments. The bioremediation process is followed through geochemical analysis during the tests. This organic material is analyzed by medium pressure liquid chromatography (MPLC), gas chromatography/flame ionization detection (GC/FID) and gas chromatography/ mass spectrometry. By microbial counting, the number of total bacteria and degrading bacteria is determined during the experiments, in order to confirm the effectiveness of the bioremediation process. The seawater obtained throughout the bioremediation process is analyzed for nutrients grade (phosphate and ammonium ions) and also for its toxicity (Microtox tests) due the presence of hydrocarbons and fertilizer. The results from the geochemical analyses of the oil show a relative decrease in the saturated hydrocarbon fraction that is compensated by a relative enrichment on polar compounds. It's confirmed by the fingerprint evaluation where it is possible to see a complete reduction of the normal alkanes followed by isoprenoids. Seawater analysis done by toxicity and nutrients analysis, such as microbial counting (total and degrading bacteria), confirm the fertilizer effectiveness during the bioremediation process. Results from simulating test using NPK, a low-price plant fertilizer, suggest that it's able to stimulate the degradation process. Results from medium pressure liquid chromatography (MPLC), done at two different depths (surface and subsurface), show different behavior during the biodegradation process where the later is seen to be more susceptible to microbial attack. Data from bioremediation unit shows a bigger reduction of the saturated fraction, followed by some smaller reduction of aromatic fractions, compensated by a relative increase from polar compounds (NSO). n-C17/pristane, n-C18/ fitane and pristane/fitane rates show constant values for the unity control, different from bioremediation samples which have a significant reduction, especially on subsurface areas, where a strong fall in the rates, seen to be reduced to zero over twenty days, had occurred during the first ten days. However, sample surfaces are reduced to zero in thirty days of experiments, proving that biodegradation is better on subsurfaces. Gaseous chromatography/mass spectrometry (CG/MS) analysis shows constant values to cyclic biomarker rates and aromatic compounds, suggesting that the biodegradation process is not strong enough to reduce these composites. Microbial analysis shows a reduction on heterotrophic (total bacteria) number from control unit, probably because the bacteria uses the spill oil like carbon source and energy. However, the number increases on bioremediation unit, because it uses NPK like a biostimulator. The hydrocarbonoclastic number isn't enough on the first moment, but it's detected after 30 days and quantified in all units, showing big values especially in bioremediation. Toxicity tests confirm that NPK fertilizer does not intoxicate the shoreline during the application of the bioremediation technique. Some nutrient concentration shows high values of ammonium and phosphate per bioremediation unit, reducing by the end of the experiment. Results reached the goal, finding a proper nutrient (NPK fertilizer) to stimulate the biodegradation process, growing bacteria responsible for reducing impact-contaminated coast ambient by oil spills. Chemical analysis of oil shows a reduction in the saturated fraction with a relative enrichment in polar composites (NSO) and the aromatic fraction from oil remaining constant. Subsurface samples show more biodegradation than surface samples, probably because the first one has higher humidity. Linear alcanes are more biodegraded than isoprenoids, confirming the biodegradation susceptibility order. Saturated cyclic biomarkers and aromatic compounds show constant behavior maybe because the nutrients or time was not enough for microorganismic attack. Fertilizer does not demonstrate any toxic effects in local biota so that it does not compromise the technique applicability and the environment is not saturated by nutrients during the simulation, especially since the coastal environment is an open system affected daily by tides. Therefore, bioremediation tests can be classified as moderate, reaching level 5 in the classification scale by Peters & Moldowan (1993). The use of marine environment by the petroleum industry on exploration, production and transportation operation, transform this oil to become the most important pollutant in the oceans. Bioremediation is an important technique used to clean spilled oil impacting on shorelines, accelerating the biodegradation process by using fertilizer growing the microorganisms responsible for decontaminating the environment. We recommend confirming the efficiency of NPK nutrient used on bioremediation simulating experiments on beaches, while monitoring the chemical changes long-term. NPK fertilizer can be used to stimulate the biodegradation process on shoreline impacted by spilled oil.

Radon-222 as a Natural Tracer for Monitoring the Remediation of NAPL Contamination in the Subsurface

DTIC Science & Technology

2006-11-06

cell. The test cell at the site also underwent active remediation using enhanced in situ bioremediation . The PCE released into the test cell was also...Figure 3.2 is a photo of the test cell used in the demonstration and the long-term monitoring locations during the bioremediation study. Injection wells...monitoring indicated that little change in radon occurred despite the application of the bioremediation process. This is in agreement with the PCE

A Semi-Quantitative Study of the Impact of Bacterial Pollutant Uptake Capability on Bioremediation in a Saturated Sand-Packed Two-Dimensional Microcosm: Experiments and Simulation

NASA Astrophysics Data System (ADS)

Zheng, S.; Ford, R.; Van den Berg, B.

2016-12-01

The transport of microorganisms through the saturated porous matrix of soil is critical to the success of bioremediation in polluted groundwater systems. Chemotaxis can direct the movement of microorganisms toward higher concentration of pollutants, which they chemically transform and use as carbon and energy sources, resulting in enhanced bioremediation efficiency. In addition to accessibility and degradation kinetics, bacterial uptake of the pollutants is a critical step in bioremediation. In order to study the impact of bacterial pollutant uptake capability on bioremediation, a two-dimensional microcosm packed with saturated sand was set up to mimic the natural groundwater system where mass transfer limitation poses a barrier (see the figure below). Toluene source was continuously injected into the microcosm from an injection port. Pseudomonas putida F1, either wild-type (WT) or genetic mutants (TodX knockout, TodX and CymD knockout) that exhibited impaired toluene uptake capability, were co-injected with a conservative tracer into the microcosm either above or below the toluene. After each run, samples were collected from a dozen effluent ports to determine the concentration profiles of the bacteria and tracers. Toluene serves as the only carbon source throughout the microcosm. So the percent recovery, which is the ratio of cells collected at the outlet over that at the inlet, can be used as the indicator for bioremediation efficiency. Comparisons were made between the WT and mutant strains, where PpF1 WT showed greater proliferation than the mutants. Comparisons for low and high toluene source concentrations showed that the PpF1 mutant strains exhibited a greater degree of growth inhibition than WT at higher toluene concentration. A mathematical model was applied to evaluate the impact of various parameters on toluene uptake illustrating that with reasonable parameter estimates, the bioremediation efficiency was more sensitive to proliferation than transport. The results show that in a two-dimensional microcosm mimicking features of the natural groundwater system, the toluene uptake capability of bacteria can be the "remediation-rate-liming" step, implying the potential of engineering bacteria for bioremediation efficiency enhancement.

Bioremediation of a diesel fuel contaminated aquifer: simulation studies in laboratory aquifer columns

NASA Astrophysics Data System (ADS)

Hess, A.; Höhener, P.; Hunkeler, D.; Zeyer, J.

1996-08-01

The in situ bioremediation of aquifers contaminated with petroleum hydrocarbons is commonly based on the infiltration of groundwater supplemented with oxidants (e.g., O 2, NO 3-) and nutrients (e.g., NH 4+, PO 43-). These additions stimulate the microbial activity in the aquifer and several field studies describing the resulting processes have been published. However, due to the heterogeneity of the subsurface and due to the limited number of observation wells usually available, these field data do not offer a sufficient spatial and temporal resolution. In this study, flow-through columns of 47-cm length equipped with 17 sampling ports were filled with homogeneously contaminated aquifer material from a diesel fuel contaminated in situ bioremediation site. The columns were operated over 96 days at 12°C with artificial groundwater supplemented with O 2, NO 3- and PO 43-. Concentration profiles of O 2, NO 3-, NO 2-, dissolved inorganic and organic carbon (DIC and DOC, respectively), protein, microbial cells and total residual hydrocarbons were measured. Within the first 12 cm, corresponding to a mean groundwater residence time of < 3.6 h, a steep O 2 decrease from 4.6 to < 0.3 mg l -1, denitrification, a production of DIC and DOC, high microbial cell numbers and a high removal of hydrocarbons were observed. Within a distance of 24 to 40.5 cm from the infiltration, O 2 was below 0.1 mg l -1 and a denitrifying activity was found. In the presence and in the absence of O 2, n-alkanes were preferentially degraded compared to branched alkanes. The results demonstrate that: (1) infiltration of aerobic groundwater into columns filled with aquifer material contaminated with hydrocarbons leads to a rapid depletion of O 2; (2) O 2 and NO 3- can serve as oxidants for the mineralization of hydrocarbons; and (3) the modelling of redox processes in aquifers has to consider denitrifying activity in presence of O 2.

Identifying and Further Understanding the Role of Bacteria and Archaea in a Basic Mine Drainage Remediation Site in Tanoma, PA

NASA Astrophysics Data System (ADS)

Sharp, G.; Mount, G.

2017-12-01

Acid mine drainage pollutes over 3000 miles of streams and ground water in Pennsylvania alone, and in response many solutions have been developed to counteract the effects of acidic mine drainage. It is estimated by USGS that restoring these watersheds would cost 5 billion-15 billion in total. As economic conditions place limits on expenditures, cost effective means of remediation will be of critical importance. One such method is passive bioremediation, and in the case of metal contamination, self-sustaining oxygenation. Our location of interest is the Tanoma Acid Mine Drainage engineered wetland near Tanoma, Pennsylvania. It is estimated that up to 5,000 gallons per minute is currently being discharged into the site. While most local remediation sites are acidic (pH <4), the Tanoma wetland allows for the study of bioremediation in more neutral pH setting (pH of 5.5-7.5). In this study, we look to further understand biologic, chemical, and hydrologic controls that contribute to the efficiency of the wetland. Our research will focus on the spatial and temporal distribution of biomass through the wetland system as well as changes in water and soil chemistry. Local biofilm (Leptothrix discophora ) are an important part of the remediation process, using iron from the water as an energy source. The bacteria reduce the iron content of the water, precipitating it onto the pond bed as Terraced Iron Formations (TIF). Terraces iron formations (TIF's) are correlated with localized biofilm-archaea densities where archaea thrive in iron rich sediments. By determining bacteria densities in the wetland through gram stain analysis, we can further understand their role in terraced iron formation creation, find localized TIF's that occur, and correlate methane production due to archaea in that location. Mapping TIF locations and identifying bacteria densities will help determine the bioremediation effects on the overall efficiency of iron reduction throughout the Tanoma AMD passive remediation system.

Campaigning for bioremediation. [Pencillium citrinum, Acremonium falciforme, Alternaria alternata, Ulocladium tuberculatum, Fusarium sp

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

Frankenberger, W.T. Jr.; Karlson, U.

Coaxing indigenous soil microorganisms to munch on toxics may prove the only permanent, cost-effective, and safe technique for cleanup of noxious pollutants like selenium, a widespread environmental contaminant in the western United States. The process from innovation in the laboratory to application in the field has taken more than bioremediation know-how. Media exposure and political and bureaucratic support have been necessary partners with sound science to bring Se cleanup technology as far along as it is today. Before describing their patented Se bioremediation process and chronicling the events that led to environmental cleanup in California, the authors give some backgroundmore » about Se, its geochemistry, and its biochemical and environmental behavior. The bioremediation process optimizes field conditions that allow soil fungi to methylate toxic Se compound to dimethylselenide, a non-toxic gas.« less

Key Factors Controlling the Applicability and Efficiency of Bioremediation of Chlorinated Ethenes In Situ

NASA Astrophysics Data System (ADS)

Zhang, M.; Yoshikawa, M.; Takeuchi, M.; Komai, T.

2012-12-01

Bioremediation has been considered as one of environmentally friendly and cost effective approaches for cleaning up the sites polluted by organic contaminants, such as chlorinated ethenes. Although bioremediation, in its widest sense, is not new, and many researches have been performed on bioremediation of different kinds of pollutants, an effective design and implication of in situ bioremediation still remains a challenging problem because of the complexity. Many factors may affect the applicability and efficiency of bioremediation of chlorinated ethenes in situ, which include the type and concentration of contaminants, biological, geological and hydro-geological conditions of the site, physical and chemical characteristics of groundwater and soils to be treated, as well as the constraints in engineering. In this presentation, an overview together with a detailed discussion on each factor will be provided. The influences of individual factors are discussed using the data obtained or cited from different sites and experiments, and thus under different environmental conditions. The results of this study illustrated that 1) the establishment of microbial consortium is of crucial importance for a complete degradation of chlorinated ethenes, 2) in situ control of favorable conditions for increasing microbial activities for bio-degradation through a designed pathway is the key to success, 3) the focus of a successful remediation system is to design an effective delivery process that is capable of producing adequate amendment mixing of contaminant-degrading bacteria, appropriate concentrations of electron acceptors, electron donors, and microbial nutrients in the subsurface treatment area.

Spatial investigation of some uranium minerals using nuclear microprobe

NASA Astrophysics Data System (ADS)

Valter, Anton A.; Knight, Kim B.; Eremenko, Gelij K.; Magilin, Dmitry V.; Ponomarov, Artem A.; Pisansky, Anatoly I.; Romanenko, Alexander V.; Ponomarev, Alexander G.

2018-01-01

In this work, several individual grains of uranium minerals—uraninite with high content of Ca, Ca-rich boltwoodite, growths of uranophane with β-uranophane, and weeksite—from different uranium deposits were studied by a scanning nuclear microprobe. Particle-induced X-ray emission technique provided by the microprobe (µ-PIXE) was carried out to obtain a concentration and 2D distribution of elements in these minerals. In addition, energy dispersive X-ray spectrometry (SEM-EDS) provided by a scanning electron microscope was used. The types of minerals were determined by X-ray diffraction methods. Results of this study improved the understanding of trace elemental composition of the uranium minerals depending on their origin. Obtained signatures could be linked then to the sample provenance. Such data are important for nuclear forensics to identify the ore types and even specific ore bodies, when only small samples may be available for analysis. In this study, the µ-PIXE technique was used for obtaining the 2D distribution of trace elements that are not commonly measured by SEM-EDS at the relevant concentrations. The detected levels and precisions of elements determination by µ-PIXE were also defined. Using µ-PIXE, several micro mineral inclusions such as phosphate with high level of V and Si were identified. The age of the uranium minerals was estimated due to a significant content of radiogenic Pb that provides an additional parameter for determination of the main attributive characteristics of the minerals. This work also showed that due to its high elemental sensitivity the nuclear microprobe can be a new analytical tool for creating a nuclear forensic database from the known uranium deposits and a subsequent analysis of the intercepted illicit materials.

Spatial investigation of some uranium minerals using nuclear microprobe

NASA Astrophysics Data System (ADS)

Valter, Anton A.; Knight, Kim B.; Eremenko, Gelij K.; Magilin, Dmitry V.; Ponomarov, Artem A.; Pisansky, Anatoly I.; Romanenko, Alexander V.; Ponomarev, Alexander G.

2018-06-01

In this work, several individual grains of uranium minerals—uraninite with high content of Ca, Ca-rich boltwoodite, growths of uranophane with β-uranophane, and weeksite—from different uranium deposits were studied by a scanning nuclear microprobe. Particle-induced X-ray emission technique provided by the microprobe (µ-PIXE) was carried out to obtain a concentration and 2D distribution of elements in these minerals. In addition, energy dispersive X-ray spectrometry (SEM-EDS) provided by a scanning electron microscope was used. The types of minerals were determined by X-ray diffraction methods. Results of this study improved the understanding of trace elemental composition of the uranium minerals depending on their origin. Obtained signatures could be linked then to the sample provenance. Such data are important for nuclear forensics to identify the ore types and even specific ore bodies, when only small samples may be available for analysis. In this study, the µ-PIXE technique was used for obtaining the 2D distribution of trace elements that are not commonly measured by SEM-EDS at the relevant concentrations. The detected levels and precisions of elements determination by µ-PIXE were also defined. Using µ-PIXE, several micro mineral inclusions such as phosphate with high level of V and Si were identified. The age of the uranium minerals was estimated due to a significant content of radiogenic Pb that provides an additional parameter for determination of the main attributive characteristics of the minerals. This work also showed that due to its high elemental sensitivity the nuclear microprobe can be a new analytical tool for creating a nuclear forensic database from the known uranium deposits and a subsequent analysis of the intercepted illicit materials.

Noninvasive Reactor Imaging Using Cosmic-Ray Muons

NASA Astrophysics Data System (ADS)

Miyadera, H.; Fujita, K.; Karino, Y.; Kume, N.; Nakayama, K.; Sano, Y.; Sugita, T.; Yoshioka, K.; Morris, C. L.; Bacon, J. D.; Borozdin, K. N.; Perry, J. O.; Mizokami, S.; Otsuka, Y.; Yamada, D.

2015-10-01

Cosmic-ray-muon imaging is proposed to assess the damages to the Fukushima Daiichi reactors. Simulation studies showed capability of muon imaging to reveal the core conditions.The muon-imaging technique was demonstrated at Toshiba Nuclear Critical Assembly, where the uranium-dioxide fuel assembly was imaged with 3-cm spatial resolution after 1 month of measurement.

Field Implementation Plan for the In-Situ Bioremediation Treatability Study at the Technical Area-V Groundwater Area of Concern

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

Li, Jun

This Field Implementation Plan (FIP) was prepared by Sandia National Laboratories, New Mexico (SNL/NM) and provides instruction on conducting a series of in-situ bioremediation (ISB) tests as described in the Revised Treatability Study Work Plan for In-Situ Bioremediation at the Technical Area-V Groundwater Area of Concern, referred to as the Revised Work Plan in this FIP. The Treatability Study is designed to gravity inject an electron-donor substrate and bioaugmentation bacteria into groundwater via three injection wells to perform bioremediation of the constituents of concern (COCs), nitrate and trichloroethene (TCE), in the regions with the highest concentrations at the Technical Area-Vmore » Groundwater (TAVG) Area of Concern (AOC). The Treatability Study will evaluate the effectiveness of bioremediation solution delivery and COC treatment over time. This FIP is designed for SNL/NM work planning and management. It is not intended to be submitted for regulator’s approval. The technical details presented in this FIP are subject to change based on field conditions, availability of equipment and materials, feasibility, and inputs from Sandia personnel and Aboveground Injection System contractor.« less

In situ bioremediation in Europe

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

Porta, A.; Young, J.K.; Molton, P.M.

1993-06-01

Site remediation activity in Europe is increasing, even if not at the forced pace of the US. Although there is a better understanding of the benefits of bioremediation than of other approaches, especially about in situ bioremediation of contaminated soils, relatively few projects have been carried out full-scale in Europe or in the US. Some engineering companies and large industrial companies in Europe are investigating bioremediation and biotreatment technologies, in some cases to solve their internal waste problems. Technologies related to the application of microorganisms to the soil, release of nutrients into the soil, and enhancement of microbial decontamination aremore » being tested through various additives such as surfactants, ion exchange resins, limestone, or dolomite. New equipment has been developed for crushing and mixing or injecting and sparging the microorganisms, as have new reactor technologies (e.g., rotating aerator reactors, biometal sludge reactors, and special mobile containers for simultaneous storage, transportation, and biodegradation of contaminated soil). Some work has also been done with immobilized enzymes to support and restore enzymatic activities related to partial or total xenobiotic decontamination. Finally, some major programs funded by public and private institutions confirm that increasing numbers of firms have a working interest in bioremediation.« less

Application of gamma ray spectrometric measurements and VLF-EM data for tracing vein type uranium mineralization

NASA Astrophysics Data System (ADS)

Gaafar, Ibrahim

2015-12-01

This study is an attempt to use the gamma ray spectrometric measurements and VLF-EM data to identify the subsurface structure and map uranium mineralization along El Sela shear zone, South Eastern Desert of Egypt. Many injections more or less mineralized with uranium and associated with alteration processes were recorded in El Sela shear zone. As results from previous works, the emplacement of these injections is structurally controlled and well defined by large shear zones striking in an ENE-WSW direction and crosscut by NW-SE to NNW-SSE fault sets. VLF method has been applied to map the structure and the presence of radioactive minerals that have been delineated by the detection of high uranium mineralization. The electromagnetic survey was carried out to detect the presence of shallow and deep conductive zones that cross the granites along ENE-WSW fracturing directions and to map its spatial distribution. The survey comprised seventy N-S spectrometry and VLF-EM profiles with 20 m separation. The resulted data were displayed as composite maps for K, eU and eTh as well as VLF-Fraser map. Twelve profiles with 100 m separation were selected for detailed description. The VLF-EM data were interpreted qualitatively as well as quantitatively using the Fraser and the Karous-Hjelt filters. Fraser filtered data and relative current density pseudo-sections indicate the presence of shallow and deep conductive zones that cross the granites along ENE-WSW shearing directions. High uranium concentrations found just above the higher apparent current-density zones that coincide with El-Sela shear zone indicate a positive relation between conductivity and uranium minerals occurrence. This enables to infer that the anomalies detected by VLF-EM data are due to the highly conductive shear zone enriched with uranium mineralization extending for more than 80 m.

BIOREMEDIATION OF HAZARDOUS WASTES

EPA Science Inventory

In 1987, the U.S. Environmental Protection Agency's (EPA) Office of Research and Development (ORD) initiated the Biosystems Technology Development Program to anticipate and address research needs in managing our nation's hazardous waste. The Agency believes that bioremediation of...

ORD RESEARCH PRIORITIES IN BIOREMEDIATION

EPA Science Inventory

ORD is conducting research on bioremediation impacting Superfund sites, RCRA facilities, underground storage tanks and oil spills. Work supporting Superfund is focused on understanding monitored natural recovery in sediments for contaminants including PCBs and PAHs. Under RCRA,...

Applied remediation of petroleum hydrocarbons 3(6)

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

Hinchee, R.E.; Kittel, J.A.; Reisinger, H.J.

1995-12-31

This volume provides sound scientific and engineering approaches. Sections of this volume cover bioremediation markets, general technology overviews, and selected case studies of crude oil spills in marine environments, heavy-metal co-contamination, steam injection, nitrate-based bioremediation, land farming, nutrient addition, confined aquifers, anaerobic biodegradation, free-product recovery technologies, bioremediation in low permeability soils and rock, biopile treatment, field-scale studies, oily waste organics as soil amendments, BTEX degradation in a biofilter, surfactant-aided recovery, mass transport in BTEX removal, electron acceptor selection and delivery strategies, and electrokinetic moisture and nutrient control in unsaturated soils.

Review of heavy metal bio-remediation in contaminated freeway facilitated by adsorption

NASA Astrophysics Data System (ADS)

Zheng, Chaocheng

2017-08-01

Toxicity around biological systems is a significant issue for environmental health in a long term. Recent biotechnological approaches for bio-remediation of heavy metals in freeway frequently include mineralization, bio-adsorption or even remediation. Thus, adequate restoration in freeway requiring cooperation, integration and assimilation of such biotechnological advances along with traditional and ethical wisdom to unravel the mystery of nature in the emerging field of bio-remediation was reviewed with highlights to better understand problems associated with toxicity of heavy metals and eco-friendly technologies.

An application of adaption-innovation theory to bioremediation

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

Guerin, L.J.; Guerin, T.F.

1995-12-31

This paper provides a discussion of the potential application of the Kirton Adaption-Innovation Inventory (KAI) for assessing the adaptive-innovative cognitive style of individuals and organizations within the bioremediation industry. Human-resource and line managers, or other individuals responsible for staff evaluation, selection, and project planning, should consider using the KAI to assist them in selecting individuals for specific roles requiring either an innovative or adaptive style. The KAI, a measure for assessing adaption-innovation at the individual employee level, is introduced and its potential value in the bioremediation industry is discussed.

Impact of quaternary climate on seepage at Yucca Mountain, Nevada

USGS Publications Warehouse

Whelan, J.F.; Paces, J.B.; Neymark, L.A.; Schmitt, A.K.; Grove, M.

2006-01-01

Uranium-series ages, oxygen-isotopic compositions, and uranium contents were determined in outer growth layers of opal and calcitefrom 0.5- to 3-centimeter-thick mineral coatings hosted by lithophysal cavities in the unsaturated zone at Yucca Mountain, Nevada, the proposed site of a permanent repository for high-level radioactive waste. Micrometer-scale growth layering in the minerals was imaged using a cathodoluminescence detector on a scanning electron microscope. Determinations of the chemistry, ages, and delta oxygen-18 (??18O) values of the growth layers were conducted by electron microprobe analysis and secondary ion mass spectrometry techniques at spatial resolutions of 2 to about 20 micrometers (??m) and 25 to 40 ??m, respectively. Growth rates for the last 300 thousand years (k.y.) calculated from about 300 new high-resolution uranium-series ages range from approximately 0.5 to 1.5 ??m/k.y. for 1- to 3-centimeter-thick coatings, whereas coatings less than about 1-centimeter-thick have growth rates less than 0.5 ??m/k.y. At the depth of the proposed repository, correlations of uranium concentration and ??18O values with regional climate records indicate that unsaturated zone percolation and seepage water chemistries have responded to changes in climate during the last several hundred thousand years.

Newly recognized hosts for uranium in the Hanford Site vadose zone

USGS Publications Warehouse

Stubbs, J.E.; Veblen, L.A.; Elbert, D.C.; Zachara, J.M.; Davis, J.A.; Veblen, D.R.

2009-01-01

Uranium contaminated sediments from the U.S. Department of Energy's Hanford Site have been investigated using electron microscopy. Six classes of solid hosts for uranium were identified. Preliminary sediment characterization was carried out using optical petrography, and electron microprobe analysis (EMPA) was used to locate materials that host uranium. All of the hosts are fine-grained and intergrown with other materials at spatial scales smaller than the analytical volume of the electron microprobe. A focused ion beam (FIB) was used to prepare electron-transparent specimens of each host for the transmission electron microscope (TEM). The hosts were identified as: (1) metatorbernite [Cu(UO2)2(PO4)2??8H2O]; (2) coatings on sediment clasts comprised mainly of phyllosilicates; (3) an amorphous zirconium (oxyhydr)oxide found in clast coatings; (4) amorphous and poorly crystalline materials that line voids within basalt lithic fragments; (5) amorphous palagonite surrounding fragments of basaltic glass; and (6) Fe- and Mn-oxides. These findings demonstrate the effectiveness of combining EMPA, FIB, and TEM to identify solid-phase contaminant hosts. Furthermore, they highlight the complexity of U geochemistry in the Hanford vadose zone, and illustrate the importance of microscopic transport in controlling the fate of contaminant metals in the environment. ?? 2008 Elsevier Ltd.

Estimation of in-situ bioremediation system cost using a hybrid Extreme Learning Machine (ELM)-particle swarm optimization approach

NASA Astrophysics Data System (ADS)

Yadav, Basant; Ch, Sudheer; Mathur, Shashi; Adamowski, Jan

2016-12-01

In-situ bioremediation is the most common groundwater remediation procedure used for treating organically contaminated sites. A simulation-optimization approach, which incorporates a simulation model for groundwaterflow and transport processes within an optimization program, could help engineers in designing a remediation system that best satisfies management objectives as well as regulatory constraints. In-situ bioremediation is a highly complex, non-linear process and the modelling of such a complex system requires significant computational exertion. Soft computing techniques have a flexible mathematical structure which can generalize complex nonlinear processes. In in-situ bioremediation management, a physically-based model is used for the simulation and the simulated data is utilized by the optimization model to optimize the remediation cost. The recalling of simulator to satisfy the constraints is an extremely tedious and time consuming process and thus there is need for a simulator which can reduce the computational burden. This study presents a simulation-optimization approach to achieve an accurate and cost effective in-situ bioremediation system design for groundwater contaminated with BTEX (Benzene, Toluene, Ethylbenzene, and Xylenes) compounds. In this study, the Extreme Learning Machine (ELM) is used as a proxy simulator to replace BIOPLUME III for the simulation. The selection of ELM is done by a comparative analysis with Artificial Neural Network (ANN) and Support Vector Machine (SVM) as they were successfully used in previous studies of in-situ bioremediation system design. Further, a single-objective optimization problem is solved by a coupled Extreme Learning Machine (ELM)-Particle Swarm Optimization (PSO) technique to achieve the minimum cost for the in-situ bioremediation system design. The results indicate that ELM is a faster and more accurate proxy simulator than ANN and SVM. The total cost obtained by the ELM-PSO approach is held to a minimum while successfully satisfying all the regulatory constraints of the contaminated site.

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

PubMed

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

2005-02-01

Evaluation of contaminated sites is usually performed by chemical analysis of pollutants in soil. This is not enough either to evaluate the environmental risk of contaminated soil nor to evaluate the efficiency of soil cleanup techniques. Information on the bioavailability of complex mixtures of xenobiotics and degradation products cannot be totally provided by chemical analytical data, but results from bioassays can integrate the effects of pollutants in complex mixtures. In the preservation of human health and environment quality, it is important to assess the ecotoxicological effects of contaminated soils to obtain a better evaluation of the healthiness of this system. The monitoring of a diesel-contaminated soil and the evaluation of a bioremediation technique conducted on a microcosm scale were performed by a battery of ecotoxicological tests including phytotoxicity, Daphnia magna, and nematode assays. In this study we biostimulated the native microflora of soil contaminated with diesel by adding nutrients and crop residue (corn straw) as a bulking agent and as a source of microorganisms and nutrients; in addition, moisture was adjusted to enhance diesel removal. The bioremediation process efficiency was evaluated directly by an innovative, simple phytotoxicity test system and the diesel extracts by Daphnia magna and nematode assays. Contaminated soil samples were revealed to have toxic effects on seed germination, seedling growth, and Daphnia survival. After biostimulation, the diesel concentration was reduced by 50.6%, and the soil samples showed a significant reduction in phytotoxicity (9%-15%) and Daphnia assays (3-fold), confirming the effectiveness of the bioremediation process. Results from our microcosm study suggest that in addition to the evaluation of the bioremediation processes efficiency, toxicity testing is different with organisms representative of diverse phylogenic levels. The integration of analytical, toxicological and bioremediation data is necessary to properly assess the ecological risk of bioremediation processes. (c) 2005 Wiley Periodicals, Inc.

SITE TECHNOLOGY CAPSULE: GRACE DEARBORN INC.'S DARAMEND BIOREMEDIATION TECHNOLOGY

EPA Science Inventory

Grace Dearborn's DARAMEND Bioremediation Technology was developed to treat soils/sediment contaminated with organic contaminants using solid-phase organic amendments. The amendments increase the soil's ability to supply biologically available water/nutrients to microorganisms and...

Guidelines for the Bioremediation of Marine Shorelines and Freshwater Wetlands

EPA Pesticide Factsheets

For oil spill responders:presents rational approach, evaluates current practices and state-of-the-art research results pertaining to bioremediation of hydrocarbon contamination relative to types and amounts of amendments used, application frequency, extent

DEMONSTRATION BULLETIN: GRACE DEARBORN INC. DARAMEND™ BIOREMEDIATION TECHNOLOGY

EPA Science Inventory

The DARAMEND™ Bioremediation Technology may be applied to the remediation of soils and sediments contaminated by a wide variety of organic contaminants including chlorinated phenols, polynuclear aromatic hydrocarbons (PAHs), and petroleum hydrocarbons. The technology may be ap...

Remediation of petroleum hydrocarbon-contaminated sites by DNA diagnosis-based bioslurping technology.

PubMed

Kim, Seungjin; Krajmalnik-Brown, Rosa; Kim, Jong-Oh; Chung, Jinwook

2014-11-01

The application of effective remediation technologies can benefit from adequate preliminary testing, such as in lab-scale and Pilot-scale systems. Bioremediation technologies have demonstrated tremendous potential with regards to cost, but they cannot be used for all contaminated sites due to limitations in biological activity. The purpose of this study was to develop a DNA diagnostic method that reduces the time to select contaminated sites that are good candidates for bioremediation. We applied an oligonucleotide microarray method to detect and monitor genes that lead to aliphatic and aromatic degradation. Further, the bioremediation of a contaminated site, selected based on the results of the genetic diagnostic method, was achieved successfully by applying bioslurping in field tests. This gene-based diagnostic technique is a powerful tool to evaluate the potential for bioremediation in petroleum hydrocarbon contaminated soil. Copyright © 2014 Elsevier B.V. All rights reserved.

Monitoring Arthrobacter protophormiae RKJ100 in a 'tag and chase' method during p-nitrophenol bio-remediation in soil microcosms.

PubMed

Pandey, Gunjan; Pandey, Janmejay; Jain, Rakesh K

2006-05-01

Monitoring of micro-organisms released deliberately into the environment is essential to assess their movement during the bio-remediation process. During the last few years, DNA-based genetic methods have emerged as the preferred method for such monitoring; however, their use is restricted in cases where organisms used for bio-remediation are not well characterized or where the public domain databases do not provide sufficient information regarding their sequence. For monitoring of such micro-organisms, alternate approaches have to be undertaken. In this study, we have specifically monitored a p-nitrophenol (PNP)-degrading organism, Arthrobacter protophormiae RKJ100, using molecular methods during PNP degradation in soil microcosm. Cells were tagged with a transposon-based foreign DNA sequence prior to their introduction into PNP-contaminated microcosms. Later, this artificially introduced DNA sequence was PCR-amplified to distinguish the bio-augmented organism from the indigenous microflora during PNP bio-remediation.

An overview of electrokinetic soil flushing and its effect on bioremediation of hydrocarbon contaminated soil.

PubMed

Ramadan, Bimastyaji Surya; Sari, Gina Lova; Rosmalina, Raden Tina; Effendi, Agus Jatnika; Hadrah

2018-07-15

Combination of electrokinetic soil flushing and bioremediation (EKSF-Bio) technology has attracted many researchers attention in the last few decades. Electrokinetic is used to increase biodegradation rate of microorganisms in soil pores. Therefore, it is necessary to use solubilizing agents such as surfactants that can improve biodegradation process. This paper describes the basic understanding and recent development associated with electrokinetic soil flushing, bioremediation, and its combination as innovative hybrid solution for treating hydrocarbon contaminated soil. Surfactant has been widely used in many studies and practical applications in remediation of hydrocarbon contaminant, but specific review about those combination technology cannot be found. Surfactants and other flushing/solubilizing agents have significant effects to increase hydrocarbon remediation efficiency. Thus, this paper is expected to provide clear information about fundamental interaction between electrokinetic, flushing agents and bioremediation, principal factors, and an inspiration for ongoing and future research benefit. Copyright © 2018 Elsevier Ltd. All rights reserved.

Marine Oil-Degrading Microorganisms and Biodegradation Process of Petroleum Hydrocarbon in Marine Environments: A Review.

PubMed

Xue, Jianliang; Yu, Yang; Bai, Yu; Wang, Liping; Wu, Yanan

2015-08-01

Due to the toxicity of petroleum compounds, the increasing accidents of marine oil spills/leakages have had a significant impact on our environment. Recently, different remedial techniques for the treatment of marine petroleum pollution have been proposed, such as bioremediation, controlled burning, skimming, and solidifying. (Hedlund and Staley in Int J Syst Evol Microbiol 51:61-66, 2001). This review introduces an important remedial method for marine oil pollution treatment-bioremediation technique-which is considered as a reliable, efficient, cost-effective, and eco-friendly method. First, the necessity of bioremediation for marine oil pollution was discussed. Second, this paper discussed the species of oil-degrading microorganisms, degradation pathways and mechanisms, the degradation rate and reaction model, and the factors affecting the degradation. Last, several suggestions for the further research in the field of marine oil spill bioremediation were proposed.

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

Deng, Ye; Zhang, Ping; Qin, Yujia

When trying to discern network interactions among different species/populations in microbial communities interests have been evoked in recent years, but little information is available about temporal dynamics of microbial network interactions in response to environmental perturbations. We modified the random matrix theory-based network approach to discern network succession in groundwater microbial communities in response to emulsified vegetable oil (EVO) amendment for uranium bioremediation. Groundwater microbial communities from one control and seven monitor wells were analysed with a functional gene array (GeoChip 3.0), and functional molecular ecological networks (fMENs) at different time points were reconstructed. Our results showed that the networkmore » interactions were dramatically altered by EVO amendment. Dynamic and resilient succession was evident: fairly simple at the initial stage (Day 0), increasingly complex at the middle period (Days 4, 17, 31), most complex at Day 80, and then decreasingly complex at a later stage (140–269 days). Unlike previous studies in other habitats, negative interactions predominated in a time-series fMEN, suggesting strong competition among different microbial species in the groundwater systems after EVO injection. In particular, several keystone sulfate-reducing bacteria showed strong negative interactions with their network neighbours. These results provide mechanistic understanding of the decreased phylogenetic diversity during environmental perturbations.« less

Cadmium biosorption by Streptomyces sp. F4 isolated from former uranium mine.

PubMed

Siñeriz, Manuel Louis; Kothe, Erika; Abate, Carlos Mauricio

2009-09-01

46 actinomycetes were isolated from two polluted sites and one unpolluted site. One strain, F4, was selected through primary qualitative screening assays because of its cadmium resistance, and physiologically and taxonomically characterized. F4 was able to grow at 7.5% NaCl and 100 microg/ml lysozyme and at a pH between 6 and 10. 16S rDNA sequence analysis showed that F4 was closely related to Streptomyces tendae. Growth of Streptomyces sp. F4 on culture medium with 8 mg/l Cd(2+) for 8 days showed 80% inhibition. Maximum specific biosorption was 41.7 mg Cd(2+)/g dry weight after 7 days of growth and highest Cd(2+ )concentration was found in the cell wall (41.2%). The exopolysaccharide layer only contained 7.4%, whereas 39.4% of Cd(2+) was found in the cytosolic fraction. Twelve % was found in the ribosomes and membrane fraction. This was verified with TEM, showing Streptomyces sp. F4 cytoplasm with dark granulate appearance. This study could present the potential capacity of Streptomyces sp. F4 for Cd(2+) bioremediation. Copyright 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Field evaluations of marine oil spill bioremediation.

PubMed Central

Swannell, R P; Lee, K; McDonagh, M

1996-01-01

Bioremediation is defined as the act of adding or improving the availability of materials (e.g., nutrients, microorganisms, or oxygen) to contaminated environments to cause an acceleration of natural biodegradative processes. The results of field experiments and trials following actual spill incidents have been reviewed to evaluate the feasibility of this approach as a treatment for oil contamination in the marine environment. The ubiquity of oil-degrading microorganisms in the marine environment is well established, and research has demonstrated the capability of the indigenous microflora to degrade many components of petroleum shortly after exposure. Studies have identified numerous factors which affect the natural biodegradation rates of oil, such as the origin and concentration of oil, the availability of oil-degrading microorganisms, nutrient concentrations, oxygen levels, climatic conditions, and sediment characteristics. Bioremediation strategies based on the application of fertilizers have been shown to stimulate the biodegradation rates of oil in aerobic intertidal sediments such as sand and cobble. The ratio of oil loading to nitrogen concentration within the interstitial water has been identified to be the principal controlling factor influencing the success of this bioremediation strategy. However, the need for the seeding of natural environments with hydrocarbon-degrading bacteria has not been clearly demonstrated under natural environmental conditions. It is suggested that bioremediation should now take its place among the many techniques available for the treatment of oil spills, although there is still a clear need to set operational limits for its use. On the basis of the available evidence, we have proposed preliminary operational guidelines for bioremediation on shoreline environments. PMID:8801437

Biosensing and bioremediation of Cr(VI) by cell free extract of Enterobacter aerogenes T2.

PubMed

Panda, Jigisha; Sarkar, Priyabrata

2014-01-01

Hexavalent chromium or Cr(VI) enters the environment through several anthropogenic activities and it is highly toxic and carcinogenic. Hence it is required to be detected and remediated from the environment. In this study, low-cost and environment-friendly methods of biosensing and bioremediation of Cr(VI) have been proposed. Crude cell free extract (CFE) of previously isolated Enterobacter aerogenes T2 (GU265554; NII 1111) was prepared and exploited to develop a stable biosensor for direct estimation of Cr(VI) in waste water, by using three electrodes via cyclic voltammetry. For bioremediation studies, a homogeneous solution of commercially available sodium alginate and CFE was added dropwise in a continuously stirred calcium chloride solution. Biologically modified calcium alginate beads were produced and these were further utilized for bioremediation studies. The proposed sensor showed linear response in the range of 10-40 μg L(-1) Cr(VI) and the limit of detection was found to be 6.6 μg L(-1) Cr(VI). No interference was observed in presence of metal ions, e.g., lead, cadmium, arsenic, tin etc., except for insignificant interference with molybdenum and manganese. In bioremediation studies, modified calcium alginate beads showed encouraging removal rate 900 mg Cr(VI)/m(3) water per day with a removal efficiency of 90%, much above than reported in literature. The proposed sensing system could be a viable alternative to costly measurement procedures. Calcium alginate beads, modified with CFE of E. aerogenes, could be used in bioremediation of Cr(VI) since it could work in real conditions with extraordinarily high capacity.

Impact of chemical oxidation on indigenous bacteria and mobilization of nutrients and subsequent bioremediation of crude oil-contaminated soil.

PubMed

Xu, Jinlan; Deng, Xin; Cui, Yiwei; Kong, Fanxing

2016-12-15

Fenton pre-oxidation provides nutrients to promote bioremediation. However, the effects of the indigenous bacteria that remain following Fenton oxidation on nutrient mobilization and subsequent bioremediation remain unclear. Experiments were performed with inoculation with native bacteria and foreign bacteria or without inoculation after four regimens of stepwise pre-oxidations. The effects of the indigenous bacteria remaining after stepwise oxidation on nutrient mobilization and subsequent bioremediation over 80 days were investigated. After stepwise Fenton pre-oxidation at a low H 2 O 2 concentration (225×4), the remaining indigenous bacterial populations reached their peak (4.8±0.17×10 6 CFU/g), the nutrients were mobilized rapidly, and the subsequent bioremediation of crude oil was improved (biodegradation efficiency of 35%). However, after stepwise Fenton pre-oxidation at a high H 2 O 2 concentration (450×4), only 3.6±0.16×10 3 CFU/g of indigenous bacteria remained, and the indigenous bacteria that degrade C 15 -C 30 alkanes were inhibited. The nutrient mobilization was then highly limited, and only 19% of total petroleum hydrocarbon was degraded. Furthermore, the recovery period after the low H 2 O 2 concentration stepwise Fenton pre-oxidation (225×4) was less than 20 days, which was 20-30 days shorter than with the other pre-oxidation treatments. Therefore, stepwise Fenton pre-oxidation at a low H 2 O 2 concentration protects indigenous bacterial populations and improves the nutrient mobilization and subsequent bioremediation. Copyright © 2016 Elsevier B.V. All rights reserved.

pH and Organic Carbon Dose Rates Control Microbially Driven Bioremediation Efficacy in Alkaline Bauxite Residue.

PubMed

Santini, Talitha C; Malcolm, Laura I; Tyson, Gene W; Warren, Lesley A

2016-10-18

Bioremediation of alkaline tailings, based on fermentative microbial metabolisms, is a novel strategy for achieving rapid pH neutralization and thus improving environmental outcomes associated with mining and refining activities. Laboratory-scale bioreactors containing bauxite residue (an alkaline, saline tailings material generated as a byproduct of alumina refining), to which a diverse microbial inoculum was added, were used in this study to identify key factors (pH, salinity, organic carbon supply) controlling the rates and extent of microbially driven pH neutralization (bioremediation) in alkaline tailings. Initial tailings pH and organic carbon dose rates both significantly affected bioremediation extent and efficiency with lower minimum pHs and higher extents of pH neutralization occurring under low initial pH or high organic carbon conditions. Rates of pH neutralization (up to 0.13 mM H + produced per day with pH decreasing from 9.5 to ≤6.5 in three days) were significantly higher in low initial pH treatments. Representatives of the Bacillaceae and Enterobacteriaceae, which contain many known facultative anaerobes and fermenters, were identified as key contributors to 2,3-butanediol and/or mixed acid fermentation as the major mechanism(s) of pH neutralization. Initial pH and salinity significantly influenced microbial community successional trajectories, and microbial community structure was significantly related to markers of fermentation activity. This study provides the first experimental demonstration of bioremediation in bauxite residue, identifying pH and organic carbon dose rates as key controls on bioremediation efficacy, and will enable future development of bioreactor technologies at full field scale.

ELECTROKINETICS, INC. INSITU BIO REMEDIATION BY ELECTROKINETIC INJECTION EMERGING TECHNOLOGY SUMMARY

EPA Science Inventory

Electrokinetics, Inc. through a cooperative agreement with USEPA's NRMRL conducted a laboratory evaluation of electrokinetic transport as a means to enhance in-situ bioremediation of trichloroethene (TCE). Four critical aspects of enhancing bioremediation by electrokinetic inject...

ANAEROBIC BIOREMEDIATION OF CHLORINATED ETHENES

EPA Science Inventory

The failure of what have been termed convential methods to reclaim contaminated environmental media has over the years lead to the interest and development of alternative technologies. One of these technologies is bioremediation, or the utilization of microbial agents to reduce ...

BIOREMEDIATION

EPA Science Inventory

Bioremediation is a method for using the activities of microorganisms and-or plants to transform organic or inorganic compounds that may be harmful to humans, animals, plants or the environment to compounds that are less harmful. In many instances the toxic compounds may be compl...

BIOREMEDIATION AT WOOD-PRESERVING SITES

EPA Science Inventory

The removal of organic compounds from ground water during bioremediation at wood-preserving sites is a function of the stoichiometric demand for electron acceptors (oxygen, nitrate, and sulfate) to metabolize the organic contaminants and the supply of the electron acceptors in th...

PROTOCOL FOR LABORATORY TESTING OF CRUDE-OIL BIOREMEDIATION PRODUCTS IN FRESHWATER CONDITIONS

EPA Science Inventory

In 1993, the Environmental Protection Agency, National Risk Management Research Laboratory (EPA, NRMRL), with the National Environmental Technology Application Center (NETAC), developed a protocol for evaluation of bioremediation products in marine environments. The marine proto...

Multi-Objective Optimization of an In situ Bioremediation Technology to Treat Perchlorate-Contaminated Groundwater

EPA Science Inventory

The presentation shows how a multi-objective optimization method is integrated into a transport simulator (MT3D) for estimating parameters and cost of in-situ bioremediation technology to treat perchlorate-contaminated groundwater.

Bioaccessible Porosity in Soil Aggregates and Implications for Biodegradation of High Molecular Weight Petroleum Compounds.

PubMed

Akbari, Ali; Ghoshal, Subhasis

2015-12-15

We evaluated the role of soil aggregate pore size on biodegradation of essentially insoluble petroleum hydrocarbons that are biodegraded primarily at the oil-water interface. The size and spatial distribution of pores in aggregates sampled from biodegradation experiments of a clayey, aggregated, hydrocarbon-contaminated soil with relatively high bioremediation end point were characterized by image analyses of X-ray micro-CT scans and N2 adsorption. To determine the bioaccessible pore sizes, we performed separate experiments to assess the ability of hydrocarbon degrading bacteria isolated from the soil to pass through membranes with specific sized pores and to access hexadecane (model insoluble hydrocarbon). Hexadecane biodegradation occurred only when pores were 5 μm or larger, and did not occur when pores were 3 μm and smaller. In clayey aggregates, ∼ 25% of the aggregate volume was attributed to pores larger than 4 μm, which was comparable to that in aggregates from a sandy, hydrocarbon-contaminated soil (~23%) scanned for comparison. The ratio of volumes of inaccessible pores (<4 μm) to bioaccessible pores (>4 μm) in the clayey aggregates was 0.32, whereas in the sandy aggregates it was approximately 10 times lower. The role of soil microstructure on attainable bioremediation end points could be qualitatively assessed in various soils by the aggregate characterization approach outlined herein.

GROUND WATER REMEDIATION RESEARCH: ENHANCED BIOREMEDIATION AND MONITORED NATURAL ATTENUATION

EPA Science Inventory

An overview of ground water remediation research conducted at the Subsurface Protection and Remediation Division is provided. The focus of the overview is on Enhanced Bioremediation and Monitored Natural Attenuation research for the remediation of organic and inorganic contamina...

Framing bioremediation decision making as negotiation: Rationale & guidelineFraming bioremediation decision making as negotiation: Rationale & guidelines

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

Bjornstad, David J.; Wolfe, Amy K.

Framing remediation decision making as negotiation: (1) social choice, not technology choice; (2) prompts decision makers to identify interested and affected parties, anticipate objections, effectively address and ameliorate objections, and avoid unacceptable decisions.

SITE TECHNOLOGY CAPSULE: J.R. SIMPLOT EX-SITU BIOREMEDIATION TECHNOLOGY: DINOSEB

EPA Science Inventory

The J.R. Simplot Ex-Situ Bioremediation Technology is designed to anaerobically degrade nitroaromatic and energetic compounds in soils and liquids without forming identifiable toxic intermediate compounds produced by other biotreatment methods. This technology was evaluated un...

Augmented In Situ Subsurface Bioremediation Process™BIO-REM, Inc. - Demonstration Bulletin

EPA Science Inventory

The Augmented In Situ Subsurface Bioremediation Process™ developed by BIO-REM, Inc., uses microaerophilic bacteria and micronutrients (H-10) and surface tension depressants/penetrants for the treatment of hydrocarbon contaminated soils and groundwater. The bacteria utilize hydroc...

BIOREMEDIATION IN THE FIELD SEARCH SYSTEM (BFSS) - USER DOCUMENTATION

EPA Science Inventory

The Bioremediation Field Initiative is a cooperative effort of the U.S. EPA's Office of Research and Development (ORD), Office of Solid Waste and Emergency Response (OSWER), and regional offices, and other federal agencies, state agencies, industry, and universities to ...

[Ecological characteristics of phytoplankton in Suining tributary under bio-remediation].

PubMed

Liu, Dongyan; Zhao, Jianfu; Zhang, Yalei; Ma, Limin

2005-04-01

Based on the analyses of phytoplankton community in the treated and untreated reaches of Suining tributary of Suzhou River, this paper studied the effects of bio-remediation on phytoplankton. As the result of the remediation, the density and Chl-a content of phytoplankton in treated reach were greatly declined, while the species number and Shannon-Wiener diversity index ascended obviously. The percentage of Chlorophyta and Baeillariophyta ascended, and some species indicating medium-and oligo-pollution were found. All of these illustrated that bio-remediation engineering might significantly benefit to the improvement of phytoplankton community structure and water quality.

Genetic analysis of stress responses in soil bacteria for enhanced bioremediation of mixed contaminants. 1997 annual progress report

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

Wong, K.K.

'To provide increased knowledge of stress responses of indigenous microbes at contaminated sites as well as using microbes as molecular probes for monitoring the performance and effectiveness of bioremediation, the authors propose to identify the stress-inducible genes and promoters from two soil bacteria, Deinococcus radiodurans and Sphingomonas F199. These organisms represent two phylogenetically distinct groups of soil bacteria, each of which has specific features of interest for bioremediation. D. radiodurans exhibits high resistance to external stress; F199 is a deep subsurface (Savannah River Site) organism with unique degradative capabilities. Research Statement To realize the full potential of bioremediation, an understandingmore » of microbial community and individual bacterial responses to the stresses encountered at contaminated sites is needed. Knowledge about genetic responses of soil and subsurface bacteria to environmental stresses, which include low nutrients, low oxygen, and mixed pollutants, will allow extrapolation of basic principles to field applications either using indigenous bacteria or genetically engineered microorganisms. Defining bacterial responses to those stresses presents an opportunity for improving bioremediation strategies, and should contribute to environmental management and restoration actions that would reduce the cost and time required to achieve DOE''s cleanup goals.'« less

Evaluating the Effects of Bioremediation on Genotoxicity of Polycyclic Aromatic Hydrocarbon-Contaminated Soil Using Genetically Engineered, Higher Eukaryotic Cell Lines

PubMed Central

Hu, Jing; Nakamura, Jun; Richardson, Stephen D.; Aitken, Michael D.

2012-01-01

Bioremediation is one of the commonly applied remediation strategies at sites contaminated with polycyclic aromatic hydrocarbons (PAHs). However, remediation goals are typically based on removal of the target contaminants rather than on broader measures related to health risks. We investigated changes in the toxicity and genotoxicity of PAH-contaminated soil from a former manufactured-gas plant site before and after two simulated bioremediation processes: a sequencing batch bioreactor system and a continuous-flow column system. Toxicity and genotoxicity of the residues from solvent extracts of the soil were determined by the chicken DT40 B-lymphocyte isogenic cell line and its DNA-repair-deficient mutants. Although both bioremediation processes significantly removed PAHs from the contaminated soil (bioreactor 69% removal; column 84% removal), bioreactor treatment resulted in an increase in toxicity and genotoxicity over the course of a treatment cycle, whereas long-term column treatment resulted in a decrease in toxicity and genotoxicity. However, when screening with a battery of DT40 mutants for genotoxicity profiling, we found that column treatment induced DNA damage types that were not observed in untreated soil. Toxicity and genotoxicity bioassays can supplement chemical analysis-based risk assessment for contaminated soil when evaluating the efficacy of bioremediation. PMID:22443351

Profiling bacterial communities associated with sediment-based aquaculture bioremediation systems under contrasting redox regimes

NASA Astrophysics Data System (ADS)

Robinson, Georgina; Caldwell, Gary S.; Wade, Matthew J.; Free, Andrew; Jones, Clifford L. W.; Stead, Selina M.

2016-12-01

Deposit-feeding invertebrates are proposed bioremediators in microbial-driven sediment-based aquaculture effluent treatment systems. We elucidate the role of the sediment reduction-oxidation (redox) regime in structuring benthic bacterial communities, having direct implications for bioremediation potential and deposit-feeder nutrition. The sea cucumber Holothuria scabra was cultured on sediments under contrasting redox regimes; fully oxygenated (oxic) and redox stratified (oxic-anoxic). Taxonomically, metabolically and functionally distinct bacterial communities developed between the redox treatments with the oxic treatment supporting the greater diversity; redox regime and dissolved oxygen levels were the main environmental drivers. Oxic sediments were colonised by nitrifying bacteria with the potential to remediate nitrogenous wastes. Percolation of oxygenated water prevented the proliferation of anaerobic sulphate-reducing bacteria, which were prevalent in the oxic-anoxic sediments. At the predictive functional level, bacteria within the oxic treatment were enriched with genes associated with xenobiotics metabolism. Oxic sediments showed the greater bioremediation potential; however, the oxic-anoxic sediments supported a greater sea cucumber biomass. Overall, the results indicate that bacterial communities present in fully oxic sediments may enhance the metabolic capacity and bioremediation potential of deposit-feeder microbial systems. This study highlights the benefits of incorporating deposit-feeding invertebrates into effluent treatment systems, particularly when the sediment is oxygenated.

Comparison of PAH Biodegradation and Desorption Kinetics During Bioremediation of Aged Petroleum Hydrocarbon Contaminated Soils

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

Huesemann, Michael H.; Hausmann, Tom S.; Fortman, Timothy J.

It is commonly assumed that mass-transfer limitations are the cause for slow and incomplete biodegradation of PAHs in aged soils. In order to test this hypothesis, the biodegradation rate and the abiotic release rate were measured and compared for selected PAHs in three different soils. It was found that PAH biodegradation was not mass-transfer limited during slurry bioremediation of an aged loamy soil. By contrast, PAH biodegradation rates were much larger than abiotic release rates in kaolinite clay indicating that sorbed-phase PAHs can apparently be biodegraded directly from mineral surfaces without prior desorption or dissolution into the aqueous phase. Amore » comparison of PAH biodegradation rates and abiotic release rates at termination of the slurry bioremediation treatment revealed that abiotic release rates are much larger than the respective biodegradation rates. In addition, it was found that the number of hydrocarbon degraders decreased by four orders of magnitude during the bioremediation treatment. It can therefore be concluded that the slow and incomplete biodegradation of PAHs is not caused by mass-transfer limitations but rather by microbial factors. Consequently, the residual PAHs that remain after extensive bioremediation treatment are still bioavailable and for that reason could pose a greater risk to environmental receptors than previously thought.« less

Profiling bacterial communities associated with sediment-based aquaculture bioremediation systems under contrasting redox regimes

PubMed Central

Robinson, Georgina; Caldwell, Gary S.; Wade, Matthew J.; Free, Andrew; Jones, Clifford L. W.; Stead, Selina M.

2016-01-01

Deposit-feeding invertebrates are proposed bioremediators in microbial-driven sediment-based aquaculture effluent treatment systems. We elucidate the role of the sediment reduction-oxidation (redox) regime in structuring benthic bacterial communities, having direct implications for bioremediation potential and deposit-feeder nutrition. The sea cucumber Holothuria scabra was cultured on sediments under contrasting redox regimes; fully oxygenated (oxic) and redox stratified (oxic-anoxic). Taxonomically, metabolically and functionally distinct bacterial communities developed between the redox treatments with the oxic treatment supporting the greater diversity; redox regime and dissolved oxygen levels were the main environmental drivers. Oxic sediments were colonised by nitrifying bacteria with the potential to remediate nitrogenous wastes. Percolation of oxygenated water prevented the proliferation of anaerobic sulphate-reducing bacteria, which were prevalent in the oxic-anoxic sediments. At the predictive functional level, bacteria within the oxic treatment were enriched with genes associated with xenobiotics metabolism. Oxic sediments showed the greater bioremediation potential; however, the oxic-anoxic sediments supported a greater sea cucumber biomass. Overall, the results indicate that bacterial communities present in fully oxic sediments may enhance the metabolic capacity and bioremediation potential of deposit-feeder microbial systems. This study highlights the benefits of incorporating deposit-feeding invertebrates into effluent treatment systems, particularly when the sediment is oxygenated. PMID:27941918

Sustainable sources of biomass for bioremediation of heavy metals in waste water derived from coal-fired power generation.

PubMed

Saunders, Richard J; Paul, Nicholas A; Hu, Yi; de Nys, Rocky

2012-01-01

Biosorption of heavy metals using dried algal biomass has been extensively described but rarely implemented. We contend this is because available algal biomass is a valuable product with a ready market. Therefore, we considered an alternative and practical approach to algal bioremediation in which algae were cultured directly in the waste water stream. We cultured three species of algae with and without nutrient addition in water that was contaminated with heavy metals from an Ash Dam associated with coal-fired power generation and tested metal uptake and bioremediation potential. All species achieved high concentrations of heavy metals (to 8% dry mass). Two key elements, V and As, reached concentrations in the biomass of 1543 mg.kg(-1) DW and 137 mg.kg(-1) DW. Growth rates were reduced by more than half in neat Ash Dam water than when nutrients were supplied in excess. Growth rate and bioconcentration were positively correlated for most elements, but some elements (e.g. Cd, Zn) were concentrated more when growth rates were lower, indicating the potential to tailor bioremediation depending on the pollutant. The cosmopolitan nature of the macroalgae studied, and their ability to grow and concentrate a suite of heavy metals from industrial wastes, highlights a clear benefit in the practical application of waste water bioremediation.

Genetic basis and importance of metal resistant genes in bacteria for bioremediation of contaminated environments with toxic metal pollutants.

PubMed

Das, Surajit; Dash, Hirak R; Chakraborty, Jaya

2016-04-01

Metal pollution is one of the most persistent and complex environmental issues, causing threat to the ecosystem and human health. On exposure to several toxic metals such as arsenic, cadmium, chromium, copper, lead, and mercury, several bacteria has evolved with many metal-resistant genes as a means of their adaptation. These genes can be further exploited for bioremediation of the metal-contaminated environments. Many operon-clustered metal-resistant genes such as cadB, chrA, copAB, pbrA, merA, and NiCoT have been reported in bacterial systems for cadmium, chromium, copper, lead, mercury, and nickel resistance and detoxification, respectively. The field of environmental bioremediation has been ameliorated by exploiting diverse bacterial detoxification genes. Genetic engineering integrated with bioremediation assists in manipulation of bacterial genome which can enhance toxic metal detoxification that is not usually performed by normal bacteria. These techniques include genetic engineering with single genes or operons, pathway construction, and alternations of the sequences of existing genes. However, numerous facets of bacterial novel metal-resistant genes are yet to be explored for application in microbial bioremediation practices. This review describes the role of bacteria and their adaptive mechanisms for toxic metal detoxification and restoration of contaminated sites.

The Environmental Issues of DDT Pollution and Bioremediation: a Multidisciplinary Review.

PubMed

Mansouri, Ahlem; Cregut, Mickael; Abbes, Chiraz; Durand, Marie-Jose; Landoulsi, Ahmed; Thouand, Gerald

2017-01-01

DDT (1,1,1-trichloro-2,2-bis(4-chlorophenyl) ethane) is probably the best known and most useful organochlorine insecticide in the world which was used since 1945 for agricultural purposes and also for vector-borne disease control such as malaria since 1955, until its banishment in most countries by the Stockholm convention for ecologic considerations. However, the World Health Organization allowed its reintroduction only for control of vector-borne diseases in some tropical countries in 2006. Due to its physicochemical properties and specially its persistence related with a half-life up to 30 years, DDT linked to several health and social problems which are due to its accumulation in the environment and its biomagnification properties in living organisms. This manuscript compiles a multidisciplinary review to evaluate primarily (i) the worldwide contamination of DDT and (ii) its (eco) toxicological impact onto living organisms. Secondly, several ways for DDT bioremediation from contaminated environment are discussed. For this, reports on DDT biodegradation capabilities by microorganisms and ways to enhance bioremediation strategies to remove DDT are presented. The different existing strategies for DDT bioremediation are evaluated with their efficiencies and limitations to struggle efficiently this contaminant. Finally, rising new approaches and technological bottlenecks to promote DDT bioremediation are discussed.

Assessment of three approaches of bioremediation (Natural Attenuation, Landfarming and Bioagumentation - Assistited Landfarming) for a petroleum hydrocarbons contaminated soil.

PubMed

Guarino, C; Spada, V; Sciarrillo, R

2017-03-01

Contamination with total petroleum hydrocarbons (TPH) subsequent to refining activities, is currently one of the major environmental problems. Among the biological remediation approaches, landfarming and in situ bioremediation strategies are of great interest. Purpose of this study was to verify the feasibility of a remediation process wholly based on biological degradation applied to contaminated soils from a decommissioned refinery. This study evaluated through a pot experiment three bioremediation strategies: a) Natural Attenuation (NA), b) Landfarming (L), c) Bioaugmentation-assisted Landfarming (LB) for the treatment of a contaminated soil with petroleum hydrocarbons (TPHs). After a 90-days trial, Bioagumentation - assistited Landfarming approach produced the best results and the greatest evident effect was shown with the most polluted samples reaching a reduction of about 86% of total petroleum hydrocarbons (TPH), followed by Landfarming (70%), and Natural Attenuation (57%). The results of this study demonstrated that the combined use of bioremediation strategies was the most advantageous option for the treatment of contaminated soil with petroleum hydrocarbons, as compared to natural attenuation, bioaugmentation or landfarming applied alone. Besides, our results indicate that incubation with an autochthonous bacterial consortium may be a promising method for bioremediation of TPH-contaminated soils. Copyright © 2016 Elsevier Ltd. All rights reserved.

ENGINEERING ISSUE: IN SITU BIOREMEDIATION OF CONTAMINATED UNSATURATED SUBSURFACE SOILS

EPA Science Inventory

An emerging technology for the remediation of unsaturated subsurface soils involves the use of microorganisms to degrade contaminants which are present in such soils. Understanding the processes which drive in situ bioremediation, as well as the effectiveness and efficiency of th...

UTILIZATION OF TREATABILITY AND PILOT TESTS TO PREDICT CAH BIOREMEDIATION

EPA Science Inventory

Multiple tools have been suggested to help in the design of enhanced anaerobic bioremediation systems for CAHs:
- Extensive high quality microcosm testing followed by small-scale, thoroughly observed field pilot tests (i.e., RABITT Protocol, Morse 1998)
- More limited ...

Use of Additives in Bioremediation of Contaminated Groundwater and Soil

EPA Science Inventory

This chapter reviews application of additives used in bioremediation of chlorinated solvents and fuels for groundwater and soil remediation. Soluble carbon substrates are applicable to most site conditions except aquifers with very high or very low groundwater flow. Slow-release ...

METRICS OF PERFORMANCE FOR THE SABRE MICROCOSM STUDY (ABSTRACT ONLY)

EPA Science Inventory

The SABRE (Source Area BioREmediation) project will evaluate accelerated anaerobic bioremediation of chlorinated solvents in areas of high concentration, such as DNAPL source areas. In preparation for a field scale pilot test, a laboratory microcosm study was conducted to provide...

ENHANCED BIOREMEDIATION OF SOLVENTS IN A FRACTURED ROCK AQUIFER

EPA Science Inventory

This poster summarizes results of a technology evaluation that was conducted in conjunction with ITT Industries, Earth Tech, Inc., and the US EPA SITE program. The technology evaluated was Enhanced In Situ Bioremediation. The technology was developed at the Department of Ener...

CHARACTERIZING THE MICROBIAL COMMUNITY IN SABRE MICROCOSM STUDIES (ABSTRACT ONLY)

EPA Science Inventory

The SABRE (Source Area BioREmediation) project will evaluate accelerated anaerobic bioremediation of chlorinated solvents in areas of high concentration, such as DNAPL source areas. In preparation for a field scale pilot test, laboratory microcosm and column studies were conducte...

IN-SITU BIOREMEDIATION OF GROUND WATER AND GEOLOGICAL MATERIAL: A REVIEW OF TECHNOLOGIES

EPA Science Inventory

In situ bioremediation of subsurface environments involve the use of microorganisms to convert contaminants to less harmful products and sometimes offers significant potential advantages over other remediation technologies. n order for these biodegradative processes to occur, icr...

ENGINEERING CONCEPTS FOR IN SITU BIOREMEDIATION. (R825689C051)

EPA Science Inventory

Abstract

Most organic materials that contaminate soil and the subsurface environment are readily degraded by natural biological processes. Thus, bioremediation can be thought of as a highly successful purification process. However, some organic molecules are naturally ...

MICROBIAL POPULATION CHANGES DURING BIOREMEDIATION OF AN EXPERIMENTAL OIL SPILL

EPA Science Inventory

Three crude oil bioremediation techniques were applied in a randomized block field experiment simulating a coastal oil-spill. Four treatments (no oil control, oil alone, oil + nutrients, and oil + nutrients + an indigenous inoculum) were applied. In-situ microbial community str...

BIOREMEDIATION OF HAZARDOUS WASTE SITES: PRACTICAL APPROACHES TO IMPLEMENTATION (EPA/625/K-96/001)

EPA Science Inventory

This document contains abstracts and slide hardcopy for the U.S. Environmental Protection Agency's (EPA's) "Seminar Series on Bioremediation of Hazardous Waste Sites: Practical Approaches to Implementation." This technology transfer seminar series, sponsored by EPA's Biosystems ...

Integrated water quality, emergy and economic evaluation of three bioremediation treatment systems for eutrophic water

EPA Science Inventory

This study was targeted at finding one or more environmentally efficient, economically feasible and ecologically sustainable bioremediation treatment modes for eutrophic water. Three biological species, i.e. water spinach (Ipomoea aquatica), loach (Misgurus anguillicaudatus) and ...

BIOREMEDIATION IN THE FIELD - NO. 12, AUGUST 1995

EPA Science Inventory

The Bioremediation Field Initiative is a cooperative effort of the U.S. EPA's Office of Research and Development (ORD), Office of Solid Waste and Emergency Response (OSWER), and regional offices, and other federal agencies, state agencies, industry, and universities to expand the...

Growth and metal bioconcentration by conspecific freshwater macroalgae cultured in industrial waste water.

PubMed

Ellison, Michael B; de Nys, Rocky; Paul, Nicholas A; Roberts, David A

2014-01-01

The bioremediation of industrial waste water by macroalgae is a sustainable and renewable approach to the treatment of waste water produced by multiple industries. However, few studies have tested the bioremediation of complex multi-element waste streams from coal-fired power stations by live algae. This study compares the ability of three species of green freshwater macroalgae from the genus Oedogonium, isolated from different geographic regions, to grow in waste water for the bioremediation of metals. The experiments used Ash Dam water from Tarong power station in Queensland, which is contaminated by multiple metals (Al, Cd, Ni and Zn) and metalloids (As and Se) in excess of Australian water quality guidelines. All species had consistent growth rates in Ash Dam water, despite significant differences in their growth rates in "clean" water. A species isolated from the Ash Dam water itself was not better suited to the bioremediation of that waste water. While there were differences in the temporal pattern of the bioconcentration of metals by the three species, over the course of the experiment, all three species bioconcentrated the same elements preferentially and to a similar extent. All species bioconcentrated metals (Cu, Mn, Ni, Cd and Zn) more rapidly than metalloids (As, Mo and Se). Therefore, bioremediation in situ will be most rapid and complete for metals. Overall, all three species of freshwater macroalgae had the ability to grow in waste water and bioconcentrate elements, with a consistent affinity for the key metals that are regulated by Australian and international water quality guidelines. Together, these characteristics make Oedogonium a clear target for scaled bioremediation programs across a range of geographic regions.

Combination of aquifer thermal energy storage and enhanced bioremediation: Biological and chemical clogging.

PubMed

Ni, Zhuobiao; van Gaans, Pauline; Rijnaarts, Huub; Grotenhuis, Tim

2018-02-01

Interest in the combination concept of aquifer thermal energy storage (ATES) and enhanced bioremediation has recently risen due to the demand for both renewable energy technology and sustainable groundwater management in urban areas. However, the impact of enhanced bioremediation on ATES is not yet clear. Of main concern is the potential for biological clogging which might be enhanced and hamper the proper functioning of ATES. On the other hand, more reduced conditions in the subsurface by enhanced bioremediation might lower the chance of chemical clogging, which is normally caused by Fe(III) precipitate. To investigate the possible effects of enhanced bioremediation on clogging with ATES, we conducted two recirculating column experiments with differing flow rates (10 and 50mL/min), where enhanced biological activity and chemically promoted Fe(III) precipitation were studied by addition of lactate and nitrate respectively. The pressure drop between the influent and effluent side of the column was used as a measure of the (change in) hydraulic conductivity, as indication of clogging in these model ATES systems. The results showed no increase in upstream pressure during the period of enhanced biological activity (after lactate addition) under both flow rates, while the addition of nitrate lead to significant buildup of the pressure drop. However, at the flow rate of 10mL/min, high pressure buildup caused by nitrate addition could be alleviated by lactate addition. This indicates that the risk of biological clogging is relatively small in the investigated areas of the mimicked ATES system that combines enhanced bioremediation with lactate as substrate, and furthermore that lactate may counter chemical clogging. Copyright © 2017 Elsevier B.V. All rights reserved.

Semifield testing of a bioremediation tool for atrazine-contaminated soils: evaluating the efficacy on soil and aquatic compartments.

PubMed

Chelinho, Sónia; Moreira-Santos, Matilde; Silva, Cátia; Costa, Catarina; Viana, Paula; Viegas, Cristina A; Fialho, Arsénio M; Ribeiro, Rui; Sousa, José Paulo

2012-07-01

The present study evaluated the bioremediation efficacy of a cleanup tool for atrazine-contaminated soils (Pseudomonas sp. ADP plus citrate [P. ADP + CIT]) at a semifield scale, combining chemical and ecotoxicological information. Three experiments representing worst-case scenarios of atrazine contamination for soil, surface water (due to runoff), and groundwater (due to leaching) were performed in laboratory simulators (100 × 40 × 20 cm). For each experiment, three treatments were set up: bioremediated, nonbioremediated, and a control. In the first, the soil was sprayed with 10 times the recommended dose (RD) for corn of Atrazerba and with P. ADP + CIT at day 0 and a similar amount of P. ADP at day 2. The nonbioremediated treatment consisted of soil spraying with 10 times the RD of Atrazerba (day 0). After 7 d of treatment, samples of soil (and eluates), runoff, and leachate were collected for ecotoxicological tests with plants (Avena sativa and Brassica napus) and microalgae (Pseudokirchneriella subcapitata) species. In the nonbioremediated soils, atrazine was very toxic to both plants, with more pronounced effects on plant growth than on seed emergence. The bioremediation tool annulled atrazine toxicity to A. sativa (86 and 100% efficacy, respectively, for seed emergence and plant growth). For B. napus, results point to incomplete bioremediation. For the microalgae, eluate and runoff samples from the nonbioremediated soils were extremely toxic; a slight toxicity was registered for leachates. After only 7 d, the ecotoxicological risk for the aquatic compartments seemed to be diminished with the application of P. ADP + CIT. In aqueous samples obtained from the bioremediated soils, the microalgal growth was similar to the control for runoff samples and slightly lower than control (by 11%) for eluates. Copyright © 2012 SETAC.

Bioremediation potential of diesel-contaminated Libyan soil.

PubMed

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

2016-11-01

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

Evaluation of biostimulation and Tween 80 addition for the bioremediation of long-term DDT-contaminated soil.

PubMed

Betancur-Corredor, Bibiana; Pino, Nancy J; Cardona, Santiago; Peñuela, Gustavo A

2015-02-01

The bioremediation of a long-term contaminated soil through biostimulation and surfactant addition was evaluated. The concentrations of 1,1,1-trichloro-2,2-bis(4-chlorophenyl) ethane (DDT) and its metabolites 1,1-dichloro-2,2-bis(4-chlorophenyl) ethane (DDD) and 1,1-dichloro-2,2-bis(4-chlorophenyl) ethylene (DDE) were monitored during an 8-week remediation process. Physicochemical characterization of the treated soil was performed before and after the bioremediation process. The isolation and identification of predominant microorganisms during the remediation process were also carried out. The efficiency of detoxification was evaluated after each bioremediation protocol. Humidity and pH and the heterotrophic microorganism count were monitored weekly. The DDT concentration was reduced by 79% after 8 weeks via biostimulation with surfactant addition (B+S) and 94.3% via biostimulation alone (B). Likewise, the concentrations of the metabolites DDE and DDD were reduced to levels below the quantification limits. The microorganisms isolated during bioremediation were identified as Bacillus thuringiensis, Flavobacterium sp., Cuprivadius sp., Variovorax soli, Phenylobacterium sp. and Lysobacter sp., among others. Analysis with scanning electron microscopy (SEM) allowed visualization of the colonization patterns of soil particles. The toxicity of the soil before and after bioremediation was evaluated using Vibrio fischeri as a bioluminescent sensor. A decrease in the toxic potential of the soil was verified by the increase of the concentration/effect relationship EC50 to 26.9% and 27.2% for B+S and B, respectively, compared to 0.4% obtained for the soil before treatment and 2.5% by natural attenuation after 8 weeks of treatment. Copyright © 2014. Published by Elsevier B.V.

Impact of organic carbon and nutrients mobilized during chemical oxidation on subsequent bioremediation of a diesel-contaminated soil.

PubMed

Sutton, Nora B; Grotenhuis, Tim; Rijnaarts, Huub H M

2014-02-01

Remediation with in situ chemical oxidation (ISCO) impacts soil organic matter (SOM) and the microbial community, with deleterious effects on the latter being a major hurdle to coupling ISCO with in situ bioremediation (ISB). We investigate treatment of a diesel-contaminated soil with Fenton's reagent and modified Fenton's reagent coupled with a subsequent bioremediation phase of 187d, both with and without nutrient amendment. Chemical oxidation mobilized SOM into the liquid phase, producing dissolved organic carbon (DOC) concentrations 8-16 times higher than the untreated field sample. Higher aqueous concentrations of nitrogen and phosphorous species were also observed following oxidation; NH4(+) increased 14-172 times. During the bioremediation phase, dissolved carbon and nutrient species were utilized for microbial growth-yielding DOC concentrations similar to field sample levels within 56d of incubation. In the absence of nutrient amendment, the highest microbial respiration rates were correlated with higher availability of nitrogen and phosphorus species mobilized by oxidation. Significant diesel degradation was only observed following nutrient amendment, implying that nutrients mobilized by chemical oxidation can increase microbial activity but are insufficient for bioremediation. While all bioremediation occurred in the first 28d of incubation in the biotic control microcosm with nutrient amendment, biodegradation continued throughout 187d of incubation following chemical oxidation, suggesting that chemical treatment also affects the desorption of organic contaminants from SOM. Overall, results indicate that biodegradation of DOC, as an alternative substrate to diesel, and biological utilization of mobilized nutrients have implications for the success of coupled ISCO and ISB treatments. Copyright © 2013 Elsevier Ltd. All rights reserved.

Revealing potential functions of VBNC bacteria in polycyclic aromatic hydrocarbons biodegradation.

PubMed

Su, X M; Bamba, A M; Zhang, S; Zhang, Y G; Hashmi, M Z; Lin, H J; Ding, L X

2018-04-01

The bioremediation of polycyclic aromatic hydrocarbon (PAH)-contaminated sites is not running smoothly, because of the lower activity of PAH-degrading bacteria in actual bioremediation applications. The phenomenon of "viable but nonculturable" (VBNC) state may be a main limiting factor for their poor biodegradation capabilities of PAHs. Due to their abilities of entering into the VBNC state, most of bacterial populations with PAH-degradation potential remain unculturable. Resuscitation of VBNC bacteria will enhance the degradation capability of indigenous bacteria which will eventually obtain their better capabilities in environmental bioremediation. Although evidences have been presented indicating that resuscitation of VBNC bacteria in polychlorinated biphenyl (PCB)-contaminated environments not only significantly enhanced PCB degradation, but also obtained novel highly efficient PCB-degrading bacteria, scanty information is available on the VBNC bacteria in PAH-contaminated sites. VBNC bacteria, as a vast majority of potential microbial resource could be the repository of novel highly efficient PAH-biodegraders. Therefore, studies need to be done on resuscitation of VBNC bacteria to overcome key bottlenecks in bioremediation of PAH-contaminated sites. This mini-review provides a new insight into the potential functions of VBNC bacteria in PAHs biodegradation. As the vast majority microbial resource, viable but nonculturable (VBNC) bacteria, which showed their potential functions in polycyclic aromatic hydrocarbons (PAHs) biodegradation, can be of great significance in environmental bioremediation. It is therefore important to resuscitate VBNC bacteria for their better capabilities. Meanwhile, preventing the indigenous functional community from entering into the VBNC state will also maintain the high activity of PAH-degrading bacteria in actual bioremediation applications. Undoubtedly, much more work needs to be done to reveal indigenous micro-organisms in the VBNC state from the perspective of environmental functions. © 2018 The Society for Applied Microbiology.

DEMONSTRATION BULLETIN: EX-SITU ANAEROBIC BIOREMEDIATION SYSTEM: DINOSEB - J.R. SIMPLOT COMPANY

EPA Science Inventory

The J.R. Simplot Ex-situ Anaerobic Bioremediation System is a technology designed to destroy nitroaromatic compounds without forming any toxic intermediates. The nitroaromatic compound of interest during this demonstration was dinoseb (2-sec-butyl-4,6-dinitrophenol) an agricul...

SITE TECHNOLOGY CAPSULE: J.R. SIMPLOT EX-SITU ANAEROBIC BIOREMEDIATION TECHNOLOGY: TNT

EPA Science Inventory

The J.R. Simplot Ex-Situ Bioremediation Technology is designed to degrade nitroaromatic compounds anaerobically, with total destruction of toxic intermediates at the completion of treatment. An evaluation of this technology was conducted under the SITE Program on TNT-contaminated...

UTILIZATION OF TREATABILITY AND PILOT TESTS TO PREDICT CAH BIOREMEDIATION (Battelle)

EPA Science Inventory

Multiple tools have been suggested to help in the design of enhanced anaerobic bioremediation systems for CAHs:
Extensive high quality microcosm testing followed by small-scale, thoroughly observed, induced flow field pilot tests (i.e. RABITT Protocol, Morse 1998)
More...

LABORATORY EVALUATION OF OIL SPILL BIOREMEDIATION PRODUCTS IN SALT AND FRESHWATER SYSTEMS

EPA Science Inventory

Ten oil spill bioremediation products were tested in the laboratory for their ability to enhance biodegradation of weathered Alaskan North Slope crude oil in both fresh and salt-water media. The products included: nutrients to stimulate inoculated microorganisms, nutrients plus a...

In Situ Bioremediation of Perchlorate in Vadose Zone Source Areas

DTIC Science & Technology

2011-01-01

agricultural bags (e.g., ITRC, 2008; Evans et al., 2008). Phytoremediation has also been tested for soil treatment (ITRC, 2008). However, these...within the saturated zone (through in situ bioremediation or groundwater extraction and ex-situ treatment), phytoremediation , which is unlikely to

NUTRIENT TRANSPORT DURING BIOREMEDIATION OF CONTAMINATED BEACHES: EVALUATION WITH LITHIUM AS A CONSERVATIVE TRACER

EPA Science Inventory

Bioremediation of oil-contaminated beaches typically involves fertilization with nutrients that are thought to limit the growth rate of hydrocarbon-degrading bacteria. Much of the available technology involves application of fertilizers that release nutrients in a water-soluble ...

NATURAL BIOREMEDIATION PERSPECTIVE FOR BTX CONTAMINATED GROUNDWATER IN BRAZIL: EFFECT OF ETHANOL (R823420)

EPA Science Inventory

Abstract

Natural bioremediation, the use of indigenous microorganisms to degrade hazardous substances within aquifers without engineered stimulation, shows great promise as a cost-effective approach to hydrocarbon plume management. This technique requires thorough site...

SABRE MULTI-LAB, STATISTICALLY-BASED MICROCOSM STUDY FOR TCE SOURCE ZONE REMEDIATION (ABSTRACT ONLY)

EPA Science Inventory

SABRE (source area bioremediation) is a public/private consortium of twelve companies, two government agencies, and three research institutions whose charter is to determine if enhanced anaerobic bioremediation can result in effective and quantifiable treatment of chlorinated sol...

TRANSECT STUDY OF THE INTRINSIC BIOREMEDIATION TEST PLOT: DOVER AFB

EPA Science Inventory

The work described in this report is part of a project undertaken by the Bioremediation of Chlorinated Solvents Action Team of the Remediation Technologies Development Forum, a joint U.S. Federal agency-industry collaboration, to study the natural attenuation of chlorinated ethen...

STUDIES ON BIOREMEDIATION OF POLYCYCLIC AROMATIC HYDROCARBON-CONTAMINATED SEDIMENTS: BIOAVAILABILITY, BIODEGRADABILITY, AND TOXICITY ISSUES

EPA Science Inventory

The widespread contamination of aquatic sediments by polycyclic aromatic hydrocarbons (PAHs) has created a need for cost-effective bioremediation processes, on which the bioavailability and the toxicity of PAHs often have a significant impact. This research investigated the biode...

INTRINSIC BIOREMEDIATION OF A PETROLEUM-IMPACTED WETLAND

EPA Science Inventory

Following the 1994 San Jacinto River flood and oil spill in southeast Texas, a petroleum-contaminated wetland was reserved for a long-term research program to evaluate bioremediation as a viable spill response tool. The first phase of this program, presented in this paper, evalua...

BIOREMEDIATION OF HAZARDOUS WASTES - RESEARCH, DEVELOPMENT, AND FIELD EVALUATIONS - 1994

EPA Science Inventory

The proceedings of the 1994 Symposium on Bioremediation of Hazardous Wastes, hosted by the Office of Research and Development (ORD) of the EPA in San Francisco, California. The symposium was the seventh annual meeting for the presentation of research conducted by EPA's Biosystem...

EFFECTIVENESS AND SAFETY OF STRATEGIES FOR OIL SPILL BIOREMEDIATION: POTENTIAL AND LIMITATION, LABORATORY TO FIELD (RESEARCH BRIEF)

EPA Science Inventory

Several important additional research efforts were identified during the development of test systems and protocols for assessing the effectiveness and environmental safety of oil spill commercial bioremediation agents (CBAs). Research that examined CBA efficacy issues included: (...

DESIGN AND OPERATION OF A HORIZONTAL WELL, IN SITU BIOREMEDIATION SYSTEM

EPA Science Inventory

A large field demonstration using nutrient addition to stimulate insitu anaerobic bioremediation of chlorinated solvent contaminated soil and ground water was performed at the former U.S. Department of Energy Pinellas Plant in Largo, Florida, from January through June, 1997. Ins...

CONTAMINANT REDISTRIBUTION CAN CONFOUND INTERPRETATION OF OIL-SPILL BIOREMEDIATION STUDIES

EPA Science Inventory

The physical redistribution of oil between the inside and outside of experimental plots can affect the results of bioremediation field studies that are conducted on shorelines contaminated by real oil spills. Because untreated oil from the surrounding beach will enter the plot, ...

[Anoxic bioremediation of urban polluted river water with biofilm].

PubMed

Zhang, Yong-Ming; Hu, Yi-Zhen; Yan, Rong; Liu, Fang

2009-07-15

Reactor like oxidation ditch was used for anaerobic bioremediation of urban river water, in which biofilm formed on ceramic honeycomb carrier was used instated of activated sludge. The dissolved oxygen in the wastewater was controlled under 0.5 mg/L for anoxic oxidation, and ammonia nitrogen was removed 40 to 60 percent, and total nitrogen removed 40 to 45 percent, that is ammonia nitrogen and total nitrogen were removed at the same time, also, nitrite was not any accumulated during the process. The biofilm was taken into flask to culture under anoxic oxidation condition in order to prove if anaerobic ammonium oxidation (ANAMMOX) occurred in the process, and ammonia and nitrite nitrogen were also removed at the same time in the experiment, which suggested that nitrification-denitrification and ANAMMOX occurred in bioremediation of urban surface water with low ratio of carbon and nitrogen at the same time. The anammox bacteria were existed in the biofilm according to molecular biological analysis. The experiment will be significant for bioremediation of eutrophication water body.

Soil and brownfield bioremediation.

PubMed

Megharaj, Mallavarapu; Naidu, Ravi

2017-09-01

Soil contamination with petroleum hydrocarbons, persistent organic pollutants, halogenated organic chemicals and toxic metal(loid)s is a serious global problem affecting the human and ecological health. Over the past half-century, the technological and industrial advancements have led to the creation of a large number of brownfields, most of these located in the centre of dense cities all over the world. Restoring these sites and regeneration of urban areas in a sustainable way for beneficial uses is a key priority for all industrialized nations. Bioremediation is considered a safe economical, efficient and sustainable technology for restoring the contaminated sites. This brief review presents an overview of bioremediation technologies in the context of sustainability, their applications and limitations in the reclamation of contaminated sites with an emphasis on brownfields. Also, the use of integrated approaches using the combination of chemical oxidation and bioremediation for persistent organic pollutants is discussed. © 2017 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Innovative encapsulated oxygen-releasing beads for bioremediation of BTEX at high concentration in groundwater.

PubMed

Lin, Chi-Wen; Wu, Chih-Hung; Guo, Pei-Yu; Chang, Shih-Hsien

2017-12-15

Both a low concentration of dissolved oxygen and the toxicity of a high concentration of BTEX inhibit the bioremediation of BTEX in groundwater. A novel method of preparing encapsulated oxygen-releasing beads (encap-ORBs) for the biodegradation of BTEX in groundwater was developed. Experimental results show that the integrality and oxygen-releasing capacity of encap-ORBs exceeded those of ORBs. The use of polyvinyl alcohol (PVA) with high M.W. to prepare encap-ORBs improved their integrality. The encap-ORBs effectively released oxygen for 128 days. High concentration of BTEX (480 mg L -1 ) inhibited the biodegradation by the free cells. Immobilization of degraders in the encap-ORB alleviated the inhibition. Scanning electron microscope analysis reveals that the BTEX degraders grew on the surface of encap-ORB after bioremediation. The above results indicate that the encap-ORBs were effective in the bioremediation of BTEX at high concentration in groundwater. Copyright © 2017 Elsevier Ltd. All rights reserved.

Uranium plume persistence impacted by hydrologic and geochemical heterogeneity in the groundwater and river water interaction zone of Hanford site

NASA Astrophysics Data System (ADS)

Chen, X.; Zachara, J. M.; Vermeul, V. R.; Freshley, M.; Hammond, G. E.

2015-12-01

The behavior of a persistent uranium plume in an extended groundwater- river water (GW-SW) interaction zone at the DOE Hanford site is dominantly controlled by river stage fluctuations in the adjacent Columbia River. The plume behavior is further complicated by substantial heterogeneity in physical and geochemical properties of the host aquifer sediments. Multi-scale field and laboratory experiments and reactive transport modeling were integrated to understand the complex plume behavior influenced by highly variable hydrologic and geochemical conditions in time and space. In this presentation we (1) describe multiple data sets from field-scale uranium adsorption and desorption experiments performed at our experimental well-field, (2) develop a reactive transport model that incorporates hydrologic and geochemical heterogeneities characterized from multi-scale and multi-type datasets and a surface complexation reaction network based on laboratory studies, and (3) compare the modeling and observation results to provide insights on how to refine the conceptual model and reduce prediction uncertainties. The experimental results revealed significant spatial variability in uranium adsorption/desorption behavior, while modeling demonstrated that ambient hydrologic and geochemical conditions and heterogeneities in sediment physical and chemical properties both contributed to complex plume behavior and its persistence. Our analysis provides important insights into the characterization, understanding, modeling, and remediation of groundwater contaminant plumes influenced by surface water and groundwater interactions.

Simplified behaviors from increased heterogeneity: II. 3-D uranium transport at the decimeter scale and intertank comparisons.

PubMed

Miller, Andrew W; Rodriguez, Derrick R; Honeyman, Bruce D

2013-05-01

Upscaling from bench scale systems to field scale systems incorporates physical and chemical heterogeneities from atomistic up to field scales. Heterogeneities of intermediate scale (~10(-1) m) are impossible to incorporate in a bench scale experiment. To transcend these scale discrepancies, this second in a pair of papers presents results from an intermediate scale, 3-D tank experiment completed using five different particle sizes of uranium contaminated sediment from a former uranium mill field site. The external dimensions of the tank were 2.44 m×0.61 m×0.61 m (L×H×W). The five particle sizes were packed in a heterogeneous manner using roughly 11 cm cubes. Small groundwater wells were installed for spatial characterization of chemical gradients and flow parameters. An approximately six month long bromide tracer test was used for flow field characterization. Within the flow domain, local uranium breakthrough curves exhibited a wide range of behaviors. However, the global effluent breakthrough curve was smooth, and not unlike breakthrough curves observed in column scale experiments. This paper concludes with an inter-tank comparison of all three experimental systems presented in this pair of papers. Although there is a wide range of chemical and physical variability between the three tanks, major chemical constituent behaviors are often quite similar or even identical. Copyright © 2013 Elsevier B.V. All rights reserved.

Evaluating bioremediation: distinguishing fact from fiction.

PubMed

Shannon, M J; Unterman, R

1993-01-01

Bioremediation options encompass diverse types of biochemical mechanisms that may lead to a target's mineralization, partial transformation, humification, or altered redox state (e.g. for metallic elements). Because these various mechanisms produce alternative fates of the targeted pollutants, it is often necessary to use diverse evaluation criteria to qualify a successful bioremediation. Too often target depletion from a treated matrix can be mistakenly ascribed to biological activity when in fact the depletion is caused by abiotic losses (e.g. volatilization, leaching, and stripping). Thus, effective, and therefore convincing, evaluation requires that experimental and engineering designs anticipate all possible routes of target depletion and that these routes be carefully monitored.

Bioremediation of Industrial Waste Through Enzyme Producing Marine Microorganisms.

PubMed

Sivaperumal, P; Kamala, K; Rajaram, R

Bioremediation process using microorganisms is a kind of nature-friendly and cost-effective clean green technology. Recently, biodegradation of industrial wastes using enzymes from marine microorganisms has been reported worldwide. The prospectus research activity in remediation area would contribute toward the development of advanced bioprocess technology. To minimize industrial wastes, marine enzymes could constitute a novel alternative in terms of waste treatment. Nowadays, the evidence on the mechanisms of bioremediation-related enzymes from marine microorganisms has been extensively studied. This review also will provide information about enzymes from various marine microorganisms and their complexity in the biodegradation of comprehensive range of industrial wastes. © 2017 Elsevier Inc. All rights reserved.

Using Iron to Treat Chlorohydrocarbon-Contaminated Soil

NASA Technical Reports Server (NTRS)

Hitchens, G. Duncan; Hodko, Dalibor; Kim, Heekyung; Rogers, Tom; Singh, Waheguru Pal; Giletto, Anthony; Cisar, Alan

2004-01-01

A method of in situ remediation of soil contaminated with chlorinated hydrocarbon solvents involves injection of nanometer-size iron particles. The present method exploits a combination of prompt chemical remediation followed by longer-term enhanced bioremediation and, optionally, is practiced in conjunction with the method of bioremediation described earlier. Newly injected iron particles chemically reduce chlorinated hydrocarbons upon contact. Thereafter, in the presence of groundwater, the particles slowly corrode via chemical reactions that effect sustained release of dissolved hydrogen. The hydrogen serves as an electron donor, increasing the metabolic activity of the anaerobic bacteria and thereby sustaining bioremediation at a rate higher than the natural rate.

Ex-situ bioremediation of crude oil in soil, a comparative kinetic analysis.

PubMed

Mohajeri, Leila; Aziz, Hamidi Abdul; Isa, Mohamed Hasnain; Zahed, Mohammad Ali; Mohajeri, Soraya

2010-07-01

Weathered crude oil (WCO) removals in shoreline sediment samples were monitored for 60 days in bioremediation experimentation. Experimental modeling was carried out using statistical design of experiments. At optimum conditions maximum of 83.13, 78.06 and 69.92% WCO removals were observed for 2, 16 and 30 g/kg initial oil concentrations, respectively. Significant variations in the crude oil degradation pattern were observed with respect to oil, nutrient and microorganism contents. Crude oil bioremediation were successfully described by a first-order kinetic model. The study indicated that the rate of hydrocarbon biodegradation increased with decrease of crude oil concentrations.

Selected field and analytical methods and analytical results in the Dutch Flats area, western Nebraska, 1995-99

USGS Publications Warehouse

Verstraeten, Ingrid M.; Steele, G.V.; Cannia, J.C.; Bohlke, J.K.; Kraemer, T.E.; Hitch, D.E.; Wilson, K.E.; Carnes, A.E.

2001-01-01

A study of the water resources of the Dutch Flats area in the western part of the North Platte Natural Resources District, western Nebraska, was conducted from 1995 through 1999 to describe the surface water and hydrogeology, the spatial distribution of selected water-quality constituents in surface and ground water, and the surface-water/ground-water interaction in selected areas. This report describes the selected field and analytical methods used in the study and selected analytical results from the study not previously published. Specifically, dissolved gases, age-dating data, and other isotopes collected as part of an intensive sampling effort in August and November 1998 and all uranium and uranium isotope data collected through the course of this study are included in the report.

AQUIFER PROTIST RESPONSE AND THE POTENTIAL FOR TCE BIOREMEDIATION WITH BURKHOLDERIA CEPACIA G4 PR1

EPA Science Inventory

The introduction of bacteria into the environment for bioremediation purposes (bioaugmentation) requires analysis and monitoring of the persistence and activity of microbial population for efficacy and risk assessment purposes. Burkholderia cepacia G4 PR123 and PR131 constitutive...

BIOREMEDIATION OF HAZARDOUS WASTES - RESEARCH, DEVELOPMENT, AND FIELD EVALUATIONS - 1993

EPA Science Inventory

The proceedings of the 1993 Symposium on Bioremediation of Hazardous Wastes, hosted by the Office of Research and Development (ORD) of the EPA in Dallas, Texas The symposium was the sixth annual meeting for the presentation of research conducts (by EPA's Biosystems Technology Dev...

ENHANCED BIOREMEDIATION UTILIZING HYDROGEN PEROXIDE AS A SUPPLEMENTAL SOURCE OF OXYGEN: A LABORATORY AND FIELD STUDY

EPA Science Inventory

Laboratory and field scale studies were conducted to investigate the feasibility of using hydrogen peroxide as a supplemental source of oxygen for bioremediation of an aviation gasoline fuel spill. Field samples of aviation gasoline contaminated aquifer material were artificially...

DEMONSTRATION BULLETIN: EX-SITU ANAEROBIC BIOREMEDIATION TECHNOLOGY - TNT - J.R. SIMPLOT COMPANY

EPA Science Inventory

The J. R. Simplot Ex-Situ Anaerobic Bioremediation System, also known as the J.R. Simplot Anaerobic Biological Remediaton Process (the SABRE™ Process), is a technology designed to destroy nitroaromatic and energetic compounds. The process does not evolve any known toxic intermedi...

BIOINSPIRED DESIGN AND DIRECTED EVOLUTION OF IRON CONTAINING ENZYMES FOR GREENSYNTHETIC PROCESSES AND BIOREMEDIATION

EPA Science Inventory

SU833912
Title: Bioinspired Design and Directed Evolution of Iron Containing Enzymes for Green Synthetic Processes and BioremediationEdward I. Solomon, Shaun D. Wong, Lei Liu, Caleb B. Bell, IIICynthia Nolt-Helms
Project Period: August 15, 2008 - August 14,...

EVALUATION OF BIOREMEDIATION STRATEGIES OF A CONTROLLED OIL RELEASE IN A WETLAND

EPA Science Inventory

A controlled petroleum release was conducted to evaluate bioremediation in a wetland near Houston, Texas. The 140-day study was conducted using a randomized, complete block design to test three treatments with six replicates per treatment. The three treatment strategies were in...

GUIDELINES FOR THE BIOREMEDIATION OF OIL-CONTAMINATED SALT MARSHES

EPA Science Inventory

The objective of this document is to present a detailed technical guideline for use by spill responders for the cleanup of coastal wetlands contaminated with oil and oil products by using one of the least intrusive approaches
bioremediation technology. This manual is a supplem...

BIOREMEDIATION OF HAZARDOUS WASTES - RESEARCH, DEVELOPMENT AND FIELD EVALUATIONS - 1995

EPA Science Inventory

The proceedings of the 1995 Symposium on Bioremediation of Hazardous Wastes, hosted by the Office of Research and Development (ORD) of the EPA in Rye Brook, New York. he symposium was the eighth annual meeting for the presentation of research conducted by EPA's Biosystems Technol...

SITE DEMONSTRATION BULLETIN - ENHANCED IN-SITU BIOREMEDIATION PROCESS, EARTH TECH, INC.

EPA Science Inventory

The USEPA conducted an evaluation of the Enhanced In-situ Bioremediation process, a biostimulation technology developed by the USDOE at the Westinghouse Savannah River Plant site in Aiken, SC. DOE has licensed the process to Earth Tech, Inc. The evaluation described in this bulle...

EFFECT OF NITRATE-BASED BIOREMEDIATION ON CONTAMINANT DISTRIBUTION AND SEDIMENT TOXICITY-COLUMN STUDY

EPA Science Inventory

A laboratory column study was set up to evaluate changes in contaminant distribution and sediment toxicity following nitrate-based bioremediation and to correlate toxicity reduction with loss of fuel components. Glass columns were packed with sediment from an aquifer that had be...

A review on slurry bioreactors for bioremediation of soils and sediments.

PubMed

Robles-González, Ireri V; Fava, Fabio; Poggi-Varaldo, Héctor M

2008-02-29

The aim of this work is to present a critical review on slurry bioreactors (SB) and their application to bioremediation of soils and sediments polluted with recalcitrant and toxic compounds. The scope of the review encompasses the following subjects: (i) process fundamentals of SB and analysis of advantages and disadvantages; (ii) the most recent applications of SB to laboratory scale and commercial scale soil bioremediation, with a focus on pesticides, explosives, polynuclear aromatic hydrocarbons, and chlorinated organic pollutants; (iii) trends on the use of surfactants to improve availability of contaminants and supplementation with degradable carbon sources to enhance cometabolism of pollutants; (iv) recent findings on the utilization of electron acceptors other than oxygen; (v) bioaugmentation and advances made on characterization of microbial communities of SB; (vi) developments on ecotoxicity assays aimed at evaluating bioremediation efficiency of the process.From this review it can be concluded that SB is an effective ad situ and ex situ technology that can be used for bioremediation of problematic sites, such as those characterized by soils with high contents of clay and organic matter, by pollutants that are recalcitrant, toxic, and display hysteretic behavior, or when bioremediation should be accomplished in short times under the pressure and monitoring of environmental agencies and regulators. SB technology allows for the convenient manipulation and control of several environmental parameters that could lead to enhanced and faster treatment of polluted soils: nutrient N, P and organic carbon source (biostimulation), inocula (bioaugmentation), increased availability of pollutants by use of surfactants or inducing biosurfactant production inside the SB, etc. An interesting emerging area is the use of SB with simultaneous electron acceptors, which has demonstrated its usefulness for the bioremediation of soils polluted with hydrocarbons and some organochlorinated compounds. Characterization studies of microbial communities of SB are still in the early stages, in spite of their significance for improving reactor operation and design optimization.We have identified the following niches of research needs for SB in the near and mid term future, inter alia: (i) application of SB with sequential and simultaneous electron acceptors to soils polluted with contaminants other than hydrocarbons (i.e., pesticides, explosives, etc.), (ii) evaluation of the technical feasibility of triphasic SB that use innocuous solvents to help desorbing pollutants strongly attached to soils, and in turn, to enhance their biodegradation, (iii) gaining deeper insight of microbial communities present in SB with the intensified application of molecular biology tools such as PCR-DGGE, PCR-TGGE, ARDRA, etc., (iv) development of more representative ecotoxicological assays to better assess the effectiveness of a given bioremediation process.

Impact of Groundwater Salinity on Bioremediation Enhanced by Micro-Nano Bubbles

PubMed Central

Li, Hengzhen; Hu, Liming; Xia, Zhiran

2013-01-01

Micro-nano bubbles (MNBs) technology has shown great potential in groundwater bioremediation because of their large specific surface area, negatively charged surface, long stagnation, high oxygen transfer efficiency, etc. Groundwater salinity, which varies from sites due to different geological and environmental conditions, has a strong impact on the bioremediation effect. However, the groundwater salinity effect on MNBs’ behavior has not been reported. In this study, the size distribution, oxygen transfer efficiency and zeta potential of MNBs was investigated in different salt concentrations. In addition, the permeability of MNBs’ water through sand in different salt concentrations was studied. The results showed that water salinity has no influence on bubble size distribution during MNBs generation. MNBs could greatly enhance the oxygen transfer efficiency from inner bubbles to outer water, which may greatly enhance aerobic bioremediation. However, the enhancement varied depending on salt concentration. 0.7 g/L was found to be the optimal salt concentration to transfer oxygen. Moreover, MNBs in water salinity of 0.7 g/L had the minimum zeta potential. The correlation of zeta potential and mass transfer was discussed. The hydraulic conductivities of sand were similar for MNBs water with different salt concentrations. The results suggested that salinity had a great influence on MNBs performance, and groundwater salinity should be taken into careful consideration in applying MNBs technology to the enhancement of bioremediation. PMID:28788299

Electromigration of Contaminated Soil by Electro-Bioremediation Technique

NASA Astrophysics Data System (ADS)

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

2016-07-01

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

Effect of alternating bioremediation and electrokinetics on the remediation of n-hexadecane-contaminated soil

NASA Astrophysics Data System (ADS)

Wang, Sa; Guo, Shuhai; Li, Fengmei; Yang, Xuelian; Teng, Fei; Wang, Jianing

2016-04-01

This study demonstrated the highly efficient degradation of n-hexadecane in soil, realized by alternating bioremediation and electrokinetic technologies. Using an alternating technology instead of simultaneous application prevented competition between the processes that would lower their efficiency. For the consumption of the soil dissolved organic matter (DOM) necessary for bioremediation by electrokinetics, bioremediation was performed first. Because of the utilization and loss of the DOM and water-soluble ions by the microbial and electrokinetic processes, respectively, both of them were supplemented to provide a basic carbon resource, maintain a high electrical conductivity and produce a uniform distribution of ions. The moisture and bacteria were also supplemented. The optimal DOM supplement (20.5 mg·kg-1 glucose; 80-90% of the total natural DOM content in the soil) was calculated to avoid competitive effects (between the DOM and n-hexadecane) and to prevent nutritional deficiency. The replenishment of the water-soluble ions maintained their content equal to their initial concentrations. The degradation rate of n-hexadecane was only 167.0 mg·kg-1·d-1 (1.9%, w/w) for the first 9 days in the treatments with bioremediation or electrokinetics alone, but this rate was realized throughout the whole process when the two technologies were alternated, with a degradation of 78.5% ± 2.0% for the n-hexadecane after 45 days of treatment.

Sustainable Sources of Biomass for Bioremediation of Heavy Metals in Waste Water Derived from Coal-Fired Power Generation

PubMed Central

Saunders, Richard J.; Paul, Nicholas A.; Hu, Yi; de Nys, Rocky

2012-01-01

Biosorption of heavy metals using dried algal biomass has been extensively described but rarely implemented. We contend this is because available algal biomass is a valuable product with a ready market. Therefore, we considered an alternative and practical approach to algal bioremediation in which algae were cultured directly in the waste water stream. We cultured three species of algae with and without nutrient addition in water that was contaminated with heavy metals from an Ash Dam associated with coal-fired power generation and tested metal uptake and bioremediation potential. All species achieved high concentrations of heavy metals (to 8% dry mass). Two key elements, V and As, reached concentrations in the biomass of 1543 mg.kg−1 DW and 137 mg.kg−1 DW. Growth rates were reduced by more than half in neat Ash Dam water than when nutrients were supplied in excess. Growth rate and bioconcentration were positively correlated for most elements, but some elements (e.g. Cd, Zn) were concentrated more when growth rates were lower, indicating the potential to tailor bioremediation depending on the pollutant. The cosmopolitan nature of the macroalgae studied, and their ability to grow and concentrate a suite of heavy metals from industrial wastes, highlights a clear benefit in the practical application of waste water bioremediation. PMID:22590550

Bioremediation of weathered petroleum hydrocarbon soil contamination in the Canadian High Arctic: laboratory and field studies.

PubMed

Sanscartier, David; Laing, Tamsin; Reimer, Ken; Zeeb, Barbara

2009-11-01

The bioremediation of weathered medium- to high-molecular weight petroleum hydrocarbons (HCs) in the High Arctic was investigated. The polar desert climate, contaminant characteristics, and logistical constraints can make bioremediation of persistent HCs in the High Arctic challenging. Landfarming (0.3 m(3) plots) was tested in the field for three consecutive years with plots receiving very little maintenance. Application of surfactant and fertilizers, and passive warming using a greenhouse were investigated. The field study was complemented by a laboratory experiment to better understand HC removal mechanisms and limiting factors affecting bioremediation on site. Significant reduction of total petroleum HCs (TPH) was observed in both experiments. Preferential removal of compounds nC16 occurred, whereas in the field, TPH reduction was mainly limited to removal of compounds nC16 was observed in the fertilized field plots only. The greenhouse increased average soil temperatures and extended the treatment season but did not enhance bioremediation. Findings suggest that temperature and low moisture content affected biodegradation of HCs in the field. Little volatilization was measured in the laboratory, but this process may have been predominant in the field. Low-maintenance landfarming may be best suited for remediation of HCs compounds

Ecogenomics of microbial communities in bioremediation of chlorinated contaminated sites

PubMed Central

Maphosa, Farai; Lieten, Shakti H.; Dinkla, Inez; Stams, Alfons J.; Smidt, Hauke; Fennell, Donna E.

2012-01-01

Organohalide compounds such as chloroethenes, chloroethanes, and polychlorinated benzenes are among the most significant pollutants in the world. These compounds are often found in contamination plumes with other pollutants such as solvents, pesticides, and petroleum derivatives. Microbial bioremediation of contaminated sites, has become commonplace whereby key processes involved in bioremediation include anaerobic degradation and transformation of these organohalides by organohalide respiring bacteria and also via hydrolytic, oxygenic, and reductive mechanisms by aerobic bacteria. Microbial ecogenomics has enabled us to not only study the microbiology involved in these complex processes but also develop tools to better monitor and assess these sites during bioremediation. Microbial ecogenomics have capitalized on recent advances in high-throughput and -output genomics technologies in combination with microbial physiology studies to address these complex bioremediation problems at a system level. Advances in environmental metagenomics, transcriptomics, and proteomics have provided insights into key genes and their regulation in the environment. They have also given us clues into microbial community structures, dynamics, and functions at contaminated sites. These techniques have not only aided us in understanding the lifestyles of common organohalide respirers, for example Dehalococcoides, Dehalobacter, and Desulfitobacterium, but also provided insights into novel and yet uncultured microorganisms found in organohalide respiring consortia. In this paper, we look at how ecogenomic studies have aided us to understand the microbial structures and functions in response to environmental stimuli such as the presence of chlorinated pollutants. PMID:23060869

Bioremediation of lead contaminated soil with Rhodobacter sphaeroides.

PubMed

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

2016-08-01

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

Bioremediation of Toxic Heavy Metals: A Patent Review.

PubMed

Verma, Neelam; Sharma, Rajni

2017-01-01

The global industrialization is fulfilling the demands of modern population at the cost of environmental exposure to various contaminants including heavy metals. These heavy metals affect water and soil quality. Moreover, these enter into the food chain and exhibit their lethal effects on the human health even when present at slightly higher concentration than required for normal metabolism. To the worst of their part, the heavy metals may become carcinogenic. Henceforth, the efficient removal of heavy metals is the demand of sustainable development. Remedy: Bioremediation is the 'green' imperative technique for the heavy metal removal without creating secondary metabolites in the ecosystem. The metabolic potential of several bacterial, algal, fungal as well as plant species has the efficiency to exterminate the heavy metals from the contaminated sites. Different strategies like bioaccumulation, biosorption, biotransformation, rhizofilteration, bioextraction and volatilization are employed for removal of heavy metals by the biological species. Bioremediation approach is presenting a splendid alternate for conventional expensive and inefficient methods for the heavy metal removal. The patents granted on the bioremediation of toxic heavy metals are summarized in the present manuscript which supported the applicability of bioremediation technique at commercial scale. However, the implementation of the present information and advanced research are mandatory to further explore the concealed potential of biological species to resume the originality of the environment. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Microbial Functional Gene Diversity Predicts Groundwater Contamination and Ecosystem Functioning.

PubMed

He, Zhili; Zhang, Ping; Wu, Linwei; Rocha, Andrea M; Tu, Qichao; Shi, Zhou; Wu, Bo; Qin, Yujia; Wang, Jianjun; Yan, Qingyun; Curtis, Daniel; Ning, Daliang; Van Nostrand, Joy D; Wu, Liyou; Yang, Yunfeng; Elias, Dwayne A; Watson, David B; Adams, Michael W W; Fields, Matthew W; Alm, Eric J; Hazen, Terry C; Adams, Paul D; Arkin, Adam P; Zhou, Jizhong

2018-02-20

Contamination from anthropogenic activities has significantly impacted Earth's biosphere. However, knowledge about how environmental contamination affects the biodiversity of groundwater microbiomes and ecosystem functioning remains very limited. Here, we used a comprehensive functional gene array to analyze groundwater microbiomes from 69 wells at the Oak Ridge Field Research Center (Oak Ridge, TN), representing a wide pH range and uranium, nitrate, and other contaminants. We hypothesized that the functional diversity of groundwater microbiomes would decrease as environmental contamination (e.g., uranium or nitrate) increased or at low or high pH, while some specific populations capable of utilizing or resistant to those contaminants would increase, and thus, such key microbial functional genes and/or populations could be used to predict groundwater contamination and ecosystem functioning. Our results indicated that functional richness/diversity decreased as uranium (but not nitrate) increased in groundwater. In addition, about 5.9% of specific key functional populations targeted by a comprehensive functional gene array (GeoChip 5) increased significantly ( P < 0.05) as uranium or nitrate increased, and their changes could be used to successfully predict uranium and nitrate contamination and ecosystem functioning. This study indicates great potential for using microbial functional genes to predict environmental contamination and ecosystem functioning. IMPORTANCE Disentangling the relationships between biodiversity and ecosystem functioning is an important but poorly understood topic in ecology. Predicting ecosystem functioning on the basis of biodiversity is even more difficult, particularly with microbial biomarkers. As an exploratory effort, this study used key microbial functional genes as biomarkers to provide predictive understanding of environmental contamination and ecosystem functioning. The results indicated that the overall functional gene richness/diversity decreased as uranium increased in groundwater, while specific key microbial guilds increased significantly as uranium or nitrate increased. These key microbial functional genes could be used to successfully predict environmental contamination and ecosystem functioning. This study represents a significant advance in using functional gene markers to predict the spatial distribution of environmental contaminants and ecosystem functioning toward predictive microbial ecology, which is an ultimate goal of microbial ecology. Copyright © 2018 He et al.

Bridging the gap between tribal risk perceptions and scientific decision-making for uranium legacy sites located in Native American communities

NASA Astrophysics Data System (ADS)

Joseph, C.; Waugh, W.; Glenn, E.; Chief, K.

2017-12-01

There are approximately 15,000 abandoned uranium mines (AUM) in the western United States, of which 500 AUMs are located in the Colorado Plateau Four-Corners region. Uranium mill tailings, referred to as legacy waste, compromise the largest volume of any category of radioactive waste in the nation. Today, the Department of Energy Legacy Management is responsible for long-term stewardship and maintenance of inactive uranium processing sites that have been remediated to prevent further migration and exposure of tailings to the environment and surrounding communities. In collaboration with the DOE-LM, I am investigating the impact of climate change and community adaptation on the long-term performance of disposal cell covers for uranium mill tailings located in Native American communities, as well as how these communities have adapted to and perceive these areas. I am interested in how abiotic engineered cell covers may be candidate sites for future conversion to vegetated evapotranspirative caps for arid to semi-arid climates. The objectives are to: 1) assess above-ground tissue of plants encroaching engineered cell covers for concentrations of uranium, radium, selenium, molybdenum, thorium, arsenic, lead, and manganese and compare them to control sites; 2) determine if above-cell plant tissue is accumulating to toxic levels that may create an exposure pathway, 3) identify climate scenarios for site locations and determine how short-and long-scale climate projections will influence spatial and temporal plant distribution for specific woody species; and 4) evaluate the risk perceptions of Hopi villages located five miles downstream of one site location. To date, risk perception and stakeholder outreach to the Hopi communities has been absent. This study will help inform how land use, water use, and sustenance practices may contribute to environmental health disparities for one of the few tribes that has maintained physical continuity within their ancestral homeland.

DEMONSTRATION BULLETIN: NEW YORK STATE MULTI-VENDOR BIOREMEDIATION - ENSR CONSULTING AND ENGINEERING/LARSEN ENGINEERS EX-SITU BIOVAULT

EPA Science Inventory

The ENSR Biovault Treatment Process is an ex-situ bioremediation technology for the treatment of organic contaminated soils. Contaminated soils placed in specially designed soil piles, referred to as biovaults, are remediated by stimulating the indigenous soil microbes to prolife...

BIOREMEDIATION IN THE FIELD SEARCH SYSTEM (BFSS) - VERSION 2.0 (DISKETTE)

EPA Science Inventory

BFSS is a PC-based software product that provides access to a database of information on waste sites in the United States and Canada where bioremediation is being tested or implemented, or has been completed. BFSS allows users to search the database electronically, view data on s...

MICROBIAL ANALYSIS OF MTBE, BTEX BIOREMEDIATION: BIONETS(TM) CONTAINING PM1, SOS, ISOLITE (R)

EPA Science Inventory

MTBE and BTEX (benzene, toluene, ethylbenzene, and xylene) are major problems of many sites in the United States. The objective of this study was to determine if biologically active in-situ BioNets could bioremediation MTBE and BTEX contaminated groundwater. Seven BioNets were ...

MICROBIAL ANALYSIS OF MTBE, BTEX BIOREMEDIATION: BIONETS CONTAINING PM1, SOS, ISOLITE.

EPA Science Inventory

MTBE and BTEX (benzene, toluene, ethylbenzene, and xylene) are major problems of many sites in the United States. The objective of this study was to determine if biologically active in-situ BioNets could bioremediation MTBE and BTEX contaminated groundwater. Seven BioNets were ...

Characterizing The Microbial Community In A TCE DNAPL Site: SABRE Column And Field Studies

EPA Science Inventory

The SABRE (Source Area BioREmediation) project is evaluating accelerated anaerobic bioremediation of chlorinated solvents in areas of high concentration, such as DNAPL source areas. In support of a field scale pilot test, column studies were conducted to design the system and ob...

APPLIED GEOLOGIC, MICROBIOLOGICAL, AND ENGINEERING CONSTRAINTS OF IN-SITU BTEX BIOREMEDIATION

EPA Science Inventory

An in-situ bioremediation project has been designed and constructed for a site in south-central Kansas just north of Wichita. A pipeline leaked an unknown quantity of refinedfuels in the 1970s. The spill was undetected until hydrocarbons were found in a nearby municipal water sup...

Complete Genome Sequence of Marinobacter flavimaris LMG 23834T, Which Is Potentially Useful in Bioremediation.

PubMed

Palau, Montserrat; Boujida, Nadia; Manresa, Àngels; Miñana-Galbis, David

2018-04-19

The complete genome sequence of the halophilic strain Marinobacter flavimaris LMG 23834 T is presented here. The genomic information of this type strain will be useful for taxonomic purposes and for its potential use in bioremediation studies. Copyright © 2018 Palau et al.

Bioremediation of treated wood with fungi

Treesearch

Barbara L. Illman; Vina W. Yang

2006-01-01

The authors have developed technologies for fungal bioremediation of waste wood treated with oilborne or metal-based preservatives. The technologies are based on specially formulated inoculum of wood-decay fungi, obtained through strain selection to obtain preservative-tolerant fungi. This waste management approach provides a product with reduced wood volume and the...

ASSESSMENT OF THE MICROBIAL POTENTIAL FOR NITRATE- ENHANCED BIOREMEDIATION OF A JP-4 FUEL-CONTAMINATED AQUIFER

EPA Science Inventory

A site that was contaminated with JP-4 jet fuel was characterized microbiologically to assess the feasibility of nitrate-enhanced bioremediation. The results of microcosm studies indicated that the mean pseudo zero-order rate constants for alkylbenzene biodegradation and NO3^...

LITERATURE REVIEW ON THE USE OF COMMERCIAL BIOREMEDIATION AGENTS FOR CLEAN-UP OF OIL-CONTAMINATED ESTUARINE ENVIRONMENTS

EPA Science Inventory

The objective of this document is to conduct a comprehensive review of the use of commercial bioremediation products treating oil spills in all environments, Literature assessed includes peer-reviewed articles, company reports, government reports, and reports by cleanup contracto...

BTEX AND MTBE BIOREMEDIATION: BIONETS™ CONTAINING SOS, PM1 AND ISOLITE®

EPA Science Inventory

MTBE and BTEX (benzene, toluene, ethylbenzene, and xylenes) are major problems of many sites in the United States. The objective of this study was to determine if biologically active in situ BioNets could bioremediate MTBE and BTEX contaminated groundwater. Seven BioNets w...

MICROBIAL ANALYSIS OF MTBE, BTEX BIOREMEDIATION: BIONETS CONTAINING PM1, SOS, ISOLITE�

EPA Science Inventory

MTBE and BTEX (benzene, toluene, ethylbenzene, and xylene) are major problems of many sites in the United States. The objective of this study was to determine if biologically active in-situ BioNets could bioremediate MTBE and BTEX contaminated groundwater. Seven BioNets were plac...

Comparative Demonstration of Active and Semi-Passive In Situ Bioremediation Approaches for Perchlorate Impacted Groundwater: Active In Situ Bioremediation Demonstration

DTIC Science & Technology

2013-04-01

demonstration test . 5.1 CONCEPTUAL EXPERIMENTAL DESIGN In concept, the active biobarrier approach involved the use of alternating extraction and injection...16 4.3 GROUNDWATER CHEMISTRY ....................................................................... 18 5.0 TEST DESIGN...20 5.1 CONCEPTUAL EXPERIMENTAL DESIGN

OIL SPILL BIOREMEDIATION ON COASTAL SHORELINES: A CRITIQUE

EPA Science Inventory

The purpose of this chapter is not to provide an extensive review of the literature on oil spill bioremediation. For that, the reader is referred to Swannell et al. (1996), who have conducted the most exhaustive review I have yet to come across. Other reviews are also av...

Compositions and methods of use of constructed microbial mats

DOEpatents

Bender, Judith A.; Phillips, Peter C.

2000-01-01

Compositions, methods and devices for bioremediation that comprise components of constructed microbial mats with organic and inorganic materials are described. The compositions, methods and devices can be used for bioremediation of different individual contaminants and for mixed or multiple contaminants, and for production of beneficial compositions and molecules.

DEVELOPMENT AND APPLICATION OF PROTOCOLS FOR EVALUATION OF OIL SPILL BIOREMEDIATION (RESEARCH BRIEF)

EPA Science Inventory

Protocols were developed and evaluated to assess the efficacy and environmental safety of commercial oil spill bioremediation agents (CBAs). Test systems that simulate oil slicks on open water or oiled sandy beaches were used to test the effectiveness of CBAs. Gravimetric and gas...

TOXICITY TRENDS DURING AN OIL SPILL BIOREMEDIATION EXPERIMENT ON A SANDY SHORELINE IN DELAWARE, USA

EPA Science Inventory

A 13-week, refereed, inter-agency toxicity testing program involving five bioassay methods was used to document the effectiveness of shoreline bioremediation to accelerate toxicity reduction of an oiled sandy shoreline at Fowler Beach, Delaware, USA. The study was part of an inte...

EARTH TECH INC.'S ENHANCED IN-SITU BIOREMEDIATION PROCESS; INNOVATIVE TECHNOLOGY EVALUATION REPORT

EPA Science Inventory

The USEPA conducted an evaluation of the Enhanced In-situ Bioremediation process, a biostimulation technology developed by the USDOE at the Westinghouse Savannah River Plant site in Aiken, SC. DOE has licensed the process to Earth Tech, Inc. The evaluation described in this bulle...

Next generation of microbial inoculants for agriculture and bioremediation.

PubMed

Baez-Rogelio, Antonino; Morales-García, Yolanda Elizabeth; Quintero-Hernández, Verónica; Muñoz-Rojas, Jesús

2017-01-01

In this Crystal Ball we describe the negative effects of the scheme of intensive agriculture of the green revolution technology. To recover the contaminated soils derived from intensive farming is necessary introduce new successful technologies to replace the use of chemical fertilizer and toxic pesticides by organic fertilizers and biological control agents. Our principal speculation is that in a short time authors in the field of PGPB and bioremediation will be expanding the knowledge on the development of different formulations containing super-bacteria or a mixture of super-bacteria able to provide beneficial effect for agriculture and bioremediation. © 2016 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Systems biology approach to bioremediation

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

Chakraborty, Romy; Wu, Cindy H.; Hazen, Terry C.

2012-06-01

Bioremediation has historically been approached as a ‘black box’ in terms of our fundamental understanding. Thus it succeeds and fails, seldom without a complete understanding of why. Systems biology is an integrated research approach to study complex biological systems, by investigating interactions and networks at the molecular, cellular, community, and ecosystem level. The knowledge of these interactions within individual components is fundamental to understanding the dynamics of the ecosystem under investigation. Finally, understanding and modeling functional microbial community structure and stress responses in environments at all levels have tremendous implications for our fundamental understanding of hydrobiogeochemical processes and the potentialmore » for making bioremediation breakthroughs and illuminating the ‘black box’.« less

Engineering Deinococcus geothermalis for Bioremediation of High-Temperature Radioactive Waste Environments

PubMed Central

Brim, Hassan; Venkateswaran, Amudhan; Kostandarithes, Heather M.; Fredrickson, James K.; Daly, Michael J.

2003-01-01

Deinococcus geothermalis is an extremely radiation-resistant thermophilic bacterium closely related to the mesophile Deinococcus radiodurans, which is being engineered for in situ bioremediation of radioactive wastes. We report that D. geothermalis is transformable with plasmids designed for D. radiodurans and have generated a Hg(II)-resistant D. geothermalis strain capable of reducing Hg(II) at elevated temperatures and in the presence of 50 Gy/h. Additionally, D. geothermalis is capable of reducing Fe(III)-nitrilotriacetic acid, U(VI), and Cr(VI). These characteristics support the prospective development of this thermophilic radiophile for bioremediation of radioactive mixed waste environments with temperatures as high as 55°C. PMID:12902245

Natural and accelerated bioremediation research program plan

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

NONE

1995-09-01

This draft plan describes a ten-year program to develop the scientific understanding needed to harness and develop natural and enhanced biogeochemical processes to bioremediate contaminated soils, sediments and groundwater at DOE facilities. The Office of Health and Environmental Research (OHER) developed this program plan, with advice and assistance from DOE`s Office of Environmental Management (EM). The program builds on OHER`s tradition of sponsoring fundamental research in the life and environmental sciences and was motivated by OHER`s and Office of Energy Research`s (OER`s) commitment to supporting DOE`s environmental management mission and the belief that bioremediation is an important part of themore » solution to DOE`s environmental problems.« less

In Situ Bioremediation of Energetic Compounds in Groundwater

DTIC Science & Technology

2012-05-01

42  Figure 16. Semi-passive bioremediation alternative with cheese whey for whole plume treatment...cheese whey for plume cutoff. ............. 46  Figure 18. Passive biobarrier alternative with EVO for plume cutoff... whey was utilized as a cosubstrate during the project based on extensive treatability testing. The overall performance of this design for remediation

ENHANCED IN SITU BIOREMEDIATION DEMONSTRATED IN FRACTURED BEDROCK IN: GROUND WATER CURRENTS NEWSLETTER, ISSUE 38, P. 2-3, 2000

EPA Science Inventory

The USEPA's SITE Program conducted a demonstration of the Enhanced In Situ Bioremediation Process at the ITT Industries Night Vision Facility in Roanoke, VA. The biostimulation process, developed by the USEOE and licensed to Earth Tech, Inc., involves injecting a mixture of air, ...

ANALYTICAL APPROXIMATION OF THE BIODEGRADATION RATE FOR IN SITU BIOREMEDIATION OF GROUNDWATER UNDER IDEAL RADIAL FLOW CONDITIONS. (R824785)

EPA Science Inventory

We derive the long-term biodegradation rate of an organic contaminant (substrate) for an in situ bioremediation model with axisymmetric flow conditions. The model presumes that a nonsorbing electron acceptor is injected into a saturated homogeneous porous medium which initially c...

J.R. SIMPLOT EX-SITU BIOREMEDIATION TECHNOLOGY FOR TREATMENT OF DINOSEB-CONTAMINATED SOILS - INNOVATIVE TECHNOLOGY REPORT

EPA Science Inventory

This report summarizes the findings of an evaluation of the J.R. Simplot Ex-Situ Bioremediation Technology on the degradation of dinoseb (2-set-butyl-4,6-dinitrophenol) an agricultural herbicide. This technology was developed by the J.R. Simplot Company (Simplot) to biologically ...

BIOSTIMULATION CAN SOMETIMES ENHANCE ENVIRONMENTAL CLEANUP - An Editorial Viewpoint on Bioremediation

EPA Science Inventory

The Exxon Valdex oil spill, which led to the enactment of the Oil Pollution Act of 1990, gave rise to the largest bioremediation field trial ever attempted. A research sutdy was conducted by EPA in 1989 and 1990 to develop data to support the recommendation to go forward w...

USE OF HOPANE AS A CONSERVATIVE BIOMARKER FOR MONITORING THE BIOREMEDIATION EFFECTIVENESS OF CRUDE OIL CONTAMINATING A SANDY BEACH

EPA Science Inventory

Much of the variability inherent in crude oil bioremediation field studies can be eliminated by normalizing analyte concentrations to the concentration of a nonbiodegradable biomarker such as hopane. This was demonstrated with data from a field study in which crude oil was intent...

Applications of DNA-Stable Isotope Probing in Bioremediation Studies

NASA Astrophysics Data System (ADS)

Chen, Yin; Vohra, Jyotsna; Murrell, J. Colin

DNA-stable isotope probing, a method to identify active microorganisms without the prerequisite of cultivation, has been widely applied in the study of microorganisms involved in the degradation of environmental pollutants. Recent advances and technique considerations in applying DNA-SIP in bioremediation are highlighted. A detailed protocol of a DNA-SIP experiment is provided.

Applications of DNA-stable isotope probing in bioremediation studies.

PubMed

Chen, Yin; Vohra, Jyotsna; Murrell, J Colin

2010-01-01

DNA-stable isotope probing, a method to identify active microorganisms without the prerequisite of cultivation, has been widely applied in the study of microorganisms involved in the degradation of environmental pollutants. Recent advances and technique considerations in applying DNA-SIP in bioremediation are highlighted. A detailed protocol of a DNA-SIP experiment is provided.

DEVELOPMENT OF BIOAVAILABILITY AND BIOKINETICS DETERMINATION METHODS FOR ORGANIC POLLUTANTS IN SOIL TO ENHANCE IN-SITU AND ON-SITE BIOREMEDIATION

EPA Science Inventory

Determination of biodegradation rates of organics in soil slurry and compacted soil systems is essential for evaluating the efficacy of bioremediation for treatment of contaminated soils. In this paper, a systematic protocol has been developed for evaluating bioknetic and transp...

PROTOCOL FOR DETERMINING BIOAVAILABILITY AND BIOKINETICS OF ORGANIC POLLUTANTS IN DISPERSED, COMPACTED AND INTACT SOIL SYSTEMS TO ENHANCE IN SITU BIOREMEDIATION

EPA Science Inventory

The development of effective in situ and on-site bioremediation technologies can facilitate the cleanup of chemically-contaminated soil sites. Knowledge of biodegradation kinetics and bioavailability of organic pollutants can facilitate decisions on the efficacy of in situ and o...

Bioremediation and degradation of CCA-treated wood waste.

Treesearch

Barbara L Illman; Vina W. Yang

2004-01-01

Bioprocessing CCA wood waste is an efficient and economical alternative to depositing the waste in landfills, especially if landfill restrictions on CCA waste are imposed nation wide. We have developed bioremediation and degradation technologies for microbial processing of CCA waste. The technologies are based on specially formulated inoculum of wood decay fungi,...

Bioremediation of Cd-DDT co-contaminated soil using the Cd-hyperaccumulator Sedum alfredii and DDT-degrading microbes

USDA-ARS?s Scientific Manuscript database

The development of an integrated strategy for the remediation of soil co-contaminated by heavy metals and persistent organic pollutants is a major research priority for the decontamination of soil slated for use in agricultural production. The objective of this study was to develop a bioremediation ...

IN SITU BIOREMEDIATION OF TRICHLOROETHYLENE USING BURKHOLDERIA CEPACIA G4 PR1: ANALYSIS OF MICROBIAL ECOLOGY PARAMETERS FOR RISK ASSESSMENT (RESEARCH BRIEF)

EPA Science Inventory

The introduction of bacteria into aquifers for bioremediation purposes requires monitoring of the persistence and activity of microbial populations for efficacy and risk assessment purposes. Burkholderia cepacia G4 PR1 constitutively expresses a toluene ortho-monooxygenase (tom) ...

Bioremediation of high molecular weight polyaromatic hydrocarbons co-contaminated with metals in liquid and soil slurries by metal tolerant PAHs degrading bacterial consortium.

PubMed

Thavamani, Palanisami; Megharaj, Mallavarapu; Naidu, Ravi

2012-11-01

Bioremediation of polyaromatic hydrocarbons (PAH) contaminated soils in the presence of heavy metals have proved to be difficult and often challenging due to the ability of toxic metals to inhibit PAH degradation by bacteria. In this study, a mixed bacterial culture designated as consortium-5 was isolated from a former manufactured gas plant (MGP) site. The ability of this consortium to utilise HMW PAHs such as pyrene and BaP as a sole carbon source in the presence of toxic metal Cd was demonstrated. Furthermore, this consortium has proven to be effective in degradation of HMW PAHs even from the real long term contaminated MGP soil. Thus, the results of this study demonstrate the great potential of this consortium for field scale bioremediation of PAHs in long term mix contaminated soils such as MGP sites. To our knowledge this is the first study to isolate and characterize metal tolerant HMW PAH degrading bacterial consortium which shows great potential in bioremediation of mixed contaminated soils such as MGP.

Bioremediation and fodder potentials of two Sargassum spp. in coastal waters of Shenzhen, South China.

PubMed

Yu, Zonghe; Zhu, Xiaoshan; Jiang, Yuelu; Luo, Peng; Hu, Chaoqun

2014-08-30

In this study, the bioremediation potentials of two seaweeds (Sargassum hemiphyllum and S. henslowianum) against pollution in a coastal mariculture area of Shenzhen, South China, were investigated by comparing the growth, nutrient bioaccumulation capacity of plants from the seaweed bed (control site) with plants from the fish farm. Results indicated that both species are potential candidates for bioremediation in the fish farm areas in terms of their high growth rates and high bioaccumulation capacities on inorganic nutrients. Both Sargassum spp. contain high levels of crude protein (11.7-14.0%) and crude fat (2.2-2.7%), suggesting high nutritional values. The S. hemiphyllum may serve as a good aquaculture fodder with high nutritional compositions and low heavy metal contents. However, heavy metals (Cr, Pb and Cd) of S. henslowianum exceed the maximum allowable concentrations as aquatic feed, which restricts its fodder application. In general, the results of this study may contribute to the marine pollution bioremediation in the coastal areas of South China, especially in mariculture zones. Copyright © 2013 Elsevier Ltd. All rights reserved.

Horizontal gene transfer versus biostimulation: A strategy for bioremediation in Goa.

PubMed

Pasumarthi, Rajesh; Mutnuri, Srikanth

2016-12-15

Bioaugmentation, Biostimulation and Horizontal gene transfer (HGT) of catabolic genes have been proven for their role in bioremediation of hydrocarbons. It also has been proved that selection of either biostimulation or bioremediation varies for every contaminated site. The reliability of HGT compared to biostimulation and bioremediation was not tested. The present study focuses on reliability of biostimulatiion, bioaugmentation and HGT during biodegradation of Diesel oil and Non aqueous phase liquids (NAPL). Pseudomonas aeruginosa (AEBBITS1) having alkB and NDO genes was used for bioaugmentation and the experiment was conducted using seawater as medium. Based on Gas chromatography results diesel was found to be degraded to 100% in both presence and absence of AEBBITS1. Denturing gradient gel electrophoresis result showed same pattern in presence and absence of AEBBITS1 indicating no HGT. NAPL degradation was found to be more by Biostimulated Bioaugmentation compared to biostimulation and bioaugmentation alone. This proves that biostimulated bioaugmentation is better strategy for oil contamination (tarabll) in Velsao beach, Goa. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Biological treatments for contaminated soils: hydrocarbon contamination. Fungal applications in bioremediation treatment].

PubMed

Martín Moreno, Carmen; González Becerra, Aldo; Blanco Santos, María José

2004-09-01

Bioremediation is a spontaneous or controlled process in which biological, mainly microbiological, methods are used to degrade or transform contaminants to non or less toxic products, reducing the environmental pollution. The most important parameters to define a contaminated site are: biodegradability, contaminant distribution, lixiviation grade, chemical reactivity of the contaminants, soil type and properties, oxygen availability and occurrence of inhibitory substances. Biological treatments of organic contaminations are based on the degradative abilities of the microorganisms. Therefore the knowledge on the physiology and ecology of the biological species or consortia involved as well as the characteristics of the polluted sites are decisive factors to select an adequate biorremediation protocol. Basidiomycetes which cause white rot decay of wood are able to degrade lignin and a variety of environmentally persistent pollutants. Thus, white rot fungi and their enzymes are thought to be useful not only in some industrial process like biopulping and biobleaching but also in bioremediation. This paper provides a review of different aspects of bioremediation technologies and recent advances on ligninolytic metabolism research.

A case study of the intrinsic bioremediation of petroleum hydrocarbons

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

Barker, G.W.; Raterman, K.T.; Fisher, J.B.

1995-12-31

Condensate liquids have been found to contaminate soil and groundwater at two gas production sites in the Denver Basin operated by Amoco Production Co. These sites have been closely monitored since July 1993 to determine whether intrinsic aerobic or anaerobic bioremediation of hydrocarbons occurs at a sufficient rate and to an adequate endpoint to support a no-intervention decision. Groundwater monitoring and analysis of soil cores suggest that intrinsic bioremediation is occurring at these sites by multiple pathways including aerobic oxidation, Fe{sup 3+} reduction, and sulfate reduction. In laboratory experiments the addition of gas condensate hydrocarbons to saturated soil from themore » gas production site stimulated sulfate reduction under anaerobic and oxygen-limiting conditions, and nitrate and Fe{sup 3+} reduction under oxygen-limiting conditions, compared to biotic controls that lacked hydrocarbon and sterile controls. The sulfate reduction corresponded to a reduction in the amount of toluene relative to other hydrocarbons. These results confirmed that subsurface soils at the gas production site have the potential for intrinsic bioremediation of hydrocarbons.« less

Biodegradation of Hopane Prevents Use As Conservative Biomarker During Bioremediation of PAHs in Petroleum Contaminated Soils

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

Huesemann, Michael H.; Hausmann, Tom S.; Fortman, Timothy J.

The pentacyclic triterpane C30 17a (H), 21b (H)-hopane, a biomarker commonly used in hydrocarbon bioremediation laboratory experiments and field studies, was found to be completely removed without the formation of the demethylated intermediate nor-hopane in a crude oil contaminated soil undergoing slurry biotreatment while PAHs such as benzo(e)pyrene were recalcitrant. The partial or complete biodegradation of hopane has also been previously reported in a few bioremediation studies and has been explored by petroleum geochemists in an effort to characterize crude oil deposits. It is currently not clear what conditions induce hopane biodegradation or biotransformation, although the use of microbial enrichmentmore » cultures appears to speed up the process. Considering that hopane is not necessarily conserved during a bioremediation study, the uncritical normalization of hydrocarbon concentrations using this biomarker can lead to incorrect estimates of biodegradation rates and extents. If hopane is found to be unstable in a particular case, other potential biomarkers such as pentahopane, oleanane, or vanadium may be used instead.« less

Overview of on-farm bioremediation systems to reduce the occurrence of point source contamination.

PubMed

De Wilde, Tineke; Spanoghe, Pieter; Debaer, Christof; Ryckeboer, Jaak; Springael, Dirk; Jaeken, Peter

2007-02-01

Contamination of ground and surface water puts pressure on the use of pesticides. Pesticide contamination of water can often be linked to point sources rather than to diffuse sources. Examples of such point sources are areas on farms where pesticides are handled and filled into sprayers, and where sprayers are cleaned. To reduce contamination from these point sources, different kinds of bioremediation system are being researched in various member states of the EU. Bioremediation is the use of living organisms, primarily microorganisms, to degrade the environmental contaminants into less toxic forms. The systems available for biocleaning of pesticides vary according to their shape and design. Up till now, three systems have been extensively described and reported: the biobed, the Phytobac and the biofilter. Most of these constructions are excavations or different sizes of container filled with biological material. Typical overall clean-up efficiency exceeds 95%, realising even more than 99% in many cases. This paper provides an overview of the state of the art of these bioremediation systems and discusses their construction, efficiency and drawbacks.

Electron transport chains in organohalide-respiring bacteria and bioremediation implications.

PubMed

Wang, Shanquan; Qiu, Lan; Liu, Xiaowei; Xu, Guofang; Siegert, Michael; Lu, Qihong; Juneau, Philippe; Yu, Ling; Liang, Dawei; He, Zhili; Qiu, Rongliang

In situ remediation employing organohalide-respiring bacteria represents a promising solution for cleanup of persistent organohalide pollutants. The organohalide-respiring bacteria conserve energy by utilizing H 2 or organic compounds as electron donors and organohalides as electron acceptors. Reductive dehalogenase (RDase), a terminal reductase of the electron transport chain in organohalide-respiring bacteria, is the key enzyme that catalyzes halogen removal. Accumulating experimental evidence thus far suggests that there are distinct models for respiratory electron transfer in organohalide-respirers of different lineages, e.g., Dehalococcoides, Dehalobacter, Desulfitobacterium and Sulfurospirillum. In this review, to connect the knowledge in organohalide-respiratory electron transport chains to bioremediation applications, we first comprehensively review molecular components and their organization, together with energetics of the organohalide-respiratory electron transport chains, as well as recent elucidation of intramolecular electron shuttling and halogen elimination mechanisms of RDases. We then highlight the implications of organohalide-respiratory electron transport chains in stimulated bioremediation. In addition, major challenges and further developments toward understanding the organohalide-respiratory electron transport chains and their bioremediation applications are identified and discussed. Copyright © 2018 Elsevier Inc. All rights reserved.

Assessment of the horizontal transfer of functional genes as a suitable approach for evaluation of the bioremediation potential of petroleum-contaminated sites: a mini-review.

PubMed

Shahi, Aiyoub; Ince, Bahar; Aydin, Sevcan; Ince, Orhan

2017-06-01

Petroleum sludge contains recalcitrant residuals. These compounds because of being toxic to humans and other organism are of the major concerns. Therefore, petroleum sludge should be safely disposed. Physicochemical methods which are used by this sector are mostly expensive and need complex devices. Bioremediation methods because of being eco-friendly and cost-effective overcome most of the limitations of physicochemical treatments. Microbial strains capable to degrade petroleum hydrocarbons are practically present in all soils and sediments and their population density increases in contact with contaminants. Bacterial strains cannot degrade alone all kinds of petroleum hydrocarbons, rather microbial consortium should collaborate with each other for degradation of petroleum hydrocarbon mixtures. Horizontal transfer of functional genes between bacteria plays an important role in increasing the metabolic potential of the microbial community. Therefore, selecting a suitable degrading gene and tracking its horizontal transfer would be a useful approach to evaluate the bioremediation process and to assess the bioremediation potential of contaminated sites.

Reflection on Molecular Approaches Influencing State-of-the-Art Bioremediation Design: Culturing to Microbial Community Fingerprinting to Omics

PubMed Central

Czaplicki, Lauren M.; Gunsch, Claudia K.

2017-01-01

Bioremediation is generally viewed as a cost effective and sustainable technology because it relies on microbes to transform pollutants into benign compounds. Advances in molecular biological analyses allow unprecedented microbial detection and are increasingly incorporated into bioremediation. Throughout history, state-of-the-art techniques have informed bioremediation strategies. However, the insights those techniques provided were not as in depth as those provided by recently developed omics tools. Advances in next generation sequencing (NGS) have now placed metagenomics and metatranscriptomics within reach of environmental engineers. As NGS costs decrease, metagenomics and metatranscriptomics have become increasingly feasible options to rapidly scan sites for specific degradative functions and identify microorganisms important in pollutant degradation. These omic techniques are capable of revolutionizing biological treatment in environmental engineering by allowing highly sensitive characterization of previously uncultured microorganisms. Omics enables the discovery of novel microorganisms for use in bioaugmentation and supports systematic optimization of biostimulation strategies. This review describes the omics journey from roots in biology and medicine to its current status in environmental engineering including potential future directions in commercial application. PMID:28348455

Bioremediation: a genuine technology to remediate radionuclides from the environment

PubMed Central

Prakash, Dhan; Gabani, Prashant; Chandel, Anuj K; Ronen, Zeev; Singh, Om V

2013-01-01

Summary Radionuclides in the environment are a major human and environmental health concern. Like the Chernobyl disaster of 1986, the Fukushima Daiichi nuclear disaster in 2011 is once again causing damage to the environment: a large quantity of radioactive waste is being generated and dumped into the environment, and if the general population is exposed to it, may cause serious life-threatening disorders. Bioremediation has been viewed as the ecologically responsible alternative to environmentally destructive physical remediation. Microorganisms carry endogenous genetic, biochemical and physiological properties that make them ideal agents for pollutant remediation in soil and groundwater. Attempts have been made to develop native or genetically engineered (GE) microbes for the remediation of environmental contaminants including radionuclides. Microorganism-mediated bioremediation can affect the solubility, bioavailability and mobility of radionuclides. Therefore, we aim to unveil the microbial-mediated mechanisms for biotransformation of radionuclides under various environmental conditions as developing strategies for waste management of radionuclides. A discussion follows of ‘-omics’-integrated genomics and proteomics technologies, which can be used to trace the genes and proteins of interest in a given microorganism towards a cell-free bioremediation strategy. PMID:23617701

Versatility of Streptomyces sp. M7 to bioremediate soils co-contaminated with Cr(VI) and lindane.

PubMed

Aparicio, JuanDaniel; Solá, María Zoleica Simón; Benimeli, Claudia Susana; Amoroso, María Julia; Polti, Marta Alejandra

2015-06-01

The aim of this work was to study the impact of environmental factors on the bioremediation of Cr(VI) and lindane contaminated soil, by an actinobacterium, Streptomyces sp. M7, in order to optimize the process. Soil samples were contaminated with 25 µg kg(-1) of lindane and 50 mg kg(-1) of Cr(VI) and inoculated with Streptomyces sp. M7. The lowest inoculum concentration which simultaneously produced highest removal of Cr(VI) and lindane was 1 g kg(-1). The influence of physical and chemical parameters was assessed using a full factorial design. The factors and levels tested were: Temperature: 25, 30, 35°C; Humidity: 10%, 20%, 30%; Initial Cr(VI) concentration: 20, 50, 80 mg kg(-1); Initial lindane concentration: 10, 25, 40 µg kg(-1). Streptomyces sp. M7 exhibited strong versatility, showing the ability to bioremediate co-contaminated soil samples at several physicochemical conditions. Streptomyces sp. M7 inoculum size was optimized. Also, it was fitted a model to study this process, and it was possible to predict the system performance, knowing the initial conditions. Moreover, optimum temperature and humidity conditions for the bioremediation of soil with different concentrations of Cr(VI) and lindane were determined. Lettuce seedlings were a suitable biomarker to evaluate the contaminants mixture toxicity. Streptomyces sp. M7 carried out a successful bioremediation, which was demonstrated through ecotoxicity test with Lactuca sativa. Copyright © 2015 Elsevier Inc. All rights reserved.

Effect of alternating bioremediation and electrokinetics on the remediation of n-hexadecane-contaminated soil

PubMed Central

Wang, Sa; Guo, Shuhai; Li, Fengmei; Yang, Xuelian; Teng, Fei; Wang, Jianing

2016-01-01

This study demonstrated the highly efficient degradation of n-hexadecane in soil, realized by alternating bioremediation and electrokinetic technologies. Using an alternating technology instead of simultaneous application prevented competition between the processes that would lower their efficiency. For the consumption of the soil dissolved organic matter (DOM) necessary for bioremediation by electrokinetics, bioremediation was performed first. Because of the utilization and loss of the DOM and water-soluble ions by the microbial and electrokinetic processes, respectively, both of them were supplemented to provide a basic carbon resource, maintain a high electrical conductivity and produce a uniform distribution of ions. The moisture and bacteria were also supplemented. The optimal DOM supplement (20.5 mg·kg−1 glucose; 80–90% of the total natural DOM content in the soil) was calculated to avoid competitive effects (between the DOM and n-hexadecane) and to prevent nutritional deficiency. The replenishment of the water-soluble ions maintained their content equal to their initial concentrations. The degradation rate of n-hexadecane was only 167.0 mg·kg−1·d−1 (1.9%, w/w) for the first 9 days in the treatments with bioremediation or electrokinetics alone, but this rate was realized throughout the whole process when the two technologies were alternated, with a degradation of 78.5% ± 2.0% for the n-hexadecane after 45 days of treatment. PMID:27032838

Bioremediation in fractured rock: 1. Modeling to inform design, monitoring, and expectations

USGS Publications Warehouse

Tiedeman, Claire; Shapiro, Allen M.; Hsieh, Paul A.; Imbrigiotta, Thomas; Goode, Daniel J.; Lacombe, Pierre; DeFlaun, Mary F.; Drew, Scott R.; Johnson, Carole D.; Williams, John H.; Curtis, Gary P.

2018-01-01

Field characterization of a trichloroethene (TCE) source area in fractured mudstones produced a detailed understanding of the geology, contaminant distribution in fractures and the rock matrix, and hydraulic and transport properties. Groundwater flow and chemical transport modeling that synthesized the field characterization information proved critical for designing bioremediation of the source area. The planned bioremediation involved injecting emulsified vegetable oil and bacteria to enhance the naturally occurring biodegradation of TCE. The flow and transport modeling showed that injection will spread amendments widely over a zone of lower‐permeability fractures, with long residence times expected because of small velocities after injection and sorption of emulsified vegetable oil onto solids. Amendments transported out of this zone will be diluted by groundwater flux from other areas, limiting bioremediation effectiveness downgradient. At nearby pumping wells, further dilution is expected to make bioremediation effects undetectable in the pumped water. The results emphasize that in fracture‐dominated flow regimes, the extent of injected amendments cannot be conceptualized using simple homogeneous models of groundwater flow commonly adopted to design injections in unconsolidated porous media (e.g., radial diverging or dipole flow regimes). Instead, it is important to synthesize site characterization information using a groundwater flow model that includes discrete features representing high‐ and low‐permeability fractures. This type of model accounts for the highly heterogeneous hydraulic conductivity and groundwater fluxes in fractured‐rock aquifers, and facilitates designing injection strategies that target specific volumes of the aquifer and maximize the distribution of amendments over these volumes.

Management of groundwater in-situ bioremediation system using reactive transport modelling under parametric uncertainty: field scale application

NASA Astrophysics Data System (ADS)

Verardo, E.; Atteia, O.; Rouvreau, L.

2015-12-01

In-situ bioremediation is a commonly used remediation technology to clean up the subsurface of petroleum-contaminated sites. Forecasting remedial performance (in terms of flux and mass reduction) is a challenge due to uncertainties associated with source properties and the uncertainties associated with contribution and efficiency of concentration reducing mechanisms. In this study, predictive uncertainty analysis of bio-remediation system efficiency is carried out with the null-space Monte Carlo (NSMC) method which combines the calibration solution-space parameters with the ensemble of null-space parameters, creating sets of calibration-constrained parameters for input to follow-on remedial efficiency. The first step in the NSMC methodology for uncertainty analysis is model calibration. The model calibration was conducted by matching simulated BTEX concentration to a total of 48 observations from historical data before implementation of treatment. Two different bio-remediation designs were then implemented in the calibrated model. The first consists in pumping/injection wells and the second in permeable barrier coupled with infiltration across slotted piping. The NSMC method was used to calculate 1000 calibration-constrained parameter sets for the two different models. Several variants of the method were implemented to investigate their effect on the efficiency of the NSMC method. The first variant implementation of the NSMC is based on a single calibrated model. In the second variant, models were calibrated from different initial parameter sets. NSMC calibration-constrained parameter sets were sampled from these different calibrated models. We demonstrate that in context of nonlinear model, second variant avoids to underestimate parameter uncertainty which may lead to a poor quantification of predictive uncertainty. Application of the proposed approach to manage bioremediation of groundwater in a real site shows that it is effective to provide support in management of the in-situ bioremediation systems. Moreover, this study demonstrates that the NSMC method provides a computationally efficient and practical methodology of utilizing model predictive uncertainty methods in environmental management.

Plant Enhanced Bioremediation of Dissolved Toluene in Large Scale Column Setup

NASA Astrophysics Data System (ADS)

Basu, S.; Yadav, B. K.; Mathur, S.

2016-12-01

Hydrocarbons like BTEX compounds entering the soil-water system through anthropogenic activities can be long lasting sources of pollution, and thus, it is essential to look for remediation options that are environmentally benign. Bioremediation is a promising cost effective technique causing no harm to the contaminated ecosystem as compared to the traditional physicochemical methods. Natural microbes degrade contaminants from polluted soil water resources in bioremediation; however this process of natural bioremediation is quite slow under prevailing environmental conditions of a typical polluted site. Research has also proven that plants play an important role when it comes to accelerate the degradation rate cost-effectively in enhanced bioremediation technique. Thus in this study, fate and transport of dissolved toluene from a source zone to down-gradient receptors in a continuous soil-water plant system was investigated. For this, two sets of large scale column experiments were performed by connecting them with a treatment wetland having canna plants in first set and unplanted gravel bed in the second set. A continuous source of toluene contaminated water was supplied at the top of the column setups. A constant groundwater flow velocity of 0.625 cm/hr was maintained in the vertical direction. Free drainage was allowed at the bottom and a constant hydraulic head of 2.0 cm was maintained at the top boundary throughout the period of the experiments in both the cases. The observed microbial colonies using the plate counting method along with measured dissolved oxygen (DO) proved that the BTEX compound degraded aerobically at a faster rate in the first set. Plants played a positive role in enhancing biodegradation rate of the BTEX compound during its transport through the porous media. Finally the observed data of the column experiments were compared with the breakthrough curves obtained numerically solving the advection dispersion equation. The results of this research can be used to obtain vital information on framing the engineered bioremediation planning for contaminated sites.

In situ groundwater and sediment bioremediation: barriers and perspectives at European contaminated sites.

PubMed

Majone, Mauro; Verdini, Roberta; Aulenta, Federico; Rossetti, Simona; Tandoi, Valter; Kalogerakis, Nicolas; Agathos, Spiros; Puig, Sebastià; Zanaroli, Giulio; Fava, Fabio

2015-01-25

This paper contains a critical examination of the current application of environmental biotechnologies in the field of bioremediation of contaminated groundwater and sediments. Based on analysis of conventional technologies applied in several European Countries and in the US, scientific, technical and administrative barriers and constraints which still need to be overcome for an improved exploitation of bioremediation are discussed. From this general survey, it is evident that in situ bioremediation is a highly promising and cost-effective technology for remediation of contaminated soil, groundwater and sediments. The wide metabolic diversity of microorganisms makes it applicable to an ever-increasing number of contaminants and contamination scenarios. On the other hand, in situ bioremediation is highly knowledge-intensive and its application requires a thorough understanding of the geochemistry, hydrogeology, microbiology and ecology of contaminated soils, groundwater and sediments, under both natural and engineered conditions. Hence, its potential still remains partially unexploited, largely because of a lack of general consensus and public concerns regarding the lack of effectiveness and control, poor reliability, and possible occurrence of side effects, for example accumulation of toxic metabolites and pathogens. Basic, applied and pre-normative research are all needed to overcome these barriers and make in situ bioremediation more reliable, robust and acceptable to the public, as well as economically more competitive. Research efforts should not be restricted to a deeper understanding of relevant microbial reactions, but also include their interactions with the large array of other relevant phenomena, as a function of the truly variable site-specific conditions. There is a need for a further development and application of advanced biomolecular tools for site investigation, as well as of advanced metabolic and kinetic modelling tools. These would allow a quicker evaluation of the bioremediation potential of a site, and in turn a preliminary assessment of the technical feasibility of the chosen bioprocess which could replace or at least reduce the need for time-consuming and expensive field tests. At the same time, field tests will probably remain unavoidable for a detailed design of full scale remedial actions and the above reported tools will in any event be useful for a better design and a more reliable operation. Copyright © 2014 Elsevier B.V. All rights reserved.

A review on slurry bioreactors for bioremediation of soils and sediments

PubMed Central

Robles-González, Ireri V; Fava, Fabio; Poggi-Varaldo, Héctor M

2008-01-01

The aim of this work is to present a critical review on slurry bioreactors (SB) and their application to bioremediation of soils and sediments polluted with recalcitrant and toxic compounds. The scope of the review encompasses the following subjects: (i) process fundamentals of SB and analysis of advantages and disadvantages; (ii) the most recent applications of SB to laboratory scale and commercial scale soil bioremediation, with a focus on pesticides, explosives, polynuclear aromatic hydrocarbons, and chlorinated organic pollutants; (iii) trends on the use of surfactants to improve availability of contaminants and supplementation with degradable carbon sources to enhance cometabolism of pollutants; (iv) recent findings on the utilization of electron acceptors other than oxygen; (v) bioaugmentation and advances made on characterization of microbial communities of SB; (vi) developments on ecotoxicity assays aimed at evaluating bioremediation efficiency of the process. From this review it can be concluded that SB is an effective ad situ and ex situ technology that can be used for bioremediation of problematic sites, such as those characterized by soils with high contents of clay and organic matter, by pollutants that are recalcitrant, toxic, and display hysteretic behavior, or when bioremediation should be accomplished in short times under the pressure and monitoring of environmental agencies and regulators. SB technology allows for the convenient manipulation and control of several environmental parameters that could lead to enhanced and faster treatment of polluted soils: nutrient N, P and organic carbon source (biostimulation), inocula (bioaugmentation), increased availability of pollutants by use of surfactants or inducing biosurfactant production inside the SB, etc. An interesting emerging area is the use of SB with simultaneous electron acceptors, which has demonstrated its usefulness for the bioremediation of soils polluted with hydrocarbons and some organochlorinated compounds. Characterization studies of microbial communities of SB are still in the early stages, in spite of their significance for improving reactor operation and design optimization. We have identified the following niches of research needs for SB in the near and mid term future, inter alia: (i) application of SB with sequential and simultaneous electron acceptors to soils polluted with contaminants other than hydrocarbons (i.e., pesticides, explosives, etc.), (ii) evaluation of the technical feasibility of triphasic SB that use innocuous solvents to help desorbing pollutants strongly attached to soils, and in turn, to enhance their biodegradation, (iii) gaining deeper insight of microbial communities present in SB with the intensified application of molecular biology tools such as PCR-DGGE, PCR-TGGE, ARDRA, etc., (iv) development of more representative ecotoxicological assays to better assess the effectiveness of a given bioremediation process. PMID:18312630

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

Lombardo, N.J.; Marseille, T.J.; White, M.D.

TRUMP-BD (Boil Down) is an extension of the TRUMP (Edwards 1972) computer program for the analysis of nuclear fuel assemblies under severe accident conditions. This extension allows prediction of the heat transfer rates, metal-water oxidation rates, fission product release rates, steam generation and consumption rates, and temperature distributions for nuclear fuel assemblies under core uncovery conditions. The heat transfer processes include conduction in solid structures, convection across fluid-solid boundaries, and radiation between interacting surfaces. Metal-water reaction kinetics are modeled with empirical relationships to predict the oxidation rates of steam-exposed Zircaloy and uranium metal. The metal-water oxidation models are parabolic inmore » form with an Arrhenius temperature dependence. Uranium oxidation begins when fuel cladding failure occurs; Zircaloy oxidation occurs continuously at temperatures above 13000{degree}F when metal and steam are available. From the metal-water reactions, the hydrogen generation rate, total hydrogen release, and temporal and spatial distribution of oxide formations are computed. Consumption of steam from the oxidation reactions and the effect of hydrogen on the coolant properties is modeled for independent coolant flow channels. Fission product release from exposed uranium metal Zircaloy-clad fuel is modeled using empirical time and temperature relationships that consider the release to be subject to oxidation and volitization/diffusion ( bake-out'') release mechanisms. Release of the volatile species of iodine (I), tellurium (Te), cesium (Ce), ruthenium (Ru), strontium (Sr), zirconium (Zr), cerium (Cr), and barium (Ba) from uranium metal fuel may be modeled.« less

Mechanism of Uranium Reduction and Immobilization in Desulfovibrio vulgaris Biofilms.

PubMed

Stylo, Malgorzata; Neubert, Nadja; Roebbert, Yvonne; Weyer, Stefan; Bernier-Latmani, Rizlan

2015-09-01

The prevalent formation of noncrystalline U(IV) species in the subsurface and their enhanced susceptibility to reoxidation and remobilization, as compared to crystalline uraninite, raise concerns about the long-term sustainability of the bioremediation of U-contaminated sites. The main goal of this study was to resolve the remaining uncertainty concerning the formation mechanism of noncrystalline U(IV) in the environment. Controlled laboratory biofilm systems (biotic, abiotic, and mixed biotic-abiotic) were probed using a combination of U isotope fractionation and X-ray absorption spectroscopy (XAS). Regardless of the mechanism of U reduction, the presence of a biofilm resulted in the formation of noncrystalline U(IV). Our results also show that biotic U reduction is the most effective way to immobilize and reduce U. However, the mixed biotic-abiotic system resembled more closely an abiotic system: (i) the U(IV) solid phase lacked a typically biotic isotope signature and (ii) elemental sulfur was detected, which indicates the oxidation of sulfide coupled to U(VI) reduction. The predominance of abiotic U reduction in our systems is due to the lack of available aqueous U(VI) species for direct enzymatic reduction. In contrast, in cases where bicarbonate is present at a higher concentration, aqueous U(VI) species dominate, allowing biotic U reduction to outcompete the abiotic processes.

Functional gene array-based analysis of microbial community structure in groundwaters with a gradient of contaminant levels

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

Waldron, P.J.; Wu, L.; Van Nostrand, J.D.

2009-06-15

To understand how contaminants affect microbial community diversity, heterogeneity, and functional structure, six groundwater monitoring wells from the Field Research Center of the U.S. Department of Energy Environmental Remediation Science Program (ERSP; Oak Ridge, TN), with a wide range of pH, nitrate, and heavy metal contamination were investigated. DNA from the groundwater community was analyzed with a functional gene array containing 2006 probes to detect genes involved in metal resistance, sulfate reduction, organic contaminant degradation, and carbon and nitrogen cycling. Microbial diversity decreased in relation to the contamination levels of the wells. Highly contaminated wells had lower gene diversity butmore » greater signal intensity than the pristine well. The microbial composition was heterogeneous, with 17-70% overlap between different wells. Metal-resistant and metal-reducing microorganisms were detected in both contaminated and pristine wells, suggesting the potential for successful bioremediation of metal-contaminated groundwaters. In addition, results of Mantel tests and canonical correspondence analysis indicate that nitrate, sulfate, pH, uranium, and technetium have a significant (p < 0.05) effect on microbial community structure. This study provides an overall picture of microbial community structure in contaminated environments with functional gene arrays by showing that diversity and heterogeneity can vary greatly in relation to contamination.« less

Microbially Mediated Kinetic Sulfur Isotope Fractionation: Reactive Transport Modeling Benchmark

NASA Astrophysics Data System (ADS)

Wanner, C.; Druhan, J. L.; Cheng, Y.; Amos, R. T.; Steefel, C. I.; Ajo Franklin, J. B.

2014-12-01

Microbially mediated sulfate reduction is a ubiquitous process in many subsurface systems. Isotopic fractionation is characteristic of this anaerobic process, since sulfate reducing bacteria (SRB) favor the reduction of the lighter sulfate isotopologue (S32O42-) over the heavier isotopologue (S34O42-). Detection of isotopic shifts have been utilized as a proxy for the onset of sulfate reduction in subsurface systems such as oil reservoirs and aquifers undergoing uranium bioremediation. Reactive transport modeling (RTM) of kinetic sulfur isotope fractionation has been applied to field and laboratory studies. These RTM approaches employ different mathematical formulations in the representation of kinetic sulfur isotope fractionation. In order to test the various formulations, we propose a benchmark problem set for the simulation of kinetic sulfur isotope fractionation during microbially mediated sulfate reduction. The benchmark problem set is comprised of four problem levels and is based on a recent laboratory column experimental study of sulfur isotope fractionation. Pertinent processes impacting sulfur isotopic composition such as microbial sulfate reduction and dispersion are included in the problem set. To date, participating RTM codes are: CRUNCHTOPE, TOUGHREACT, MIN3P and THE GEOCHEMIST'S WORKBENCH. Preliminary results from various codes show reasonable agreement for the problem levels simulating sulfur isotope fractionation in 1D.

COMBINED LABORATORY/FIELD STUDY ON THE USE OF NITRATE FOR IN SITU BIOREMEDIATION OF A FUEL-CONTAMINATED AQUIFER

EPA Science Inventory

A pilot demonstration project was conducted at Eglin Air Force Base, FL, to compare the extent of bioremediation of a fuel-contaminated aquifer using sprinkler application with and without nitrate addition on two adjacent 30 m x 30 m cells. Target compound groups included both B...

Bioremediation of nanomaterials

DOEpatents

Chen, Frank Fanqing; Keasling, Jay D; Tang, Yinjie J

2013-05-14

The present invention provides a method comprising the use of microorganisms for nanotoxicity study and bioremediation. In some embodiment, the microorganisms are bacterial organisms such as Gram negative bacteria, which are used as model organisms to study the nanotoxicity of the fullerene compounds: E. coli W3110, a human related enterobacterium and Shewanella oneidensis MR-1, an environmentally important bacterium with versatile metabolism.

Monitored Natural Attenuation of Perchlorate in Groundwater

DTIC Science & Technology

2010-09-01

has been used for industrial purposes, such as fireworks manufacturing, munitions production, pesticide production, and research and manufacturing of...Field Services Division, Washington, DC, August 2006. Hunter, W.J. 2002. Bioremediation of Chlorate or Perchlorate Contaminated Water Using ...5.2.2.1 A-82 Pump-and-Treat System ................................................ 20 5.2.2.2 In Situ Bioremediation Pilot Test

Mathematical Modelling of Bacterial Populations in Bio-remediation Processes

NASA Astrophysics Data System (ADS)

Vasiliadou, Ioanna A.; Vayenas, Dimitris V.; Chrysikopoulos, Constantinos V.

2011-09-01

An understanding of bacterial behaviour concerns many field applications, such as the enhancement of water, wastewater and subsurface bio-remediation, the prevention of environmental pollution and the protection of human health. Numerous microorganisms have been identified to be able to degrade chemical pollutants, thus, a variety of bacteria are known that can be used in bio-remediation processes. In this study the development of mathematical models capable of describing bacterial behaviour considered in bio-augmentation plans, such as bacterial growth, consumption of nutrients, removal of pollutants, bacterial transport and attachment in porous media, is presented. The mathematical models may be used as a guide in designing and assessing the conditions under which areas contaminated with pollutants can be better remediated.

Bioremediation of mercury: not properly exploited in contaminated soils!

PubMed

Mahbub, Khandaker Rayhan; Bahar, Md Mezbaul; Labbate, Maurizio; Krishnan, Kannan; Andrews, Stuart; Naidu, Ravi; Megharaj, Mallavarapu

2017-02-01

Contamination of land and water caused by heavy metal mercury (Hg) poses a serious threat to biota worldwide. The seriousness of toxicity of this neurotoxin is characterized by its ability to augment in food chains and bind to thiol groups in living tissue. Therefore, different remediation approaches have been implemented to rehabilitate Hg-contaminated sites. Bioremediation is considered as cheaper and greener technology than the conventional physico-chemical means. Large-scale use of Hg-volatilizing bacteria are used to clean up Hg-contaminated waters, but there is no such approach to remediate Hg-contaminated soils. This review focuses on recent uses of Hg-resistant bacteria in bioremediation of mercury-contaminated sites, limitation and advantages of this approach, and identifies the gaps in existing research.

Is it possible to increase bioavailability but not environmental risk of PAHs in bioremediation?

PubMed

Ortega-Calvo, J J; Tejeda-Agredano, M C; Jimenez-Sanchez, C; Congiu, E; Sungthong, R; Niqui-Arroyo, J L; Cantos, M

2013-10-15

The current poor predictability of end points associated with the bioremediation of polycyclic aromatic hydrocarbons (PAHs) is a large limitation when evaluating its viability for treating contaminated soils and sediments. However, we have seen a wide range of innovations in recent years, such as an the improved use of surfactants, the chemotactic mobilization of bacterial inoculants, the selective biostimulation at pollutant interfaces, rhizoremediation and electrobioremediation, which increase the bioavailability of PAHs but do not necessarily increase the risk to the environment. The integration of these strategies into practical remediation protocols would be beneficial to the bioremediation industry, as well as improve the quality of the environment. Copyright © 2013 Elsevier B.V. All rights reserved.

Effect of saline waste solution infiltration rates on uranium retention and spatial distribution in Hanford sediments.

PubMed

Wan, Jiamin; Tokunaga, Tetsu K; Kim, Yongman; Wang, Zheming; Lanzirotti, Antonio; Saiz, Eduardo; Serne, R Jeffrey

2008-03-15

The accidental overfilling of waste liquid from tank BX-102 at the Hanford Site in 1951 put about 10 t of U(VI) into the vadose zone. In order to understand the dominant geochemical reactions and transport processes that occurred during the initial infiltration and to help understand current spatial distribution, we simulated the waste liquid spilling event in laboratory sediment columns using synthesized metal waste solution. We found that, as the plume propagated through sediments, pH decreased greatly (as much as 4 units) at the moving plume front. Infiltration flow rates strongly affect U behavior. Slower flow rates resulted in higher sediment-associated U concentrations, and higher flow rates (> or =5 cm/day) permitted practically unretarded U transport. Therefore, given the very high Ksat of most of Hanford formation, the low permeability zones within the sediment could have been most important in retaining high concentrations of U during initial release into the vadose zone. Massive amount of colloids, including U-colloids, formed at the plume fronts. Total U concentrations (aqueous and colloid) within plume fronts exceeded the source concentration by up to 5-fold. Uranium colloid formation and accumulation at the neutralized plume front could be one mechanism responsible for highly heterogeneous U distribution observed in the contaminated Hanford vadose zone.

Physicochemical heterogeneity controls on uranium bioreduction rates at the field scale.

PubMed

Li, Li; Gawande, Nitin; Kowalsky, Michael B; Steefel, Carl I; Hubbard, Susan S

2011-12-01

It has been demonstrated in laboratory systems that U(VI) can be reduced to immobile U(IV) by bacteria in natural environments. The ultimate efficacy of bioreduction at the field scale, however, is often challenging to quantify and depends on site characteristics. In this work, uranium bioreduction rates at the field scale are quantified, for the first time, using an integrated approach. The approach combines field data, inverse and forward hydrological and reactive transport modeling, and quantification of reduction rates at different spatial scales. The approach is used to explore the impact of local scale (tens of centimeters) parameters and processes on field scale (tens of meters) system responses to biostimulation treatments and the controls of physicochemical heterogeneity on bioreduction rates. Using the biostimulation experiments at the Department of Energy Old Rifle site, our results show that the spatial distribution of hydraulic conductivity and solid phase mineral (Fe(III)) play a critical role in determining the field-scale bioreduction rates. Due to the dependence on Fe-reducing bacteria, field-scale U(VI) bioreduction rates were found to be largely controlled by the abundance of Fe(III) minerals at the vicinity of the injection wells and by the presence of preferential flow paths connecting injection wells to down gradient Fe(III) abundant areas.

Metagenomic analysis of the bioremediation of diesel-contaminated Canadian high arctic soils.

PubMed

Yergeau, Etienne; Sanschagrin, Sylvie; Beaumier, Danielle; Greer, Charles W

2012-01-01

As human activity in the Arctic increases, so does the risk of hydrocarbon pollution events. On site bioremediation of contaminated soil is the only feasible clean up solution in these remote areas, but degradation rates vary widely between bioremediation treatments. Most previous studies have focused on the feasibility of on site clean-up and very little attention has been given to the microbial and functional communities involved and their ecology. Here, we ask the question: which microorganisms and functional genes are abundant and active during hydrocarbon degradation at cold temperature? To answer this question, we sequenced the soil metagenome of an ongoing bioremediation project in Alert, Canada through a time course. We also used reverse-transcriptase real-time PCR (RT-qPCR) to quantify the expression of several hydrocarbon-degrading genes. Pseudomonas species appeared as the most abundant organisms in Alert soils right after contamination with diesel and excavation (t = 0) and one month after the start of the bioremediation treatment (t = 1m), when degradation rates were at their highest, but decreased after one year (t = 1y), when residual soil hydrocarbons were almost depleted. This trend was also reflected in hydrocarbon degrading genes, which were mainly affiliated with Gammaproteobacteria at t = 0 and t = 1m and with Alphaproteobacteria and Actinobacteria at t = 1y. RT-qPCR assays confirmed that Pseudomonas and Rhodococcus species actively expressed hydrocarbon degradation genes in Arctic biopile soils. Taken together, these results indicated that biopile treatment leads to major shifts in soil microbial communities, favoring aerobic bacteria that can degrade hydrocarbons.

Metagenomic Analysis of the Bioremediation of Diesel-Contaminated Canadian High Arctic Soils

PubMed Central

Yergeau, Etienne; Sanschagrin, Sylvie; Beaumier, Danielle; Greer, Charles W.

2012-01-01

As human activity in the Arctic increases, so does the risk of hydrocarbon pollution events. On site bioremediation of contaminated soil is the only feasible clean up solution in these remote areas, but degradation rates vary widely between bioremediation treatments. Most previous studies have focused on the feasibility of on site clean-up and very little attention has been given to the microbial and functional communities involved and their ecology. Here, we ask the question: which microorganisms and functional genes are abundant and active during hydrocarbon degradation at cold temperature? To answer this question, we sequenced the soil metagenome of an ongoing bioremediation project in Alert, Canada through a time course. We also used reverse-transcriptase real-time PCR (RT-qPCR) to quantify the expression of several hydrocarbon-degrading genes. Pseudomonas species appeared as the most abundant organisms in Alert soils right after contamination with diesel and excavation (t = 0) and one month after the start of the bioremediation treatment (t = 1m), when degradation rates were at their highest, but decreased after one year (t = 1y), when residual soil hydrocarbons were almost depleted. This trend was also reflected in hydrocarbon degrading genes, which were mainly affiliated with Gammaproteobacteria at t = 0 and t = 1m and with Alphaproteobacteria and Actinobacteria at t = 1y. RT-qPCR assays confirmed that Pseudomonas and Rhodococcus species actively expressed hydrocarbon degradation genes in Arctic biopile soils. Taken together, these results indicated that biopile treatment leads to major shifts in soil microbial communities, favoring aerobic bacteria that can degrade hydrocarbons. PMID:22253877

Bioremediation of chromium by novel strains Enterobacter aerogenes T2 and Acinetobacter sp. PD 12 S2.

PubMed

Panda, Jigisha; Sarkar, Priyabrata

2012-06-01

This study had an objective to identify the most potent chromium-resistant bacteria isolated from tannery effluent and apply them for bioremediation of chromium in tannery effluents. Two such strains (previously characterized and identified by us)--Enterobacter aerogenes (NCBI GenBank USA Accession no. GU265554) and Acinetobacter sp. PD 12 (NCBI GenBank USA Accession no. GU084179)--showed powerful chromium resistivity and bioremediation capabilities among many stains isolated from tannery waste. Parameters such as pH, concentration of hexavalent chromium or Cr (VI), and inoculum volume were varied to observe optimum bioconversion and bioaccumulation of Cr (VI) when the said strains were grown in M9 minimal salt media. E. aerogenes was used to remediate chromium from tannery effluents in a laboratory level experiment. Observation by Scanning Electron Microscope and chromium peak in Energy Dispersive X-ray Spectroscopic microanalysis revealed that E. aerogenes helped remediate a moderate amount of Cr (VI) (8-16 mg L(-1)) over a wide range of pH values at 35-37°C (within 26.05 h). High inoculum percentage of Acinetobacter sp. PD 12 also enabled bioremediation of 8-16 mg L(-1) of Cr (VI) over a wide range of temperature (25-37°C), mainly at pH 7 (within 63.28 h). The experiment with real tannery effluent gave very encouraging results. The strain E. aerogenes can be used in bioremediation of Cr (VI) since it could work in actual environmental conditions with extraordinarily high capacity.

Biodegradation Rates Assessment For An In Situ Bioremediation Process

NASA Astrophysics Data System (ADS)

Troquet, J.; Poutier, F.

Bioremediation methods seem a promising way of dealing with soil and subsoil con- tamination by organic substances. The biodegradation process is supported by micro- organisms which use the organic carbon from the pollutants as energy source and cells building blocks. However, bioremediation is not yet universally understood and its success is still an intensively debated issue because all soils and groundwater are not able to sustain biological growth and, then, cannot be successfully bioremediated. The outcome of each degradation process depends on several factors, which, such as oxygen transfer and pollutant bio-availability, can be controlled and are therefore key variables of such bioremediation processes. Then, it is essential to carry out a fea- sibility study based on pilot-testing before starting a remediation project in order to determine the best formulation of nutrients and bacteria to use for the specific condi- tions encountered. The scope of this work is to study the main parameters of the process and its physi- cal limiting steps in order to determine the biodegradation rates in a specific case of contamination. Several ground samples from an actual petroleum hydrocarbon con- taminated site have been laboratory tested. Five fixed bed column reactors, enabling the study of the influence of the different op- erating variables on the biodegradation kinetics, are used. The stoichiometric equation for bacteria growth and pollutant degradation has been established, allowing the de- termination of mass balances. Biodegradation monitoring is achieved by continuously measuring the emissions of carbon dioxide production and intermittently by analysing residual hydrocarbons. Results lead to the knowledge of biodegradation rates which allow to determine the treatment duration and cost.

Importance of organic amendment characteristics on bioremediation of PAH-contaminated soil.

PubMed

Lukić, B; Huguenot, D; Panico, A; Fabbricino, M; van Hullebusch, E D; Esposito, G

2016-08-01

This study investigates the importance of the organic matter characteristics of several organic amendments (i.e., buffalo manure, food and kitchen waste, fruit and vegetables waste, and activated sewage sludge) and their influence in the bioremediation of a polycyclic aromatic hydrocarbons (PAH)-contaminated soil. The removal of low molecular weights (LMW) and high molecular weights (HMW) PAHs was monitored in four bioremediation reactors and used as an indicator of the role of organic amendments in contaminant removal. The total initial concentration of LMW PAHs was 234 mg kg(-1) soil (dry weight), while the amount for HMW PAHs was 422 mg kg(-1) soil (dry weight). Monitoring of operational parameters and chemical analysis was performed during 20 weeks. The concentrations of LMW PAH residues in soil were significantly lower in reactors that displayed a mesophilic phase, i.e., 11 and 15 %, compared to reactors that displayed a thermophilic phase, i.e., 29 and 31 %. Residual HMW PAHs were up to five times higher compared to residual LMW PAHs, depending on the reactor. This demonstrated that the amount of added organic matter and macronutrients such as nitrogen and phosphorus, the biochemical organic compound classes (mostly soluble fraction and proteins), and the operational temperature are important factors affecting the overall efficiency of bioremediation. On that basis, this study shows that characterization of biochemical families could contribute to a better understanding of the effects of organic amendments and clarify their different efficiency during a bioremediation process of PAH-contaminated soil.

Semi-solid state bioremediation of CCA-treated wood using malted barley as a nutrient source

Treesearch

Carol A. Clausen

2002-01-01

Bioremediation processes for recovery and reuse of CCA-treated wood invariably increase the cost of any secondary products manufactured from the remediated fiber. Microbial remediation using either bacteria or fungi has been shown to remove heavy metals from CCA-treated southern yellow pine (SYP). In a two-step remediation process utilizing oxalic acid extraction and...

Laboratory method used for bioremediation

DOEpatents

Carman, M. Leslie; Taylor, Robert T.

2000-01-01

An improved method for in situ microbial filter bioremediation having increasingly operational longevity of an in situ microbial filter emplaced into an aquifer. A method for generating a microbial filter of sufficient catalytic density and thickness, which has increased replenishment interval, improved bacteria attachment and detachment characteristics and the endogenous stability under in situ conditions. A system for in situ field water remediation.

In situ microbial filter used for bioremediation

DOEpatents

Carman, M. Leslie; Taylor, Robert T.

2000-01-01

An improved method for in situ microbial filter bioremediation having increasingly operational longevity of an in situ microbial filter emplaced into an aquifer. A method for generating a microbial filter of sufficient catalytic density and thickness, which has increased replenishment interval, improved bacteria attachment and detachment characteristics and the endogenous stability under in situ conditions. A system for in situ field water remediation.

TREATABILITY STUDY REPORT OF GREEN MOUNTAIN LABORATORIES, INC.'S BIOREMEDIATION PROCESS, TREATMENT OF PCB CONTAMINATED SOILS, AT BEEDE WASTE OIL/CASH ENERGY SUPERFUND SITE, PLAISTOW, NEW HAMPSHIRE

EPA Science Inventory

In 1998, Green Mountain Laboratories, Inc. (GML) and the USEPA agreed to carry out a Superfund Innovative Technology Evaluation (SITE) project to evaluate the effectiveness of GML's Bioremediation Process for the treatment of PCB contaminated soils at the Beede Waste Oil/Cash Ene...