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Author Yabusaki, S.B.; Fang, Y.; Long, P.E.; Resch, C.T.; Peacock, A.D.; Komlos, J.; Jaffe, P.R.; Morrison, S.J.; Dayvault, R.D.; White, D.C.; Anderson, R.T.
Title Uranium removal from groundwater via in situ biostimulation: Field-scale modeling of transport and biological processes Type Journal Article
Year 2007 Publication Journal of Contaminant Hydrology Abbreviated Journal
Volume 93 Issue (down) 1 Pages 216-235
Keywords Bioremediation, Biostimulation, Field experiment, Iron, Reactive transport, Sulfate, Uranium
Abstract During 2002 and 2003, bioremediation experiments in the unconfined aquifer of the Old Rifle UMTRA field site in western Colorado provided evidence for the immobilization of hexavalent uranium in groundwater by iron-reducing Geobacter sp. stimulated by acetate amendment. As the bioavailable Fe(III) terminal electron acceptor was depleted in the zone just downgradient of the acetate injection gallery, sulfate-reducing organisms came to dominate the microbial community. In the present study, we use multicomponent reactive transport modeling to analyze data from the 2002 field experiment to identify the dominant transport and biological processes controlling uranium mobility during biostimulation, and determine field-scale parameters for these modeled processes. The coupled process simulation approach was able to establish a quantitative characterization of the principal flow, transport, and reaction processes based on the 2002 field experiment, that could be applied without modification to describe the 2003 field experiment. Insights gained from this analysis include field-scale estimates of the bioavailable Fe(III) mineral threshold for the onset of sulfate reduction, and rates for the Fe(III), U(VI), and sulfate terminal electron accepting processes.
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ISSN 0169-7722 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ yabusaki_uranium_2007 Serial 156
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Author Gómez, P.; Garralón, A.; Buil, B.; Turrero, M.J.; Sánchez, L.; Cruz, B. de la
Title Modeling of geochemical processes related to uranium mobilization in the groundwater of a uranium mine Type Journal Article
Year 2006 Publication Science of The Total Environment Abbreviated Journal
Volume 366 Issue (down) 1 Pages 295-309
Keywords Geochemical modeling, Granite, Groundwater, Uranium mine, Uranium retention
Abstract This paper describes the processes leading to uranium distribution in the groundwater of five boreholes near a restored uranium mine (dug in granite), and the environmental impact of restoration work in the discharge area. The groundwater uranium content varied from \textless1 μg/L in reduced water far from the area of influence of the uranium ore-containing dyke, to 104 μg/L in a borehole hydraulically connected to the mine. These values, however, fail to reflect a chemical equilibrium between the water and the pure mineral phases. A model for the mobilization of uranium in this groundwater is therefore proposed. This involves the percolation of oxidized waters through the fractured granite, leading to the oxidation of pyrite and arsenopyrite and the precipitation of iron oxyhydroxides. This in turn leads to the dissolution of the primary pitchblende and, subsequently, the release of U(VI) species to the groundwater. These U(VI) species are retained by iron hydroxides. Secondary uranium species are eventually formed as reducing conditions are re-established due to water–rock interactions.
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ISSN 0048-9697 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ gomez_modeling_2006 Serial 162
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Author Edmunds, W.M.; Shand, P.; Hart, P.; Ward, R.S.
Title The natural (baseline) quality of groundwater: a UK pilot study Type Journal Article
Year 2003 Publication Science of The Total Environment Abbreviated Journal
Volume 310 Issue (down) 1 Pages 25-35
Keywords Baseline quality, Groundwater, Hydrogeochemistry, Monitoring, Water Policy
Abstract Knowledge of the natural baseline quality of groundwaters is an essential prerequisite for understanding pollution and for imposing regulatory limits. The natural baseline of groundwaters may show a range of concentrations depending on aquifer mineralogy, facies changes, flow paths and residence time. The geochemical controls on natural concentrations are discussed and an approach to defining baseline concentrations using geochemical and statistical tools is proposed. The approach is illustrated using a flowline from the Chalk aquifer in Berkshire, UK where aerobic and anaerobic sections of the aquifer are separately considered. The baseline concentrations for some elements are close to atmospheric values whereas others evolve through time-dependent water–rock interaction. Certain solutes (K, NH4+), often considered contaminants, reach naturally high concentrations due to geochemical controls; transition metal concentrations are generally low, although their concentrations may be modified by redox controls. It is recommended that the baseline approach be incorporated into future management strategies, notably monitoring.
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ISSN 0048-9697 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ edmunds_natural_2003 Serial 166
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Author Min, M.; Chen, J.; Wang, J.; Wei, G.; Fayek, M.
Title Mineral paragenesis and textures associated with sandstone-hosted roll-front uranium deposits, NW China Type Journal Article
Year 2005 Publication Ore Geology Reviews Abbreviated Journal
Volume 26 Issue (down) 1 Pages 51-69
Keywords China, Mineralogy, Paragenesis, Sandstone-hosted roll-type uranium deposit
Abstract We present a first paragenetic study of the Wuyier, Wuyisan, Wuyiyi and Shihongtan sandstone-hosted roll-front uranium deposits, northwest China. The mineralization is hosted by Lower–Middle Jurassic coarse- to medium-grained sandstones, which are dark-gray to black due to a mixture of ore minerals and carbonaceous debris. The sandstone is alluvial fan-braided river facies. Minerals associated with these deposits can be broadly categorized as detrital, authigenic, and ore-stage mineralization. Ore minerals consist of uraninite and coffinite. This is the first noted occurrence of coffinite in this type of deposit in China. Sulfide minerals associated with the uranium minerals are pyrite, marcasite, and less commonly, sphalerite and galena. The sulfide minerals are largely in textural equilibrium with the uranium minerals. However, these sulfide minerals occasionally appear to predate, as well as postdate, the uranium minerals. This implies that there are multiple generations of sulfides associated with these deposits. The ore minerals occur interstitially between fossilized wood cells in the sandstones as well as replace fossilized wood and biotite. The deposits are generally low-grade. Primary uranium minerals associated with the low-grade deposits are generally too small, ranging from 0.2 to 0.3 μm in diameter, to be observed by optical microscopy and are only observed by electron microscopy. Mineral paragenesis and textures indicate that these deposits formed under low temperature (30–50 °C) conditions.
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ISSN 0169-1368 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ min_mineral_2005 Serial 175
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Author Uhrie, J.L.; Drever, J.I.; Colberg, P.J.S.; Nesbitt, C.C.
Title In situ immobilization of heavy metals associated with uranium leach mines by bacterial sulfate reduction Type Journal Article
Year 1996 Publication Hydrometallurgy Abbreviated Journal
Volume 43 Issue (down) 1 Pages 231-239
Keywords
Abstract Laboratory experiments with mixed populations of sulfate-reducing bactreria were shown to mediate the removal of milligrams/liter concentrations of uranium, selenium, arsenic and vanadium from aqueous solution via reduction, precipitation and adsorption. Results of laboratory experiments with active sulfidogenic biomass suggest that injection of sulfate and a source of carbon could enhance anaerobic microbial activity in and around uranium leach mines leading to in situ immobilization contaminating metals.
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ISSN 0304-386x ISBN Medium
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Notes Approved no
Call Number THL @ christoph.kuells @ uhrie_situ_1996 Serial 197
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Author Heaton, T.H.E.
Title Sources of the nitrate in phreatic groundwater in the western Kalahari Type Journal Article
Year 1984 Publication Journal of Hydrology Abbreviated Journal
Volume 67 Issue (down) 1 Pages 249-259
Keywords
Abstract Elevated levels of nitrate occur in phreatic groundwater in the western Kalahari, Namibia. Nitrate in water containing 0.4–3.1 meq NO−3l−1, of widespread occurrence, has δ15N values in the range +4.9 to +8.0‰, suggesting natural derivation from the soil. The sporadic occurrence of very high levels of nitrate (> 4 meq NO−3l−1), which has δ15N between +9.3 to +18.7‰, reflects pollution derived from animal waste. The importance of considering the possible isotopic effects of denitrification, and the significance of leaching in the nitrogen budget of the Kalahari soil, are also discussed.
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ISSN 0022-1694 ISBN Medium
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Notes Approved no
Call Number THL @ christoph.kuells @ Heaton1984249 Serial 278
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Author Heaton, T.H.E.; Talma, A.S.; Vogel, J.C.
Title Origin and history of nitrate in confined groundwater in the western Kalahari Type Journal Article
Year 1983 Publication Journal of Hydrology Abbreviated Journal
Volume 62 Issue (down) 1 Pages 243-262
Keywords
Abstract Data are presented for nitrate, dinitrogen and argon concentrations and 15N14N ratios in groundwater, with radiocarbon ages up to 40,000 yr. for three confined sandstone aquifers in the western Kalahari of South West Africa/Namibia. The nitrate is probably generated within the soil of the recharge areas, and its production rate during the period 3000-40,000 B.P. has remained between 0.5 and 1.6 meq NO−3l−1 of recharge water, with ° 15N between + 4 and + 8‰. Variations in the amount of nitrate and of “excess air” in groundwater recharge are found, and can only reflect changes in the environmental conditions during recharge. They must therefore be caused by the climatic changes that have taken place during the past 25,000 yr.
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ISSN 0022-1694 ISBN Medium
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Notes Approved no
Call Number THL @ christoph.kuells @ Heaton1983243 Serial 282
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Author Rajfur, M.; Kłos, A.; Wacławek, M.
Title Sorption properties of algae Spirogyra sp. and their use for determination of heavy metal ions concentrations in surface water Type Journal Article
Year 2010 Publication Bioelectrochemistry Abbreviated Journal
Volume 80 Issue (down) 1 Pages 81-86
Keywords Biomonitoring, Heavy metal ions, Algae sp., Sorption kinetics, Langmuir isotherm
Abstract Kinetics of heavy-metal ions sorption by alga Spirogyra sp. was evaluated experimentally in the laboratory, using both the static and the dynamic approach. The metal ions – Mn2+, Cu2+, Zn2+ and Cd2+ – were sorbed from aqueous solutions of their salts. The static experiments showed that the sorption equilibria were attained in 30min, with 90-95% of metal ions sorbed in first 10min of each process. The sorption equilibria were approximated with the Langmuir isotherm model. The algae sorbed each heavy metal ions proportionally to the amount of this metal ions in solution. The experiments confirmed that after 30min of exposition to contaminated water, the concentration of heavy metal ions in the algae, which initially contained small amounts of these metal ions, increased proportionally to the concentration of metal ions in solution. The presented results can be used for elaboration of a method for classification of surface waters that complies with the legal regulations.
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ISSN 1567-5394 ISBN Medium
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Notes A Selection of Papers presented at the 4th International Workshop on Surface Modification for Chemical and Biochemical Sensing (SMCBS 2009) Approved no
Call Number THL @ christoph.kuells @ Rajfur201081 Serial 283
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Author Adolph, G.; KÜlls, C.; Willscheid, A.
Title Determination and validation of age structures as an improved measure of hydrological dynamics Type Conference Article
Year 2007 Publication Geophysical Research Abstracts Abbreviated Journal
Volume 9 Issue (down) 08013 Pages
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Call Number THL @ christoph.kuells @ Adolph2007determination Serial 58
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Author Doulgeris, C.; Tziritis, E.; Pisinaras, V.; Panagopoulos, A.; Külls, C.
Title Prediction of seawater intrusion to coastal aquifers based on non-dimensional diagrams Type Conference Article
Year 2020 Publication EGU Geophysical Abstracts Abbreviated Journal
Volume Issue (down) Pages 4073
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Call Number THL @ christoph.kuells @ Doulgeris2020prediction Serial 41
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