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Title: Biostimulation of Iron Reduction and Uranium Immobilization: Microbial and Mineralogical Controls

Abstract

The overall objective of our project is to understand the microbial and geochemical mechanisms controlling the reduction and immobilization of U(VI) during biostimulation in subsurface sediments of the Field Research Center (FRC) which are cocontaminated with uranium and nitrate. The focus will be on activity of microbial populations (metal- and nitrate-reducing bacteria) and iron minerals which are likely to make strong contributions to the fate of uranium during in situ bioremediation. The project will: (1) quantify the relationships between active members of the microbial communities, iron mineralogy, and nitrogen transformations in the field and in laboratory incubations under a variety of biostimulation conditions, (2) purify and physiologically characterize new model metal-reducing bacteria isolated from moderately acidophilic FRC subsurface sediments, and (3) elucidate the biotic and abiotic mechanisms by which FRC aluminosilicate clay minerals are reduced and dissolved under environmental conditions resembling those during biostimulation. Active microbial communities will be assessed using quantitative molecular techniques along with geochemical measurements to determine the different terminal-electron-accepting pathways. Iron minerals will be characterized using a suite of physical, spectroscopic, and wet chemical methods. Monitoring the activity and composition of the denitrifier community in parallel with denitrification intermediates during nitrate removal will provide a bettermore » understanding of the indirect effects of nitrate reduction on uranium speciation. Through quantification of the activity of specific microbial populations and an in-depth characterization of Fe minerals likely to catalyze U sorption/precipitation, we will provide important inputs for reaction-based biogeochemical models which will provide the basis for development of in situ U bioremediation strategies. In collaboration with Jack Istok and Lee Krumholz, we have begun to study the change in microbial community composition of FRC sediments during in situ biostimulation in single well push-pull tests. Microbial communities were stimulated in the acidic subsurface via pH neutralization and addition of electron donor to wells. Examination of sediment chemistry in cores sampled immediately adjacent to treated wells revealed that sediment pH increased substantially (by 1-2 pH units), while nitrate was largely depleted. Following the in situ biostimulation, previously cultured metal-reducing {delta}-Proteobacteria 16S rRNA gene sequences substantially increased from 5% to nearly 40% of clone libraries. Quantitative PCR revealed that Geobacter-type 16S rRNA gene sequences increased in biostimulated sediments by one to two orders of magnitude at two of the four sites tested, thereby corroborating information obtained from clone libraries, and indicating that members of the {delta}-Proteobacteria (including Anaeromyxobacter dehalogenans-related and Geobacter-related organisms) are important metal-reducing bacteria in FRC.« less

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Florida State University, Tallahassee, FL; University of Illinois, Urbana, IL; Rutgers University, New Brunswick, NJ
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
895386
Report Number(s):
CONF-NABIR2004-33
TRN: US0700453
Resource Type:
Conference
Resource Relation:
Conference: Annual NABIR PI Meeting, March 15-17, 2004, Warrenton, VA
Country of Publication:
United States
Language:
English
Subject:
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY; 54 ENVIRONMENTAL SCIENCES; 59 BASIC BIOLOGICAL SCIENCES; BACTERIA; BINDING ENERGY; BIOREMEDIATION; CHEMISTRY; DENITRIFICATION; ELECTRONS; GENES; IRON; MINERALOGY; MONITORING; NITRATES; NITROGEN; REMOVAL; SEDIMENTS; TRANSFORMATIONS; URANIUM; VALENCE

Citation Formats

Joel E. Kostka, Lainie Petrie, Nadia North, David L. Balkwill, Joseph W. Stucki, and Lee Kerkhof. Biostimulation of Iron Reduction and Uranium Immobilization: Microbial and Mineralogical Controls. United States: N. p., 2004. Web.
Joel E. Kostka, Lainie Petrie, Nadia North, David L. Balkwill, Joseph W. Stucki, & Lee Kerkhof. Biostimulation of Iron Reduction and Uranium Immobilization: Microbial and Mineralogical Controls. United States.
Joel E. Kostka, Lainie Petrie, Nadia North, David L. Balkwill, Joseph W. Stucki, and Lee Kerkhof. Wed . "Biostimulation of Iron Reduction and Uranium Immobilization: Microbial and Mineralogical Controls". United States. doi:. https://www.osti.gov/servlets/purl/895386.
@article{osti_895386,
title = {Biostimulation of Iron Reduction and Uranium Immobilization: Microbial and Mineralogical Controls},
author = {Joel E. Kostka and Lainie Petrie and Nadia North and David L. Balkwill and Joseph W. Stucki and Lee Kerkhof},
abstractNote = {The overall objective of our project is to understand the microbial and geochemical mechanisms controlling the reduction and immobilization of U(VI) during biostimulation in subsurface sediments of the Field Research Center (FRC) which are cocontaminated with uranium and nitrate. The focus will be on activity of microbial populations (metal- and nitrate-reducing bacteria) and iron minerals which are likely to make strong contributions to the fate of uranium during in situ bioremediation. The project will: (1) quantify the relationships between active members of the microbial communities, iron mineralogy, and nitrogen transformations in the field and in laboratory incubations under a variety of biostimulation conditions, (2) purify and physiologically characterize new model metal-reducing bacteria isolated from moderately acidophilic FRC subsurface sediments, and (3) elucidate the biotic and abiotic mechanisms by which FRC aluminosilicate clay minerals are reduced and dissolved under environmental conditions resembling those during biostimulation. Active microbial communities will be assessed using quantitative molecular techniques along with geochemical measurements to determine the different terminal-electron-accepting pathways. Iron minerals will be characterized using a suite of physical, spectroscopic, and wet chemical methods. Monitoring the activity and composition of the denitrifier community in parallel with denitrification intermediates during nitrate removal will provide a better understanding of the indirect effects of nitrate reduction on uranium speciation. Through quantification of the activity of specific microbial populations and an in-depth characterization of Fe minerals likely to catalyze U sorption/precipitation, we will provide important inputs for reaction-based biogeochemical models which will provide the basis for development of in situ U bioremediation strategies. In collaboration with Jack Istok and Lee Krumholz, we have begun to study the change in microbial community composition of FRC sediments during in situ biostimulation in single well push-pull tests. Microbial communities were stimulated in the acidic subsurface via pH neutralization and addition of electron donor to wells. Examination of sediment chemistry in cores sampled immediately adjacent to treated wells revealed that sediment pH increased substantially (by 1-2 pH units), while nitrate was largely depleted. Following the in situ biostimulation, previously cultured metal-reducing {delta}-Proteobacteria 16S rRNA gene sequences substantially increased from 5% to nearly 40% of clone libraries. Quantitative PCR revealed that Geobacter-type 16S rRNA gene sequences increased in biostimulated sediments by one to two orders of magnitude at two of the four sites tested, thereby corroborating information obtained from clone libraries, and indicating that members of the {delta}-Proteobacteria (including Anaeromyxobacter dehalogenans-related and Geobacter-related organisms) are important metal-reducing bacteria in FRC.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Mar 17 00:00:00 EST 2004},
month = {Wed Mar 17 00:00:00 EST 2004}
}

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