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Title: In Situ Bioreduction of Uranium (VI) to Submicromolar Levels and Reoxidation by Dissolved Oxygen

Abstract

Groundwater within Area 3 of the U.S. Department of Energy (DOE) Environmental Remediation Sciences Program (ERSP) Field Research Center at Oak Ridge, TN (ORFRC) contains up to 135 {micro}M uranium as U(VI). Through a series of experiments at a pilot scale test facility, we explored the lower limits of groundwater U(VI) that can be achieved by in-situ biostimulation and the effects of dissolved oxygen on immobilized uranium. Weekly 2 day additions of ethanol over a 2-year period stimulated growth of denitrifying, Fe(III)-reducing, and sulfate-reducing bacteria, and immobilization of uranium as U(IV), with dissolved uranium concentrations decreasing to low levels. Following sulfite addition to remove dissolved oxygen, aqueous U(VI) concentrations fell below the U.S. Environmental Protection Agency maximum contaminant limit (MCL) for drinking water (<30 {micro}g L{sup -1} or 0.126 {micro}M). Under anaerobic conditions, these low concentrations were stable, even in the absence of added ethanol. However, when sulfite additions stopped, and dissolved oxygen (4.0-5.5 mg L{sup -1}) entered the injection well, spatially variable changes in aqueous U(VI) occurred over a 60 day period, with concentrations increasing rapidly from <0.13 to 2.0 {micro}M at a multilevel sampling (MLS) well located close to the injection well, but changing little at an MLSmore » well located further away. Resumption of ethanol addition restored reduction of Fe(III), sulfate, and U(VI) within 36 h. After 2 years of ethanol addition, X-ray absorption near-edge structure spectroscopy (XANES) analyses indicated that U(IV) comprised 60-80% of the total uranium in sediment samples. At the completion of the project (day 1260), U concentrations in MLS wells were less than 0.1 {micro}M. The microbial community at MLS wells with low U(VI) contained bacteria that are known to reduce uranium, including Desulfovibrio spp. and Geobacter spp., in both sediment and groundwater. The dominant Fe(III)-reducing species were Geothrix spp.« less

Authors:
 [1];  [1];  [2];  [2];  [3];  [3];  [4];  [5];  [1];  [6];  [6];  [1];  [1];  [1];  [1];  [1];  [4];  [1];  [1];  [5] more »;  [3];  [3];  [6];  [2];  [2];  [1];  [1] « less
  1. ORNL
  2. Stanford University
  3. Michigan State University, East Lansing
  4. Miami University, Oxford, OH
  5. Argonne National Laboratory (ANL)
  6. University of Oklahoma, Norman
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
945330
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Environmental Science & Technology; Journal Volume: 41; Journal Issue: 16
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; URANIUM; IN-SITU PROCESSING; BIODEGRADATION; REDUCTION; GROUND WATER; OAK RIDGE RESERVATION; BACTERIA; ETHANOL

Citation Formats

Wu, Weimin, Carley, Jack M, Luo, Jian, Ginder-Vogel, Matthew A., Cardenas, Erick, Leigh, Mary Beth, Hwang, Chaichi, Kelly, Shelly D, Ruan, Chuanmin, Wu, Liyou, Van Nostrand, Joy, Gentry, Terry J, Lowe, Kenneth Alan, Mehlhorn, Tonia L, Carroll, Sue L, Luo, Wensui, Fields, Matthew Wayne, Gu, Baohua, Watson, David B, Kemner, Kenneth M, Marsh, Terence, Tiedje, James, Zhou, Jizhong, Fendorf, Scott, Kitanidis, Peter K., Jardine, Philip M, and Criddle, Craig. In Situ Bioreduction of Uranium (VI) to Submicromolar Levels and Reoxidation by Dissolved Oxygen. United States: N. p., 2007. Web. doi:10.1021/es062657b.
Wu, Weimin, Carley, Jack M, Luo, Jian, Ginder-Vogel, Matthew A., Cardenas, Erick, Leigh, Mary Beth, Hwang, Chaichi, Kelly, Shelly D, Ruan, Chuanmin, Wu, Liyou, Van Nostrand, Joy, Gentry, Terry J, Lowe, Kenneth Alan, Mehlhorn, Tonia L, Carroll, Sue L, Luo, Wensui, Fields, Matthew Wayne, Gu, Baohua, Watson, David B, Kemner, Kenneth M, Marsh, Terence, Tiedje, James, Zhou, Jizhong, Fendorf, Scott, Kitanidis, Peter K., Jardine, Philip M, & Criddle, Craig. In Situ Bioreduction of Uranium (VI) to Submicromolar Levels and Reoxidation by Dissolved Oxygen. United States. doi:10.1021/es062657b.
Wu, Weimin, Carley, Jack M, Luo, Jian, Ginder-Vogel, Matthew A., Cardenas, Erick, Leigh, Mary Beth, Hwang, Chaichi, Kelly, Shelly D, Ruan, Chuanmin, Wu, Liyou, Van Nostrand, Joy, Gentry, Terry J, Lowe, Kenneth Alan, Mehlhorn, Tonia L, Carroll, Sue L, Luo, Wensui, Fields, Matthew Wayne, Gu, Baohua, Watson, David B, Kemner, Kenneth M, Marsh, Terence, Tiedje, James, Zhou, Jizhong, Fendorf, Scott, Kitanidis, Peter K., Jardine, Philip M, and Criddle, Craig. Mon . "In Situ Bioreduction of Uranium (VI) to Submicromolar Levels and Reoxidation by Dissolved Oxygen". United States. doi:10.1021/es062657b.
@article{osti_945330,
title = {In Situ Bioreduction of Uranium (VI) to Submicromolar Levels and Reoxidation by Dissolved Oxygen},
author = {Wu, Weimin and Carley, Jack M and Luo, Jian and Ginder-Vogel, Matthew A. and Cardenas, Erick and Leigh, Mary Beth and Hwang, Chaichi and Kelly, Shelly D and Ruan, Chuanmin and Wu, Liyou and Van Nostrand, Joy and Gentry, Terry J and Lowe, Kenneth Alan and Mehlhorn, Tonia L and Carroll, Sue L and Luo, Wensui and Fields, Matthew Wayne and Gu, Baohua and Watson, David B and Kemner, Kenneth M and Marsh, Terence and Tiedje, James and Zhou, Jizhong and Fendorf, Scott and Kitanidis, Peter K. and Jardine, Philip M and Criddle, Craig},
abstractNote = {Groundwater within Area 3 of the U.S. Department of Energy (DOE) Environmental Remediation Sciences Program (ERSP) Field Research Center at Oak Ridge, TN (ORFRC) contains up to 135 {micro}M uranium as U(VI). Through a series of experiments at a pilot scale test facility, we explored the lower limits of groundwater U(VI) that can be achieved by in-situ biostimulation and the effects of dissolved oxygen on immobilized uranium. Weekly 2 day additions of ethanol over a 2-year period stimulated growth of denitrifying, Fe(III)-reducing, and sulfate-reducing bacteria, and immobilization of uranium as U(IV), with dissolved uranium concentrations decreasing to low levels. Following sulfite addition to remove dissolved oxygen, aqueous U(VI) concentrations fell below the U.S. Environmental Protection Agency maximum contaminant limit (MCL) for drinking water (<30 {micro}g L{sup -1} or 0.126 {micro}M). Under anaerobic conditions, these low concentrations were stable, even in the absence of added ethanol. However, when sulfite additions stopped, and dissolved oxygen (4.0-5.5 mg L{sup -1}) entered the injection well, spatially variable changes in aqueous U(VI) occurred over a 60 day period, with concentrations increasing rapidly from <0.13 to 2.0 {micro}M at a multilevel sampling (MLS) well located close to the injection well, but changing little at an MLS well located further away. Resumption of ethanol addition restored reduction of Fe(III), sulfate, and U(VI) within 36 h. After 2 years of ethanol addition, X-ray absorption near-edge structure spectroscopy (XANES) analyses indicated that U(IV) comprised 60-80% of the total uranium in sediment samples. At the completion of the project (day 1260), U concentrations in MLS wells were less than 0.1 {micro}M. The microbial community at MLS wells with low U(VI) contained bacteria that are known to reduce uranium, including Desulfovibrio spp. and Geobacter spp., in both sediment and groundwater. The dominant Fe(III)-reducing species were Geothrix spp.},
doi = {10.1021/es062657b},
journal = {Environmental Science & Technology},
number = 16,
volume = 41,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}