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Title: Microbial Methylation of Iodide in Unconfined Aquifer Sediments at the Hanford Site, USA

Abstract

Incomplete knowledge of environmental transformation reactions limits our ability to accurately inventory and predictably model the fate of radioiodine. The most prevalent chemical species of iodine include iodate (IO 3 -), iodide (I -), and organo-iodine. The emission of gaseous species could be significant loss or flux term but these processes have not been investigated at radioiodine impacted sites. We examined iodide methylation and volatilization for Hanford Site sediments from 3 different locations under native and organic substrate amended conditions at 3 iodide concentrations. Aqueous and gaseous sampling revealed methyl-iodide to be the only iodinated compound produced under biotic conditions. No abiotic transformations of iodide were measured. Methyl-iodide was produced by 52 out of 54 microcosms, regardless of prior exposure to iodine contamination or the experimental concentration. Interestingly, iodide volatilization activity was consistently higher under native (oligotrophic) Hanford sediment conditions. Carbon and nutrients were not only unnecessary for microbial activation, but supplementation resulted in > 3 fold reduction in methyl-iodide formation. This investigation not only demonstrates the potential for iodine volatilization in deep, oligotrophic subsurface sediments at a nuclear waste site, but also emphasizes an important role for biotic methylation pathways to the long-term management and monitoring of radioiodine inmore » the environment.« less

Authors:
 [1];  [1];  [1];  [1]; ORCiD logo [1]
  1. Pacific Northwest National Laboratory (PNNL), Richland, WA (United States). Earth Systems Science Div.
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1574898
Report Number(s):
PNNL-SA-143910
Journal ID: ISSN 1664-302X
Grant/Contract Number:  
AC05-76RL01830
Resource Type:
Accepted Manuscript
Journal Name:
Frontiers in Microbiology
Additional Journal Information:
Journal Volume: 10; Journal ID: ISSN 1664-302X
Publisher:
Frontiers Research Foundation
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES

Citation Formats

Bagwell, Christopher E., Zhong, Lirong, Wells, Jacqueline R., Mitroshkov, Alexandre V., and Qafoku, Nikolla P. Microbial Methylation of Iodide in Unconfined Aquifer Sediments at the Hanford Site, USA. United States: N. p., 2019. Web. doi:10.3389/fmicb.2019.02460.
Bagwell, Christopher E., Zhong, Lirong, Wells, Jacqueline R., Mitroshkov, Alexandre V., & Qafoku, Nikolla P. Microbial Methylation of Iodide in Unconfined Aquifer Sediments at the Hanford Site, USA. United States. doi:10.3389/fmicb.2019.02460.
Bagwell, Christopher E., Zhong, Lirong, Wells, Jacqueline R., Mitroshkov, Alexandre V., and Qafoku, Nikolla P. Thu . "Microbial Methylation of Iodide in Unconfined Aquifer Sediments at the Hanford Site, USA". United States. doi:10.3389/fmicb.2019.02460. https://www.osti.gov/servlets/purl/1574898.
@article{osti_1574898,
title = {Microbial Methylation of Iodide in Unconfined Aquifer Sediments at the Hanford Site, USA},
author = {Bagwell, Christopher E. and Zhong, Lirong and Wells, Jacqueline R. and Mitroshkov, Alexandre V. and Qafoku, Nikolla P.},
abstractNote = {Incomplete knowledge of environmental transformation reactions limits our ability to accurately inventory and predictably model the fate of radioiodine. The most prevalent chemical species of iodine include iodate (IO3-), iodide (I-), and organo-iodine. The emission of gaseous species could be significant loss or flux term but these processes have not been investigated at radioiodine impacted sites. We examined iodide methylation and volatilization for Hanford Site sediments from 3 different locations under native and organic substrate amended conditions at 3 iodide concentrations. Aqueous and gaseous sampling revealed methyl-iodide to be the only iodinated compound produced under biotic conditions. No abiotic transformations of iodide were measured. Methyl-iodide was produced by 52 out of 54 microcosms, regardless of prior exposure to iodine contamination or the experimental concentration. Interestingly, iodide volatilization activity was consistently higher under native (oligotrophic) Hanford sediment conditions. Carbon and nutrients were not only unnecessary for microbial activation, but supplementation resulted in > 3 fold reduction in methyl-iodide formation. This investigation not only demonstrates the potential for iodine volatilization in deep, oligotrophic subsurface sediments at a nuclear waste site, but also emphasizes an important role for biotic methylation pathways to the long-term management and monitoring of radioiodine in the environment.},
doi = {10.3389/fmicb.2019.02460},
journal = {Frontiers in Microbiology},
number = ,
volume = 10,
place = {United States},
year = {2019},
month = {10}
}

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    Works referencing / citing this record:

    Comparison of Iodide and Iodate Accumulation and Volatilization by Filamentous Fungi during Static Cultivation
    journal, June 2017

    • Duborská, Eva; Urík, Martin; Bujdoš, Marek
    • Water, Air, & Soil Pollution, Vol. 228, Issue 6
    • DOI: 10.1007/s11270-017-3407-4

    The distribution and transformations of iodine in the environment
    journal, January 1984


    Abiotic formation of organoiodine compounds by manganese dioxide induced iodination of dissolved organic matter
    journal, May 2018


    Reduction of TcO4− by sediment-associated biogenic Fe(II)
    journal, August 2004

    • Fredrickson, James K.; Zachara, John M.; Kennedy, David W.
    • Geochimica et Cosmochimica Acta, Vol. 68, Issue 15
    • DOI: 10.1016/j.gca.2003.10.024

    Sorption and transport of iodine species in sediments from the Savannah River and Hanford Sites
    journal, July 2005


    Sorption and speciation of iodine in groundwater system: The roles of organic matter and organic-mineral complexes
    journal, June 2017


    Radioiodine sorption/desorption and speciation transformation by subsurface sediments from the Hanford Site
    journal, January 2015


    Technetium and iodine aqueous species immobilization and transformations in the presence of strong reductants and calcite-forming solutions: Remedial action implications
    journal, September 2018


    Formation of methyl iodide on a natural manganese oxide
    journal, August 2010


    Incorporation Modes of Iodate in Calcite
    journal, April 2018

    • Kerisit, Sebastien N.; Smith, Frances N.; Saslow, Sarah A.
    • Environmental Science & Technology, Vol. 52, Issue 10
    • DOI: 10.1021/acs.est.8b00339

    Tracing the History of Nuclear Releases:  Determination of 129 I in Tree Rings
    journal, March 2002

    • Rao, Usha; Fehn, Udo; Muramatsu, Yasuyuki
    • Environmental Science & Technology, Vol. 36, Issue 6
    • DOI: 10.1021/es011045i

    Microbial Participation in Iodine Volatilization from Soils
    journal, September 2003

    • Amachi, Seigo; Kasahara, Mizuyo; Hanada, Satoshi
    • Environmental Science & Technology, Vol. 37, Issue 17
    • DOI: 10.1021/es0210751

    Sequestration and Remobilization of Radioiodine ( 129 I) by Soil Organic Matter and Possible Consequences of the Remedial Action at Savannah River Site
    journal, December 2011

    • Xu, Chen; Miller, Eric J.; Zhang, Saijin
    • Environmental Science & Technology, Vol. 45, Issue 23
    • DOI: 10.1021/es201343d

    Iodine-129 and Iodine-127 Speciation in Groundwater at the Hanford Site, U.S.: Iodate Incorporation into Calcite
    journal, August 2013

    • Zhang, Saijin; Xu, Chen; Creeley, Danielle
    • Environmental Science & Technology, Vol. 47, Issue 17
    • DOI: 10.1021/es401816e

    Halocarbons produced by natural oxidation processes during degradation of organic matter
    journal, January 2000

    • Keppler, F.; Eiden, R.; Niedan, V.
    • Nature, Vol. 403, Issue 6767
    • DOI: 10.1038/35002055

    Radioiodine Biogeochemistry and Prevalence in Groundwater
    journal, August 2014

    • Kaplan, D. I.; Denham, M. E.; Zhang, S.
    • Critical Reviews in Environmental Science and Technology, Vol. 44, Issue 20
    • DOI: 10.1080/10643389.2013.828273

    Biospheric 129I Concentrations in the Pre-nuclear and Nuclear Age
    journal, January 1993


    Ectomycorrhizal fungi: A new source of atmospheric methyl halides?
    journal, June 2004


    Emissions of Methyl Halides and Methane from Rice Paddies
    journal, November 2000


    Combining 16S rRNA gene variable regions enables high-resolution microbial community profiling
    journal, January 2018


    Hanford Site Vadose Zone Studies: An Overview
    journal, January 2007

    • Gee, G. W.; Oostrom, M.; Freshley, M. D.
    • Vadose Zone Journal, Vol. 6, Issue 4
    • DOI: 10.2136/vzj2006.0179

    Geochemical Processes Controlling Migration of Tank Wastes in Hanford's Vadose Zone
    journal, January 2007

    • Zachara, John M.; Serne, Jeff; Freshley, Mark
    • Vadose Zone Journal, Vol. 6, Issue 4
    • DOI: 10.2136/vzj2006.0180