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Title: Influence of manganese abundances on iron and arsenic solubility in rice paddy soils

Abstract

Arsenic (As) mobilization in rice paddy soils under fluctuating redox conditions is influenced by the biogeochemical cycling of redox sensitive elements such as iron (Fe) and manganese (Mn). Arsenic mobility in paddy soils is highly variable, and the influence of Mn abundances and Mn/Fe ratios on As mobility in these soils have received little attention. In this contribution, we developed a complementary set of field and laboratory experiments designed to evaluate the impact of Mn on interconnected Fe and As solubilization in rice paddy soils experiencing wetting-drying cycles through controlled irrigation. Porewater monitoring and synchrotron-based imaging and spectroscopy of thin sections prepared from an Arkansas paddy soil confirmed that As release was primarily governed by reductive dissolution of Fe (oxy)hydroxide phases. Experiments with laboratory soil microcosms amended with the synthetic nanocrystalline Mn oxide, δ-MnO 2, showed that higher initial Mn/Fe inhibited Fe and As mobilization into porewater relative to unamended soil by up to 95% and 45%, respectively. Geochemical modeling suggests that pH increases driven by microbial MnO 2 reduction, in conjunction with microbial Fe- and sulfate-reduction in carbonate-rich porewater, enhanced the precipitation of siderite (FeCO 3(s)), mackinawite (FeS (s)), and potentially a Mn(II) arsenate phase. These secondary mineral phasesmore » likely played a greater role in controlling As solubilization than the role of Mn as a redox buffer regulating the redox conditions in the flooded soils. Field and laboratory experiments showed that alternate wetting and drying approaches with a single dry-down can be effective at reducing dissolved As concentrations in porewater through the oxidation of Fe. Differences in soil Mn/Fe ratios had no clear impact on the effectiveness of dry-downs as a strategy to reduce As mobilization.« less

Authors:
 [1]; ORCiD logo [1];  [2]; ORCiD logo [3];  [4];  [4]; ORCiD logo [1]
  1. Cornell Univ., Ithaca, NY (United States). School of Civil and Environmental Engineering
  2. Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source II (NSLS-II)
  3. Univ. of Lausanne (Switzerland)
  4. Dale Bumpers National Rice Research Center, USDA-ARS, Stuttgart, AR (United States)
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
OSTI Identifier:
1618406
Report Number(s):
BNL-215921-2020-JAAM
Journal ID: ISSN 0016-7037
Grant/Contract Number:  
SC0012704
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Geochimica et Cosmochimica Acta
Additional Journal Information:
Journal Volume: 276; Journal Issue: C; Journal ID: ISSN 0016-7037
Publisher:
Elsevier; The Geochemical Society; The Meteoritical Society
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; Rice Paddies; Arsenic; Manganese; Iron; Alternate Wetting and Drying; Redox

Citation Formats

Maguffin, Scott C., Abu-Ali, Lena, Tappero, Ryan V., Pena, Jasquelin, Rohila, Jai S., McClung, Anna M., and Reid, Matthew C. Influence of manganese abundances on iron and arsenic solubility in rice paddy soils. United States: N. p., 2020. Web. doi:10.1016/j.gca.2020.02.012.
Maguffin, Scott C., Abu-Ali, Lena, Tappero, Ryan V., Pena, Jasquelin, Rohila, Jai S., McClung, Anna M., & Reid, Matthew C. Influence of manganese abundances on iron and arsenic solubility in rice paddy soils. United States. doi:10.1016/j.gca.2020.02.012.
Maguffin, Scott C., Abu-Ali, Lena, Tappero, Ryan V., Pena, Jasquelin, Rohila, Jai S., McClung, Anna M., and Reid, Matthew C. Wed . "Influence of manganese abundances on iron and arsenic solubility in rice paddy soils". United States. doi:10.1016/j.gca.2020.02.012.
@article{osti_1618406,
title = {Influence of manganese abundances on iron and arsenic solubility in rice paddy soils},
author = {Maguffin, Scott C. and Abu-Ali, Lena and Tappero, Ryan V. and Pena, Jasquelin and Rohila, Jai S. and McClung, Anna M. and Reid, Matthew C.},
abstractNote = {Arsenic (As) mobilization in rice paddy soils under fluctuating redox conditions is influenced by the biogeochemical cycling of redox sensitive elements such as iron (Fe) and manganese (Mn). Arsenic mobility in paddy soils is highly variable, and the influence of Mn abundances and Mn/Fe ratios on As mobility in these soils have received little attention. In this contribution, we developed a complementary set of field and laboratory experiments designed to evaluate the impact of Mn on interconnected Fe and As solubilization in rice paddy soils experiencing wetting-drying cycles through controlled irrigation. Porewater monitoring and synchrotron-based imaging and spectroscopy of thin sections prepared from an Arkansas paddy soil confirmed that As release was primarily governed by reductive dissolution of Fe (oxy)hydroxide phases. Experiments with laboratory soil microcosms amended with the synthetic nanocrystalline Mn oxide, δ-MnO2, showed that higher initial Mn/Fe inhibited Fe and As mobilization into porewater relative to unamended soil by up to 95% and 45%, respectively. Geochemical modeling suggests that pH increases driven by microbial MnO2 reduction, in conjunction with microbial Fe- and sulfate-reduction in carbonate-rich porewater, enhanced the precipitation of siderite (FeCO3(s)), mackinawite (FeS(s)), and potentially a Mn(II) arsenate phase. These secondary mineral phases likely played a greater role in controlling As solubilization than the role of Mn as a redox buffer regulating the redox conditions in the flooded soils. Field and laboratory experiments showed that alternate wetting and drying approaches with a single dry-down can be effective at reducing dissolved As concentrations in porewater through the oxidation of Fe. Differences in soil Mn/Fe ratios had no clear impact on the effectiveness of dry-downs as a strategy to reduce As mobilization.},
doi = {10.1016/j.gca.2020.02.012},
journal = {Geochimica et Cosmochimica Acta},
issn = {0016-7037},
number = C,
volume = 276,
place = {United States},
year = {2020},
month = {2}
}

Journal Article:
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This content will become publicly available on February 19, 2021
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