Cobalt Distribution and Speciation: Effect of Aging, Intermittent Submergence, In Situ Rice Roots

Beak, Douglas G., Kirby, Jason K., Hettiarachchi, Ganga M., Wendling, Laura A., McLaughlin, Michael J. and Khatiwada, Raju (2010) Cobalt Distribution and Speciation: Effect of Aging, Intermittent Submergence, In Situ Rice Roots. Journal of Environmental Quality, 40 3: 679-695. doi:10.2134/jeq2010.0139


Author Beak, Douglas G.
Kirby, Jason K.
Hettiarachchi, Ganga M.
Wendling, Laura A.
McLaughlin, Michael J.
Khatiwada, Raju
Title Cobalt Distribution and Speciation: Effect of Aging, Intermittent Submergence, In Situ Rice Roots
Journal name Journal of Environmental Quality   Check publisher's open access policy
ISSN 0047-2425
1537-2537
Publication date 2010-10-27
Year available 2010
Sub-type Article (original research)
DOI 10.2134/jeq2010.0139
Open Access Status
Volume 40
Issue 3
Start page 679
End page 695
Total pages 17
Place of publication Madison, WI United States
Publisher American Society of Agronomy, Inc.
Language eng
Formatted abstract
The speciation and distribution of Co in soils is poorly understood. This study was conducted using x-ray absorption spectroscopy (XAS) techniques to examine the influence of soluble cobalt in the +2 oxidation state (Co[II]) aging, submergence-dried cycling, and the presence of in vivo rice roots on the speciation and distribution of added Co(II) in soils. In the aging and submerged-dried cycling studies, Co was found to be associated with Mn oxide fraction (23 to 100% of total Co) and Fe oxide fractions (0 to 77% of total Co) of the soils as either Co(II) species or a mixed Co(II), and Co in the +3 oxidation state (Co[III]) species. The surface speciation of Co in the Mn oxide fraction suggests an innersphere complex was present and the speciation of Co in the Fe oxide fraction was an innersphere surface complex. The in vivo root box experiments showed similar Co speciation in the Mn oxide fraction (13 to 76% of total Co) as the aging and submergeddried cycling studies. However, the Fe oxide fraction of the soil was unimportant in Co retention. A significant amount (24 to 87% of total Co) of the Co in root box treatments was identified as a Co precipitate. The importance of this finding is that in the presence of rice roots, the Co is redistributed to a Co precipitate. This work confirmed earlier macroscopic work that Mn oxides are important in the sequestration of Co in soils and the influence of roots needs to be taken into account when addressing Co speciation. The information gained from this study will be used to improve models to predict the lability and hence the availability of Co in terrestrial environments.
Keyword In situ
In vivo
Rice roots
Cobalt; Manganese
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Agriculture and Food Sciences
 
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Created: Sat, 01 Feb 2014, 03:16:56 EST by Laura Wendling on behalf of School of Agriculture and Food Sciences