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Title: Formation of soluble mercury oxide coatings: Transformation of elemental mercury in soils

In this study, the impact of mercury (Hg) on human and ecological health has been known for decades. Although a treaty signed in 2013 by 147 nations regulates future large-scale mercury emissions, legacy Hg contamination exists worldwide and small-scale releases will continue. The fate of elemental mercury, Hg(0), lost to the subsurface and its potential chemical transformation that can lead to changes in speciation and mobility are poorly understood. Here, we show that Hg(0) beads interact with soil or manganese oxide solids and X-ray spectroscopic analysis indicates that the soluble mercury coatings are HgO. Dissolution studies show that, after reacting with a composite soil, >20 times more Hg is released into water from the coated beads than from a pure liquid mercury bead. An even larger, >700 times, release occurs from coated Hg(0) beads that have been reacted with manganese oxide, suggesting that manganese oxides are involved in the transformation of the Hg(0) beads and creation of the soluble mercury coatings. Although the coatings may inhibit Hg(0) evaporation, the high solubility of the coatings can enhance Hg(II) migration away from the Hg(0)-spill site and result in potential changes in mercury speciation in the soil and increased mercury mobility.
 [1] ;  [2] ;  [2] ;  [3] ;  [4] ;  [5] ;  [2] ;  [2]
  1. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Troy Univ., Troy, AL (United States)
  2. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
  3. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Hitachi High Technologies Canada, Inc., Toronto, ON (Canada)
  4. Queen's Univ. Belfast, Belfast (United Kingdom)
  5. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Zhejiang Univ. of Technology, Zhejiang (People's Republic of China)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Environmental Science and Technology
Additional Journal Information:
Journal Volume: 49; Journal Issue: 20; Journal ID: ISSN 0013-936X
American Chemical Society (ACS)
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Environmental Management (EM)
Country of Publication:
United States
OSTI Identifier: