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Title: The effects of a stannous chloride-based water treatment system in a mercury contaminated stream

Remediation of mercury (Hg)-contaminated watersheds is often challenging because of the complex nature of Hg biogeochemistry. Stream ecosystems have been shown to be particularly susceptible to Hg contamination and bioaccumulation in fish. Decreasing total Hg loading to stream systems, however, has shown variable performance in decreasing Hg concentrations in fish tissues. In this study, we assess the impacts of an innovative treatment system in reducing releases of Hg to a small stream system in the southeastern United States. The treatment system, installed in 2007, removes Hg from water using tin (Sn) (II) chloride followed by air stripping. Mercury concentrations in the receiving stream, Tims Branch, decreased from > 100 to ~10 ng/L in the four years following treatment, and Hg body burdens in redfin pickerel (Esox americanus) decreased by 70 % at the most contaminated site. Tin concentrations in water and fish increased significantly in the tributary leading to Tims Branch, but concentrations remain below levels of concern for human health or ecological risks. While other studies have shown that Sn may be environmentally methylated and methyltin can transfer its methyl group to Hg, results from our field studies and sediment incubation experiments suggest that the added Sn to themore » Tims Branch watershed is not contributing to MeHg production and bioaccumulation. The stannous chloride treatment system installed at Tims Branch was effective at removing Hg inputs and reducing Hg bioaccumulation in the stream with minimal impacts on the environment due to the increased Sn in the system.« less
Authors:
 [1] ;  [2] ;  [1] ;  [3] ;  [1] ;  [4] ;  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Troy Univ., Troy, AL (United States)
  4. Savannah River Site (SRS), Aiken, SC (United States). Savannah River Ecology Lab. (SREL)
Publication Date:
OSTI Identifier:
1185420
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Chemosphere
Additional Journal Information:
Journal Volume: 138; Journal ID: ISSN 0045-6535
Publisher:
Elsevier
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Environmental Management (EM)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY mercury; remediation; stannous chloride; tin; bioaccumulation; fish