title: The effects of a stannous chloride-based water treatment system in a mercury contaminated stream.
abstract: We assessed the impacts of an innovative Hg water treatment system on a small, industrially-contaminated stream in the southeastern United States. The treatment system, installed in 2007, removes Hg from wastewater 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 the Tims Branch watershed is not contributing to methylmercury (MeHg) production or bioaccumulation in this system. The stannous chloride treatment system installed at Tims Branch was effective at removing Hg inputs and reducing Hg bioaccumulation in the stream, but future studies are needed to assess longer term impacts of Sn on the environment.
authors.affiliation: Oak Ridge National Laboratory, Oak Ridge, TN 37830, United States. Electronic address: mathewstj@ornl.gov.
authors.forename: Teresa J
authors.initials: TJ
authors.lastname: Mathews
authors.affiliation: Savannah River National Laboratory, Aiken, SC 29808, United States.
authors.forename: Brian B
authors.initials: BB
authors.lastname: Looney
authors.affiliation: Savannah River Ecology Laboratory, Aiken, SC 29808, United States.
authors.forename: A Lawrence
authors.initials: AL
authors.lastname: Bryan
authors.affiliation: Oak Ridge National Laboratory, Oak Ridge, TN 37830, United States.
authors.forename: John G
authors.initials: JG
authors.lastname: Smith
authors.affiliation: Oak Ridge National Laboratory, Oak Ridge, TN 37830, United States; Troy University, Troy, AL 36082, United States.
authors.forename: Carrie L
authors.initials: CL
authors.lastname: Miller
authors.affiliation: Oak Ridge National Laboratory, Oak Ridge, TN 37830, United States.
authors.forename: George R
authors.initials: GR
authors.lastname: Southworth
authors.affiliation: Oak Ridge National Laboratory, Oak Ridge, TN 37830, United States.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Peterson
mesh_terms: D000818:Animals; D005399:Fishes / Q000378:metabolism; D005618:Fresh Water / Q000737:chemistry*; D019015:Geologic Sediments; D006801:Humans; D008628:Mercury / Q000032:analysis* / Q000493:pharmacokinetics; D008767:Methylmercury Compounds / Q000032:analysis / Q000493:pharmacokinetics; D017971:Tin Compounds / Q000737:chemistry*; D014481:United States; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000493:pharmacokinetics; D018508:Water Purification / Q000379:methods*
chemical_list: D008767:Methylmercury Compounds; D017971:Tin Compounds; D014874:Water Pollutants, Chemical; C023599:stannous chloride; D008628:Mercury
keywords: Bioaccumulation; Mercury; Remediation; Stannous chloride; Tin