title: Methodology for assessing thioarsenic formation potential in sulfidic landfill environments.
abstract: Arsenic leaching and speciation in landfills, especially those with arsenic bearing waste and drywall disposal (such as construction and demolition (C&D) debris landfills), may be affected by high levels of sulfide through the formation of thioarsenic anions. A methodology using ion chromatography (IC) with a conductivity detector was developed for the assessment of thioarsenic formation potential in sulfidic landfill environments. Monothioarsenate (H2AsSO3(-)) and dithioarsenate (H2AsS2O2(-)) were confirmed in the IC fractions of thioarsenate synthesis mixture, consistent with previous literature results. However, the observation of AsSx(-) (x=5-8) in the supposed trithioarsenate (H2AsS3O(-)) and tetrathioarsenate (H2AsS4(-)) IC fractions suggested the presence of new arsenic polysulfide complexes. All thioarsenate anions, particularly trithioarsenate and tetrathioarsenate, were unstable upon air exposure. The method developed for thioarsenate analysis was validated and successfully used to analyze several landfill leachate samples. Thioarsenate anions were detected in the leachate of all of the C&D debris landfills tested, which accounted for approximately 8.5% of the total aqueous As in the leachate. Compared to arsenite or arsenate, thioarsenates have been reported in literature to have lower adsorption on iron oxide minerals. The presence of thioarsenates in C&D debris landfill leachate poses new concerns when evaluating the impact of arsenic mobilization in such environments.
authors: Department of Environmental Engineering Sciences, University of Florida, PO Box 116450, Gainesville, FL 32611-6450, USA.
authors: Jianye
authors: J
authors: Zhang
authors: Department of Environmental Engineering Sciences, University of Florida, PO Box 116450, Gainesville, FL 32611-6450, USA; Department of Environmental Science and Engineering, Gannon University, 109 University Square, Erie, PA 16541-0001, USA.
authors: Hwidong
authors: H
authors: Kim
authors: Department of Environmental Engineering Sciences, University of Florida, PO Box 116450, Gainesville, FL 32611-6450, USA. Electronic address: ttown@ufl.edu.
authors: Timothy
authors: T
authors: Townsend
mesh_terms: D001151:Arsenic / Q000032:analysis / Q000737:chemistry*; D003252:Construction Materials; D007700:Kinetics; D013455:Sulfur / Q000737:chemistry*; D064091:Waste Disposal Facilities; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D014874:Water Pollutants, Chemical; D013455:Sulfur; D001151:Arsenic
keywords: Arsenic; Drywall; Landfill leachate; Sulfide; Thioarsenic