Department of Environmental Engineering Sciences, University of Florida, PO Box 116450, Gainesville, FL 32611-6450, USA.
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.
Chemosphere. 2014 Jul;107:311-318. doi: 10.1016/j.chemosphere.2013.12.075. Epub 2014 Feb 5.
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.
在垃圾填埋场中，特别是那些含有含砷废物和干墙处置（如建筑和拆除（C&D）垃圾填埋场）的垃圾填埋场中，砷的浸出和形态可能会受到高水平硫化物的影响，形成硫代砷阴离子。本研究开发了一种使用离子色谱（IC）和电导检测器的方法，用于评估含硫填埋场环境中硫代砷的形成潜力。在硫代砷合成混合物的 IC 馏分中，确认了一硫代砷酸（H2AsSO3(-)）和二硫代砷酸（H2AsS2O2(-)），这与之前的文献结果一致。然而，在假定的三硫代砷酸（H2AsS3O(-)）和四硫代砷酸（H2AsS4(-)）IC 馏分中观察到 AsSx(-)（x=5-8）表明存在新的砷多硫化物配合物。所有的硫代砷酸阴离子，特别是三硫代砷酸和四硫代砷酸，在暴露于空气中时都不稳定。开发的硫代砷酸盐分析方法得到了验证，并成功地用于分析了几个垃圾填埋场渗滤液样品。在所测试的所有 C&D 垃圾填埋场渗滤液中都检测到了硫代砷酸阴离子，占渗滤液中总砷的 8.5%左右。与亚砷酸盐或砷酸盐相比，硫代砷酸盐在文献中被报道具有较低的氧化铁矿物吸附性。在 C&D 垃圾填埋场渗滤液中存在硫代砷酸盐，这在评估此类环境中砷迁移的影响时带来了新的担忧。
