Hydrogeochemische Speziierung von Arsen, Gold und Kupfer in Eisen-Sulfid-Systemen unter Berücksichtigung abiotischer und mikrobiell katalysierter Wechselwirkungen

砷和硫的络合作用对亚缺氧水生环境中的无机砷化学有重要的影响，但到目前为止很少被考虑到，例如在酸性样品保存过程中无定形砷硫相的沉淀，氢化物发生过程中的错误形态识别，以及移动性、氧化还原行为和毒性的变化。拟议的项目将首先改进亚铁-硫化物体系中(硫代)砷物种的保存和分析技术(IC-ICPMS)，这些体系具有世界重要性，因为它们拥有各种具有经济意义的矿体和饮用水含水层。实验室批量和柱实验将显示，在没有金和铜存在的情况下，硫代砷酸盐溶液和表面络合作用对砷在铁(氢)氧化物和铁硫化物上的吸附和再活化的影响。实地研究将包括活跃的地热系统内的成矿过程，矿场的自然风化过程，以及活性铁障内的氧化还原过程。该项目的一个特别重点是在实验室生长实验和自然条件下确定微生物催化与非生物物种转化硫代砷酸盐的重要性和速率，包括各自微生物群落的特征。

Complexation of arsenic and sulfur has a significant - and so far seldom considered - impact on inorganic arsenic chemistry in suboxic aquatic environments, such as precipitation of amorphous arsenic-sulfur phases during acidic sample preservation, erroneous species identification during hydride generation, and changes in mobility, redox behavior, and toxicity. The proposed project will start by improving preservation and analytical techniques (IC-ICPMS) for (thio)arsenic species in ferrous-sulfidic systems which have a worldwide importance since they host various economically interesting ore bodies and drinking water aquifers. Laboratory batch and column experiments will show the effect of thioarsenate solution and surface complexation on arsenic sorption to and remobilisation from iron(hydr)oxides and iron-sulfides in the absence and presence of gold and copper. Field studies will include ore formation processes within active geothermal systems, natural weathering processes at mine sites, and redox processes within reactive iron barriers. A special focus of the project is the determination of importance and rate of microbially catalyzed versus abiotic species transformations of thioarsenates in laboratory growth experiments and under natural conditions including characterization of the respective microbial communities.