Arsenic-sulfur speciation - a potential key to understanding arsenic accumulation and mobilisation in sulfidic aquifers of Bangladesh

砷-硫形态——了解孟加拉国含硫含水层中砷积累和迁移的潜在关键

• 批准号: 25229056
• 负责人: Professorin Dr. Britta Planer-Friedrich
• 金额: --
• 依托单位: Lehrstuhl für Umweltgeochemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2006
• 资助国家: 德国
• 起止时间: 2005-12-31 至 2009-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/25229056?language=en
• 关键词: Arsenic; sulfur; speciation; potential; key

Bangladesh is currently the country believed to show the largest impact of arsenic poisoning worldwide from drinking water. Screening on total arsenic concentrations and householdbased remediation measures have been implemented over the past 10 years, but the origin of the arsenic is still not clear. During the proposed project we will screen wells of different depths tapping different geological formations with major focus on pH, redox potential, redox sensitive species, and stable isotopes. Sediment samples in column experiments will be exposed to O2, CO2, phosphate, humic acids, and respiratory inhibitors to illuminate different mechanisms of arsenic mobilization. Continuous sampling of monitoring wells of different depths will show depth and time dependent variations in chemistry. Contrary to all other studies conducted before, arsenic speciation beyond inorganic As(lll)/As(V) speciation will be done. The importance of methylated arsenic species in organic-rich strata and the potential of arsenic-sulfur species formation on the mobilization of arsenic from ironsulfides will be investigated. Arsenic-sulfur species have seldom been investigated so far but can be an important clue in arsenic chemistry in sulfidic waters. Modeling will help to better understand the situation in Bangladesh and predict similar scenarios in other countries worldwide.

据信，孟加拉国目前是全球饮用水砷中毒影响最大的国家。在过去10年中，对总砷浓度进行了筛查并采取了以家庭为基础的补救措施，但砷的来源仍然不清楚。在拟议项目期间，我们将筛选不同深度的威尔斯井，挖掘不同的地质构造，主要关注pH值、氧化还原电位、氧化还原敏感物质和稳定同位素。柱实验中的沉积物样品将暴露于O2，CO2，磷酸盐，腐殖酸和呼吸抑制剂，以阐明砷动员的不同机制。对不同深度的监测威尔斯井进行连续取样，将显示化学性质随深度和时间的变化。与之前进行的所有其他研究相反，将进行无机As（III）/As（V）形态之外的砷形态。甲基化砷物种在有机富集地层中的重要性和砷硫物种形成对铁硫化物中砷的活化的潜力将被研究。砷-硫物种很少被研究，但可以在硫化物沃茨中的砷化学的一个重要线索。建模将有助于更好地了解孟加拉国的情况，并预测世界其他国家的类似情况。