Assessment and remdiation of As enrichments in groundwater

天然或人工富集砷的地下水在世界许多地方（包括美国）构成严重的健康危害。该项目的基础上，越来越多的认识到，特别是高亲和力的Fe-羟基氧化物作为调节溶解在地下水中的砷浓度的一个关键因素。铁羟基氧化物的特殊亲和力已被开发的建议值为10 μ g/L，在不久的将来，一个更好的基本了解不同的治疗方案和地下水成分对治疗效果的影响是必要的。（I）As动员到减少地下水中：来自ME的温斯洛普和NH的Vineland（项目）和孟加拉国（项目5）的美国超级基金现场的现场材料将用于量化在氧化和还原条件下溶解相和特定相之间的As交换。在第一组实验中，潜在的综合还原溶解释放的As将确定与羟胺提取归档含水层材料覆盖范围内的氧化还原条件。还原溶解释放的As和FE的空间格局将比较含水层中的氧分布。在第二组实验中，将培养选定地点的含水层新鲜岩心，以量化As和Fe交换（吸附或解吸）的速率。在第三组实验中，国家的最先进的表面分析技术将被用来表征砷结合在模型铁氧化物表面的一系列条件下的自然环境的代表。主题（二）还原性地下水中砷的去除：氯化铁共沉淀法是一种常用的去除水中砷的有效技术。从地下水中去除砷的另一种方法是有希望的，但尚未得到充分评价，这依赖于Fe屑的吸附性能。这种方法被认为是非常有效的，但尚未得到充分的评价依赖于铁屑的吸附性能。发现该方法在温斯洛普，ME，超级基金中心非常有效，并将在新泽西州葡萄园的另一个中心进行测试。Fe屑去除As的机制也将使用表面光谱进行探讨。这一主题下的另一个目标是制定减少砷补救规模的实用方法，从而满足美国和孟加拉国国内威尔斯用户的需求。我们将尽可能利用地下水中的天然铁含量，专注于氢氧化铁基处理。将与当地政府研究人员合作探索孟加拉国现有除铁装置的除砷潜力。还将研究美国和孟加拉国的锉作为共沉淀法处理家用电池水的铁替代来源的潜力。

Groundwater naturally or anthropogenically enriched in As poses serious health hazards in many parts of the world, including the US. This project builds on the growing realization that the particular high affinity of As for Fe-oxyhydroxides is a key factor regulating dissolved As concentrations in groundwater. The particular affinity of As for Fe-oxyhydroxides has been exploited for recommended value to 10 mug/L in the near future, a better fundamental understanding of different treatment options and the influence of groundwater composition on the efficacy of treatment is needed. Them (I) As mobilization into reducing groundwater: Field material from US Superfund sites at Winthrop, ME and Vineland, NH (Project) and Bangladesh (PROJECT 5) will be used to quantify the exchange of As between the dissolved and the particular phase under oxic and reducing conditions. In a first set of experiments, the potential integrated release of As by reductive dissolution will be determined with hydroxylamine extraction from archived aquifer material covering a range of redox conditions. The spatial patterns of As and FE released by reductive dissolution will be compared to the oxygen distribution in the aquifers. In a second set of experiments, fresh cores of aquifer from selected sites will be incubated to quantify the rate of As and Fe exchange (adsorption or desorption). In a third set of experiments, state-of-the-art surface analytical techniques will be used to characterize arsenic binding at model Fe oxide surfaces under a range of conditions representative of the natural environment. Theme (II) As removal from reducing groundwater: Co-precipitation treatment with ferric chloride is an effective technique commonly used for the removal of arsenic form water. A different approach for removing As from groundwater that is promising but has not yet been fully evaluated relies on the adsorptive properties of Fe filings. This method was found to be very effective but has not yet been fully evaluated relies on the adsorptive properties of Fe filings. This methods was found to be very effective at the Winthrop, ME, Superfund site and will be tested at another site in Vineland, NJ. The mechanisms of As removal by Fe filings will also be probed using surface spectroscopy. Another objective under this theme is to develop practical ways of reducing the scale of As remediation and hereby meet the needs of users of domestic wells in the US and Bangladesh. We will focus on Fe-oxyhydroxide-based treatment using, whenever possible, the natural Fe content of groundwater. The As- removal potential of existing Iron Removal Units in Bangladesh will be explored in collaboration with local government researchers. The potential of filings as an alternative source of Fe for co-precipitation to treat water from domestic cells in the US and Bangladesh will also be examined.