Sequestration and immobilization of metal and metalloid contaminants in sediments

我们建议对使用活性改良剂作为替代修复技术进行基础研究 沉积物中优先考虑的有害金属和准金属污染物（即As、Hg、Se、Pb、Cu）， 超级基金和其他受污染场地。这些无机污染物特别成问题 因为它们不会降解，所以在低浓度下对人类和生物体构成慢性健康危害。 浓度，它们可以广泛分散，它们可以通过改变环境而重新流动。 条件下，许多可以生物积累。我们的目标是开发一种分子化学 理解元素螯合机制，作为修正剂之间原位反应的结果 和被污染的沉积物。利用污染场地沉积物的实验室实验，我们将 研究污染物螯合反应和改良产品的老化，目的是 优化新的处理方法，以保持或增加其稳定性，因为沉积环境从 氧化还原。我们将采用先进的光谱和显微镜表征，包括 同步加速器X射线方法，以确定污染物元素的形态，隔离机制， 在复杂的沉积物混合物中，在分子到微观尺度上，我们建议的工作 还将评估调整现有工程技术以提供无功功率的可行性 外地系统的修正。 由于目前污染沉积物的修复替代方案很少，因此本研究将填补空白 关于沉积物添加物及其在海洋中被隔离的污染物的长期归宿的基本知识 地下环境，这目前有助于缺乏接受和使用这种方法。 用于环境中无机污染物的隔离和固定的新方法将 通过降低其进入食物链的能力，从而降低其潜力，对公共卫生产生积极影响 生物累积和生物放大作用。

We propose basic research into the use of reactive amendments as an alternative remediation technology for hazardous metal and metalloid contaminants (namely, As, Hg, Se, Pb, Cu) of high priority in sediments at Superfund and other contaminated sites. These inorganic contaminants are particularly problematic because they do not degrade, they pose chronic health hazards to humans and organisms at low concentrations, they can be widely dispersed, they may be remobilized by changing environmental conditions, and many can bioaccumulate. Our approach is aimed at developing a molecular-chemical understanding of element sequestration mechanisms as a result of in situ reaction between the amendment and contaminated sediments. Using laboratory experiments with sediments from contaminated sites, we will nvestigate contaminant sequestration reactions and aging of the amendment products, with the aim of optimizing novel treatments to maintain or increase their stability as sedimentary environments change from oxidized to reduced. We will employ advanced spectroscopic and microscopic characterizations, including synchrotron X-ray methods, to determine contaminant element speciation, mechanism(s) of sequestration, and host phases at the molecular-to-microscopic scale in complex sediment mixtures. Our proposed work will also evaluate the feasibility of adapting existing engineering technologies for the delivery of reactive amendments to field systems. Because few remediation alternatives exist presently for contaminated sediments, this research will fill gaps in basic knowledge about the long-term fate of sediment amendments and their sequestered contaminants in subsurface environments, which presently contributes to a lack of acceptance and use of this approach. New methods for the sequestration and immobilization of inorganic contaminants in the environment will have positive impacts on public health by reducing their ability to enter the food chain and thus their potential bioaccumulation and biomagnification.