Sequestration and immobilization of metal and metalloid contaminants in sediments

我们建议对反应性修正作为替代补救技术的使用进行基础研究 对于沉积物中高度优先的有害金属和类金属污染物(即As、Hg、Se、Pb、Cu)，在 超级基金和其他受污染的地点。这些无机污染物尤其成问题。 由于它们不会降解，它们对人类和生物体构成了长期的健康危害。 浓度，它们可以广泛分散，它们可能会因环境变化而重新动员 条件，许多可以在生物上积累。我们的方法旨在开发一种分子化学物质 理解元素封存机理作为修饰物之间原位反应的结果 和受污染的沉积物。通过对污染场地的沉积物进行实验室实验，我们将 调查污染物隔离反应和修正产品的老化，目的是 随着沉积环境的变化，优化新的处理方法以保持或增加其稳定性 氧化为还原。我们将采用先进的光谱和显微表征技术，包括 同步辐射X射线法，确定污染物元素形态，隔离机理(S)， 以及复杂沉积物混合物中分子到微观尺度上的主体相。我们建议的工作 还将评估采用现有工程技术交付反应性燃料的可行性 对田野系统的修正。 由于目前对受污染的沉积物几乎没有修复方法，这项研究将填补空白。 关于底泥改良剂的长期命运及其在 地下环境，这导致目前缺乏对这一方法的接受和使用。 环境中无机污染物的隔离和固定的新方法将 通过降低他们进入食物链的能力从而降低他们的潜力，从而对公众健康产生积极影响 生物积累和生物放大作用。

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.