A reactive mat to remediate contaminated sediments and reduce health risks

描述(由申请人提供)： 一种新型的渗透性、反应性复合材料正在开发，用于修复和管理受污染的沉积物。它由围绕放置在沉积物表面上的反应层的一个或多个滤层组成。流体动力分散和孔隙流体流动携带污染物通过复合材料。这项研究的广泛和长期目标是全面了解：1)对于沉积物类型、沉积物污染物和孔隙流体环境的不同组合，这种复合材料如何在长期的现场应用中发挥最有效的作用；以及2)这种复合材料如何有效地降低与沉积物结合的污染物相关的生态和人体健康风险。这项研究的具体目的是解决以下基本问题：1)在复合材料中可以使用哪些活性材料来最有效地固定或转化多氯联苯的目标污染物，多环芳烃(PAHs)，和金属？2)各种土壤-污染物-孔隙流体化学组合的污染物运移的平流和扩散成分之间的关系？3)模拟沉积物-污染物-复合系统的小规模实验结果如何用于预测复合材料在野外应用的可扩展性？4)复合材料的物理存在和复合污染物的反应对底层沉积物和上覆底栖生物的影响是什么，就支持这些区域中健康和多样化的海底群落而言？5)地质复合材料是否降低了与受污染沉积物相关的人类健康风险？研究将分四个阶段进行：1)每个超级基金场地待测试沉积物的沉积物特性，包括物理、化学、生物和固结测试；2)批量化学测试，以评估和优化目标污染物与第三阶段测试的复合活性改进剂之间的反应性；3)小试试验，使用结合沉积物固结和污染物通过沉积物和复合材料的污染物传输的计算机自动设备模拟沉积物-复合底栖生物系统，并评估沉积物固结之前和之后的生物活性，以及上覆“干净”沉积物中的生物生成；4)过程模拟，考虑了吸附转化引起的渗流、固结、弥散和反应性。与公共卫生的相关性：受污染的沉积物是一个全球公共卫生挑战，需要新的、创新的方法。通过固定和/或中和污染物，该复合材料有可能最大限度地减少污染物的进一步迁移，并在水下环境中，污染物再悬浮和扩散到上覆水柱中。这将限制污染物的生物可利用性和水生食物网中的生物积累，这可能是人类通过摄取暴露的途径。

DESCRIPTION (provided by applicant): A new type of permeable, reactive composite is being developed for remediation and management of contaminated sediments. It consists of one or more filtering layers surrounding a reactive layer placed on the sediment surface. Hydrodynamic dispersion and pore fluid flow carry contaminants through the composite. The broad, long-term objective of this research is to develop a comprehensive understanding of: 1) how the gecicomposite would function most effectively in long-term field applications for different combinations of sediment types, sediment contaminants and pore fluid environments; and 2) how effectively the composite can reduce ecological and human health risks associated with sediment-bound contaminants. The specific aims of the research are to address the following fundamental issues: 1) What are the reactive materials that can be used in the composite that will most effectively immobilize or transform the target contaminants of PCB's, polyaromatic hydrocarbons (PAHs), and metals? 2) What is the relationship between the advective and diffusive components of contaminant transport for various soil-contaminant-pore fluid chemistry combinations? 3) How can results from bench-scale experiments that model the sediment-contaminant- composite system be used to predict the composite's scalability for field applications? 4) What are the effects of the physical presence of the composite and the composite-contaminant reactions on both the underlying sediment and overlying benthic organisms, in terms of supporting healthy and diverse benthic communities in these zones? 5) Does the geocomposite reduce the human health risks associated with contaminated sediments? The research will be performed in 4 phases: 1) sediment characterization for each Superfund site sediment to be tested, including physical, chemical, biological and consolidation testing; 2) batch chemical testing to assess and optimize reactivity between target contaminants and the composite reactive amendments to be testing in Phase 3; 3) bench scale tests to model the sediment-composite-benthic system using a computer automated device that combines sediment consolidation and contaminant transport through the sediment and composite, and assess the biological activity before and after sediment consolidation, as well as the biogeneration in the overlying 'clean' sediment; and 4) modeling of the process, accounting for seepage, consolidation, dispersion and reactivity due to adsorption and transformation. Relevance to Public Health: Contaminated sediments present a global public health challenge that requires new, innovative approaches. By immobilizing and/or neutralizing contaminants, the composite has the potential to minimize further contaminant migration and, in subaqueous environments, contaminant resuspension and diffusion into the overlying water column. This will limit the bioavailability of contaminants and bioaccumulation in aquatic food webs, which can be a pathway for human exposure via ingestion.