A reactive mat to remediate contaminated sediments and reduce health risks

描述（由申请人提供）： 目前正在开发一种新型的可渗透的活性复合材料，用于污染沉积物的补救和管理。它由一个或多个过滤层组成，过滤层围绕沉积物表面的反应层。流体动力学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、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，geciccomposite如何在长期实地应用中发挥最有效的作用; 2）复合材料如何有效地减少与沉积物结合的污染物有关的生态和人类健康风险。研究的具体目的是解决以下基本问题：1）可以用于复合材料中的反应性材料是什么？这些材料将最有效地降解或转化PCB，多环芳烃（PAH）和金属的目标污染物？2)对于不同的土壤-污染物-孔隙流体化学组合，污染物输送的平流和扩散成分之间的关系是什么？3)如何从模拟沉积物-污染物-复合物系统的实验室规模的实验结果来预测复合物在现场应用中的可扩展性？4)复合物的实际存在以及复合物与污染物的反应对底层沉积物和上层底栖生物有何影响，以支持这些区域健康和多样化的底栖生物群落？5)地质复合材料是否减少了与受污染沉积物有关的人类健康风险？研究将分四个阶段进行：1）对每个超级基金场地的沉积物进行测试，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良剂之间的反应性; 3）利用计算机自动化装置进行台架试验，模拟沉积物-复合物-底栖系统，该装置将沉积物固结和污染物通过沉积物和复合物的迁移结合起来，并评估沉积物固结前后的生物活动，以及上覆“清洁”沉积物中的生物生成;以及4）建立该过程的模型，考虑渗透、固结、分散以及吸附和转化引起的反应。与公共卫生的相关性：受污染的沉积物是一个全球性的公共卫生挑战，需要采取新的创新办法。通过固定和/或中和污染物，该复合材料具有使污染物进一步迁移最小化的潜力，并且在水下环境中，使污染物再悬浮和扩散到上覆水柱中最小化。这将限制污染物在水生食物网中的生物利用度和生物累积性，而水生食物网可能是人类通过摄入接触污染物的途径。

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.