Mixed contaminants in soil and groundwater - some fundamental problems and their relevance to remediation and treatment

混合污染物是土壤修复和地下水处理的主要挑战。该提案针对的是迫切需要研究土壤和地下水中混合污染物的影响。拟议的工作将超越单一类别的污染物（例如铅、铜、锌;石油碳氢化合物、溴化或氟化化合物）。目前对这些污染物的认识存在重大差距，包括污染物以混合物形式存在时在土壤中的归宿和迁移，转化机制，特别是在低流动性地区，处理技术之间的潜在协同增效作用，以及混合污染物在羽流中的迁移。我的研究主要集中在了解污染物的命运和运输过程，以帮助改善环境保护和管理实践，以防止污染物的传播，并减少不利的健康和生态风险的目标。 饮用水中的许多全氟烷基和多氟烷基物质（PFAS）与特定来源有关，如工业场所、军事消防训练区和废水处理厂。 必须认识到，几乎所有被全氟辛烷磺酸污染的场地的地下水中都含有一种以上的污染物，通常是混合的羽流，包括石油产品、氯化溶剂和非氯化化合物等燃料成分，例如，在消防培训演习期间同时释放到地下。 尽管两种或多种污染物共同存在，但迄今为止，关于全氟辛烷磺酸在共污染物和共污染物补救方面的归宿和迁移的详细研究在很大程度上缺失。** 拟议的工作将寻求深入了解控制PFAS以及地下水中混合的多环芳烃和1，4-二氧六环影响的基本归宿和迁移过程。我们将特别关注多氟烷基在源区的释放和转化为问题更大的全氟烷基物质，以及通常采用的补救技术的成功程度，这些技术往往是基于单一污染物。近期研究的具体目标是：（1）研究PFASs在复杂土壤介质中的吸附和释放机理，（2）研究PFASs和混合污染物在低渗透性土壤中的扩散和潜在的非生物反应;并确定多环芳烃的影响，1，4-二氧六环和降解副产物对PFASs及其降解产物在一维流通土柱中穿透的影响。 在这些混合污染物系统的基本命运和运输过程中，提高洞察力的最终目标是促进发展和优化的处理策略管理PFAS网站，其中有混合共污染物。

Mixed contaminants pose major challenges in soil remediation and groundwater treatment. This proposal addresses the urgent need to study the effects of mixed contaminants in soil and groundwater. The proposed work will go beyond single classes of contaminants (e.g. lead, copper, zinc; petroleum hydrocarbon, brominated or fluorinated compounds). Significant gaps in current understanding of these contaminants include contaminant fate and transport in soil when present in mixtures, and transformation mechanisms, particularly in low-mobility zones, potential synergies among treatment technologies, and transport of mixed contaminants in plumes.******My research is primarily focused on understanding fate and transport processes of contaminants, to help improve environmental protection and management practice, with the goals of preventing the spread of contaminants, and reducing adverse health and ecological risks. Many of the perfluoroalkyl and polyfluoroalkyl substances (PFASs) in drinking water are linked to specific sources, such as industrial sites, military fire-training areas and wastewater treatment plants. It is important to recognize that almost all PFAS-contaminated sites contain more than one contaminant in groundwater, often in commingled plumes, including fuel components such as petroleum products, chlorinated solvents and non-chlorinated compounds, e.g. simultaneously released to the sub-surface during fire-fighting training exercises. Despite this common co-existence of two or more contaminants, detailed study of the fate and transport of PFASs in relation to co-contaminants and co-contaminant remediation is largely missing to date. ******The proposed work will seek to provide insight into the fundamental fate and transport processes that control the impact of PFAS, as well as comingled polycyclic aromatic hydrocarbons (PAHs) and 1,4-dioxane, in groundwater. We will particularly focus on the release and transformation of polyfluoroalkyl to the more problematic perfluoroalkyl substances in source zones, as well as the degree of success of commonly employed remediation technologies, which tend to be based on single contaminants. The specific short-term objectives are to: (1) investigate the fundamental mechanisms controlling sorption and release of PFASs from complex soil media; (2) examine the diffusion and potential abiotic reactions of PFASs and comingled contaminants in low-permeability soils; and determine the effects of PAHs, 1,4-dioxane and degradation byproducts on breakthrough of PFASs and their degradation products in one-dimensional flow-through soil columns. The ultimate goal of improved insight into the fundamental fate and transport processes in these mixed contaminant systems is to facilitate the development and optimization of treatment strategies for management of PFAS-sites in which there are comingled co-contaminants.