CAREER: Unraveling the Role of Thin Water Films in Controlling Subsurface Transport of Surface-Active Contaminants across Scales

环境中的人造化学物质可以通过土壤流动，污染对日常生活和国家繁荣至关重要的地下水。在地下，许多这样的污染物在固体颗粒的表面和空气与水之间的界面上是活跃的。由于这种表面活性，大量的有毒化学品可以积聚在土壤中空气和水之间的空间，并对基本的地下水造成长期威胁。虽然土壤中的大多数空气-水界面来自土壤-颗粒表面的薄水膜，但表面活性污染物和薄水膜如何相互作用仍然没有很好地理解。研究人员将调查控制这些复杂相互作用的过程，以改进科学家用于预测和评估人造化学品（如全氟烷基和多氟烷基物质，通常称为PFAS）污染风险的工具。这项研究的结果将导致更有效的清理策略，以减少PFAS和类似污染物对人类健康的危害。科学家们将利用这项关于地下水PFAS污染的研究作为一种资源，与高中教师合作，并通过创新的课程工具和培训来支持亚利桑那州的高中学生，提高他们对STEM的兴趣，并增强他们的经验和批判性思维能力。该项目的目标是推进薄膜介导的保留和质量转移过程的渗流区的表面活性污染物的基本理解，并制定一个跨尺度的框架，结合这一新的信息，以改善宏观运输模型。这项研究将结合联合收割机薄膜理论，实验图像表征，和多尺度建模方法。区分薄膜和散装毛细空气-水界面在土壤中的方法将有可能改变水文学家概念化的表面活性污染物在包气带中的运动。PI将与亚利桑那大学的合作扩展亚利桑那水教育项目WET，图森公立学校的STEM教师和教育学院教授合作。项目教育团队将共同开发，测试和正式制定一个完全基于探究的教育计划，该计划涉及构建和使用物理和数字模型的实践经验，以加深理解和解决问题。正式的教育计划将提供给所有高中在亚利桑那州通过现有的基础设施亚利桑那州项目WET由图森水和亚利桑那州水资源部的支持。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查进行评估来支持的搜索.

Human-made chemicals in the environment can flow through soils to contaminate groundwater that is critical to daily life and the Nation’s prosperity. In the ground, many such contaminants are active at surfaces of solid particles and the interfaces between air and water. Because of this surface-activity, significant amounts of toxic chemicals can accumulate in the spaces between air and water in soils and cause long-term threats to essential groundwater. While most of the air–water interfaces in soils are from thin water films on soil-grain surfaces, how the surface-active contaminants and thin water films interact is still not well understood. Researchers will investigate the processes that govern these complex interactions to improve the tools that scientists use to predict and to assess the contamination risks from human-made chemicals such as the perfluoroalkyl and polyfluoroalkyl substances commonly known as PFAS. The results of this research will lead to more effective cleanup strategies to reduce harm to human health from PFAS and similar contaminants. The scientists will use this research on groundwater PFAS contamination as a resource to collaborate with and support high school teachers with innovative curriculum tools, and training to engage Arizona high-school students, advance their interest in STEM, and enhance their experiential and critical thinking skills. The project goals are to advance the fundamental understanding of the thin-film-mediated retention and mass-transfer processes for surface-active contaminants in vadose zones and to develop a cross-scale framework that incorporates this new information to improve macroscopic transport models. The research will combine thin-film theory, experimental image characterization, and multiscale modeling approaches. The methodological approaches to differentiate the thin-film and bulk capillary air–water interfaces in soils will potentially transform how hydrologists conceptualize the movement of surface-active contaminants in vadose zones. The PI will partner with the University of Arizona’s cooperative-extension Arizona Project WET for Water Education, a STEM teacher in a Tucson public school, and a College of Education professor. Together, the project education team will develop, test, and formalize a fully inquiry-based educational program that involves hands-on experiences in building and using physical and digital models for deepening understanding and problem solving. The formalized educational program will be available to all high schools in Arizona via the existing infrastructure of Arizona Project WET supported by Tucson Water and the Arizona Department of Water Resources.This award is co-funded by the Hydrologic Sciences and Environmental Engineering programsThis award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.