Collaborative Research: In Situ Laboratory Imaging and Modeling of PFAS Transport and Fate in Variably Saturated Heterogeneous Porous Media

目前保留在地下水位以上浅层地下的全氟烷基和多氟烷基物质的浸出是地下水污染的一个持久来源。这种滞留过程非常复杂，因为PFAS在浅层地下迁移的时间和程度受土壤性质、气候和天气事件以及特定地点的水文地质条件的控制。尽管在了解PFAS的迁移和滞留行为方面取得了重大进展，但对于地质性质的空间变化（对地下水流动过程有强烈影响）如何影响PFAS污染在地下迁移的方式、时间和地点，仍然存在关键的知识空白。该研究提高了在更现实的地质条件下测量和模拟PFAS迁移和保留的能力。为不同背景的学生研究人员提供培训，并开展外联活动，使处理PFAS污染问题的水专业人员参与其中。提高对PFAS在地下迁移的理解将使PFAS修复策略的发展取得进展。本项目利用医学成像技术和最新的数值模型来量化PFAS在非均质非饱和地质多孔介质中的动态、空间变量吸附。具体目的是测量两种代表性PFAS在饱和和部分饱和非均相柱中的原位吸附。这些延时成像测量结果可用于直接验证先进的空间分辨率数值模型，并能够开发非均匀地下条件下PFAS传输的规模化模型。这项工作提供了前所未有的原位迁移和吸附测量，升级方法，以及用于描述和预测PFAS通过土壤到地下水含水层的数值模型的参数化。本项目由GEO/EAR水文科学（1579）项目和ENG/CBET环境工程（1440）项目共同资助。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Leaching of per- and polyfluoroalkyl substances (PFAS) currently retained in the shallow subsurface above the water table is a persistent source of groundwater contamination. This retention process is very complex because the timing and extent of PFAS mobility in the shallow subsurface are controlled by soil properties, climate, and weather events, and site-specific hydrogeologic conditions. Despite significant advances in understanding the migration and retention behavior of PFAS, there remains a critical knowledge gap on how spatial variation in geologic properties—which have a strong impact on groundwater flow processes—impact how, when, and where PFAS contamination migrates in the subsurface. This research advances the ability to measure and model PFAS migration and retention under more realistic geologic conditions. Training is provided to student researchers of diverse backgrounds, and outreach is conducted to engage with water professionals dealing with PFAS pollution problems. Improved understanding of PFAS migration in the subsurface will enable future progress in PFAS remediation strategy development.This project uses medical imaging technology and recent advances in numerical models to quantify dynamic, spatially variable PFAS adsorption in heterogeneous unsaturated geologic porous media. The specific aims are to measure in situ adsorption of two representative PFAS in saturated and partially saturated heterogeneous columns. These time-lapse imaging measurements are used, in turn, to provide direct validation to advanced spatially-resolved numerical models and enable the development of upscaled models of PFAS transport under heterogeneous subsurface conditions. This work offers unprecedented in situ transport and adsorption measurements, upscaling approaches, and parameterization of a numerical model used to describe and predict PFAS leaching through soils to groundwater aquifers.This project is jointly funded by the GEO/EAR Hydrologic Sciences (1579) Program and the ENG/CBET Environmental Engineering (1440) program.This 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.