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

目前滞留在地下水位以上浅层地下的全氟烷基物质和多氟烷基物质(全氟烷基物质)的淋溶是地下水污染的持久来源。这一保留过程非常复杂，因为浅层地下PFAS迁移的时间和程度受土壤特性、气候和天气事件以及场地特定水文地质条件的控制。尽管在理解全氟辛烷磺酸的迁移和保留行为方面取得了重大进展，但关于对地下水流动过程有重大影响的地质特性的空间差异如何影响全氟辛烷磺酸污染物在地下迁移的方式、时间和地点，仍然存在严重的知识差距。这项研究提高了在更现实的地质条件下测量和模拟全氟辛烷磺酸迁移和保留的能力。向不同背景的学生研究人员提供培训，并开展外联活动，与处理全氟辛烷磺酸污染问题的水专业人员接触。该项目利用医学成像技术和数值模型的最新进展来量化非均质非饱和地质多孔介质中动态的、空间可变的PFAS吸附。具体目的是测量两种具有代表性的全氟辛烷磺酸在饱和和部分饱和多相柱中的原位吸附。这些延时成像测量反过来用于直接验证先进的空间分辨数值模型，并使在非均匀地下条件下的全氟辛烷磺酸传输的放大模型得以开发。这项工作提供了前所未有的现场传输和吸附测量、放大方法和用于描述和预测PFAS通过土壤淋溶到地下水含水层的数值模型的参数化。该项目由GEO/EAR水文科学(1579)计划和ENG/CBET环境工程(1440)计划联合资助。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.