Per- and polyfluoroalkyl substances (PFAS) are used in in numerous consumer products and industrial applications. Not only are PFAS widely used, but they also cover a vast chemical group with thousands of distinct compounds. Because of this, they have become a ubiquitous occurrence in the environment. Several small and large-scale monitoring programs have shown widespread presence of these compounds in air, surface and ground water, and soil media. As awareness of these chemicals continues to increase, concerns due to their persistence and toxicity to environmental and human health also grows. Through their PFAS Strategic Roadmap, USEPA has been prioritizing ongoing work to better understand and eventually reduce the potential exposure and risks caused by these chemicals. USEPA has also included 29 PFAS to be monitored under the fifth Unregulated Contaminant Monitory Rule (UCMR 5) between 2023 and 2025. In addition to monitoring data, reliable modeling tools to evaluate the fate and transport of these chemicals are critical to the development of risk assessment and remediation strategies. To date, limited work has been done to better understand the fate and transport of these complex chemicals in the environment using existing modeling approaches. Rising public interest and increasing regulatory action has made the need for modeling an important next step in advancing the understanding of these persistent chemicals. This work will focus on applying standard modeling approaches to understand the fate and transport of PFAS. Two models, HYDRUS and GeoPEARL, were used to simulate PFAS measured at contaminated sites. Previously, these models were applied to simulate PFOA and PFOS in groundwater at an airport which had been used as firefighter training site, exposing the area to AFFF. This work has been expanded to include sites with other potential PFAS sources such as landfills. Results from modeling were compared with available groundwater monitoring data for these sites. The practical utility of the standard modeling approaches for application to address the PFAS challenges over small and large geographies are discussed.

SETAC North America 2022

Kent, B., Roy, C., Hoogeweg, G., Ritter, A., Vamshi, R. (Waterborne). Evaluating Subsurface Movement of PFAS Compounds Using Both One and Multi-Dimensional Modeling Approaches.