Advances and Research Gaps for PFAS Modeling in Watersheds and Receiving Waters

Abstract Submission: The research on various aspects of PFAS has been active and evolving. Originally viewed as mainly a drinking water challenge, “PFAS is everywhere” has made its concerns extended into other water matrices such as wastewater, stormwater, recycled water, and groundwater. Given the complex nature of PFAS including its persistence across the entire water cycle and a general lack of monitoring data on background levels from different potential sources, it has been challenging for watershed models to explicitly simulate PFAS fate and transport processes in order to better support water quality-based management decisions and pollution control strategies. ASCE Manual of Practice 150 published in 2022 focused on the state-of-the-practice for more traditional pollutants of concern in watershed and water quality modeling such as nutrients and sediments. This is one of the knowledge gaps identified for watershed and water quality modeling in the Manual of Practice 150. Therefore, the objective of this paper is to synthesize the advancements and research gasps in PFAS modeling in the context of holistic watershed management and make recommendations for future research. Through an initial effort, it is found that many process formulations for PFAS modeling are still empirical in nature and need additional rigorous evaluations for real-world modeling applications. Further research on mechanistic approaches based on more in-depth understanding of PFAS-soil-water-plant interactions are needed, which will make numerical model parameters are less site-dependent and more predictive in simulating PFAS fate and transport at a watershed scale to better support holistic watershed management.

Learning Objectives/Expected Outcome (Optional) : (1) To learn the current practice of PFAS modeling in watersheds and receiving water.
(2) To learn the identified research gaps on PFAS modeling and future recommendations.
(3) To learn the connection between PFAS modeling and ASCE Manual of Practice 150 on “TMDL Development and Implementation: Models, Methods, and Resources.”