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Abstracts

“Development and Validation of Sealants to Mitigate Leaching and Mobility of PFAS in Concrete” by Dr. Divina Navarro (ER23-3638) 

Concrete infrastructure at DoW sites with historical AFFF use can act as an ongoing PFAS source due to infiltration and transport through pore networks and cracks. Removal and replacement are often costly and operationally disruptive, creating a need for practical in-place mitigation strategies. Sealants and surface treatments are emerging as a promising approach to reduce PFAS leaching from contaminated concrete. However, comparative performance data and structured selection guidance remain limited. This webinar presents a decision-support framework that integrates multiple criteria for evaluating and down-selecting sealant technologies for PFAS mitigation. No single sealant type meets all operational requirements, underscoring the importance of a structured, site-specific, criteria-based selection approach for DoW infrastructure PFAS risk mitigation. 

“Assessment for Leachability of PFAS from Concrete/Asphalt Paved Surfaces, Stockpiles, and Beneficial Reuse Scenarios: Laboratory and Bench Studies” by Dr. Timothy Townsend (ER23-3835) 

Pavement materials are often recycled at the end of their useful life; however, the presence of PFAS on pavements exposed to AFFF at DoW sites may complicate or nullify traditional management practices. The DoW requires information regarding the management of PFAS-impacted pavement materials, balancing costs, feasibility, and efficacy for PFAS treatment. This project aims to enhance understanding of PFAS leaching from pavement materials during a variety of disposal and reuse scenarios. Methods include a combination of well-established leaching tests and state-of-the-art PFAS analysis to provide key information regarding the fate and transport of PFAS from AFFF-impacted paved surfaces and pavement debris. Project outcomes shall inform a framework for management of AFFF-impacted pavement materials. 

Speaker Biographies

Dr. Divina Navarro is a Senior Research Scientist with Australia’s national science agency, CSIRO. She is an environmental analytical chemist with more than 15 years of experience investigating the fate, transport, and management of chemicals of concern, with a particular focus on PFAS in soils and infrastructure materials. Dr. Navarro leads multidisciplinary research that translates environmental analytical science into practical management strategies for impacted sites. She has contributed to multiple SERDP projects examining PFAS leaching and mobility in impacted materials and currently leads a project investigating the use of surface and penetrating sealants to reduce PFAS migration from concrete. Dr. Navarro received her bachelor’s degree in chemistry at the University of the Philippines and her doctoral degree in chemistry at the University at Buffalo. 

Dr. Timothy Townsend is the Distinguished Professor of Environmental Engineering Sciences in the University of Florida’s Engineering School of Sustainable Infrastructure and Environment.  He is also the executive director of the Hinkley Center for Solid and Hazardous Waste Management. He teaches and conducts research in the discipline of  materials management. Courses developed and instructed by Dr. Townsend include solid and hazardous waste management; beneficial use of solid wastes; construction and demolition debris management; and the science, economics, and policy of recycling. Dr. Townsend is well published in the scientific literature regarding waste management and is best known for his research related to electronic wastes, bioreactor landfills, construction and demolition debris, waste beneficial use, and recycling of waste-to-energy ash. He received his bachelor’s, master’s of engineering, and doctoral degrees in environmental engineering at the University of Florida.