The persistence, fate, and transport of per- and poly-fluoroalkyl substances (PFASs), which have been shown to have adverse effects on human health, have been widely studied in environmental media such as soils and groundwater. This study investigates concrete, a medium that is rarely studied but frequently present in instances where PFASs originating from aqueous film forming foam (AFFF) releases and spills have occurred. Used heavily throughout aviation firefighting, AFFF poses environmental hazards due to long PFAS degradation timelines. From the very limited reports to date, studies have suggested very slow release from concrete, potentially serving as a long-term source, prolonging its environmental persistence. This presentation discusses the development of a fate and transport model that can be applied specifically to the concrete in stormwater channels that may drain from AFFF release points. This study consisted of four phases: (1) saturation and contamination, (2) desorption and flushing, (3) sampling and analysis, and (4) the investigation of sealants to mitigate PFAS release. The study used AFFF to investigate retention of PFAS by the concrete, as well as a dye to trace the hydraulics of the flowing water through small mock channels and its permeation in the concrete. A desorption model developed from this data incorporates properties of the concrete and simulated hydrological runoff, along with mechanistic terms for both diffusion and adsorption kinetics. This model can be used to estimate the length of time PFAS may remain above a given action level. Sealing the previously contaminated channels with high performance concrete sealants is investigated as a means to mitigate PFAS release. This is accomplished by repeating the desorption and flushing experiments to determine the correlation between the original flushing samples and the post-sealant samples. Ultimately, this study can provide a model that can be easily adapted to DoD and civilian installations, and it will show the relevance in using concrete sealants to better manage and mitigate PFAS until more permanent measures can be implemented.

Persistence and mitigation of PFASs within concrete of stormwater drainage infrastructure

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.