Leaching of PFASs from PFAS-Impacted Construction Materials: An Experimental and Modeling Study

The extensive use of aqueous film-forming foam (AFFF) at US military facilities has led to significant contamination of poly- and perfluoroalkyl substances (PFASs) of the subsurface. So far, PFASs contamination at firefighting training areas (FTAs) has been mostly studied in groundwater and soil, neglecting the contribution of leaching from PFASs-contaminated construction materials such as concrete and asphalt into the adjacent environment. Previous studies measured PFASs concentrations reaching up to mg/kg in concrete and asphalt at FTAs and leaching substantial levels (up to μg/L) into runoff water.

Our study investigates the PFASs leaching behavior from AFFF-impacted construction materials, focusing on concrete and asphalt sourced from military sites. The primary objectives include evaluating PFAS leaching rates and duration under various weathered and stabilizer-treated conditions and assessing the effectiveness and potential longevity of reforming techniques and sorbent materials in mitigating PFAS contamination in surface runoff. These data are critical for estimating stormwater treatment lifecycle costs and comparing treatment with other remedial alternatives, such as excavation and disposal. Dynamic rainfall simulations were conducted on intact PFAS-contaminated cores to replicate field conditions. Preliminary results indicate that biochars hold significant potential as sorbents when integrated into concrete formulations, effectively adsorbing PFASs and improving the concrete matrix. Additionally, we hypothesize that rainfall contact time on concrete and asphalt surfaces plays a critical role in influencing PFAS concentrations, a hypothesis which will be tested through both laboratory experiments and modeling efforts. To support this, a funnel prototype was developed to assess the effects of slope and contact time on PFAS leaching profiles. These findings provide important insights into PFAS leachability under varying conditions and highlight the environmental implications of reusing PFAS-impacted construction materials across various industries, including PFAS manufacturing and chrome plating.

The results underscore the critical need for additional leaching experiments to advance sustainable reuse practices for PFAS-impacted construction materials. Such efforts are essential for developing cost-effective source control strategies and lifecycle comparisons to inform broader remediation frameworks in both military and industrial applications.

 

Keywords: PFASs-impacted construction materials, Leaching behavior, Dynamic rainfall simulation, Concrete and asphalt reuse, Sorbent materials.