Abstract
The widespread use of aqueous film-forming foams (AFFFs) in firefighting has led to significant contamination by per- and polyfluoroalkyl substances (PFAS), including in building materials like concrete. This study investigated the initial phase of PFAS contamination in concrete, focusing on factors influencing PFAS retention and penetration. Laboratory experiments assessed the uptake kinetics of PFAS into concrete over one year, revealing that PFAS penetrated beyond surface layers, as confirmed by high-resolution mass spectrometry and desorption electrospray ionization mass spectrometry imaging. PFAS mass loss into the concrete was limited, with 0.99% to 18.5% (mean 6.6%) of initial spiked PFAS being retained. Uptake behaviors were influenced by PFAS chain length and chemistry, concrete surface characteristics, as well as wetting/drying cycles, which accelerated PFAS penetration through the wick effect. Damaged concrete surfaces also showed faster PFAS penetration due to the exposed interfacial transition zones. Field-impacted concrete samples from Canada revealed some similar migration trends with lab-exposed concrete, with shorter-chain PFAS exhibiting greater mobility in the concrete matrix, though notable differences were observed between field and lab samples. These findings highlight the complex dynamics of PFAS contamination in concrete and provide insights into factors affecting PFAS penetration and retention.