Interactions between microplastics and per- and polyfluoroalkyl substances (PFAS)

Full title: Interactions between microplastics and per- and polyfluoroalkyl substances (PFAS): Implications in terrestrial environments

Presented lightning talk on April 28, 2022, by Jenny Zenobio - Jacobs - at the 2022 Emerging Contaminants in the Environment Conference (ECEC22)

Microplastics (MPs) possess high sorption affinities for hydrophobic organic contaminants, which may alter the fate, transport, and bioavailability of both MPs and the adsorbed compounds in natural systems. Per- and polyfluoroalkyl substances (PFAS) are widely used chemicals due to their hydro/-oleo-phobicity; and as a result, are ubiquitous in the environment. Adsorption of PFAS by MPs and the environmental implication of the adsorption is not well understood. In this study, the interactions of six commonly detected PFAS [perfluorobutane sulfonate, PFBS; perfluorooctane sulfonate, PFOS; perfluorooctane sulfonamide, FOSA; perfluorobutanoic acid, PFBA; hexafluoropropylene oxide dimer acid, GenX; and perfluorooctanoic acid, PFOA] with five microplastics [polypropylene, PP; low-density polyethylene, PE; polystyrene, PS; polyvinyl chloride, PVC; and polytetrafluoroethylene, PTFE] were investigated. In addition, the impact of MPs on bioaccumulation of PFAS in soil by earthworm (Eisenia fetida) was investigated. Compared to perfluorocarboxylic acids [such as PFOA and PFBA], perfluorosulfonic acids [such as PFOS and PFBS] adsorbed more to MPs. The amount of PFAS adsorbed increased with increasing chain-length for both carboxylic acids and sulfonic acids. FOSA was the most adsorbed PFAS to all the MPs, with PTFE having the highest adsorption capacity of 104.74 μg/g for FOSA. Higher bioaccumulation of PFAS by earthworms was observed when PFAS were mixed with MPs before application to soil. Our results suggest microplastics act as chemical vectors delivering PFAS into earthworms and contributing to PFAS accumulation.