Field-scale evidence of PFAS pollution potential from municipal landfills

Leachate from municipal landfills is a major source of per- and polyfluoroalkyl substances (PFAS) to groundwater. This study presents field-scale evidence of PFAS generation, release, and downward migration in a closed landfill comprising a 15 m waste body overlying a 16 m sandy unsaturated zone. PFAS composition and transport were monitored using a vadose zone monitoring system, with monthly leachate and porewater sampling over six months (November 2022–April 2023). Analysis of leachate samples shows short-chain perfluoroalkyl carboxylic acids (PFCAs), particularly PFBA, PFPeA, and PFHxA, dominate leachate and are preferentially released from decomposing waste, subsequently migrating through the unsaturated zone. In contrast, long-chain PFAS (PFOS, PFNA) and the precursor 6:2 FTS persist in shallow waste (