Climate-driven per- and polyfluoroalkyl substances transfer via Drosophila from landfills in China: A hidden biological vector under global warming

Drosophila, as saprophagous and highly mobile insects, may serve as emerging biological vectors for per- and polyfluoroalkyl substances (PFASs) in landfill environments. This study quantified the bioconcentration potential of PFASs in Drosophila under both leachate and standard PFASs exposures across life stages, exploring the effects of physicochemical properties of PFASs on bioconcentration. A feature-based model integrating temperature and humidity was developed to simulate bioconcentration factors (BCFs), which were used to estimate PFAS transfer fluxes across national landfill sites under various Shared Socioeconomic Pathways (SSP, SSP1-1.9 to SSP5-8.5). Results revealed that PFAS bioconcentration in Drosophila was governed by both chemical properties (e.g., chain length, polarity) and climatic factors, with BCFs showing non-linear inverted U-shaped responses to temperature and humidity. Climate-driven simulations demonstrated that national PFAS transfer via Drosophila will increase significantly under warming scenarios in Chinese landfills, especially for emerging compounds such as hexafluoropropylene oxide dimer acid (GenX) and 6:2 fluorotelomer sulfonate (6:2 FTS). Although the current estimated PFAS transfer via Drosophila (1.49 kg yr-1) is lower than leachate discharge, its persistence, cross-media mobility, and biological amplification underscore its environmental significance. This study provides the first climate-sensitive framework for evaluating PFAS migration mediated by insects and highlights the need to incorporate biological vectors into PFAS risk assessments.