The hidden cost of green food packaging: Biodegradable plastics release more micro/nanoplastics and enhance PFAS co-exposure.

The global transition toward biodegradable food contact materials (FCMs) aims to mitigate plastic pollution, yet their safety under realistic food service conditions remains underexplored. This study systematically assessed the release of microplastics (MPs) and nanoplastics (NPs) from biodegradable (PLA, PBS, PBAT) versus conventional (PP, PE) FCMs under simulated takeout scenarios. Results demonstrated that biodegradable FCMs released significantly higher particle loads-approximately 10-fold more MPs and 2-fold more NPs-than their conventional counterparts. This release was notably exacerbated in alcoholic and acidic environments, likely owing to the hydrolytic susceptibility of ester bonds in the biodegradable matrices. Additionally, we evaluated the role of these particles as carriers for co-occurring contaminants, particularly perfluorooctanesulfonic acid (PFOS), a persistent contaminant of growing health concern. Adsorption isotherms revealed that biodegradable NPs exhibited distinct adsorption behaviors for PFOS, fitting the Freundlich model and demonstrating a higher affinity than conventional NPs. Dietary exposure modeling suggests that frequent use of biodegradable takeout containers could result in an estimated annual MPs and NPs intake of 8.5-16.6 g per person. These findings highlight a critical paradox wherein the structural instability essential for end-of-life degradation inadvertently compromises usage-phase safety, necessitating the urgent need to address particle shedding and contaminant carrier risks in green packaging.