National Assessment of PFAS in Landfill Leachate in China: Non-Negligible Ultrashort-Chain Components and Socioeconomic Impacts

The persistent leaching of per- and polyfluoroalkyl substances (PFAS) from landfills poses significant environmental risks, particularly to surrounding water systems. However, information regarding the occurrence and fate of PFAS in landfills across the country is limited. Here we investigated the distribution profiles and sources of 60 PFAS in landfill leachate across 31 provinces in mainland of China, showing the total levels of ∑PFAS from 3.05 × 10³ to 1.58 × 10⁵ ng/L. Structural equation modeling revealed that socioeconomic conditions directly influenced the residue levels of PFAS in landfill leachate. Furthermore, these conditions, in conjunction with climatic factors, influenced the chemical composition of landfill leachate, thereby indirectly affecting the distribution of PFAS. The estimated ∑PFAS emission flux from landfill leachate in China was 419 kg/year, with ultrashort-chain congeners as the predominant, omnipresent congeners, accounting for 37%. Our study first provided comprehensive evidence to demonstrate landfills were important sources of PFAS in China, which would help to understand the ecological risks of emerging PFAS, especially for ultrashort-chain PFAS, and eventually promoting the conduction effective environmental monitoring and pollution control strategies for PFAS.