Spatial distribution, compositional characteristics, and source apportionment of legacy and novel per- and polyfluoroalkyl substances in farmland soil: A nationwide study in mainland China

China, as one of the largest global producers and consumers of per- and poly-fluoroalkyl substances (PFASs), faces concerning levels of PFAS pollution in soil. However, knowledge of their occurrence in agricultural soils of China on the national scale remains unknown. Herein, the first nationwide survey was done by collecting 352 soil samples from 31 provinces in mainland China. The results indicated that the Σ24PFASs concentrations were 74.3 - 24880.0 pg/g, with mean concentrations of PFASs in decreasing order of legacy PFASs > emerging PFASs > PFAS precursors (640.2 pg/g, 340.7 pg/g, and154.9 pg/g, respectively). The concentrations in coastal eastern China were distinctly higher than those in inland regions. Tianjin was the most severely PFASs-contaminated province because of rapid urban industrialization. This study further compared the PFAS content in monoculture and multiple cropping farmland soils, finding the concentrations of PFASs were high in soils planted with vegetable and fruit monocultures. Moreover, a positive matrix factorization (PMF) model was employed to identify different sources of PFASs. Fluoropolymer industries and aqueous film-forming foams were the primary contributors. The contributions from different emission sources varied across the seven geographical regions. This study provides new baseline data for prevention and control policies for reducing pollution. The current work focused on the pollution characteristics and sources apportionment of legacy and novel PFASs in agricultural soils in China. PFAS pollution showed significant spatial differences, with legacy PFASs playing a dominant role from a national perspective. Differences were observed in the distribution trends of legacy and novel PFASs. Fruit and vegetable farmland soils exhibited high PFAS residues. Based on a positive matrix factorization model, fluoropolymer industries and aqueous film-forming foams served as the primary sources of PFASs. The contributions from various emission sources were quantified across the seven geographical regions. These quantified results have rarely been reported before.