Distribution of Per- and Polyfluoroalkyl Substances in Differently Processed Rice and Associated Dietary Exposure Assessment

Abstract Per- and polyfluoroalkyl substances (PFAS) are widely present in the environment and can enter the food chain through various pathways. Rice is a significant exposure pathway of PFAS. However, the impact of processing degrees on PFAS levels in rice and the subsequent dietary risks remain unclear. This study investigated the levels of PFAS in 60 paddy rice samples collected in China using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The average ∑6 PFAS content in paddy rice was 0.2736 ng/g. PFOA, PFOS, and PFNA were the predominant analogues, accounting for 44.2%, 20.8%, and 16.2% of the ∑6 PFAS, respectively. Notably, processing from paddy to well milled rice significantly reduced PFAS residues by 82.16%. Finally, a dietary exposure assessment of PFAS was conducted based on the consumption of rice with different processing levels among different sexes. Research results indicate that high rice consumers may have concerns, while rice processing can significantly reduce this risk.