Dietary intakes association with plasma per- and polyfluoroalkyl substances (PFAS) concentrations: A cross-sectional human biomonitoring study in Singapore

Singapore's total diet study (2021-2023) revealed the presence of per- and polyfluoroalkyl substances (PFAS) in food items, alluding to potential dietary exposure pathways. However, evidence-based assessment of human PFAS exposure is lacking across Singapore's multi-ethnic communities. To address this gap, we established a human biomonitoring study to estimate baseline PFAS exposure and their associations with dietary intakes. We recruited 300 participants aged 21-60 years from three major ethnic groups and collected blood plasma samples for PFAS analysis using a targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. Diet was assessed using a validated food frequency questionnaire. Eleven PFAS were detected with median concentrations ranging from 0.05 to 2.56 ng/mL. The detection of perfluorooctanesulfonic acid (PFOS), perfluorooctanoate acid (PFOA) and perfluorononanoic acid (PFNA) in all study participants reflected co-exposure to these PFAS. Total plasma PFAS were significantly higher in middle-aged adults, males and significantly lower in Indians. Multiple linear regression analyses identified poultry, seafood and grains as three major food groups positively associated with plasma PFAS concentrations in the study participants, where seafood showed the most significant associations. Within the seafood category, bivalve molluscs consumption exhibited strong associations across all PFAS. These findings provided insights into the baseline dietary PFAS exposure in a multi-ethnic Singapore population and highlighted potential diet-PFAS relationships that can inform exposure-reduction strategies and risk communication.