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

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Abstract
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. We recruited 300 healthy participants aged 21–60 years from three major ethnic groups and collected blood plasma samples for PFAS analysis. As the primary exposure, we administered dietary assessment to all participants using a validated food frequency questionnaire. Concurrently we applied a targeted liquid chromatography–tandem mass spectrometry (LC–MS/MS) method for the quantification of 38 PFAS in human plasma. 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 plasma PFAS co-exposure profiles. 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 group predictors 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 delineated potential diet-PFAS relationships that can inform exposure-reduction strategies and risk communication.