Serum PFAS exposure in school-aged (6–12 years old) children: Association with dietary intake

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are persistent, bioaccumulative, and toxic environmental contaminants of global concern. Thus, accurate and sensitive detection methods are urgently required to assess human exposure to emerging PFAS. In this study, we developed and validated a highly sensitive LC–MS/MS method for the simultaneous quantification of 19 PFAS in serum, including nine legacy compounds, six short-chain alternatives, and four emerging substitutes, using solid-phase extraction (SPE) for matrix clean-up. The method showed satisfactory recoveries (62.9–131%) and precision (relative standard deviation: 0.347–17.0%) rates, with lower detection limits than previously reported assays. Application to serum samples from 258 children (6–12 years old) from Wuxi revealed widespread PFAS exposure, characterized by high detection frequencies and increased concentrations. Fifteen PFAS were detected in over 80% of samples, including seven legacy compounds, six short-chain alternatives, and two emerging substitutes, with 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA)—a China-specific perfluorooctanoic acid (PFOS) alternative—reaching 5.16 ng·mL -1 . The multiple linear regression model revealed inverse associations between serum PFAS concentrations and age, BMI, and maternal educational level. Higher fish and vegetable intakes may be associated with increased serum concentrations of several PFAS, including perfluorononanoic acid, perfluorodecanoic acid, perfluoroundecanoic acid, perfluorododecanoic acid, perfluorotridecanoic acid, PFOS, and 6:2 Cl-PFESA, indicating that diet could contribute to children’s internal PFAS burden. These findings demonstrate the utility of the optimized analytical method for comprehensive exposure assessment and provide insights into the potential sources of PFAS exposure in school-aged children, particularly from dietary sources.