Childhood exposure to per- and polyfluoroalkyl substances in educational environments: Arising from stationery and implications for health

Per - and polyfluoroalkyl substances (PFAS) are ubiquitous in consumer manufacturing, but their occurrence in stationery products and the associated exposure risk to children in educational environments remain unclear. A total of 17 PFAS (Σ 17 PFAS) were quantitatively detected in 53 children's stationery from four categories with the overall detection frequency of 64.5 %. The concentrations of Σ 17 PFAS ranged up to 70.9 ng/g, with a median value of 0.16 ng/g. The precursors in these products were confirmed by total oxidizable precursor assay. Exposure assessment showed that estimated maximum PFAS intake from pen grips via hand-to-mouth contact (0.57 ng/kg-bw/day) approached the tolerable daily intake for children established by the European Food Safety Authority (0.63 ng/kg-bw/day), highlighting a potential concern from the sources in educational environment. To further investigate the potential mechanism of PFAS dermal adsorption, molecular docking analysis was performed to evaluate the affinities of PFAS compounds toward 12 representative tight junction proteins in human skin. The emerging PFAS alternative, perfluorooctylphosphonic acid, demonstrated significantly stronger binding affinity ( p < 0.05) to these tight junction proteins compared to the other analytes. This work preliminarily indicates that childhood exposure to PFAS in educational environments may occur through the use of stationery products, with computational results suggesting a potential role for tight junctions in the dermal absorption and subsequent toxicity of these compounds. • Seventeen PFAS were found in 53 stationery products with detection frequency of 64.5 %. • PFAA precursors were confirmed by the total oxidizable precursor assay. • EDIs calculated via ingestion or dermal contact were below the safety threshold. • Tight junction proteins in human skin may be involved in the dermal adsorption of PFAS.