Impact of precursors and bioaccessibility on childhood PFAS exposure from house dust

This study investigated the impact of precursors and bioaccessibility on childhood per- and polyfluoroalkyl substances (PFAS) exposure in house dust (n = 28) from Adelaide, Australia. Sum PFAS concentration (∑38) ranged from 3.0 to 2640 μg kg−1 with PFOS (1.5–675 μg kg−1), PFHxS (1.0–405 μg kg−1) and PFOA (1.0–155 μg kg−1) constituting the major perfluoroalkyl sulfonic (PFSA) and carboxylic acids (PFCA). The total oxidizable precursor (TOP) assay was applied to estimate concentrations of unmeasurable precursors that may undergo oxidation to measurable PFAS. Sum PFAS concentration post-TOP assay changed 3.8–112-fold (91.5–62,300 μg kg−1) with median post-TOP assay PFCA (C4-C8) concentrations (92.3–170 μg kg−1) increasing significantly (13.7–48.5-fold). As incidental dust ingestion is a significant exposure pathway for young children, PFAS bioaccessibility was determined using an in vitro assay. Sum PFAS bioaccessibility ranged from 4.6 to 49.3 % with significantly (p