Assessment of modeled serum per- and polyfluoroalkyl substances concentrations from exposure estimates for pregnant women in the general population in comparison to previously measured serum concentrations

When drinking water is uncontaminated, exposure to PFAS is thought to occur primarily via ingestion of food and indoor dust. To understand the background exposure during prenatal periods, this study examined whether published estimates of PFAS exposure rates from dietary and dust ingestion provide reasonable predictions of PFAS serum concentrations among pregnant women in the general population. This study estimated serum concentrations of four PFAS during pregnancy based on published PFAS intake rates for food and indoor dust reported in the peer-reviewed literature, a pharmacokinetic model using two different sets of parameters, and Monte Carlo simulation to account for variability/uncertainty. Historical dietary ingestion rate was reconstructed using serum PFAS concentrations of pregnant women from NHANES. The estimated serum concentrations for different exposure scenarios were then compared with measured maternal serum levels reported in published studies of populations without known PFAS water contamination. Mother-child dyad models showed no substantial change in serum PFAS concentrations during pregnancy. Lower published estimates of dietary intake and historical reconstruction, resulted in good prediction of maternal serum concentrations for PFOA, PFOS, and PFHxS. Higher published estimates of dietary intake overestimated maternal serum concentrations, especially for PFNA. Although some discrepancies exist among published estimates of indoor dust intake, half-life, and volume of distribution for PFAS, any combination of selected estimates from literature along with lower published dietary intake estimates are sufficient to provide reasonable prediction of maternal serum concentrations at population-level.