Comparison of aggregated exposure to perfluorooctanoic acid (PFOA) from diet and personal care products with concentrations in blood using a PBPK model – Results from the Norwegian biomonitoring study in EuroMix

Abstract

BackgroundPer- and polyfluoroalkyl substances (PFAS) constitute a large group of compounds that are water, stain, and oil repellent. Numerous sources contribute to the blood levels of PFAS in the European population. The main contributor for perfluorooctanoic acid (PFOA) is food, house dust, consumer products and personal care products (PCPs). ObjectivesThe purpose of the present work is to calculate the dietary and dermal external exposure to PFOA, estimate the aggregated internal exposure from diet and PCPs using a PBPK model, and compare estimates with measured concentrations. MethodsDetailed information on diet and PCP use from the EuroMix study is combined with concentration data of PFOA in food and PCPs in a probabilistic exposure assessment. A physiologically based pharmacokinetic model (PBPK) was further refined by incorporating a dermal exposure pathway, and changes in the kidney and faecal excretion. ResultsThe aggregated internal exposure using the PBPK model shows that the major contributor to the internal exposure is diet for both males and females. The estimated internal exposure of PFOA for the EuroMix population was in the same range but lower than the measured blood concentrations using the lower bound (LB) external exposure estimates, showing that the LB estimates are underestimations. For seven females the internal exposure of PFOA were higher from PCPs than from diet. ConclusionPCPs and diet contributed in the same range to the internal PFOA exposure for several women participating in EuroMix. This calls for additional studies on exposure to PFOA and possibly other PFAS from PCPs, especially for women. Overall, PBPK modelling was shown as valuable tool in understanding the sources of PFOA exposure and in guiding risk assessments and regulatory decisions.