A Simple Pharmacokinetic Model of Prenatal and Postnatal Exposure to Perfluoroalkyl Substances (PFASs)

Most children are exposed to perfluoroalkyl
substances (PFASs)
through placental transfer, breastfeeding, and other environmental
sources. To date, there are no validated tools to estimate exposure
and body burden during infancy and childhood. In this study, we aimed
to (i) develop a two-generation pharmacokinetic model of prenatal
and postnatal exposure to perfluorooctanoic acid (PFOA), perfluorooctanesulfonate
(PFOS), and perfluorohexanesulfonate (PFHxS); and to (ii) evaluate
it against measured children’s levels in two studies. We developed
a pharmacokinetic model consisting of a maternal and a child compartment
to simulate lifetime exposure in women and transfer to the child across
the placenta and through breastfeeding. To evaluate the model, we
performed simulations for each mother–child dyad from two studies
in which maternal PFAS levels at delivery and children’s PFAS
levels were available. Model predictions based on maternal PFAS levels,
sex of child, body weight, and duration of breastfeeding explained
between 52% and 60% of the variability in measured children’s
levels at 6 months of age and between 52% and 62% at 36 months. Monte
Carlo simulations showed that the daily intake through breastfeeding
and resulting internal PFAS levels can be much higher in nursing infants
than in mothers. This pharmacokinetic model shows potential for postnatal
exposure assessment in the context of epidemiological studies and
risk assessment.