Per- and polyfluoroalkyl substances (PFASs) is a collective term for several subclasses of manmade chemicals, which have been produced for decades and are still being produced in high tonnages. Due to their unique physicochemical properties, these chemicals are applied in multiple products including paints, packaging materials and textiles. Human exposure can be investigated by biomonitoring or by combining external exposure media levels with knowledge of intake or uptake processes. In this critical review, we focus on the exposure during early life-stages of humans, which we refer to as infants, toddlers, other children and adolescents based on definitions by the European Food Safety Authority.
Due to the dynamic developmental processes during pregnancy, infancy, childhood and adolescence, exposure to PFASs is hypothesized to have the most pronounced negative effects during this period. In this review we critically evaluate the current state of the science regarding human early life exposure processes (until 18 years of age) to per- and polyfluoroalkyl substances (PFASs). Efficient placental transfer of perfluoroalkyl acids (PFAAs) results in relatively high prenatal exposure compared with many neutral organic contaminants. The few biomonitoring studies that specifically target infants, toddlers and other children suggest relatively high serum concentrations of perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in early life with peak concentrations occurring sometime before the child reaches 20 months. This peak in serum concentrations is most likely explained by exposure via breastfeeding, ingestion of house dust and/or specific contact events with consumer products leading to high body weight normalized estimated daily intakes (EDIs). Although children have higher EDIs of PFASs than adults, these are not always reflected by higher serum levels of PFASs in children in cross-sectional biomonitoring studies due to the confounding effect of age and birth cohort, and different exposure histories due to production changes. Longitudinal exposure studies measuring internal and external exposure (for multiple pathways and PFASs) at several time points during early life are strongly encouraged to understand temporal changes in exposure of individual children. A better quantitative understanding of early life exposure processes would help to improve the validity of epidemiological studies and allow informed decisions regarding setting of regulatory thresholds and appropriate mitigation actions.
Coworkers: Robin Vestergren
Report number: A2289
Authors: Robin Vestergren, Winkens, K., Berger, U., & Cousins, I. T.