Developmental toxicity of emerging perfluoroalkyl substances (PFAS) in North Carolina

This is an invited research seminar at UNC-Asheville that will be presented virtually and there is no associated abstract.

Impact/Purpose

Per- and poly-fluoroalkyl substance (PFAS) research is an area of critical need due to issues associated with environmental persistence, widespread occurrence, biological half-life, toxicity, and nearly ubiquitous human and environmental exposure. Perfluoroalkyl ether acids (PFEAs) are a sub-class of PFAS and include the compounds hexafluoropropylene oxide dimer acid (GenX) and Nafion byproduct 2 (NBP2). PFEAs are currently used in the production of fluoropolymers following the phase-out of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), presumably due to more favorable fate and toxicity profiles. However, monitoring studies have detected GenX, NBP2, and others in a wide range of matrices including surface water, drinking water, and/or human serum. Little published research is available regarding the potential toxicity of these compounds compared to the legacy PFAS or cumulative effects of exposure to PFAS mixtures. We hypothesized that in utero exposure to GenX would impact the maternal liver during gestation and potentially lead to adverse neonatal effects, similar to other PFAS, and that mixture exposures would produce dose additive effects. The data from this project will be useful to state, federal, and other regulatory agencies in the development of hazard assessments for GenX and NBP2, among other PFAS and combined exposure to multiple PFAS. This study characterizes the toxic effects of oral GenX, NBP2, and a PFAS mixture exposure during pregnancy to both the mother and the offspring (fetal and newborn) using a laboratory rat model. We found multiple, severe effects for GenX and NBP2 that were consistent with other PFAS, such as PFOA and PFOS. Importantly, it appears that NBP2 is only slightly less potent than PFOS and GenX is only slightly less potent than PFOA based on the orally administered dose. Further, combined exposure to multiple PFAS produce dose additive effects. The data presented here will be highly valuable for regulators to make scientifically based decisions on the potential adverse effects of NBP2 on human health and informing future toxicity studies of additional PFAS.

Citation

Conley, J. Developmental toxicity of emerging perfluoroalkyl substances (PFAS) in North Carolina. UNC Asheville Chemistry & Biochemistry Seminar Series, NA virtual, NC, February 12, 2021.