NTP finds PFAS chain length affects elimination time in rats
Researchers from the Division of the National Toxicology Program (NTP) evaluated the toxicokinetics (TKs) of several poly- and perfluorinated alkyl substances (PFAS) in rats. PFAS are chemicals that are used in manufacturing nonstick properties in products and for other uses, such as fire-fighting foams. The study reported a correlation between PFAS chain length and TK properties, namely, that longer chain lengths displayed longer elimination times.
TK studies examine the rate at which a compound enters and leaves the body, while providing some information on the efficiency of its metabolic degradation. The chemical structures of most PFAS are stable, meaning the chemicals tend to persist in the environment and are not metabolically degraded, which increases human exposure. To address TK variability among PFAS, male and female rats were exposed by oral or intravenous administration to three carboxylate PFAS: perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA), and perfluoerodecanoic acid (PFDA). The scientists measured concentrations in several tissues at different time points.
Although other researchers have conducted PFAS toxicity studies, TK studies are necessary to better understand the variability of exposure in the PFAS subclasses. This study provided a rigorous comparison of TK properties across a PFAS subclass. The data, along with existing toxicity studies, are necessary to extrapolate the animal results to humans, which may affect regulations of these chemicals. (VP)
Citation: Dzierlenga AL, Robinson VG, Waidyanatha S, DeVito MJ, Eifrid MA, Gibbs ST, Granville CA, Blystone CR. 2019. Toxicokinetics of perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA) and perfluorodecanoic acid (PFDA) in male and female Hsd:Sprague dawley SD rats following intravenous or gavage administration. Xenobiotica; doi: 10.1080/00498254.2019.1683776 [Online 7 November 2019].