PFAS PK Challenges

Per- and Polyfluoroalkyl substances (PFAS) are a class of persistant chemicals to which most individuals are commonly exposed. Due to the ubiquity of exposure and links to toxic effects in animal and epidemiological studies, the need for chemical risk assessment of these chemicals is apparent. One challenge to risk assessors is the difficulty in applying dosimetric methods to PFAS due to thier high affinity interactions with transporters and binding proteins. These interactions can result in non-linear pharmacokinetics and in kinetics that differ by sex and age. This presentation briefly summarizes some of the challenges in applying dosimetric methods to PFAS and some of the possible solutions and ongoing work to address these issues.

Impact/Purpose

This presentation was given to the National Academies of Science Committee on Toxicology. The context was that US EPA researchers were invited to share some of their experience in perfoming risk assessment of PFAS, particularly in the application of dosimetry methods. This 15-min presentation addresses some of the challenges experienced in applying PBPK models for PFAS (specifically PFHxS, PFNA, and PFDA). Current data gaps and ongoing work to resolve these issues is discussed.

Citation

Dzierlenga, M., P. Schlosser, D. Kapraun, T. Zurlinden, V. Morozov, AND A. Bernstein. PFAS PK Challenges. Considerations on Development of DOD Exposure Limits for Current PFAS Compounds (Virtual), DC, DC, July 21, 2022.