Integral Consulting Inc.
Dr. Janet Anderson is a human health toxicologist and environmental risk assessor with 15 years of experience providing toxicology expertise and consultation to federal agencies and industry. She specializes in the translation of human health toxicology data into state and federal regulatory and policy decisions and she often performs critical reviews of federal and state risk assessment guidance and regulations. Dr. Anderson’s areas of expertise include emerging contaminants, such as per- and polyfluoroalkyl substances (PFAS), 1,4 dioxane, and 1,2,3-trichloropropane. With in-depth knowledge of federal and state environmental guidance and policies, she has helped clients develop strategies to mitigate their human health impacts and address associated environmental liability for unregulated contaminants. In addition, she tracks the dynamic regulatory changes for emerging contaminants in the U.S. and internationally, offering clients the technical basis for disparate guidelines worldwide. She has extensive experience developing risk management strategies for multi-stakeholder groups and has provided litigation support for various clients with lawsuits involving unregulated or emerging contaminants. Dr. Anderson is a diplomate of the American Board of Toxicology and was formerly a postdoctoral fellow for the EPA Office of Research and Development, National Center for Environmental Assessment and a subject matter specialist in environmental toxicology for the U.S. Department of Defense. She is often an invited speaker at scientific and trade association conferences, regulatory meetings, webinars, and public community stakeholder meetings.
Session #7 - PFAS and 1,4-Dioxane Toxicology Issues
Internal and External Dosimetry - The Holy Grail to Decoding Perfluoroalkyl Acid Toxicity?
Human relevance of rodent effects; mode of action; sensitive endpoint selection; adaptive and adverse responses; background and non-drinking water source contributions; internal kinetics; relative potency estimation; these are all subjects of differing scientific opinion and areas of on-going research for perfluoroalkyl acids (PFAAs). Much of the scientific debate on PFAAs has focused on the mode of action and human relevance of endpoints observed in laboratory rats and mice. Indeed, ATSDR determined that rodent PFAA data are not appropriate to inform dose-response in humans due to uncertainties in mode of action and kinetics (absorption, distribution, metabolism, elimination). In particular the extremely variant half-lives between rodents and humans for this class of compounds emphasizes the necessity for accurate understand and quantification of kinetic differences for PFAAs. Quantifying external to internal dosimetry and related target-site exposure is critical for PFAAs and underscores the potential utility of biomonitoring and occurrence data. Herein, we explore the disparate ways that regulatory agencies have quantitatively accounted for species differences in biokinetics of PFAAs, without establishing a rigorous framework for addressing uncertainty given important data gaps. We demonstrate that these factors profoundly impact the final quantitative derivation of human threshold criteria. We propose that in vitro-in vivo extrapolation (IVIVE) and physiologically based pharmacokinetic (PBPK) modeling are important tools for unraveling species differences, life-stage sensitivities, influence of background exposures, and ultimately guiding decisions for human health risk assessment of PFAAs. We present data on biomonitoring, background non-drinking water source exposures, external to internal dose ratios, and other available data that can inform such models. Specific research questions and areas for further investigation are identified.