Cited by 156Per- and polyfluoroalkyl substances researchToxic Organic Pollutants ImpactEnvironmental Toxicology and Ecotoxicology

Application of a Framework for Grouping and Mixtures Toxicity Assessment of PFAS: A Closer Examination of Dose-Additivity Approaches

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Goodrum, Philip E, Anderson, Janet K, Luz, Anthony L, Ansell, Graham K·2021·Toxicological Sciences

Abstract

Environmental occurrence and biomonitoring data for per- and polyfluoroalkyl substances (PFAS) demonstrate that humans are exposed to mixtures of PFAS. This article presents a new and systematic analysis of available PFAS toxicity study data using a tiered mixtures risk assessment framework consistent with United States and international mixtures guidance. The lines of evidence presented herein include a critique of whole mixture toxicity studies and analysis of dose-response models based on data from subchronic oral toxicity studies in rats. Based on available data to-date, concentration addition and relative potency factor methods are found to be inappropriate due to differences among sensitive effects and target organ potencies and noncongruent dose-response curves for the same effect endpoints from studies using the same species and protocols. Perfluorooctanoic acid and perfluorooctane sulfonic acid lack a single mode of action or molecular initiating event and our evaluation herein shows they also have noncongruent dose-response curves. Dose-response curves for long-chain perfluoroalkyl sulfonic acids (PFSAs) also significantly differ in shapes of the curves from short-chain PFSAs and perfluoroalkyl carboxylic acids evaluated, and additional differences are apparent when curves are evaluated based on internal or administered dose. Following well-established guidance, the hazard index method applied to perfluoroalkyl carboxylic acids and PFSAs grouped separately is the most appropriate approach for conducting a screening level risk assessment for nonpolymeric PFAS mixtures, given the current state-of-the science. A clear presentation of assumptions, uncertainties, and data gaps is needed before dose-additivity methods, including hazard index , are used to support risk management decisions. Adverse outcome pathway(s) and mode(s) of action information for perfluorooctanoic acid and perfluorooctane sulfonic acid and for other nonpolymer PFAS are key data gaps precluding more robust mixtures methods. These findings can guide the prioritization of future studies on single chemical and whole mixture toxicity studies.

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  • Given existing differences in toxicokinetics and mechanisms of action, and the lack of comprehensive data, the development of a TEF approach for perfluoroalkyl chemicals remains a distant goal rather than a scientifically established outcome.

    “Overall, given the existing differences in toxicokinetics and mechanisms of action, and the lack of comprehensive data, the development of a TEF approach for perfluoroalkyl chemicals remains a distant goal rather than a scientifically established outcome [53,54,55].”

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Research works printed but not linked: 2

  1. National Research Council. (2008) Phthalates and Cumulative Risk Assessment. The Task Ahead National Academies Press, Washington, DC. 25009926
  2. Patlewicz G. (2019) Perspectives on the development, evaluation and application of in silico approaches for predicting toxicity. The United Stated Environmental Protection Agency's Center for Computational Toxicology and Exposure. Presentation. 10.23645/epacomptox.10299371.v1. · DOI

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Authors
Goodrum, P. E., Anderson, J. K., Luz, A. L., & Ansell, G. K.
Affiliations
  • GSI Environmental (United States) (US)
  • Integral Consulting Inc, Annapolis, Maryland 21401
Corresponding author
Goodrum, Philip E
Venue
Toxicological Sciences
Published
2020-07-31
Volume
179
Issue
2
Pages
262-278
ISSN
  • 1096-0929 (ISSN-L)
  • 1096-6080
OpenAlex
W3046774067
Cited by
118
References
76
Citations by year
2026: 18 · 2025: 20 · 2024: 31 · 2023: 13 · 2022: 23 · 2021: 13
FWCI
4.64
Type
journal article
Language
en
Open access
Locations
  • Toxicological Sciences (publishedVersion, cc-by-nc)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by-nc)
  • PubMed Central (publishedVersion, cc-by-nc)
  • PubMed (publishedVersion)
Funders
FluoroCouncil of the American Chemistry Council
Topics
  • Physical Sciences › Environmental Science › Environmental Chemistry › Per- and polyfluoroalkyl substances research
  • Physical Sciences › Environmental Science › Health, Toxicology and Mutagenesis › Toxic Organic Pollutants Impact
  • Physical Sciences › Environmental Science › Health, Toxicology and Mutagenesis › Environmental Toxicology and Ecotoxicology
Keywords
per- and polyfluoroalkyl substances, PFAS mixtures, dose additivity, hazard index, concentration addition, relative potency factors, dose-response curves, perfluorooctanoic acid, PFOS, perfluorinated carboxylic acids, perfluoroalkyl sulfonic acids, subchronic oral toxicity, mechanism of action, adverse outcome pathways, screening-level risk assessment
MeSH terms
Adverse Outcome Pathways, Animals, Carboxylic Acids, Fluorocarbons, Sulfonic Acids, Alkanesulfonic Acids, Risk Assessment, Rats

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