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The 2022 world health organization reevaluation of human and mammalian toxic equivalency factors for polychlorinated dioxins, dibenzofurans and biphenyls
Citation:
Devito, M., B. Bokkers, M. van Duursen, K. van Ede, M. Feeley, E. Antunes Fernandes Gaspar, L. Haws, S. Kennedy, R. Peterson, R. Hoogenboom, K. Nohara, K. Petersen, C. Rider, M. Rose, S. Safe, D. Schrenk, M. Wheeler, D. Wikoff, B. Zhao, AND M. van den Berg. The 2022 world health organization reevaluation of human and mammalian toxic equivalency factors for polychlorinated dioxins, dibenzofurans and biphenyls. REGULATORY TOXICOLOGY AND PHARMACOLOGY. Elsevier Science Ltd, New York, NY, 146:105525, (2024). https://doi.org/10.1016/j.yrtph.2023.105525
Impact/Purpose:
In October 2022, World Health Organization (WHO) convened an expert panel in Lisbon Portugal in which the 2005 WHO TEFs for dioxin like compounds, including some polychlorinated biphenyls (PCBs), were reevaluated. In contrast to earlier panels that employed expert judgement and consensus-based assignment of TEF values, the present effort employed an update to the 2006 REP database, a consensus-based weighting scheme and a Bayesian dose response fitting scheme and meta-analysis to derive “Best-Estimate” TEFs. The updated database contains almost double the number of datasets from the earlier version and includes metadata that forms the basis of the weighting scheme. The Bayesian analysis of this dataset results in an unbiased quantitative assessment of the congener-specific potencies with an accompanying uncertainty estimate. The “Best-Estimate” TEF derived from the model was used to assign 2022 WHO-TEFs for almost all congeners and these values were not rounded to half-logs as was done previously. The exception was for the mono-ortho PCBs, for which the panel agreed to retain their 2005 WHO-TEFs due to limited and heterogenous data available for these compounds. Applying these new TEFs to a limited set of dioxin-like chemical concentrations measured in human milk and seafood indicates that the total toxic equivalents will tend to be lower than when using the 2005 TEFs.
Description:
In October 2022, the World Health Organization (WHO) convened an expert panel in Lisbon, Portugal in which the 2005 WHO TEFs for chlorinated dioxin-like compounds were reevaluated. In contrast to earlier panels that employed expert judgement and consensus-based assignment of TEF values, the present effort employed an update to the 2006 REP database, a consensus-based weighting scheme, a Bayesian dose response modeling and meta-analysis to derive “Best-Estimate” TEFs. The updated database contains almost double the number of datasets from the earlier version and includes metadata that informs the weighting scheme. The Bayesian analysis of this dataset results in an unbiased quantitative assessment of the congener-specific potencies with uncertainty estimates. The “Best-Estimate” TEF derived from the model was used to assign 2022 WHO-TEFs for almost all congeners and these values were not rounded to half-logs as was done previously. The exception was for the mono-ortho PCBs, for which the panel agreed to retain their 2005 WHO-TEFs due to limited and heterogenous data available for these compounds. Applying these new TEFs to a limited set of dioxin-like chemical concentrations measured in human milk and seafood indicates that the total toxic equivalents will tend to be lower than when using the 2005 TEFs.
URLs/Downloads:
DOI: The 2022 world health organization reevaluation of human and mammalian toxic equivalency factors for polychlorinated dioxins, dibenzofurans and biphenyls
https://pubmed.ncbi.nlm.nih.gov/37972849/