Subdivision of Uncertainty Factors to Allow for Toxicokinetics and Toxicodynamics |
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Authors: | A. G. Renwick |
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Affiliation: | University of Southampton, Southampton SO16 7PX, UK |
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Abstract: | Tenfold uncertainty factors have been used in risk assessment for about 40 years to allow for species differences and inter-individual variability. Each factor has to allow for toxicokinetic and toxicodynamic differences. Subdividing the 10-fold factors into kinetic and dynamic defaults, which when multiplied give a product of 10, offers a number of advantages. A major advantage is that chemical-specific data can be introduced to replace one or more of the default subfactors, hence contributing to a chemical-related overall factor. Subdivision of the 10-fold factors also facilitates analysis of the appropriateness of the overall 10-fold defaults, and the development of a more refined approach to the use of uncertainty factors. |
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Keywords: | uncertainty factors safety factors acceptable daily intake species differences human variability reference dose |
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