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Activity Number:
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109
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Type:
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Contributed
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Date/Time:
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Monday, August 7, 2006 : 8:30 AM to 10:20 AM
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Sponsor:
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Section on Statistics and the Environment
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| Abstract - #306638 |
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Title:
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Empirical Evaluation of Sufficient Similarity in Dose-Responsiveness for Environmental Risk Assessment of Chemical Mixtures
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Author(s):
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LeAnna G. Stork*+ and Chris Gennings and W. Hans Carter, Jr. and Linda Teuschler and Edward W. Carney
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Companies:
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Monsanto Company and Virginia Commonwealth University and Virginia Commonwealth University and U.S. Environmental Protection Agency and The Dow Chemical Company
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Address:
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800 N. Lindbergh Blvd., St Louis, MO, 63167,
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Keywords:
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equivalence testing ; mixed models
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Abstract:
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When toxicity data are not available for a chemical mixture of concern, U.S. EPA guidelines allow risk assessment to be based on data for a surrogate mixture considered "sufficiently similar". As a supplementary approach we develop statistical methodology to define sufficient similarity in dose-responsiveness for mixtures of many chemicals containing the same components with different ratios. Statistical equivalence testing logic is applied to determine boundary ratios for mixtures with mean dose-response relationships sufficiently similar to an observed mixture, based on a specified biologically meaningful dose-response region of similarity. The similarity region is defined by the investigator or regulator using expert biological judgment. Dose-response data from Rajapakse et al. (EHP, 2002) are used to illustrate the method. (This research is not associated with Monsanto Co.)
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