USEtox Prioritization Indices for Chemical Exposure from Consumer Products (USEtoxPI)

Olivier Jolliet1, Lesa Aylward2, Michael Hauschild3, Dik van de Meent4, Mark Huijbregts4, Thomas McKone5, Manuele Margni6, Andrew Henderson1, and Donald Patterson7. 1Department of Environmental Health Sciences, School of Public Health, University of Michigan, 2Summit Toxicology, LLP, 3Department of Management Engineering, Technical University of Denmark, 4National Institute of Public Health and the Environment (RIVM), Bilthoven & Radboud University Nijmegen, 5University of California Berkeley, and Lawrence Berkeley National Laboratory, Berkeley, 6CIRAIG, École Polytechnique de Montréal, 7EnviroSolutions Consulting, Inc.

This project creates a novel, augmented model to derive exposure prioritization indices for chemical screening. The project team brings world-class expertise in life cycle assessment, consumer product emissions, multimedia modeling, physiologically based toxicokinetic modeling (PBTK), and biomarker data analysis. The result is the first model to span the continuum from product life-cycle to body burden, ensuring a consistent integration of exposure with the U.S. Environmental Protection Agency (EPA)’s ToxPi toxicity index.

The augmented model will be based on USEtox, the United Nations Environment Programme-Society for Environmental Toxicology and Chemistry (UNEP-SETAC) consensus model, extending it to connect consumer products and workplace exposures to biologically relevant internal doses. Direct releases from consumer products will be adapted from the European Centre for Ecotoxicology and Toxicology of Chemicals Targeted Risk Assessment (ECETOC TRA). Capitalizing on PBTK models, we will develop new correlations on human absorption and removal rates, and evaluate predicted body burdens against the U.S. National Health and Nutrition Examination Survey (NHANES) biomarkers.

This project aims to conduct the following five main tasks, which are described below along with the project year(s) in which the main deliverable will be delivered for each task:

  1. Extend the USEtox matrix framework from consumer exposure to internal dose: This will involve adding matrices for direct chemical emissions from products and for external to internal dose and then combining USEtox with the EPA ToxPi tool to create the USEtoxPI framework. This will result in the first framework linking consistently life cycle emissions to body burden (year 1).
     
  2. Extend the model to cover direct product exposure: This will include customizing and extending USEtoxPI for (a) direct exposure from products; (b) personal care products; c) direct use of pesticides, including indoor use by customers and residues in food products; and d) ionizable chemicals. This will result in the first model to include consumer exposure in a life cycle perspective (years 1 and 3).
     
  3. Create module relating external to internal dose: This task will take advantage of steady-state toxicokinetic modeling and data to derive new correlations for human absorption and removal rates. This will result in new physiologically based pharmacokinetic correlations for human absorption and removal rates (year 2).
     
  4. Determine USEtoxPI prioritization indices: This phase will apply USEtoxPI to the existing USEtox chemical database to produce 3000+ prioritization indices for exposure screening (years 1 and 2).
     
  5. Evaluate influence of spatialization and population heterogeneity on USEtoxPI, with identification of key factors of influence: This task includes developing a spatialized version of USEtoxPI and determining, through systematic sensitivity and uncertainty analyses, the degree to which consumer product exposure variations, model geographic refinement, and heterogeneity of the receiving population affect prioritization indices (year 3). 


Implications

Currently, a significant research effort is underway to apply technology to screen and prioritize chemicals for toxicity. US EPA’s ExpoCastTM is a parallel effort to ensure that the required exposure science, data, and tools are available to address immediate needs for rapid characterization of exposure potential for prioritization and chemical risk management. This project extends and applies an international consensus model to develop exposure classification indices that can be incorporated with the toxicity information in EPA’s ToxPi framework. This innovative model is the first model to span the continuum from product life-cycle to body burden, ensuring a consistent integration of exposure with the EPA’s ToxPi toxicity index.

Keywords

exposure prioritization indices, environmental health, exposure modeling, exposure screening tools

Project Start and End Dates

March 2011 – October 2013

Project ID

MTH1001-01

Peer-reviewed Publication(s)

None to date.

Other Publication(s)

None to date.

Abstract Creation Date

June 2011

*This abstract was prepared by the principal investigator for the project.

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