Considerations for Developing Alternative Health Risk Assessment Approaches for Addressing Multiple Chemicals, Exposures and Effect (External Review Draft)
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In EPA's 2003 Framework for Cumulative Risk Assessment, cumulative risk assessment is defined as the evaluation of risks from exposures to multiple chemicals and other stressors, and having a population focus rather than a source-to-receptor focus. Several reports and environmental justice concerns published over the past 11 years have highlighted the importance of estimating cumulative risks. EPA has published several guidance documents dealing with specific aspects of cumulative risk, such as chemical mixture risk assessment, planning and scoping, stakeholder involvement, and the toxicity from a mixture of pesticides sharing a common mode of action. This draft document is one contribution to EPA's efforts to address issues related to cumulative health risk assessment.
Existing EPA guidance addresses some of the aspects of cumulative risk, but none addresses all of the combinations of multiples included in this report, such as consideration of the composite impact of multiple health effects. Among the distinctive new approaches are:
- grouping chemicals based on exposure characteristics and toxic endpoints for use in applying chemical mixtures risk assessment methods,
- assessing multi-route exposure combinations using relative potency factors,
- integration of categorical regression modeling of multiple effects with additivity approaches, and
- emphasis on the iteration and collaboration between exposure assessment and dose-response assessment to ensure compatible and relevant information.
- Areas of cumulative health risk assessment emphasized in this report can often be performed with existing information.
- Exposure and toxicity characterizations of mixtures are strongly dependent on mixture composition (chemicals and concentrations) and timing of exposures and health effects.
- Qualitative and semiquantitative approaches provided can simplify the number of potential combinations of chemicals, exposures, and effects to make the cumulative health risk assessment more feasible.
|Feb 2001||NCEA began work developing cumulative risk approaches and information through an Interagency Agreement with the Department of Energy.|
|May 2003||EPA releases the Framework for Cumulative Risk Assessment|
|Mar 2006||EPA releases the Considerations for Developing Alternative Health Risk Assessment Approaches for Addressing Multiple Chemicals, Exposures and Effect (External Review Draft) for public review and comment.|
|May 2006||EPA hosts an external peer review workshop for considerations for Developing Alternative Health Risk Assessment Approaches for Addressing Multiple Chemicals, Exposures and Effect.|
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