EPA-Expo-Box (A Toolbox for Exposure Assessors)
Aggregate and Cumulative
Data availability ranges from relatively abundant for many chemical stressors to somewhat sparse for many biological and radiological stressors; almost no information is available for the many other types of stressors (U.S. EPA, 2003). In many cases, data may need to be collected specifically to support a combined risk assessment. For example, data used for a cumulative assessment should ideally “conserve the covariance and dependency structures associated with the [stressors] of concern” [ILSI (1999) as cited in EPA (2003)]. Moreover, because the exposure and dose-response analyses cannot easily be separated in a combined assessment, extremely detailed exposure estimates are only useful when the dose-response data are equally detailed.
Descriptions of the input data for aggregate and cumulative assessments can be found in multiple tool sets on the EPA-Expo-Box website. The Indirect Estimation (Scenario Evaluation) module of the Approaches Tool Set includes the following categories for input data:
Quantitative input data to characterize the effects of non-chemical stressors are often lacking, but recent journal articles and symposia have proposed strategies for incorporating these effects. Refer to:
- Lewis, AS; Sax, SN; Wason, SC; Campleman, SL. (2011). Non-chemical stressors and cumulative risk assessment: An overview of current initiatives and potential air pollutant interactions. International Journal of Environmental Research and Public Health 8:2020-2073.
- Rider, CV; Dourson, ML; Hertzberg, RC; Mumtaz, MM; Price, PS; Simmons, JE. (2012). Incorporating nonchemical stressors into cumulative risk assessments. Toxicol Sci.: 127(1):10-7.