EPA-Expo-Box (A Toolbox for Exposure Assessors)
Aggregate and Cumulative
Humans and ecological receptors are exposed to multiple stressors via multiple pathways. Considerable attention has been dedicated to assessing how different stressors interact and how overall exposure is influenced by uptake via different routes and pathways. Assessments that examine exposure to more than one stressor and/or route and pathway are considered “combined” exposure assessments. Cumulative and aggregate assessments represent the two major categories of combined exposure assessments currently in use.
Aggregate exposure assessment considers combined exposures to a single stressor across multiple routes and multiple pathways (U.S. EPA, 2003).
Cumulative exposure assessment generally evaluates combined exposure to multiple stressors via multiple exposure pathways (U.S. EPA, 2003) that affect a single biological target. In addition to chemical stressors, cumulative exposure assessments might also take into account non-chemical stressors, such as physical or biological stressors that might impact exposure.