Aggregate exposure assessment

ILSl, A Framework for Estimating Pesticide Concentrations in Drinking Water for Aggregate Exposure Assessments, Workshop Report 5/19/99. International Life Sciences Institute, Washington, DC (1999). 

Until very recently the risks associated with different types of chemicals such as food additives, pesticides, environmental contaminants and natural constituents of food were assessed and managed separately. However, a particular substance might fall into two or more of these categories and so the opportunity for simultaneous exposure might be overlooked. Furthermore, exposure to a chemical could occur through diet, drinking water, air pollution or dermal absorption. Aggregate exposure assessment aims to take all of the possible sources and routes of exposure into account in a realistic manner and thereby obtain a better overall estimate of risk. Initiatives have been set up in both the... 

Aggregate exposure assessment is naturally more complex than the methods used for dietary risk assessment. In the simplest analysis a worst case can be established for each source and exposure route and then summed to give a total exposure. If this were below any threshold of concern such as the PTWI then no further action would be required. However, if the total worst case exposure was above a PTWI then it is unlikely to reflect the real situation since the probability that any individual would be exposed to each source by each route at the maximum level is very remote. 

ILSI (1998). International Life Science Institute Risk Science Institute. Workshop on Aggregate Exposure Assessment. Washington, DC. 

ILSI (1998). Aggregate Exposure Assessment, Workshop, 9-10 February, International Life Sciences Institute (Risk Science Institute), ILSI Press, Washington, DC, USA (website http //www.ilsi.org/file/rsiaggexp.pdf). 

Aggregate exposure assessment A process for developing an estimate of the extent of exposure of a defined population to a given chemical by all relevant routes and from all relevant sources (ILSI, 1998). 

Figure 1 Components of multi-pathway, multi-route aggregate exposure assessment.

Therefore, to estimate or measure aggregate exposures, relevant and reliable data are required. Further, aggregate exposure assessment methods and modeling tools are needed that more accurately reflect real-life situations (in contrast to methods and models that are based on very conservative assumptions and may lead to less realistic and sometimes gross overestimates of exposure). 

USEPA (1997) Office of Pesticide Programs. Aggregate Exposure Assessment as Required by the Eood Quality Protection Act (EQPA) of 1996 - Interim Approach Issue Paper for the March 1997 Scientific Advisory Panel (SAP) Meeting. 

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