Chapter 50 - Modeling Dietary Exposure with Special Sections on Modeling Aggregate and Cumulative Exposure

Abstract

This chapter focuses on methodology to estimate dietary exposures and provides options that range from worst-case screening assessments to much more refined and accurate assessments. Separate sections describe techniques that can be used to conduct aggregate and cumulative assessments. In many situations other assessment methods are necessary to identify the potential importance of a specific route relative to other pathways of exposure. These methods are generally referred to as indirect methods. Typically, indirect exposures are estimated for each route and then combined in order to estimate total exposure. Again, the three potential routes are oral, dermal, and inhalation. Indirect estimates of consumer exposure to a pesticide require data on the levels in the media as well as estimates of the amount of food consumed, extent of dermal exposure, and inhalation rates. Dietary, cumulative, and aggregate exposure methodologies are discussed in this chapter along with examples of the algorithms and data that can be employed for each method. Exposure assessments can be useful to identify the potential importance of a specific route relative to other pathways of exposure. That is, the method should identify the proportion of exposure that can result from oral, dermal, or inhalation or a combination of these routes. In many cases, exposures from more than one source need to be considered. The methods should allow the user to aggregate exposures as appropriate for the scenarios under consideration. Aggregation may be relevant to one chemical contained in one product that has multiple routes of exposure.