EPA-Expo-Box (A Toolbox for Exposure Assessors)
- Fate & Transport
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Exposure to contaminants in food can be estimated by first defining the exposure scenario of interest. Exposure scenarios typically include information on the sources and pathways of exposure, contaminants of concern, and receptor populations. They may also describe a receptor population’s activities that may affect exposure and the timeframe over which exposure occurs.
For a food ingestion scenario, concentrations of the contaminants in food (modeled or measured) are needed to estimate exposure dose. Information about the receptor population(s) is also important. Any member of the general population could be consuming contaminated food, although the percentage of contaminated food consumed might be diluted if food from a variety of sources is consumed. Because nursing infants obtain most—if not all—of their dietary intake from human milk, they are especially vulnerable to exposures to compounds in breast milk (see the module on Lifestages in the Lifestages and Populations Tool Set in EPA-Expo-Box).
After characterizing the exposed population and identifying exposure concentrations, it is important to define all appropriate exposure factor inputs to estimate potential exposures and risks. These inputs (e.g., intake rates, body weights, and relevant patterns of behavior such as timeframe of exposure) can be obtained from the Exposure Factors Handbook: 2011 Edition (see Exposure Factors tab in the Indirect Estimation Module of Approaches Tool Set). Ingestion of contaminated foods could occur over short durations (e.g., breastfeeding infant) or longer time periods (e.g., residence time for a receptor consuming homegrown food).
The table below provides some examples of scenarios involving contaminants in food. The list of examples is not meant to be exhaustive; there are numerous other food ingestion scenarios that may be constructed based on the specific needs of the assessment. There are also many variations of the examples provided in the table. Additional information on exposure scenarios involving contaminated food may be found in the Indirect Estimation Module of the Approaches Tool Set in EPA-Expo-Box.
|Medium||Receptor Population||Activity/Timeframe||Intake Rate||Exposure Period|
|Fruits||General population; consumer-only adults||Ingestion of fruits; short term||Total fruit intake rate
|Meat products||General population; per capita adults||Ingestion of meat; long term||Total meat intake rate
|Dairy products||General population; children ages 1 - 6 years||Ingestion of milk; long term over 5 years||Total diary intake
|Homegrown vegetables||Home gardeners||Ingestion of home-produced vegetables; long term||Intake of home-produced vegetables
|Grain products||General population, consumer-only adults||Ingestion of grain||Intake of total grains
|Human milk||Infants||Nursing during birth to 12 months||Intake of human milk
Several resources are available that illustrate food exposure scenarios.