EPA-Expo-Box (A Toolbox for Exposure Assessors)
- Fate & Transport
- Calculation Tools
Food crops could be exposed to pollutants that are present in ambient air, soil, or water. Other sources of chemical contaminants in food crops include pesticides and other agrochemicals (e.g., fertilizers). Food products might also be exposed to contamination while being harvested, transported, stored, packaged, processed, and prepared. Contaminants in breast milk of lactating mothers may be present because mothers themselves are exposed—see Sources and Fate and Transport in this module. Some persistent environmental contaminants that tend to accumulate in animal fats are frequently found in meat, poultry, fish, and dairy products (including breast milk). Other contaminants (e.g., perchlorate and a variety of pesticides) might be found in fruits, vegetables, and other agricultural commodities. Information about food safety programs at EPA and other federal agencies is available at: http://www.epa.gov/agriculture/tfsy.html#pesticideinfood.
Information on contaminant concentrations in food is needed to assess exposure via the food ingestion route. Characterizing contaminant concentrations for an exposure scenario is typically accomplished using some combination of the following approaches:
- Sampling the bulk foods that the receptor is expected to ingest and analyzing them to measure contaminant concentrations
- Modeling the contaminant concentrations based on environmental media concentrations and bioconcentration or biotransfer factors
- Using existing, available measured concentration data collected for related analysis or compiled in databases
EPA-Expo-Box provides information on measuring or modeling contaminant concentrations in food and on available food measurement data that might be useful in estimating exposures. The concentrations of contaminants in food may be measured using sampling and analytical methods designed to support such measurements (see Measuring Concentrations below). In the absence of monitoring data, a variety of models can be used to estimate contaminant concentrations in food.
Methods for measuring concentrations of chemical contaminants in food may include methods required for specific chemicals or groups of chemicals that are regulated by EPA or methods for unregulated chemicals or groups of chemicals of interest.
In the absence of measurement data, the concentrations of contaminants in food may be estimated based on modeling. Typically, concentrations in foods are modeled using BCFs or BTFs as described in the Fate and Transport pages of this module. A number of resources are available to assist in these modeling efforts.
The U.S. Department of Agriculture and U.S. Food and Drug Administration have established food safety programs to monitor for potential contaminants in the food supply. EPA also conducts sampling and analysis of milk and other media to monitor for radiation. Food products have also been analyzed as part of special studies conducted by EPA (e.g., Total Exposure Assessment Methodology [TEAM] studies). Resources for obtaining available measurement data are summarized in the table below.