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Model Report

Dietary Exposure Potential Model

Last Revision Date: 11/16/2009 View as PDF
General Information Back to Top
Model Abbreviated Name:

DEPM
Model Extended Name:

Dietary Exposure Potential Model
Model Overview/Abstract:
Existing food consumption and contaminant residue databases, typically products of nutrition and regulatory monitoring, contain useful information to characterize dietary intake of environmental chemicals. A PC-based model with resident database system, termed the Dietary Exposure Potential Model (DEPM), correlates extant food information in a format for estimating daily dietary exposure and identifying sources. Though not intended for risk analysis, DEPM is a suitable tool for designing and interpreting exposure measurements, identifying data gaps and establishing priorities for dietary exposure research. DEPM has been used to design exposure measurement studies by estimating the importance of diet relative to other exposure pathways. The potential for high exposure of certain populations, caused by above normal consumption of a particular food, a highly contaminated food, or unique dietary characteristics, is useful information when designing exposure studies or interpreting measurements of contaminants in composited diet samples.

The current version of the DEPM (V5.0) has evolved from a process that inventoried available food consumption and food residue databases and integrated them in a format conducive for dietary exposure modeling. Numerous enhancements to previous versions (V2.3, 1996; V3.3.2, 2000 and V4.0, 2002) have been incorporated based on feedback received from reviewers and new and updated resident databases have been included as they became available.

Keywords: Residue, consumption, dietary exposure, pesticides, metals
Model Technical Contact Information:
Lisa Jo Melnyk, Ph.D.
ORD/NERL/MCEARD/CERB
Melnyk.lisa@epa.gov
513-569-7494
Model Homepage: http://www.epa.gov/nerlcwww/cerb.htm

User Information Back to Top
Technical Requirements
Computer Hardware
Minimum PC: Pentium III; requires approx. 95 megabytes of hard disk space
Compatible Operating Systems
Windows 95, 98, or later
Other Software Required to Run the Model
Visual FoxPro application program.
Download Information
Available for download at: http://www.epa.gov/nerlcwww/cerb.htm
Using the Model
Basic Model Inputs
The DEPM resident database system includes several national, government-sponsored food intake surveys and chemical residue monitoring programs. A unique feature of the DEPM is the use of recipes developed specifically for exposure analysis that link consumption survey data for prepared foods to the chemical residue information, which is normally reported for raw food ingredients, to estimate daily dietary exposure. Consumption in the model is based on 11 food groups containing approximately 800 exposure core food types, established from over 6500 common food items. The summary databases are aggregated in a fashion to allow analyst selection of demographic factors, such age/sex groups, geographical regions, ethnic groups and economic status. The following schematic demonstrates the use of DEPM.

Solid boxes indicate the required input selections and output functions for a typical exposure estimate. Dashed boxes indicate several optional functions available for custom analyses including:

  • An integrated COMBINE tool, which allows the user to combine residue data from multiple residue databases for specified chemicals and foods;

  • A FIAS module to import daily food diaries created by the user from Food Intake Analysis System (FIAS; University of Texas, Human Nutrition Center) software designed for automatic coding of food diary items into USDA's Continuing Survey of Food Intakes by Individuals (CSFII) coding structure.

  • A USER-DEFINED DATA tool, which allows the user to incorporate foods or chemicals, and their residues and consumption data, that are not included in the resident databases;

  • A TAP WATER option, which allows the user to estimate the contribution of tap water to daily dietary exposure.

Basic Model Outputs
Daily intake of residues are estimated for over 300 pesticides and environmental contaminants. In addition, contributions to total exposure from exposure core food groups and individual exposure core foods can also be estimated. The user may rank the exposure estimates by food code, food consumption, food residue or food?s contribution to total daily exposure.

User Support
User's Guide Available?
DEPM is internally documented through the use of HELP screens. A supplemental CD (available by request from the contact listed above) contains documentation related to the development of the model and data included in the resident databases. An abstract is also available from: www.epa.gov/nerlcwww/depm.htm
User Qualifications
User needs only moderate level of technical education and/or modeling experience, including general knowledge of dietary exposure and PC use.

Model Science Back to Top
Problem Identification
Daily dietary exposure to environmental contaminants can be estimated from extant data on food consumption and residues.
Summary of Model Structure and Methods
Included in supplemental documentation.
Model Evaluation
Many checks and balances during development of model
User comments
Uses publicly available databases

Moderate model testing (evaluation) has been performed both internally and outside USEPA.

Model has been internally peer reviewed.

There was extensive QC of resident databases to source data.

Continuing evaluation and testing is needed to determine how DEPM V5.0 can be further improved and enhanced to meet the needs of both USEPA and others of the human exposure research community.

DEPM was developed for U.S. EPA by Exponent (formerly Novigen Sciences, Inc.) and Environ Corp.

Case Studies
Tomerlin et al. JEAEE, 1997


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