PNNL-SA-32285

Written by: Dennis Strenge

Prepared for the U.S. Department of Energy

Pacific Northwest National Laboratory
Operated by the U.S. Department of Energy
By Battelle




Requirements for the MEPAS Intake Module

1.0 Introduction

This document describes the requirements for the Multimedia Environmental Pollutant Assessment System (MEPAS) intake module. The module is specifically designed for inclusion in the Framework for Risk Analysis in Multimedia Environmental Systems (FRAMES), which is a platform that allows for the linking of various multimedia modules into complete source/transport/exposure assessment systems (Whelan et al. 1997). These requirements can be used by software engineers and testers to ensure this module meets the needs of the clients and users.

2.0 Purpose of the MEPAS Intake Module

For all but the external radiation exposure pathways, the MEPAS intake module calculates chemical and radionuclide intakes for individuals at the point of exposure or contact with contaminated media (e.g., water, soil, air, food crops, meat, or milk). For the external radiation exposure to soil or water pathways, the exposure medium concentration is computed and output.  For the external radiation exposure to outdoor air, the output is dependent on the input information provided in the ATO file.  If dose equivalence is input then dose equivalent is output, otherwise, air concentration is output.. Table 1 shows the exposure pathways addressed by this module as a function of the transport media. The module receives input data from exposure modules, as well as data supplied by the user through a module user interface (MUI). The average contaminant intakes (or exposure medium concentrations and dose equivalence for the external radiation pathways) are supplied to receptor health impact modules, or can serve as the endpoint of the simulation.

3.0 Summary of Requirements for the MEPAS Intake Module

This section provides an overall summary of the requirements for the MEPAS intake module. Detailed input, output, and scientific requirements are described in sections 4.0, 5.0, and 6.0 respectively.

The MEPAS intake module will:

Table 1. MEPAS Intake Module Exposure Pathways for Each Transport Medium

Exposure Pathway
Transport or Source Medium
 GroundWater   SurfaceWater   Atmosphere    Soil  
Ingestion of drinking water Yes Yes No No
Dermal contact with water while showering Yes Yes No No
Inadvertent ingestion of water while showering Yes Yes No No
Ingestion of leafy vegetables Yes Yes Yes Yes
Ingestion of other vegetables Yes Yes Yes Yes
Ingestion of meat Yes Yes Yes Yes
Ingestion of milk Yes Yes Yes Yes
Ingestion of fin fish No Yes No No
Ingestion of shellfish No Yes No No
Inadvertent ingestion of water while swimming No Yes No No
Dermal contact with water while swimming No Yes No No
Dermal contact with sediment during shoreline use No Yes No No
Inadvertent ingestion of sediment during shoreline use No Yes No No
Inadvertent ingestion of soil No No Yes Yes
Dermal contact with soil No No Yes Yes
Indoor inhalation of volatile chemicals released from shower water Yes Yes No No
Indoor inhalation of volatile chemicals released from other domestic water uses Yes Yes No No
Inhalation of outdoor air from a passing plume No No Yes No
Inhalation of resuspended soil particles No No Yes Yes
External exposure to radionuclides while swimming No Yes No No
External exposure to radionuclides while boating No Yes No No
External exposure to radionuclides in sediment during shoreline use No Yes No No
External exposure to radionuclides in soil No No Yes Yes
External exposure to radionuclides in outdoor air from a passing plume No No Yes No

4.0 Input Requirements for the MEPAS Intake Module

Data needed to compute intake rates (or to output exposure medium concentrations or dose equivalence for the external radiation pathways) are obtained from two sources. The boundary conditions (i.e., contaminant concentrations in the exposure medium) are obtained from the previous module in the scenario (i.e., an exposure module). Media intake rates (e.g., drinking water ingestion rate, air inhalation rate, etc.) and other receptor characteristics are obtained from the user through the MUI. The boundary conditions are communicated to the module through the Exposure Pathway File (EPF). The input data supplied through the MUI is communicated to the model through the Global Input Data (GID) file and the model pre-processor.

There are some general requirements associated with the MUI, which are:

The MUI must also allow the user to input the following data to define the exposure scenario:

The following data are obtained from the EPF by the MEPAS intake module, and are required for the module to perform its computations:

The MUI must allow the user to define additional parameters that are needed in the analysis. These parameters are identified in the following requirements:

5.0 Output Requirements for the MEPAS Intake Module

The MEPAS intake module is required to produce a Receptor Intake File (RIF) that contains time-varying, average radiation dose equivalence for the external radiation exposure to outdoor air pathway (if input is in terms of radiation dose, otherwise output is in terms of concentration), exposure medium concentrations for the other external radiation exposure pathways, or chemical and radionuclide intake rates for the remaining exposure pathways in Table 1, in accordance with the FRAMES data file specifications. The module also is required to produce a list file (*.RLS file) in ASCII format that documents the data actually read in by the model and provides a summary of intermediate calculation results such as summary intake factors. The data output to the RIF includes radiation dose equivalence for the external radiation exposure to outdoor air pathway, exposure medium concentration for the other external radiation exposure pathways, and chemical and radionuclide intake rates for the remaining exposure pathways in Table 1, for each exposure duration time period, constituent (including progeny), and exposure location. Multiple exposure locations are allowed only for the atmospheric transport analysis.

6.0 Scientific Requirements for the MEPAS Intake Module

The scope of the intake analysis is determined by the modules that are connected to the exposure module (e.g., atmospheric transport or groundwater), and by the selections the user makes in the intake module MUI. The scientific formulations for this module are provided in Strenge and Chamberlain (1995).

Scientific requirements for the intake module are

7.0 References

Strenge, D. L. and P. J. Chamberlain II. 1995. Multimedia Environmental Pollutant Assessment System (MEPAS): Exposure Pathway and Human Health Impact Assessment Models. PNL-10523. Pacific Northwest Laboratory, Richland, Washington.

Whelan G., K. J. Castleton, J. W. Buck, G. M. Gelston, B. L. Hoopes, M. A. Pelton, D. L. Strenge, and R. N Kickert. 1997. Concepts of a Framework for Risk Analysis in Multimedia Environmental Systems (FRAMES). PNNL-11748, Pacific Northwest National Laboratory, Richland, Washington.