Exposure and Fate Assessment Screening Tool (E-FAST) Version 2.0 Documentation Manual


Exposure and Fate Assessment
Screening Tool (E-FAST)
Version 2.0
Documentation Manual
Prepared for:
U.S. Environmental Protection Agency
Office of Pollution Prevention and Toxics
Exposure Assessment Branch
Prepared by:
Versar, Inc.
6850 Versar Center
Springfield, VA 22151
EPA Contract No. EP-W-04-035
October, 2007

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ACKNOWLEDGMENTS AND DISCLAIMER
Versar, Inc. (under Contract No. EP-W-04-035) prepared this report with the direction and review
of the Office of Pollution Prevention and Toxics. Neither the United States Government nor any of its
employees, contractors, subcontractors, or their employees make any warranty, expressed or implied, or
assume any legal liability or responsibility for any third party's use of or the results of such use of any
information, apparatus, product, or process discussed in this report, or represent that its use by such party
would not infringe on privately owned rights.
All chemical names, physical-chemical properties, and chemical release information presented
within this document are fictional and bear no relation to any real chemical or industry. Facility names
and locations presented in the example screens were chosen at random from the databases used by the
various models, and are not involved in any way with the development of the models.
ACKNOWLEDGMENTS AND DISCLAIMER
To comply with the accessibility requirements of Section 508 of the Rehabilitation Act
Amendments, the text, Figures, Tables, and Equations in this Manual are now accessible via the assistive
technology reader.

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TABLE OF CONTENTS
1.0 INTRODUCTION 	1-1
1.1	Installing E-FAST V2.0	1-2
1.2	Running E-FAST V2.0 	1-5
1.3	Saving, Printing, and Revising E-FAST V2.0 Results 	1-7
1.3.1	Saving Results	1-7
1.3.2	Printing Results	1-8
1.3.3	Revising Results 	1-8
2.0 PHYSICAL-CHEMICAL PROPERTIES AND FATE 	2-1
3.0 MODELS FOR SCREENING-LEVEL EXPOSURE ESTIMATES 	3-1
3.1	General Population and Ecological Exposure from Industrial Releases 	3-3
3.1.1	Release Information Page	3-3
3.1.1.1	Surface Water Releases	3-6
3.1.1.2	Landfill Releases 	3-10
3.1.1.3	Ambient Air Releases	3-10
3.1.2	Exposure Factors Page 	3-13
3.1.3	Environmental Release Results Page 	3-18
3.1.4	Rivers Results Page	3-18
3.1.4.1	Rivers Results Page - General Site Information	3-20
3.1.4.2	Rivers Results Page - Drinking Water Information 	3-22
3.1.4.3	Rivers Results Page - Fish Ingestion Information 	3-24
3.1.4.4	Rivers Results Page - Endangered Species	3-26
3.1.5	SIC Code Results Page	3-27
3.1.5.1	SIC Code Results Page - General SIC Code Information	3-29
3.1.5.2	SIC Code Results Page - Drinking Water Information	3-30
3.1.5.3	SIC Code Results Page - Fish Ingestion Information	3-31
3.1.6	Lakes Results Page	3-32
3.1.6.1	Lakes Results Page - General Lake Information	3-33
3.1.6.2	Lakes Results Page - Fish Ingestion Information	3-34
3.1.6.3	Lakes Results Page - Endangered Species 	3-36
3.1.7	Landfill Results Page 	3-36
3.1.8	Inhalation Results Page	3-40
3.1.8.1	Inhalation Results Page - Inhalation Exposure Estimates 	3-41
3.1.8.2	Inhalation Results Page - Release Information	3-48
3.1.8.3	Inhalation Results Page - Meteorological/Terrain andDownwash
Information 	3-49
3.1.8.4	Inhalation Results Page - SCREEN3Model Results	3-50
3.1.9	PDM Site-Specific Results Page	3-51
3.1.10	PDM SIC Code Results Page 	3-54
3.2	Do wn-the-Drain	3-57
3.2.1	Consumer Disposal Inputs Page	3-57
3.2.2	Disposal Results Page	3-58
3.2.2.1	Disposal Results Page - Concentrations	3-60
3.2.2.2	Disposal Results Page - PDM Information	3-61
3.2.2.3	Disposal Results Page - Drinking Water Information 	3-63
3.2.2.4	Disposal Results Page - Fish Ingestion Information 	3-66

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TABLE OF CONTENTS (Continued)
3.3	Consumer Exposure Module (CEM)	3-69
3.3.1	Introduction Page 	3-69
3.3.2	Scenario Page 	3-70
3.3.2.1	Generic Consumer Product Scenarios	3-71
3.3.2.2	User-Defined Scenario	3-76
3.3.2.3	Exposed Population	3-78
3.3.3	Inhalation Input Page 	3-78
3.3.4	Day of Use Input Page 	3-80
3.3.5	Days After Use (Non-Use Days) Input Page 	3-81
3.3.6	Dermal Input Page 	3-82
3.3.7	Estimation of Indoor Air Concentrations 	3-85
3.3.7.1	Pollutant Mass Balance 	3-86
3.3.7.2	Air Mass Balance	3-86
3.3.8	Estimation of Consumer Exposures 	3-90
3.3.8.1	Estimation of Inhalation Exposures	3-92
3.3.8.2	Estimation of Dermal Exposures	3-95
3.4	Probabilistic Dilution Model (Stand-alone PDM)	3-97
3.4.1	PDM Site-Specific Page	3-98
3.4.2	PDM SIC Code Results Page 	3-100
4.0 REFERENCES	4-1
Appendix A Definitions for Physical-Chemical/Fate Properties 	 A-l
Appendix B Surface Water Discharge Information Organization and Sources	 B-l
Appendix C Statistical Framework of Probabilistic Dilution Model (PDM)	 C-l
Appendix D Issues Pertaining to Inhalation Exposure Estimation Conducted in CEM	 D-l
LIST OF TABLES
Table 2-1. Physical-Chemical Properties Required for Modeling in E-FAST V2.0	2-2
Table 3-1. Default Values for Select Input Parameters to SCREEN3 	3-12
Table 3-2. Default Exposure Parameter Values Used in E-FAST V2.0	3-15
Table 3-3. Default Surface Area/Body Weight (SA/BW) Ratios Used in CEM Module for
Bar Soap 	3-74
LIST OF FIGURES
Figure 1-1. E-FAST V2.0 Welcome Screen	1-3
Figure 1-2. Customer Information Screen 	1-3
Figure 1-3. Destination Folder Screen 	1-4
Figure 1-4. Ready to Install Screen	1-4
Figure 1-5. Installing EFAST2 Screen 	1-5
Figure 1-6. Installation Completed Screen	1-5
Figure 1-7. E-FAST V2.0 Introductory Screen	1-6
Figure 1-8. E-FAST V2.0 Model Schematic 	1-6
Figure 1-9. Change the Data Drive Screen	1-8

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LIST OF FIGURES (Continued)
Figure 2-1. PChem/Fate Inputs Screen 2-1
Figure 3-1. Screening Level Main Page 3-1
Figure 3-2. General Release Information Page 3-4
Figure 3-2a. General Release Information Page - Surface Water 3-5
Figure 3-2b. General Release Information Page - Landfill 3-5
Figure 3-2c. General Release Information Page - Ambient Air 3-6
Figure 3-3. Select a Facility Screen 3-8
Figure 3-4. Select an SIC Code Screen 3-10
Figure 3-5. SCREEN3 - Release Information 3-11
Figure 3-6. SCREEN3 - Meteorological and Terrain Information 3-12
Figure 3-7. SCREEN3 - Downwash Information 3-13
Figure 3-8. Exposure Factors Page 3-14
Figure 3-9. Environmental Release Results Page 3-18
Figure 3-10. Rivers Results Page - Aquatic Exposure Estimates - Surface Water 3-20
Figure 3-11. Rivers Results Page - Drinking Water Exposure Estimates 3-23
Figure 3-12. Rivers Results Page - Fish Ingestion Exposure Estimates 3-25
Figure 3-13. Rivers Results Page - Endangered Species 3-27
Figure 3-14. SIC Code Results Page - Aquatic Exposure Estimates - Surface Water 3-28
Figure 3-15. SIC Code Results Page - Drinking Water Exposure Estimates 3-30
Figure 3-16. SIC Code Results Page - Fish Ingestion Exposure Estimates 3-31
Figure 3-17. Lakes Results Page - Dilution Factors and Water Concentrations 3-33
Figure 3-18. Lakes Results Page - Fish Ingestion Exposure Estimates 3-35
Figure 3-19. Landfill Results Page - Landfill Exposure Estimates 3-37
Figure 3-20. Inhalation Results Page - Inhalation Exposure Estimates 3-41
Figure 3-21. Inhalation Results Page - Release Information 3-49
Figure 3-22. Inhalation Results Page - Meteorological/Terrain and Downwash Information 3-50
Figure 3-23. Inhalation Results Page - SCREEN3 Model Results 3-51
Figure 3-24. PDM Site-Specific Results Page 3-52
Figure 3-25. PDM SIC Code Results Page 3-55
Figure 3-26. Consumer Disposal Inputs Page - Selecting PDM 3-58
Figure 3-27. Disposal Results Page - Aquatic Exposure Estimates - Surface Water 3-59
Figure 3-28. Disposal Results Page - PDM Disposal Exposure Estimates 3-62
Figure 3-29. Disposal Results Page - Drinking Water Exposure Estimates 3-64
Figure 3-30. Disposal Results Page - Fish Ingestion Exposure Estimates 3-66
Figure 3-31. CEM Introduction Page 3-70
Figure 3-32. Scenario Page 3-71
Figure 3-33. User-Defined Scenario Description Screen 3-76
Figure 3-34. Inhalation Input Page 3-79
Figure 3-35. Day of Use Input Page 3-80
Figure 3-36. Days After Use (Non-Use Days) Input Page 3-82
Figure 3-37. Dermal Input Page 3-83
Figure 3-38. CEM Inputs 3-90
Figure 3-39. CEM Inhalation Exposure Estimates 3-91
Figure 3-40. CEM Dermal Exposure Estimates 3-91
Figure 3-41. PDM Site-Specific Results Page (Stand-alone) 3-97
Figure 3-42. PDM SIC Code Results Page (Stand-alone) 3-100

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1.0 INTRODUCTION
The Exposure and Fate Assessment Screening Tool, Version 2.0, also known as E-FAST V2.0, is
a screening-level computer tool that allows users to estimate chemical concentrations in water to which
aquatic life may be exposed, as well as generate human inhalation, drinking water ingestion, and fish
ingestion exposures resulting from chemical releases to air, water, and land. In addition, E-FAST V2.0
identifies endangered species in the vicinity of releases at known locations—"site-specific" releases. E-
FAST V2.0 also may be used to assess inhalation and dermal exposures to chemicals that may result from
the use of certain types of consumer products. The exposed populations assessed by the model are either
some segment of the general population or consumers. Worker exposures are not assessed in this model.
The exposure scenarios in E-FAST V2.0 contain default exposure parameter values that allow the
exposures to be estimated with minimal data entry. Because E-FAST V2.0 incorporates defaults of either
a combination of upper percentile and mean exposure parametric values or all upper percentile parametric
values, the exposure/dose estimates are considered to be high-end estimates.
E-FAST V2.0 was developed to support U.S. Environmental Protection Agency (EPA)
assessments of potential exposures to chemicals. Screening-level models are rarely if ever used as the sole
justification for regulatory decision-making at EPA. Additional data and more rigorous tools are used to
improve the estimates of exposures and risks for such decisions. Thus, the model's results may not
accurately reflect all of the information and data used by EPA to make a regulatory decision on a
chemical.
When Should I Use the Model?
E-FAST V2.0 is appropriate for use as a screening tool to assess potential exposures from
chemical discharges to air (stack or fugitive releases), surface water, or land. E-FAST V2.0 can also be
used to estimate potential inhalation and dermal exposures to consumer products, such as hard surface
cleaners, soaps, air fresheners, paints, gasoline, and motor oil.
When Is It Not Appropriate To Use the Model?
E-FAST V2.0 is characterized by EPA as a "screening model." Screening model results are
intended to be conservative, meaning that predicted concentrations and exposures are likely to be at the
high end of or higher than concentrations that might actually be occurring in a real-world setting. If an
exposure estimated by a screening model results in an unacceptably high health risk, then an appropriate
next step in the assessment process would be to refine the parameter input or perform the assessment with
different and perhaps more complex models. Another response might be to consider monitoring to gather
actual emissions data that can be used to estimate exposure.
E-FAST V2.0 does not estimate physical-chemical properties, environmental fate parameters, or
environmental releases. If measured physical-chemical and environmental fate data do not exist, software
available from EPA or commercially available estimation software can be used to estimate these
properties. The exposures estimated by E-FAST V2.0 reflect the amounts of chemical inhaled, ingested,
or on the surface of the skin. In general, E-FAST V2.0 does not estimate chemical absorption; however,
the Consumer Exposure Module (CEM) (See Section 3.3) does contain the option to estimate an absorbed
dermal dose if permeability coefficient data are available.
1-1

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How Does E-FAST V2.0 Relate to Previous Versions of E-FAST Developed by OPPT?
E-FAST V2.0 replaces E-FAST beta and incorporates revisions based on internal and external
peer review. Revisions include an update of data sources, enhanced programming capabilities, and
improved user-friendliness, including an option to save in Corel® WordPerfect or Microsoft® Word
formats.
Potential Average Daily Dose (ADDP0T) and Average Daily Concentration (ADCP0T) values are
not estimated in E-FAST V2.0 because averaging times for non-cancer chronic or subchronic effects vary
by effect. In these cases, it is suggested that the averaging times should be determined on a case-by-case
basis via communication between the exposure assessor and hazard assessor. When the appropriate
averaging times have been determined, potential ADD and ADC values may be estimated by substituting
those averaging times for the lifetime averaging time in the potential Lifetime Average Daily Dose
(LADDpoi) and Lifetime Average Daily Concentration (LADCP0T) equations.
E-FAST V2.0 March 2007 differs from E-FAST V2.0 April 2006 in that an error in the
landfill calculation was corrected - this correction is reflected in Figure 3-19. E-FAST V2.0
October 2007 differs from E-FAST V2.0 March 2007 in that source code that caused model
failure under unusual input circumstances was corrected.
How Do I Get Started Using E-FAST V2.0?
To run E-FAST V2.0, your computer system should meet the following requirements:
An IBM-compatible computer with a Pentium processor or higher
Windows 95 or higher operating system
• 32 MB or higher of RAM (64 MB recommended)
85 MB of hard disk space
Also, E-FAST V2.0 was designed for a computer monitor with a minimum 800 x 600 screen resolution
for maximum user-friendliness.
1.1 Installing E-FAST V2.0
To install E-FAST V2.0, download the installation file from EPA's Office of Pollution
Prevention and Toxics (OPPT) website (http://www .epa.gov/oppt/exposure'). After downloading is
complete, run the installation program (self-extracting zip file). The install program begins with a
window that indicates that the computer is performing certain functions such as checking, configuring,
and preparing to install E-FAST V2.0. This screen requires no user input. In the E-FAST V2.0 Welcome
screen (shown in Figure 1-1), select "Next" to display the Customer Information screen and enter your
user name and the company name (Figure 1-2). After you have entered this information, click on "Next"
to continue.
1-2

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1 j$ EFAST2 - InstallShield Wizard

Welcome to the InstallShield Wizard for
EFAST2

The InstallShield(R) Wizard will install EFAST2 on your
computer. To continue, click Next.

WARNING: This program is protected by copyright law and
international treaties.



| Next > | Cancel
Figure 1-1. E-FAST V2.0 Welcome Screen
0 EFAST2 - InstallShield Wizard
Customer Information
Please enter your information.
User Name:
|Employee-010376
Organization:
|Versar, Inc.
ir^allSfiielcl'-
< Back
Cancel j
Figure 1-2. Customer Information Screen
The next screen, Destination Folder (Figure 1-3), allows you to install the program under the
default directory shown on the screen or in another directory. If you wish to install E-FAST V2.0 in the
default directory, and your computer already contains a directory named C:\Program Files\EFAST2, it
should be removed or renamed prior to installing E-FAST V2.0. To install E-FAST V2.0 in a different
directory, click the "Browse" button and select the desired directory and path, then select "Next." Note
that the name of the Program Folder in the Windows® Start Menu will be "EFAST 2.0" and cannot be
changed during the installation of the model.
1-3

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j ,v- EFAST2 - InstallShield Wizard
Destination Folder
Click Next to install to this folder, or click Change to install to a different folder.
Install EFAST2 to:
c:\Program Files\EFAST2\
Change,
ih^fSfteld	
< Back | f Next > j| Cancel |
Figure 1-3. Destination Folder Screen
E-FAST V2.0 is ready to install the program files on your computer. Figure 1-4 shows the
information you have entered so far. If you need to modify anything, click on the "Back" button to make
the necessary changes. Otherwise, click 011 the "Install" button to begin the installation. The Installing
EFAST2 screen, shown in Figure 1-5, will automatically disappear once the necessary files have been
installed.
I j|3 EFAST2 - InstallShield Wizard
cl
Ready to Install the Program
is

The wizard is ready to begin installation.
M
If you want to review or change any of your installation settings, click Back. Click Cancel to
exit the wizard.
Current Settings:

Setup Type:


Destination Folder:


c:\Program Files\EFAST2\


User Information:


Name: Employee-010376


Company: Versar, Inc.



< Back. | nstall | Cancel

Figure 1-4. Ready to Install Screen
1-4

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j f? EFAST2 - InstallShield Wizard
Installing EFAST2
The program features you selected are being installed.
Q] Please wait while the InstallShield Wizard installs EFAST2. This may take
several minutes.
Status:
Copying new files
ire* gnshreld -
[text >:¦ [	Cancel
Figure 1-5. Installing EFAST2 Screen
ftjjr EFAST2 - InstallShield Wizard
1*1
InstallShield Wizard Completed
The InstallShield Wizard has successfully installed EFAST2. Click
Finish to exit the wizard.
Figure 1-6. Installation Completed Screen
Figure 1-6 shows the final screen for the E-FAST V2.0 installation program. Click on the
"Finish" button to complete the process.
1.2 Running E-FAST V2.0
After installing E-FAST V2.0, open it by clicking on the "Start" button on the Windows taskbar
at the bottom of the screen and selecting the E-FAST V2.0 under the Programs listing. The E-FAST V2.0
Introductory screen (Figure 1-7) shows E-FAST V2.0"s three major components, which are accessible
from the E-FAST V2.0 Introductory screen. Figure 1-8 shows a schematic of how each component
interacts with the numerous models E-FAST V2.0 uses to calculate exposure.
1-5

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E-FAST V 2.0 Introductory Screen
Change Data Drive Help Quit
E-FAST2
Exposure and Fate Assessment Screening Tool
M-lal"
7 Help
*7 About
SEPA
Environmental Protection Agency
g$ Select a Chemical ID and modify its physical-chemical and fate properties before continuing to any module
Models for
Screening-Level
Exposure Estimates
R

r
Report Generator
if
Figure 1-7. E-FAST V2.0 Introductory Screen
Landfill
Ambient Air
(SCREEN3)
Surface
Water
Consumer
Exposure
Pathway
Down-the-Drain
Probabilistic
Dilution
Model
(PDM)
Report Generator
Component
(under construction)
Models for
Screening-Level
Exposure Estimates
Component
General Population
and Ecological
Exposure fiom
Industrial Releases
Physical-Chemical Properties and Fate
Component: (Select a Chemical ID Button)
Figure 1-8. E-FAST V2.0 Model Schematic
1-6

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The three components that make up E-FAST V2.0 are briefly described below:
1. Physical-Chemical Properties and Fate Component. This component of E-FAST V2.0 defines
the physical-chemical properties you will need for use with the other modeling components. You
cannot access the other components of E-FAST V2.0 without first going to this component. To
access it, click on the bar, "Select a Chemical ID and modify its physical-chemical and fate
properties before continuing to any module" on the E-FAST V2.0 Introductory screen. This will
take you to the PChem/Fate Inputs screen (Figure 2-1), where the program will define the
physical-chemical properties needed for the other modeling modules. See Section 2.0 for a more
detailed description of this model component. After filling in the required information and
clicking on "Select This Chemical ID," you will be returned to the E-FAST V2.0 Introductory
screen, where you may select another model component.
2. Models for Screening-Level Exposure Estimates Component. This component provides
modeled, screening-level estimates of the concentrations and the potential doses of chemicals
released to air, surface water, and landfills, and from consumer products. The estimates are
designed to be conservative (i.e., to use high-end estimates of exposure or even to overestimate
exposure). A detailed description of the exposure and fate modeling process is presented in
Section 3.0.
3. Report Generator Component. A future capability of E-FAST V2.0 will be the addition of an
exposure summary report generator. EPA envisions that the report generator would assist the
assessor in completing summary exposure reporting formats such as the formats that are currently
under development within the Organization for Economic Cooperation and Development
(OECD). If the assessor had monitoring data for an exposure scenario (EPA's preference), the
report generator would prompt the user for an exposure estimate based upon that data as well as
other relevant information associated with the monitoring data (e.g., the objective of the
monitoring study, a brief description of the study design, etc.). If the assessor did not have
monitoring data, the report generator would be linked to the E-FAST V2.0 exposure models and
many of the exposure summary report entries would be filled in by E-FAST V2.0.
E-FAST V2.0 also provides on-screen guidance to assist users with questions they may have
while running the model. You can access the on-screen guidance by clicking on the "Help" button found
on most data entry screens.
1.3 Saving. Printing, and Revising E-FAST V2.0 Results
1.3.1 Saving Results
The Change Data Drive menu at the upper left-hand corner of the Introductory screen
(Figure 1-7) allows you to change the directory to which model results are saved. By default, results are
written to C:\Program Files\EFAST2\results. To change this directory, click on the bar "Change the Data
Drive." A pop-up window (Figure 1-9) will guide you through the process of selecting a new directory.
Click on Save changes to save the new directory.
1-7

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Change the Data Drive
3gT>
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2.0 PHYSICAL-CHEMICAL PROPERTIES AND FATE
The PChem/Fate Inputs screen (Figure 2-1) prompts you to select the desired modeling modules
and Chemical ID (e.g., CAS number) for the chemical of interest. Note that only one chemical of interest
may be selected for each model run. The Chemical ID will be used throughout the execution of the
E-FAST V2.0 program. The modeling modules you can select include General Population and
Ecological Exposure from Industrial Releases, including surface water, landfill, and ambient air releases;
Down-the-Drain; Consumer Exposure Pathway; and the Probabilistic Dilution Model (PDM). The
Chemical ID combination list box contains a list of all Chemical IDs that have been entered since the
model was first installed. You may select one of these Chemical IDs or enter a new ID by typing it into
the combination list box. If you select a pre-existing ID, E-FAST V2.0 will fill in the properties that were
used the last time that Chemical ID was modeled. Otherwise, the fields for physical-chemical properties
and fate will be blank.
0 PChem/Fate
*7 Help
PChem/Fate Inputs Screen
General Population and
Ecological Exposure
From Industrial Releases
P? Surface Water
p7 Landfill
W Ambient Air
W Down-the-Drain
W Consumer Exposure Pathway
P7 Probabilistic Dilution Model (PDM)
Chemical ID:
Chemical Name:
Bioconcentration Factor:
Wastewater Treatment Removal:
Adsorption to Wastewater Treatment Sludge:
Drinking Water Treatment Removal:
Groundwater Migration Descriptor:
Fugitive Air Emissions Removal:
Stack Air Emissions Removal:
Consumer Product Weight Fraction (central tendency):
Consumer Product Weight Fraction (high end):
Molecular Weight:
Vapor Pressure:
~3
30.00 (~ No BCF available?
25.00 %
11.00 X
9.00 %

20.00 X
90.00 X
222.00 g/mole
4.00E-03 |torr(mmHg) H
if Select This Chemical ID
Figure 2-1. PChem/Fate Inputs Screen
After selecting a Chemical ID or entering a new one, you may select the media and the exposure
pathway you wish to model by clicking on the appropriate checkboxes on the left-hand side of the screen.
The fields that appear at the center of the screen depend on the status of the checkboxes; you will only be
prompted for physical-chemical properties that are required for the models you have chosen to ran.
Depending on the modules you selected, you must enter some or all of the following relevant physical-
chemical properties, in the appropriate units and in the adjacent blanks on the screen: the bioconcentration
factor (BCF) of the chemical, if known (unitless); the wastewater treatment removal percentage for the
chemical (%); the adsorption in wastewater treatment of the chemical to sludge (%); the drinking water
treatment removal percentage for the chemical (%); the groundwater migration descriptor of the chemical
(unitless); the removal rates for fugitive and stack air emissions (%); the weight fraction of the chemical
in consumer products (Central Tendency and High-End - e.g., median and 90th percentile, respectively);
the molecular weight of the chemical (g/mol); and the vapor pressure of the chemical (torr, atm, mb, or
Pa, which you may select from a drop-down list). Definitions of these terms are provided in Appendix A.
2-1
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Table 2-1 shows the available modules and the physical-chemical and fate properties you are asked to
provide.
Table 2-1. Physical-Chemical Properties Required for Modeling in E-FAST V2.0

Surface
Water
Lardffl
Ambient
Air
Etomi
the
Drain
Consumer
Exposure
P&thwajr
Probabilistic
Dilution
Model
(PEM)
Chemical NameJChemical ID
~
~
V
~
V
~
Bioconcentration Factor
~

Wastewater Treatment Removal
~

Adsorption to Wastewater Treatment Sludge

Drinking Water Treatment Removal
~
~

Groundwater Migration Descriptor

Fugitive Air Emissions Removal

Stack Air Emissions Removal

Consumer Product Weight Fraction (Osntral
Tendency

Coreumer Product Weight Fraction (High-End)

Molecular Weight

Vapor Pressure

The model inputs that are requested of you as you move forward through the input screens
depend on which models have been selected on this screen. For example, if you do not mark the Surface
Water checkbox, you will not be prompted to enter surface water releases. For the sake of clarity, the
instructions and screen images in Section 3.0 assume that all six checkboxes are selected. If this is not the
case for you, your input screens will appear slightly different, but the instructions that relate to the models
you are interested in will remain the same.
Once you have put a checkmark beside all desired modules and entered all required values, click
on "Select this Chemical ID" to return to the E-FAST V2.0 Introductory screen (Figure 1-7). You may
now proceed to the Models for Screening-Level Exposure Estimates component of E-FAST V2.0.
2-2
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3.0
MODELS FOR SCREENING-LEVEL EXPOSURE ESTIMATES
After you have selected the Chemical ID for the chemical of interest, you can click on "Models
for Screening-Level Exposure Estimates." The Screening Level Main page will appear (see Figure 3-1).
|^T Screening Level Main Page
E-FAST2
Exposure and Fate Assessment Screening Tool
7 Help |
Select from one of the four modules below:
General Population
and Ecological
Exposure From
Industrial Releases
Down
The
Drain
Consumer
Exposure
Pathway
•
m
H
Probabilistic
Dilution Model
(PDM)
Exposed Population
Adult r Small Child (age 3-5)
C" Youth (age 13-19] C Infant (age 1-2)
C Child (age 6-12) C lnfant(age < 1)
Select Document Report Format

Click here to select

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Figure 3-1. Screening Level Main Page
The Screening Level Main page consists of four exposure assessment modules, which you can
open by clicking on the appropriate button:
General Population and Ecological Exposure from Industrial Releases — addresses human
exposures resulting from facility releases to air, water, and land. Incorporates the Probabilistic
Dilution Model (PDM) to address aquatic and ecological exposures and risks from releases to
water. Also identifies endangered animal species near site-specific water releases. See
Section 3.1.
Down-the-Drain — addresses human and aquatic ecological exposures and risks resulting from
chemical releases in household wastewater. See Section 3.2.
Consumer Exposure Pathway — addresses various consumer exposure pathways (i.e., dermal
and inhalation) using CEM. The model calculates exposure resulting from consumer use. See
Section 3.3.
Probabilistic Dilution Model (PDM) — addresses aquatic ecological exposures and risks. PDM
is used by the General Population and Ecological Exposure from Industrial Releases, and
Down-the-Drain modules to calculate concentrations and to predict the number of days per year a
chemical's concentration of concern (COC) in an ambient water body will be exceeded by the
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discharge from a facility. This module allows the user to run the model independently of the
release scenarios that are used in those modules. See Section 3.4.
In addition to the four modules, this screen contains a box where you may select the exposed population
for which the model will estimate concentrations and exposures. The default selection is for adults, but
the user may also select youths (children 13-19 years), children 6 to 12 years, children 3 to 5 years,
infants 1 to 2 years old, or infants less than one year old. To the right is a box marked "Select Document
Report Format," where you may select the word processing format in which model output files will be
saved. At the bottom of the screen is a button marked "Return to E-FAST2 Main Page," which you may
click if you want to return to the E-FAST V2.0 startup screen.
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3.1
General Population and Ecological Exposure from Industrial Releases
The General Population and Ecological Exposure from Industrial Releases module was developed
by OPPT as a software program to generate estimates of chemical concentrations in surface waters to
which aquatic life may be exposed and estimates of human inhalation, drinking water, and fish ingestion
exposures resulting from chemical releases to water, land, and air.
The General Population and Ecological Exposure from Industrial Releases screen consists of two
pages: the Release Information page and the Exposure Factors page. Each page appears as a tab at the top
of the screen. When you first access this module, only the Release Information page is present. After
entering the required data for all environmental releases, as described below, the Exposure Factors page
appears; the Release Information page is hidden and can be accessed by clicking on the Release
Information tab at the top of the screen.
The following text describes, in outline form, the data entry procedure that is described in this
section:
1. Release Information Page
For each release activity:
• Enter number of sites
• Select and Enter surface water, landfill, and/or ambient air releases
• Click "next release activity" button and repeat above steps until all release activities are
entered
2. Click "Release activities completed..." button
3. Exposure Factors Page
• Enter exposure factors
4. Click "Calculate, save results..." button to run model
3.1.1 Release Information Page
The Release Information page presents three sub-pages labeled "General Release Info," and "Select a
Facility," or "Select an SIC code." The "General Release Info" sub-page is the main page for entering
release data. The other two are secondary pages used to specify a facility or industrial category for surface
water releases, and are discussed in Section 3.1.1.1. On the General Release Information page (Figure 3-
2), you may enter releases to the environment for any number of release activities; a release activity is
defined as an industrial or commercial process that causes a chemical to enter the environment through
the air, surface water, and/or groundwater (i.e., landfill). The tabs for entering this information are
displayed when the appropriate box is selected from the white bar near the middle of the page. The box
in the upper left-hand corner of the page lists all the release activities that have been entered; when you
first encounter this page, there will be one item in this box (the release that you are currently entering). As
you specify additional release activities, they will appear in this box; you may revisit an earlier entry by
clicking once on an item in the list. Below this box is a text field where you may enter an identifying
word or phrase for the release activity (i.e., "Manufacturing" or "Processing"). Below that is a numerical
text field where you must enter the number of sites to which the releases on this page are applicable.
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To develop exposure doses, you must provide the estimated disposal release amounts. To enter
release information, first select the box or boxes located next to Surface Water, Landfill, or Ambient Air
in the white bar on the General Release Information page. For each box you select, a tab displaying the
applicable model inputs will appear (Figures 3-2a, b, and c.). To enter chemical releases, select each tab
in sequence and enter the amount of the release. Note that the units of these releases are on a per site
basis. Each disposal release option has a check box that allows you to omit dose calculations for that
particular release. You may choose this option if you have a release that is below a threshold of concern,
and you would like the release to be reported in the model output even though you do not need dose
calculations. Remarks about any of the releases may be entered in the text field at the lower left-hand
corner of the page. A more detailed description of the entry fields for surface water, landfill, and ambient
air releases may be found in Sections 3.1.1.1, 3.1.1.2, and 3.1.1.3, respectively.
IT" Screening Level Inputs
Release Info Page ||
General Release Info I
Ichem ID/Rel It
Delete selected run
Select the types of releases (surface water, landfill, ambient air).
Next, input the amount of release and number of days/year of release.
For surface water, you must also select a facility or SIC code and
concentrations of concern if required. For ambient air, you must
calculate air concentrations before continuing if selected.
*? Help
| Surface water Landfill J~~ Ambient i
Enter Release Activity Below:
# Sites [l Tj
(ft sites with identical releases)
Next Release Activity |
General Remarks
yf Release activities completed? Continue to Exposure Factors page
Figure 3-2. General Release Information Page
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17' Screening Level Inputs
Release Info Page ]
General Release Info 1 Select a facility |
[Chi
iem ID/Rel tt
Select the types of releases (surface water, landfill, ambient air).
Next, input the amount of release and number of days/year of release.
For surface water, you must also select a facility or SIC code and
concentrations of concern if required. For ambient air, you must
calculate air concentrations before continuing if selected.
9 Help
W Surface water Landfill W Ambient air
\ Delete selected run | Surface Water | Landfill | Ambient Air |
Enter Release Activity Below:
Manufacturing
tt Sites [i J]
(ft sites with identical releases)
jC? Next Release Activity |
General Remarks
This is an active site
|~ No dose calculations required
SW Comment
Release | 40.00 kg/site/day Days per year of Release: | 200 days/yr
Choose facility or SIC code analysis:
Facility NPDES It. name:|"-0024791 |MALPEM STP
r SIC Code Description: |
[7 Include PDM run
Concentration(s) of Concern:
\ (enter up to three values)
10.00
1.00 ug/L
Release activities completed? Continue to Exposure Factors page |
Figure 3-2a. General Release Information Page - Surface Water
U" Screening Level Inputs
Release Info Page |
General Release Into ] Select a facility |
Chen, ID/Rel tt
1
Select the types of releases (surface water, landfill, ambient air).
Next, input the amount of release and number of days/year of release.
For surface water, you must also select a facility or SIC code and
concentrations of concern if required. For ambient air, you must
calculate air concentrations before continuing if selected.
¦7 Help
f? Surface water W Landfill p" Ambient air
Delete selected run | Surface Water Landfill | Ambient Air ]
Enter Release Activity Below:
Manufacturing
ft Sites [l
(ft sites with identical releases)
gCr- Next Release Activity [
General Remarks
f~ |No dose calculationsirequired
Landfill Comment
Non-sludge:
Sludge:
100 kg/site/day | 100 days/yr
kg/site/day | 200 days/yr
V' Release activities completed? Continue to Exposure Factors page
Figure 3-2b. General Release Information Page - Landfill
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17 Screening Level Inputs
Release Info Page |
General Release Info 1 Select a facility |
[chi
iem ID/Rel tt
Select the types of releases (surface water, landfill, ambient air).
Next, input the amount of release and number of days/year of release.
For surface water, you must also select a facility or SIC code and
concentrations of concern if required. For ambient air, you must
calculate air concentrations before continuing if selected.
9 Help
W Surface water Landfill W Ambient air
• Delete selected run | Surface Water | Landfill Ambient Air
Enter Release Activity Below:
Manufacturing
tt Sites [i
(ft sites with identical releases)
Pj Next Release Activity |
General Remarks
f~ No dose calculations required
Inhalation Comment
Note: input release info and press the Calculate button
Stack Releases: | 2,000.00 kg/site/day | 40 days/yr
Fugitive Releases: I 16.00 kg/site/day | 100 days/yr
Calculate Air Concentration
Max annual avg air concentration:
Max 24 hr avg air concentration:
Stack Fugitive
| 4 «E-02 | 3.83E-02 mg/m3
2.05 | 1-75 mij/ni'
V~ Release activities completed? Continue to Exposure Factors page j
Figure 3-2c. General Release Information Page - Ambient Air
Once all the information for a release activity is entered, you may enter another release activity
by clicking the "Next Release Activity" button. If you have finished entering release activities, click on
the "Release activities completed? Continue to Exposure Factors page" button to continue to the
Exposure Factors page (Section 3.1.2).
3.1.1.1 Surface Water Releases
In the Surface Water tab of the General Release Information page (Figure 3-2a), you may enter a
release amount (kg/site/dav) and frequency of discharge (days/year). The model requires flow data for the
body of water receiving the discharge. If the site is a known facility with a known National Pollutant
Discharge Elimination System (NPDES) number, E-FAST V2.0 can access the required flow data for the
site. If there are multiple sites or a single site without any available flow data, E-FAST V2.0 will use flow
data based on typical values for the Standard Industrial Classification (SIC) code of the industry
producing the discharge. These two options are labeled on the page as "Facility" and "SIC Code." The
NPDES number and SIC code options are described in more detail below.
You may also choose whether or not to run PDM for any given surface water release by checking
or unchecking the "Include PDM run" box. If you choose to run PDM, you may select either an average
or a high-end PDM analysis. PDM predicts the number of days per year a facility's discharge will exceed
a chemical 's concentration of concern (COC) in a specific stream or river. The COC values specific to
your analysis are entered on the General Release Information page. You may enter up to three COC
values; this may be useful if the chemical you are assessing has an uncertain COC. If the discharge is at a
known site, a PDM analysis can be performed on a reach with measured flow data from a U.S. Geological
Survey (USGS) gaging station or a reach with only estimated flow values. If the reach has a gaging
station, PDM will use the ranked measured daily flow values from EPA's STORET Daily Flow Statistical
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File (Appendix B) to determine the frequency of exceedence. If only estimated flow data are available
from EPA's Gage File (Appendix B), the frequency of exceedence is estimated using a stochastic
procedure developed by Di Toro (1984) that uses the means and coefficients of variation of stream flow,
effluent flow, and effluent concentration (Appendix C). The streamflow coefficient of variation is
estimated using the mean flow, 7Q10 flow (i.e., 7 consecutive days of lowest flow over a 10-year period),
and empirically-derived coefficients specific to each watershed. Days of exceedence are calculated for
each of the COC values specified on the General Release Information Page. PDM can also base its
calculation on generic, SIC code-based scenarios. When you choose to run PDM within the "General
Population and Ecological Exposure from Industrial Releases" module or the "Down-the-Drain" module
(Sections 3.1 and 3.2, respectively), the setup and execution of PDM is carried out by E-FAST V2.0 using
your data; no additional input is required on your part. You may also run PDM as a stand-alone model;
see Section 3.4.
In addition, if the percent adsorption to wastewater treatment sludge was entered in the
PChem/Fate Inputs screen, a sludge value is calculated. The value is calculated by multiplying the
amount of chemical release to water by the percent adsorbed. The percent adsorbed must be less than or
equal to the wastewater treatment removal. The calculated sludge value is used in estimating exposures to
landfill releases.
You may add a comment to the surface water release by clicking on the "SW comment" button,
typing in the dialog box that appears, and clicking "OK." The text will appear in the output file.
Select a Facility
If a release activity takes place at a known location, you may select "Facility" in the Surface
Water section of the General Release Information page and search for site-specific flow data on the
"Select a Facility" page, which can be accessed by clicking on the tab to the right of the tab for the
General Release Information page. E-FAST V2.0 contains facility and stream data from various EPA
water-related information systems (See Appendix B). Lists of NPDES numbers, facility names, SIC
codes, and reach numbers can be searched using search substrings. (Under the Clean Water Act,
discharges of chemicals to surface waters are required to obtain a permit. A NPDES permit number is a
unique nine-character code, beginning with the two-letter state abbreviation. E-FAST V2.0 only contains
NPDES numbers for permitted facilities in the format ILxxxxxxx, where the first two letters are a state
abbreviation and x is numeric. NPDES numbers for general permits and nonpermitted facilities are not
included.) To search for a facility, fill in the two fields that appear in the following message at the center
of the screen: "Locate facilities where this field [select NPDES, Facility name, SIC code, or Reach
number from the drop-down menu] has the following substring [type in the State abbreviation for
NPDES, first letters of the facility name, first digits of the SIC code, or numbers at the beginning of the
reach number]." Be sure to follow the acceptable NPDES format as described above. If you are searching
by facility name or SIC code, you may restrict the search to a single state or EPA region by clicking the
appropriate button and selecting the state or region from the drop-down menu on the left-hand side of the
screen.
For example, entering AR will produce a listing of all NPDES numbers in the State of Arkansas.
Entering a substring of AR000058 will yield a list of NPDES numbers ranging from AR0000580 to
AR0000589. To search facility names, select "Facility name" in the first field, then enter "Ale" to get a
list of all facility names beginning with those letters. For SIC code searches, entering a substring of 27
will yield a listing of four-digit SIC codes that begin with 27. Reach numbers are unique 11 -digit
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numbers used to identify surface water bodies and can be searched using the first few digits. Reach
numbers consist of the following information:
02xxxxxxxxx
xx03xxxxxxx
xxxx04xxxxx
xxxxxx06xxx
xxxxxxxxO11
Region
Subregion
Accounting unit
Cataloging unit
Segment number
The region number is one of 21 regions, or major river drainage basins, within the United States and
Puerto Rico. Each region contains subregions, accounting units, cataloging units, and segment numbers
based on the number of surface water bodies.
Conduct the search by selecting the "Perform search for facilities" button. E-FAST V2.0 will
display the facilities matching the search strings as shown in Figure 3-3. Select the facility of interest by
double-clicking; you will then be returned to the General Release Information screen.
17 Screening Level Inputs
Release Info Page |
General Release Info Select a facility 1
Release Information - Facility Selection Screen
7 Help |
Locate facilities where this field | Facility name has the following substring: |MALDEN
(*' Search by state
C Search by region
Area of initial search
I All states
NPDES entries in this model must use the following format:
two letter state abbreviation followed by seven digits.
Perform search for facilities
"31
Double click the desired facility
Note: This is an active facility.
NPDES
FACILITY NAME
LOCATION
REACH
REACH NAM

IL0024791
MALDEN STP
MALDEN IL G1337
07130001033
BIG BUREAL
I
MO 0022888
MALDEN INDUSTRIAL PK WWTF
MALDEN MO G38G3
08020204006
LITTLE R

MO 0100030
MALDEN WWTP W
MALDEN MO 638B3
08020204013
WEST DITCI

M00125598
MALDEN INDUSTRIAL PK LAG
MALDEN MO 63863

NY014555B
MALDEN-ON-HUDSON WWTP
SAUGERTIES NY 12477
02020006

zi
LJJ
Jj

|7 iSearch for endangered species in the vicinity of this facility
Figure 3-3. Select a Facility Screen
You may also choose to search for a list of endangered species in the vicinity of the facility.
E-FAST V2.0 contains a database of endangered species obtained from EPA's Endangered Species
Protection Program Database (U.S. EPA, 2004). By selecting this search query, the presence of
endangered species in the vicinity of industrial discharges to surface water can be identified. The location
of endangered species is correlated with the facility location using Federal Information Processing
Standards (FIPS) state and county codes. The endangered species information presented include common
name, taxonomic group, listing action and known occurrence.
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Select an SIC Code
The Standard Industrial Classification (SIC) system was developed by the U.S. Government in
order to provide agencies with a uniform framework for organizing economic, engineering, and scientific
data for a wide range of economic activities. These activities include agriculture, mining, manufacturing,
construction, utilities, retail trade, and finance. Under the SIC system, every establishment, defined as a
single economic production unit such as a factory, a mill, or a mine, is assigned a four-digit numerical
code. The system is structured in such a way that the first one or two digits are used as a broad
classification and the full four digits are used for more detailed recordkeeping. The SIC system has been
periodically revised since its inception to reflect the economy's changing industrial composition and
organization. The classification system currently used by E-FAST V2.0 is based on the 1987 SIC system
and includes facilities in 36 industrial categories. In 1998, the U.S. Office of Management and Budget
(OMB) initiated efforts to replace the SIC system with the North American Industry Classification
System (NAICS), which identifies industries using a six-digit code rather than the four-digit SIC code
(U.S. OMB, 1998). The longer code accommodates the larger number of sectors and allows more
flexibility in designating subsectors. This six-digit code is a major revision that not only provides for
newer industries, but also reorganizes the categories on a production/process-oriented basis (SIC used a
mixture of production-based and market-based categories). The NAICS codes do not directly correspond
to the SIC codes because some SIC codes were split into multiple NAICS codes, and the NAICS system
has 20 broad sectors, whereas the SIC system had 10. Currently, the EPA water-related information
systems used in E-FAST V2.0 do not associate their data with the NAICS codes. When these databases
are updated, E-FAST V2.0 will be updated to search on the basis of NAICS codes. Although the NAICS
codes are now readily available and it is possible to identify a NAICS code for a particular facility, E-
FAST V2.0 does not use NAICS codes. Because there are 27,247 direct discharging facilities reported in
E-FAST V2.0, it is not practical to contact each facility to acquire its NAICS code. (Direct discharge
refers to the discharge of pollutant(s) directly to surface waters of the United States under the NPDES
permit program.) According to representatives from the EPA, the NAICS codes will not be put into the
EPA water-related information systems used in E-FAST V2.0 until the EPA begins to modernize their
systems, which is not scheduled to be done in the immediate future. However, a list of facilities' SIC
codes and their corresponding NAICS codes is currently available through the NAICS Association's
website at http://www.naics.com.
Within E-FAST V2.0, the full four-digit SIC codes are used to classify establishments that
discharge wastewater. E-FAST V2.0 provides receiving stream flows and dilution factors for direct
dischargers in selected SIC codes (i.e., 10th and 50th percentile). The harmonic mean, 30Q5, 7Q10, and
1Q10 flow statistics are provided (See Section 3.1.4.1 for definitions of these flows). You can select such
flow data when the exact location of a discharger to surface water is not known, but the nature of the
discharge facility is known (e.g., a paper mill, an electroplater, etc., as shown in Figure 3-4). In the
Surface Water section of the General Release Information page, click the "SIC code" button. The Select
an SIC Code page will appear in the foreground and the General Release Information page will be hidden.
If necessary, you can alternate between the two pages by clicking on the tabs at the top of the screen. The
Select an SIC Code page presents a list of industrial categories. Double click on the one that best fits the
release activity you are modeling. You will then be returned to the General Release Information page.
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17 Screening Level Inputs
Release Info Page |
General Release Info Select an SIC Code
Release Information - SIC Code Selection Screen
Double-click the desired SIC Description
SIC Description
3
Organic Chemicals Manufacture

Ore Mining & Dressing

Paint Formulation
J
Paper & Paperboard Mills

Paper Mills, except Building Paper Mills

Paperboard Mills

Pesticides Manufacture
A
Figure 3-4. Select an SIC Code Screen
3.1.1.2 Landfill Releases
If you checked "Landfill Releases" on the General Release Information page (Figure 3-2), you
may enter the amount of a chemical sent to a landfill (kg/site/day) and frequency of discharge (days/year)
(Figure 3-2b). E-FAST V2.0 has already calculated the sludge release for you, if you have entered a
surface water release and the percent adsorption to wastewater releases in the PChem/Fate Inputs screen.
Note, however, that if you change the adsorption percentage after the model fills in the sludge release, the
release amount will not automatically update. To generate a new sludge release using the updated
adsorption value, you must re-enter the water release.
As with surface water releases, you may add a comment to the landfill release by clicking on the
"Landfill Comment" button, typing in the dialog box that appears, and clicking "OK." The text will
appear in the output file.
3.1.1.3 Ambient Air Releases
The Ambient Air tab of the General Release Information page (Figure 3-2c) contains two input
lines for release to air: one for stack releases and one for fugitive releases. Stack releases include, but are
not limited to, incineration. To model releases, enter the stack and/or fugitive release amounts and the
corresponding number of days per year. Click on the "Calculate Air Concentration" button. A new screen
called E-FAST2 Downwind Concentration Predictor will appear, containing the release data you just
entered, the stack and fugitive air emission removal rates you specified in the PChem/Fate Inputs screen
(Section 2.0), and modeling parameters. You may edit the SCREEN3 parameters or use the default
values. E-FAST V2.0 uses EPA's SCREEN3 Model (U.S. EPA, 1995a) to estimate the maximum 1-hour
average air concentration for stack and fugitive air emission releases. The model is invoked twice for each
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stack release and twice for each fugitive release- once for a 24-hour maximum and once for the maximum
annual average. Each model run yields a maximum 1-hour average air concentration; conversion factors
(see section 3.1.8) are used to translate the maximum 1-hour average air concentration into a maximum
24-hour or annual average air concentration. In E-FAST V2.0, SCREEN3 models stack emissions as
point sources and fugitive emissions as area sources.
The modeling parameters for SCREEN3 are listed in the Release Information and Meteorological
and Terrain Information tabs. The Release Information tab contains stack parameter data, such as the
stack height, inside stack diameter, stack gas exit velocity, and stack gas temperature for stack releases,
and fugitive parameter data, such as the release height, length of release opening, and width of release for
fugitive releases. An example Release Information tab is shown in Figure 3-5.
Jj^E-FAST2 Downwind Concentration Predictor
E-FAST2 will use EPA's SCREEN3 Model to predict the downwind exposure concentration to your chemical.
Chemical ID 11123502,1
-|qixi
Stack Release
Fugitive Releases
3
2000 kg/site/day |~
40 days/yr % removal via stack release |
1GI kg/site/day | 100 days/yr % removal via fugitive |
Release Information | Meteorological and Terrain Information |
Ambient Temperature
Stack Height
Inside Stack Diameter |
Stack Gas Exit Velocity |~~
Stack Gas Temperature |
293 [K~~
Stack Parameter Data
10 F
0 1 m
3 Release Height
T | Length of Release Opening: [
Number of Sites
Fugitive Parameter Data
I a I* 3
^3
io 3
0.1 |m/sec -^1 Width of Release Opening: |~~
293 |k~~
10 ^
PL
\[^\ Submit to SCREEN3 Model]
Return to E-FAST2 |
Max annual avg concentration:
Max 24 hour avg concentration:
mg/m3
Figure 3-5. SCREEN3 - Release Information
The Meteorological and Terrain Information tab contains data concerning surrounding land use,
terrain height, distance to the residence of interest, and meteorological class. All of these parameters, as
well as ambient temperature, have default values (Table 3-1), but may be changed to conform to a known
facility or location. An example Meteorological and Terrain Information tab is shown in Figure 3-6.
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Table 3-1. Default Values1 for Select Input Parameters to SCREEN3
Parameter
Stack
Fugitive
Stack / Release Height
10m
3 m
Inside Stack Diameter
0.1 m
NA
Stack Gas Exit Velocity
0.1 m/s
NA
Stack Gas Temperature
20°C (293 K)
NA
Ambient Temperature
20°C (293 K)
NA
Length of Release Opening
NA
10m
Width of Release Opening
NA
10m
Surrounding Land Use
Rural
Rural
Meteorological Class
Full
Full
Terrain Height
0m
0m
Distance to Residence
100 m
100 m
'Source: Personal Communication from Lynn Delpire, EPA, OPPT, to Conrad Flessner, EPA, OPPT, May 2002.
These default values were selected to generate conservative concentrations.
E-FAST2 Downwind Concentration Predictoi
E-FAST2 will use EPA's SCREEN3 Model to predict the downwind exposure concentration to your chemical.
Chemical ID 11123502,1 T |
Stack Release | 2000 kg/site/day | 40 days/yr % removal via stack release |
Fugitive Releases | 16 kg/site/day | 100 days/yr £ removal via fugitive |~~
Number of Sites
Release Information Meteorological and Terrain Information I
Surrounding Land Use
Terrain Height
Meteorological Class
r~ Model Using Downwash
|Rural
d
1 0 1"
d
I 100 |m
d
| Full
zi
11 pj) Submit to SCREEN3 Model
Return to E-FAST2
Max annual avg concentration:
Max 24 hour avg concentration:
mg/m3
mg/m3
Figure 3-6. SCREEN3 - Meteorological and Terrain Information
In the Meteorological and Terrain Information tab, you can mark the checkbox for "Model Using
Downwash" if the stack emissions are affected by the building's dimensions. Checking this box produces
a third tab, Downwash Information, which collects information on the dimensions of the building
(default: 100m x 100m x 10m). An example Downwash Information tab is shown in Figure 3-7.
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f|__ E-FAST2 Downwind Concentration Predictor
E-FAST2 will use EPA's SCREEN3 Model to predict the downwind exposure concentration to your chemical.
Chemical ID 11123502,1 3
Stack Release | 2000 kg/site/day | 40 days/yr % removal via stack release | 90
Fugitive Releases | 16 kg/site/day | 100 days/yr % removal via fugitive | 2(7
Release Information | Meteorological and Terrain Information Downwash Information |
Facility Length | 100 |@ ^
Facility Width
Number of Sites | 1
Facility Height | TJ [m
-'ii
1 Submit to SCREEN3 Model |
Return to E-FAST2 |
Max annual avg concentration:
Max 24 hour avg concentration:
mg/m3
Figure 3-7. SCREEN3 - Downwash Information
Once you have entered all of this information, click on the "Submit to SCREEN3 Model" button
to calculate the maximum annual and maximum 24-hour air concentrations. In a few seconds, the
concentrations will appear in the yellow text fields in the lower right-hand corner of the screen. Click on
the "Return to E-FAST2" button to exit SCREEN3. The air concentrations will now appear in the yellow
text fields at the bottom of the Ambient Air section of the General Release Information page.
3.1.2 Exposure Factors Page
When all environmental releases have been entered and you click on the button "Release
activities completed? Continue to Exposure Factors page," you will be taken to the Exposure Factors
page. This page appears as a tab next to the Release Information page, and you may switch back and forth
between these pages by clicking on the tabs at the top of the window. In order to calculate exposures and
doses, E-FAST V2.0 requires exposure parameters for body weight, intake rates, and other exposure
characteristics. The model provides default values for each of these parameters for six age classifications
(adults, youths (children 13-19 years), children 6 to 12 years, children 3 to 5 years, infants 1 to 2 years
old, and infants less than one year old) and two exposure types (acute and chronic for adults; acute only
for children and infants), where appropriate. Figure 3-8 shows an example of the Exposure Factors page.
The values that appear on this screen will vary depending on the age group you selected on the Screening
Level Main page (See Section 3.0). Most of these default values are conservative and are the
recommended values in EPA's Exposure Factors Handbook (U.S. EPA, 1997). You can change these
default values. The E-FAST V2.0 default exposure parameter values are presented in Table 3-2.
3-13
-------
17 Screening Level Inputs
Release Info Page Exposure Factors
Exposure Factors
Chemical ID:
Body weight: |
71.80
kg
Exposure duration (cancer):
30.00
years
Averaging time (cancer):
75.00
years
Drinking water ingestion (chronic):
1.40
L/day
Drinking water ingestion (acute):
6.00
L/day
Fish ingestion (chronic): |
6.00
g/day
Fish ingestion (acute):
129.00
g/day
Inhalation rate':
0.55
m3/hr
1 24 hour/day exposure period is assumed
|p Calculate, save results, and display results pages
7 Help |
Figure 3-8. Exposure Factors Page
To perform all calculations and display the appropriate results pages, select the "Calculate, save
results, and display results pages" button. You will see a progress bar move across the screen as
exposures are calculated and written to disk. When the calculations are done, a dialog box will notify you
that the output file has been saved to your default data drive. Click "OK." The model results are then
displayed in a series of tabs, starting with Environmental Releases. The tabs that follow will vary
depending on the types of releases being modeled. The tabs that may appear include Rivers (See Section
3.1.4), SIC Code (See Section 3.1.5), Lakes (See Section 3.1.6), Landfill (See Section 3.1.7), Inhalation
(See Section 3.1.8), PDM Site-Specific (See Section 3.1.9), and PDM SIC Code (See Section 3.1.10).
3-14
-------
Table 3-2. Default Exposure Parameter Values Used in E-FAST V2.0
I'lxpoMirc
Pill'illlKMlT
Popuhilion
(u'sirs)
l'l\|)OMIIV
T\|)e
l)d;iul(
Value
Source
Com men 1
Body Weight
(BW)
Adult
All
71.8 kg
U.S. EPA
(1997)
Mean adult body weight (EFH Table 7-11).
Youth
(age 13-19)
All
60.2 kg
U.S. EPA
(1997)
Average of mean body weights for youth ages 13-19 years (EFH Table 7-3).
Child
(age 6-12)
All
32.8 kg
U.S. EPA
(1997)
Average of mean body weights for children ages 6-12 years (EFH Table 7-3).
Small Child
(age 3-5)
All
17.5 kg
U.S. EPA
(1997)
Average of mean body weights for children ages 3-5 years (EFH Table 7-3).
Infant
(age 1-2)
All
12.3 kg
U.S. EPA
(1997)
Average of mean body weights for children ages 1-2 years (EFH Table 7-3).
Infant
(age <1)
All
9.1kg
U.S. EPA
(1997)
Mean body weights for children 6-11 months (EFH Table 7-3).
Drinking Water
Intake (IRdw)
Adult
Chronic
1.4 L/day
U.S. EPA
(1997)
Mean adult ingestion rate (EFH Table 3-30).
Adult
Acute
6 L/day
U.S. EPA
(1997)
Ingestion rate for active adults in temperate climates (EFH Table 3-30).
Youth
(age 13-19)
Acute
2 L/day
U.S. EPA
(1997)
95th percentile ingestion rate for children ages 11-19 years (EFH Table 3-30).
Child
(age 6-12)
Acute
1.75 L/day
U.S. EPA
Average of values for youth (age 13-19 years) and Child (age 3-5 years). EFH does
not recommend a rate for age 6-12.
Small Child
(age 3-5)
Acute
1.5 L/day
U.S. EPA
(1997)
90th percentile ingestion rate for children ages 3-5 years (EFH Table 3-30).
Infant
(age 1-2)
Acute
1.5 L/day
U.S. EPA
(1997)
90th percentile ingestion rate for children ages < 3 years (EFH Table 3-30).
Infant
(age < 1)
Acute
0.76 L/day
U.S. EPA
(1997)
95th percentile ingestion rate for children ages < 1 years (EFH Table 3-30).
3-15
-------
Table 3-2. Default Exposure Parameter Values Used in E-FAST V2.0 (Cont'd)
I'lxpoMirc
Pill'illlKMlT
Popuhilion
(u'.irs)
l'l\|)OMIIV
T\|)e
l)d;iul(
Value
Source
Com men 1
Inhalation Rate
(InhR)
Adult
Chronic
13.3 m3/day
U.S. EPA
(1997)
For general population exposure, average of adult male and female means (EFH
Table 5-23); equivalent to 0.55 m3/hr.

Adult
Acute
see
comment
U.S. EPA
(1997)
For consumer exposures: 1.0 m3/hr during product use (based on light activity level)
and 0.55 m3/hr after product use; for general population exposure, 0.55 m3/hr or 13.3
m3/day, assuming exposure period of 24 hr/day (EFH Table 5-23).

Youth
(age 13-19)
Acute
14.0 m3/day
U.S. EPA
(1997)
For consumer and general population exposures: Average of mean long-term values
for males and females age groups 12-14 years and 15-18 years (EFH Table 5-23);
equivalent to 0.58 m3/hr.

Child
(age 6-12)
Acute
12.3 m3/day
U.S. EPA
(1997)
For consumer and general population exposures: Average of mean long-term values
for males and females age groups 6-8 years and 9-11 years (EFH Table 5-23);
equivalent to 0.51 m3/hr.

Small Child
(age 3-5)
Acute
8.3 m3/day
U.S. EPA
(1997)
For consumer and general population exposure: Mean long-term value for age group
3-5 years (EFH Table 5-23); equivalent to 0.35 m3/hr.

Infant
(age 1-2)
Acute
6.8 m3/day
U.S. EPA
(1997)
For consumer and general population exposures: Mean long-term value for age
groups 1-2 year (EFH Table 5-23); equivalent to 0.28 m3/hr.

Infant
(age < 1)
Acute
4.5 m3/day
U.S. EPA
(1997)
For consumer and general population exposure: Mean long-term value for infants
(<1 year) (EFH Table 5-23); equivalent to 0.19 m3/hr.
Fish Ingestion
Rate (IRfish)
Adult
Chronic
6.0 g/day
U.S. EPA
(1997)
Long-term general population average ingestion of freshwater/estuarine fish (EFH
Table 10-81).

Adult
Acute
129 g/day
U.S. EPA
(1997)
Mean serving size for general population (EFH Table 10-82).

Youth
(age 13-19)
Acute
118 g/day
U.S. EPA
(1997)
Average of mean 1-day intakes for males and females ages 12-19 years, consumers
only (EFH Table 10-46).

Child
(age 6-12)
Acute
89 g/day
U.S. EPA
(1997)
Average of mean 1-day intakes for males and females ages 6-11 years, consumers
only (EFH Table 10-46).

Small Child
(age 3-5)
Acute
67 g/day
U.S. EPA
(1997)
Average of mean 1-day intakes for ages < 5, consumers only (EFH Table 10-46).
3-16
-------
Table 3-2. Default Exposure Parameter Values Used in E-FAST V2.0 (Cont'd)
I'lxpoMirc
Pill'illlKMlT
Popuhilion
(u'sirs)
l'l\|)OMIIV
T\|)e
l)d;iul(
Value
Source
C oiii men I

Infant
(age 1-2)
Acute
52 g/day
U.S. EPA
(1997)
Mean quantity of fish consumed per eating occasion for ages 1-2 years, consumer
only (EFH Table 10-45).

Infant
(age < 1)
Acute
NA
NA
NA
Exposure
Duration (ED)
Adult
Chronic
30 years
U.S. EPA
(1997)
For ambient exposures (air, water, and fish ingestion): 95th percentile residential
occupancy value (EFH Table 15-176).

Adult
Chronic
57 years
-
For consumer exposures: Active usage of consumer products during years 18 to 75.

Adult
Acute
1 day
-
Assumed 1 day exposure for acute scenarios.

Youth
(age 13-19)
Acute
1 day
-
Assumed 1 day exposure for acute scenarios.

Child
(age 6-12)
Acute
1 day
-
Assumed 1 day exposure for acute scenarios.

Small Child
(age 3-5)
Acute
1 day
-
Assumed 1 day exposure for acute scenarios.

Infant
(age 1-2)
Acute
1 day
-
Assumed 1 day exposure for acute scenarios.

Infant
(age < 1)
Acute
1 day
-
Assumed 1 day exposure for acute scenarios.
Carcinogenic
Averaging Time
(AT)
Adult
NA
75 years
U.S. EPA
(1997)
Average life expectancy of general population (EFH page 8-1).
Acute
Averaging Time
(AT)
All
Acute
1 day
-
Assumed 1 day exposure for acute scenarios.
EFH = Exposure Factors Handbook (U.S. EPA, 1997)
3-17
-------
3.1.3 Environmental Release Results Page
The Environmental Release Results page (Figure 3-9) presents the calculated total potential (i.e.,
before treatment) environmental releases for each site release to surface water, to landfills (non-
sludge/sludge), in stack emissions, and in fugitive emissions. The box in the upper left-hand corner
shows all of the release activities you entered on the General Release Information page ; you can click on
any release activity to view the results for that activity. In the output fields highlighted in yellow, the total
releases (kg/year) are calculated by multiplying the per site release rate (kg/site/dav), the release days per
year (days/year), and the number of sites. A "Print Page" button at the lower right-hand corner may be
used to generate a hard copy of the data on the screen.
HE33
Close I
J Help |
Release Activity: {Manufacturing Number of Sites: | -j"
Release Values |

Surface Water
Landfill
Stack
Fugitive
Total Releases:[
8,000.00
1.09E+04
8.00E+04
1.600.00
(before treatment)
(kg/yr)
(kg/yr)
|kg/j..)
(kg/jr)
Release days/yr: |
200.00
100.00/200.00
40.00
100.00
(before treatment)

Non-Sludge/Sludge

Per site release
40.00
100.00/4.40
2.000.00
16.00

(kg/site/day)
(kg/site/day)
(kg/site/day)
(kg/site/day)
Screening Level Results
Environmental Releases j Rivers | SIC Code | Lakes | Inhalation | Landfill ] PDM Site ) PDM SIC Code ]
Chern D/Re If
1123502,2
1123502,3
Environmental Release Results
Print Page
Figure 3-9. Environmental Release Results Page
3.1.4 Rivers Results Page
Figure 3-10 shows an example Rivers Results page. The box in the upper left-hand corner shows
all of the release activities that included discharges to rivers; you can click on any release activity to view
the results for that activity. The following are short descriptions of the fields listed in the upper half of
this page:
• Release Activity — can be manufacturing, processing, industrial use, or other. This was entered
in a text field on the left-hand side of the General Release Information page (Figure 3-2).
Facility Name, Location, NPDES, Reach Number, Reach Name — information on the
discharging facility extracted from the E-FAST V2.0 database when searching for a facility
during the data entry procedure (See Section 3.1.1.1).
3-18
-------
Facility on Reach? — indicates whether the facility discharges to the identified reach, discharges
to a tributary stream, or if the discharge point is unknown.
Exposed Population — can be adults, youths 13 to 19 years, children 6 to 12 years, children 3 to
5 years, infants 1 to 2 years, or infants less than one year old. This was entered on the Screening
Level Main page (Figure 3-1).
Discharge Type — indicates whether the facility is a direct discharger that discharges treated
wastewater directly to a surface water body or an indirect discharger that discharges wastewater
to a POTW for treatment.
• Wastewater Treatment (WWT) Removal — percentage of the chemical removed from
wastewater during treatment before discharge to a body of water. This is a chemical-specific
property entered on the PChem/Fate Inputs screen (See Section 2.0).
Release Days — number of days per year that the chemical is discharged, as entered on the
General Release Information page.
Pretreatment Release — rate of release of the chemical by the facility to a wastewater treatment
facility (kg/site/day), as entered on the General Release Information page.
Post-treatment Release — rate of release of the chemical after treatment by a wastewater
treatment facility. The post-treatment release amount is equal to the pretreatment release reduced
by the wastewater treatment removal percentage.
Bioconcentration Factor — indicates the tendency of the chemical to accumulate in living
organisms. This is a chemical-specific property entered on the PChem/Fate Inputs screen (See
Section 2.0).
In addition to these fields, the top portion of the Rivers results page displays a "Print Page" button that
may be used to generate a hard copy of the data on the screen. The hard copy includes the data in all of
the tabs in the lower portion of the screen (General Site Information, Drinking Water Information, Fish
Ingestion Information, and Endangered Species), so there is no need to click the "Print Page" button for
each of these tabs.
3-19
-------
17 Screening Level Results
Environmental Releases Rivers | SIC Code | Lakes | Inhalation ] Landfill ] PDM Site | PDM SIC Code |
Site-Specific Human And Aquatic Exposures to Surface Water Releases
Exposed Population: |Adult
Discharge Type: (Direct
WWT Removal: 1
Release Days: |
Pre-treatment Release: |
Post-treatment Release:)
Bioconcentration Factor:)
Chem ID/Rel tt
Release Activity
Facility Name
Facility Location
NPDESft
Reach Number
Reach Name
Drinking Water Treatment
Manufacturing
MALDEN STP
MALDEN IL B1337
07130001033
BIG BUREAU CR
9.00 %
Facility on Reach? & Yesf* No C Unk. |
General Site Information j Drinking Water Information Fish Ingestion Information Endangered Species I
Aquatic Exposure E stimales - Surlace Water
Flow Descriptor
Harmonic Mean
30Q5
7Q10
1Q10
Flow (MLD)
80.77 |
21.35 |
12.67 1
10.56
| Concentration (ug/L) |
371.42 |
1,405.17 |
2,367.80
2,841.31
Surface Water Comments

? Help
25.00 %
200.00
40.00 kg/site/day
30.00 kg/site/day
30.00 L/kg
Print Page |
Figure 3-10.
Water
Rivers Results Page - Aquatic Exposure Estimates - Surface
Four tabs located in the lower half of the page allow you to view General Site Information,
Drinking Water Information, Fish Ingestion Information, and Endangered Species.
3.1.4.1 Rivers Results Page - General Site Information
Site-specific surface water concentrations are calculated from estimated arithmetic mean and
7Q10 stream flows obtained from an EPA database (See Appendix B). Harmonic mean, 30Q5, and 1Q10
flows are calculated from the 7Q10 flows and arithmetic mean flows. The units of flow are million liters
per day (MLD). The estimated chemical concentrations are presented for each flow rate. The following
are short definitions of the flows displayed in the lower half of the screen.
• Harmonic Mean Flow (SFharmonic) — inverse mean of reciprocal daily arithmetic mean flow
values. In other words, harmonic mean (H) is defined as H = n/[(l/x,) + (l/x2) +...+ (l/xn)] where
x is a particular number in a group of measured values and n is the number of measurements in
the series. These flows are used to generate estimates of chronic human exposures via drinking
water and fish ingestion.
30Q5 Flow (SF30QS) — 30 consecutive days of lowest flow over a 5-year period. These flows are
used to determine acute human exposures via drinking water.
7Q10 Flow (SF7Q10) — 7 consecutive days of lowest flow over a 10-year period. These flows are
used to calculate estimates of chronic surface water concentrations to compare with the COCs for
aquatic life.
3-20
-------
1Q10 Flow (SF1Q10) — single day of lowest flow over a 10-year period. These flows are used to
calculate estimates of acute surface water concentrations to compare with the COCs for aquatic
life.
At the bottom of the page is a text box containing any comments entered by clicking on "SW comment"
on the General Release Information page (See Section 3.1.1.1).
Estimation of Surface Water Exposure Concentrations in Rivers and Streams
E-FAST V2.0 uses the following equation to calculate surface water concentrations in free-
flowing rivers and streams:
f WWT
WWRxCF lxl
100 J (EcL- 3_1)
SWC =
SF x CF2
where:
swc
= Surface water concentration (parts per billion (ppb) or |_ig/L)
WWR
= Chemical release to wastewater (kg/day)
WWT
= Removal from wastewater treatment (%)
SF
= Estimated flow of the receiving stream (MLD)
CF1
= Conversion factor (109 j^ig/kg)
CF2
= Conversion factor (106 L/day/MLD)
The amount of chemical released to wastewater and the estimated removal from wastewater
treatment are input values to this equation. The conversion factor of 109 converts the chemical release
from kg to (.ig. This value is then divided by the stream flow in MLD, which is converted to L/day (106
L/day/MLD). The results of this equation are chemical concentrations in units of (.ig/L. For very dilute
aqueous solutions (such as surface water concentrations estimated by E-FAST V2.0), the units of j^ig/L
and ppb can be considered equivalent.
This equation is valid for both site-specific and generic-release situations. Generic analyses using
SIC codes can be performed when the locations of chemical releases are unknown or when there are no
available streamflow data for the receiving stream.
E-FAST V2.0 calculates surface water concentrations for four streamflow conditions as shown in
Equation 3-1. The equations used to estimate the harmonic mean, 30Q5, and 1Q10 flows from estimated
arithmetic mean and 7Q10 flows also are presented below (Versar, 1992). The units for the arithmetic
mean flow (SFanthmetlc) and the 7Q10 flow (SF7Q10) used in these equations (Equations 3-2 through 3-4) are
MLD. The factor 0.409 is used to convert MLD to units of cubic feet per second (cfs).
Harmonic mean stream flows are used to generate estimates of chronic human exposures via
drinking water and fish ingestion.
3-21
-------
SF. . (MLD) 4 1.194 x
harmonic v '
0.409 x SF
MLD
x | 0.409 x SF,
MLD
1Q10
(Eq. 3-2)
0.409
cfi
MLD
SF30Q5 (30 consecutive days of lowest flow over a 5-year period) stream flows are used to
generate estimates of acute human exposures via drinking water and fish ingestion.
SF30Q5 (MLD) 4 1782
0.409
cfi x w
MLD 1Q1°
0.966
(Eq. 3-3)
0.409
cfi
MLD
SF7Q10 (7 consecutive days of lowest flow over a 10-year period) stream flows are used to
generate estimates of exceedences of chronic COCs for aquatic life.
SFjqjq (single day of lowest flow over a 10-year period) stream flows are used to determine if
there are acute ecological concerns.
SFlQ10 (MLD) 4 0.843
( r \ 0.993
°-409 ^ x SFjqio J (Eq. 3-4)
0.409
MLD
3.1.4.2 Rivers Results Page - Drinking Water Information
The Drinking Water Information tab (Figure 3-11) presents the acute and chronic exposure doses
for individuals who ingest drinking water from streams and rivers that receive wastewater discharges
containing the chemical of concern. The first column, "Exposure Types," lists three different
measurements of exposure. To the right of each, under the "Results" heading, is the corresponding
exposure value. The subsequent columns contain exposure factors that were entered in the Exposure
Factors page (See Section 3.1.2). The exposure types and exposure factors are defined below.
3-22
-------
!7f Screening Level Results
l-lnM
Environmental Releases Rivers | SIC Code | Lakes | Inhalation ] Landfill ] PDM Site | PDM SIC Code j
Site-Specific Human And Aquatic Exposures to Surface Water Releases
Chern ID/Rel ft
Release Activity:
Facility Name:
Facility Location:
NPDEStt:
Reach Number:
Reach Name:
Drinking Water Treatment:
Facility on Reach?
Manufacturing
MALDEN STP
MALDEN IL G1337
07130001033
BIG BUREAU CR
9.00 %
r Yes r Ho C Unk
Exposed Population: |Adult
Discharge Type: (Direct
WWT Removal: I
Release Days: |
Pre-treatment Release: |
Post-treatment Release:)
Bioconcentration Factor:)
General Site Information ; Drinking Water Information i Fish Ingestion Information I Endangered Species I
? Help
25.00 %
200.00
40.00 kg/site/day
30.00 kg/site/day
30.00 L/kg
Print Page |
Drinking Water Exposuie Estimates
J Exposure Types Results j ED (yrs) AT (yrs) BW (kg) [ IRdw (L/day)
Cancer
| LAD D pot (mg/kg/day) |
1.44E-03 j
30.00 |
75.00 |
71.80 j
1.40
LADCpot (mg/L)
7.41 E-02 [
30.00 |
75.00 |~~
NA |
NA
Acute
| ADR pot (mg/kg/day) |
0.11 |
NA |
1 day |
71.80 |
6.00
Figure 3-11. Rivers Results Page - Drinking Water Exposure Estimates
Exposure Types
Potential Lifetime Average Daily Dose (LADDPOT) — from drinking water intake; calculated to
represent chronic exposures to contaminated drinking water over a lifetime. These doses are
generally used for cancer calculations.
• Potential Lifetime Average Daily Concentration (LADCPOT) — of the chemical of concern in
drinking water; calculated to represent chronic lifetime concentrations. These concentrations are
generally used for cancer calculations.
Potential Acute Dose Rate (ADRPOT) — from drinking water intake; normalized over a shorter
time period (e.g., 1 day).
Exposure Factors
• Exposure Duration (ED) — number of years a resident drinks contaminated water.
E-FAST V2.0 uses a default value of 30 years; see Table 3-2.
Averaging Time (AT) — period of time over which exposures are averaged.
Body Weight (BW) — mean body weight for the population being assessed.
Drinking Water Ingestion Rate (IRdw) — used for calculating acute and chronic exposures.
Estimation of Drinking Water Potential Doses
To estimate how much of a given chemical a person will ingest through drinking water, E-FAST
V2.0 uses the equations presented below. These equations convert an estimated surface water
concentration to a drinking water exposure estimate. The surface water concentration (in ug/L) is
3-23
-------
adjusted to account for any removal of the chemical during treatment of the drinking water and is then
multiplied by the estimated drinking water ingestion rate in liters per day, the number of release days per
year, and exposure duration in years. This product is then divided by body weight (in kg) and averaging
time to yield the exposure dose in mg/kg/day.
SWC
ADRpot 4
1 )
DWT
100
IR
dw
RD x CF1
(Eq. 3-5)
BW x AT
SWC
1 )
DWT
LADDpoT 4
100
IR
dw
ED x RD x CF1
(Eq. 3-6)
BW x AT x CF2
SWC
1 )
DWT
LADCpot 4
100
ED x RD x CF1
(Eq. 3-7)
AT x CF2
where:
adrpot
Potential Acute Dose Rate (mg/kg/day)
laddpot
Potential Lifetime Average Daily Dose (mg/kg/day)
LADCPot =
Potential Lifetime Average Daily Concentration in drinking water (mg/L)
SWC
Surface water concentration (ppb or (ig/L)
DWT
Removal during drinking water treatment (%)
' Rdw
Drinking water intake rate (L/day)
RD
Release days (1 day for ADRP0T; days/yr for LADDP0T and LADCP0T)
BW
Body weight (kg)
ED
Exposure duration (years for LADCP0T and LADDP0T; see Table 3-2)
AT
Averaging time (years for LADDP0T and LADCP0T; day for ADRP0T)
CF1
Conversion factor (10"3 mg/(.ig)
CF2
Conversion factor (365 days/year)
The harmonic mean streamflow concentration is used to calculate the LADDP0T and LADCP0T-
The 30Q5 streamflow concentration is used to calculate the ADRP0T. This is consistent with EPA's OW
guidance (U.S. EPA, 1991). The mean (central tendency) drinking water intake rate is used to calculate
LADDpot and the high-end drinking water intake rate is used to calculate ADRP0T.
3.1.4.3 Rivers Results Page - Fish Ingestion Information
The Fish Ingestion Information tab (Figure 3-12) presents the exposure doses for individuals who
ingest fish from streams and rivers that receive wastewater discharges containing the chemical of concern.
The first column, "Exposure Types," lists three different measurements of exposure. To the right of each,
under the "Results" heading, is the corresponding exposure value. The subsequent columns contain
exposure factors that were entered in the Exposure Factors page (Section 3.1.2). The exposure types and
exposure factors are defined below.
3-24
-------
Exposure Types
Potential Lifetime Average Daily Dose (LADDPOT) — from ingestion of fish tissue; calculated
to represent chronic exposures to fish over a lifetime. These doses are generally used for cancer
calculations.
Potential Lifetime Average Daily Concentration (LADCPOT) — of the chemical of concern in
ingested fish tissue; calculated to represent chronic lifetime concentrations. These concentrations
are generally used for cancer calculations.
Potential Acute Dose Rate (ADRPOX) — from ingestion of fish tissue; normalized over a shorter
time period (e.g., 1 day).
Exposure Factors
Exposure Duration (ED) — length of time the fish consumer is exposed.
Averaging Time (AT) — period of time over which exposures are averaged.
Body Weight (BW) — mean body weight for the population being assessed.
Fish Ingestion Rate (IRr,sh) — used for calculating acute and chronic exposures.
IT" Screening Level Results
Environmental Releases Rivers j SIC Code | Lakes | Inhalation ] Landfill | PDM Site ] PDM SIC Code |
Site-Specific Human And Aquatic Exposures to Surface Water Releases
9 Help
Chem ID/Rel #
Release Activity:
Facility Name:
Facility Location:
NPDES#:
Reach Number:
Reach Name:
Drinking Water Treatment:
Facility on Reach?
Manufacturing
Exposed Population: [Adult
MALDEN STP
MALDEN IL 61337
07130001033
BIG BUREAU CR
Discharge Type: |Direct
WWT Removal:!
Release Days: I
Pre-treatment Release:]
Post-treatment Release: |
Bioconcentration Factor: |
25.00 %
-------
exposures and the mean serving size is used to calculate acute fish ingestion exposures for adults. This is
in contrast to drinking water estimates, where the distinction between acute and chronic values is made on
the basis of stream flows and on ingestion rates. The reason for this difference is that it takes time for
chemical concentrations to accumulate in fish; therefore, the harmonic mean flow is used to calculate
concentrations for both acute and chronic scenarios. It is not appropriate to use a very low streamflow
value that occurs rarely as the basis for calculating a chemical residue in fish.
SWC x BCF x IR x rd x CF1
ADRpoT 4 fish
(Eq. 3-8)
BW x AT
LADD
POT
SWC x BCF x IR.
4 jis"
ED x rd x CF1
(Eq. 3-9)
BW x AT x CF2
LADCpoT 4
SWC x BCF x ED x RD x CF1
AT x CF2
(Eq. 3-10)
where:
ADRP0T
LADDpoi
LADCpoi
SWC
BCF
IRfish
RD
BW
ED
AT
CF1
CF2
Potential Acute Dose Rate (mg/kg/day)
Potential Lifetime Average Daily Dose (mg/kg/day)
Potential Lifetime Average Daily Concentration in fish tissue (mg/kg)
Surface water concentration (ppb or j^ig/L)
Estimate of chemical's bioconcentration potential (L/kg)
Fish ingestion rate (kg/day)
Release days (1 day for ADRP0T; days/yr for LADDP0T and LADCP0T)
Body weight (kg)
Exposure duration (years for LADCP0T and LADDP0T; see Table 3-2)
Averaging time (years for LADCP0T and LADDP0T; day for ADRP0T)
Conversion factor (10 3 mg/(.ig)
Conversion factor (365 days/year)
3.1.4.4 Rivers Results Page - Endangered Species
The Endangered Species tab (Figure 3-13) presents the endangered species known (or possible) to
exist in the vicinity of streams and rivers that receive wastewater discharges containing the chemical of
concern. The location of endangered species is correlated with the facility location via FIPS State and
county codes. The endangered species information is presented in six columns and includes common
name, county and State, taxonomic group (e.g., mammals, birds, fish, plants, reptiles, amphibians, clams,
etc.), listing action (listing, proposed, delisting), and known occurrence (true = known, false = possible).
The data were obtained from EPA's Endangered Species Protection Program (ESPP) Databases
(U.S. EPA, 2004). The ESPP is a cooperative effort between the U.S. Fish and Wildlife Service (FWS),
EPA Regions, States, and pesticide users. ESPP is located in the Field and External Affairs Division
(FEAD) of the Office of Pesticide Programs (OPP).
3-26
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0 Screening Level Results
Close I
Environmental Releases Rivers j SIC Code | Lakes ) Inhalation ] Landfill ] PDM Site | PDM SIC Code ]
7 Help |
Release Activity: |Manufacturing Exposed Population: [Adult
Facility Name: |MALDEN STP Discharge Type: jDirect
Facility Location: |MALDEN IL G1337 WWT Removal:! 25.00 %
NPDES#: |IL0024791 Release Days:| 200.00
Reach Number: 107130001033 Pre-treatment Release: | 40^00^ kg/site/day
Reach Name: |BIG BUREAU CR Post-treatment Release: | 3110(1 kg/site/day
Drinking Water Treatment: | 9.00 % Bioconcentration Factor: | 31L00 L/kg
Facility on P'ir" P"90
General Site Information ) Drinking Water Information | Fish Ingestion Information Endangered Species |
Endangered Species
| Common Name
| County
| State
|T ax onomi c Group
jAction
|Known Occurrence?
r
ASTER, DECURRENT FALSE
1 BUREAU
I11
Plant
Listing
True
BAT, INDIANA
BUREAU
IL
Mammal
Listing
False

EAGLE, BALD
BUREAU
IL
Bird
Listing
True

Site-Specific Human And Aquatic Exposures to Surface Water Releases
Chem 10/Rel tt
1123502,1
Figure 3-13. Rivers Results Page - Endangered Species
3.1.5 SIC Code Results Page
The SIC Code Results page (Figure 3-14) presents the releases, and drinking water and fish
ingestion exposures for discharge activities that were entered using SIC codes (Section 3 .1.1.1), as
opposed to specific facilities. The exposure factors are derived from EPA s Exposure Factors Handbook
(U.S. EPA, 1997). The box in the upper left-hand corner of the tab contains a list of every release activity
that you elected to model using SIC codes; click on any of the release activities in the list to view the
results for that activity.
The following are short descriptions of the fields listed in the upper half of this page. The values
in the fields are those entered previously, as noted.
• Release Activity — can be manufacturing, processing, industrial use, or other. This was entered
in a text field on the left-hand side of the General Release Information page (Figure 3-2).
SIC Code Description — text description of the industry selected in the Select an SIC code
page.
SIC Codes — the 4-digit code or codes assigned to the industry selected.
• Wastewater Treatment (WWT) Removal — percentage of the chemical removed from
wastewater during treatment before discharge to a body of water. This is a chemical-specific
property entered on the PChem/Fate Inputs screen (See Section 2.0).
Release Days — number of days per year that the chemical is discharged, as entered on the
General Release Infonnation page.
3-27
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Bioconcentration Factor — indicates the tendency of the chemical to accumulate in living
organisms. This is a chemical-specific property entered on the PChem/Fate Inputs screen (See
Section 2.0).
Exposed Population — can be adults, youths 13 to 19 years, children 6 to 12 years, children 3 to
5 years, infants 1 to 2 years, or infants less than one year old. This was entered on the Screening
Level Main page (Figure 3-1).
Pretreatment Release — rate of release of the chemical by the facility to a wastewater treatment
facility (kg/site/day), as entered on the General Release Information page.
Post-treatment Release — rate of release of the chemical after treatment by a wastewater
treatment facility. The post-treatment release amount is equal to the pretreatment release reduced
by the wastewater treatment removal percentage.
In addition to these fields, the top portion of the SIC Code results page displays a "Print Page" button that
may be used to generate a hard copy of the data on the screen. The hard copy includes the data in all of
the tabs in the lower portion of the screen (General SIC Code Information, Drinking Water Information, and
Fish Ingestion Information), so there is no need to click the "Print Page" button for each of these tabs.
Environmental Releases | Rivers SIC Code j Lakes ] Inhalation | Landfill | PDM Site | PDM SIC Code ]
Print Page
Release Activity: |Processing
SIC Code Description: |Paint Formulation
SIC Codes: [2851
Exposed Population: [Adult
WWT Removal:
Release Days:
Bioconcentration Factor:
Pre-treatment Release:]
Post-treatment Release:[
30 L/kg Drinking Water Treatment:[
100
9.00
Chetn ID/Rel tt
1123502,2
Sic Code Based Human and Aquatic Exposures to Surface Water Releases
General SIC Code Information | Drinking Water Information ] Fish Ingestion Information
Aquatic Exposure Estimates - Surface Water
Flow descriptor
| Harmonic Mean |
30Q5
7Q10
1Q10
50 %\\e

Flow (MLD)
21G.47 |
G0.31
37.13
30.71
Concentration (ug/L)
55.43 I
198.97 |
323.19
390.75
10 %ile
Flow (MLD)
35.44
12 51
7.29
6.10
Concentration (ug/L)
338.60 |
959.23 |
1,646.09
1,967.21
SIC Code Comments:
Figure 3-14. SIC Code Results Page - Aquatic Exposure Estimates - Surface
Water
Three tabs located in the lower half of the page allow you to view three sets of results: General
SIC Code Information, Drinking Water Information, and Fish Ingestion Information.
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3.1.5.1 SIC Code Results Page - General SIC Code Information
The General SIC Code Information tab displays flow rates and concentrations, at both the 10th
and 50th percentiles, under four flow conditions: harmonic mean, 30Q5, 7Q10, and 1Q10. SIC code-
based surface water concentrations are calculated from the 10th and 50th percentile stream flows obtained
from the Stream Dilution Factor Program (SDFP) for 36 industrial categories. (SDFP is a software
program originally developed by the OW to obtain effluent and stream flow frequency distributions for a
given industrial category (SIC code). Revised by OPPT, the major purpose of SDFP is to (1) retrieve
receiving stream flow data for facilities in a particular SIC code (direct dischargers), (2) calculate dilution
factors for each facility (receiving stream flow divided by effluent flow), and (3) rank the flow data and
dilution factors and report the results in terms of percentiles. See Appendix B for more details.)
Harmonic mean, 30Q5, and 1Q10 flows are calculated from the 7Q10 flows and arithmetic mean flows.
The units of flow are MLD.
The following are short descriptions of the percentiles and flows displayed in this tab:
• 50th Percentile Results — exposure calculations based on the median (i.e., 50th percentile)
surface water concentrations and represent central tendency exposure. These flows are used to
represent mid-sized stream flows.
10th Percentile Results — exposure calculations based on the high-end (i.e., upper 10th
percentile) surface water concentrations and represent the bounding high-end exposures. These
flows are used to represent small streams.
• Harmonic Mean Flow (SFharmonic) — inverse mean of reciprocal daily arithmetic mean flow
values. In other words, harmonic mean (H) is defined as H = n/[(l/xj) + (l/x2) +...+ (l/xn)] where
x is a particular number in a group of measured values and n is the number of measurements in
the series. These flows are used to generate estimates of chronic human exposures via drinking
water and fish ingestion.
30Q5 Flow (SF30Q5) — 30 consecutive days of lowest flow over a 5-year period. These flows are
used to determine acute human exposures via drinking water.
7Q10 Flow (SF7Q10) — 7 consecutive days of lowest flow over a 10-year period. These flows are
used to calculate estimates of chronic surface water concentrations to compare with the
concentrations of concern for aquatic life.
1Q10 Flow (SF1Q10) — single day of lowest flow over a 10-year period. These flows are used to
calculate estimates of acute surface water concentrations to compare with the concentrations of
concern for aquatic life.
The calculations used to estimate the SIC Code-based surface water concentrations are presented
in Section 3.1.4.1, Equations 3-1 to 3-4.
At the bottom of the page is a text box containing any comments entered by clicking on "SW
comment" on the General Release Information page (See Section 3.1.1.1)
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3.1.5.2 SIC Code Results Page - Drinking Water Information
The Drinking Water Information tab (Figure 3-15) presents the predicted exposure doses for
individuals who ingest drinking water from streams and rivers that receive wastewater discharges
containing the chemical of concern. The first column, "Exposure Type," lists three different
measurements of exposure. To the right of each, under the "Results" heading, are the corresponding 50th
and 10th percentile exposure values. The subsequent columns contain exposure factors that were entered
in the Exposure Factors page (See Section 3.1.2). The exposure types and exposure factors are defined
below.
X, Screening Level Results
Environmental Releases | Rivers SIC Code | Lakes ] Inhalation | Landfill ] PDM Site | RDM SIC Code ]
Sic Code Based Human and Aquatic Exposures to Surface Water Releases
Chem ID/Rel tt
naE
? Help J Print Page
Release Activity: |Processing

Exposed Population: jAdult

SIC Code Description: |Paint Formulation
SIC Codes: |2851
WWT Removal: |
25
%
Pre-treatment Release:)
16
Release Days:|
100

Post-treatment Release:]
12
Bioconcentration Factor: |
30
L/kg
Drinking Water Treatment:]
9.00
kg/site/day
12 kg/site/day
Drinking Water Exposure Estimates
Exposure Types
| 50%ile Res. |
10%ile Res.
| ED [yfs)
AT [yrs]
BW (kg) |
IRdw (L/day)
Cancer
LAD D pot (mg/kg/day)
1.08E-04 |
6.58E-04
30.00 |
75.00 |
71.80 |
1.40
LADCpot (mg/L]
5.53E-03 |
3.38E 02
30.00 |
75.00 |
NA |
NA
Acute
| ADR pot (mg/kg/day)
1.51E-02
7.29E-02
NA|
1 day |
71.80
6.00
Figure 3-15. SIC Code Results Page - Drinking Water Exposure Estimates
Exposure Types
Potential Lifetime Average Daily Dose (LADDPOT) — from drinking water intake; calculated to
represent chronic exposures to contaminated drinking water over a lifetime. These doses are
generally used for cancer calculations.
e Potential Lifetime Average Daily Concentration (LADCPOT) — of the chemical of concern in
drinking water; calculated to represent chronic lifetime concentrations. These concentrations are
generally used for cancer calculations.
Potential Acute Dose Rate (ADRPOX) — from drinking water intake; normalized over a shorter
time period (e.g.. 1 day).
The calculations of these values are presented in Section 3.1.4.2, Equations 3-5 through 3-7.
3-30
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Exposure Duration (ED) — number of years a resident drinks contaminated water.
E-FAST V2.0 uses a default value of 30 years; see Table 3-2.
Averaging Time (AT) — period of time over which exposures are averaged.
Body Weight (BW) — mean body weight for the population being assessed.
Drinking Water Ingestion Rate (IRdw) — used for calculating acute and chronic exposures.
3.1.5.3 SIC Code Results Page - Fish Ingestion Information
The Fish Ingestion Information tab (Figure 3-16) presents the acute and chronic exposure doses
for individuals who ingest fish from streams and rivers that receive wastewater discharges containing the
chemical of concern. The first column, "Exposure Types," lists three different measurements of exposure.
To the right of each, under the "Results" heading, are the corresponding 50th and 10th percentile
exposure values. The subsequent columns contain exposure factors that were entered in the Exposure
Factors page (See Section 3.1.2). The exposure types and exposure factors are defined below.
}£f Screening Level Results
Environmental Releases | Rivers SIC Code j Lakes | Inhalation | Landfill | PDM Site | PDM SIC Code ]
Sic Code Based Human and Aquatic Exposures to Surface Water Releases
Release Activity: [Processing Exposed Population: |Adult
SIC Code Description: |Paint Formulation
SIC Codes: [2851
WWT Removal: | 25 % Pre-treatment Release:]"
Release Days:] 100 Post-treatment Release:]"
Bioconcentration Factor: | 30 L/fcg Drinking Water Treatment^
General SIC Code Information | Drinking Water Information Fish Ingestion Information [
Fish Ingestion Exposure Estimates
Exposure Types
| 50%ile Res. 1
10Ziie Res.
| ED (yrs)
AT (yis) j
BW (kg) |
IR fish (g/day)
Cancer
| LAD D pot (mg/kg/day)
1.52E-05 |
9.30E-05
30.00 |
75.00 |
71.80 |
6 00
j LADCpot (mg/kg)
0.10 I
i„
30.00 |
75.00 |
NA]
NA
Acute
| ADR pot (mg/kg/day)
2.99E 03
1.83E-02
NA |
1 day |
71.80 |
129.00
Figure 3-16. SIC Code Results Page - Fish Ingestion Exposure Estimates
Exposure Types
Potential Lifetime Average Daily Dose (LADDPOT) — from ingestion of fish tissue; calculated
to represent chronic exposures to fish over a lifetime. These doses are generally used for cancer
calculations.
• Potential Lifetime Average Daily Concentration (LADCPOT) — of the chemical of concern in
ingested fish tissue; calculated to represent chronic lifetime concentrations. These concentrations
are generally used for cancer calculations.
HiEEl
Close I
7 Help ;] Print Page
kg/site/day
12 kg/site/day
9.00 %
3-31
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Potential Acute Dose Rate (ADRPOT) — from ingestion of fish tissue; normalized over a shorter
time period (e.g., 1 day).
The calculations of these values are presented in Section 3.1.4.3, Equations 3-8 through 3-10.
Exposure Factors
• Exposure Duration (ED) — number of years a resident consumes contaminated fish.
E-FAST V2.0 uses a default value of 30 years; see Table 3-2.
Averaging Time (AT) — period of time over which exposures are averaged.
Body Weight (BW) — mean body weight for the population being assessed.
Fish Ingestion Rate (IRfish) — used for calculating acute and chronic exposures.
3.1.6 Lakes Results Page
Figure 3-17 shows an example Lakes Results page. The box in the upper left-hand corner shows
all of the release activities that included discharges to lakes, bays estuaries, or oceans; you can click on
any release activity to view the results for that activity. The following are short descriptions of the fields
listed in the upper half of this page.
• Release Activity — can be manufacturing, processing, industrial use, or other. This was entered
in a text field on the left-hand side of the General Release Information page (Figure 3-2).
Facility Name, Location, NPDES, Reach Number, Reach Name — information on the
discharging facility extracted from the E-FAST V2.0 database when searching for a facility
during the data entry procedure (See Section 3.1.1.1).
Facility on Reach? — indicates whether the facility discharges to the identified reach, discharges
to a tributary stream, or if the discharge point is unknown.
Exposed Population — can be adults, youths 13 to 19 years, children 6 to 12 years, children 3 to
5 years, infants 1 to 2 years, or infants less than one year old. This was entered on the Screening
Level Main page (Figure 3-1).
Discharge Type — indicates whether the facility is a direct discharger that discharges treated
wastewater directly to a surface water body or an indirect discharger that discharges wastewater
to a POTW for treatment.
• Wastewater Treatment (WWT) Removal — percentage of the chemical removed from
wastewater during treatment before discharge to a body of water. This is a chemical-specific
property entered on the PChem/Fate Inputs screen (See Section 2.0).
Release Days — number of days per year that the chemical is discharged, as entered on the
General Release Information page.
Pretreatment Release — rate of release of the chemical by the facility to a wastewater treatment
facility (kg/site/day), as entered on the General Release Information page.
3-32
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Post-treatment Release — rate of release of the chemical after treatment by a wastewater
treatment facility. The post-treatment release amount is equal to the pretreatment release reduced
by the wastewater treatment removal percentage.
Bioconcentration Factor — indicates the tendency of the chemical to accumulate in living
organisms. This is a chemical-specific property entered on the PChem/Fate Inputs screen (See
Section 2.0).
17 Screening Level Results
Environmental Releases | Rivers | SIC Code Lakes j Inhalation | Landfill | PDM Site | PDM SIC Code ]
Site-Specific Human and Aquatic Exposures to Surface Water Releases: Lakes, Bays, Estuaries, and Oceans

Chem ID/Rel tt
Release Activity:
Facility Name:
Facility Location:
NPDES Permit Number:
Reach Number:
Reach Name:
MOSEL TN Wl 530831500
Exposed Population:[AduiT~
Discharge Type:|Direct
WWT Removal:!
Release Days:|
04030101004
L MICHIGAN
Pre-treatment Release:|
Post-treatment Release^
Facility on Reach? <~ Yet C Wo C Unk. | Bioconl;Bn,Ia,ilJn FacloI:f
General Lake Information | Fish Ingestion Information | Endangered Species ]
Dilution Factois and Water Concentrations
Flow Descriptor
Acute Scenario
Chronic Scenario
Dilution Factor
1.15E+04 yg/L
1.15E+04 ug/L
Lake Comments
2 kg/site/day
1-5 kg/site/day
30 L/kg
Print Page
Figure 3-17. Lakes Results Page
Concentrations
Dilution Factors and Water
Three tabs located in the lower half of the page allow you to view General Lake Information, Fish
Ingestion Infonnation, and Endangered Species. The "Print Page" button at the right-hand side of the tabs
may be used to generate a hard copy of the data on the screen. The hard copy includes the data in all of
the tabs in the lower portion of the screen (General Lake Information, Fish Ingestion Information, and
Endangered Species), so there is no need to click the ''Print Page" button for each of these tabs.
3.1.6.1 Lakes Results Page - General Lake Information
The General Lake Information tab contains dilution factors and resulting surface water
concentrations for lakes, bays, estuaries, and oceans. No simple streamflow value represents dilution in
these types of water bodies. To account for further dilution in the water body, dilution factors for the
water body of interest are used. Measured dilution factors are typically between 1 (representing no
dilution) and 200 and are based on NPDES permits or regulatory policy.
Dilution factors are used to calculate all fish tissue concentrations. Acute dilution factors are
used to calculate potential ADRP0T and chronic dilution factors are used to calculate potential LADDPOT
and LADCppi. If an acute dilution factor is available but a chronic dilution factor is not available, then
3-33
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the chronic value is assumed to be equal to the acute value. If a chronic value is available, but no acute
value is available, then the acute value is assumed to be one. E-FAST V2.0 does not calculate potential
drinking water exposures resulting from releases to estuaries and bays because they are not potable
waters. Potential drinking water exposures are also not calculated for releases to lakes because of high
uncertainty about appropriate dilution factors.
Estimation of Surface Water Exposure Concentrations in Lakes. Bays, Estuaries. and Oceans
E-FAST V2.0 uses the following equation to calculate surface water concentrations in still bodies
such as bays, lakes, and estuaries:
WWR
SWC 4-
1 . wwf"
100
CF1 (Eq. 3-11)
PF x CF2 x DF
where:
SWC = Surface water concentration (ppb or (ig/L)
WWR = Chemical release to wastewater (kg/day)
WWT = Removal from wastewater treatment (%)
PF = Effluent flow of the discharging facility (MLD)
DF = Acute or chronic dilution factor used for the water body (typically
between 1 and 200)
CF1 = Conversion factor (109 (ig/kg)
CF2 = Conversion factor (106 L/day/MLD)
Acute and chronic dilution factors, supplied by the States (or Federal Government), were used if
they were available. If the dilution factors were not available, a value of 1 was assigned for the acute and
chronic dilution factors.
Immediate mixing of effluent discharges to lakes, bays, and estuaries does not occur because
these water bodies have slow-moving and/or tidal fluctuations that prevent complete mixing. Therefore,
modeling techniques and tracer studies are used to develop mixing zone values for these types of water
bodies. These mixing zone values are then used to develop dilution factors for estimating concentrations
of chemicals in lakes, bays, and estuaries. A mixing zone is defined as an area within which water quality
criteria can be exceeded. Mixing zones can be associated with either acute or chronic aquatic toxicity
criteria. Acute mixing zones are sized to prevent lethality to passing organisms. Chronic mixing zones
are sized to protect the ecology of the water body as a whole. The acute mixing zone is referred to as the
"zone of initial dilution" and is smaller than the chronic mixing zone.
3.1.6.2 Lakes Results Page - Fish Ingestion Information
The Fish Ingestion Information tab (Figure 3-18) presents the estimated acute and chronic
potential exposure doses for people who ingest fish from lakes, bays, estuaries, and oceans that receive
wastewater discharges containing the chemical of concern. The first column, "Exposure Types," lists
three different measurements of exposure. To the right of each, under the "Results" heading, is the
corresponding exposure value. The subsequent columns contain exposure factors that were entered in the
Exposure Factors page (Section 3.1.2). The exposure types and exposure factors are defined below.
3-34
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!7T Screening Level Results
JdjsJ
Environmental Releases | Rivers | SIC Code Lakes j Inhalation ] Landfill | PDM Site | PDM SIC Code ]
Site-Specific Human and Aquatic Exposures to Surface Water Releases: Lakes, Bays, Estuaries, and Oceans

Chem ID/Rel #
Release Activity:
Facility Name:
Facility Location:
NPDES Permit Number:
Reach Number:
Reach Name:
Facility on Reach?
MOSEL TN Wl 530831500
Exposed Population:(Adult
Discharge Type:|Direct
WWT Removahf
Release Days:|
04030101004
L MICHIGAN
r Yes C No r Unk.
Pre-treatment Release:|
Post-treatment Release:^
Bioconcentration Factor:|~
200
2 kg/site/day
1-5 kg/site/day
30 L/kg
General Lake Information Fish Ingestion Information | Endangered Species ]
Fish Ingestion Exposure Estimates
t Page |
Exposure Types
Results
ED (yrs)
! AT [yrs]
BW (kg)
1R fish (g/day)
Cancer
| LAD D pot (mg/kg/day) |
6.34E-03 |
30.00
75.00 |
71.80
6.00
( LADCpot (mg/kg)
75.87 |
30.00
75.00 |
NA |
NA
Acute
| ADR pot (mg/kg/day)
0.82 (
NA
1 day J
71.80 |
129.00
Figure 3-18. Lakes Results Page - Fish Ingestion Exposure Estimates
Exposure Types
Potential Lifetime Average Daily Dose (LADDPOT) — from ingestion of fish tissue; calculated
to represent chronic exposures to fish over a lifetime. These doses are generally used for cancer
calculations.
• Potential Lifetime Average Daily Concentration (LADCPOT) — of the chemical of concern in
ingested fish tissue; calculated to represent chronic lifetime concentrations. These concentrations
are generally used for cancer calculations.
Potential Acute Dose Rate (ADRPOT) — from ingestion of fish tissue; normalized over a shorter
time period (e.g., 1 day).
Exposure Factors
• Exposure Duration (ED) — number of years a resident consumes contaminated fish
E-FAST V2.0 uses a default value of 30 years; see Table 3-2.
Averaging Time (AT) — period of time over which exposures are averaged.
Body Weight (BW) — mean body weight for the population being assessed.
Fish Ingestion Rate (IRnsh) — used for calculating acute and chronic exposures.
Estimation of Potential Doses via Fish Ingestion
To estimate how much of a given chemical a person will ingest through eating fish, E-FAST V2.0
uses Equations 3-8 through 3-10 (See Section 3.1.4.3). These equations convert an estimated surface
water concentration to a fish ingestion exposure estimate. The distinction between acute and chronic fish
3-35
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ingestion is made on the basis of daily ingestion rate. The mean long-term fish ingestion rate is used to
calculate chronic exposures and the mean serving size is used to calculate acute fish ingestion exposures
for adults.
3.1.6.3 Lakes Results Page - Endangered Species
The Endangered Species tab presents the endangered species known (or possible) to exist in the
vicinity of lakes, bays, estuaries, and oceans that receive wastewater discharges containing the chemical
of concern. The Endangered Species tab in the Lakes Results page is identical to the Endangered Species
tab in the Rivers Results page (Figure 3-13). The location of endangered species is correlated with the
facility location via FIPS State and county codes. The endangered species information is presented in six
columns and includes common name, county and State, taxonomic group (e.g., mammals, birds, fish,
plants, reptiles, amphibians, clams, etc.), listing action (listing, proposed, delisting), and known
occurrence. The data were obtained from EPA's Endangered Species Protection Program (ESPP)
Databases (U.S. EPA, 2004). The ESPP is a cooperative effort between the U.S. Fish and Wildlife
Service (FWS), EPA Regions, States, and pesticide users. ESPP is located in the Field and External
Affairs Division (FEAD) of the Office of Pesticide Programs (OPP).
3.1.7 Landfill Results Page
Figure 3-19 shows an example Landfill Results page. The box in the upper left-hand corner
shows all of the release activities that included discharges to landfills; you can click on any release
activity to view the results for that activity. The "Print Page" button in the lower right-hand corner may
be used to generate a hard copy of the data on the screen. The following are short descriptions of the
fields listed in the upper half of this page.
E-FAST V2.0 uses a simple conservative method for estimating groundwater concentrations that
may result from chemical releases to landfills. These releases may be in the form of waste material from
manufacturing, processing, or commercial activities, or wastewater treatment plant sludge that contains
the chemical and is placed in a landfill.
3-36
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17 Screening Level Results
^JnjxJ
Close |
Environmental Releases | Rivets | SIC Code | Lakes | Inhalation Landfill | PDM Site | PDM SIC Code |
Exposure Estimates From Groundwater Ingestion
7 Help ;|
Chem ID/Rel tt
1123502.2
1123502.3
I
Release Activity: |Manufacturing
Exposed Population: |Adult
Migration Descriptor: jSlow
Adsorption to WWT Sludge: |
Dunking Water Treatment: |
Non-Sludge Landfill Release
Landfilled Sludge
ttDays of Non-Sludge Release
11.00 % ttDays of Sludge Release
tt Sites
9.00 %
100.00 kg/site/day
4.40 kg/site/day
100.00 days
200.00 days
1.00
Landfill Exposure Estimates
Exposure Types
Results [ ED (yrs)
AT (yrs)
BW (kg)
| IRdrink (L/day)
Cancer
| LAD D pot (mg/kg/day) |
2.0GE-03 30.00 |
75.00
71.80
1.40
[ LADCpot (mg/L)
0.11 | 30.00 |
75.00
NA
NA
t Page |
Landfill Comments
Figure 3-19. Landfill Results Page - Landfill Exposure Estimates
The following are short descriptions of the fields in this page:
• Release Activity — can be manufacturing, processing, industrial use, or other. This was entered
in a text field on the left-hand side of the General Release Information page (Figure 3-2).
Exposed Population — can be adults, youths 13 to 19 years, children 6 to 12 years, children 3 to
5 years, infants 1 to 2 years, or infants less than one year old. This was entered on the Screening
Level Main page (Figure 3-1).
Migration Descriptor —an expression of the chemical's tendency to migrate from the waste
being disposed of in the landfill to surrounding soil, and eventually to groundwater. The
migration descriptors used by E-FAST V2.0 are negligible, negligible to slow, slow, moderate,
and rapid; a rating of "negligible" indicates that the chemical does not reach groundwater. The
migration descriptor should be selected on the basis of physical-chemical parameters such as the
log of the organic carbon/water partition coefficient (log K, ,c), the log of the n-octanol/water
partition coefficient (log KqW), the expected leachability of the chemical from the type of waste
being disposed, and the reactivity of the chemical, which includes transformation processes such
as biodegradation and hydrolysis (as applicable). A discussion of the E-FAST V2.0 default
descriptor selection method is presented later in this section. This method may be useful when it
is known that reactivity is not a factor controlling migration, and a measured log Koc value is
available or it is known that Koc estimation methods yield reliable predictions. The migration
descriptor was entered in the PChem/Fate Inputs screen (Figure 2-1).
Adsorption to Wastewater Treatment (WWT) Sludge — percentage of chemical adsorbed to
sludge during wastewater treatment. This value was entered in the PChem/Fate Inputs screen
(Figure 2-1).
3-37
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Drinking Water Treatment Removal — removal percentage, which is based on the physical-
chemical characteristics of the chemical and the expected efficiency of unit treatment processes at
the drinking water treatment facility. This value was entered in the PChem/Fate Inputs Screen
(Figure 2-1).
Number of Sites— number of landfill release sites. This value was entered in a number field on
the left-hand side of the General Release Information page (Figure 3-2).
Non-Sludge Landfill Release — the per site daily release amount and release days of chemical
wastes (excluding landfilled wastewater treatment sludge) to a landfill. These values were entered
in the General Release Information Page (Figure 3-2b).
Landfilled Sludge — the per site daily release amount and release days of chemical in
contaminated wastewater treatment sludge that is landfilled. If you have specified a surface water
release and a percent adsorption to wastewater releases in the PChem/Fate Inputs screen (Figure 2-
1), E-FAST V2.0 will have calculated a sludge release for you. These values were entered in the
General Release Information Page (Figure 3-2b).If you have specified non-sludge landfill and
landfilled sludge as releases in the same release activity entry screen in Figure 3-2b, E-FAST V2.0
assumes the per site amounts are landfilled together at one location; non-sludge and sludge
releases from one release site that are landfilled at different locations should be entered on separate
release activity screens.
The lower half of the page presents the chronic exposure doses for individuals who ingest
groundwater contaminated by landfill releases containing the chemical of concern. The first column,
"Exposure Types," lists two different measurements of exposure. To the right of each, under the "Results"
heading, is the corresponding exposure value. The subsequent columns contain exposure factors that were
entered in the Exposure Factors page (See Section 3.1.2). The exposure types and exposure factors are
defined below.
Exposure Types
• Potential Lifetime Average Daily Dose (LADDPOT) — from ingestion of groundwater
contaminated by landfill releases; calculated to represent chronic exposure over a lifetime. These
doses are generally used for cancer calculations.
Potential Lifetime Average Daily Concentration (LADCPOT) — in groundwater contaminated
by landfill releases; calculated to represent chronic lifetime concentration. These concentrations
are generally used for cancer calculations.
Potential Acute Dose Rate (ADRP0T) is not calculated because the algorithms used in the
estimation method calculate long-term average groundwater concentrations rather than short-term acute
concentrations (see below).
Exposure Factors
• Exposure Duration (ED) — number of years a resident drinks contaminated water. E-FAST V2.0
uses a default value of 30 years; see Table 3-2.
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Exposure Frequency (EF)— number of days per year a resident drinks contaminated water.
E-FAST V2.0 uses a default value of 365 days/year.
Averaging Time (AT) — period of time over which exposures are averaged.
Body Weight (BW) — mean body weight for the population being assessed.
Estimation of Groundwater Exposure Concentrations from Releases to Landfills
Site-specific estimation of groundwater (drinking water) exposure from landfills requires
information on climate, soil, groundwater flow direction, and location of receptor drinking water wells.
Because this level of information is commonly not available for screening-level estimates, E-FAST V2.0
uses a simple, conservative, generic method developed by EPA (U.S. EPA, 1987a). The only chemical-
specific parameter required is the log Koc, and it is assumed that a reliable value (measured or estimated)
exists. It is also assumed that the substance does not degrade abiotically or biologically at a rate sufficient
to significantly affect its potential to reach ground water.
This method is based on studies that modeled the groundwater concentrations that resulted from
the landfill of hypothetical nonvolatile compounds (i.e., Henry's law constant < 1E-05 atm-m3/mol) of
varying soil sorption characteristics (i.e., log Koc values ranging from 0 to 4.5) in soil types with different
organic carbon contents and groundwater hydraulic characteristics (GSC, 1987; U.S. EPA, 1987a). The
transport of the chemicals through the soil and groundwater was modeled using the SESOIL and AT123D
models, respectively. The loading of chemicals in a 1-hectare landfill was assumed to be 1,000 kg/year for
10 years. The distance to groundwater was assumed to be 8 meters, and the depth of a drinking water well
200 meters from the edge of the landfill was set at 20 meters.
EPA used the results of these studies to develop a conservative method for predicting groundwater
exposures from landfill disposals by assigning migration descriptors based on log Koc values and the
maximum long-term (>70 year) average groundwater concentrations associated with those Koc values, as
follows:
Groundwater concentration (GWC)
Migration Descriptor Log K.... (mg/L per kg release)
Negligible - no migration None
Negligible to slow >4.5 3.21E-6
Slow <4.5 to 3.5 2.67E-5
Moderate <3.5 to 2.5 5.95E-5
Rapid <2.5 7.55E-5
Estimation of Groundwater Potential Doses from Releases to Landfills
To estimate how much of a given chemical a person will ingest through groundwater (drinking
water), E-FAST V2.0 uses the equations presented below. These equations convert an annual chemical
release and its estimated groundwater concentration (from the preceding section) to a drinking water
exposure estimate. The release amount is multiplied by the groundwater concentration (per kg release),
the removal rate (if any) of the chemical during treatment of the drinking water, the estimated drinking
water ingestion rate, the exposure frequency, and the exposure duration. This product is then divided by
body weight and averaging time to yield the exposure dose.
LFR x GWC x
LADDPOT — ¦
1 -
DWT
100
x IRdw x EF x ED
(Eq. 3-12)
BW x AT x CF1
3-39
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where:
LADDpoi
Potential Lifetime Average Daily Dose (mg/kg/day)
LADCpoi
Potential Lifetime Average Daily Concentration in drinking water (mg/L)
LFR
Chemical release rate to landfill per site (kg/yr)
GWC
Groundwater concentration (mg/L per kg release/yr)
' Rjw
Drinking water intake rate (L/day)
BW
Body weight (kg)
DWT
Removal during drinking water treatment (percent)
ED
Exposure duration (years)
AT
Averaging time (years)
EF
Exposure frequency (days/yr)
CF1
Conversion factor (365 days/yr)
3.1.8 Inhalation Results Page
As introduced in Section 3.1.1.3, E-FAST V2.0 uses EPA's SCREEN3 Model for estimating
ambient air concentrations from stack and fugitive releases. Stack releases include but are not limited to
incineration; an example of fugitive release is untreated local exhaust at ambient temperature. An
example Inhalation Results page is shown in Figure 3-20. The box in the upper left-hand corner shows all
of the fugitive air and stack release activities; you can click on any release activity to view the results for
that activity. The following are short descriptions of the fields listed in the upper half of this page.
• Release Activity — can be manufacturing, processing, industrial use, or other. This was entered
in a text field on the left-hand side of the General Release Information page (Figure 3-2).
Exposed Population — can be adults, youths 13 to 19 years, children 6 to 12 years, children 3 to
5 years, infants 1 to 2 years, or infants less than one year old. This was entered on the Screening
Level Main page (Figure 3-1).
Number of Sites — number of fugitive and/or stack release sites. This was entered in a number
field on the left-hand side of the General Release Information page (Figure 3-2).
Per Site Fugitive Release — total site release of fugitive emissions, presented in units of
kg/site/day.
Release Days (fugitive) — number of days per year that the chemical is released to the air via
fugitive emissions. This was entered in a number field on the right-hand side of the General
Release Information page (Figure 3-2c).
Per Site Stack Release — total site release of stack emissions, presented in units of kg/site/day.
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Release Days (stack) — number of days per year that the chemical is released to the air via stack
emissions. This was entered in a number field on the right-hand side of the General Release
Information page (Figure 3-2c).
In addition to these fields, the top portion of the Inhalation results page displays a "Print Page" button that
may be used to generate a hard copy of the data on the screen. The hard copy includes the data in all of
the tabs in the lower portion of the screen (Inhalation Exposure Estimates, Release Information,
Meteorological/Terrain and Downwash Information, and SCREEN3 Model Results), so there is no need
to click the "Print Page" button for each of these tabs.
Screening Level Results
Environmental Releases | Rivers ] SIC Code ] Lakes Inhalation j Landfill ] PDM Site ] PDM SIC Code ]
I Inhalation Exposure Estimates (Combined Fugitive and Stack)
7 Help

Chem D/Re tt
Release Activity
Exposed Population
Number of Sites
] Manufacturing
|Adult
Per Site Fugitive Release: |
Release Days (Fugitive): [~~
Per Site Stack Release: f~
1B.00 kg/site/day
100.00
2,000.00 kg/site/day
Release Days (Stack): [~~
Print Page
Inhalation Exposure Estimates | Release Information | Meterological/Terrain and Downwash Information | Screen3 Model Results
Fugitive Inhalation Exposure Estimates Stack Inhalation Exposure Estimates j
Stack Inhalation Exposure Estimates
Exposure Types
Results |
ED (yrs) j
AT (yrs)
BW (kg)
1 IR (m3/hr)
Cancer
| LAD D pot (mg/kg/day) |
3.30E-03 |
30.00 |
75.00
71.80
0.55
| LADCpot (mg/m3)
1.80E-02 |
30.00 |
75.00
NA
NA
Acute
| ADR pot (mg/kg/day) [
0.38 |
NA |
1 day
71.80
0.55
Inhalation Comments:
Figure 3-20. Inhalation Results Page - Inhalation Exposure Estimates
Three tabs located in the lower half of the page allow you to view Inhalation Exposure Estimates,
Release Information, and Meteorological/Terrain and Downwash Information, and SCREEN3 Model
Results.
3.1.8.1 Inhalation Results Page - Inhalation Exposure Estimates
The Inhalation Exposure Estimates tab (Figure 3-20) presents the acute and chronic exposure
doses for individuals who breathe the air containing the chemical of concern. This tab contains two sub-
tabs displaying exposure estimates for fugitive and stack releases. In each sub-tab, the first column,
"Exposure Types," lists three different measurements of exposure. To the nght of each, under the
"Results" heading, is the corresponding exposure value. The subsequent columns contain exposure
factors that were entered in the Exposure Factors page (See Section 3.1.2). The exposure types and
exposure factors are defined below.
3-41
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Exposure Types
Potential Lifetime Average Daily Dose (LADDPOT) — from inhalation of stack and fugitive air
emissions; calculated to represent chronic exposures over a lifetime. These doses are generally
used for cancer calculations.
• Potential Lifetime Average Daily Concentration (LADCPOT) — from inhalation of the
chemical of concern in stack and fugitive air emissions; calculated to represent chronic lifetime
concentrations. These concentrations are generally used for cancer calculations.
Potential Acute Dose Rate (ADRPOX) — from inhalation of stack and fugitive air emissions;
normalized over a shorter time period (e.g., 1 day).
Exposure Factors
• Exposure Duration (ED) — number of years the resident breathes contaminated air.
E-FAST V2.0 uses a default value of 30 years; see Table 3-2.
Averaging Time (AT) — period of time over which exposures are averaged.
Body Weight (BW) — mean body weight for the population being assessed.
Inhalation Rate (InhR) — used for calculating acute and chronic exposures.
Estimation of Ambient Air Exposure Concentrations
E-FAST V2.0 uses EPA's SCREEN3 air dispersion model to estimate air concentrations. This
section describes the approach used to develop the fate and transport modeling system for residential
(outdoor) air exposures. It also includes an overview of the principles of ambient air dispersion modeling
and a discussion of the input parameters, the default values used in E-FAST V2.0, and the assumptions
needed to perform air dispersion modeling.
a) General Overview of Air Dispersion Models
Air quality models have become the primary analytical tool for assessing the effects of point
sources on air quality. A point source is an emission that emanates from a specific point, such as a
smokestack or vent. The modeling methods used are considered to be applicable for assessing impacts of
a source from the facility fence line out to a 50-km radius of the source to be modeled (U.S. EPA, 1992a).
These models use mathematical equations to simulate the rise of a plume from a source and the
subsequent horizontal and vertical dispersion affected by wind, temperatures, terrain, and other
environmental factors (Turner, 1994). Gaussian models are the most widely used techniques for
estimating the impact of nonreactive pollutants (U.S. EPA, 1987b). These models use the Gaussian
distribution to describe crosswind and vertical distributions that are the result of wind and other factors
that produce mixing (Turner, 1994). According to Turner (1994), the basic Gaussian dispersion equation
simulates the 3-dimensional behavior of pollutants in the atmosphere:
X = QVD/(2Ti;usayc^e^[-l/2((^ -h^/c^2]
+£ [exp -l/2((2 -he-2hk)iof~\
TiZll 1J
(Eq. 3-14)
3-42
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where:
Concentration (g/m3)
Emission rate (g/s)
Vertical term
Dispersion term
Stack height wind speed (m/s)
Lateral dispersion parameter (m)
Vertical dispersion parameter (m)
Receptor height above ground (m)
Plume centerline height (m)
Mixing height (m)
Summation limit for multiple reflections of plume off of the ground and elevated
inversion, usually < 4
See Sections 1.1.6 and 1.1.7 of the User's Guide of the ISC3 Dispersion Model Vol. 2 for more
information (U.S. EPA, 1995b).
The fate and transport modeling system depends on you to provide data which describe the local
situation so the model can predict likely resulting concentrations at a residence some distance from the
facility. It is necessary to have quantitative information about the sources to conduct air dispersion
modeling. Screening models need less information than more sophisticated models. The main inputs
include the following parameters for stack emissions:
Source emission rate
Stack height
Inside stack diameter
Exhaust gas exit velocity
Exhaust gas exit temperature
Dimensions of structures near each source
Land use near the modeled facility
Terrain features near the facility
Distance to receptor
Receptor height
and the following parameters for fugitive emissions:
Source emission rate
Release height
Length of larger side
Length of smaller side
Wind Direction Search Option
Land use near the modeled facility
Terrain features near the facility
Distance to receptor
Receptor height
SCREEN3 is an EPA screening-level system that uses a Gaussian plume model, incorporating
source-related factors and meteorological conditions to estimate the ambient pollutant concentration (U.S.
X
Q
V
D
us
Oy
Zr
he
Zi
k
3-43
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EPA, 1995a). The model requires relatively straightforward facility-specific input data on stack,
meteorological conditions, and terrain. The main advantages of SCREEN3 are that it is simple to use and
does not require much data (default values are provided for most parameters). SCREEN3 performs
single-source calculations, estimating the maximum 1-hour average concentrations at prespecified distances.
(Note: This value is not appropriate for assessing potential health impacts of long-term, i.e., chronic,
exposure. According to EPA (1992b), risk assessment for chronic health effects should be based on the
maximum annual concentration for a representative exposure concentration. The convention used in
E-FAST V2.0 (based on general experience with elevated point sources) is to approximate the maximum
annual average concentration by multiplying the 1-hour maximum average concentration by a generic
conversion factor. (U.S. EPA, 1992b))
b) Input Parameters, Default Values, and Assumptions for SCREEN3 Dispersion Modeling
E-FAST V2.0 incorporates SCREEN3 by linking the output of one calculation (e.g., emission rate
estimates) to the input of the subsequent model (e.g., air dispersion) and a post-processing program that
incorporates SCREEN3's predicted concentrations into E-FAST V2.0's potential dose calculations. The
user interface prompts you for the input parameters SCREEN3 needs to perform the dispersion
calculations that result in estimated air concentrations at a residence at a given distance from the facility.
E-FAST V2.0 provides default input values for all of these input parameters, except emission rate, which
is generated by E-FAST V2.0 based on the release amount you entered in the ambient air section of the
General Release Information Page (See Section 3.1.1.3). The main input parameters for stack emissions
include:
Emission Rate (g/s), which is generated by E-FAST V2.0, based on user inputs
Stack Height (m)
Inside Stack Diameter (m)
Stack Gas Exit Velocity (m/s)
Stack Gas Temperature (K)
Ambient Temperature (K)
While E-FAST V2.0 uses the point source algorithms in SCREEN3 to generate emission
concentrations for stack emissions, E-FAST V2.0 uses the area source algorithms in SCREEN3 to model
downwind concentrations for fugitive emissions. Unlike stack emissions that exit a facility at a single
stack or point, fugitive emissions exit a facility through cracks, vents, or openings; this type of emission is
modeled as an area release. The main input parameters for fugitive emissions include:
Emission Rate (g/m2-s), which is generated by E-FAST V2.0, based on user inputs
Release Height (m)
Length of Release Opening (m)
Width of Release Opening (m)
SCREEN3 also requires the distance to the residence, meteorological conditions, the height and
usage of the surrounding terrain, downwash conditions (for stack releases only), and other related
parameters. Prior to beginning any model calculations, you can review the default values for their
appropriateness to your model run (See Table 3-1, Section 3.1.1.3). If you choose not to accept a default
value for any parameter, you can enter a site-specific value. The user interface provides logical
constraints on the range of possible values you can enter.
3-44
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Below are several assumptions made for air dispersion modeling in E-FAST V2.0:
Ambient Transformation — SCREEN3 and E-FAST V2.0 do not account for chemical
reactions (transformation) in the atmosphere. This is a conservative assumption because the
duration that emitted chemicals will be in the atmosphere before reaching the potential receptors
(i.e., nearby residents) is relatively short.
Constant Emission Rate — The air dispersion calculations performed by SCREEN3 rely on a
source emission rate for each pollutant, in g/s or g/m2-s. These emissions are assumed to be
continuous and the rate not variable overtime. Because of these assumptions, the emission rate
inputs must be adjusted according to the desired outputs, which for E-FAST V2.0 are 24-hour and
annual maximum average concentrations. For example, a 100 kg per day release that occurred two
days per year would have a source emission rate based on 100 kg/d for the 24-hour concentration
calculation, but the source emission rate for the annual maximum calculation would be calculated
from the total amount emitted per year (200 kg). The source emission rate data are provided by E-
FAST V2.0 from the earlier calculations in the ambient air section of the General Release
Information page (Figure 3-2). These data are automatically input to the air dispersion modeling
of E-FAST V2.0.
Single Point Emissions — E-FAST V2.0 assumes that all stack emissions from a given facility
are released from a single stack. E-FAST V2.0 treats fugitive emissions in a similar fashion,
however the user can adjust the size of the release area so that it encompasses all of the fugitive
releases. SCREEN3 cannot explicitly determine impacts from multiple sources; however, it can
provide a conservative estimate for the downwind concentration if the emissions are merged into
a single representative stack. (Note: SCREEN3 may provide an unacceptably high estimate for
the downwind concentration using a "representative" stack, if the stacks are located more than
100m apart, or the stack parameters differ more than 20 percent.)
To determine the parameter for the "representative" stack of multiple stacks, a merged stack
parameter is calculated for each individual stack using the following equation:
hsx
M =
ML
Q
\D?V.
XTS
(Eq. 3-15)
where:
M
Merged stack parameter (m4K/g)
hs
Stack height (m)
Ds
Inside stack diameter (m)
vs
Stack exit gas velocity (m/s)
Ts
Stack gas exit temperature (K)
Q
Pollutant emission rate (g/s)
Screen 3 inputs: use the stack with the lowest value of M as the representative stack and the sum
of the emission rates from all of the stacks as the emission rate from the representative stack (U.S. EPA,
1992b).
3-45
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Default Model Parameters
Table 3-1 in Section 3.1.1.3 shows the default values provided by E-FAST V2.0 for
stack/incinerator releases and for fugitive/vent releases. Several other parameters and the considerations
in selecting appropriate values for them require more extensive discussion and are provided below. These
parameters influence the way the model simulates stability and turbulence in the atmosphere.
Meteorological Conditions — With respect to information needed by SCREEN3, stability and
wind speed are the two most important parameters of meteorological conditions that affect
ambient pollutant concentrations emitted from an elevated stack. In a stable atmospheric
environment, the plume is trapped at a certain height or even descends, resulting in a relatively
high concentration. In an unstable atmospheric environment, the plume rises to a higher level by
momentum and buoyancy forces. Horizontal winds transport pollutants away from the source and
dilute ambient concentrations. The effect of horizontal wind speed is relatively straightforward:
doubling the wind speed cuts concentrations in half. Modeling dispersion is easiest when winds
are from one direction and of consistent speed, and when the terrain is flat and uninterrupted (as
in a rural area).
For simple elevated or flat-terrain screening, you have three choices of meteorological conditions:
(1) full meteorological description, including all stability classes and wind speeds; (2)
specification of a single stability class; and (3) specification of both stability class and wind
speed. Full meteorology is recommended for a combination of stability and wind speed that will
result in maximum ground-level concentrations. If you have particular meteorological conditions
of concern, specify either stability only or both stability and wind speed for SCREEN3 modeling.
Stability classes are indicators of atmospheric turbulence. The stability category depends on static
stability (related to the change in temperature with height), thermal turbulence (caused by heating
of the air at ground level), and mechanical turbulence (a function of wind speed and surface
roughness). See Screening Procedures for Estimating the Air Quality Impact of Stationary
Sources, Revised (U.S. EPA. 1992b) and SCREEN3 User's Guide (U.S. EPA 1995a) for more
detailed information.
Surrounding Land Use — This classification has a significant effect on estimates of downwind
concentrations. The default value is rural, but you can modify this classification in the user
interface. The selection of urban or rural dramatically affects the estimate of concentrations by
giving a different wind speed profile at the same stability category. If more than 50 percent of an
area 3 km around the source is of land use types heavy or medium industrial, commercial or
multi-family residential, the site is deemed to be in an urban setting. Also, if the population
density within a 3 km radius around the source is greater than 750 people per square km, the
urban mode should be selected (U.S. EPA, 1995a, 1997b).
Terrain — Air quality models are most accurate when simulating long-term averages in areas
with relatively simple topography (U.S. EPA, 1987b). Terrain sometimes significantly affects
ambient ground-level pollutant concentrations through its effects on plume behavior. The
important topographic features to note are the location and height of the elevated terrain.
SCREEN3 uses two types of terrain: simple or complex. Simple terrain is considered to be an
area where terrain features are all lower in elevation than the top of the stack of the source(s) in
question. Complex terrain is defined as terrain exceeding the height of the stack being modeled.
3-46
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If terrain height is higher than stack height, the modeling techniques required to simulate such a
situation become more demanding. Because of the potential for providing inappropriate
information in such a circumstance, only the simple terrain option of SCREEN3 has been
incorporated into E-FAST V2.0.
Conversion of 1-hour Maximum Concentration to 24-hour and Annual Maximum Average
Concentrations — The standard output from SCREEN3 is a 1-hour maximum average
concentration. As stated in Section 3.1.1.3, E-FAST V2.0 does independent SCREEN3 model
runs for use in calculating the desired 24-hour and annual maximum average concentrations.
E-FAST V2.0 then converts these values to 24-hour and annual maximum concentrations by
multiplying the SCREEN3 calculations by the following conservative conversion factors (U.S.
EPA, 1992b):

Stack
(point source)
Fugitive
(area source)
24-hour maximum average
0.4
1
Annual maximum average
0.08
0.08
These conversion factors were developed by the EPA Office of Air Quality Planning and
Standards (U.S. EPA, 1992b). They are intended to be used for a general case with a degree of
conservatism to ensure that the annual maximum concentration will not be underestimated.
Estimation of Ambient Air Potential Doses
As described in the previous section, SCREEN3 predicts the air concentration for the residential
scenario based on emission rates, stack data, terrain, meteorological conditions, and other related
information. Exposure via inhalation is estimated using the equations below:
u.t ^ ^ innis. EjLJ l fE 3 1
ADRp0T = ~^T for stack (point source) releases (t,C]. ")
AAC24 x InhR X ED x CF1
ADRpQT = BW ~AT for fugitive (area source) releases (Eq. 3-17)
LADDPOT =
0.08 x AAC.„ x InhR x EF x ED x CF1
yr
BW x AT x CF2
(Eq. 3-18)
LADCp0T —
0.08 x AACy, x ED x CF1
AT
(Eq. 3-19)
where:
ADRP0T
LADDpoi
LADCpoi
Potential Acute Dose Rate (mg/kg/day)
Potential Lifetime Average Daily Dose (mg/kg/day)
Potential Lifetime Average Daily Concentration (mg/m3)
3-47
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InhR
EF
ED
BW
AT
CF1
CF2
aac24
AACy,.
24-Hour Maximum Average Ambient Air Concentration (fig/nr')
Annual Maximum Average Air Concentration (|ig/m3)
Inhalation rate (m3/day, equal to m3/hr x 24 hr/day)
Exposure frequency (365 days/year; see explanation below.)
Exposure duration (years for LADCP0T and LADDP0T, day for ADRP0T)
Body weight (kg)
Averaging time (years for LADCP0T and LADDP0T, day for ADRP0T)
Conversion factor (10 3 mg/(.ig)
Conversion factor (365 days/year)
The value of AAC24 in Equations 3-16 and 3-17 is calculated by running SCREEN3 using the emission
rate occurring over the course of one day. Forthe AACyj. used in Equations 3-18 and 3-19, the emission
rate input for SCREEN3 is calculated by taking the amount released in one year, regardless of the number
of release days, and dividing the annual release by 365 days. Therefore, in the above equation, the
exposure frequency (EF) is 365 days per year. Because of this difference in emission rates for daily and
annual dose calculations, SCREEN3 is run twice for each fugitive release and twice for each stack
release. The results of the SCREEN3 model runs are presented with the inhalation results, as described in
Section 3.1.8.4. The units of AAC24 and AACyr are presented as (ig/m3 to be consistent with the stand-
alone SCREEN3 model that is familiar to many users of E-FAST V2.0.
3.1.8.2 Inhalation Results Page-Release Information.
The Release Information tab (Figure 3-21) presents the release information inputs that were
entered into SCREEN3. These inputs include Stack Height (m), Inside Stack Diameter (m), Stack Gas
Exit Velocity (m/s), Stack Gas Temperature (K), Release Height (m), Length of Release Opening (m),
and Width of Release Opening (m). All of these parameters are described in detail in Section 3.1.8.1. In
addition, the Pretreatment Release (kg/site/day) and Emissions Removal (%) as entered on the General
Release Information page (Figure 3-2c) and the PChem/Fate Inputs screen (Figure 2-1) are shown.
3-48
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17 Screening Level Results
Environmental Releases | Rivers | SIC Code | Lakes Inhalation j Landfill | PDM Site | PDM SIC Code |
^^91 Inhalation Exposure Estimates (Combined Fugitive and Stack)
7 Help

Release Information (Pre-treatment)

s
ack Parameter Data
Fugitive Parameter Data
Stack Height:
10.00
m
Release Height:
3.00
m
Inside Stack Diameter:
0.10
m
Length of Release Opening:
10.00
m
Stack Gas Exit Velocity:
0.10
m/sec
Width of Release Opening:!
10.00
m
Stack Gas Temperature:
293.00
K
Pre-treatment release: |
16.00
kg/site/day
Pre-treatment release:
2,000.00
kg/site/day
X Removal: |
20.00
X
X Removal:
90.00
X

Inhalation Comments:
Figure 3-21. Inhalation Results Page - Release Information.
3.1.8.3 Inhalation Results Page - Meteorological/Terrain and Downwash Information
The Meteorological/Terrain and Downwash Information tab (Figure 3-22) presents the
meteorological, terrain, and downwash information inputs that were entered into SCREEN3. These
inputs include Surrounding Land Use, Terrain Height (m), Distance to Residence of Interest (m), and
Meteorological Class (including Stability Class and Wind Speed, if applicable). In addition, the Facility
Length (m), Facility Width (m), and Facility Height (m) will be presented, if applicable. All of these
parameters are described in detail in Section 3.1.8.1.
3-49
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17 Screening Level Results

Environmental Releases | Rivers | SIC Code | Lakes Inhalation j Landfill | PDM Site | PDM SIC Code |
7 Help |
Inhalation Exposure Estimates (Combined Fugitive and Stack)
Chem D/Re tt
Release Activity
Exposed Population
Number of Sites
[Manufacturing-
|Adult
Per Site Fugitive Release: |~~
Release Days (Fugitive): |
Per Site Stack Release: |
16.00 kg/site/day
100.00
2,000.00 kg/site/day
Release Days (Stack): |~~
t Page |
Inhalation Exposure Estimates | Release Information Meterological/Terrain and Downwash Information | Screen3 Model Results
Meteorological/Terrain and Downwash Information
Surrounding Land Use: [Rural
Terrain Height: | 0.00 m
Distance to Residence of Interest: | 100.00 m
Meteorology Class: [Full
Stability Class: |NA
Wind Speed: | NA
Facility Length: [ 100.00 m
Facility Width: | 100.00 m
Facility Height: | 10.00 m
Inhalation Comments:
Figure 3-22. Inhalation Results Page - Meteorological/Terrain and
Downwash Information
3.1.8.4 Inhalation Results Page - SCREENS Model Results
The SCREEN3 Model Results tab (Figure 3-23) presents the results of the SCREEN3 model runs.
Results are presented for 24-hour average concentration and annual average concentration derived from
stack and fugitive emissions. These are the AAC24 and AACyr values used in Equations 3-16, 3-17, 3-18,
and 3-19. Note that the units are (ig/m3, which is consistent with the stand-alone SCREEN3 model.
3-50
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tf Screening Level Results
BBB
Environmental Releases | Rivers | SIC Code | Lakes Inhalation j Landfill ] PDM Site | PDM SIC Code ]
Help |
Inhalation Exposure Estimates (Combined Fugitive and Stack)

Release Activity
Exposed Population
Number of Sites
{Manufacturing
Per Site Fugitive Release
Release Days (Fugitive]
Per Site Stack Release
| 1G.00 kg/site/day
Chem ID/Rel 8
(Adult
I 100. GO

1
] 2.000.00 kg/sile/day
Print Page |
Release Days (Stack]
| 40.00
Inhalation Exposure Estimates ] Release Information | Meterological/Terrain and Downwash Information Screen3 Model Results |
Screen3 Model Results
Stack Fugitive
Max Annual Avg Air Concentration: |
44.90 |
38.30
ug/m*
Max 24 hr Avg Air Concentration: |
2,050.00 J~
1,750.00
ug/rn®
Inhalation Comments:
Figure 3-23. Inhalation Results Page - SCREEN3 Model Results
3.1.9 PDM Site-Specific Results Page
Running PDM is optional, as discussed in Section 3.1.1.1. In E-FAST V2.0, PDM predicts the
number of days per year a chemical's COC in an ambient water body will be exceeded by the discharge
from a facility. PDM analyses can be performed on reaches with measured flow data or reaches with only
estimated flow values. An example of the PDM Site-Specific Results page is shown in Figure 3-24.
The model is based on the mathematical derivation presented by Di Toro (1984). A simple mass
balance approach forms the basis of the model; however, the input variables are not single point
estimates. In reality, these variables are not constant; streams follow a highly variable seasonal flow
pattern and numerous variables in a manufacturing process can affect the chemical concentration and flow
rate of the effluent. PDM uses probability distributions as inputs and calculates the resulting probability
distribution of the concentration in the stream. See Appendix C for a description of the statistical
framework of PDM.
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17 Screening Level Results
Environmental Releases | Rivers | SIC Code | Lakes | Inhalation | Landfill PDM Site | PDM SIC Code |
PDM Site-Specific Page
nm3
Help
Chern D/Re tt
NPDES Number
Release Activity
Facility Name
Facility Location
Reach Number
Reach Name
[Manufacturing""
MALDEN STP
MALDENILG1337
107130001033
|big bureau cr
Facility on Reach? <•" Yes C No C Unk.
Gaging Station: 105556500
Period of Record: (01/01/66 - 09/29/88
Number of Observations: |
0309
Note: this is an active site.
Discharge Type
WWT Removal
Release Days
Concentration of Concern
Pretreatment Release
Post-treatment Release
Mean Stream Flow
Low Stream Flow
Effluent Flow
Direct
25.00 %
200.00 days/yr
100.00 ug/L
40.00 kg/site/day
30.00 kg/site/day
178.56 MLD
12.23 MLD
8.00E 02 MLD
PDM Site-Specific Estimates
t Page |
CDC (ug/L] T
tt Days exceeded:
1 yti r
X year exceeded: |~~
35 62 |~~
Figure 3-24. PDM Site-Specific Results Page
To run PDM, select "Include PDM run" on the General Release Information page (Figure 3-2a).
(Selecting "Average PDM Analysis (SIC Code)" or "High-end PDM Analysis (SIC Code)" under "Select
PDM Analysis" will yield the same results when performing a site-specific analysis.) On the Select a
Facility screen (Figure 3-3), PDM uses the selected NPDES number to determine if the reach has a USGS
gaging station (i.e., measured flow data are available). If the reach has a gaging station, the ranked
measured daily flow values are used to determine the frequency of exceedence. If only estimated flow
data are available, the program estimates the frequency of exceedence using a watershed-specific
relationship between mean flow, 7Q10 flow, and the streamflow coefficients of variation for gaged
streams in the watershed.
Using information entered in the PChem/Fate Inputs screen (Figure 2-1) and on the General
Release Information page, PDM estimates the number of days per year and the percentage of the year the
COC was exceeded. The Chemical ID/Release Number box on the left hand side of the page can be
scrolled to show all the stored site-specific PDM results for all surface water releases analyzed using the
site-specific surface water release scenario. The following are short descriptions of the fields that appear
on the PDM Site-Specific Results page:
NPDES Number — extracted from the E-FAST V2.0 database when searching for a facility
during the data entry procedure (See Section 3.1.1.1).
• Release Activity — can be manufacturing, processing, industrial use, or other. This was entered
in a text field on the left-hand side of the General Release Information page (Figure 3-2a).
Facility Name, Location, Reach Number, Reach Name — information on the discharging
facility extracted from the E-FAST V2.0 database when searching for a facility during the data
entry procedure (See Section 3.1.1.1).
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Facility on Reach? — indicates whether the facility discharges to the identified reach, discharges
to a tributary stream, or if the discharge point is unknown.
Discharge Type — indicates whether the facility is a direct discharger that discharges treated
wastewater directly to a surface water body or an indirect discharger that discharges wastewater
to a POTW for treatment.
• Wastewater Treatment (WWT) Removal — percentage of the chemical removed from
wastewater during treatment before discharge to a body of water. This is a chemical-specific
property entered on the PChem/Fate Inputs screen (See Section 2.0).
Release Days — number of days per year that the chemical is discharged, as entered on the
General Release Information page.
Concentration of Concern (COC) — threshold concentration, in micrograms per liter ((.ig/L).
below which adverse effects on aquatic life are expected to be minimal. PDM in E-FAST V2.0
predicts how many days per year the concentration of the chemical in the receiving stream will
exceed the COC. (Only the first COC value entered on the General Release Information page
appears on the upper half of the page. Up to three of the COC values entered will appear on the
lower half of the page.)
Pretreatment Release — rate of release of the chemical by the facility to a wastewater treatment
facility (kg/site/day), as entered on the General Release Information page.
Post-treatment Release — rate of release of the chemical after treatment by a wastewater
treatment facility (kg/site/day). The post-treatment release amount is equal to the pretreatment
release reduced by the wastewater treatment removal percentage.
Mean Stream Flow — arithmetic mean flow of the ambient water body receiving the facility's
discharge (MLD), extracted from the E-FAST V2.0 database when searching for a facility during
the data entry procedure (See Section 3.1.1.1).
Low Stream Flow — 7Q10 stream flow (i.e., 7 consecutive days of lowest flow over a 10-year
period) (MLD), extracted from the E-FAST V2.0 database when searching for a facility during
the data entry procedure (See Section 3.1.1.1).
• Effluent Flow — Effluent flow of the discharging facility (MLD), extracted from the E-FAST
V2.0 database when searching for a facility during the data entry procedure (See Section 3.1.1.1).
If the facility selected discharges to an ambient water body with a USGS gaging station, E-FAST 2.0 will
not provide an effluent flow. However, the following additional information is provided:
• Gaging Station — identification number for the USGS streamflow monitoring site for the
ambient water body receiving the facility's discharge. PDM accesses daily flow values collected
between 1966 and 1991 to calculate the frequency of exceedence.
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Period of Record — period for which daily streamflow data are available for the selected gaging
station.
Number of Observations — number of times the daily stream flow was measured during the
period of record.
The lower half of the page presents the PDM site-specific estimates. These results are: the
estimated number of days that the COC will be exceeded in the ambient water body that receives
discharge from the facility; as well as the percent of the year that the COC will be exceeded. These are
described below:
Number of Days COC Exceeded — estimate of the number of days/year that the COC is
exceeded.
Percent of Year COC Exceeded — the percentage of year that the COC is exceeded. This is
calculated by dividing the exceedence days/year by 365 and multiplying the result by 100.
In addition to these fields, the PDM Site Results page displays a "Print Page" button that may be used to
generate a hard copy of the data on the screen.
3.1.10 PDM SIC Code Results Page
To develop exposure estimates of surface water releases for which you entered an SIC code to
characterize a facility on the General Release Information page (Figure 3-2a), E-FAST V2.0 performs an
average or high-end analysis for the receiving streams of facilities in the particular industrial category to
predict the exceedences of the COC. The Chemical ID/Release Number box on the left hand side of the
page can be scrolled to show all the stored SIC Code PDM results for all surface water releases analyzed
using the SIC Code surface water release scenario. An example of the PDM SIC Code Results page is
shown in Figure 3-25.
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Screening Level Results
Environmental Releases ] Rivers | SIC Code ] Lakes ] Inhalation | Landfill ] PDM Site PDM SIC Code |
PDM SIC Code Results

7 Help |
Chem D/Re #
Release Activity:
SIC Code Description:
SIC Codes:
WWT Removal:
Release Days:
Concentration of Concern:
Processing
Paint Formulation

25.00 % Pretreatment Release: |
100 dayS/year Post-treatment Release: |
100.00 ug/L
(* High-end scenario
C Average case scenario
1G.00 kg/site/day
12.00 kg/site/day
PDM SIC Code Estimates
Print Page
COC (ug/L)
It Days exceeded
X Year exceedec
[
Run #1
Run #2
Run #3
100.00 |
10.00 |
1.00
44 |
92 [
100
12.08 ]
25.20 |
27.38
Figure 3-25. PDM SIC Code Results Page
The model is based on the mathematical derivation presented by Di Toro (1984). A simple mass
balance approach forms the basis of the model; however, the input variables are not single point
estimates. In reality, these variables are not constant; streams follow a highly variable seasonal flow
pattern and numerous variables in a manufacturing process can affect the chemical concentration and flow
rate of the effluent. PDM uses probability distributions as inputs and calculates the resulting probability
distribution of the concentration in the stream. See Appendix C for a description of the statistical
framework of PDM.
To run PDM, select "Include PDM run"' on the General Release Information page (Figure 3-2a),
and select "Average PDM Analysis (SIC Code)" or "High-end PDM Analysis (SIC Code)" under "Select
PDM Analysis." Using information entered in the PChem/Fate Inputs screen (Figure 2-1) and on the
General Release Information page, PDM estimates the number of days per year and the percentage of the
year the COC was exceeded. The following are short descriptions of the fields that appear on the PDM
SIC Code Results page:
• Release Activity — can be manufacturing, processing, industrial use, or other. This was entered
m a text field on the left-hand side of the General Release Information page (Figure 3-2).
SIC Code Description — text description of the industry selected in the Select an SIC code page.
SIC Codes — the 4-digit code or codes assigned to the industry selected.
• Wastewater Treatment (WWT) Removal — percentage of the chemical removed from
wastewater during treatment before discharge to a body of water. This is a chemical-specific
property entered on the PChem/Fate Inputs screen (See Section 2.0).
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Release Days — number of days per year that the chemical is discharged, as entered on the
General Release Information page.
Concentration of Concern (COC) — threshold concentration, in micrograms per liter ((.ig/L).
below which adverse effects on aquatic life are expected to be minimal. PDM in E-FAST V2.0
predicts how many days per year the concentration of the chemical in the receiving stream will
exceed the COC. (Only the first COC value entered on the General Release Information page
appears on the upper half of the page. Up to three of the COC values entered will appear on the
lower half of the page.)
Pretreatment Release — rate of release of the chemical by the facility to a wastewater treatment
facility (kg/site/day), as entered on the General Release Information page.
Post-treatment Release — rate of release of the chemical after treatment by a wastewater
treatment facility (kg/site/day). The post-treatment release amount is equal to the pretreatment
release reduced by the wastewater treatment removal percentage.
In addition, the results page identifies the type of scenario that was selected in the General
Release Information page. The scenario will be identified as either a high-end or an average case
scenario, as defined below.
High-end Scenario — averaged probability of exceedence of the 10 percent of the facilities of
the selected industrial category that have the highest probability of exceedence for the COC and
the loading rate specified by you for worst-case scenarios.
Average Case Scenario — mean exceedence probability for all facilities within an industrial
category.
The lower half of the page presents the PDM SIC Code estimates. These results are: the
estimated number of days that the COC will be exceeded in the ambient water body that receives
discharge from the facility; as well as the percent of the year that the COC will be exceeded. These are
described below:
Number of Days COC Exceeded — estimate of the number of days/year that the COC is
exceeded.
Percent of Year COC Exceeded — percentage of year that the COC is exceeded. This is
calculated by dividing the exceedence days/year by 365 and multiplying the result by 100.
In addition to these fields, the PDM Site Results page displays a "Print Page" button that may be used to
generate a hard copy of the data on the screen.
3-56
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3.2
Down-the-Drain
OPPT developed the Down-the-Drain module as a screening-level model for estimating
concentrations of chemicals in surface waters that may result from the disposal of consumer products into
household wastewater. The methodology assumes that household wastewater undergoes treatment at a
local wastewater treatment facility and the treated effluent is subsequently discharged into surface waters.
Down-the-Drain also provides estimates of aquatic exposure and human exposure from ingestion of
drinking water and fish that may become contaminated by these household wastewater releases. In
addition, you may select PDM (modified, See Section 3.2.2.2) which allows you to estimate the number
of days per year that the concentration of a chemical in surface water exceeds the concentration of
concern (COC) for aquatic life. Down-the-Drain currently uses data from various EPA water-related
information systems.
Chemical constituents of some household products, such as detergents, are expected to end up in
household wastewater, whereas others, such as fragrance in an air freshener, are not. Before proceeding
with the methods presented below, you should evaluate the physical-chemical properties and the
functional role of the chemical in a product, because these properties could preclude the presence of the
chemical in household wastewater.
3.2.1 Consumer Disposal Inputs Page
In the Consumer Disposal Inputs page, enter a production volume (kg/year) and the exposure
duration (years of use) as shown in Figure 3-26. Down-the-Drain inputs also include the Chemical ID for
the chemical of interest, the bioconcentration factor (BCF), and wastewater treatment removal percentage
previously entered in the Physical-Chemical Properties and Fate (PChem/Fate) Inputs screen (Figure 2-1).
You have the option of running PDM when executing the Down-the-Drain module. If you select "Run
PDM" under the PDM Option, you must enter at least one COC and whether you want it to run a high-
end or average scenario. As was the case for water releases under the General Population and Ecological
Exposure from Industrial Releases module, you may enter up to three COC values to be assessed.
PDM in E-FAST V2.0 predicts the number of days per year the concentration of the chemical in
the receiving stream will exceed the COC. To execute the Down-the-Drain module and display the
Disposal Results page, click on "Run the Disposal Model." The results also will be written to the output
directory.
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IT Disposal Model

Disposal Inputs |
Consumer Disposal Inputs
? Help
r
¦
Chemical ID:
|1123502
Production Volume: | 45000 kg/year
Exposure Duration: | 5? years
PDM Option
C Do NOT run PDM (SIC Code Analysis)
f iRun PDM (SIC Code Analysis)
(• High-end scenario
C Average case scenario
Concentration of Concern:
Run #1 [ 100.00 ug/L
V
J
H Run the Disposal Model
Figure 3-26. Consumer Disposal Inputs Page - Selecting PDM
The following are short descriptions of the fields in the Consumer Disposal Inputs page:
• Production Volume — mass of a chemical produced annually in the USA or an estimate of the
mass that is discharged annually in the USA to wastewater by consumers.
Exposure Duration — number of years that a product would be used by a person; E-FAST V2.0
uses a default value of 57 years (See Table 3-2).
Concentration of Concern (COC) — threshold concentration, in micrograms per liter (• g/L),
below which adverse effects on aquatic life are expected to be minimal.
3.2.2 Disposal Results Page
An example Disposal Results page (Figure 3-27) shows both the inputs to and the results of the
Down-the-Drain module calculations. The following are short descriptions of the fields listed in the
upper half of the page:
Production Volume — mass of chemical produced annually in the USA or an estimate of the
mass that is discharged annually in the USA to wastewater by consumers.
Wastewater T reat merit (WWT) Removal — percentage of the chemical removed from
wastewater during treatment before discharge to a body of water. This is a chemical-specific
property entered on the PChem/Fate Inputs screen (See Section 2.0).
Release days — number of days per year that the chemical is discharged; assumed to be 365
days/year.
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Bioconcentration Factor — indicates the tendency of the chemical to accumulate in living
organisms. This is a chemical-specific property entered on the PChem/Fate Inputs screen (See
Section 2.0).
Exposed Population — can be adults, youths 13 to 19 years, children 6 to 12 years, children 3 to
5 years, infants 1 to 2 years, or infants less than one year old. This was entered on the Screening
Level Main page (Figure 3-1).
Pretreatment Release — the daily per capita release of the chemical before effluent has been
treated by a wastewater treatment facility.
Post-treatment Release — the daily per capita release of the chemical after effluent has been
treated by a wastewater treatment facility. The post-treatment release amount reflects the
wastewater treatment removal percentage you supplied in Figure 2-1. the Physical-Chemical
Properties and Fate component.
In addition to these fields, the top portion of the Disposal Results page displays a "Print Page" button that
may be used to generate a hard copy of the data on the screen. The hard copy includes the data in all of
the tabs in the lower portion of the screen (PDM Information, Drinking Water In formation, Fish Ingestion
Information, and Concentrations), so there is no need to click the "Print Page" button for each of these
tabs.
0 Disposal Model
JflJi
Disposal Inputs Disposal Results |
Disposal Results
7 Help I
Production Volume: |
WWT Removal: [~~
4.50E+04 kg/year
Exposed Population: |Adult
25.00 %
Release days: |
Bioconcentration Factor:
365.00 days
Pretreatment release: |
Post-treatment release: \~
30.00 L/kg
PDM Information ] Drinking Water Information | Fish Ingestion Information Concentrations j
r
Aquatic Exposuie Estimates - Suilace Water
4.24E-04 g/person/day
3.18E-04 g/person/day
t Page j
Descriptor
| Harmonic Mean I
30q5 I
7q10 |
1q10
50 Percentile
j Stream Dilution Factor
134.85 |
39.66 |
24.22 |
20.08
| Concentration (ug/L)
6.08E-03 |
2.07E-02 |
3.38E-02 |
4.08E-02
10 Percentile
I Stream Dilution Factor
7.95 |
1.80 |
1.00 |
1.00
| Concentration (ug/L)
0.10 |
0.46 |
0.82 |
0.82
Figure 3-27. Disposal Results Page - Aquatic Exposure Estimates - Surface
Water
The four tabs located in the lower half of the page allow you to view Concentrations, PDM
Information, Drinking Water Information, and Fish Ingestion Information.
3-59
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3.2.2.1 Disposal Results Page - Concentrations
Based on a specified annual production volume (mass of chemical produced annually or
discharged annually to wastewater by consumers) and the U.S. population, Down-the-Drain estimates the
total daily per capita release of a chemical in household wastewater. The household daily release and
stream dilution factors, along with the specified wastewater treatment efficiency, are then used to
calculate a screening-level estimate of the time-averaged surface water concentration (high-end and
median) of a chemical substance released by a wastewater treatment facility receiving household
wastewater (assuming all wastewater entering a treatment facility is from residential sources). Surface
water concentrations are estimated under four receiving stream flow conditions (1Q10 low flow, 7Q10
low flow, 30Q5 low flow, and harmonic mean flow) as described in Section 3.1.4.1, using the stream
dilution factors for all wastewater treatment facilities based on 10th and 50th percentile values.
Estimation of Household Wastewater Releases
E-FAST V2.0 uses the following equation to estimate the total daily per capita release of a
chemical in household wastewater:
where:
Hr =
PV
Pop =
CF1 =
H 4 PV_ x 1000 grams x ^
R Pop 1 kg
(Eq. 3-20)
Daily per capita release of the chemical to a wastewater treatment facility
(g/person/day)
Production volume (kg/year)
2003 U.S. resident population (2.908 x 10s persons) (U.S. Bureau of the Census,
2004-2005)
Conversion factor (year/365 days)
Estimation of Surface Water Concentrations
The following equations are used to calculate a screening-level estimate of the time-averaged
surface water concentration of a chemical released by a wastewater treatment facility receiving household
wastewater:
Hu
SWC 4
median H
1
Qh
1 )
WWT
100
SDF.
median
CFl
(Eq. 3-21)
Hu
SWChlgh 4
1
Qh
1 )
WWT
100
SDF,
low
CFl
(Eq. 3-22)
where:
SWC,
swc
H„
median
high
Median time-averaged surface water concentration ((.ig/L)
High-end time-averaged surface water concentration (j^ig/L)
Daily per capita release of chemical (i.e., pretreatment release)
(g/person/day)
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SDFmedmn = 50th percentile stream dilution factor for streams to which wastewater
treatment facilities discharge
SDFlow = 10th percentile stream dilution factor for streams to which wastewater
treatment facilities discharge
CF1 = Conversion factor (106 • g/g)
The above factors, and the assumptions on which they are based, are discussed below. The
underlying conservative assumption used in these equations is that all wastewater entering a wastewater
treatment facility is from residential sources. With this assumption, readily available data can be used to
estimate concentrations of the chemical in ambient receiving waters.
Daily Household Release of Chemical (Hk) — pretreatment release; See Equation 3-20.
Household Wastewater Volume Released Daily (Qjj) — based on the subset of POTWs that
have an accessible domestic flow value and resident-population-served; derived from an EPA
database of POTWs (See Appendix B). The household wastewater flow of 388 L/person/day was
the 50th percentile value. This value is used as the daily per capita wastewater volume released
in Down-the-Drain.
Wastewater Treatment (WWT) Removal — estimate of chemical removal efficiency,
dependent on the physical-chemical properties of the chemical of concern and the extent of
wastewater treatment (e.g., primary, secondary). Most chemicals in household wastewater can be
expected to be removed to some extent during wastewater treatment.
Stream Dilution Factor (SDFmedian, SDFlow) — equal to the volume of the receiving stream flow
under four flow conditions divided by the volume of the wastewater treatment facility effluent
flow. These values were obtained from the Stream Dilution Factor Program (SDFP) for 36
industrial categories. (SDFP is a software program originally developed by the OW to obtain
effluent and stream flow frequency distributions for a given industrial category (SIC code).
Revised by OPPT, the major purpose of SDFP is to (1) retrieve receiving stream flow data for
facilities in a particular SIC code (direct dischargers), (2) calculate dilution factors for each
facility (receiving stream flow divided by effluent flow), and (3) rank the flow data and dilution
factors and report the results in terms of percentiles. See Appendix B for more details. Harmonic
mean, 30Q5, and 1Q10 flows are calculated from the 7Q10 flows and arithmetic mean flows.
3.2.2.2 Disposal Results Page - PDMInformation
If the module is run with PDM, it predicts the number of days of exceedence of each of the user-
specified surface water COC values (See Figure 3-28). The following is a short description of each field
in the lower half of the page:
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Concentration of Concern (COC) - threshold concentration, in micrograms per liter ((ig/L),
below which adverse effects on aquatic life are expected to be minimal.
Number of Days COC Exceeded — estimate of the number of days/year that the COC is
exceeded.
Percent of Year COC Exceeded — percentage of year that the COC is exceeded. This is
calculated by dividing the exceedence days/year by 365 and multiplying the result by 100
(releases are assumed to occur 365 days per year).
High-end Scenario — averaged probability of exceedence of the 10 percent of the facilities of
the selected industrial category that have the highest probability of exceedence for the COC and
the loading rate specified by you for the worst-case scenarios.
Average Case Scenario — mean exceedence probability for all facilities within an industrial
category.
17 Disposal Model
Disposal Inputs Disposal Results |
Disposal Results
•7 Help |
Production Volume: |
WWT Removal: T
Release days: [
Bioconcentration Factor:
4.50E+04 kg/year
Exposed Population: |Adult
25.00 %
365.00 days
Pretreatment release: |~~
Post-treatment release:
4.24E-04 g/person/day
3.18E-04 g/person/day
30.00 L/kg
PDM Information | Drinking Water Information ] Fish Ingestion Information ] Concentrations ]
t Page |
PDM Disposal Exposure Estimates
Concentration of concern (ug/L):
Number of days concentration of concern exceeded (days):
X of year concentration of concern exceeded [%):
100.00 p
10.00 |
1 00
5.56E 04 [
0.36 |
35.07
1.52E-04 |
9.73E-02 |
9.61
(* High-end scenario
C Average case scenario
Figure 3-28. Disposal Results Page - PDM Disposal Exposure Estimates
Estimating Probability of Exceeding Concentrations of Concern
Down-the-Drain incorporates a modified version of PDM to calculate the number of days of
exceedence of a surface water COC. This version is limited to the following:
Addresses only POTWs;
Uses data from an EPA survey of POTWs;
Uses a typical per capita release (instead of discharge loading) to generate POTW loading
3-62
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by multiplying estimates of population served by the estimates of per capita household releases.
The Probabilistic Dilution Model is based on the mathematical derivation presented by Di Toro
(1984). A simple mass balance approach forms the basis of the model; however, the input variables are
not single point estimates. In reality, these variables are not constant; streams follow a highly variable
seasonal flow pattern and numerous variables in a manufacturing process can affect the chemical
concentration and flow rate of the effluent. PDM uses probability distributions as inputs and calculates
the resulting probability distribution of the concentration in the stream. See Appendix C for a description
of the statistical framework of PDM.
3.2.2.3 Disposal Results Page - Drinking Water Information
The Drinking Water Information tab (Figure 3-29) presents the acute and chronic exposure doses
for individuals who ingest drinking water from streams and rivers that receive wastewater discharges
containing the chemical of concern. The first column, "Exposure Type," lists three different
measurements of exposure. To the right of each, under the "Results" heading, are the corresponding 50th
and 10th percentile exposure values. The subsequent columns contain the exposure factors for the age
group selected (See Table 3.2 in Section 3.1.2). The following are short descriptions of the fields in the
lower half of this page:
• 50th Percentile Results — exposure calculations based on the median (i.e., 50th percentile)
surface water concentrations and represent central tendency exposure. These flows are used to
represent mid-sized stream flows.
10th Percentile Results — exposure calculations based on the high-end (i.e., upper 10th
percentile) surface water concentrations and represent the bounding high-end exposures. These
flows are used to represent small streams.
The exposure types and exposure factors are defined below:
Exposure Types
Potential Lifetime Average Daily Dose (LADDPOX) — from drinking water intake; calculated to
represent chronic exposures to contaminated drinking water over a lifetime. These doses are
generally used for cancer calculations.
• Potential Lifetime Average Daily Concentration (LADCPOT) — of the chemical of concern in
drinking water; calculated to represent chronic lifetime concentration. These concentrations are
generally used for cancer calculations.
Potential Acute Dose Rate (ADRPOX) — from drinking water intake; normalized over a shorter
time period (e.g., 1 day).
3-63
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Exposure Factors
Exposure Duration (ED) — number of years that a product would be used by a person; E-FAST
V2.0 uses a default value of 57 years (See Table 3-2).
Averaging Time (AT) — period of time over which exposures are averaged.
Body Weight (BW) — mean body weight for the population being assessed.
Drinking Water Ingestion Rate (IRdw) — used for calculating acute and chronic exposures.
t£t Disposal Model
Disposal Inputs Disposal Results
Disposal Results
Production Volume: |
WWT Removal: [~
Release days: \
Bioconcentration Factor:
4.50E+04 kg/year
25.00 %
365.00 days
Exposed Population: |Adult
Pretreatment release: |
Post-treatment release: |
30.00 L/kg
PDM Information Drinking Water Information Fish Ingestion Information ] Concentrations ]
Drinking Water Exposure E stimates
7 H..I(I I
4.24E-04 g/person/day
3.18E-04 g/person/day
Print Page |
Exposure Type
| 50%ile Res. |
10%ile Res.
1 ED (yrs)
AT lyrs) |
BW (kg) |
IR (L/day)
Cancer
| LAD D pot (mg/kg/day)
9.01E-08
1.53E-0G
57.00 |
75.00 |
71.80 |
1.40
LADCpoi (mg/L)
4.G2E-0G
7.83E-05
57.00 |
75.00 |
NA |
NA
Acute
| ADRpot (mg/kg/day)
1.73E-06
3.80E-05
NA |
1 day |
71.80 |
GOO
Figure 3-29. Disposal Results Page - Drinking Water Exposure Estimates
Estimation of Drinking Water Potential Doses
The following equations are used to calculate a screening-level estimate of the potential drinking
water dose rate of a chemical release by a wastewater treatment facility receiving household wastewater.
10th percentile surface water concentrations:
SWCU , y IR. * RD x CF1
ADRpot 4 *L (E 3-23)
POT BW m AT ^4- J --'I
SWChi . • IR , x RD x ED x CF1 m
IAD1)4 ^± (Eq. 3-24)
POT BW x AT x CF2
SWC, , x RD M ED x CF1
LADCpm 4 * — (En 3-25)
p°T AT x CF2 Itq. i 2.i)
3-64
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50th percentile surface water concentrations:
ADR 4 SWCmed,an * IR^ * X CF1 (Eq 3_26)
FU1 BW x AT
LADD 4 SWCmedian xIR^xRD* ED* CFl (Eq 3.27)
POT BW x AT x CF2
LADCpot 4
SWC
median
RD x ED x CFl
AT x Ci^2
(Eq. 3-28)
where:
adrpot
LADDpot
LADCpoi
SWChl^
SWCmedian
' Rdw
RD
ED
BW
AT
CFl
CF2
Potential Acute Dose Rate from drinking water intake (mg/kg/day)
Potential Lifetime Average Daily Dose from drinking water intake
(mg/kg/day)
Potential Lifetime Average Daily Concentration (mg/L)
10th percentile time-averaged surface water concentration (j^ig/L)
50th percentile time-averaged surface water concentration (j^ig/L)
Drinking water intake rate (L/day)
Days of release from wastewater treatment facility (1 day for ADRP0T;
365 days/year for LADDP0T and LADCP0T)
Exposure duration (years of product usage)
Body weight (kg)
Averaging time (day for ADRP0T; years for LADDP0T and LADCP0T)
Conversion factor (10 3 mg/|_ig)
Conversion factor (365 days/year)
Descriptions of selected parameters are briefly discussed below:
Time-averaged Surface Water Concentration (SWCmedian, SWChigh) — assumed to be the same
as the drinking water concentration of the chemical as calculated using Equations 3-21 and 3-22
in Section 3.2.2.1. This conservative assumption implies either that water is ingested as raw
stream water or, if treated before ingestion, that drinking water treatment removes none of the
chemical.
Days of Release from a Wastewater Treatment Facility (RD) — reflects the frequency of
drinking contaminated water and is a constant. It is set at 1 day for acute scenarios and 365 days
per year for chronic scenarios.
Exposure Duration (ED) — reflects the number of years a product would be used by a person;
E-FAST V2.0 uses a default value of 57 years (see Table 3-2). This parameter is not applicable
for children's exposure because LADDpot and LADCpot are not calculated for children.
3-65
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3.2.2.4 Disposal Results Page - Fish Ingestion Information
The Fish Ingestion Information tab of the Disposal Results page presents the predicted acute and
chronic exposure doses for consumers who ingest fish from streams and rivers that receive wastewater
discharges containing the chemical of concern. The exposure doses are calculated using the estimated
median and high-end surface water concentrations in a water body receiving discharges from a POTW
treating household wastewater (Figure 3-30).
17 Disposal Model
Disposal Inputs Disposal Results I
^JnJxJ
Disposal Results
? Help I
Production Volume
WWT Removal
Release days
Bioconcentration Factor
4.50E+04 kg/year
25.00 %
365.00 days
30.00 L/kg
Exposed Population: |Adult
Pretreatment release: [
Post-treatment release: |
4.24E-04 g/person/day
3.16E-04 g/person/day
PDM Information | Drinking Water Information Fish Ingestion Information j Concentrations ]
Print
Page j
Fish Ingestion Exposure Estimates
| Exposure Type
1 50%ile Res. 1
10%ile Res.
1 ED [yrs] |
AT lyrs)
BW (kg] |
IR (g/day)
Cancer
| LAD D pot (mg/kg/day]
1.16E 08
1.96E 07
57.00 |
75.00 |
71.80 |
6.00
| LADCpot (mg/kg)
1.39E-04
2.35E-03
57.00 |
75.00 |
NA |
NA
Acute
| ADR pot (mg/kg/day)
1.11E 06
2.45E 05
NA |
1 day |
71.80 |
129.00
Figure 3-30. Disposal Results Page - Fish Ingestion Exposure Estimates
The following are short descriptions of the fields in the lower half of the page:
10th Percentile Results — exposure calculations based on the high-end (i.e., upper 10th
percentile) surface water concentrations (SWChlgh) and represent the bounding high-end
exposures. These flows are used to represent small streams.
• 50th Percentile Results — exposure calculations based on the median (i.e., 50th percentile)
surface water concentrations (SWCmedian) and represent central tendency exposure. These flows
are used to represent mid-sized stream flows.
Exposure Types
Potential Lifetime Average Daily Dose (LADDPOX) — from ingestion of fish tissue; calculated
to represent chronic exposures to fish over a lifetime. These doses are generally used for cancer
calculations.
Potential Lifetime Average Daily Concentration (LADCPOT) — of the chemical of concern in
ingested fish tissue; calculated to represent chronic lifetime concentration. These concentrations
are generally used for cancer calculations.
3-66
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Potential Acute Dose Rate (ADRPOT) — from ingestion of fish tissue; normalized over a shorter
time period (e.g., 1 day).
Exposure Factors
• Exposure Duration (ED) —number of years that a product would be used by a person; E-FAST
V2.0 uses a default value of 57 years (See Table 3-2).
Averaging Time (AT) — period of time over which exposures are averaged.
Body Weight (BW) — mean body weight for the population being assessed.
Fish Ingestion Rate (IRfish) — used for calculating acute and chronic exposures.
Estimation of Potential Doses via Fish Ingestion
The following equations are used to calculate a screening-level estimate of the potential dose rate
from ingestion of fish that may become contaminated with a chemical discharged by a wastewater
treatment facility that receives household wastewater.
10th percentile surface water concentrations:
ADRpot 4
SWCh,gh x IRfish x RD x BCF x CF1 x CF3 (Eq. 3-29)
BW x AT
LADDunr 4
SWCh,gh x IRfish x BCF x RD X ED x CF1 x CF3 (Eq. 3-30)
POT BW x AT x CF2
LADCpot 4
SWCh,gh x RD x ED x BCF x CF1 (Eq. 3-31)
AT x CF2
50th percentile surface water concentrations:
ADRpot 4
SWCmedmn X IRm x 111) x BCF' x CF1 x CF3 (Eq. 3-32)
BW x AT
LADDun^, 4
SWCmedian X IRfish x BCF x RQ X /,;/) X CF1 x CF3 (Eq. 3-33)
POT BW x AT x CF2
SWC , x RD x ED x BCF x Ci^7 (Eq. 3-34)
LADCpot 4 V 4 7
AT x CF2
3-67
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Potential Acute Dose Rate from fish ingestion (mg/kg/day)
Potential Lifetime Average Daily Dose from fish ingestion (mg/kg/day)
Potential Lifetime Average Daily Concentration in fish (mg/kg)
10th percentile time-averaged surface water concentration (j^ig/L)
50th percentile time-averaged surface water concentration (|_ig/L)
Fish ingestion rate (g/day)
Estimate of chemical's bioconcentration potential (L/kg)
Days of release from a wastewater treatment facility (1 day for ADRP0T;
365 days/year for LADDP0T and LADCP0T)-
number of years that a product would be used by a person; E-FAST V2.0
uses a default value of 57 years (see Table 3-2).
Body weight (kg)
Averaging time (day for ADRP0T; years for LADDP0T and LADCP0T)-
Conversion factor (10 3 mg/(.ig)
Conversion factor (365 days/year)
Conversion factor (10 3 kg/g)
3-68
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3.3 Consumer Exposure Module (CEM)
The Consumer Exposure Module (CEM) is an interactive model within E-FAST V2.0 that
calculates conservative estimates of potential inhalation exposure, and potential and absorbed dermal
exposure to chemicals in certain types of consumer products. CEM allows for screening-level estimates
of Potential Acute Dose Rates (ADRP0T), Potential Peak Concentrations (CPP0T), and Potential Lifetime
Average Daily Concentrations (LADCP0T) and Dose Rates (LADDP0T). Because the model incorporates
either a combination of upper percentile and mean input values or all upper percentile input values for
various exposure factors in the calculation of potential exposures/doses, the exposure/dose estimates are
considered "high-end" to "bounding" estimates.
CEM uses six data entry pages to collect the information necessary to calculate inhalation and
dermal exposure. These pages are titled "Introduction," "Scenario," "Inhalation Input," "Day of Use,"
"Days After Use," and "Dermal Input." Additional data inputs necessary to run CEM (weight fraction of
the chemical in the consumer product (central tendency and high-end (e.g., median and 90th percentile,
respectively), molecular weight of the chemical (g/mol), and vapor pressure of the chemical) are
previously entered in the Physical-Chemical Properties and Fate (PChem/Fate) Inputs screen (Figure 2-1).
3.3.1 Introduction Page
The opening page for CEM is shown in Figure 3-31. The introductory text describes the
conservative nature of the CEM exposure results. Exposure Factors Handbook (U.S. EPA, 1997) was the
main source from which many of the default values for the scenarios have been taken. The page prompts
you for three pieces of information: an identification number (Chemical ID), a product name, and model
run comments. These are optional and are not required for you to continue. The page also provides a
"Quick Assist" button which provides help information. From the Introduction page you should then
select the Scenario tab to go to the Scenario Data page which must be completed before you can continue
to the other input screens.
3-69
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1 RSI Consumer Exposure Module (CEM]
wm. Inixl
File Run Model Help

Introduction

Introduction Scenario | Inhalation Input Day of Use | Days After Use Dermal Input

Consumer Exposure Module (CEM)

CEM is an interactive model which calculates conservative estimates of potential inhalation and dermal exposure
to consumer products. Because the model incorporates upper percentile and mean input values for various
exposure factors in the calculation of potential exposures / doses, the exposure / dose estimates are considered
to be1 high end1 to' bounding' estimates (Guidelines for Exposure Assessment, USEPA, 1992). The dermal
portion of CEM uses a film- thickness approach, which assumes that exposure occurs from a thin layer of the
consumer product on a defined surface area, to determine potential exposure. Few data exist on the actual
thickness of films of various products on human skin. Therefore, due to the uncertainty associated with the
amount of product forming a film on the skin, the dermal exposure estimates are considered less certain than
those calculated in the inhalation portion of CEM.

Default exposure factor values have been extracted from U.S. EPA's Exposure Factors Handbook (August
1997). This handbook can be obtained from the Agency by calling (513) 569-75G2, or can be obtained at the
http:Avww.epa.gov/ORD/WebPubs/exposure web site.

Identification Number: ] 1123502 Product: |versatone

Model Run Comments (this entry allows the user to enter any free flowing textual description about
the model run.)

Sample Run Number 1

Quick Assist]

I
Figure 3-31. CEM Introduction Page
3.3.2 Scenario Page
The Scenario page (Figure 3-32) is divided into five general exposure categories, each with
corresponding generic consumer product scenarios. The exposure categories with their corresponding
consumer product scenarios are listed below. You also have the option to select the User-Defined
scenario. To use this scenario, you must provide specific exposure factors (most defaults are not
provided). More information on the User-Defined scenario is provided in Section 3.3.2.2.
3-70
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Qj Consumer Exposure Module (GEM)
File Run Model Help
Scenario Data
Introduction Scenario Inhalation Input I Day of Use Days After Use Dermal Input
Product Applied to Surface (Dermal Inhalation)
C General Purpose Cleaner
(• Late:-: Paint
Product Sprayed on Surface (Inhalation)
C Fabric Protector
C Aerosol Paint
Product Added to Water (Dermal, Inhalation)
C Laundry Detergent
Product Placed in Environment (Inhalation)
C Solid Air Freshener
Product Directly Contacting Skin (Dermal)
P Bar Soap
r Used Motor Oil
C User Defined Scenario
Age Group
[Adult
Quick Assist
Edit Weight Fractions for Selected Scenario
Figure 3-32. Scenario Page
The scenario selection portion of the screen allows you to choose the type of consumer product
you are modeling. The model is based on the assumption that all exposure scenarios take place inside the
home or car. The generic consumer product scenario (Section 3.3.2.1) assumes that the exposed
population consists of individuals who stay at home, such as homemakers. The user-defined consumer
product scenario (Section 3.3.2.2) requires the user to specify where the exposed individual spends each
hour of his or her day.
The house used in CEM is considered to be a two-zone house. Zone 1 is the room where the
consumer product is used and Zone 2 is the remainder of the house. The house contains a bedroom, a
kitchen, a bathroom, a living room, and a utility room. The "Room of Use," where the product is used,
depends on the scenario selected. For instance, the default room of use for the General Purpose Cleaner
scenario is the kitchen and the default room of use for the Laundry Detergent scenario is the utility room.
The magnitude of Zone 1 also changes with the room of use. For example, the volume of the kitchen is
larger than the volume of the bathroom. The user may also specify a third zone of activity ("Out"), where
no exposure to the consumer product occurs.
3.3.2.1 Generic Consumer Product Scenarios
General Purpose Cleaner - Dermal and Inhalation Scenario. Exposure occurs during
cleaning of the outside of appliances and countertops. The model derived the number of events per
lifetime and the years per use from the upper-end values of cleaning events from the Household Cleaning
Products Survey (Westat, 1987a), then extrapolated this figure to a lifetime value using professional
judgment. The model assumes six uses per week for 50 weeks per year (assumes one 2-week vacation per
year) for 57 years (product users between the ages of 18 and 75). The duration of use and the mass of the
product used were denved from the Source Ranking Database (Versar, 2003). The surface area to body
weight ratio (SA/BW) of 15.6 cnr/kg is based on both hands of an adult being exposed to the cleaning
3-71
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solution (See Section 3.3.6). The film thickness of 2.10E-03 cm was derived from the initial film
thickness of water uptake on the hands from handling a rag (U.S. EPA, 1987c). The dilution fraction of
0.016 and density of 1.04 g/cm3 were estimated from the dilution of % cup of cleaner per gallon of water
(Versar, 1986).
Interior Latex Paint - Dermal and Inhalation Scenario. Exposure occurs during painting of
the rooms of a house. The value of four events per year was taken from the Household Solvent Products
Survey (Westat, 1987b). Professional judgment assumed that these painting events would occur 1 out of
every 5 years, producing a years-of-use value of 11, occurring over the course of 57 years (product users
between the ages of 18 and 75). Default values for mass of product used and duration of use also were
derived from the Household Solvent Products Survey (Westat, 1987b). The adult SA/BW of 4.5 cm2/kg
was based on exposure of 10 percent of the face, hands, and forearms (See Section 3.3.6). The film
thickness of 9.81E-03 cm was derived from the estimated film thickness of a bath oil and water mixture
on the hands after immersion. The dilution fraction was assumed to be full strength (1.00); the density
equals 1.16 g/cm3. (U.S. EPA, 1987c; Versar, 1986).
Fabric Protector - Inhalation Scenario. Exposure occurs from using a fabric protector on
clothes and furniture in a house. The frequency of use was assumed to be three times per year for 57
years (occurring between the ages of 18 and 75) and was derived from the Household Cleaning Products
Survey (Westat, 1987a).
Aerosol Paint - Inhalation Scenario. Exposure occurs during spraying of aerosol paint indoors
for small paint jobs. The value of six events per year was taken from the Household Solvent Products
Survey (Westat, 1987b). Professional judgment assumed that these painting events occur 1 out of every 5
years, producing a years-of-use value of 11, occurring over a period of 57 years (product users between
the ages of 18 and 75). Default values for mass of product used and duration of use also were derived
from the Household Solvent Products Survey (Westat, 1987b).
Liquid Laundry Detergent - Inhalation Scenario. Exposure occurs when machine washing
laundry at home. The number of events per lifetime and the years of use were derived from the Cleaning
Products Survey (Westat, 1987a). The duration of use and the mass of the product used were derived
from the Source Ranking Database (Versar, 2003). The frequency of use was assumed to be 312 events
per year over a period of 57 years (product users between the ages of 18 and 75).
Liquid Laundry Detergent - Dermal Scenario. Exposure occurs when hand washing delicate
clothing. The frequency of use was assumed to be once per week for 57 years (occurring between the ages
of 18 and 75) and was derived from the Household Cleaning Products Survey (Westat, 1987a). The adult
SA/BW of 15.6 cm2/kg is based on exposure of both hands (See Section 3.3.6). The film thickness of
4.99E-03 cm was derived from the initial film thickness of water on the hands after initial immersion.
The dilution fraction of 0.002 and density of 1.113 g/cm3 were estimated from the dilution of 'A cup of
detergent per medium load (U.S. EPA, 1987c; Versar, 1986). The frequency of use was assumed to be
312 events per year over a period of 57 years (product users between the ages of 18 and 75).
Solid Air Freshener - Inhalation Scenario. Exposure occurs from the use of a solid air
freshener in the home. The number of events per year was based on the assumption that an air freshener
is replaced every 60 days during the course of a year for 57 years (adult scenario). Product users are
passively exposed to the air freshener. The mass of product used was derived from the Source Ranking
Database (Versar, 2003). The duration of use assumed that an individual is exposed to a solid air
freshener for a minimum of 24 hours a day for 30 days and a maximum of 24 hours a day for 90 days
before replacing the air freshener.
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Bar Soap - Dermal Scenario. Exposure occurs while washing the whole body and hands during
showering, bathing, and washing the hands. The number of events assumed five showers or baths a week
for individuals between the ages of 1 and 16 and 65 and 75 (6,500 times/lifetime), one shower per day
between the ages of 16 and 65 (17,836 times/lifetime), and two hand washes per day between the ages of
1 and 75 (54,020 times/lifetime). These usage rates produce a frequency of use of 329 events per year for
the body and a frequency of use of 730 events per year for the hands for 74 years (for the lifetime
exposure estimate). The SA/BW ratios of 286 and 15.6 are based on exposure of the body and the hands,
respectively. Table 3-3 presents the SW/BW ratios for all of the exposure age groups in E-FAST V2.0.
The film thickness of 9.81E-03 cm was derived from the film thickness of bath oil and water mixture on
the hands after immersion (U.S. EPA, 1987c). The dilution fraction of 0.001 and density of 0.94 g/cm3
were estimated from the monthly consumption of soap and the amount of water needed to form lather
(U.S. EPA, 1985a).
Used Motor Oil - Dermal Scenario. Exposure occurs while changing the oil in a car. The
number of events was derived from the recommended length of time between oil changes (3 months), or
four times a year for 57 years (performed between the ages of 18 and 75). The adult SA/BW of 7.8
cm2/kg was derived from exposure of the insides (palms and fingers) of both hands (See Section 3.3.6).
The film thickness of 1.19E-02 cm was derived from the uptake of mineral oil on the hands after
immersion. (U.S. EPA, 1992c) The dilution fraction was assumed to be full strength (1.00); the density
equals 0.88 g/cm3. (Versar, 1986).
3-73
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Table 3-3. Default Surface Area/Body Weight (SA/BW) Ratios Used in CEM Module for Bar Soap
K\|)osiiiv
PiinuiK-liT
Popiihilion
l'l\|)()SUIV
l\|)C
Ddiiull
Yiiluc
Source
( OIllllKMll
Total Body
SA/BW ratio
Adult
All
286 cm2/kg
U.S. EPA
(1997)
Median adult SA/BW ratios (EFH Table 6-9). Based on an analysis of direct
matched measurements of surface area and body weight for adults.

Youth
(age 13-19)
Acute
269 cm2/kg
U.S. EPA
(1997)
SA/BW ratio was calculated by treating surface area and body weight as independent
variables. SA was calculated by averaging the median SAs for males and females in
the 13 to <18 year age groups (EFH Tables 6-6 and 6-7) and body weight was
calculated by averaging the mean body weights for 13 to 19 year olds (EFH Table 7-
3). SA/BW was calculated as the ratio of the surface area to body weight.

Child
(age 6-12)
Acute
334 cm2/kg
U.S. EPA
(1997)
SA/BW ratio was calculated by treating surface area and body weight as independent
variables. SA was calculated by averaging the median SAs for males and females in
the 6 to <13 year age groups (EFH Tables 6-6 and 6-7) and body weight was
calculated by averaging the mean body weights for 6 to 12 year olds (EFH Table 7-
3). SA/BW was calculated as the ratio of the surface area to body weight.

Small Child
(age 3-5)
Acute
411cm2/kg
U.S. EPA
(1997)
SA/BW ratio was calculated by treating surface area and body weight as independent
variables. SA was calculated by averaging the median SAs for males and females in
the 3 to <6 year age groups (EFH Tables 6-6 and 6-7) and body weight was
calculated by averaging the mean body weights for 3 to 5 year olds (EFH Table 7-3).
SA/BW was calculated as the ratio of the surface area to body weight.

Infants
(age 1-2)
Acute
617 cm2/kg
U.S. EPA
(1997)
Median SA/BW ratio for children age 0-2 years (EFH Table 6-9).

Infants
(age <1)
Acute
617 cm2/kg
U.S. EPA
(1997)
Median SA/BW ratio for children age 0-2 years (EFH Table 6-9).
3-74
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Table 3-3. Default Surface Area/Body Weight (SA/BW) Ratios Used in CEM Module for Bar Soap (Cont'd)
K\|)osiiiv
PiinimcliT
Popuhilion
l'l\|)()SUIV
T \ |R'
Ddiiull
Yiiluc
Source
( OIlllllClll
Hand SA/BW
ratio
Adult
All
15.6 cm2/kg
Unpublished
Based on an analysis of direct matched measurements of surface area and body
weight (Phillips et al., 1993).

Youth
(age 13-19)
Acute
14.3 cm2/kg
U.S. EPA
(1997)
SA/BW ratio for hands was calculated by multiplying the Total Body SA/BW shown
above for this age group by the mean fraction of the total body represented by the
hands for this age group (EFH Table 6-8).

Child
(age 6-12)
Acute
17.1 cm2/kg
U.S. EPA
(1997)
SA/BW ratio for hands was calculated by multiplying the Total Body SA/BW shown
above for this age group by the mean fraction of the total body represented by the
hands for this age group (EFH Table 6-8).

Small Child
(age 3-5)
Acute
24.0 cm2/kg
U.S. EPA
(1997)
SA/BW ratio for hands was calculated by multiplying the Total Body SA/BW shown
above for this age group by the mean fraction of the total body represented by the
hands for this age group (EFH Table 6-8).

Infants
(age 1-2)
Acute
34.0 cm2/kg
U.S. EPA
(1997)
SA/BW ratio for hands was calculated by multiplying the Total Body SA/BW shown
above for this age group by the mean fraction of the total body represented by the
hands for this age group (EFH Table 6-8).

Infants
(age < 1)
Acute
34.0 cm2/kg
U.S. EPA
(1997)
SA/BW ratio for hands was calculated by multiplying the Total Body SA/BW shown
above for this age group by the mean fraction of the total body represented by the
hands for this age group (EFH Table 6-8).
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3.3.2.2 User-Defined Scenario
In the User-Defined scenario, you are responsible for providing all inputs, except those defined
by the characteristics of the exposed individual, e.g., a child age 6-12 cannot be exposed for greater than 7
years, so the exposure duration entry should not exceed that value. Although you cannot specifically
define the equations, you can select the way the emissions are determined by selecting how the product is
used. Depending on the product's use or application, CEM will use one of the following to determine the
inhalation emissions: an incremental source model, a double exponential model, or a constant emission
rate model. For the generic scenarios already programmed in CEM, emissions are varied over time using
equations that account for the manner in which the product is used or applied.
When you select the User-Defined scenario, a secondary pop-up screen (Figure 3-33) will query
you for the general product type being considered, such as a "Product Applied to Surface." You may also
select to calculate potential dermal dose rates or absorbed dermal dose rates for aqueous media.
User Defined Scenario Description
Scenario Category
Product Applied to Surface (Dermal Inhalation - Incremental Source Model)
C Product Applied to Surface [Dermal, Inhalation - Double Exponential Model]
C Product Sprayed on Surface (Inhalation - Constant Rate and Incremental Model)
C Product Added to Water (Dermal.. Inhalation - Constant Rate Model)
r Product Placed in Environment (Inhalation ¦ Constant Rate Model)
C Product Contacts Skin Directly (Dermal)
Potential Dose
C Absorbed Dose for Aqueous Media
Select from'one of the following options:
f~~ Pick permeability coefficient from list
r Enter known permeability coefficient
V Estimate permeability coefficient from known Kow

OK
Figure 3-33. User-Defined Scenario Description Screen
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Product Applied to Surface - Incremental Source Model. For a product applied to a surface,
such as a general purpose cleaner, CEM uses an incremental source model. This model assumes a
constant application rate over the user-specified duration of use; each instantaneously applied segment
has an emission rate that declines exponentially overtime, at a rate that depends on the chemical's
molecular weight and vapor pressure.
Product Applied to Surface - Double Exponential Model. Latex paint is handled much like a
general purpose cleaner, with two exceptions: (1) a double exponential model is used to account for an
initial fast release that is governed primarily by evaporation, followed by a slow release dominated by
diffusion; and (2) only 25 percent of the applied mass is released because a substantial fraction of the
mass becomes trapped in the painted substrate when it dries. Empirical studies reported by Wilkes et al.
(1996) support the assumption of 25 percent mass released and estimate a relationship between the fast
rate of decline (kl) and vapor pressure (VP), and between the slow rate of decline and molecular weight
(MW).
Product Sprayed on Surface - Constant Rate and Incremental Models. For a product
sprayed on a surface, such as a fabric protector or an aerosol paint, a portion (default of 1 percent) is
assumed to be aerosolized and therefore immediately available for uptake by inhalation. The remainder is
assumed to contact the target surface, and to subsequently volatilize at a rate that depends upon the
chemical's molecular weight and vapor pressure. The aerosolized portion is treated using a constant
emission rate model. The remaining (non-aerosolized) mass is treated in the same manner as described
for a general purpose cleaner, combining a constant application rate with an exponentially declining rate
for each instantaneously applied segment.
Product Added to Water - Constant Rate Model. For a product added to water, such as a
laundry detergent, the chemical is assumed to emit at a constant rate over a duration that depends on its
molecular weight and vapor pressure. If this duration is longer than the user-specified duration of use,
then the chemical emissions are truncated at the end of the product-use cycle (i.e., in the case of a
washing machine, the remaining chemical mass is assumed to go down the drain). The potential duration
of emissions in this case is determined from the chemical's 90 percent evaporation time.
Product Placed in Environment - Constant Rate Model. For a product placed in the
environment, such as a solid air freshener, the chemical is assumed to emit at a constant rate over a
duration that depends on its molecular weight and vapor pressure. If this duration exceeds the user-
specified duration of use, then the chemical emissions are truncated at the end of the product-use period,
because the product is assumed to be removed from the house after the use period.
Product Contacts Skin Directly - Potential and Absorbed Dose. For a product that comes in
direct contact with the skin, the dermal portion of the User-Defined scenario allows you to model dermal
exposure based on potential or absorbed doses. Potential dose is the amount of a chemical contained in
bulk material that is applied to the skin. Absorbed dose is the amount of substance that penetrates the
absorption barriers of an organism. CEM can calculate absorbed dose for aqueous media using a
permeability coefficient. The permeability coefficient is a flux value, normalized for concentration that
represents the rate at which the chemical penetrates the skin.
If you elect to calculate the absorbed dermal dose rate for an aqueous media, you will have to
enter a permeability coefficient (Kp). The program gives you three options: "Pick Permeability
Coefficient From List," "Enter Known Permeability Coefficient" and "Estimate Permeability Coefficient
From Known Kow." If you select "Pick Permeability Coefficient From List" another screen will prompt
3-77
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you to select from a list of chemicals contained in the 1992 EPA document entitled Dermal Exposure
Assessment: Principles and Applications (U.S. EPA, 1992d). If the you select "Enter Known
Permeability Coefficient" or "Estimate Permeability Coefficient From Known Kow", you must enter a
selected value in units of cm/hr. More information on the permeability coefficient's relationship to Kow
can be found in Section 3.3.8.2.
3.3.2.3 Exposed Population
The age group that appears in the box on the right side of the Scenario page (Figure 3-32) is the
exposed population selected on the Screening Level Main page (Figure 3-1). These age groups include:
adults, youths 13 to 19 years, children 6 to 12 years, small children 3 to 5 years, infants 1 to 2 years, or
infants less than one year old. However, the only scenarios for which you can calculate dermal exposure
for a youth, infant or child are the Bar Soap and the User-Defined Scenarios. Dermal exposures for non-
adults in the remaining scenarios are not calculated because the scenarios assume active and not passive
exposure (e.g., adults are assumed to engage in cleaning and house painting activities; children are not),
and individuals other than adults are assumed to have no direct contact with these products. Non-adults
(youths, children, small children and infants) have significant changes in their physical qualities (e.g.,
body weight, surface area) over time. Therefore, for non-adults, CEM will calculate acute dermal
exposures for the Bar Soap and User-Defined scenarios only. Although you can calculate chronic
exposure for non-adults in the User-Defined scenario, these results may not reflect realistic exposures. In
general, for inhalation scenarios, adults are assumed to be actively exposed (i.e., during product use);
non-adults are assumed to be passively exposed.
When you select a scenario or an exposed population, only those inputs pages which are
applicable can be selected, and that type of exposure assessment will be performed (e.g., if air freshener is
selected, the dermal inputs page may not be selected because no dermal inputs are needed for this
scenario).
3.3.3 Inhalation Input Page
To calculate inhalation exposure to a consumer product, enter the information requested on the
Inhalation Inputs screen (Figure 3-34). Default exposure factor values, derived from EPA's Exposure
Factors Handbook (1997) (See Table 3-2 in Section 3.1.2) appear in the appropriate fields, depending on
the scenario you have selected. All values contained within the white boxes on the Inhalation Inputs page
may be edited by the user.
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S3 Consumer Exposure Module (CEM)
File Run Model Help
Inhalation Inputs
Introduction Scenario Inhalation Input Day of Use I Days After Use Dermal Input
Scenario: Latex Paint
This screen allows the user to input the required product parameters for the inhalation
model, (potential dose estimate)
Identification Number: 1123502 Product: versatone
Frequency of Use (chronic):
Frequency of Use (acute):
Mass of Product
per Event • Central Tendency
Duration of Event
¦ Central T endency
Air Exchange Rate
Inhalation Rate
During Use
Inhalation Rate
After Use
4 events/year Exposure Duration (chronic): |~~
1 event/day Exposure Duration: (acute)
M ass of Product U sed r-
per Event - High-End '
Duration of Event
- High-End '
Body Weight
3G35 9
3 hrs/ev
"77 air xchgs
0 45 per hour
r
1,1 m3/hr Averaging Time (chronic) |
Averaging Time (acute)
11 years
1 day
1.272e+04 g
8 hrs/ev
71.8 kg
1 day
Quick Assist
Figure 3-34. Inhalation Input Page
The following are short descriptions of the variables required for the Inhalation portion of CEM:
Frequency of Use (Chronic exposures) — number of times per year the selected activity or
scenario is performed (events per year).
Frequency of Use (Acute exposures) — number of times per day the selected activity or
scenario is performed (CEM assumes 1 event per day).
Exposure Duration (ED) — Duration of product use (years for chronic, 1 day for acute)
Mass of Product Used per Event (Central Tendency) — default value is 50th percentile
amount of product used per activity or scenario (g).
Mass of Product Used per Event (High-End) — default value is 90th percentile amount of
product used per activity or scenario (g).
Duration of Event (Central Tendency) — default value is 50th percentile amount of time it
takes to complete the selected activity or scenario (hours per event).
Duration of Event (High-End) — default value is 90th percentile amount of time it takes to
complete the selected activity or scenario (hours per event).
Air Exchange Rate — number of times over a specified period that the air leaves and enters the
room where the activity or scenario occurs (air exchanges per hour).
Body Weight — weight of the Exposed Population individual (kg).
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Inhalation Rate During Use — inhalation rate of the Exposed Population individual during the
application of the product (rrr/hr).
Inhalation Rate After Use — inhalation rate of the Exposed Population individual after the
application of the product (rrr/hr).
Portion of Aerosol in the Air (Fabric Protector and Aerosol Paint scenarios only) — fraction
of the product that remains in the air as an aerosol during the product's use (unitless).
Averaging Time (Chronic) — period of time over which exposures are averaged. For cancer,
this number is generally assumed to be the lifetime of the product user (defau lt is 75 years) and is
used in calculating the Lifetime Average Daily Dose.
Averaging Time - (Acute), (Scenario dependent) — period of time over which exposures are
averaged. For acute toxicity in the exposed population, this value is assumed to be 1 day.
3.3.4 Day of Use Input Page
The Day of Use Input page (Figure 3-35) allows you to select vanous activities that the exposed
individual would be performing during the day on which the consumer product is being used. The page
consists of 26 drop-down lists, 24 that represent each hour of the day to record the location of the exposed
individual throughout the course of the day, 1 that allows you to select the room where the product is
used, and 1 that allows you to select the start time of the product use. This page also contains the volume
of the room where the product is used (Zone 1 volume) and the volume of the house. The Day of Use
Input page is used only for inhalation exposure assessments.
S3 Consumer Exposure Module (CEM)
Day of Use Data
MB
File Run Model Help
Introduction Scenario Inhalation Input Day of Use Days After Use I Dermal Input
Scenario: Latex Paint
12:00 Midnight
1:00 AM
2:00 AM
3:00 AM
4:00 AM
5:00 AM
6:00 AM
7:00 AM
8:00 AM
9:00 AM
10:00 AM
11:00 AM
Quick Assist
|1. Bedroom
d

11. Bedroom
d

1. Bedroom

|1. Bedroom
a

|1. Bedroom
d
|1. Bedroom
i

12. Kitchen
d

13. Bathroom
d

|1. Bedroom
d

1. Bedroom
d
12:00 NOON
1:00 PM
2:00 PM
3:00 PM
4:00 PM
5:00 PM
6:00 PM
7:00 PM
8:00 PM
9:00 PM
10:00 PM
11:00 PM
1-Bedroom 3 Room of Use
1. Bedroom I F • Bedroom ^
1. Bedroom
4. Living Room
"3
"3]
~3
3 F
~3
Zone 1 Volume
| 40 m3
Whole House Volume
369 m3
Start Time
"3
, , ¦ • -| Note: Except for the Solid
4. Living Room Air Freshen; scenario, the
user must be in the Room
of Use for the selected
4. Living Room
Duration of Use.
"3
Note: Day of Use data is only applicable for the inhalation model.
Figure 3-35. Day of Use Input Page
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You can select from seven different activity locations: bedroom, kitchen, bathroom, living room,
utility room, car, and out (outside the house). The table below lists the volumes of each activity location
and its corresponding air exchange rate. There is no defined volume for "out" because exposure is
assumed to be zero.
Activity
Location
Estimated
Volume, m3
Reference
Air
Exchange
Rate (hr')
Reference
Bedroom
40
Versar, 1989
*
*
Kitchen
20
U.S. EPA, 1987c
*
*
Bathroom
9
U.S. EPA, 1987c
*
*
Living Room
40
U.S. EPA, 1987c
*
*
Utility Room
20
Assumed to be
analogous to kitchen
volume
*
*
Car
2.4
Versar, 1986
12.5
Versar, 1986 (assumes half of exchange rate for
car at rest with engine running)
Whole House
369
U.S. EPA, 1997
0.45
U.S. EPA, 1997
* Whole house air exchange rate applies to all locations except "car."
The Room of Use input selections are the same as the activity locations, except for "out," which
is not an option for the room of use. CEM sets the selection by default.
To begin, select the room of use and start time before entering the hourly locations (activity
patterns). Make sure the room of use and start time correspond to the activity location of the exposed
individual at that time; that is, you cannot select the bedroom as the room of use at a start time of 12:00
noon when the activity pattern for that time indicates the individual exposed is in the bathroom.
The model also will automatically change an activity location depending on the 90th percentile
Duration of Use input on the Inhalation Input page; that is, if the scenario requires the individual to be
exposed for 4 hours, CEM automatically changes the activity location so that 4 hours correspond to the
room of use and the start time. If you attempt to change the location in this 4 hour block of time, the
system will alert you that the room of use will be changed.
For scenarios modeling passive exposure of youths, infants or children, the default activity
pattern of the day of use will be nearly identical to the day after use (non-use day) activity pattern for the
user (adult). The infant or child will initially be placed (by default) outside the room of use during the
time the product is being used. You can move the infant or child to any room at any time during the day
of use.
Users should note that CEM requires that, except for the Solid Air Freshener scenario, the
Duration of Use, both central tendency and high-end, must occur in its entirety during the Day of Use.
CEM was not designed to model product-use durations that continue into the next day (e.g. indoor
painting that starts at 10 PM and ends at 2:00 AM). If the user models this type of scenario, then CEM
will not function properly. In these situations, it is suggested that the user select an earlier start time, such
that the entire use period occurs on the day of use.
3.3.5 Days After Use (Non-Use Days) Input Page
The Days After Use (Non-Use Days) Input Page (Figure 3-36) allows you to select from the same
locations as the Day of Use Input Page. The screen consists of 24 drop-down list boxes to allow you to
fill in the location of the exposed individual during the course of the day or days after use. The Days
After Use (Non-Use Days) Input Page is used only for inhalation exposure assessments.
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S3 Consumer Exposure Module (CEM)
File Run Model Help
Day After Use Data
Introduction Scenario Inhalation Input Day of Use Days After Use Dermal Input
Scenario: Latex Paint
12:00 Midnight 12:00 NOON b Kitchen 3
1:00 AM |l. Bedroom 1:00 PM |4. Living Room ~^\
2:00AM |l. Bedroom 2:00 PM |7. Out
3:00 AM 11. Bedroom 3 3:00 PM [7^ T\
4:00 AM |1. Bedroom ^ 4:00 PM |4. Living Room ]*]
5:00AM Jl. Bedroom ~^\ 5:00PM 12. Kitchen [£]
6:00AM |l. Bedroom 6:00 PM |2. Kitchen
7:00 AM |1. Bedroom 3 7:00 PM |7. Out 3
8:00 AM j3. Bathroom 3 8:00 PM 14. Living Room 3
9:00 AM 12. Kitchen ^ I 9:00 PM 14. Living Room r I
10:00AM 14. Living Room 10:00PM |4. Living Room
11:00AM 14. Living Room 11:00PM |l. Bedroom
Quick Aridst | Mole: Day After Use data is only applicable for the inhalation model.
Figure 3-36. Days After Use (Non-Use Days) Input Page
3.3.6 Dermal Input Page
The Dermal Input page (Figure 3-37) allows you to enter the parameters necessary to calculate dermal
exposure from the consumer product or use default exposure factor values. Default exposure factor
values, derived from EPA's Exposure Factors Handbook (1997) (See Table 3-2 in Section 3.1.2) appear
in the appropriate fields, depending on the scenario you have selected. You can edit all of the entries on
the Dermal Input page except for the identification number, product name, and scenario fields.
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|RSj Consumer Exposure Module fCEMl

File Run Model Help

Dermal Inputs

Introduction Scenario Inhalation Input Day of Use Days After Use Dermal Input

Scenario: Latex Paint

This screen allows the user to input the required product parameters for the
dermal model, (potential dose estimate)

1 dentif ication N umber: 112
3502 Product versatone

Amount Retained on Skin ^
0.0114 g/cm2-event Exposure Duration (chronic) |
11 years

Exposure Duration (acute) -
1 Day

Frequency of Use (chronic) J"
4 events/year =u,raoS Area to Body |
Weight Ratio
4.5 cm2/kg

Frequency of Use (acute)
1 Event/Day

Averaging Time (chronic) - ["
75 years

Averaging Time (acute)
1 Day

Quick Assist |

Figure 3-37. Dermal Input Page
Dermal doses can be categorized as potential doses or absorbed doses. A potential dose is the
amount of a substance ingested, inhaled, or applied to the skin. An absorbed dose is the amount of a
substance penetrating a specific absorption border (e.g., the exchange boundaries of skin, lung, and
digestive tract) of an organism through either physical or biological processes. You can calculate the
absorbed dose for an aqueous media exposure scenario by choosing the User-Defined Scenario on the
Scenario page (Figure 3-32) to determine the permeability coefficient for the chemical of concern. The
permeability coefficient is a flux value, normalized for concentration, that represents the rate at which the
chemical penetrates the skin. The units for the permeability coefficient are centimeters per hour You can
choose a penneability coefficient from a compiled list on the User-Defined Scenario Description screen
(Figure 3-33), enter a known permeability coefficient, or calculate a permeability coefficient from a
known Kow value.
The following are short descriptions of the fields in the Dermal Input page:
Amount Retained on the Skin — amount of product that is retained on the skin (grams of
product per square centimeter of skin surface per event or g/cnr-event). This variable is the
product of the film thickness of the liquid on the skin's surface, the density of the formulation,
and the dilution fraction (grams of product per square centimeter of skin surface per event or
g/cnr-event).
Exposure Duration (ED) — Duration of product use (years for chronic, 1 day for acute)
Frequency of Use (Chronic exposures) — number of times per year the selected activity or
scenario is performed (events per year).
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Frequency of Use (Acute exposures) — number of times per day the selected activity or
scenario is performed (CEM assumes 2 events per day for bar soap hand washing scenario and 1
event per day for all other scenarios).
Surface Area to Body Weight (SA/BW) Ratio — ratio of the surface area of the exposed
population's exposed skin during the scenario to the exposed population's body weight (cm2/kg).
For more information, see the discussion at the end of this section.
Frequency of Use - Hands (Bar Soap Scenario only) — number of times the product is used
and comes in contact with the product user's hands (events per year). This input variable is only
used if you selected the Bar Soap scenario. People use bar soap several times during the course
of a day to wash their hands and generally once a day during bathing. The Frequency of Use
variable becomes the Frequency of Use - Body variable and is used in conjunction with the
Frequency of Use - Hands variable in the Bar Soap scenario.
SA/BW Ratio - Hands (Bar Soap Scenario only) — ratio of the surface area of the exposed
skin of the product user's hands during the scenario to the user's body weight (cm2/kg). This
input variable is only used during the Bar Soap scenario (see Frequency of Use - Hands for
explanation). For more information, see the discussion at the end of this section.
Averaging Time - (Chronic) — period of time over which exposures are averaged. For cancer,
this number is generally assumed to be the lifetime of the product user (default is 75 years) and is
used in calculating the Lifetime Average Daily Dose.
Averaging Time - (Acute), (Scenario Dependent) — period of time over which exposures are
averaged. For acute toxicity in the exposed population, this value is assumed to be 1 day.
Duration of Event (User-Defined Scenario, Absorbed Dose only) — length of time it takes to
complete selected activity or scenario (hours/event). This variable is only used during user-
defined dermal scenarios calculating absorbed dose.
Dilution (User-Defined Scenario, Absorbed Dose only) — ratio of the amount of chemical of
concern to the amount of product (unitless). This variable is only used during user-defined
dermal scenarios calculating absorbed dose.
Density (User-Defined Scenario, Absorbed Dose only) — ratio of the mass of the product to
its volume (g/cm3). This variable is only used during user-defined dermal scenarios calculating
absorbed dose.
To determine potential exposure, the dermal portion of CEM uses a film-thickness approach,
which assumes that exposure occurs from a thin layer of the consumer product on a defined skin surface
area. Data on the actual thickness of films of various products on human skin are limited. The aqueous-
based film-thickness data used in CEM were derived from the 1987 EPA report, Methods for Assessing
Exposure to Chemical Substances: Volume 7, Methods for Assessing Consumer Exposure to Chemical
Substances (1987c); The oil-based film-thickness data used in CEM were derived from the 1992 EPA
report (A Laboratory Method to Determine the Retention of Liquids on the Surface of Hands (1992c).
The 1992 report stated that retention measurements for the aqueous-based liquids presented in the 1987c
report were not uniform and were difficult to reproduce. For these reasons, the 1992 report dropped such
data from further consideration. However, the data under question are still the best known to EPA for
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aqueous dermal exposures, so EPA has decided to retain the data in this model until better data are
available. Because of the uncertainty associated with the amount of product forming a film on the skin,
the dermal exposure estimates are considered less certain than those calculated in the inhalation portion of
CEM. Absorbed dermal dose rates can be calculated using a permeability coefficient or a log
octanol/water coefficient, log Kow, but these values and their use in calculating exposure also involve
uncertainty. Absorbed exposure can only be calculated for the User-Defined scenario in CEM.
Where possible, CEM uses the ratio SA/BW rather than the dermally exposed surface area and
body weight because there is a direct relationship between the surface area of an individual and his or her
body weight. Combining surface area distributions with unrelated body weight data may lead to biases in
estimating exposures (Phillips et al., 1993). For example, combining an upper-percentile surface area
value with a median or lower-percentile body weight could result in an unrealistic body type (i.e., an
unrealistically tall individual). SA/BW ratios for adults and children (ages <1 years and 1-2 years) in
CEM are derived from subsets of direct measurements of surface area and body weight data from 401
individuals (U.S. EPA, 1985b); for example, matched hand surface areas and body weights from 32 men
and 12 women were used to develop the SA/BW ratios for adult hand dermal exposures. The measured
body weight data from these individuals are different from those used to calculate the default body
weights presented in Table 3-2 and used in E-FAST/CEM potential ingestion and inhalation dose
calculations, so attempts to back-calculate surface areas in dermal dose calculations with the default body
weight data are not valid. SA/BW ratios calculated in this way (i.e., from matched direct measurements)
were not available for children ages 3-5 years, 6-12 years, and 13-19 years. Thus, the SA/BW ratios for
these age groups were developed using median surface area data for each age group from EPA's
Exposure Factors Handbook (U.S. EPA, 1997) divided by the mean body weight for these age groups.
Note that in most cases dermal exposures in CEM applies only to adults actively engaged in product use.
(e.g., children are not assumed to engage in house cleaning or painting activities). The SA/BWs used
differ depending on scenarios. For example, some scenarios assume that only the palms of the hands are
exposed while others assume whole hand exposure or that some other portion of the body is dermally
exposed (See Section 3.3.2.1 for details.) The exception is in the Bar Soap scenario which also applies to
all ages of children.
3.3.7 Estimation of Indoor Air Concentrations
CEM predicts indoor air concentrations by implementing a deterministic, mass-balance
calculation. The model uses a two-zone representation of a house, with zone 1 representing the area
where the consumer product is used (e.g., a kitchen) and zone 2 being the remainder of the house. The
modeled concentrations in the two zones are a function of the time-varying emission rate in zone 1, the
volumes of zones 1 and 2, the air flows between each zone and outdoors, and the air flows between the
two zones. For a conservative estimate of exposure, indoor sinks are assumed not to exist.
The model requires the conservation of pollutant mass as well as the conservation of air mass.
CEM uses a set of differential equations whereby the time-varying concentration of the chemical in each
zone is a function of the rate of pollutant loss and gain for that zone. These relationships can be
expressed as follows (Sandberg, 1984):
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3.3.7.1 Pollutant Mass Balance
Change in Pollutant Mass , ,, , „ * \ D , , ,, .. CFn
2 4 Production ± lransport ) Removal ± Reactions *CLI•
Change in Time
Neglecting reactions:
dMass
dt
Sources + ^ /Wav.S' in - ^ Mav.S' out ± ^ ,S7/?A'.s (Eq. 3-36)
Or:
vi~jf = YjSources+X - Z( ± Z 'S7/?A'V (Eq-3-37)
where:
Cair = Air concentration
Q = Flow rate
V = Volume of the zone
iandj = Two indoor zones plus outdoors
The "±" for sinks accounts for the possibility that they may be reversible. As noted above, sinks are
ignored in CEM, but are shown here for completeness.
3.3.7.2 Air Mass Balance
E Flows into a zone 4 E Flows out of a zone (Eq. 3-38)
Or:
E Qij 4 E Qji (Eq. 3-39)
where Q, i, and j are defined as in Equations 3-35 through 3-37.
The flow rates are input as constants. The pollutant mass balance (Equation 3-37) is used in conjunction
with the flow rates to predict the time-varying pollutant concentrations in each of the two indoor zones.
The differential equations can be solved by a variety of numerical methods. The fourth-order
Runge-Kutta method (also referred to as the Kutta-Simpson equation) is used for temporal integration
(Mathews, 1992). Although this method is not as computationally efficient as some others, it is very
stable, self-starting, and accurate. The equation takes the following form:
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C{t + At) = C(t) +\/6[K\+ 2K2 + 2K3 + K4]
(Eq. 3-40)
where:
K1 = dC (At), evaluated at time = t, C = C (t)
dt
K2 = dC (At), evaluated at time = t + (At)/2, C = C (t) + Kl/2
dt
K3 = dC (At), evaluated at time = t + (At)/2, C = C (t) + K2/2
dt
K4 = dC (At), evaluated at time = t + (At), C = C (t) + K3.
dt
The Runge-Kutta technique has been evaluated for stability over a wide range of values for time step,
zone volumes, and flow rates.
How a product's chemical emissions are represented in CEM depends on how the product is used
and its chemical makeup. Emissions are estimated over a period of 60 days using the following equations
and methods that account for how a product is used or applied, the total applied mass of the product, the
weight fraction of the chemical in the product, and the molecular weight and vapor pressure of the
For a product that is applied to surface, such as a general purpose cleaner or a latex paint, an
incremental source model is used. This model assumes a constant application rate over the specified
duration of use; each instantaneously applied segment has an emission rate that declines exponentially
over time, at a rate that depends on the chemical's molecular weight (MW) and vapor pressure (VP).
In the case of a general purpose cleaner, the equation for exponentially declining emissions for
each instantaneously applied segment is as follows:
where E (t) is the emission rate (mass/time) at time t (in hours), E (0) is the initial emission rate at time 0,
k is a first-order rate constant for the emissions decline (inverse hours), and t is elapsed time (hours). The
value of k is determined from an empirical relationship, developed by Chinn (1981), between the time (in
hours) required for 90 percent of a pure chemical film to evaporate (EvapTime) and the chemical's
molecular weight and vapor pressure:
chemical.
(Eq. 3-41)
EvapTime
145
0.9546
(Eq. 3-42)
The value of k is determined from the 90 percent evaporation time as follows:
(Eq. 3-43)
EvapTime
3-87
-------
E (0) can be determined from the fact that the integral of Equation 3-41, which accounts for all chemical
mass released (i.e., applied mass times chemical weight fraction), is equal to E (0)/k. However, the
equation for the time-varying emission rate resulting from the combination of constant application and
exponentially declining emissions (Evans, 1994) requires knowledge of only the total mass released and k.
ER(t) = -^[(1- <¦-")- (1- e-"-") x
(Eq. 3-44)
where:
ER(t) = Emission rate at time t (mg/hr)
M = Chemical mass to be emitted (mg)
ta = Application time (hr)
k = First-order rate constant for emissions decline (1/hr); see Eq. 3-43
t = Time (hr)
H(t_ta) = 0 if t-ta < 0
= 1 if t-ta > 0
Latex paint is handled much like a general purpose cleaner, with two exceptions: (1) a double
exponential model is used to account for an initial fast release that is governed primarily by evaporation,
followed by a slow release dominated by diffusion; and (2) only 25 percent of the applied chemical mass is
released, because a substantial fraction of the mass becomes trapped in the painted substrate when it dries.
Empirical studies reported by Wilkes et al. (1996) support the assumption of 25 percent mass released and
have estimated a relationship between the fast rate of decline (kl) and vapor pressure (VP), and between the
slow rate of decline (k2) and molecular weight, leading to the following equation for the time-varying
emission rate (Evans, 1994):
ER(t) = y-x ([/ x (i" e~ku) + (l - /) x (1 - e~k2t)
where:
[/ x (1 - e-kl{t~ta)) + (1 - /) x (1 - e-k2{t~ta)) - 1
(Eq. 3-45)
X H(t-ta)
ER(t) =
Emission rate at time t (mg/hr)

M
Chemical mass to be emitted (0.25
x mass of product) (mg)
ta =
Application time (hr)

f
Fraction of mass emitted from first
exponential (0.1) (unitless)
t
Time (hr)

H(t-ta)
0 if t-ta < 0

1 if t-ta > 0

kl
233.25 x VP/24 (1/hr)

k2
0.0000584 x MW/24 (1/hr)

VP
Vapor pressure (torr)

MW =
Molecular weight (g/mol)

The equation for the resultant emission profile requires estimates of the total mass released, kl and k2, and
the fraction of released mass associated with the first exponential (Evans, 1994). Based on the empirical
studies reported by Wilkes et al. (1996), CEM associates 10 percent of the released mass with the first
exponential.
For a product sprayed on a surface, such as a fabric protector or an aerosol paint, a portion of the
applied chemical mass (default of 1 percent) is assumed to be aerosolized and is therefore immediately
available for uptake by inhalation. The remainder is assumed to contact the target surface and to
subsequently volatilize at a rate that depends upon the chemical's molecular weight and vapor pressure.
The constant emission rate (ER, in mass/time) for the aerosolized portion is as follows:
_ Applied Chemical Mass x Fraction Aerosolized (Eq. 3-46)
Duration of Product Use
3-88
-------
The remaining (non-aerosolized) chemical mass is treated in the same manner as described above for a
general purpose cleaner, combining a constant application rate with an exponentially declining rate for
each instantaneously applied segment.
For a product added to water, such as a laundry detergent, the chemical is assumed to emit at a
constant rate over a duration that depends on its molecular weight and vapor pressure. If this duration is
longer than the user-specified duration of use, then the chemical emissions are truncated at the end of the
product use cycle (i.e., in the case of a washing machine, the remaining chemical mass is assumed to go
down the drain).
The potential duration of emissions in this case is determined from the chemical's 90 percent
evaporation time, as in Equation 3-42. The constant emission rate (ER) is
_ Chemical Mass (Eq. 3-47)
EvapTime
It is possible, however, for evaporation time to be longer than the duration of product use. In that case,
the emission rate in Equation 3-47 is applied only through the end of the use cycle, resulting in loss of
some mass down the drain before evaporation time is reached.
For a product placed in the environment, such as a solid air freshener, the chemical is assumed to
emit at a constant rate over a duration that depends on its molecular weight and vapor pressure. If this
duration exceeds the user-specified duration of use, then the chemical emissions are truncated at the end
of the product-use period, because the product is assumed to be removed from the house after the use
period. Equation 3-47 applies equally here, with the loss of some mass when evaporation time is longer
than the use cycle.
In certain cases the above source models could lead to predicted concentrations that exceed the
chemical's saturation concentration in air. However, the model adjusts the time-varying emission rate so
that the saturation concentration is never exceeded. In such cases, the chemical mass will be released at a
slower rate than implied by the above source models, once the saturation concentration is reached. The
same chemical mass ultimately will be released, except in cases where emissions are truncated at the end
of the product use period.
The following equation is used to estimate the value for the saturation concentration:
VP x CF1 x MW x CF2 x CF3 (Eq. 3-48)
where:
Csal = Saturation concentration (mg/m3)
VP = Vapor pressure (mm Hg)
MW = Molecular weight (g/mol)
R = Gas constant = 0.0821 L-atm/mol-K
T = Temperature of the air (296 K)
CF1 = Conversion factor (atm/760 mmHg)
3-89
-------
CF2 = Conversion factor (103 mg/g)
CF3 = Conversion factor (103 L/m3)
At each time step CEM checks whether the current value for the emission rate results in an indoor
concentration that exceeds Csat, If so, then the emission rate is reduced to a value that results in the indoor
concentration equaling Csat. In such a case, CEM keeps track of the cumulative mass that has been
subtracted to meet the Csat constraint. Release of this accumulated excess mass is initiated at a later point
in time, when the modeled concentration otherwise would be below the Csat value. This procedure is
continued until all excess mass has been release, unless the model run period of 60 days ends first (or the
product is removed or goes down the dram).
3.3.8 Estimation of Consumer Exposures
After you have entered the applicable information in the various input pages (as described above),
click on "Run Model" on the pull-down bar at the top of the screen and then click on "Submit Data." to
calculate the consumer exposures for the scenario of interest. CEM prompts you with a pop-up box when
it is finished with the calculations; Click "OK" to display the results screen. The first page (Figure 3-38)
displays the values you entered as inputs in the various scenario input pages. The remaining page(s)
display the exposure estimates for the inhalation and dermal results, as applicable. Figure 3-39 is an
example of the CEM Inhalation Exposure Estimates page, and Figure 3-40 is an example of the CEM
Dermal Exposure Estimates page. The following sections (3.3.8.1 and 3.3.8.2) discuss the calculation of
these exposure estimates. For further discussion regarding inhalation concentration and dose estimation,
please refer to Appendix D.
0 Consumer Exposure Module (CEM)
File Run Model Help
QBE
Inputs J Outputs - Inhalation | Outputs - Dermal |
Return to Input Screen
ID Num: 1123502
CBul Inputs

Product: versatone
Chemical Name: versatone

Scenario: Latex Paint

Population: AJult

totolecular Weight (gtoole)
Consumer Product Weight Fraction
- Central Tendency
222
0.1
VP florr) 0.0004
Consumer Product Weight Fraction - High-Bid
0.3
Inhalation Inputs
Frequency of Use (chronic) (events/yr)
4
Exposure Duration (chronic) (years)
11
Frequency of Use (acute) (events/day)
1
Exposure Duration (acute) (days)
1
futass of Product Used - Central Tendency (g)
3635
totass of Product Used - High-Bid (g)
1.272e+04
Inhalation Rate During Use (m3rtir)
1.1
Inhalation Rate .After Use (m3/hr)
0.55
Zone 1 Vblume (m3)
40
Whole House Vblume (m3)
369
Duration of Event - Central Tendency (hrs/ev)
3
Duration of Eirent - High-Bid (hrs/ev)
8
Ar Exchange Rate (air xchgs/hr)
0.46
Body Weight (kg)
71.8
Astivity Patterns
User: 11111112 3 1111111
1 274441
Start Time:
10
Non-User: 111111113244247742274441
Room of Use:
. Bedroom
Hour: 0 6 12
18

Dermal Inputs
Frequency of Use (events/yr) Chronic
4
S/VBW (cm2/kg)
4.5
Frequency of Use (events/day) acute
1

Anount Retained/Absorbed to Skin (g/cm2-event)
0.0114

Exposure Duration (chronic) vears
Exposure Duration (acute) days
11
1

Averaging Time (chronic)
2.74e+04
days

Averaging Time (acute)
1.00e-t00
days

Figure 3-38. CEM Inputs
3-90
-------
S3 Consumer Exposure Module (CEM]
File Run Model Help
Inputs [TQutg^s^lnBal^jonJ Outputs - Dermal
Return to Input Screen
CBM Inhalation Exposure Estimates
Product: versatone
Scenario: Latex Paint
Population: Adult
Inhalation Rate(m3rtir)
BodyWeight (kg)
Exposure Duration (years) Chronic
Exposure Duration (days) .Acute
Frequency of Use (events/vear) Chronic
Frequency of Use (events/day) .Acute
Exposure Units
Result
AT (days)
Chronic, Cancer

LAOD ^(mg/kg-day)
1,72e-03
2.74e-t04
LADC ^(mg/mS)
9.36e-03
2.74e+04
Acute

/vDR^mgfcg-day)
3.62e-01
1 .OOe-tOO
LADDpot - Lifetime A/erage Daily Dose (mg/kg-day)
LADCpot - Lifetime Average Daily Concentration (mgAn3)
ADRpot - .Acute Dose Rate (mg/kg-day) Cppot • Peak Concentration (mgAn3)
Note: 75 years = 2.738e+{)4days pot - potential dose
Note: The general Agency guidance for assessing short-term, infrequent events (for most chemicals, an exposure of less than
24 hours that occurs no more frequently than monthly) is to treat such events as independent, acute exposures rather than
as a chronic exposure. (Methods for Exposure-Response Analysis for Asute Inhalation Exposure to Chemicals
(Eternal Review Draft). EPA/600/R-98/D51. .April 1998)
Figure 3-39. CEM Inhalation Exposure Estimates
S3 Consumer Exposure Module (CEM)
File Run Model Help
Inputs | Outputs - Inhalation |
Return to Input Screen
CBul Dermal Exposure Estimates
Product: versatone
Scenario: Latex Paint
Population: .Adult
Exposure Duration (years) chronic
Exposure Duration (days) acute
SA'BW (cntf.'kg)
Frequency of Use (eventsfyear) chronic
Frequency of Use (events/day) acute
Exposure Units
Result
AT (days)
Chronic, Cancer

LADD ^(mgrtxg-day)
8.25e-03
2.74e+04
.Acute

•ADR ^(mg^g-day)
1.54e+01
1.00e-»00
LADDpot • Ufetime Average Daily Dose (mg/kg-day)
.ADRpot ¦ Acute Dose Rate (mg/kg-day)
pot - Potential Dose
Note: 75 years = 2.738e-t04 days
Note: The general Agency guidance for assessing short-term, infrequent events (for most chemicals, an exposure of less than
24 hours that occurs no more frequently than monthly) is to treat such events as independent, acute exposures rather than
as a chronic exposure. (Methods for Exposure-Response Aialysis for Aiute Inhalation Exposure to Chemicals
(External Review Draft). EPA«00/R-98*I51. .April 1998)
Figure 3-40. CEM Dermal Exposure Estimates
3-91
-------
3.3.8.1 Estimation of Inhalation Exposures
Two different inhalation dose calculations are performed in CEM: the Potential Lifetime Average
Daily Dose (LADDP0T ) and the Potential Acute Dose Rate (ADRP0T). The general expression for the
Potential Lifetime Average Daily Dose (LADDP0T ) is as follows:
C . x InhR x FQ x DEv x ED (Eq. 3-49)
LADDpnr=—
POT BW x AT x CF1
where:
LADDpot = Potential Lifetime Average Daily Dose (mg/kg-day)
Cair = Exposure concentration (mg/m3)
InhR = Inhalation rate (m3/hr)
FQ = Frequency of product use (events/year)
DEv = Duration of an event (hr/event)
ED = Exposure duration (years of product usage; see Table 3-2)
BW = Body weight (kg)
AT = Averaging time (years)
CF1 = Conversion factor (365 days/year)
Within CEM, the inhalation dose is calculated iteratively, in time steps of 10 seconds, taking into account
the chemical emission rate over time, the volume of the house and each zone, the air exchange rate and
interzonal airflow rate, and the exposed individual's locations and inhalation rates during and after
product use. Because of this iterative process, Equation 3-49 may not be directly used to calculate the
LADDpot from the LADCP0T presented in the model results. Therefore, the LADDP0T is calculated using
the following expression:
Dosentj x FQ x ED (Eq. 3-50)
LADDpnT = ^V 4 '
POT BW x AT x CF1
where the variables are defined as they are for Equation 3-49, and Doseatl is the time-integrated, air dose
for an event given by Equation 3-51. For LADDP0T calculations, the averaging time is the lifetime of the
individual.
ET
Doseatl = X (Clt xA/x InhR,, x CF2) (Eq' 3-5!)
ST
where
Doseatl = Time-integrated air dose for an event (mg/event) from start time (ST) to
end time (ET), where ET = ST + 60 days.
Cj t = Concentration in Zone i at time t (mg/m3)
• t = time interval (1.16 x 10"4 days/event)
InhR t = Inhalation Rate for Zone i at time t (m3/hr)
CF2 = Conversion factor (24 hours/day)
For cases where the evaporation time estimated in Equation 3-42 exceeds 60 days, the model will
truncate the emissions at 60 days. Conversely, for cases where the evaporation time is less than 60 days,
emissions will be set to zero between the end of the evaporation time and 60 days.
The general expression for the Potential Acute Dose Rate (ADRP0T) is as follows:
C . x InhR x FQ x DEv x ED
j air
POT BW*AT (Eq- 3"52)
3-92
-------
where:
adrpot
= Potential Acute Dose Rate (mg/kg-day)
c
^air
= Exposure concentration (mg/m3)
InhR
= Inhalation rate (m3/hr)
FQ
= Frequency of product use (events/year)
DEv
= Duration of an event (hr/event)
ED
= Exposure duration (years of product usage; see Table 3-2)
BW
= Body weight (kg)
AT
= Averaging time (days)
For the ADRP0T calculations, an averaging time of one day is used; the ADRP0T therefore represents the
maximum time-integrated dose over a 24-hour period during the exposure event.
As was the case with the LADDP0T in Equation 3-49, Equation 3-52 cannot be directly used to
calculate an ADRP0T from a time-integrated air concentration. Instead, the following expression is used:
ADR = Doseati x FQ x ED (Eq 3.53)
where
BW x AT
ADRpot = Potential Acute Dose Rate (mg/kg-day)
Doseatl = Time-integrated, air dose (mg/event)
FQ = Frequency of product use (1 event/day)
ED = Exposure duration (1 day)
BW = Body weight (kg)
AT = Averaging time (1 day)
The time-integrated air dose is defined by the following equation
Doseati = Max
24
^(Citx A tx Inhl\ t x CF2)
(Eq. 3-54)
ST
where
Doseatl = Time-integrated air dose for an event (mg/event) evaluated from start
time (ST) to end time (ET), where ET = ST + 60 days.
Cj t = Concentration in Zone i at time t (mg/m3)
• «t = time interval (1.16 x 10"4 days/event)
InhR t = Inhalation Rate for Zone i at time t (m3/hr)
CF2 = Conversion factor (24 hours/day)
For cases where the evaporation time estimated in Equation 3-42 exceeds 60 days, the model will
truncate the emissions at 60 days. Conversely, for cases where the evaporation time is less than 60 days,
emissions will be set to zero between the end of the evaporation time and 60 days.
The exposure concentration in the above equation is calculated differently for ADRP0T than for
LADDpot. For the LADDP0T calculations, CEM uses the central tendency consumer product weight
fraction, duration of use, and mass of product used. In the ADRP0T calculation, it uses the high-end
consumer product weight fraction, duration of use, and mass of product used. CEM calculates all possible
ADRs, over the 60-day modeling period, as running 24-hour integrations (i.e., hours 1-24, 2-25, etc.), and
then reports the highest of these computed values as the ADR.
3-93
-------
Two different inhalation concentration calculations are performed in CEM: Potential Lifetime
Average Daily Concentration (LADCP0T), and Potential Peak Concentration (Cp P0T). They are defined as
follows:
LADCPor = C"" X ',Q X ED (Eq. 3-55)
AT x CF1 where:
LADCpoi
Potential Lifetime Average Daily Concentration (mg/m3)
cati
Time-integrated air concentration per product-use event

(mg/m3-days/event)
FQ
Frequency of use (events/year)
ED
Exposure Duration - duration of product use (years) (see Table 3-2)
AT
Averaging time (years)
CF1
Conversion factor (365 days/year)
The time-integrated air concentration is estimated using the following equation
ET
where
= (Eq. 3-56)
ST
Cati = Time-integrated air concentration for an event (mg/m3-days/event) from
start time (ST) to end time (ET), where ET = ST + 60 days.
CLl = Concentration in Zone i at time t (mg/m3)
• t = time interval (1.16 x 10"4 days/event)
For cases where the evaporation time estimated in Equation 3-42 exceeds 60 days, the model will
truncate the emissions at 60 days. Conversely, for cases where the evaporation time is less than 60 days,
emissions will be set to zero between the end of the evaporation time and 60 days.
The potential peak concentration (CpP0T) provided in the model output is defined as the highest
instantaneous air concentration that is calculated by the model during any 10-second time step, and
should not be interpreted as a daily maximum concentration. CpP0T is estimated using the following
equation:
CpPoT = Max(Cit)
(Eq. 3-57)
3-94
-------
where
CPpot = Potential Peak Concentration (mg/m3), evaluated as the maximum CLl
from t=0 to t=ET
CLl = Concentration in Zone i at time t (mg/m3)
3.3.8.2 Estimation of Dermal Exposures
Two different dermal exposure calculations are performed in CEM: the Potential Lifetime
Average Daily Dose (LADDP0T ) and the Potential Acute Dose Rate (ADRP0T). The following equations
are used to calculate these results:
T AR x SAJBW x FQ x ED x WF x CF1
LADDpnT = — (Eq. 3-58)
POT AT x CF2 4
,nB AR x SA/BW x FQx ED x WF x CF1
ADRPOt = ^ (Eq. 3-59)
where:
AR
= Amount retained on the skin (g/cm2-event)
SA/BW
= Surface area to body weight ratio (cm2/kg)
FQ
= Frequency of use (events/year for LADDP0T, 1 event/day for ADRP0T

(iexception: 2 events/day for Bar Soap (hand) scenario))
ED
= Exposure Duration-duration of product use (years for LADDP0T, 1 day

for ADRpot ) (see Table 3-2)
WF
= Weight fraction of chemical in product (unitless) - central tendency for

LADDpot, high-end for ADRP0T
AT
= Averaging time (years for LADDP0T, 1 day for ADRP0T )
CF1
= Conversion factor (103 mg/g)
CF2
= Conversion factor (365 days/year)
In the dermal calculations for Bar Soap, the SA/BW term and the FQ term is split into two terms,
a SA/BW and FQ for the body and a SA/BW and FQ for the hands. The dose for the body and hands is
calculated and then summed to provide an overall dose for Bar Soap.
The consumer product weight fraction (WF) term in the above calculations varies. For the LADD
calculations, the central tendency consumer product weight fraction is used. In the ADRP0T calculation,
the high-end consumer product weight fraction is used.
The above calculations are performed for scenarios to calculate the potential dose. Potential dose
is the amount of a chemical contained in bulk material applied to the skin. In the User-Defined scenario
you can select to calculate absorbed dermal exposure using the permeability coefficient method.
Absorbed dose is the amount of substance penetrating across the absorption barriers of an organism. You
can choose a permeability coefficient by one of three methods:
3-95
-------
Entering a permeability coefficient
Selecting a permeability coefficient value from a list of common chemicals
Entering a Kow value and having the model calculate the permeability coefficient using the
following equation (U.S. EPA, 1992d):
log(Kp) = -2.72 + 0.71 x log(Kow)~ 0.0061 x MW
(Eq. 3-60)
where:
Kp = Permeability coefficient (cm/hr)
Kow = Octanol/water partition coefficient (unitless)
MW = Molecular weight (g/mol)
The permeability coefficient is then entered into the following equations to calculate dermal exposure:
T Kp x DEv x Dil x Den x SA/BW x FQ x ED * WF x CF1 _ _
LADD^ = ———^ (Eq. 3-61)
ABS AJ, x cp2 V 4 )
ADR _ Kp x DEv x Dil x Den x SA/BW x FQ x ED x PfF x CF1 (E 3_62)
abs y '
where:
KP
DEv
Dil
Den
SA/BW
FQ
ED
WF
AT
CF1
CF2
Permeability coefficient (cm/hr)
Duration of an event (hr/event)
Dilution (unitless)
Density (g/cm3)
Surface area to body weight ratio (cm2/kg)
Frequency of use (events/year for LADDA|;s. 1 event/day for ADR/U;S)
Exposure Duration-duration of product use (years for LADDA|;S. 1 day
for ADRabs ) (see Table 3-2)
Weight fraction of chemical in product (unitless) - central tendency for
LADDabs, high-end for ADR M;s
Averaging time (years for LADDA|;s: 1 day for ADRa,;s)
Conversion factor (103 mg/g)
Conversion factor (365 days/year)
This approach assumes a constant supply of product on the skin throughout the exposure
duration.
3-96
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3.4 Probabilistic Dilution Model (Stand-alone PPM)
PDM is a software program developed by OPPT to predict downstream chemical concentrations
from an industrial discharge. PDM calculates the probability that a given target stream concentration will
be exceeded, and the number of days per year the exceedence condition will likely occur. PDM analyses
can be performed on reaches with measured flow data (i.e., from U.S. Geological Survey gaging stations)
or reaches with only estimated flow values. PDM does not estimate exceedences for chemicals
discharged to still waters, such as bays, lakes, or estuaries. PDM may be executed within the General
Population Exposure and Down-the-Drain modules or may be run as a stand-alone model from the PDM
module. An example of the Stand-alone PDM Site-Specific Results page is shown in Figure 3-41.
17 Screening Level Results
Mil
PDM Site | PDM SIC Code |
PDM Site-Specific Page
Release Number:
Help
Note: this is an active site.
"3]
NPDES Number:
Release Activity:
Facility Name:
Facility Location:
Reach Number:
Reach Name:
Facility on Reach?
Gaging Station ID
Gaging Station Period of Record
Gaging Station Number of Observations
New Release Number
J Clear Page
]IL0024791 <-Find Entered NPDES | Select a NPDES
|Manufacturing! Discharge Type:
|MALDEN STP v/WT Removal
|MALDEN IL G1337 Release Days
107130001033
BIG BUREAU CR
f? Yes f No C Unk. J
|0555G500 ^
01/01/66 09/29/88
Concentration of Concern
Pretreatment Release
Post-treatment Release
Mean Stream Flow
Low Stream Flow
Effluent Flow
3
25 00 %
200.00 days/yr
100.00 ug/L
40.00 kg/site/day
30.00 kg/site/day
178 56 MLD
12.23 MLD
8.00E-02 MLD

Submit
PDM Site-Specific Estimates
Clear Results Table
Print Page
1

COC
Percent of Year COC Exceeded
Number of Days COC Exceeded| Release Days
Pretreat Load
wr
< ug/L)
<*>
(Days) | (Days)
(kg/site/day)
(%)

100.00
36
130 200
40. 00
25.00

Figure 3-41. PDM Site-Specific Results Page (Stand-alone)
PDM employs a simple mass balance approach to calculate stream concentrations. However,
input variables are not constant: streams follow a highly variable seasonal flow pattern and numerous
variables in a manufacturing process can affect the chemical concentration and flow rate of the effluent.
PDM uses probability distributions as inputs and calculates the resulting probability distribution of the
concentration in the stream. PDM currently uses data from various EPA water-related information
systems (See Appendix B). See Appendix C for a description of the statistical framework of PDM.
PDM has two options available for performing analyses, depending on the extent of data
available. The first option addresses site-specific cases. The second option allows for a high-end or
average-case analysis of potential exceedences for an unspecified facility in an industrial category This
option serves as a screening-level analysis to assess the impacts on potentially hundreds of facilities in
an industrial category. The following two sections describe the two options.
3-97
-------
3.4.1 PDM Site-Specific Page
Upon selecting the PDM module, on the Screening-Level Main page (Figure 3-1), the PDM Site-
Specific page will appear (Figure 3-41). Enter a complete or partial National Pollutant Discharge
Elimination System (NPDES) permit number in the NPDES Number field, click on the "Find Entered
NPDES" button, then select a NPDES number from the pull-down list in the "Select a NPDES" field.
(Under the Clean Water Act, discharges of chemicals to surface waters are required to obtain a permit. A
NPDES permit number is a unique nine-character code, beginning with the two-letter state abbreviation.
E-FAST V2.0 only contains NPDES numbers for permitted facilities in the format ILxxxxxxx, where x is
numeric. NPDES numbers for general permits and non-permitted facilities are not included.) Once you
select the NPDES permit number for the facility of interest in the "Select a NPDES" field, the program
will immediately determine if the reach has a USGS gaging station (i.e., measured flow data are available)
or not (i.e., only estimated flow data are available). If the reach has gaging station data available, the
ranked measured daily flow values are used to determine the frequency of exceedence. If only estimated
flow data are available, the program estimates the frequency of exceedence using an integration procedure
presented by Di Toro (1984).
PDM inputs include information entered in the PChem/Fate Inputs screen (Figure 2-1),
information on the discharging facility extracted from the E-FAST V2.0 database, and the Release Days,
Concentration of Concern (COC), and Pretreatment Release information you enter on the PDM Site-
Specific page. Click on the "Submit" button and the results will be added to the table in the lower portion
of the page. PDM estimates the number of days per year and the percentage of the year the COC will be
exceeded. Click on the "Save" button to save the results from this PDM run in your chosen format (MS
Word or WordPerfect); you will be prompted for a name and location for the file. After two or more
releases have been run, the Release Number box on the left hand side of the page can be scrolled to show
all the stored site-specific PDM results.
The following are short descriptions of the fields that appear on the PDM Site-Specific Results
page:
NPDES Number — Under the Clean Water Act, discharges of chemicals to surface waters are
required to obtain a permit. A NPDES permit number is a unique nine-character code, beginning
with the two-letter state abbreviation.
• Release Activity — your description of the release activity (entered on PDM Site-Specific page).
You may leave this field blank.
Facility Name, Location, Reach Number, Reach Name — information on the discharging
facility extracted from the E-FAST V2.0 database when searching for a facility during the data
entry procedure (See Section 3.1.1.1).
Facility on Reach? — indicates whether the facility discharges to the identified reach, discharges
to a tributary stream, or if the discharge point is unknown.
Select a NPDES — NPDES permit number you entered for the facility of interest.
Discharge Type — indicates whether the facility is a direct discharger that discharges treated
wastewater directly to a surface water body or an indirect discharger that discharges wastewater
to a POTW for treatment.
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• Wastewater Treatment (WWT) Removal — percentage of the chemical removed from
wastewater during treatment before discharge to a body of water. This is a chemical-specific
property entered on the PChem/Fate Inputs screen (See Section 2.0).
Release Days — number of days per year that the chemical is discharged, as entered on the
General Release Information page.
Concentration of Concern (COC) — threshold concentration, in micrograms per liter ((.ig/L).
below which adverse effects on aquatic life are expected to be minimal. PDM in E-FAST V2.0
predicts how many days per year the concentration of the chemical in the receiving stream will
exceed the COC.
Pretreatment Release — rate of release of the chemical by the facility to a wastewater treatment
facility (kg/day), as entered on this page.
Post-treatment Release — rate of release of the chemical after treatment by a wastewater
treatment facility (kg/day). The post-treatment release amount is equal to the pretreatment release
reduced by the wastewater treatment removal percentage.
Mean Stream Flow — arithmetic mean flow of the ambient water body receiving the facility's
discharge (MLD), extracted from the E-FAST V2.0 database when searching for a facility during
the data entry procedure (See Section 3.1.1.1).
Low Stream Flow — 7Q10 stream flow (i.e., 7 consecutive days of lowest flow over a 10-year
period) (MLD), extracted from the E-FAST V2.0 database when searching for a facility during
the data entry procedure (See Section 3.1.1.1).
• Effluent Flow — Effluent flow of the discharging facility (MLD), extracted from the E-FAST
V2.0 database when searching for a facility during the data entry procedure (See Section 3.1.1.1).
If the facility selected discharges to an ambient water body with a USGS gaging station, the following
additional information is provided:
• Gaging Station — identification number for the USGS streamflow monitoring site for the
ambient water body receiving the facility's discharge. PDM accesses daily flow values collected
between 1966 and 1991 to calculate the frequency of exceedence.
Period of Record — period for which daily streamflow data are available for the selected gaging
station.
Number of Observations — number of times the daily stream flow was measured during the
period of record.
The lower half of the page presents the following PDM site-specific estimates in a table: the
estimated number of days that the COC will be exceeded in the ambient water body that receives
discharge from the facility; as well as the percent of the year that the COC will be exceeded. These are
described below. In addition to the results, the table includes the following input fields: COC, release
days, pretreatment release load, and the WWT removal rate. These are described above.
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Number of Days COC' Exceeded — estimate of the number of days/year that the COC is
exceeded.
Percent of Year COC Exceeded — the percentage of year that the COC is exceeded. This is
calculated by dividing the exceedence days/year by 365 and multiplying the result by 100.
In addition to these fields, the PDM Site Results page displays a "Print Page" button that may be used to
generate a hard copy of the data on the screen.
3.4.2 PDM SIC Code Results Page
Upon selecting the PDM module on the Screening-Level Main page, the PDM Site-Specific page
will appear. If you are modeling releases by an industrial category, select the PDM SIC Code tab, and the
PDM SIC Code page will appear (Figure 3-42). The SIC codes within E-FAST V2.0 are used to classify
facilities that discharge wastewater to ambient water bodies. The 36 SIC Code categories available for
use with PDM can be viewed and selected from the pull down box labeled "SIC Code Description." To
predict the exceedences of the COC, E-FAST V2.0 performs a high-end or average-case analysis for the
receiving streams of facilities in the selected industrial category.
17* Screening Level Results
PDM Site PDM SIC Code
PDM SIC Code Results
? Help
Release Number:
11123502,2
"3
Release Activity:
SIC Code Description:
SIC Codes:
Dp Hew Release Humbe. | WWT RemoTa|.
Release Days:
Concentration of Concern:
Processing
Paint Formulation
3
Pretreatment Release:
25.00 ^
100 days/year Post-treatment Release:
16.00 kg/site/day
12.00 kg/site/day
100.00 ug/L
<• High-end scenario
f Average case scenario
Clear this Screen Submit Save

PDM SIC Code Estimates ^ Clear Results Table |
Print Page |

COC
Percent of Year COC Exceeded
Number of Days COC Exceeded
Release Days
Pretreat Load
wr

(ug/L)
(%)
(Days)
(Days)
(kg/site/day)
(%)
Analysis
il
H
100.00
12
44
100
16. 00
25 . 00
High

Figure 3-42. PDM SIC Code Results Page (Stand-alone)
PDM inputs include information entered in the PChem/Fate Inputs screen (Figure 2-1); stream
flow information for the SIC Code category extracted from the E-FAST V2.0 database; Release Days,
COC and Pretreatment Release information you enter; and the type of analysis (i.e., high-end or average)
you select on this page. Click on the "Submit" button and the results will be added to the table in the
lower portion of the page. PDM estimates the number of days per year and the percentage of the year the
COC was exceeded. Click on the "Save" button if you want to save the results from this PDM run in
your chosen format (MS Word or WordPerfect); you will be prompted for a name and location for the
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file. After two or more releases have been run, the Release Number box on the left hand side of the page
can be scrolled to show all the stored site-specific PDM results.
The following are short descriptions of the fields that appear on the PDM SIC Code Results page:
• Release Activity — your description of the release activity (entered on the PDM SIC Code
page). You may leave this field blank.
SIC Code Description — text description of the selected industry. The Standard Industrial
Classification (SIC) system was developed by the U.S. Government to provide agencies with a
uniform framework for organizing economic, engineering, and scientific data for a wide range of
economic activities. These activities include agriculture, mining, manufacturing, construction,
utilities, retail trade, and finance. Under the SIC system, every establishment, defined as a single
economic production unit such as a factory, a mill, or a mine, is assigned a four-digit numerical
code.
SIC Codes — 4-digit code or codes assigned to the selected industry.
• Wastewater Treatment (WWT) Removal — percentage of the chemical removed from
wastewater during treatment before discharge to a body of water. This is a chemical-specific
property entered on the PChem/Fate Inputs screen (See Section 2.0).
Release Days — number of days per year that the chemical is discharged, as entered on this page.
Concentration of Concern (COC) — threshold concentration (in (ig/L). below which adverse
effects on aquatic life are expected to be minimal. PDM in E-FAST V2.0 predicts how many
days per year the concentration of the chemical in the receiving stream will exceed the COC.
Pretreatment Release — rate of release of the chemical by the facility to a wastewater treatment
facility (kg/day), as entered on this page.
Post-treatment Release — rate of release of the chemical after treatment by a wastewater
treatment facility (kg/day). The post-treatment release amount is equal to the pretreatment release
reduced by the wastewater treatment removal percentage.
High-end Scenario — averaged probability of exceedence of the 10 percent of the facilities of
the selected industrial category that have the highest probability of exceedence for the COC and
the loading rate specified by you for worst-case scenarios.
Average Case Scenario — mean exceedence probability for all facilities within an industrial
category.
The lower half of the page presents the following PDM SIC Code estimates in a table: the
estimated number of days that the COC will be exceeded in the ambient water body that receives
discharge from the facility; as well as the percent of the year that the COC will be exceeded. These are
described below. In addition to the results, the table includes the following input fields: COC, release
days, pretreatment release load, WWT removal rate and the type of scenario (i.e., high-end or average
case) selected. These are described above.
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Number of Days COC Exceeded — estimate of the number of days/year that the COC is
exceeded.
Percent of Year COC Exceeded — the percentage of year that the COC is exceeded. This is
calculated by dividing the exceedence days/year by 365 and multiplying the result by 100.
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4.0 REFERENCES
Chinn, K.S.K. 1981. A Simple Model for Predicting Chemical Agent Evaporation, Technical Report, U.S.
Department of Defense, Defense Technical Information Center, Cameron Station, Alexandria,
VA.
Di Toro, D. M. 1984. "Probability Model of Stream Quality Due to Runoff. ASCE." Journal of
Environmental Engineering. 110(3):607-628.
Evans, W.C. 1994. "Development of Continuous-Application Source Terms and Analytical Solutions for
One- and Two-Compartment Systems," in Characterizing Sources of Indoor Air Pollution and
Related Sink Effects, ASTM STP 1287, American Society for Testing and Materials, pp 279-293.
General Sciences Corporation (GSC). 1987. Groundwater Scenarios for Screening Level Assessments of
Compounds Released to Land. Report prepared for U.S. EPA, Office of Toxic Substances. EPA
Contract No. 68-02-3970.
Mathews, J.H. 1992. Numerical Methods for Mathematics, Science and Engineering, Second Edition.
Prentice Hall, Englewood Cliffs, NJ.
Phillips, L.J.; R.J. Fares; L.G. Schweer. 1993. "Distributions of Total Skin Surface Area to Body Weight
Ratios for Use in Dermal Exposure Assessments." Journal of Exposure Analyses and
Environmental Epidemiology. 3(3):331-338.
Sandberg, M. 1984. "The Multi-Chamber Theory Reconsidered from the Viewpoint of Air Quality
Studies." Building and Environment 13:21-28.
Turner, D. 1994. Workbook of Atmospheric Dispersion Estimates: An Introduction to Dispersion
Modeling. 2d ed. Boca Raton, FL: CRC Press, Inc.
U.S. Bureau of the Census. 2004-2005. Statistical Abstract of the United States: 2004-2005. 2003 U.S.
Resident Population. U.S. Bureau of the Census URL: (http://www.census.gov).
U.S. EPA. 1985a. Memorandum from Elizabeth Bryan to PMN Assessors, Office of Pollution Prevention
and Toxic Substances. January 16, 1985.
U.S. EPA. 1985b. Development of Statistical Distributions or Ranges of Factors Used in Exposure
Assessments. Office of Health and Environmental Assessment. EPA/600/8-85/010.
U.S. EPA. 1987a. Memorandum from Annette Nold to Pat Kennedy, Office of Pollution Prevention and
Toxics. January 29, 1987.
U.S. EPA. 1987b. Guideline on Air Quality Models (Revised) Office of Air Quality Planning and
Standards, Research Triangle Park, NC. EPA/450/2-78/027R.
U.S. EPA. 1987c. Methods for Assessing Exposure to Chemical Substances: Volume 7, Methods for
Assessing Consumer Exposure to Chemical Substances. Office of Toxic Substances. EPA/560/5-
85/007.
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U.S. EPA. 1991. Technical Support Document for Water Quality-Based Toxics Control. Office of Water.
EPA/505/2-90/001.
U.S. EPA. 1992a. A Tiered Modeling Approach for Assessing the Risks Due to Sources of Hazardous Air
Pollutants. Research Triangle Park, NC: Office of Air Quality Planning and Standards,
EPA/450/4-92/001. March 1992.
U.S. EPA. 1992b. Screening Procedures for Estimating the Air Quality Impact of Stationary Sources,
Revised. Research Triangle Park, NC: Office of Air Quality Planning and Standards, EPA/454/R-
92/019. October 1992.
U.S. EPA. 1992c. A Laboratory Method to Determine the Retention of Liquids on the Surface of Hands.
Office of Pollution Prevention and Toxics. EPA 747-R-92-003.
U.S. EPA. 1992d. Dermal Exposure Assessment: Principles and Applications. Office of Research and
Development. EPA/600/8-91/01 IB.
U.S. EPA. 1995a. SCREEN3 User's Guide. Research Triangle Park, NC: Office of Air Quality Planning
and Standards, EPA/454/B-95/004. September 1995.
U.S. EPA, 1995b. User's Guide for the Industrial Source Complex (ISC3) Dispersion Models Volume II -
Description of Model Algorithms. Office of Air Quality Planning and Standards. EPA/454/B-
95/003b.
U.S. EPA. 1996. Needs Survey. Washington, DC: Office of Wastewater Enforcement and Compliance.
U.S. EPA. 1997. Exposure Factors Handbook. Office of Research and Development. EPA/600/P-95/002F
U.S. EPA. 2002. Memorandum from Lynn Delpire to Conrad Flessner, Office of Pollution Prevention and
Toxics. May 2002.
U.S. EPA. 2004. Endangered Species Protection Program (ESPP) Databases (February 2004 release).
Office of Pesticide Programs.
U.S. OMB. 1998. North American Industry Classification System, United States, 1997. Executive Office
of the President, Office of Management and Budget.
Versar, Inc. 1986. Standard Scenarios for Estimating Exposure to Chemical Substances During
Use of Consumer Products, Volumes land 2. Prepared for U.S. EPA, Office of Toxic Substances.
EPA Contract No. 68-02-3968.
Versar, Inc., 1989. Data base of PFT Ventilation measurements: Description and user's manual.
Washington, DC: U.S. Environmental Protection Agency, Office of Toxic Substances. Contract
No. 68-2-4254.
Versar, Inc. 1992. Upgrade of Flow Statistics Used to Estimate Surface Water Chemical Concentration
for Aquatic and Human Exposure Assessment. Prepared for U.S. EPA, Office of Pollution
Prevention and Toxics. EPA Contract No. 68-D9-0166, Task No. 3-48.
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Versar, Inc. 2003. Source Ranking Database. Prepared for U.S. EPA, Office of Pollution Prevention and
Toxics. EPA Contract No. 68-W6-0023.
Westat, Inc. 1987a. National Usage Survey of Household Cleaning Products. Prepared for U.S. EPA,
Office of Toxic Substances. EPA Contract No. 68-02-4243.
Westat, Inc. 1987b. Household Solvent Products: A National Usage Survey. Prepared for U.S. EPA,
Office of Toxic Substances. EPA Contract No. 68-02-4243.
Wilkes, C.; M. Koontz; M. Ryan; C. Cinalli. 1996. Estimation of Emission Profiles for Interior Latex
Paints. Paper from proceedings of Indoor Air '96.
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Appendix A
Definitions for Physical-Chemical/Fate Properties
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DEFINITIONS FOR PHYSICAL-CHEMICAL/FATE PROPERTIES
The following are definitions for physical-chemical constants used in E-FAST V2.0. The
particular physical constants used depend on which model is selected. The physical constants are defined
below:
Adsorption to wastewater treatment sludge — expressed as a percentage, the amount of the chemical
of concern that accumulates in wastewater treatment sludge divided by the total amount of the chemical in
the untreated wastewater. The percentage adsorbed depends on the physical-chemical properties of the
chemical, the biodegradability of the chemical, and the unit-treatment processes at the treatment plant.
You should assume that industrial discharges to surface water are treated in a wastewater treatment
facility before release to a body of water. The percent adsorbed cannot be greater than the wastewater
treatment removal.
Bioconcentration factor (BCF) — the ratio (mg/kg in fish, divided by mg/L in water, = L/kg) of a
chemical's concentration in the tissue of an aquatic organism to its concentration in the ambient water.
The BCF is used to estimate the potential equilibrium concentration of a chemical in fish tissue resulting
from the predicted concentration in surface water; the BCF factor times the chemical's surface water
concentration equals the chemical concentration in fish tissue. Potential human exposure via fish
ingestion is based on this estimated fish tissue concentration.
BCF factors can be for whole fish, fish muscle, specific fish organs, etc.. The appropriate BCF factor to
use depends on the endpoint to be determined, e.g., since people generally eat fish fillets rather than
whole fish, fish muscle BCF is more appropriate for potential human dose estimates of fish than the
whole fish BCF. However, if only whole fish BCF values are available, those values can still be used to
calculate the human potential dose rate to the chemical from ingestion of fish, as long as it is understood
that the BCF for the fish fillet may be different—it is usually expected to be lower than the whole fish
BCF, since the latter includes organs where greater bioconcentration usually occurs. This means the
estimated dose would be higher than the actual dose; however, this is an acceptable approach for a
screening-level analysis that estimates high-end to bounding exposure values. How different may the
whole fish BCF be from the fish fillet BCF? In EPA's EPI Suite BCFW1Nmodel, BCFs for whole fish
and fish fillet are very close, probably not significantly different (Personal communication from Dr.
Vince Nabholz, U.S. EPA to Conrad Flessner, U.S. EPA, March 2004).
Another consideration in the use of the BCF factor is whether it reflects the potential for metabolism.
Measured BCF values do, of course, but estimation methods for BCF may or may not. For example, the
Structure Activity Relationships the EPI Suite BCFWIN model uses to estimate BCFs are based on
measured fish BCFs for chemicals with nil to average metabolism; chemicals with rapid metabolism, e.g.,
benzo(a)pyrene, were not included in this BCF model, so it cannot be used to estimate BCFs for
chemicals that are analogs to those with rapid metabolism.
Chemical Abstracts Service (CAS) number — the unique number assigned to a substance when it
enters the CAS Registry database. Numbers are assigned in sequential order to unique, new substances
identified by CAS scientists for inclusion in the database. Each CAS Registry number is a unique
numeric identifier, represents only one substance, has no chemical significance, and is a link to a wealth
of information about a specific chemical substance.
A-2
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Chemical name — the name of the chemical being modeled. This parameter can be different from the
product name.
Consumer product weight fraction (central tendency) — for example, the median or the ratio of the
50th percentile weight of the chemical being analyzed found in the product to the weight of the product.
This parameter is unitless.
Consumer product weight fraction (high-end) — for example the ratio of the 90th percentile weight of
the chemical being analyzed found in the product to the weight of the product. This parameter is unitless.
Drinking water treatment removal — the removal percentage that is based on the physical-chemical
characteristics of the chemical and the expected efficiency of unit treatment processes at the drinking
water treatment facility.
Fugitive air emissions removal — the removal percentage that is based on the physical-chemical
characteristics of the chemical and the expected efficiency of processes used to reduce fugitive emissions
from the facility.
Henry's law constant — the ratio of a chemical's vapor pressure to its solubility. Henry's law constant
gives a relative measure of a compound from water by measuring the extent to which a compound will
partition between water and the air.
Log organic carbon/water partition coefficient (log Koc) — chemical-specific adsorption parameter
for organic substances that is largely independent of the properties of soil or sediment and can be used as
a relative indicator of adsorption to such media. The larger the Koc, the more likely that the chemical will
adsorb to solid material. Koc is highly inversely correlated with solubility, well correlated with
octanol-water partition coefficient, and fairly well correlated with BCF.
Log octanol/water partition coefficient (log Kow) — the ratio of the chemical concentration in octanol
divided by the concentration in water. Kow indicates whether a chemical will be found predominantly in
water or in the fatty tissue of an animal.
Migration Descriptor — an expression of the chemical's tendency to migrate from the waste being
disposed of in the landfill to surrounding soil, and eventually to groundwater. The migration descriptors
as used by E-FAST V2.0 are negligible, negligible to slow, slow, moderate, and rapid; a rating of
"negligible" indicates that the chemical does not reach groundwater. The migration descriptor should be
chosen selected on the basis of physical-chemical parameters such as the log of the organic carbon/water
partition coefficient (log Koc), the log of the n-octanol/water partition coefficient (log Kow), the expected
leachability of the chemical from the type of waste being disposed, and the reactivity of the chemical,
which includes transformation processes such as biodegradation and hydrolysis (as applicable).
Molecular weight — the sum of the atomic weights of the atoms that constitute the chemical being
analyzed. The units for this parameter are grams per mole (g/mol).
Permeability coefficient (Kp) — flux value, normalized for concentration, that represents the rate at
which the chemical penetrates the skin (cm/hr). The permeability coefficient for a chemical of concern
can be calculated from the chemical's octanol/water partition coefficient Kow (unitless) and the molecular
weight (g/mol).
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Stack air emissions removal — the removal percentage that is based on the physical-chemical
characteristics of the chemical and the expected efficiency of treatment unit processes that are used to
reduce point source emissions from the facility.
Vapor pressure (scenario-dependent) — the pressure exerted by a vapor in equilibrium with its solid or
liquid phase. This parameter is only required for inhalation scenarios. There are various units for this
parameter. Vapor pressure can be entered in E-FAST V2.0 in units of Atmospheres, Torr (millimeters of
Mercury), Millibars, or Pascals.
Wastewater treatment removal — the removal percentages at a wastewater treatment plant. The
percentage removed depends on the physical-chemical properties of the chemical, the biodegradability of
the chemical, and the unit-treatment processes at the treatment plant. Removal of some or possibly all of
the chemical substance usually occurs during wastewater treatment. You should assume that industrial
discharges to surface water are treated in a wastewater treatment facility before release to a body of water.
A-4
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Appendix B
Exposure and Fate Assessment Screening Tool, Version 2.0 (E-FAST2)
Surface Water Discharge Information Organization and Sources
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TABLE OF CONTENTS
Page No.
PREAMBLE iii
GLOSSARY v
1.0 INTRODUCTION 1-2
2.0 GENERAL POPULATION AND ECOLOGICAL EXPOSURE (GPE)
INDUSTRIAL RELEASES PATHWAY 2-2
2.1 Background 2-2
2.1.1 Site-Specific Option 2-4
2.1.2 SIC Code Option 2-4
2.1.3 Probabilistic Dilution Model (PDM) 2-5
2.1.4 Revisions to GPE Model 2-5
2.2 Data Sources in GPE 2-7
2.2.1 Facility Discharge Information 2-7
2.2.2 Receiving Stream Information 2-12
2.2.3 Stream Dilution Factor Program (SDFP) 2-14
2.2.4 Endangered Species Database 2-14
2.3 Hierarchy Used in Selection of Data Elements 2-15
3.0 DOWN-THE-DRAIN PATHWAY 3-2
3.1 Background 3-2
3.1.1 Revisions to Down-the-Drain 3-3
3.2 Data Sources in Down-The-Drain 3-4
3.2.1 E-FAST2 Main Facility File 3-4
3.2.2 Stream Dilution Factor Program 3-5
3.2.3 Basin Coefficient File 3-6
4.0 PROBABILISTIC DILUTION MODEL (PDM) PATHWAY 4-2
4.1 Background 4-2
4.1.1 Site-Specific Option 4-2
4.1.2 SIC Code Option 4-3
4.1.3 Revisions to PDM 4-4
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TABLE OF CONTENTS (cont'd)
Page No.
4.2 Data Sources in PDM 4-5
4.2.1 E-FAST2 Main Facility File 4-5
4.2.2 STORET Daily Flow Statistical File 4-6
4.2.3 Basin Coefficient File 4-7
5.0 REFERENCES 5-1
Tables
Table 2-1 Data Elements in E-FAST2 Main Facility File of Direct Dischargers 2-16
Figures
Figure 1-1 Exposure and Fate Assessment Screening Tool, Version 2.0 (E-FAST2)
Pathways 1-1
Figure 2-1 Module 1 of Exposure and Fate Assessment Screening Tool, Version 2.0
(E-FAST2) - General Population and Ecological Exposure (GPE) from Industrial
Releases Pathway 2-1
Figure 3-1 Module 2 of Exposure and Fate Assessment Screening Tool, Version 2.0
(E-FAST2) - Down-the-Drain Pathway 3-1
Figure 4-1 Module 3 of Exposure and Fate Assessment Screening Tool, Version 2.0
(E-FAST2) - Probabilistic Dilution Model (PDM) Pathway 4-1
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PREAMBLE
The Exposure and Fate Assessment Screening Tool (E-FAST) was developed by the Office of
Pollution Prevention and Toxics' (OPPT) Exposure Assessment Branch for use as a screening
tool to assess potential exposure from chemical discharges to air (stack and fugitive releases),
surface water, and landfills, as well as to assess inhalation and dermal exposures to chemicals
in consumer products. E-FAST is composed of four separate exposure assessment modules: (1)
the General Population and Ecological Exposure (GPE) from Industrial Releases Pathway; (2)
the Down-the-Drain Pathway; (3) the Consumer Exposure Pathway; and (4) the Probabilistic
Dilution Model (PDM) Pathway. Three of these four pathways (GPE, Down-the-Drain, and
PDM) address discharges to surface water as discussed in more detail in the following sections
of this report.
The surface water discharge information for the three pathways has been revised in E-FAST
Version 2.0 (E-FAST2) to utilize the most current readily available and accurate facility
and receiving stream information that would be consistent with data throughout the three
pathways. These data are contained within the E-FAST2 Main Facility File. Separate files, as in
the original E-FAST, will no longer be used for each module, and when the Main Facility File is
updated, all of the surface water modules will be automatically updated. The Main Facility File
was created by extracting various information from six water-related information systems, as
well as supplemental information. While information for indirect dischargers was included in the
original E-FAST model, it is not included in the E-FAST2 Main Facility File due to limitations.
The original source of data for indirect dischargers has become outdated and limitations in
obtaining and using data from alternate sources precludes their use at this time. More
information on the data sources used to create the E-FAST2 Main Facility File is available in
Section 2.2 of this report.
Additional data files are used in the various pathways ofE-FAST2 in conjunction with the Main
Facility File. These include the files of statistical stream data used in the Down-the-Drain and
PDM Pathways (also included in the original E-FAST). As a new feature, an additional data file
of endangered species is now included in the E-FAST2 GPE Pathway. The user may now search
for a list of endangered species in the vicinity of a facility's discharge to surface waters.
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Analyses performed using the Stream Dilution Factor Program (SDFP) in the GPE and Down-
the-Drain Pathways have also been revised in E-FAST2. SDFP now only includes data for
direct dischargers (including POTWs) as contained within the Main Facility File. While the
same methodology employed in the original SDFP is used, the retrieval of receiving stream data,
calculation of dilution factors, and ranking of the flow data and dilutions are now all conducted
within the GPE and Down-the-Drain Pathways in E-FAST2. This ensures that future updates
will be made efficiently and cost-effectively. Additional changes to SDFP include the loss of
four of the original 40 industries due to the use of data for only direct dischargers that are
included in the Main Facility File and a change in the "POTWs-Industrialized" category. This
category was originally based on POTWs that received discharges from indirect facilities in
select industrial categories. In E-FAST2, these POTWs are selected based on their pretreatment
designation in the Permit Compliance System (PCS).
Revisions to the PDM Pathway (including the probability calculations in the GPE and Down-
the-Drain Pathways) in E-FAST2 have been extensive. PDMnow utilizes an approach that is
more transparent and flexible for the average model user. The approach uses the most current
readily available data from the E-FAST2 Main Facility File; the same data used in the other
pathways (GPE and Down-the-Drain) ofE-FAST2. The probability of exceedence calculations
are now performed within PDM rather than using a matrix probability/ratio/interpolation
method. The original E-FASTPDM required statistical "matrix files " that were created by
performing thousands of stochastic calculations and storing the results. The files became out-of-
date following any update of data and required interpolation before they were used. The current
approach in the E-FAST2 PDM makes the use of "look-up" matrix files obsolete and ensures
that future updates of PDM can be made efficiently and cost-effectively.
All of the revisions that have been incorporated into E-FAST2, along with recommendedfuture
revisions, are discussed in more detail in the following sections of this report (Sections 2.1.4 -
GPE, Sections 3.1.1 - Down-the-Drain, and Sections 4.1.3 - PDM).
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GLOSSARY
305^ Assessments - Water quality assessment reports prepared by States, and submitted to
EPA every two years. EPA summarizes these reports, as required under Section 305(b) of the
Clean Water Act of 1972, into the National Water Quality Inventory Report to Congress, or the
305(b) report.
303^ Lists - Lists of stream segments that do not meet water quality standards. Section 303(d)
of the federal Clean Water Act requires each State to maintain these lists.
10th Percentile Receiving Stream Flows - The stream flow value that is greater than one-tenth and
less than nine-tenths of the stream flow distribution under consideration.
50th Percentile Receiving Stream Flows - The stream flow value that is the median for the stream
flow distribution under consideration.
CEM - Consumer Exposure Model
COC - concentration of concern - The concentration of a chemical in a water body (e.g.,
receiving stream, lake, etc.), above which there is a high risk to the aquatic life in the stream.
CSO - Combined Sewer Overflow
CWNS - Clean Water Needs Survey
Dilution Factor - The number calculated by dividing the receiving stream flow by the facility
effluent flow.
Direct Discharger (Direcf) - A municipal or industrial facility which introduces pollution through
a defined conveyance or system; a point source. Direct dischargers include industrial facilities
that discharge wastewater directly into a surface body of water (e.g., lake, river, stream).
EDSS - Effluent Data Statistics System
E-FAST2 - Exposure and Fate Assessment Screening Tool, Version 2.0
ESPP - Endangered Species Protection Program
GIS - Geographic Information System
GPE - General Population and Ecological Exposure
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GLOSSARY (Cont'd)
Hvdrologic Unit Maps - Maps developed by USGS that provide a classification of the United
States based on watersheds. The United States is divided and sub-divided into successively
smaller hydrologic units which are four levels: regions, sub-regions, accounting units, and
cataloging units.
IFD - Industrial Facilities Discharge File
Indirect Discharger (Indirect^) - A municipal or industrial facility which introduces pollutants
from a non-domestic source into a publicly-owned waste treatment system. Indirect dischargers
can be commercial or industrial facilities that discharge wastes into the local sewers.
Mixing Zone - An area where an effluent discharge undergoes initial dilution and is extended to
cover the secondary mixing in the ambient waterbody.
NHD - National Hydrography Dataset
NO A A - National Oceanic and Atmospheric Administration
NPDES - National Pollutant Discharge Elimination System (NPDES) is an EPA permit program
that regulates discharges from point sources into waters of the U.S. Facilities are issued NPDES
permits regulating their discharge as required by the Clean Water Act.
OW - U.S. EPA, Office of Water
PCS - Permit Compliance System
PPM - Probabilistic Dilution Model
PMN - Premanufacture Notification; refers to a stage in the assessment process applied to new
chemical products under the Toxic Substances Control Act (TSCA).
POTW - Publicly-Owned Treatment Works; a wastewater treatment facility.
Pretreatment - Processes used to reduce, eliminate, or alter pollutants from nonresidential
sources before they are discharged into POTWs.
REACH - Stream segment that is part of the U.S. surface water drainage system.
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GLOSSARY (Cont'd)
Receiving Stream Flows:
7Q10 - lowest consecutive 7-day average flow during any 10-year period
1Q10 - lowest 1-day flow during any 10-year period
30Q5 - lowest consecutive 30-day flow during any 5-year period
Harmonic Mean Flow - inverse mean of reciprocal daily arithmetic mean flow values
SDFP - Stream Dilution Factor Program
SDWIS - Safe Drinking Water Information System
SIC Code - Standard Industrial Classification (SIC) System; 4-digit numerical code established
by the Office of Management and Budget used to classify the economic activities of most of the
industries and kinds of business establishments in the United States
SSO - Sanitary Sewer Overflow
STORET (short for STOrage and RETrieval) - EPA's largest computerized environmental data
system that serves as a repository for water quality, chemical, biological, and physical data used
by state environmental agencies, EPA and other federal agencies, universities, private citizens,
tribes, and volunteer groups.
USGS - United States Geological Survey
WEG - File of estimated streamflows prepared for EPA's Office of Water, Monitoring Branch
by W. E. Gates and Associates, Inc. in 1982.
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Module 1
General Population and Ecological Exposure (GPE)
from Industrial Releases Pathway
Module 2
Down-the-Drain
Pathway
Module 3
Module 4
Surface Water Releases
Site-
Specific
=n
Indirects Directs
SIC Code
(SDFP)
i
Drinking Water Exposure
Fish Ingestion Exposure
Aquatic Exposure
Consumer Exposure Pathway
Probabilistic Dilution Model (PDM)
Pathway
Aquatic Environment
Exposure / Risk
I All Facilities Statistical Calculation!
Identify

POTW

Main Facility File
Main Facility File
All POTWs Statistical
Calculation (SDFP)

All POTWs Probability
Statistical Calculation
i

i
Main Facility File

Main Facility File
| Site-Specific | | SIC Code |
Site-Specific Probability
Statistical Calculation
PCS
1. Facilities / POTWs (F/P)
2. Effluent Flow(EF)
3. Receiving Stream (RS) / Reach
Extract: F/P and RS, Apr. 2002; EF, 19
Task 73b
1. Facilities
2. Receiving Stream / Reach
3. Dilution Factors
Extract: Nov. 1998
IFDb
1. Receiving Stream / Reach
2. Effluent Flow
Extract: Nov. 1998
GAGEb
1. Receiving Stream WEG Flow
Extract: Nov. 1998
REACH
1. Surface Water Features
2. Open Water Reach Numbers
Extract: Nov. 1998
1996 NEEDS
1. Total POTW Flow
2. Domestic POTW Flow
3. Population Served
Extract: Nov. 1998/July 2004
Supplemental
Receiving Stream / Reach for 315
POTWs and facilities from new
chemical reviews
Extract: Apr. 2002
Endangered Species'3
1.Name
2. Location
3. Action/Occurrence
Extract: 2004
estimated
flows

Main Facility File

measured
estimated

flows
flows
All Facilities Probability
Statistical Calculation
i ~
Main Facility File
estim ated
flows
Basin Coefficient
Statistical Filed
Extract: 1991
USGS Stations
STORET Daily Flow
Statistical Filed
Basin Coefficient
Statistical Filed
Basin Coefficient
Statistical Filed
m
Information Source
Footnotes:
a. See Probabilistic Dilution Model Pathway
b. No longer supported or maintained by EPA
c. Effluent flows estimated from PCS using the Effluent Data Statistics System (EDSS)
d. Used in conjunction with Main Facility File
Other Notes:
1. IFD, GAGE, and REACH were downloaded from EPA's mainframe in 1999/2000 to
EAB's Oracle system and to SAS datasets maintained by Versar.
2. Extract date may differ from date of Source's last update. See text for details.
Figure 1-1
Exposure and Fate Assessment Screening Tool, Version 2.0 (E-FAST2) Pathways
(Surface Water Discharge Information Organization and Sources)
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1.0 INTRODUCTION
The Exposure and Fate Assessment Screening Tool, Version 2.0 (E-FAST2) is a
screening-level computer model that allows users to estimate chemical concentrations in
water to which aquatic life may be exposed, as well as generate human inhalation, drinking
water ingestion, and fish ingestion exposures resulting from chemical releases to air, water, and
land. E-FAST2 also may be used to assess inhalation and dermal exposures to chemicals that
may result from the use of certain types of consumer products. The exposed populations
assessed by the model are either some segment of the general population or consumers. Worker
exposures are not assessed in this model.
E-FAST2 is composed of four separate exposure assessment modules:
General Population and Ecological Exposure (GPE) from Industrial Releases
Pathway - addresses human and aquatic ecological exposures resulting from facility
releases to air, water, and land.
Down-the-Drain Pathway - addresses human and aquatic ecological exposures to
chemical releases in household wastewater.
Consumer Exposure Pathway - addresses various consumer exposure pathways (i.e.,
dermal and inhalation) using the Consumer Exposure Model (CEM). The model
calculates exposure resulting from consumer use. In addition to eight generic scenarios,
CEM also allows for user-defined scenario inputs.
Probabilistic Dilution Model (PDM) Pathway - addresses aquatic ecological
exposures. PDM is used by the GPE and Down-the-Drain modules to calculate
concentrations and to predict the number of days per year a chemical's concentration of
concern (COC) in an ambient water body will be exceeded by the discharge from a
facility. This module allows the user to run the model independently of the release
scenarios that are used in the GPE and the Down-the-Drain modules.
Three of the four pathways (GPE, Down-the-Drain, and PDM) address discharges to
surface waters. Figure 1-1 presents an overview of the surface water discharge information
organization and sources for the three pathways. The primary source of facility and basic
receiving stream information in all pathways of E-FAST2, the Main Facility File, has been
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highlighted. The pathways are discussed in more detail in the following sections (Section 2.0 -
GPE, Section 3.0 - Down-the-Drain, and Section 4.0 - PDM). Included in each section is
information on the development and use of the pathway (background), including changes from
the original E-FAST, data elements and sources used in the pathway. Only water releases are
discussed.
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Module 1
General Population and Ecological Exposure (GPE)
from Industrial Releases Pathway
Surface Water Releases

Site-Specific

Indirects
Directs
I
I
SIC Code (SDFP)
PDM£
Identify POTW
All Facilities Statistical Calculation
Main Facility File
PCS
1. Facilities / POTWs (F/P)
2. Effluent Flow (EF)
3. Receiving Stream (RS) / Reach
Extract: F/P and RS, Apr. 2002; EF, 1996c
Task 73b
1. Facilities
2. Receiving Stream / Reach
3. Dilution Factors
Extract: Nov. 1998
IFDb
1. Receiving Stream / Reach
2. Effluent Flow
Extract: Nov. 1998
GAGEb
1. Receiving Stream WEG Flow
Extract: Nov. 1998
REACH
1. Surface Water Features
2. Open Water Reach Numbers
Extract: Nov. 1998
1996 NEEDS
1. Total POTW Flow
2. Domestic POTW Flow
3. Population Served
Extract: Nov. 1998/July 2004
Supplemental
Receiving Stream / Reach for 315 POTWs
and facilities from new chemical reviews
Extract: Apr. 2002
Main Facility File
Endangered Speciesd
1. Name
2. Location
3. Action/Occurrence
Extract: 2004
Calculate percentile flows
for Industrial Categories
Identification of
Industrialized POTWs
from pretreatment code
© Information Source
Footnotes:
a. See Probabilistic Dilution Model Pathway
b. No longer supported or maintained by EPA
c. Effluent flows estimated from PCS using the Effluent
Data Statistics System (EDSS)
d. Used in conjunction with Main Facility File
Other Notes:
1. IFD, GAGE, and REACH were downloaded from
EPA's mainframe in 1999/2000 to EAB's Oracle
system and to SAS datasets maintained by Versar.
2. Extract date may differ from date of Source's last
update. See text for details.
Figure 2-1
Exposure and Fate Assessment Screening Tool, Version 2.0 (E-FAST2)
General Population and Ecological Exposure (GPE) from Industrial Releases Pathway
(Surface Water Discharge Information Organization and Sources)
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2.0 GENERAL POPULATION AND ECOLOGICAL EXPOSURE (GPE)
INDUSTRIAL RELEASES PATHWAY
2.1 Background
The GPE Pathway is a screening level model. Based on information contained in an
internal database and user inputs, GPE generates estimates of chemical concentrations in surface
waters to which aquatic life may be exposed and estimates of human inhalation and drinking
water exposures (potential dose rates) resulting from chemical releases to water, air and land.
Developed as part of the original E-FAST in 1999, the GPE Model is used to support the U.S.
Environmental Protection Agency (EPA) assessments of the potential exposures to new
chemicals which are submitted to EPA under Section 5 of the Toxic Substances Control Act
(TSCA).
Wastewaters generated by manufacturing, processing, and industrial and commercial use
are typically sent to on-site treatment or are sent to publicly-owned treatment works (POTWs)
prior to release to surface waters. The receiving water will dilute the discharge from the facility
or the POTW, and an instream concentration of the chemical can be estimated using stream flow
information in a simplified dilution analysis that does not account for fate processes other than
complete and immediate mixing.
The GPE Model estimates surface water concentrations in rivers and streams under four
receiving stream flow conditions (1Q10 low flow, 7Q10 low flow, 30Q5 low flow, and harmonic
mean flow) as recommended in the Technical Support Document for Water Quality-based Toxics
Control (U.S. EPA, 1991). Harmonic mean flows are used to generate estimates of chronic
human exposure via drinking water and fish ingestion. EPA defines the harmonic mean flow as
the inverse mean of reciprocal daily arithmetic mean flow values. EPA recommends using the
long-term harmonic mean to assess potential human health impacts because it provides a more
conservative estimate than the arithmetic mean flow. The 30Q5 flows (lowest consecutive 30-
day flow during any five-year period) are used to generate estimates of acute human exposure
via drinking water. To estimate potential acute and chronic aquatic life impacts, the model uses
1Q10 and 7Q10 flows, which are the lowest 1-day and the lowest consecutive 7-day average
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flows during any 10-year period, respectively. The stream data used are estimated flows at the
downstream end of specific stream segments (reaches), and are presumed to include the
discharge flow from any facility on that reach.
In some cases, the mean effluent flow from a facility is larger than the estimated 7Q10
flow of the receiving reach. This may be a case where the facility effluent flow is intermittent,
and the reach 7Q10 flow represents the stream flow at the time of zero or low effluent flow. For
E-FAST2, OPPT has used the assumption that the value to be used to represent the stream flow
in the vicinity of the facility should be the greater of the following two flow values: (1) the
effluent flow for the facility of interest or (2) the stream flow.
If the effluent flow is greater than the stream flow, the effluent flow is used to represent
the stream flow because the effluent flow represents the least amount of flow available.
For cases where the stream flow is greater than the effluent flow, there is a possibility
that the effluent is included in the stream flow. If the stream flow includes the effluent, dividing
by the stream flow yields the most accurate estimate of the in-stream chemical concentration. If
the stream flow does not include the effluent, then the stream flow represents the least amount of
water available for dilution, and therefore, the most conservative chemical concentration value.
(Note: As stated in the E-FAST2 Introduction, the model is intended to be conservative.)
Because stream flows are not available for hydrologically complex waters such as bays,
estuaries, and oceans, the model uses site-specific critical dilution factors (DFs) to estimate
chemical concentrations for facilities discharging to these types of waterbodies. A survey of
States and Regions, conducted by Versar for OPPT, Mixing Zone Dilution Factors for New
Chemical Exposure Assessments (Versar, 1992a) and Development of Mixing Zone Dilution
Factors (Versar, 1997), provide the site-specific critical DFs.
As seen in Figure 2-1, the GPE Model has two options available for performing analyses,
depending on the extent of data available. The first option addresses site-specific cases. The
second option addresses generic releases from unspecified facilities in an industrial category or
specific SIC code(s). Within each option, a user may select the PDM to predict the number of
days per year a chemical's COC(s) would be exceeded in a receiving body of water (stream,
river, lake, etc.) due to the discharge from a facility. The following sections briefly describe the
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two options and PDM, as well as recent revisions to the GPE Model. PDM is discussed in
greater detail in Section 4.0.
2.1.1 Site-Specific Option
The Site-Specific Option is selected when the identity of the discharging facility is
known. The GPE Model searches for a facility in the E-FAST2 Main Facility File based on the
National Pollutant Discharge Elimination System (NPDES) number, facility name, SIC Code, or
reach number. After finding the facility of interest and entering the number of release days and
the loading (i.e. mass of chemical discharged per day), the model determines the surface water
concentrations under the four flow conditions. Harmonic mean, 30Q5, and 1Q10 flows are
calculated from estimated 7Q10 and arithmetic mean flows (Versar, 1992b). The E-FAST2 Main
Facility File contains records for over 27,000 direct discharging facilities.
To perform an analysis for an indirect facility, the NPDES number (or some other
identifying information such as the name and/or location) of the POTW that receives the
discharge needs to be known. The POTW information is then used by the GPE model, as if the
facility is discharging to the receiving stream of the POTW. If the removal rate for the chemical
at the POTW is known, this can also be taken into account. Otherwise a worst-case scenario of
zero percent removal can be assumed.
2.1.2 SIC Code Option
The SIC Code Option is selected when the exact location of a chemical loading is
unknown, but, the representative industry or SIC code(s) is known. The option uses the same
facility information and calculations as the site-specific option, except the calculations are
performed using the 10th and 50th percentile receiving stream flows for representative dischargers
in the selected SIC code(s) using the Stream Dilution Factor Program (SDFP). SDFP is
currently used to (1) retrieve receiving stream flow data from the E-FAST2 Main Facility File
for facilities in a particular industry or SIC code(s); (2) calculate dilution factors for each facility
(receiving stream flow divided by effluent flow); and (3) rank the flow data and dilution factors,
and report the results in terms of percentiles.
The majority of facilities in the E-FAST2 Main Facility File are POTWs. The facilities
that comprise the category of "POTWs - Industrialized" are those POTWs that have a
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pretreatment code in PCS that identifies the POTW as having a pretreatment program to treat
pollutants in wastewater from industrial (non-domestic) users. All 35 of the other selected
industrial categories in E-FAST2 are based on a facility's SIC code.
2.1.3 Probabilistic Dilution Model (PDM)
PDM is available within both options to predict: (1) the probability that a target stream
concentration (COC) will be exceeded due to the discharge from a facility; and (2) the number of
days per year the exceedence condition will exist. A simple mass balance approach forms the
basis of the model; however, the input variables are not single point estimates. Streams follow a
highly variable seasonal flow pattern and numerous variables in a manufacturing process can
affect the chemical concentration and flow rate of the effluent. PDM uses probability
distributions as inputs and calculates the resulting probability distribution of the concentration in
the stream. Additional information on PDM is available in the PDM Pathway discussion
(Section 4.0).
2.1.4 Revisions to GPE Model
EPA revised the GPE Model to utilize the most current readily available and accurate
facility and receiving stream information that would be consistent with data throughout the GPE
Pathway, as well as the Down-the Drain and PDM Pathways. These data are contained within
the E-FAST2 Main Facility File. In addition, a change in the approach used for statistical
calculations ensures that future updates of the GPE Model can be made efficiently and cost-
effectively.
As described in the above sections, the GPE Model has two options for performing
analyses: (1) site-specific and (2) generic (SIC Code). Input data for each option in the original
E-FAST GPE Model included facility discharge information for both direct and indirect
dischargers, which was maintained in two separate files.
Updated information for direct dischargers was compiled as part of EAB's new chemical
reviews. These data, obtained from a variety of information sources as shown in Figure 2-1 and
discussed in Section 2.2, are included in the E-FAST2 Main Facility File.
While the original E-FAST GPE Model used the most complete and readily available
data for indirect dischargers on a national level, limitations existed with these data. The
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Industrial Facilities Discharge (IFD) file, which was created in 1978 specifically to provide the
Office of Water with a comprehensive database of industrial dischargers including indirect
dischargers, served as the primary source of indirect discharger information in both the Site-
Specific and SIC Code Option of the original E-FAST GPE Model. However, the available data
for the indirect dischargers was outdated (i.e., last update in early 1990s and many of the
facilities once "active" were now "inactive;" new "active" facilities are not included) and
represented only a small fraction of the industrial plants that discharge to POTWs. In addition,
IFD is no longer supported by EPA.
EPA investigated alternative sources of indirect discharger information such as State
Files and other EPA databases. Limitations in obtaining and using data from these alternative
sources precludes their use at this time. Therefore, EPA determined that the use of indirect
discharger information in the E-FAST2 GPE Model would no longer be supported. As a result
of removing indirect discharger information from the E-FAST2 GPE Model, under the Site-
Specific Option, users are now only able to search for direct discharger information within the E-
FAST2 Main Facility File. To perform an analysis for an indirect facility, the user needs to
know the NPDES number (or some other identifying information such as the name and/or
location) of the POTW that receives the discharge.
Removal of indirect discharger information also affects analyses performed using the
generic (SIC Code) option in the E-FAST2 GPE Model. SDFP has been revised in the E-FAST2
GPE Model to only include the same data for direct dischargers (Main Facility File) as accessed
in the Site-Specific Option and to use an improved method of statistical calculations. As a result,
data are no longer available for 4 of the original 40 industries (Building Paper and Board Mills;
Photographic Processing; Plastic Products Manufacture; and Textile Dyeing and Finishing
(Carpets)). Therefore, the option to choose these industries has been removed from the model.
In addition, the "POTWs-Industrialized" category was originally based on POTWs that received
discharges from indirect facilities in select industrial categories (defined by SIC codes
1011-1999, 2211 -5199, 5 511 -5599, and 7211 -8099). In the E-FAST2 GPE Model, these
POTWs are selected based on their pretreatment designation in the Permit Compliance system
(PCS).
While the same methodology employed in the original SDFP option is used, the retrieval
of receiving stream data, calculation of dilution factors, and ranking of the flow data and
dilutions, are now all conducted within the E-FAST2 GPE Model. This will ensure that future
updates of the GPE Model will be made efficiently and cost-effectively.
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Additional revisions to the E-FAST2 GPE Model have also been made. The user may
now also specify up to three chemical concentrations of concern (the original E-FAST GPE
model allowed only one) for use in the calculation of days of exceedence.
An additional data search has also been included in the Site-Specific Option of the GPE
Model. The user may now search for a list of endangered species in the vicinity of a facility's
discharge to surface waters. The E-FAST2 GPE Model utilizes endangered species data
obtained from EPA's Endangered Species Protection Program (ESPP) Database (U.S. EPA,
2004) in conjunction with the Main Facility File.
As will be seen in the following sections, the updated Main Facility File in the E-FAST2
GPE Model contains all of the facility information and basic receiving stream information
necessary to be used by the two other surface water modules (Down-the-Drain, PDM) of E-
FAST2. (PDM and Down-the-Drain do require the use of additional files of statistical stream
data that are used in conjunction with the Main Facility File). Therefore, separate files of facility
and basic receiving stream information will no longer be used for each module, and when the
Main Facility File is updated, all of the surface water modules will be automatically updated.
2.2 Data Sources in GPE
The input data necessary for the GPE Model include (1) facility discharge information
and (2) estimated receiving stream flow data. GPE uses data from the E-FAST2 Main Facility
File. This file was created in 2002 by extracting various information from six water-related
information systems, as well as supplemental information. Three of these systems are no longer
being supported by EPA. However, some data elements in these systems are still valid and are
included in the Main Facility File as noted below. One additional source of information,
endangered species, is used in conjunction with the Main Facility File. Figure 2-1 presents an
overview of the surface water discharge information organization and sources for the E-FAST2
GPE Pathway. The basic program methodology used in the statistical calculations are
highlighted.
2.2.1 Facility Discharge Information
The information sources used to create the E-FAST2 Main Facility File are described
below, along with a description of the ESPP Database. As noted above, some of the systems are
no longer being supported by EPA, but, include data elements that are still valid and remain in
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the GPE Model. For those data elements available from multiple sources, a hierarchy was
established to ensure that the more accurate source of data was used. It is anticipated that
primary sources of information will continue to be maintained by EPA into the future. Sources
that are no longer supported by EPA have been archived and are available for any future updates
of E-FAST2. It should be noted that the date information was extracted from the various sources
may differ from the date the information was last updated within the source. This will be
especially true with sources that are no longer being supported by EPA. Both dates are
presented in the description, where possible, for each information source.
2.2.1.1 Permit Compliance System (PCS)
PCS is a national computerized management information system, maintained by the
Office of Enforcement and Compliance, that automates entry, updating, and retrieval of NPDES
data and tracks permit issuance, permit limits and monitoring data, and other data pertaining to
facilities regulated under NPDES. PCS was developed in 1974 and contains information for
more than 100,000 discharge permits (of which approximately 67,000 are active) issued to
facilities. PCS has extensive records on approximately 7,000 permits which are classified as
"major" based on the potential threat to human health or the environment. A separate permit
facility record exists for each NPDES number in the database.
PCS serves as the major source of direct discharging facilities in the E-FAST2 Main
Facility File. PCS is updated on a regular basis and is expected to continue to be supported by
EPA for many years. There are more than 1,400 data elements within PCS which have been
collected from State and EPA regions. The following data elements were retrieved and saved for
direct dischargers in the select industrial categories.
• NPDES number
Facility name and location
• Effluent flow
SIC code
Discharge status
Receiving stream name and reach number (limited availability)
Several limitations of PCS should be noted.
Only facilities that directly discharge to navigable waters and have a NPDES
permit are captured by PCS;
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PCS reports the primary SIC code for a facility that represents the principal
activity causing the discharge. Other activities may be ongoing at the facility that
would not be reflected in this code even if they contribute to the discharge;
Discharge Monitoring Reports (DMRs), which report facility discharge flow
values, are required only from major facilities. Major facilities account for
approximately 10 percent of the total number of facilities issued NPDES permits.
Because PCS is updated by States and EPA Regions on a continuous basis, the date of
extract may be considered the date of the most recent update of PCS. The most recent version of
PCS used in extracting data for the GPE Model is April 2002. Flow data were generated in 1996
using the Effluent Data Statistics System (EDSS) developed by EPA Region II. These data are
still considered valid at this time. In general, a facility's discharge flow remains consistent over
a period of time.
2.2.1.2 Task 73 Report
The Task 73 Report was originally created in the 1980's as a list of select U.S. industrial
facilities that manufacture organic chemicals. The list was created to support the efficient and
consistent assessments of exposures to PMNs received by OPPT under Section 5 of TSCA.
Over the years, the Task 73 Report grew as additional facilities that submitted PMNs were
added. In 1992 and 1997, site-specific dilution factors were added. The most current version of
the Task 73 Report contains information for 865 facilities including 474 direct discharging
facilities and 332 indirect discharging facilities.
Information contained in the Task 73 Report includes facility name and location,
discharge type, NPDES permit number (for the facility or the POTW receiving effluent),
receiving stream data, and comments/notes. All of the Task 73 Report's direct discharging
facilities, along with corresponding information, are included in the E-FAST2 Main Facility File.
Direct facilities that are no longer actively discharging are identified based on the discharge
status (active or inactive) in PCS. Each Task 73 Report record represents a single facility and is
keyed to the facility's or POTW's NPDES permit number. Information in the Task 73 Report
was compiled from a variety of sources including IFD, Gage, Needs Survey, SRI Directory of
Chemical Producers, State environmental departments, and PMN submitters.
The Task 73 Report was a valuable resource in preparing exposure assessments and
serves as a secondary source of information for direct dischargers in the GPE Model. In general,
the data in the Task 73 Report were verified by an EAB assessor at the time of collection and all
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of the facility names were checked every one to two years in the SRI Directory of Chemical
Producers and updated as needed. Because the data maintained in the database are limited
(outdated and missing many data points), PCS is used as the primary source of facility
information. Information from PCS has been incorporated into the E-FAST2 Main Facility File
for all of the Task 73 direct discharging facilities (active or inactive status). The Task 73 Report
data used in the GPE Model were compiled in November 1998. Data in the Task 73 Report were
last updated in 1997.
2.2.1.3 Industrial Facilities Discharge (IFD) File
IFD is an automated database of industrial and municipal point source dischargers to
surface waters in the United States. IFD was created in 1978 specifically to provide OW with a
comprehensive database of industrial dischargers including indirect dischargers. The last
version of IFD contains information for approximately 120,000 facilities, of which nearly half
are POTWs. There are approximately 130 data elements within IFD which have been collected
from various sources. Primary data sources in 1978 included:
PCS - PCS was used to identify NPDES permitted facilities;
NPDES Permit Files - Permits were accessed at the Regional EPA offices.
Discharge and location information was obtained for both direct and indirect
point source dischargers. States and local agencies provided additional and more
recent information; and
Needs Survey Data Files - The Needs Survey was used to add information on
existing POTWs identified by an NPDES number.
When a new NPDES number was issued, the facility was added to IFD. However, many
of the associated data elements (e.g., receiving stream information) were not completed for these
entries. Weekly review of reported gaps or errors were made. Updates were not performed in a
scheduled manner.
Facilities in IFD are keyed to the NPDES permit number. IFD also associates facilities
with waterways receiving their discharge by assigning U.S. Geological Survey (USGS)
hydrologic unit numbers and EPA's segment number (i.e., REACH number). Because some of
the information in IFD is out of date when compared to other source databases (e.g. PCS) and is
no longer supported by EPA, the Site-Specific Option of the GPE Model primarily uses IFD only
to identify the receiving stream name and reach number for direct dischargers. Complete
information (e.g., reach number) is not available for all facilities of interest. IFD is also used as
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a secondary source of effluent facility flow data. While the data may not accurately reflect
current conditions, approximately 24 percent of the effluent flow data used in E-FAST2 are
obtained from IFD. The most recent version of IFD used in the E-FAST2 Main Facility File is
November 1998 (extract date). Data in IFD were updated continuously until the early 1990s
when support of IFD was discontinued. IFD consisted of data extracted from other EPA
databases that were already scheduled for permanent retention.
2.2.1.4 Needs Survey
The Office of Wastewater Management (OWM) conducts the Clean Water Needs Survey
(CWNS) on a periodic basis. It is a joint effort between States and EPA conducted in response
to Section 205(a) and 516(b)(1) of the CWA. The CWNS has information on POTWs, facilities
for control of sanitary sewer overflows (SSOs), combined sewer overflows (CSOs), stormwater
control activities, nonpoint sources, and programs designed to protect the nation's estuaries.
Information obtained from the survey is maintained in an automated database and serves as the
basis for EPA's Report to Congress.
The last survey, available at the time of the data extract, was conducted in 1996. The
1996 CWNS database contains information on 16,024 wastewater treatment facilities.
Information for each POTW includes location and characteristics, construction cost estimates,
populations served, flow capacity, effluent characteristics, and treatment processes. Each facility
in the database is keyed to the NPDES permit number. The CWNS serves as a primary and
supplemental source of POTW information in the E-FAST2 Main Facility File. Information in
the CWNS that has been incorporated into the E-FAST2 Main Facility File includes the POTW
NPDES permit number, existing flow data (total and domestic), and populations served. The
most recent extractions of data from the 1996 CWNS were November 1998, and July 2004.
2.2.1.5 Supplemental File
In 2000, EPA generated a database containing locational data for all POTWs (identified
from PCS) in the United States. POTWs that did not have an assigned reach number (-9,300)
were identified and ranked by discharge flow. EPA then identified and assigned reach numbers,
using hydrologic unit maps, USGS topographic maps, and on-line digitized maps, to POTWs
that met the following criteria:
Missing an assigned reach number
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POTW discharge flow > 1MLD
Available latitude/longitude coordinates
Available receiving stream name
As a result of this effort, reach numbers and receiving stream flow values (as appropriate)
were identified and assigned to 315 POTWs. These data are included in the E-FAST2 Main
Facility File.
In addition, updated facility information was compiled as part of EAB's new chemical
reviews. These data were also updated into the E-FAST2 Main Facility File.
2.2.2 Receiving Stream Information
2.2.2.1 Gage File
The Gage File is an automated data file developed by OW to provide flow data on river
segments (reaches) that have been assigned a U.S. EPA reach number. The Gage File was
derived from the National Water Data Exchange, the Master Water Data Index, the Basic
Characteristics File, and the STORET Daily Flow System, which in turn is supplied by USGS.
There are approximately 36,000 records in the file. The stream flow data stored in the Gage File
include mean annual stream flow, 7Q10 (7-day-10-year) low flow, and flow velocities. Some of
the stream flow data in the Gage File are measured flows from USGS gaging stations which can
be located anywhere in the reach. Most of the stream flow data in the Gage File, however, are
estimated flow values. These estimated stream flows represent the downstream endpoints
(discharge) of reach segments, and are based on the best available measured flow data and on
drainage areas. The most comprehensive set of stream flow data were estimated by W.E. Gates
and Associates in 1982 (W.E. Gates, 1982) and account for approximately 99 percent of the
estimated flow values in the Gage File. Other estimated flow values in the Gage File (GKY,
IAS, GLCW) were developed for special studies conducted for streams of interest (i.e., not
specifically developed for the Gage File) or for connecting waterways within the Great Lakes
Region (e.g., Niagara River). (Versar, 1990) Some overlap may exist with the estimated flows
for a specific reach, however, the flows estimated by W.E. Gates and Associates are preferred,
based on their completeness.
The following data elements were retrieved (extracted) from the Gage File in March
1997/November 1998:
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WEG Station ID
Estimated mean annual and 7Q10 low flows
Receiving stream reach number
The Gage File is no longer an EPA supported database. However, the estimated flows
are still valid unless significant modifications have been made that affect the stream hydrology.
The W.E. Gates estimated flows are currently the only comprehensive set of flows available for
the national hydrologic database of stream segments (Reach File 1 - see below) which is used in
the E-FAST2 Main Facility File.
2.2.2.2 Reach File
The Reach File, developed by the Office of Water Regulations and Standards and
currently maintained by the Office of Wetlands, Oceans and Watersheds (OWOW), is a series of
national hydrologic databases of surface water features in the United States. It uniquely
identifies and divides each surface water into segments called reaches. Each reach is uniquely
identified by an eleven-digit REACH number. The three versions of the Reach File that
currently exist, known as Reach File 1 (RF1), RF2, and RF3, were created with increasingly
detailed sets of digital hydrography data. RF1 is used as the basis of many water quality
modeling applications today. RF1 contains information for 68,000 reaches covering
approximately 700,000 miles of streams. Information maintained for each reach includes:
Hydrologic structure, such as reach name, type, upstream and downstream
connections;
Reach trace, giving latitude and longitude coordinates along reaches; and
Open waterbody characteristics, such as surface area and perimeter.
Information in RF1, which was created in 1982, was based on NOAA aeronautical charts
and cataloging unit boundaries from the USGS. Data elements incorporated into the E-FAST2
Main Facility File include reach name and number and waterbody type. The Reach File
currently serves as the only source of data for surface water features. All information has been
verified by EPA with graphical and automated software tools. However, while most major rivers
and streams have been assigned a REACH number, there are waterways that have not been
divided into reaches.
A successor to the Reach File is the National Hydrography Dataset (NHD) Database. The
NHD is being developed as a joint effort between EPA and the USGS, and is being designed to
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accommodate and encourage the development of the higher resolution data needed by many
software applications (e.g., GIS). The OW is planning to use the NHD as a common framework
for interrelating data contained in the many EPA environmental databases such as PCS, and the
Safe Drinking Water Information System (SDWIS), and USGS Flow Data. All of the data from
the NHD are not yet available. The OW anticipates that flow values will be incorporated in NHD
in the near future. Several pilot projects are currently underway which would link data to NHD
including the OW models RiverSpill and PipelineNet. RiverSpill is a GIS based tool developed
to calculate the travel time, decay, and dispersion of a pollutant introduced into the surface
waters of a public water supply. PipelineNet is a companion model to RiverSpill and has been
developed to trace the path and concentration of toxic substances within a water pipeline
network. In addition, pilot studies are underway to assign estimated stream flows to the NHD
reaches and to develop a cross reference from NHD to RF1. Once NHD has been completed,
EPA will no longer support the Reach File.
2.2.3 Stream Dilution Factor Program (SDFP)
SDFP was originally developed by OW to obtain effluent and stream flow frequency
distributions for a given industrial category or SIC code(s). SDFP was revised in 1987 to meet
the needs of OPPT. Since 1987, the program has been periodically revised to include updated
data, new variables, as well as changes in the program logic. The major purpose of SDFP is to:
(1) retrieve receiving stream flow data for facilities in a particular industry or SIC code(s); (2)
calculate dilution factors for each facility (receiving stream flow divided by effluent flow); and
(3) rank the flow data and dilution factors and report the results in terms of percentiles. SDFP
calculates these values, for all of the selected industries, based on the facility and receiving
stream information in the E-FAST2 Main Facility File. When an SIC code or industry-based
analysis is performed, GPE uses the 10th and 50th percentile receiving stream flows to estimate
flows for a representative facility in the selected industry.
2.2.4 Endangered Species Database
The Endangered Species data in E-FAST2 is used to identify the endangered species
known (or possible) to exist in the vicinity of streams and rivers that receive wastewater
discharges containing the chemical of concern. The location of endangered species is correlated
with the facility location via FIPS State and county codes in the E-FAST2 Main Facility File.
The endangered species information includes common name, county and State, taxonomic group
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(e.g., mammals, birds, fish, plants, reptiles, amphibians, clams, etc.), listing action (listing,
proposed, delisting), and occurrence. The data were extracted from EPA's Endangered Species
Protection Program (ESPP) Database (February 2004 release). The ESPP is a cooperative effort
between the U.S. Fish and Wildlife Service (FWS), EPA Regions, States, and pesticide users.
ESPP is located in the Field and External Affairs Division (FEAD) of the Office of Pesticide
Programs (OPP).
2.3 Hierarchy Used in Selection of Data Elements
Twenty-three data elements for direct discharges were compiled from the various water-
related environmental systems to be included in the E-FAST2 Main Facility File. Since the same
data element(s) may be available from more than one database, a hierarchy was established to
ensure that the more accurate sources of data are used. Table 2-1 presents a list of the various
data elements compiled for direct dischargers for use in E-FAST2. For a given data element,
sources are presented based on the hierarchy established for the Main Facility File in E-FAST2.
Not all of the data elements were compiled directly from the various sources. The estimated
mean and 7Q10 (lowest 7-consecutive day average flow that occurs every 10 years) flow values
extracted from the Gage File were used to estimate the harmonic mean (inverse daily flow),
1Q10 (lowest 1-day average flow that occurs every 10 years), and 30Q5 (lowest 30-consecutive
day average flow that occurs every 5 years) flow values.
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Table 2-1 - Data Elements Included in E-FAST2 Main Facility File of Direct Dischargers*
Data l-lcnicnl
Source
Commenls
NPDES Number
PCS, Task 73
Serves as major linkage between databases
Company Name
PCS, Task 73

City
PCS, Task 73

State
PCS, Task 73

State/County FIPS Code
PCS

Zip Code
PCS

SIC Code
PCS
Facility Level
Discharge Type
PCS, Task 73
Direct
Discharge Status
PCS
Inactive (I) or Active (A)
Facility Flow
NEEDS, PCS, IFD
Total Facility Flow/Domestic POTW Flow
Receiving Stream Name
Task 73, IFD, PCS

Reach Number
Task 73, IFD, PCS
Serves as linkage between databases
Reach Name
REACH

HIT Code
IFD
Located on Reach - Yes, No or Unknown
Water Body Type
REACH
River or Estuary/Lake
Mean Flow
GAGE
Estimated WEG flow
Harmonic Mean Flow
Calculated
Calculated
7Q10 Flow
GAGE
Estimated WEG flow
30Q5 Flow
Calculated
Calculated
1Q10 Flow
Calculated
Calculated
Acute Dilution Factor
Task 73
Mixing Zone Critical Dilution Factor
Chronic Dilution Factor
Task 73
Mixing Zone Critical Dilution Factor
Population Served
NEEDS
Population serviced by POTW
* Additional data elements are available but are not currently included in E-FAST2.
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Module 2
Main Facility File
estimated
flows
H Information Source
WEG Sites
Main Facility File
All POTWs
Probability
Statistical
Calculation
All POTWs Statistical
Calculation (SDFP)
Calculate percentile
dilution factors for
POTWs
Basin Coefficient
Statistical Fileb
Extract: 1991
Calculate average and
high-end exceedence
probability for all POTWs
Calculate exceedence
probability using Di Toro
Algorithm for all POTWs
Drinking Water
Exposure
Fish Ingestion
Exposure
Aquatic Exposure
Footnotes:
a. See Probabilistic Dilution Model Pathway
b. Used in conjunction with Main Facility File
Note: Extract date may differ from date of
Source's last update. See text for details.
Down-the-Drain Pathway
Figure 3-1
Exposure and Fate Assessment Screening Tool, Version 2.0 (E-FAST2)
Down-the-Drain Pathway
(Surface Water Discharge Information Organization and Sources)
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3.0 DOWN-THE-DRAIN PATHWAY
3.1 Background
The Down-the-Drain Pathway is a screening level model for estimating concentrations of
chemicals in surface waters that may result from the disposal of consumer products into
household wastewater. The model assumes that household wastewater undergoes treatment at a
local wastewater treatment facility and that treated effluent is subsequently discharged into
surface waters. The model provides estimates of aquatic exposure and human exposure from
ingestion of drinking water and fish that may become contaminated by these household
wastewater releases. In addition, a user may select PDM to estimate the number of days per year
that the concentration of a chemical in surface water exceeds the level of concern for aquatic life.
The Down-the-Drain model was originally developed for EPA in 1989 as the software program
entitled FLUSH. Revisions were made in 1991 and 1992.
Chemical constituents of some household products (e.g., detergents) are expected to end
up in household wastewater. Chemical constituents of other household products are not likely to
enter wastewater (e.g., fragrance in an air freshener). The physical-chemical properties and the
functional role of the chemical in a product should always be evaluated prior to implementing
Down-the-Drain because these properties could preclude the presence of the chemical in
household wastewater.
Based on user-specified annual production volume (mass of chemical produced annually
or discharged annually to wastewater by consumers) and the U.S. population, Down-the-Drain
estimates the total daily per capita release of a chemical in household wastewater. The
household daily release and stream dilution factors, along with the user-specified wastewater
treatment efficiency, are then used to calculate a screening-level estimate of the time-averaged
surface water concentration (high-end and median) of a chemical substance released by a
wastewater treatment facility receiving household wastewater (assuming all wastewater entering
a treatment facility is from residential sources). Surface water concentrations are estimated
under four receiving stream flow conditions (1Q10 low flow, 7Q10 low flow, 30Q5 low flow,
and harmonic mean flow) as described below, using the mean stream dilution factors for all
wastewater treatment facilities based on 10th and 50th percentile values.
Surface water concentrations are estimated in rivers and streams under the four receiving
stream flow conditions as recommended in the Technical Support Document for Water Quality-
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based Toxics Control (U.S. EPA, 1991). Harmonic mean flows are used to generate estimates of
chronic human exposure via drinking water and fish ingestion. EPA defines the harmonic mean
flow as the inverse mean of reciprocal daily arithmetic mean flow values. EPA recommends
using the long-term harmonic mean to assess potential human health impacts because it provides
a more conservative estimate then the arithmetic mean flow. The 30Q5 flows (lowest
consecutive 30-day flow during any five-year period) are used to generate estimates of acute
human exposure via drinking water. To estimate potential acute and chronic aquatic life impacts,
the model uses 1Q10 and 7Q10 flows, which are the lowest 1-day and the lowest consecutive 7-
day average flows during any 10-year period, respectively. The stream data used are estimated
flows at the downstream end of specific stream segments (reaches), and presumably include the
discharge flow from any facility on that reach. Stream flows used in Down-the-Drain are corrected
in the same manner as those in the GPE pathway (See Section 2.1).
Down-the-Drain incorporates PDM to predict the number of days a COC will be
exceeded due to the discharge from a POTW. A simple mass balance approach forms the basis
of PDM; however, the input variables are not single point estimates. Streams follow a highly
variable seasonal flow pattern and numerous variables affect the chemical concentration and
flow rate of the effluent. PDM uses probability distributions as inputs and calculates the
resulting probability distribution of the concentration in the stream. Additional information on
PDM is available in Section 4.0 of this report. The version of PDM in Down-the-Drain uses a
typical per capita release (instead of discharge loading) to generate POTW loadings by
multiplying estimates of population served by estimates of per capita household releases. Not all
of the POTWs listed in the Main Facility File have the population and stream flow values required
for this version of PDM, so the subset of 8,304 facilities with both values serves as the data source.
As seen in Figure 3-1, Down-the-Drain has two analyses available to the user: (1)
estimating the surface water concentrations (SDFP) and (2) estimating the number of days a
chemical concentration exceeds a COC (PDM). Revisions to both of these analyses were recently
completed and are described in the following section. The data sources used in Down-the-Drain
are described in Section 3.2.
3.1.1 Revisions to Down-the-Drain
EPA revised Down-the-Drain to utilize the most current readily available and accurate
facility and receiving stream information that would be consistent with data used throughout all
pathways of E-FAST2. This data is contained within the E-FAST2 Main Facility File. In
addition, a change in the approach used for statistical calculations has been made. The improved
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method of statistical calculations and use of the E-FAST2 Main Facility File ensures that future
updates of Down-the-Drain can be made efficiently and cost-effectively.
In the original E-FAST Down-the-Drain, IFD served as the major source of POTW
information in estimating surface water concentrations. However, IFD, which was created in
1978 specifically to provide OW with a comprehensive database of industrial dischargers, is an
outdated database and is no longer supported by EPA. The E-FAST2 Down-the-Drain uses the
most current information for POTWs that is readily available from the E-FAST2 Main Facility
File. Updated information for direct dischargers was compiled as part of EAB's new chemical
reviews. These data, obtained from a variety of information sources as shown in Figure 2-1 and
discussed in Section 2.2 of the GPE Pathway, are included in the E-FAST2 Main Facility File.
Only information for POTWs are used in Down-the-Drain. In addition, retrieval of receiving
stream data, calculation of dilution factors, and ranking of the flow data and dilutions are all now
conducted within Down-the-Drain in E-FAST2. The same methodology employed in the
original SDFP is used.
The POTW information and method of statistical calculations used in the probability
calculations (PDM) in Down-the-Drain has also been revised in E-FAST2. POTW information
and basic receiving stream information are now obtained from the E-FAST2 Main Facility File.
One additional file (the Basin Coefficient Statistical File) is used in conjunction with the
E-FAST2 Main Facility File. Direct calculation of exceedence probability is conducted as
described in Section 4.0 of this report.
3.2 Data Sources in Down-The-Drain
In estimating surface water concentrations (SDFP) and the probability of exceeding
concentrations of concern (PDM), Down-the-Drain uses facility and basic receiving stream
information from the E-FAST2 Main Facility File, SDFP, and the Basin Coefficient Statistical
File. Figure 3-1 presents an overview of the surface water discharge information organization
and sources for the E-FAST2 Down-the-Drain Pathway. The basic program methodology used
in the statistical calculations are highlighted.
3.2.1 E-FAST2 Main Facility File
The E-FAST2 Main Facility File contains facility information and basic receiving stream
information for over 27,000 direct discharging facilities. The file was created in 2002 by
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extracting various information from six water-related information systems (PCS, Task 73 Report,
IFD File, Gage File, Reach File, Needs Survey), as well as supplemental information
(Supplemental File). Three of these systems are no longer being supported by EPA. However,
some data elements in these systems are still valid. The file is used by all three surface water
modules (GPE, Down-the-Drain, PDM) of E-FAST2. Separate files of facility and basic
receiving stream information are no longer used for each module and when the Main Facility
File is updated, all of the surface water modules will be automatically updated. More
information on the data sources used to create the E-FAST2 Main Facility File is available in
Section 2.2 of this report.
The per capita household wastewater volume (QH in units of volume/person/time) was
derived from the 1996 Clean Water Needs Survey (CWNS or Needs) data contained in the Main
Facility File. Using the same selection method as the original Down-the-Drain module, the
following data were selected:
• POTW domestic (residential-source) flows that were less than or equal to total flows
• Resident population served by the POTW.
After correcting for data outliers- those values above the 95th percentile (1,003 liters per
capita per day)-- the distribution of QH values was calculated, based on data from 12,019
POTWs. The 50th percentile of this data set- 388 L/person/day- was selected as the representative
daily per capita wastewater volume (QH) released in Down-the-Drain.
3.2.2 Stream Dilution Factor Program
Surface water concentrations are estimated using the 50th and 10th percentile stream
dilution factors for streams to which wastewater treatment facilities discharge. The stream
dilution factor is equal to the volume of the receiving stream flow under the four flow conditions
divided by the volume of the wastewater treatment facility effluent flow. These values are
calculated within the Down-the-Drain model for all active POTWs using SDFP.
SDFP was originally developed by the OW to obtain effluent and stream flow frequency
distributions for a given industrial category or SIC code(s). SDFP was revised in 1987 to meet
the needs of OPPT. Since 1987, the program has been periodically revised to include updated
data, new variables, and changes in the program logic. SDFP is designed to: (1) retrieve
receiving stream flow data for facilities in a particular industry or SIC code(s); (2) calculate
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dilution factors for each facility (receiving stream flow divided by effluent flow); and (3) rank
the flow data and dilution factors and report the results in terms of percentiles. In Down-the-
Drain, SDFP calculates these values from 9,619 POTWs in the E-FAST2 Main Facility File that
have both effluent and stream flow information. This SDFP use is consistent with the use of
SDFP for SIC categories in the GPE module (see Section 2.1.2).
3.2.3 Basin Coefficient File
The USGS has divided the U.S. into 18 hydrological river basins or watersheds,
subdivided into 204 sub-basins. The flow behavior of streams within each sub-basin is unique,
and requires statistical coefficients of variation specific to each sub-basin. The Basin Coefficient
File contains coefficients that allow stream flow variation to be calculated for a given sub-basin,
mean stream flow, and low (7Q10) flow.
The basin coefficients were derived from measured coefficients of variation, estimated
(WEG) mean flow, and low (7Q10) receiving stream flow, obtained from the Gage File in 1991.
Data were analyzed by basin and sub-basin, identified by the first four digits of the 11-digit
reach number of a POTW's receiving stream. Coefficients of variation for the stream flows were
then calculated for each basin/sub-basin using regression analyses. The coefficients are then
used in the probability calculations to account for the flow variability that may occur in a
particular stream when estimated flows are used.
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Module 4
Probabilistic Dilution Model (PDM) Pathway
Aquatic Environment
Exposure / Risk
I
Site-
Specific
I
SIC
Code
Site-Specific Probability
Statistical Calculation
Main Facility File
measured
flows
i— USGS Stations
STORET Daily Flow
Statistical File3
Extract: 1991
estimated
flows
WEG Sites
All Facilities Probability
Statistical Calculation

| Main Facility File ||

estimated
flows

WEG Sites
Basin Coefficient
Statistical File3
Extract: 1991
Basin Coefficient
Statistical File3
Extract: 1991
Calculate
exceedence
probability using
percentile flows
IDI Information Source
Calculate
exceedence
probability using
Di Toro Algorithm
Footnote:
a. Used in conjunction with Main Facility File
Note: Extract date may differ from date of
Source's last update. See text for details.
Calculate exceedence
probability using Di
Toro Algorithm for each
facility in selected
industrial category
Calculate average and
high-end exceedence
probability for industrial
category
Figure 4-1
Exposure and Fate Assessment Screening Tool, Version 2.0 (E-FAST2)
Probabilistic Dilution Model (PDM) Pathway
(Surface Water Discharge Information Organization and Sources)
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4.0 PROBABILISTIC DILUTION MODEL (PDM) PATHWAY
4.1 Background
The Probabilistic Dilution Model (PDM) is used for predicting downstream chemical
concentrations from an industrial discharge. It calculates the probability that a given target
stream concentration will be exceeded, and the number of days per year the exceedence
condition will exist. PDM was originally developed for EPA in 1986 with revisions made in
1987,1988 (Versar, 1988), and 1991. PDM was included as part of the original E-FAST in 1999
and was revised for E-FAST2. A simple mass balance approach forms the basis of the model;
however, the input variables are not single point estimates. In reality, these variables are not
constant; streams follow a highly variable seasonal flow pattern and numerous variables in a
manufacturing process can affect the chemical concentration and flow rate of the effluent. PDM
uses probability distributions as inputs and calculates the resulting probability distribution of the
concentration in the stream. See Appendix C for an explanation of PDM's statistical framework.
The calculation of probability assumes that receiving stream flow, effluent flow, and
effluent concentration are log-normally distributed. The statistics involve both the arithmetic
and logarithmic forms of the mean and coefficient of variation (i.e., standard deviation/mean) for
the flow and concentration of both the stream and the effluent. PDM utilizes default values for
the coefficients of variation for effluent flow and concentration from EPA's Technical Guidance
Manual for Performing Waste Load Allocations, Book VII: Permit Averaging Periods (U.S.
EPA, 1984). PDM can predict frequency of exceedence of the concern concentration in streams
that have a record of flow data from gaging stations as well as in streams without gaging
stations. As seen in Figure 4-1, PDM has two options available for performing analyses,
depending on the data available. The first option addresses site-specific cases. The second
option allows for a high-end or average-case analysis of potential exceedence for an unspecified
facility in an industrial category or specific SIC Code(s). This option serves as a screening level
analysis to assess the impacts of potentially thousands of facilities in a given SIC Code. The
following sections briefly describe the two options, as well as revisions to PDM.
4.1.1 Site-Specific Option
The Site-Specific Option is selected when the NPDES number of the discharging facility
is known. PDM locates the facility in the E-FAST2 Main Facility File and then determines
whether the associated receiving stream has measured (USGS gaging station), estimated (W.E.
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Gates and Associates), or no flow data. Upon entering the number of release days, loading (i.e.,
mass of chemical discharged per day), and a COC for the protection of aquatic life, the model
determines the frequency (i.e., number of days per year) that the receiving stream's
concentration will exceed the concern level.
For reaches with gaging stations, daily flow data from the STORET Daily Flow
Statistical File are ranked and flows representing the 1st to 100th percentiles (in 1 percentile
increments; N=100) are selected for each station (if a gaging station has less than 100 daily flow
values, percentiles are not calculated). PDM reports the station ID number, number of
observations, period of record, 50th and 10th percentile flows, and the number of stations on each
receiving reach. The concentration for each percentile flow is calculated by dividing the loading
rate by the percentile flow. The COC is then compared with the 100 calculated concentrations
and the highest percentile flow that yields a concentration greater than the COC is selected. The
percent of year, as well as the days per year, the COC is exceeded are calculated based on the
selected percentile.
For reaches without gaging stations, PDM calculates the exceedence probability using a
stochastic procedure developed by Di Toro (1984). This approach requires the means and
coefficients of variation of stream flow, effluent flow, and effluent concentration as input. Mean
stream flow and mean effluent flow are provided by the E-FAST2 Main Facility File. The
stream flow coefficient of variation is estimated using the mean stream flow, low stream flow
(7Q10, also available in the E-FAST2 Main Facility File) and empirically-derived coefficients
specific to each subbasin that are available in the Basin Coefficient Statistical File. The
coefficients of variation of effluent flow and concentration are assumed to be 0.24 and 0.85,
respectively (U.S. EPA, 1984). Following entry of chemical loading and the COC, the
probability of exceedence is calculated by PDM using the Di Toro algorithm.
4.1.2 SIC Code Option
The SIC Code Option is selected when the location (i.e., facility and receiving stream) of
a chemical loading is unknown and only the representative industrial category is known. This
option uses the same calculation as the Site-Specific Option (estimated flows only) except that
the calculations are performed for numerous facilities to calculate an average-case or high-end
probability of exceedence in an industrial category. This analysis represents the average and
high-end 10% exceedence probability of facilities for the industrial category, COC, and loading
rate.
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4.1.3 Revisions to PDM
EPA revised PDM to utilize an approach that would be more transparent and flexible.
Such an approach uses the most current readily available data and is consistent with data used in
the other pathways of E-FAST2 (GPE and Down-the-Drain). The approach developed ensures
that future updates of PDM can be made efficiently and cost-effectively.
As described in the above sections, PDM has two options for performing an analysis:
site-specific and generic (SIC Code). The most current information for direct dischargers was
compiled as part of EAB's new chemical reviews and are contained within the E-FAST2 Main
Facility File. These data were obtained from a variety of sources as discussed in Section 2.2 of
this report and were updated into the Site-Specific Option of the original E-FAST PDM Model
in April 2002.
IFD (extract 1991) served as the major source of facility information in the SIC Code
Option of the original E-FAST PDM. However, IFD is an outdated database (i.e., many of the
facilities once "active" are now "inactive"; new "active" facilities are not included). Data for
indirect facilities is outdated and represents only a small fraction of the industrial plants that
discharge to POTWs. In addition, IFD is no longer supported by EPA. The SIC Code Option of
the E-FAST2 PDM now uses the most current direct facility information that is readily available
from the E-FAST2 Main Facility File. Data for the industrialized POTW category are now
based on a POTWs pretreatment designation in PCS rather than POTWs that receive discharges
from indirect facilities in select industrial categories.
The original E-FAST PDM required statistical "matrix files" when calculating
probability of exceedence by SIC code. The matrix files were created by performing many
thousands of stochastic calculations and storing the results in "look-up" tables. The matrix files
were created using facility data from the SIC code groups in 1992 and included both direct and
indirect facilities. Although this original method increased the speed of PDM, it required that
the matrix files be modified each time an update was made to the SIC code database. Updating
the data in the SIC Code Option caused the matrix files to be out of date. Additionally, the data
stored within the matrix files had to be interpolated before they were used by PDM. The E-
FAST2 PDM performs the probability of exceedence calculations within PDM rather than using
a matrix probability/ratio/interpolation method, and makes the use of matrix files obsolete. The
internal data structures within E-FAST2 have been updated to accept the revised PDM code.
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Another revision to PDM involves how the 7Q10 stream flow is corrected. In some cases,
the mean effluent flow from a facility is greater than the estimated 7Q10 flow of the receiving
reach. This may be a case where the facility effluent flow is intermittent, and the 7Q10 flow for
the reach represents the stream flow at the time of zero or low effluent flow. In E-FAST2, to
represent the stream flow in the vicinity of the facility, the greater of the following two flows is
used: (1) the effluent flow for the facility of interest or (2) the stream flow (Personal
communication from Russell Kinerson, U.S. EPA/Office of Water, to Conrad Flessner, U.S.
EPA/OPPT, March 2005).
The PDM portion of the original E-FAST follows this convention and sets the 7Q10
and/or mean stream flows equal to the effluent flow if they are less than the effluent flow. Next,
waste-load correction factors are applied and a corrected COC is determined, prior to calculating
the exceedence probability. Previously, for the waste-load correction factors, if the 7Q10 flow
was greater than the effluent flow, the corrected COC was based on the 7Q10 flow only.
Otherwise, the corrected COC was based on the 7Q10 flow plus the effluent flow. However, for
those cases where the 7Q10 flow was already set equal to the effluent flow (i.e., if the 7Q10 flow
was originally reported as less than the effluent flow, as described above and in Section 2.1), the
7Q10 flow was artificially high, and the corrected COC was essentially based on twice the
effluent flow. This second set of stream flow modifications was removed from PDM, such that
the corrected COC is based solely on the first modification made to the 7Q10, with no additional
flow corrections made in PDM.
4.2 Data Sources in PDM
The input data necessary for PDM include: (1) facility information and estimated
receiving stream flow data from the E-FAST2 Main Facility File, values which are also currently
used in both the GPE and Down-the-Drain Pathways of E-FAST2, (2) percentile stream flow
values (where available), and (3) coefficients of stream flow variations.
4.2.1 E-FAST2 Main Facility File
The E-FAST2 Main Facility File contains facility information and basic receiving stream
information for over 27,000 direct discharging facilities. The file was created in 2002 by
extracting various information from six water-related information systems (PCS, Task 73 Report,
IFD File, Gage File, Reach File, Needs Survey), as well as supplemental information
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(Supplemental File). Three of these systems are no longer being supported by EPA. However,
some data elements in these systems are still valid. The file is used by all three surface water
modules (GPE, Down-the-Drain, PDM) of E-FAST2. Separate files of facility and basic
receiving stream information are no longer used for each module—so when the Main Facility
File is updated, all of the surface water modules are automatically updated. More information on
the data sources used to create the E-FAST2 Main Facility File is available in Section 2.2 of this
report.
4.2.2 STORET Daily Flow Statistical File
The STORET Daily Flow System (DFS) serves as the source of daily flow values for the
Site-Specific Option in PDM. The STORET Flow File was an automated database that was
maintained by OW and was one of the three main information areas of STORET. It contains
daily observations of stream flow and miscellaneous water quality parameters collected at gaging
stations belonging to the U.S. Geological Survey's National Network. The DFS contains
essentially the same information as the USGS Flow Files and serves as an alternative source for
the information and simplifies linkages to other, non-USGS water databases. The system
contains information for more than 700,000 records, each representing a single water year's
worth of information, for over 29,585 gaging sites. USGS supplied new flow data into the file
on a biannual basis. The file currently used by PDM contains data up to February 1991. With
the modernization of STORET and Y2K, all data owned by USGS has been removed from
STORET and is now only available directly from USGS.
Several limitations of the STORET DFS should be noted:
1) Information is out-of-date when compared to other source databases (USGS).
Daily stream flow data since 1991 are not included; however, the data collected
from 1966 to 1991 are still valid unless significant modifications have been made
that affect the stream hydrology.
2) Only 12 percent of the facilities of interest to EAB are located on receiving
streams with available daily flow values.
3) STORET DFS is no longer an EPA supported database. The most recent version
of DFS used in extracting data for PDM is 1991.
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4.2.3 Basin Coefficient File
The USGS has divided the U.S. into 18 hydrological river basins or watersheds,
subdivided into 204 sub-basins. The flow behavior of streams within each sub-basin is unique,
and requires statistical coefficients of variation specific to each sub-basin. The Basin Coefficient
File contains coefficients that allow stream flow of variation to be calculated for a given sub-
basin, mean stream flow, and low (7Q10) flow.
The basin coefficients were derived from measured coefficients of variation, estimated
(WEG) mean flow, and low (7Q10) receiving stream flow obtained from the Gage File in 1991.
Data were analyzed by basin and sub-basin, identified by the first four digits of the 11-digit
reach number of a facility's receiving stream. Coefficients of variation for the stream flows were
then calculated for each basin/sub-basin using regression analyses. The coefficients are then
used in the probability calculations to account for the flow variability that may occur in a
particular stream when estimated flows are used.
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5.0 REFERENCES
Di Toro, D. M. 1984. "Probability Model of Stream Quality Due to Runoff. ASCE." Journal
of Environmental Engineering. 110(3):607-628.
U.S. Environmental Protection Agency. 1984. Technical Guidance Manual for Performing
Waste Load Allocations. Book VII. Permit Averaging Periods. Washington, DC: Office
of Water Regulations and Standards. EPA 440/4-84-023.
U.S. EPA. 1991. Technical Support Document for Water Quality-Based Toxics Control. Office
of Water. EPA/505/2-90/001.
U.S. EPA. 2004. Endangered Species Protection Program (ESPP) Databases (February 2004
release). Office of Pesticide Programs.
Versar, Inc. 1988. Probabilistic Dilution Model 3. EPA Contract No. 68-02-4254. Task No.
117. May 1988.
Versar, Inc. 1990. Final Draft Report, Aquatic Exposure Data Bases and Tools. Prepared for
U.S. EPA, Office of Toxic Substances. EPA Contract No. 68-D9-0166. Task 36. July 25,
1990.
Versar, Inc. 1992a. Mixing Zone Dilution Factors for New Chemical Exposure Assessments.
Prepared for U.S. EPA, Office of Pollution Prevention and Toxics. EPA Contract No. 68-
D9-0166, Task No. 3-35.
Versar, Inc. 1992b. Upgrade of Flow Statistics Used to Estimate Surface Water Chemical
Concentration for Aquatic and Human Exposure Assessment. Prepared for U.S. EPA,
Office of Pollution Prevention and Toxics. EPA Contract No. 68-D9-0166, Task No. 3-48.
Versar, Inc. 1997. Development of Mixing Zone Dilution Factors. Prepared for U.S. EPA, Office
of Pollution Prevention and Toxics. EPA Contract No. 68-D3-0113, Task No. 2-12.
W. E. Gates and Associates, Inc. 1982. Estimation of Streamflows and the Reach File.
Prepared for the U.S. Environmental Protection Agency, Office of Water, Monitoring
Branch.
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Appendix C
Statistical Framework of Probabilistic Dilution Model (PDM)
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THE PROBABILISTIC DILUTION MODEL
Introduction
The Probabilistic Dilution Model (PDM) predicts the likelihood that a chemical
concentration downstream of a discharger will exceed a target concentration of concern (COC).
PDM estimates stream concentration for a given flow condition using a simple dilution model,
then predicts the exceedence probability based on the variability of stream or effluent flow.
PDM may be applied to a single facility or for all facilities within an industrial category. If the
user selects the all facilities option, PDM predicts the exceedence probability for each facility in
an industrial category and then reports the 50th and 10th percentile results. The current version of
PDM (PDM 4) calculates exceedence probability in a fashion similar to previous versions.
However, increases in desktop computer speed allow exceedence probability to be directly
calculated for all facilities within an industrial category; previous versions of PDM required a
mainframe computer to calculate intermediate matrix files that were stored within PDM for use
by desktop computers. This revised approach is both simpler and more accurate than previous
versions because it automatically reflects updates to the facility data source, the E-FAST2 Main
Facility File (see Appendix B), without the need for the intervening matrix files. The specific
approaches employed by PDM for the three options (single facility with actual flows, single
facility with estimated flows, and all facilities in an industrial category) are described below.
Case I: Exceedence Probability for a Single Facility with Actual Flows
PDM uses actual flow statistics to calculate the exceedence probability for facilities that
discharge to stream reaches containing gaging station data. PDM first calls the E-FAST2 Main
Facility File to identify the reach associated with the facility, then searches the database to
determine if flow statistics are available for that reach. The database stores 100 percentile daily
flows (in 1-percentile increments) for the entire record of each gaging station. PDM then
calculates the concentration for each percentile flow as:
CS = L/P(QS) Eq. 1
where Cs is the concentration downstream of the discharging facility, L is loading, and Qs is the
stream discharge rate associated with the percentile, PQ. PDM then finds the critical percentile
flow at which the COC is exceeded, and reports this value as the exceedence probability.
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Results are more likely to be accurate by this approach because actual (not estimated)
flow data are used. In addition, this method does not assume that stream flow follows a
particular stochastic distribution. Unfortunately, actual flow data are available for fewer than
1% of reaches in the United States, so this approach is rarely an option.
Case II: Exceedence Probability for a Single Facility with Estimated Flows
For cases where actual flow data are unavailable, PDM estimates the exceedence
probability using the Di Toro (1984) method. The Di Toro approach is based on a simple
dilution governing equation:
Cs = Ce/(l+R) Eq.2
where Ce is the facility effluent concentration and R is the dilution ratio. This equation may be
used to calculate Cs directly if Ce and R are known. However, to be used as a predictive tool, the
variability of each of these parameters should be considered. PDM accounts for variability by
assigning stochastic distributions to these parameters. PDM assumes that these parameters are
lognormal, and can be represented by their logarithmic means (juCe and «,.) and standard
deviations (oCe and or), respectively. Once these are known, the probability that the stream
concentration will exceed the concentration of concern, P(CS > COC), may be calculated as:
P(Cs > COC) = 1 - I Q
o
ln(COCC0KEECTED)+ln [1 + exp(^ir + Q (x))] -£tc
ck Eq. 3
where Q(x) is the standard normal cumulative distribution function (CDF) and Q~'{x) is the
inverse standard normal CDF.
PDM solves Equation 3 using numerical integration (32-point Laguerre quadrature) and
polynomial approximations of the normal and inverse-normal CDFs.
The following input parameters are required to run PDM using estimated flows:
Reach basin and sub-basin, available from the Reach ID in the E-FAST2 Main
Facility File;
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Arithmetic mean effluent flow rate, nQe, available in the E-FAST2 Main Facility
File;
Arithmetic mean stream flow rate, juQs, available in the E-FAST2 Main Facility
File (originally derived from the W.E. Gates & Associates study, 1982);
Arithmetic low stream flow rate, Qs 7QI0, available in the E-FAST2 Main Facility
File (originally derived from the W.E. Gates & Associates study, 1982);
Arithmetic coefficient of variation of effluent flow rate, vQe, default set to 0.24
(from US EPA, 1984);
Arithmetic coefficient of variation of effluent concentration, vCe, default set to
0.85 (from US EPA, 1984);
Arithmetic daily loading rate, L, provided by the user; and
Arithmetic concentration of concern, COC, provided by the user.
Several of these parameters require correction factors and transformation before they
may be utilized by Equation 3, as outlined below:
Step 1: Modify mean and low stream flow if they are less than mean effluent flow
PDM checks to assure that mean and low stream flow (juQs and Qs 7QI0) are equal to or
greater than the mean effluent flow (juQe). If the low or mean stream flow value is less than uQc,
the low or mean stream flow value is set equal to nQe, respectively (Personal communication
from Russell Kinerson, U.S. EPA/Office of Water, to Conrad Flessner, U.S. EPA/OPPT, March
2005).
Step 2: Estimate the coefficient of variation for stream flow
The coefficient of variation for stream flow (vQs) is determined from an empirical
relationship between juQs, Qs -(jl0, and two coefficients (a and b) specific to the reach's sub-basin
as follows:
v& =exf> (a - b (Qsjqio / u^j) Eq. 4
These basin coefficients {a and b) were established for each sub-basin in the United
States by Versar in 1988, and are currently stored within the source code of PDM. If the sub-
basin or basin are unknown, PDM supplies basin- or nation-wide basin coefficients.
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Step 3: Apply the waste-load correction factors
PDM employs a normalization scheme using the modified (corrected) 7Q10 from Step 1.
The corrected COC is calculated as follows:
COC £
-CORRECTED
COC(Q S m 7QIQ _ corrected)
L
Eq. 5
Step 4: Calculate the log-transformed means and standard deviations of effluent concentration
and dilution ratio
In this final step, the corrected variables are log-transformed to estimate fxce, occ, un and or
as follows:
Mce = ln
/ A
1 + Qs _7gl0 _CORRECTED 'Age
$
+ V
Ce
Eq. 6
(jc, = ^ln(\ + v2Ce)
Eq. 7
if (Mqs = VQe) then //r = In
f \
/fa
v/'av
+ ln(V1+ ve.)~ ln(V1+v&) Eci 8
else jlr = In
^ Pq, J
+ lnU/1+|,a)"ln(V^
a
Eq. 9
q - ^ln(l + ) + /»(1 + )
Eq. 10
These parameters may now be used in Equation 3 to calculate exceedence probability.
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Case III: Exceedence Probability for an Industrial Category
PDM is often used to estimate exceedence probability for the general case where a
chemical is released to multiple facilities in an industrial category rather than a single facility.
For this situation, PDM calculates the exceedence probability (using estimated flows) for all
facilities in the Main Facilities File that belong to the industrial category of interest. PDM then
sorts the results and reports the "average case" (the mean exceedence probability) and "high-
end" (the mean of the worst-case 10% exceedence probabilities) of all facilities in the industrial
category.
Previous versions of PDM resorted to using matrix files to decrease computation time.
This is no longer necessary using a contemporary PC, which can perform these calculations for
industrial categories containing 20,000 facilities in 20 seconds or less, depending on the
computer.
Converting from Exceedence Probability to Number of Days per Year Exceeded
Strictly speaking, PDM reports the "probability that the downstream concentration will
exceed the COC on any given day." PDM uses this as a surrogate to estimate the percentage of
release days that the COC will be exceeded. For example, if a release occurs 100 days/year, and
the probability of exceedence is 30 percent, PDM reports that the COC will be exceeded 30 days
(8 percent) of the year.
References
Di Toro, D. M. 1984. Probability Model of Stream Quality Due to Runoff. Journal of
Environmental Engineering, v. 110 n. 3 pp. 607-628.
U.S. Environmental Protection Agency. 1984. Technical Guidance Manual for Performing
Waste Load Allocations. Book VII. Permit Averaging Periods. Washington, DC: Office
of Water Regulations and Standards. EPA 440/4-84-023.
Versar, Inc. 1988. Probabilistic Dilution Model 3. EPA Contract No. 68-02-4254. Task No.
117. May 1988.
W. E. Gates and Associates, Inc. 1982. Estimation of Streamflows and the Reach File.
Prepared for the U.S. Environmental Protection Agency, Office of Water, Monitoring
Branch.
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Appendix D
Issues Pertaining to Inhalation Exposure Estimation Conducted in CEM
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ISSUES PERTAINING TO INHALATION EXPOSURE ESTIMATION CONDUCTED IN CEM
Introduction
This appendix provides further discussion on issues pertaining to the inhalation exposure
modeling algorithms used in CEM. The issues covered are not all inclusive, but elaborate on topics
discussed in Section 3.3 of the EFAST2 Documentation Manual.
1. Inhalation Modeling Duration
In CEM, air releases are modeled for 60 days, regardless of the scenario. This choice,
considered adequate to cover all scenarios, was dictated largely by the "Product Placed in
Environment" scenario, which has a default central-tendency duration of use of 30 days. This
duration was doubled to ensure that time-integrated concentrations and doses, used in LADC/LADD
calculations, would account for the vast majority of the concentration/dose for such an event.
Although the default high-end duration of use for this scenario is 90 days, CEM only uses this
high-end duration for estimation of short-term exposure measures (ADR and Cp), which generally
occur near the beginning of the modeling period. Even in the event that a steady-state condition
were reached, such a condition would occur well before 60 days had elapsed. CEM calculates all
possible ADRs, over the 60-day modeling period, as running 24-hour integrations (i.e., hours 1-24,
2-25, etc.), and then reports the highest of these computed values as the ADR.
The user should also understand that, for scenarios that use a constant emission rate (i.e.,
product placed in environment), while the model may run the exposure and concentration algorithms
for a 60-day period, there may be instances where the emissions will be truncated at or before 60
days. From Section 3.3.7.2, the evaporation time is defined as a function of molecular weight and
vapor pressure. If the evaporation time is less than the 60 days of modeling time, then CEM
assumes that the source is no longer emitting after the evaporation time and sets the emission rate
to zero at that point. For evaporation times longer than 60 days, CEM assumes that the source has
been removed from the environment after 60 days and is no longer emitting.
2. Exposure Events
When estimating exposure dose and concentration, CEM models a single exposure event for
the given scenario, over a period of 60 days, and computes the time-integrated concentration and
dose for that event. The model results can appear somewhat misleading in situations where
exposure events occur more frequently than every 60 days. For instance, in the General Purpose
Cleaning scenario, the default exposure frequency is 300 times per year, indicating that an exposure
event occurs roughly every 1.2 days. This might lead the user to assume that the exposure is
governed by the activity pattern in the Day of Use, plus the first few hours in the Day After Use.
However, this type of approach to modeling the exposure would not account for the cumulative
release of material newly applied and the material still remaining from previous uses. Figure D-l
depicts the situation where an individual is repeatedly exposed to material that is applied before
the material from the previous application has completely evaporated. The dotted line depicts the
cumulative concentration or dose that occurs in these situations. It should be apparent that if CEM
modeled only the duration from the start of an event to the start of the next event, then the exposure
D-2
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concentration or dose would be much less than the cumulative amount under the curve (i.e., the solid
line corresponding to the first event). CEM, however, models a single release until most, if not all,
of the material has evaporated, and takes the product of the time-integrated concentration or dose
per event and the number of events in a year to estimate the exposure concentration or dose for the
year. The exposure estimated using this technique more accurately accounts for overlapping periods
of use and cumulative releases.
0)
»
o
Q
£
O
5
£
0)
O
£
O
o
Time
Figure D-l. Exposure of Overlapping Events
It should be noted that this approach, however, will underestimate the ADR and Cp for cases where
events overlap and the modeled concentration has not returned to zero prior to the start of the next
event. This possibility was recognized in the early days of CEM design, but the chosen approach
was considered a reasonable compromise to avoid excessive modeling and source-code
complexities.
3. Model Usage of Activity Patterns
In modeling a release over 60 days, CEM uses the Day of Use activity pattern from the
exposure event Start Time through midnight of the first day. CEM uses the Day After Use (Non-Use
Day) activity pattern for the remaining time. Therefore, Day of Use activity patterns prior to the
exposure event Start Time do not factor into the exposure estimate. Additionally, the Day After Use
(Non-Use Day) activity pattern plays a fairly significant role in estimating exposure.
It should be noted that CEM is a screening model, and as such has not been designed to
accommodate events where the duration of the event continues into the Day After Use (e.g., an
exposure duration that lasts 4 hours and begins at 10:00 PM). Users who wish to model such an
event are instructed to select a Start Time that allows for the event to be completed during the Day
of Use (e.g., move the Start Time of the previously discussed event to 8:00 PM). Otherwise, the
model will not function properly.
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