# PE5 User\'s Manual

**(P)RZM (E)XAMS MODEL SHELL, VERSION (5).0**

Environmental Fate and Effects Division\
Office of Pesticide Programs\
U.S. Environmental Protection Agency

**Tier 2 Screening Model Shell for Pesticide Aquatic Exposure
Assessment**

Version 5.0 (Nov. 15, 2006)

**Table of Contents**

-   [Introduction to PE5](#introduction-to-pe5)

-   [Installing PE5](#installing-pe5)

-   [Running PE5](#running-pe5)

-   [Bibliography](#bibliography)

## Introduction to PE5

October 22, 2007

The program *PE5.pl* (PE5, PE Version 5.0, dated Nov. 15, 2006) is a
graphical interface (shell) that facilitates placing chemical- and
use-specific input values into the proper positions in PRZM input files
and EXAMS chemical files. The official versions of
[PRZM](http://www.epa.gov/ceampubl/products.htm) (Version 3.12.2, May
12, 2005), [EXAMS](http://www.epa.gov/ceampubl/products.htm) (Version
2.98.04.06, Apr. 25, 2005), and the [PE crop
scenarios](http://www.epa.gov/oppefed1/models/water/index.htm)
associated with PRZM version 3.12.2 should be installed on the hard
drive of your computer before running the PE5 shell. Input parameters
for this program are selected using the latest
[guidance](http://www.epa.gov/oppefed1/models/water/input_guidance2_28_02.htm)
for environmental fate and transport models (USEPA, 2002). Once the
inputs have been entered, the interface creates the necessary input and
run files, calls up PRZM and EXAMS, runs the programs, creates the
output files generated by the DOS programs, and generates two additional
output files. The two output files consist of a time series file and a
summary file that echoes the input data and reports annual maximum and
1-in-10-year estimates. The interface was created using Perl and Tk,
publicly available programming, and requires Perl to run. This guidance
document provides instructions for setting up the shell and models on
your computer, for running the shell, and for retrieving the outputs.
The shell program code can be viewed in any text editor.

PE5 (PE Version 5.0) was implemented in August 2007 along with PRZM
Version 3.12.2, EXAMS Version 2.98.04.06, and the associated PE crop
scenarios as a replacement for PE4 (PE Version 4.01, dated Aug 8, 2003;
developed by Ian Kennedy) and its associated suite of models and
scenarios. The PE5 program, which is used in Tier 2 screening-level
aquatic exposure assessments, was developed in response to user
recommendations for improving the program and for making it consistent
with newer versions of PRZM (Carsel, 1997) and EXAMS (Burns, 2000). The
main differences between the PE4 and PE5 shells are that PE5 includes a
corrected hydrologic length (356.8 meters) for the standard pond, can
correctly read scenarios formatted for PRZM v3.12.2 (including changes
in curve number format), can accept a different application rate at each
application interval for a single run, and can model simultaneous runs
for multiple application dates at a constant application rate.

Using standard crop scenarios, the WQTT conducted an evaluation of the
computer code and model predictions. The results show that PE5 correctly
read the updated input formats and correctly generated PRZM input files
with the data provided. PE5 was also found to function accurately when
compared to command line operation.

## Installing PE5

I. Install Perl.

> A. Perl for Windows is available from ActiveState at
> [[http://www.activestate.com]{.underline}](http://www.activestate.com/).
>
> B. Click on the link for *ActivePerl* (as of this writing it's under
> the drop down window for "language distributions") and follow the
> instructions for downloading the MSI file for Windows, "ActivePerl
> 5.8.8.822" or the appropriate file for your operating system.
>
> C. Once you have downloaded the appropriate file (*e.g.*,
> *ActivePerl-5.8.8.822-MSWin32-x86-280952.msi*), double-click on it and
> follow the instructions to install Perl.
>
> D. After installation, restart your computer to be sure the path to
> the Perl interpreter is set correctly.

II\. Set up a C:\\Models directory, install PRZM and EXAMS, and copy
input files.

> The shell and models look in set folders to call up the programs and
> supporting files (standard scenarios, meteorological files, and EXAMS
> environment files). The official program versions and QA/QC'd files
> for PE5 must be present in these folders. For PE5 to function
> properly, set up your C:\\models directory as follows:
>
> A. Create the folder C:\\Models\\PRZM3\\ and place the PRZM executable
> (*PRZM3122.exe*) within the folder.
>
> B. Create the folder C:\\Models\\EXAMS\\ and place the EXAMS
> executable (*EXAMS.exe*) and the file *exams.daf* within the folder.
>
> C. Create the folder C:\\Models\\Inputs\\ with the following
> subfolders:
>
> PRZMenv (contains the PE crop scenarios (.txt))
>
> EXAMSenv (contains the index reservoir and pond environment files
> (.exv))
>
> Metfiles (contains the weather files (metfiles) (.dvf))
>
> D. Although not necessary, you may want to create a "Runs" folder as a
> way of collecting and organizing your model runs.
>
> 1\. You must save your inputs (using File/Save on the interface's
> menu) before you do a run. This is how you tell the interface in which
> directory to save your output files.
>
> 2\. You can have as many folders for runs as you like.
>
> 3\. It is strongly recommended that you use the "Runs" folder within
> C:\\Models\\ , as PRZM cannot handle long directory strings, which are
> often associated with folders located elsewhere on your hard drive.
>
> 4\. As long as the file *exams.daf* is placed in the
> C:\\Models\\EXAMS\\ folder, it is not necessary to include it in the
> "Runs" folder or any other folders where runs are saved.

E. The folder set up is illustrated below:

+----------+----------+----------+------------+-----------------------+
| F        |          |          |            | Required files        |
| older/su |          |          |            |                       |
| bfolders |          |          |            |                       |
+----------+----------+----------+------------+-----------------------+
| Drive C: |          |          |            |                       |
+----------+----------+----------+------------+-----------------------+
|          | Models   |          |            | *PE5.pl*              |
+----------+----------+----------+------------+-----------------------+
|          |          | PRZM3    |            | *PRZM3122.exe*        |
+----------+----------+----------+------------+-----------------------+
|          |          | EXAMS    |            | *EXAMS.exe*           |
|          |          |          |            |                       |
|          |          |          |            | *exams.daf*^1^        |
+----------+----------+----------+------------+-----------------------+
|          |          | Inputs   | PRZMenv    | \[Standard            |
|          |          |          |            | scenarios\]           |
+----------+----------+----------+------------+-----------------------+
|          |          |          | EXAMSenv   | *ir298.exv*           |
|          |          |          |            |                       |
|          |          |          |            | *pond298.exv*         |
+----------+----------+----------+------------+-----------------------+
|          |          |          | Metfiles   | \[Weather files       |
|          |          |          |            | (metfiles)\]          |
+----------+----------+----------+------------+-----------------------+
|          |          | Runs     |            | (*exams.daf*)^1^      |
+----------+----------+----------+------------+-----------------------+

> ^1^ The *exams.daf* file is required in folders where runs are saved
> only when it is not placed in the C:\\Models\\EXAMS\\ folder.

## Running PE5

I. Open the C:\\Models folder and double-click on the *PE5.pl* icon.
Alternately, you can create a link on your desktop or any other folder
where it is convenient.

> A. A DOS command box labeled "C:\\Perl\\bin\\perl.exe" will open and
> automatically minimize. You can restore this window to watch PRZM and
> EXAMS runs and see some other messages written by *PE5.pl*.
>
> B. The shell labeled "PE5" will open. All inputs and commands are done
> through this interface.

II\. Choose your PE crop scenario, metfile, and EXAMS environment from
the drop down menus found on the upper left side of the screen.

> A. Click on the "PRZM scenario" button for a list of available PE crop
> scenarios (.txt). Move the cursor to highlight the desired scenario
> and click to select.
>
> B. Press the "...from scenario" button and click "OK" in the pop-up
> dialog box to select the metfile (.dvf) associated with your selected
> crop scenario.
>
> 1\. If the suggested metfile is not present in the metfile folder, the
> command box will return the message "Error: Couldn't open".
>
> 2\. Alternatively, you can click on the "Metfile" button, move the
> cursor to highlight the desired metfile, and click to select manually.
>
> C. Click on the "EXAMS environment" button for a list of available
> EXAMS environment (.exv) files.
>
> 1\. Select the index reservoir (ir298.exv) for drinking water
> assessments.
>
> 2\. Select the standard pond (pond298.exv) for ecological exposure
> assessments.
>
> D. Press the "Field Size" button for a list of field size options.
>
> 1\. Select "Reservoir" for the index reservoir.
>
> 2\. Select "EPA Pond" for the standard pond.
>
> 3\. Note: This button will display "Default" or "Pond" when PE5 is
> used to open a .pzr file saved with PE4. "Default" and Pond" are not
> valid field sizes and must be changed before modeling with PE5.

E. Click on the appropriate Runoff Flow option button.

1\. Select "Overall" for the index reservoir.

2\. Select "None" for the standard pond.

> F. Enter the output filename (without extension) using the file-naming
> convention that suits you best.
>
> G. Enter the chemical name, chemical properties, and fate and
> transport parameters in the appropriate boxes.
>
> 1\. Use the current [Input Parameter
> Guidance](http://www.epa.gov/oppefed1/models/water/input_guidance2_28_02.htm)
> to derive the inputs (USEPA, 2002).
>
> 2\. PRZM will use the value entered for K~d~. If there is no value
> entered for K~d~, then PRZM will be set to estimate a value for K~d~
> based on the entered value of K~OC.~ If there is no K~OC~ value, PRZM
> will be told to make estimates based on solubility. The interface will
> pass any values entered for both K~d~ and K~OC~ to EXAMS.
>
> 3\. Degradation rates are entered as half-lives, in days. The script
> converts half-lives to rates (*rate* = -ln(1/2)/*t~1/2~*), unless the
> entered value is zero, in which case the script sets the rate to zero.
>
> H. Click on the "CAM" button to select the appropriate chemical
> application method.

1 = Surface applied (broadcast, not incorporated)

> 2 = Foliar applied, linear application
>
> 3 = (Not used: nonlinear foliar application)
>
> 4 = Incorporated, uniform with depth (default incorporation CAM)
>
> 5 = Incorporated, linearly increasing with depth
>
> 6 = Incorporated, linearly decreasing with depth
>
> 7 = Incorporated, T-Band granular application (use DRFT input variable
> to define fraction of chemical to be applied in top 2 cm, remainder of
> chemical will be uniformly incorporated between 2 cm and user defined
> depth)
>
> 8 = Incorporated entirely into depth specified by user
>
> I. Input an incorporation depth (cm) of 2.0 cm or greater for
> CAM=4,5,6,7,8.
>
> J. Input the application rate (kg a.i./ha), application efficiency
> fraction, spray drift fraction, initial application date (DD-MM), and
> number of applications per year.

K.  Press the "Intervals..." button if more than one application occurs
    per year.

> 1\. Input the interval between applications (days) and any new
> application rate (kg a.i./ha) after the interval in the appropriate
> fields of the pop-up dialog box.
>
> 2\. Note that the application rate field may be left blank for any
> applications that are at the same rate as the initial application.
>
> 3\. Note that application rates must contain six or less characters
> (including the implied 0 for decimals) in order for PRZM to function
> properly (*e.g.*, limit the application rate at 10.333 or 0.0875 kg
> a.i./ha).
>
> L. Click on the "IPSCND" button to select the post-harvest foliar
> pesticide disposition.
>
> 1 = Surface applied
>
> 2 = Completely removed
>
> 3 = Left as is on foliage
>
> M. Press the "Set Hydrolysis\..." button or go to the "Edit" menu and
> choose "Hydrolysis\..." to bring up a dialog box for hydrolysis
> values. The script requires either one value or three in order to
> calculate parameters for EXAMS. You can enter either one
> pH--hydrolysis half-life pair at pH 7 or three pairs at varying pH
> values. If you enter one pair, EXAMS will assume hydrolysis rates do
> not change with pH.
>
> N. The "More PRZM Parameters\..." button is available for PRZM records
> 17, 18 and 26. If you don't have chemical-specific inputs for these
> records (and, in most cases, these data are not available), they will
> be appropriately left to default (or no input) values.
>
> 1\. The foliage pesticide first-order decay and volatilization
> parameters, PLDKRT and PLVKRT, respectively, are rate constants with
> units of d^-1^, rather than half-lives.
>
> 2\. The foliar wash-off extraction coefficient, FEXTRC, is a rate
> constant with units of cm^-1^.

O.  Check the "Write Benthic pore water concentrations" box if you
    desire an output file (.out) that reports summary statistics for
    benthic pore water concentrations.

III\. Save your inputs before running PE5.

A.  The shell runs PRZM and EXAMS from the directory you last saved or
    opened a file from, and if you do not use the open or save commands,
    it will use a default value.

B.  Choose "Save" from the pull-down menu under "File." The dialog box
    will prompt you to select a name and a folder. Save the file in the
    "Runs" folder or any separate folder with a brief directory string.
    The shell gives the saved file a ".pzr" extension, although it will
    open text files with any extension.

IV\. Press the "Run PRZM/EXAMS" button to run the shell once.

A.  The progress of the run can be followed in the command prompt window
    launched when you started the script. The following files will be
    generated in the C:\\Models\\Runs folder:

> *przm3.inp, przm3.run* -- PRZM input and run files
>
> *pz2ex.exa* -- EXAMS command file
>
> *CPRZM31.cnc*, *CPRZM31.hyd*, *CPRZM31.msb* -- PRZM summary outputs
>
> *Filename.zts* -- PRZM time-series outputs
>
> *Filename*\_TS.out -- EXAMS time-series outputs
>
> *Filename.out* -- Standard Table 20 summary outputs

B.  You may want to cut and paste your files into a subdirectory for
    later documentation. Because PRZM calls up some of these files, the
    shell will overwrite them during the next run. As with any PRZM run,
    you should examine the input files closely to make sure the correct
    information was entered.

C.  Use your favorite spreadsheet to open your output file and examine
    the results. The output file is in tab-delimited format and may be
    easier to view in a spreadsheet than a text editor.

V. Alternatively, rather than pressing the "Run PRZM/EXAMS" button to
run PE5 once, you may click on the "MultiRun..." button to
simultaneously model multiple initial application dates for use patterns
of constant application rate.

A.  Type "DATE" in the first row of the pop-up dialog box.

B.  Enter initial application dates (DD-MM) in the rows beneath.

C.  Do not use this feature if application rates other than the initial
    application rate (or a blank entry) are entered in the
    "Intervals..." dialog box.

D.  You may wish to save your "batch" of initial application dates in a
    text editor before running PE5, as the shell does not save data
    entered into the "MultiRun..." dialog box.

E.  *PE5.pl* creates individual output files (.zts, \_TS.out, and .out)
    tied to each initial application date and creates a summary file
    (\_summary.txt) that allows for easy comparison of 1-in-10-year EECs
    for each model run.

F.  While *PE5.pl* has the potential to vary any PRZM input parameter or
    PE crop scenario with the MultiRun function, the initial date of
    application (DATE) is the only variable currently evaluated and
    approved for use in the Office of Pesticide Programs.

VI\. To pull up a saved file for further work, click on "Open" in the
pull-down menu under "File." Navigate to the appropriate folder using
the dialog box and click on the appropriate file to open.

VII\. The pull-down menu under "Edit" includes options to edit any of
the specific PRZM parameters (PRZM env\...) or to edit EXAMS command
lines (EXAMS command). This option is not something that will be needed
for most standard assessments, but is provided for those who may need to
go beyond a routine assessment and are familiar with PRZM and EXAMS.

VIII\. Use the "Quit" button or the "Quit" command under the "File" menu
to quit. While you could also close the shell by clicking on the "X"
button in the upper right corner, the Quit command shuts down both the
shell and the command prompt that was opened at the beginning.

## Bibliography

Burns, L.A. 2000. Exposure Analysis Modeling System (EXAMS).
Environmental Research Laboratory, Office of Research and Development,
U.S. Environmental Protection Agency; Athens, GA.

Carsel R.F., J.C.Imhoff, P.R.Hummel, J.M.Cheplick and J.S.Donigian, Jr.
1997. PRZM-3, A Model for Predicting Pesticide and Nitrogen Fate in Crop
Root and Unsaturated Soil Zones: Users Manual for Release 3.0.
Environmental Research Laboratory, Office of Research and Development,
U.S. Environmental Protection Agency; Athens, GA.

USEPA. 2002. Guidance for Selecting Input Parameters in Modeling the
Environmental Fate and Transport of Pesticides. U.S. Environmental
Protection Agency, Office of Prevention, Pesticides and Toxic
Substances, Office of Pesticide Programs, Environmental Fate and Effects
Division; Feb. 28, 2002. Online at:
<http://www.epa.gov/oppefed1/models/water/input_guidance2_28_02.htm>