Floppy disc included with th;s
item has been shelved separately.
Consult LUIS or ask circulation
staff for assistance.
Interactive Software
for Ranking the Potential
of Organic
Chemicals to Contaminate Groundwater
D. L. Nofziger, P.S.C. Rao and A.G. Hornsby
J COMPUTER SERIES
Central Science
Library
JAN 30 1990
Software in Soil Science u diversity of Florida
101
I F636c etive iol SerlB s / Insitute of Fed d Ariculturl Simc / Univeiwy of Florida / John T. Woat, 0D.n
788
codebk
October 1988
CHEMRANK:
Circular 788
CHENRANK
Interactive Software for
Ranking the Potential of Organic
Chemicals to Contaminate Groundwater
by
D.L. Nofziger, P.S.C. Rao, and A.G. Hornsby
Department of Agronomy
Oklahoma State University
and
Soil Science Department
University of Florida
Copyright 1988, University of Florida
U ". .""
DISCLAIMER
The Board of Regents of the State of Florida, the University of Florida, the
Institute of Food and Agricultural Sciences, and the Florida Cooperative
Extension Service, hereinafter collectively referred to as "UF-IFAS", will not
be liable under any circumstances for the direct or indirect damages incurred
by any individual or entity due to this software or use thereof, including
damages resulting from loss of data, loss of profits, loss of use,
interruption of business, indirect, special, incidental or consequential
damages, even if advised of the possibility of such damage. This limitation of
liability will apply regardless of the form of action, whether in contract or
tort, including negligence.
UF-IFAS does not provide warranties of any kind, expressed or implied,
including but not limited to any warranty of merchantability or fitness for a
particular purpose or use, or warranty against copyright or patent
infringement.
The entire risk as to the quality and performance of the program is with you.
Should the program prove defective, you assume the entire cost of all
necessary servicing, repair, or correction.
The mention of a tradename is solely for illustrative purposes. UF-IFAS does
not hereby endorse any tradename, warrant that a tradename is registered, or
approve a tradename to the exclusion of other tradenames. UF-IFAS does not
give, nor does it imply, permission or license for the use of any tradename.
IF USER DOES NOT AGREE WITH TERNS OF THIS LIMITATION OF LIABILITY, USER SHOULD
CEASE USING THIS SOFTWARE IMMEDIATELY AND RETURN IT TO UF-IFAS. OTHERWISE,
USER AGREES BY THE USE OF THIS SOFTWARE THAT USER IS IN AGREEMENT WITH THE
TERMS OF THIS LIMITATION OF LIABILITY.
CHEMRANK
Interactive Software
for Ranking the Potential of
Chemicals to Contaminate Ground Water
by
D.L. Nofziger1, P.S.C. Rao2, and A.G. Hornsby2
TABLE OF CONTENTS
Introduction . . . . . . . . .
Hardware and Software Requirements . . .
Getting Started . . . . . . .
Operating Conventions . . . . . . .
Software Examples
-Introductory Information . . . . .
-Main Menu . . . . . . . .
-Rank Chemicals . . . . . . .
-Enter, Modify, or Print Soil Data File .
-Enter, Modify, or Print Chemical Data File
-Enter, Modify, or Print Rainfall Data File
-Enter, Modify, or Print Evapotranspiration
-Display File Directory . . . . .
-Select Default Files . . . . . .
-Import ASCII Data Files . . . . .
Description of Ranking Schemes . . . .
Rules Used in Estimating Parameters . . .
References . . . . . . . . .
Appendix
-Use of the Full-Screen Editor . . .
.. .
. .
. .
. .
. .
. .
. .
. 5
. 7
. 8
. 10
. 11
. 14
. 16
. 29
. 32
. 35
. 37
. 38
. 39
. 40
. 45
. 48
. 50
. .
. .
. .
. .
. .
File
. .
* .
. .
. .*
. .
. .
Index . . . . . . . . . . . . . .
. . . . 52
. . . . 55
1. Professor, Department of Agronomy, Oklahoma State University, Stillwater,
OK 74078
2. Professors, Soil Science Department, IFAS, University of Florida,
Gainesville, FL 32611.
INTRODUCTION
Cases of groundwater contamination with trace amounts of various organic
pollutants have been reported in recent years with an increasing frequency and
from a growing list of geographical locations within the U.S.A. Point sources
such as waste-disposal sites and nonpoint sources such as large agricultural
fields have been identified as the sources for groundwater contamination with
industrial organic chemicals (solvents, degreasers, etc.) and various
pesticides. Public concern over adverse health effects from exposure to these
pollutants has brought to the forefront the regulatory need to develop
appropriate guidelines for preventing further contamination of groundwater and
the need to assist in monitoring protocols. To fill this need, a large number
of comprehensive simulation models have been developed for predicting the
environmental behavior of organic chemicals in soils and groundwater. The
models require extensive input data in terms of the properties of the soils,
crops, climate, geology, and organic chemicals. Such extensive
characterization data sets are often unavailable for running the comprehensive
models on a site-specific basis.
To overcome this limitation of the more sophisticated models, a number of
"screening" models have been developed that permit a ranking of the sites and
chemicals in terms of their relative potential for groundwater contamination.
These models are NOT intended to predict the extent of groundwater
contamination at a specific site by a group of chemicals. Rather, a relative
ranking of the sites and chemicals is provided for an initial screening and
prioritization among a large number of sites or chemicals to be evaluated. The
number of combinations and. sites is much too large for site-specific
investigations or monitoring to be either practical or economically feasible.
The screening models permit attention and resources to be focused on a subset
of sites or chemicals which have the greatest potential for groundwater
contamination. Among the methods available for ranking several sites is the
DRASTIC scheme, developed by Aller et al. (1985), which assigns numerical
ratings to sites on the basis of their geohydrologic settings and the
likeliness for groundwater contamination.
The CHEMRANK software described here utilizes four schemes for screening a
group of organic chemicals in terms of their relative likelihood to leach past
a specified soil depth and intrude into groundwater. Two of these schemes are
based on the rates at which these chemicals might leach through the
unsaturated (vadose) zone, while two others use the relative rates of mobility
and degradation of the chemicals within the vadose zone as the basis for the
ranking. The potential for groundwater contamination is assumed to be greater
for chemicals that leach rapidly through the soil profile and when larger
fractions of the applied chemical leach past a specified soil depth.
Of the four schemes presented, two utilize simple ranking indices developed by
Rao et al. (1985) which assume that steady water-flow conditions prevail.
While this assumption is perhaps too simplistic for "real world" scenarios
involving transient water-flow conditions, the ranking schemes do provide
reasonable rankings of the selected group of chemicals (see Rao et al., 1985).
Two other schemes use the simulation model CMLS, developed by Nofziger and
Hornsby (1986, 1987), to calculate the time required to reach a given soil
depth and the amount of chemical leaching past a specified soil depth. All
four ranking schemes utilize depth-dependent soil properties, if they are
available. The CMLS model calculates water and chemical movement on a daily
basis using data files containing daily evapotranspiration and water inputs
(i.e., water infiltration resulting from irrigation or rainfall). Thus, the
two schemes based on the CMLS model might be preferred, but the input data
requirements are much greater than those of the two simpler schemes.
Three key environmental-fate properties of the chemicals needed in the ranking
schemes are sorption partition coefficient, Henry's constant, and degradation
half-life. A data file containing these parameter values, compiled on the
basis of published literature for a number of organic chemicals, is provided
in this software. While site-specific values are preferred, several indirect
methods for estimating the sorption coefficient values have also been
incorporated, in the event that the user does not know these values for
specific chemicals. A data file for the required soil properties for several
Florida soils is also included; these data are based on the joint efforts of
the University of Florida (UF) and the Soil Conservation Service (SCS) in
carrying out a soil characterization program. Similar data sets may be found
in SCS reports published for other states. Sample data files for daily
evapotranspiration and water inputs are provided. Such data filet for a
specific site need to be provided by the user if the two ranking schemes based
on CMLS are to be used. Otherwise, an estimate of the steady water flux within
the vadose zone is required; this may be estimated as the annual groundwater
recharge rate or other similar values for the region of interest. The software
permits the user to enter and modify the data files for soils, chemicals, and
weather.
This manual describes the use of an interactive microcomputer model, CHEMRANK,
which was written to determine the four indices described above for estimating
the potential of different organic chemicals to contaminate groundwater. The
software includes data management features for entering, displaying, and
manipulating soil data, chemical data, and daily infiltration and
evapotranspiration amounts in data files. If needed, chemical properties
stored in the chemical file are combined using a set of rules to estimate the
unknown values of parameters which are needed. The manual describes the
required computer hardware and software for using this model, procedures for
using the software, and operating conventions. It then illustrates the use of
the software. Finally, each index and the assumptions inherent in it are
described.
HARDWARE AND SOFTWARE REQUIREMENTS
This software requires an IBM3 PC, XT, or AT or a compatible computer with at
least 512K bytes of random access memory and two floppy disks or one floppy
disk and a fixed disk. A color/graphics or enhanced graphics board and a
compatible monitor are essential to fully utilize this software. A printer is
useful but is not essential. If an 8087 or 80287 math coprocessor is present,
it will dramatically speed up computations.
The operating system must be PC-DOS or MS-DOS 2.0 or a
ANSI.SYS device driver from your DOS diskette must
GRAPHICS.COM file must be executed to obtain copies of the
by pressing the
and keys.
later version. The
be installed. The
graphs on a printer
3. IBM is a registered trademark of International Business Machines, Inc.
GETTING STARTED
Files on Distribution Diskette: This software is distributed on a single
floppy disk which contains the following 6 files:
This is the executable program file.
This data file contains the soil data needed.
This data file contains the chemical data required and
those used for estimating the required parameters.
This file contains an example of "effective" rainfall data
for 1983 to 1986.
This file contains daily evapotranspiration data for 1983
to 1986.
This text file contains the latest information about the
software.
Making a Working Copy: The first step is to make a working copy of the
software on the distribution diskette. If the software is to be used on a
floppy disk system, you will need to format a floppy diskette and copy the
software. The FORMAT command of DOS may be used to format the working disk.
The following steps can be used to make a working copy on a floppy diskette:
1. Place the DOS diskette in default drive A:
2. Place a new diskette in drive B:
3. Format the new diskette using the command FORMAT B:/S
4. Copy the GRAPHICS.COM file from your DOS diskette to the new diskette.
5. Copy the ANSI.SYS file from the DOS diskette to the new diskette.
6. Copy the entire contents of the distribution diskette to the working
diskette.
7. Create a CONFIG.SYS file containing at least the entry DEVICE-ANSI.SYS
on one line and store this file on the working disk. When the system
boots up with this diskette, this file will cause the system to load the
ANSI device driver into memory.
8. You may want to create an AUTOEXEC.BAT file with the entry GRAPHICS on
one line. When the system boots up, it will execute this file
automatically. This will execute the GRAPHICS.COM program so screen
dumps of graphs can be obtained using the - keys.
9. Place the distribution diskette in a safe place.
If the software will be used on a fixed disk, you will likely want to make a
new subdirectory for this application. The files should then be copied to this
subdirectory on the fixed disk. The distribution diskette should be stored in
a safe place. You will need to make sure that the CONFIG.SYS file used on
boot-up contains the line DEVICE-ANSI.SYS and that the GRAPHICS command is
executed before executing this program.
Program Execution: To execute CHEMRANK, place the working diskette in the
default disk drive. Then enter CHEMRANK to execute the program.
NOTE: As you increase the size and number of your data files, the program and
data may not fit on one diskette. It may be most convenient to place the disk
with all the data files in the default disk drive. The program can then be
executed from another drive.
OPERATING CONVENTIONS
The following conventions are used throughout this software:
1. Program Interruption: The user can interrupt the program by pressing the
key. The key can also be used to skip over introductory
material presented at the beginning of the program.
2. Keyboard Inputs: Single-character entries such as menu selections and
responses to yes/no questions are made by pressing only the desired key.
The key is not required.
3. File Names: File names may be any legal MS-DOS or PC-DOS file
identifier, including the disk drive and path. File extensions are not
needed. File extensions are ignored, except when included in the names
of text files.
4. Using the Parameter Editor: To enable the user to easily modify
parameters in screens such as those shown in option A, Figures 5 and 6,
an editor is included in the software, When the information initially
appears on the screen, values will be present for most parameters. These
values will be default values the first time the option is used. If the
option is used repeatedly, the previous entries will be present. The
user may then use the cursor keys to move the cursor up or down on the
screen to make any desired changes. The and keys
will move the cursor up or down one line, respectively. The key
will move the cursor to the top line. The key will move the cursor
to the bottom line. When all the changes on a particular screen have
been made, the key should be pressed to continue execution of the
option. The key may be pressed at any time to abort the option.
Brief help messages may be obtained by pressing the key.
INTRODUCTORY INFORMATION
CHEMRANK
Version 2.5
by
D.L. Nofziger, P.S.C. Rao, and A.G. Hornsby
Institute
Institute
Department of Agronomy
Oklahoma State University
and
Soil Science Department
of Food and Agricultural Sciences
University of Florida
Copyright 1988
by
University of Florida
of Food and Agricultural Sciences
This interactive software is designed to provide multiple schemes
for ranking the potential for organic chemicals to leach into
groundwater for different soil and environmental conditions.
Figure 1. Purpose of the program as shown on screen 1.
Figure 1 is the first screen of the program. It describes the purpose of the
software. Figures 2 and 3 describe the four ranking schemes which can be used
in this software.
Four ranking schemes are supported by this software. They differ in the
data requirements, ranking criteria, and assumptions.
1. Retardation Factor (RF):
This scheme, used previously by Rao et al. (1985) and Jury et al.
(1983, 1984a, b), ranks the chosen organic chemicals on the basis of
their relative rates of movement through the selected soil profile. It
is assumed that steady water-flow conditions prevail. Chemicals that
move rapidly are assumed to have a greater potential to contaminate
groundwater.
This scheme requires values for the soil bulk density, soil-water
contents at saturation and at 0.1 bar tension, and sorption coefficient
for each chemical for each soil horizon along with Henry's constant for
each chemical.
2. Attenuation Factor (AF):
This scheme was developed by Rao et al. (1985) to rank chemicals
using as an index the fraction of the applied amount that is likely to
leach past a specified soil depth. In determining this fraction, both
the rates of leaching and degradation of the chemical are used. In
ranking the selected chemicals, it is assumed that the larger the
fraction of chemical leaching past the specified depth, the greater is
the potential for groundwater contamination. As in the RF scheme, it is
assumed that steady water-flow exists.
This scheme requires the value for the degradation half-life for each
chemical in each of the soil horizons, in addition to the parameters
listed above for RF.
Figure 2. Explanation of ranking by
factor, as shown on screen 2.
retardation factor and attenuation
Ranking Schemes continued:
3. Travel Time from CMLS:
The basis for ranking the selected group of chemicals by this scheme
is similar in concept to that used for the RF scheme, in that the
relative rates of leaching are used. Thus, chemicals that have shorter
travel times to the specified depth would have a greater potential to
contaminate groundwater. Unlike the RF scheme, however, chemical
leaching is computed using the CMLS model (Nofziger and Hornsby, 1986)
utilizing daily rainfall and evapotranspiration data. This model allows
for depth variations in soil properties.
This scheme requires values of water content at 0.1 and 15 bars, of
bulk density, and of organic carbon content for each soil horizon.
Sorption partition coefficients for each chemical, crop rooting depth,
daily water inputs(rainfall or irrigation), and daily evapotranspiration
rates are also needed.
4. Mass Emissions from CMLS:
Ranking by this scheme is similar to that for the AF scheme, except
that the fraction of the applied chemical leaching past the specified
soil depth is computed using the CMLS model of Nofziger and Hornsby
(1986).
This method requires the values for the degradation half-life for
each chemical in addition to the information needed for Scheme 3 above.
Figure 3. Explanation of ranking by travel time and mass emissions from the
CMLS model, as shown on screen 3.
MAIN MENU
CHEMRANK
Version 2.5
by
D.L. Nofziger, P.S.C. Rao, and A.G. Hornsby
Copyright 1988
OPTIONS :
A.
B.
C.
D.
E.
F.
G.
I.
Q.
Desired Option ? A
Rank Chemicals
Enter, Modify, or Print Soil Data File
Enter, Modify, or Print Chemical Data File
Enter, Modify, or Print Rainfall Data File
Enter, Modify, or Print Evapotranspiration Data File
Display File Directory
Select Default File
Import ASCII Data Files
Quit. Terminate Program and Return to DOS
Figure 4. Main menu of the program.
Figure 4 contains the main menu of this program. Options are selected by
entering the letter corresponding to the option desired. In this example
option A was selected. A brief description of each option is given below. The
use of each option is illustrated on the following pages.
Rank Chemicals
This option is used to rank a group of chemicals on the
basis of one or more of the schemes provided. Results of
the rankings can be displayed on the screen or printer in
tabular or graphical form. Tabular results may be stored
in text files for use in reports and other documents.
Enter, Modify, or Print Soil Data File
The required data for each soil must be stored in a data
file. This option permits the user to enter new soil
information into the file, to modify existing information,
to display information from the file on the screen or
printer, or to convert the file to a text file for use
with other software.
Enter, Modify, or
Enter, Modify, or
Enter, Modify, or
Print Chemical Data File
Required information for each chemical may be stored in a
file for repeated use in simulations. This option enables
the user to enter new chemical data into the file, to
modify existing chemical data, to display chemical data
from the file on the screen or printer, or to convert the
chemical data into a text file for use with other
software.
Print Rainfall Data File
Ranking chemicals on the basis of travel time and mass
emissions using the CMLS model requires daily records of
the amount of rainfall or irrigation water entering the
soil. This option permits the user to enter, to modify,
and to display these data for the site and time period (15
years or less) of interest. These data can be converted to
text files for use with other software.
Print Evapotranspiration Data File
The ranking schemes based on CMLS require daily records of
water lost from the soil by evapotranspiration, or the sum
of the amounts lost by evaporation from the soil surface
and that lost by transpiration through the growing plant.
This option enables the user to enter, to modify, and to
display these data. These data can be converted to text
files for use with other software.
Display File Directory
This option simply displays the file directory for a disk
drive, subdirectory, and mask entered by the user.
Select Default Files
One chemical file can contain data for 400 chemicals. The
soil file can contain data for 50 to 1000 soils. If data
for a larger number of soils or chemicals need to be
stored, several files may be used. This option permits
the user to specify the soil and chemical files to be used
in the ranking option.
Import ASCII Data Files
This option permits the user to read soil, chemical,
"effective" rainfall, and evapotranspiration files stored
as ASCII text. The files are converted and stored in the
forms used in this software. This is especially useful for
rainfall and evapotranspiration files created and used in
CMIS (Nofziger and Hornsby, 1985).
Quit. Terminate Program and Return to DOS
This option is used to end the program and return control
to the disk operating system.
RANK CHEMICALS
Ranking chemicals requires the user to select the ranking schemes of interest,
to select the soil and several other site parameters, and to specify the
chemicals to be included in the ranking and their properties. These are
carried out in this software by using three screens. The ranking schemes of
interest are selected by entering Y or N for each scheme as shown in Figure 5.
Select Ranking Schemes
Rank chemicals by
Retardation Factor (Y,N) :Y
Attenuation Factor (Y,N) :Y
Travel Time from CMLS (Y,N) :Y
Mass Emissions from CMLS (Y,N) :Y
Use cursor keys to position cursor. Then make desired changes.
Press when finished entering all information.
Press for help. Press to abort this option.
Figure 5. Selecting the ranking schemes to be used.
Site Parameters
Soil identifier
Application depth (m)
Control depth (m)
Recharge rate (mm/day)
Rooting depth (m)
Rainfall file
Evapotranspiration file
Application date
:S27-8-(1-6)
:0.00
:1.00
:10.0
:0.30
:LOCAL83.R
:LOCAL83.ET
:1/1/83
Use cursor keys to position cursor. Then make desired changes.
Press when finished entering all information.
Press for help. Press to abort this option.
Selecting site parameters of interest.
Figure 6.
The site parameters are specified using the screen shown in Figure 6. In this
case, all of the site parameters are required for the schemes selected. If any
parameters are not needed for the schemes selected, the system will skip over
them. The following is a description of each parameter.
Soil identifier
Application depth
Control depth
Recharge rate
Rooting depth
Rainfall file
Evapotranspiration
Application date
This is a unique series of characters and numbers which
identify the soil of interest. This identifier must match
the identification code for the soil in the soil data
file. When this is entered, the system searches the soil
data file for that soil. An error message is given if the
soil is not found in the file. The user must then enter
another identifier.
This is the soil depth to which the chemical is
incorporated at application. For example, for surface-
applied chemicals this depth is zero.
This is the depth of concern in the soil. Rankings are
based on the time required to reach this depth or on the
amount of chemical reaching this depth. For example, the
maximum depth of crop rooting can be used.
This is the average daily amount of water moving downward
through the soil. This parameter is needed only when
calculating the attenuation factor index (scheme 2). The
recharge rate is assumed to be a constant at all depths.
This is the depth to which water is removed in this soil
by evapotranspiration. This parameter is used for ranking
by travel time and mass emissions using CMLS (schemes 3
and 4).
This is the file identifier for the file containing daily
"effective" rainfall or daily infiltration rates.
file
This is the file identifier for the file containing daily
evapotranspiration rates.
This is the date on which the chemicals were applied. The
CMLS model begins using rainfall and evapotranspiration
data on this date.
Chemical Parameters
Chemical of interest (CAS No. or Name) :NONE
Henry's constant, Kh :.
Horizon Maximum Depth Partition Coefficient Half-Life
(m) Kd, (ml/g soil) (days)
1 0.10
2 0.20
3 0.53
4 1.07
5 1.22
6 2.03
Fl-HELP; F2-Entering Columns; F5-Copy Value Above;
Esc-Abort; F9-Rank Chemical; FlO-Rank Chemical & Output Results;
Figure 7. Selecting chemicals to be ranked.
Chemicals to be ranked are specified in the screen shown in Figure 7.
Chemicals are specified using the CAS number or common name. When the chemical
is entered, the chemical is located in the chemical data file. Values for
Henry's constant (Kh), organic-carbon partition coefficient (Koc), and half-
life (tl/2) are found in the file or they are evaluated using the rules
described later in this manual. The partition coefficient (Kd), is calculated
for each horizon by means of the equation Kd KOC'OC, where OC is the
fractional organic-carbon content for that soil horizon. The estimates of the
parameters from the file are then displayed on the screen for each soil
horizon (see Figure 8). If the user has specific values for this site, those
values may then be entered from the keyboard. When the values on the screen
are to be used, the user may press the key to calculate the indices for
this chemical. The calculated indices are displayed as soon as they are
determined, as shown in Figure 9. When the user presses any key, the screen
shown in Figure 7 is again displayed. The user may then specify the next
chemical to be ranked. This process of selecting chemicals continues until the
user is finished and presses the key. Pressing the key aborts the
ranking option and returns control to the main menu.
Chemical Parameters
Chemical of interest (CAS No. or Name) :MALATHION
Henry's constant :5.000E-006
Horizon Maximum Depth
(m)
1 0.10
2 0.20
3 0.53
4 1.07
5 1.22
6 2.03
Partition Coefficient
Kd, (ml/g soil)
9.845
7.518
1.611
1.074
0.716
0.358
Fl-HELP;
Esc-Abort;
F2-Entering Columns;
F9-Rank Chemical;
F5-Copy Value Above;
FlO-Rank Chemical & Output Results;
Figure 8. Chemical selection screen after the name of the chemical was
entered and values of the parameters were determined.
I
Chemical Parameters
Chemical of interest (CAS No. or Name) :MALATHION
Henry's constant :5.000E-006
Horizon Maximum Depth
(m)
1 0.10
2 0.20
3 0.53
4 1.07
5 1.22
6 2.03
Partition Coefficient
Kd, (ml/g soil)
9.845
7.518
1.611
1.074
0.716
0.358
Number of chemicals ranked is 1.
Chemical : MALATHION
Retardation Factor 73.2988
Attenuation Factor 0.0000
Travel Time 1162 days (depth = 1.03 m)
Mass Emissions 0.0000
Press Any Key To Continue
Figure 9. Chemical selection screen with calculated ranking indices which
are obtained after the user presses the or key.
Half-Life
(days)
1
1
1
1
1
Half-Life
(days)
1
1
1
1
1
1
Output Options
Display Ranking Sequence table (Y,N) :Y
Display Retardation Factor table (Y,N) :Y
Display Attenuation Factor table (Y,N) :Y
Display Travel Time table (Y,N) :Y
Display Travel Time bar graph (Y,N) :Y
Display Mass Emissions table (Y,N) :Y
Display Mass Emissions bar graph (Y,N) :Y
Display Input Parameters used (Y,N) :Y
Output device or file :SCREEN
Use cursor keys to position cursor. Then make desired changes.
Press when finished entering all information.
Press for help. Press to abort this option.
Figure 10. Screen for selecting desired outputs and output device
After the user has entered all of the chemicals to be included in this ranking
process and has pressed the key to end selection of chemicals, the
screen shown in Figure 10 is displayed to enable the user to select the output
tables and graphs desired. The output options are described and illustrated on
the following pages. The last entry on this screen enables the user to select
the desired output device or file. Tabular output can be displayed on the
SCREEN or PRINTER by entering the desired device. This output can also be
stored in ASCII text files by entering a legal DOS file identifier. After the
desired outputs have been displayed and the user has pressed the key,
the selected tables and graphs are displayed. The program then returns to this
screen to enable the user to select different options or a different device.
When all outputs for the current list of chemicals have been obtained, the
user may press to return to the chemical-selection screen (Figure 7).
The user may then select additional chemicals to be added to the current list
or the user may press the key again to return to the main menu.
The outputs available include:
1. The ranking sequence table is a summary listing each chemical entered
along with a number representing the ranking of the chemical for each
scheme selected. The closer the ranking is to 1 the greater the
potential for groundwater contamination by the chemical as determined
using that ranking scheme. Table 1 illustrates the summary ranking table
for a group of chemicals.
2. The retardation factor table lists the chemicals in sequence from most
mobile to least mobile based on the retardation factor ranking (Table
2). The numerical value for the retardation factor index is also listed
for comparison among chemicals. Retardation factors range from 1 to
infinity, with chemicals with values nearest 1 being most rapidly
transported through the soil.
3. The attenuation factor table lists the chemicals in sequence from the
most hazardous to the least hazardous based on the estimated amount of
the chemical passing the control depth (Table 3). The numerical value
expressing the fraction of the chemical passing the control depth is
also displayed for each chemical. These numerical values range from 0 to
1, with chemicals with larger values being more hazardous.
4. The travel time table lists the chemicals based on the travel time
required to move from the application depth to the control depth (Table
4). Travel times are also displayed for each chemical. Chemicals with
smaller travel times are considered more dangerous than those with
longer travel times in this scheme. These travel times are calculated
using the model of CMLS, which requires effective rainfall files for
each day. If the data in the file are insufficient for the chemical to
reach the control depth, the travel time listed in the table is the
maximum number of days of rainfall data preceded by the "greater than"
(>) sign. This is a conservative estimate of the travel time. If more
rainfall data were available the ranking sequence could be significantly
altered.
5. The travel time bar graph displays a bar graph for the chemicals ranked.
The heights of the bars represent the travel times for the chemicals.
The screen, illustrated in Figure 11, also includes a list of chemicals
and their associated ranking so the user can identify each bar with a
particular chemical. If the number of chemicals ranked exceeds the
number which can be displayed on the screen at one time, the user may
use the cursor keys to scroll the list up or down. The user may also
make a copy of the screen to the printer by pressing the .
6. The mass emissions table displays the chemicals based on the relative
amount of each chemical passing the control depth as determined using
the CMLS model. The relative amount of chemical remaining is also
displayed (Table 5). This relative amount ranges rom 0 to 1, with
chemicals having larger mass emissions considered more dangerous in this
scheme. If the effective rainfall file does not contain sufficient data
to result in movement to the control depth, the "less than" (<) symbol
precedes the displayed number since the actual amount will be less than
that calculated. The order of the chemicals in the list might be changed
significantly if more rainfall data were available.
7. The mass emissions bar graph is similar to the travel time bar graph
except that the heights of the vertical bars represent the calculated
mass emissions. This is illustrated in Figure 12. Note that the vertical
axis is displayed on a logarithmic scale. The cursor keys may be used to
scroll through the chemical names if the chemicals cannot be displayed
on the screen at one time. The keys can be used to obtain
copies of the screen on a printer.
8. The table of input parameters displays the soil, chemical, and
environmental factors used in the ranking schemes. This is illustrated
in Table 6. Included in the table for each chemical are indicators of
the source of the chemical parameters. These indicators are given by the
letter R followed by a number. RO is used to indicate that the data were
entered from the keyboard. R1, R2, R3, ... refer to rules listed in the
Appendix for determining the parameters.
Table 1. Ranking of chemicals for all schemes selected.
CAS Number
Common Name
Retardation Attenuation
Factor Factor
Travel
Time
330-54-1
DIURON
1563-66-21 2 2
CARBOFURAN
116-06-3 1 3
ALDICARB
1912-24-9 3 4
ATRAZINE
1918-00-9 4 5
DICAMBA
121-75-5 6 6
MALATHION
Table 2. Ranking of chemicals based on retardation factor
Rank CAS Number Chemical Name
116-06-3
1563-66-21
1912-24-9
1918-00-9
330-54-1
121-75-5
ALDICARB
CARBOFURAN
ATRAZINE
DICAMBA
DIURON
MALATHION
Mass
Emissions
1.7E+000
2.0E+000
7.5E+000
9.2E+000
1.4E+001
7.3E+001
Table 3. Ranking of chemicals based on attenuation factor.
Rank CAS Number Chemical Name
330-54-1
1563-66-21
116-06-3
1912-24-9
1918-00-9
121-75-5
DIURON
CARBOFURAN
ALDICARB
ATRAZINE
DICAMBA
MALATHION
Table 4. Ranking of chemicals based on travel time.
Rank CAS Number
Chemical Name
Travel
Time (days)
116-06-3
1563-66-21
1912-24-9
1918-00-9
330-54-1
121-75-5
ALDICARB
CARBOFURAN
ATRAZINE
DICAMBA
DIURON
MALATHION
Table 5. Ranking of chemicals based on mass emissions.
Rank CAS Number Chemical Name
330-54-1
1563-66-21
116-06-3
1912-24-9
1918-00-9
121-75-5
DIURON
CARBOFURAN
ALDICARB
ATRAZINE
DICAMBA
MALATHION
8.4E-001
8.3E-001
7.8E-001
5.5E-001
7.8E-002
O.OE+000
33
33
86
105
214
1162
Mass
Emissions
6.36E-001
5.80E-001
4.15E-001
2.89E-001
5.52E-003
O.OOE+000
Table 6. Summary of input parameters.
SOIL DATA
Soil name: TAVARES FS
Horizon Depth Organic Carbon
(m) (%)
1 0.10 0.55
2 0.20 0.42
3 0.53 0.09
4 1.07 0.06
5 1.22 0.04
6 2.03 0.02
Soil identification: S27-8-(1-6)
Bulk Density -- Water Content (% by vol) at --
(g/cc) -.01 MPa -1.5 MPa Saturation
1.42 6.5 1.3 47.4
1.40 7.2 1.5 48.1
1.50 5.2 0.8 44.4
1.56 5.4 0.7 42.2
1.56 6.1 0.8 42.2
1.58 11.9 1.0 41.5
SITE INFORMATION
Application depth:
Control depth:
Recharge rate:
Rooting depth:.
Rainfall file:
Evapotranspiration
Application date:
0.00 meters
1.00 meters
10.0 mm/day
0.30 meters
LOCAL83.R
file: LOCAL83.ET
1/1/83
CHEMICAL DATA
Chemical name: MALATHION
CAS number: 121-75-5
Henry's constant, Kh
Horizon Maximum Depth
(m)
1 0.10
2 0.20
3 0.53
4 1.07
5 1.22
6 2.03
Source:
: 5.000E-006
Partition Coefficient
Kd, (ml/g soil)
9.845E+000
7.518E+000
1.611E+000
1.074E+000
7.160E-001
3.580E-001
R1
Source R1
Half Life
(days)
1.0
1.0
1.0
1.0
1.0
1.0
R1
Table 6. Continued.
CHEMICAL DATA
Chemical name: DIURON
CAS number: 330-54-1
Henry's constant, Kh :
Horizon Maximum Depth
(m)
1 0.10
2 0.20
3 0.53
4 1.07
5 1.22
6 2.03
Source:
6.000E-007
Partition Coefficient
Kd, (ml/g soil)
1.804E+000
1.378E+000
2.952E-001
1.968E-001
1.312E-001
6.560E-002
R1
CHEMICAL DATA
Chemical name: ALDICARB
CAS number: 116-06-3
Henry's constant, Kh
Horizon Maximum Depth
(m)
1 0.10
2 0.20
3 0.53
4 1.07
5 1.22
6 2.03
Source:
: 2.000E-009
Partition Coefficient
Kd, (ml/g soil)
9.350E-002
7.140E-002
1.530E-002
1.020E-002
6.800E-003
3.400E-003
R1
CHEMICAL DATA
Chemical name: CARBOFURAN
CAS number: 1563-66-21
Henry's constant, Kh : 5.000E-005
Horizon Maximum Depth
(m)
1 0.10
2 0.20
3 0.53
4 1.07
5 1.22
6 2.03
Source:
Partition Coefficient
Kd, (ml/g soil)
1.402E-001
1.071E-001
2.295E-002
1.530E-002
1.020E-002
5.100E-003
RI
Source RI
Half Life
(days)
328.0
328.0
328.0
328.0
328.0
328.0
R1
Source R1
Half Life
(days)
26.0
26.0
26.0
26.0
26.0
26.0
R1
Source R1
Half Life
(days)
42.0
42.0
42.0
42.0
42.0
42.0
RI
Table 6. Continued.
CHEMICAL DATA
Chemical name: ATRAZINE
CAS number: 1912-24-9
Henry's constant, Kh :
Horizon Maximum Depth
(m)
1 0.10
2 0.20
3 0.53
4 1.07
5 1.22
6 2.03
Source:
1.OOOE-007
Partition Coefficient
Kd, (ml/g soil)
8.800E-001
6.720E-001
1.440E-001
9.600E-002
6.400E-002
3.200E-002
R1
CHEMICAL DATA
Chemical name: DICAMBA
CAS number: 1918-00-9
Henry's constant, Kh :
Horizon Maximum Depth
(m)
1 0.10
2 0.20
3 0.53
4 1.07
5 1.22
6 2.03
Source:
2.000E-005
Partition Coefficient
Kd, (ml/g soil)
1.111E+000
8.484E-001
1.818E-001
1.212E-001
8.080E-002
4.040E-002
R1
Source R1
Half Life
(days)
48.0
48.0
48.0
48.0
48.0
48.0
R1
Source RI
Half Life
(days)
14.0
14.0
14.0
14.0
14.0
14.0
R1
N ,
z
M
I-U)
1500
Rank Trave Tie CTiM. NM
I ALC
3 11 AThRA
4 5 DICA
5 14
6 116m 4020ON
Figure 11. Bar graphs of travel times for the chemicals ranked.
- 11-12 *
S 1-18
1E-24 -
1E-3B L
80 1 2 3
Rank Mass Emissions Chemioal Nas
1 6.62 el DIUROM
2 5.8 -e 1 CARBOFURAN
3 4.49 1 ALDICAR
4 2888 -810 ATRA2N1E
5 524E-003 DICAMBA
6 8.080E+100 MALATHION
RUNNING
1 U 9 1u
Figure 12. Bar graphs of mass emissions for the chemicals ranked. Note the
vertical axis is on a logarithmetic scale.
ENTER, MODIFY, OR PRINT SOIL DATA FILE
This option is used to enter the required soil parameters into a file, to
modify data entered previously, and to print the contents of the file on the
screen or a printer. The following parameters are required for each soil:
Soil name This is a descriptive name of the soil. It may be up to 20
characters in length.
Soil identifier This is the sequence of characters which will be used in
the ranking option to select this soil. Therefore, it must
be different for each soil. It may be up to 20 characters
in length, but shorter identifiers are recommended.
Depth of the bottom of each horizon
The distance from the soil surface to the bottom of each
horizon is required to define the soil horizon limits so
the soil properties of that horizon are used only for the
proper depths. If the model predicts that a chemical will
move below the depth of the deepest characterized horizon,
the soil properties are assumed to be those of the deepest
horizon.
Organic carbon content of each horizon
This value, expressed as' a weight percent, is used to
obtain the partition coefficient for the soil horizon of
interest from the partition coefficient for the chemical
normalized to soil organic carbon. If the organic carbon
content of the soil horizon is not known it can be
estimated by multiplying the organic matter content of the
horizon by 0.4.
Bulk density of each horizon
This is the mass of dry soil per unit volume of soil.
Since most agricultural data bases represent bulk density
in g/cm3, these units are used here. Unit weight (lb/ft3)
may be converted to g/cm3 by multiplying by 0.016.
Soil-water content at a matric potential of -0.01 MPa (-0.1 bars)
This is the volumetric soil-water content (expressed as a
percent) at the matric potential specified. This value is
used as an estimate of "field capacity" for the soil. It
is required for each horizon in the profile. Note: The
water content at a matric potential of -0.033 MPa (-0.33
bars) may be entered in lieu of the water content at -0.01
MPa if the user deems this a more appropriate estimate of
the "field capacity" of the soil. However, the program
will indicate that the value entered represents the water
content at -0.01 MPa.
Soil-water content at a matric potential of -1.5 MPa (-15 bars)
This is the volumetric soil-water content (expressed as a
percent) at the matric potential specified. This value is
used as an estimate of "permanent wilting point" for the
soil. It is required for each horizon in the profile.
Soil-water content at saturation
This is the soil-volumetric water content (expressed as a
percent) when all the soil pores are water-filled.
Figure 13 illustrates the first screen requiring user input after selecting
this option. Here, the user enters the soil file name to be used and option
desired. In this case the edit option was selected. This option is illustrated
on the following pages. Option 'P' displays the contents of the file on the
printer; option 'S' displays the contents of the file on the screen; and
option 'F' converts the file into an ASCII text file for use in other
programs.
When option 'F' is chosen, the user is prompted for the name of the text file.
If that file does not exist, it is created. If it exists, the output is
appended to the end of the file. The user is also asked if the file should be
output with titles for each field. If titles are wanted the text file will be
similar to the screen listing. If not, only data are output with one record
per line and values for fields within a record separated by commas.
Enter Name of File to be Used [Default is SOIL.S]:SOIL
OPTIONS:
E. Enter or edit data in file
P. Print data in file
S. Display data on screen
F. Convert data to a text file
Desired Option: E
Figure 13. Selecting units, soil file, and edit option.
Figure 14 illustrates the use of the full-screen editor for entering soil
data. Each line on the screen represents a particular horizon. In this case,
several columns of data exist to the right of the edge of the screen. The user
may use the cursor keys to move around on the screen. The contents of the
screen are shifted horizontally to enable the user to enter or edit any
parameter for each horizon. The cursor and function keys used in this editor
are described in the Appendix.
Record Horizon No.
Soil Name
ADAMSVILLE I
ADAMSVILLE I
ADAMSVILLE I
ADAMSVILLE I
ADAMSVILLE I
ADAMSVILLE I
ADAMSVILLE I
ADAMSVILLE I
ADAMSVILLE I
ADAMSVILLE I
ALBANY LS
ALBANY LS
ALBANY LS
ALBANY LS
ALBANY LS
ALBANY LS
ALBANY LS
ALBANY SAND
ALBANY SAND
ALBANY SAND
Soil Identifier
SAND
SAND
SAND
SAND
SAND
SAND
SAND
SAND
SAND
SAND
Sl-68-(1-5)
Sl-68-(1-5)
Sl-68-(1-5)
Sl-68-(1-5)
S1-68-(1-5)
S1-68-(1-5)A
S1-68-(1-5)A
S1-68-(1-5)A
S1-68-(1-5)A
S1-68-(1-5)A
S37-2-(1-7)A
S37-2-(1-7)A
S37-2-(1-7)A
S37-2-(1-7)A
S37-2-(1-7)A
S37-2-(1-7)A
S37-2-(1-7)A
S32-38-(1-5)
S32-38-(1-5)
S32-38-(1-5)
Fl-HELP;
F5-Copy Above
F2-Entering Rows;
Field; F9-Save Data;
F3-Insert Record;
FlO-End Editing;
F4-Delete Record;
Esc-Abort
Figure 14.
Entering or editing soil data with the full-screen editor.
Several points should be made about the manner in which soil data are entered.
1. Soil horizons are numbered sequentially from the surface.
2. All horizons for a specific soil data site have the same soil name and
the same soil identifier. If the name and identifier are entered for
horizon 1, the key can be used to copy these values to the new
horizons.
3. The depths of the horizons must increase as the horizon index increases.
A particular soil file may contain up to 1000 horizons or approximately 150
soils. If more soils are needed they must be stored in additional files.
ENTER, MODIFY, OR PRINT CHEMICAL DATA FILE
This option is used to enter chemical data into a data file or to modify or
print those data. The file may contain the following data for each chemical:
CAS number
Common name
This is the unique identification number assigned to each
chemical. It may be used for selecting the chemical to be
used in the simulation.
This is the common name for the chemical. It may be used
for selecting the chemical to be used in the simulation.
Organic carbon-water partition coefficient
This is the linear sorption coefficient normalized with
respect to organic-carbon content (KOC). It must be
entered with units of ml/gram of organic carbon. This
value is combined in the model with the fractional
organic-carbon content (OC, gram organic carbon/gram soil)
to determine the linear sorption coefficient or partition
coefficient for the soil (KD) by means of the equation
KD KOC.OC
Octanol-water partition coefficient
The ratio of the concentration of chemical in octanol to
that in water.
Henry's constant
Molecular weight
Density
The ratio of the concentration of chemical in air to that
in water. The value stored has units of atm-m3/mole.
This is the sum of the atomic weights making up the
chemical. The units are grams/mole.
This is the mass per unit volume of the chemical in
grams/cm3.
Melting point This is the temperature in degrees Celsius at which the
chemical in solid form converts to liquid form (at
standard pressure).
Boiling point This is the temperature in degrees Celsius at which the
chemical in liquid form converts to gaseous form (at
standard pressure).
Solubility in water
The concentration (mg/1) of the chemical in water at
saturation at 25' C.
Vapor pressure
Total surface area
This is the pressure (in mm of Hg) exerted by the vapor
form of the chemical when at equilibrium with the chemical
in liquid form at standard temperature and pressure.
The surface area of one molecule of the chemical (sq.
Angstroms).
Critical concentration
The concentration (in ig/1) of chemical
that is considered hazardous to human
parameter is equivalent in value to
contaminant level goal (MCLG) as determined
in groundwater
beings. This
the maximum
by the USEPA.
Biological half-life
This is the length of time (days) required for one-half of
the present concentration to be degraded biologically.
Hydrolysis half-life
This is the length of time (days) required for one-half of
the present concentration to be hydrolyzed.
Although the file can contain all of these entries, all are not required.
Upon
used
only
entering this option the user is asked to specify the chemical file to be
(Figure 15). Since, in this example, the user wanted the default file,
the key was pressed. The user then chose the Edit option.
When option 'F' is chosen, the user is prompted for the name of the text file.
If that file does not exist, it is created. If it exists, the output is
appended to the end of the file. The user is also asked if the file should be
output with titles for each field. If titles are wanted the text file will be
similar to the screen listing. If not, only data are output with one record
per line and values for fields within a record separated by commas.
Enter Name of File to be Used [Default is CHEM.CHM]:
OPTIONS:
E. Enter or edit data in file
P. Print data in file
S. Display data on screen
F. Convert data to a text file
Desired Option: E
Selecting the chemical file and the edit option.
Figure 15.
Chemical data can be edited and entered using the full-screen editor as shown
in Figure 16. In this case each line represents a single chemical. Fields not
on the screen will be scrolled on horizontally as needed. Common names can be
up to 60 characters in length. Since this is too long for the display, those
characters which will fit are displayed on the row in the normal place. The
entire name for the chemical being entered is displayed near the bottom of the
screen. That name remains there as the screen scrolls horizontally. Each
chemical file can store data for up to 400 chemicals. If more chemicals are
needed, additional files may be used.
Record
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Common Name:
CAS Number
15972-60-8
116-06-3
107-18-6
834-12-8
120-12-7
1912-24-9
86-50-0
71-43-2
314-40-9
75-25-2
1563-66-21
56-23-5
133-90-4
108-90-7
67-66-3
76-06-2
2921-88-2
470-90-6
66-81-9
ALDICARB
Common Name
Koc
(ml/g OC)
ALACHLOR 1.900E+002
ALDICARB 1.700E+001
ALLYL ALCOHOL
AMPTRYN 3.870E+002
ANTHRACENE 2.200E+005
ATRAZINE 1.600E+002
AZINPHOS-METHYL
BENZENE 7.700E+001
BROMACIL 7.200E+001
BROMOFORM 1.160E+002
CARBOFURAN 2.550E+001
CARBON TETRACHLORIDE4.390E+002
CHLORAMBEN
CHLORDANE 3.800E+004
CHLOROBENZENE 3.300E+002
CHLOROFORM 4.400E+001
CHLOROPICRIN
CHLORPYRIFOS 6.100E+003
CLORFENVINPHOS
CYCLOHEXIMIDE
Fl-HELP; F2-Entering Rows;
F5-Copy Above Field; F9-Save Data;
F3-Insert Record; F4-Delete Record;
F10-End Editing; Esc-Abort
Entering chemical data into file.
Figure 16.
ENTER, MODIFY, AND PRINT RAINFALL DATA FILE
This option is used to enter, edit, or display daily effective rainfall
records. Effective rainfall is used here to mean the amount of water entering
the soil. The source of the water may be either irrigation or rainfall. Water
known to run off the soil surface should not be included.
Rainfall may be entered in metric units of millimeters. Figure 17 illustrates
the manner in which the user selects the file to be edited, displayed, or
converted to a text file. When option 'F' is chosen, the user is prompted for
the name of the text file. If that file does not exist, it is created. If it
exists, the output is appended to the end of the file. The file will be
similar to the screen listing.
Figure 17. Selecting rainfall file and edit option.
Figure 18 illustrates the editing screen for rainfall data. This option also
uses the full-screen editor. The editor provides the date automatically, so
the user only needs to enter the effective rainfall amounts on the proper
dates. Other days may be left containing only decimal points.
Rainfall files may contain up to 15 years of data. This software cannot be
used for simulations exceeding 15 years.
Enter Name of File to be Used : b:local83
OPTIONS:
E. Enter or edit data in file
P. Print data in file
S. Display data on screen
F. Convert data to a text file
Desired Option: e
Effective Rainfall
(mm)
8.38
17.27
Date I
1- 1-1985
1- 2-1985
1- 3-1985
1- 4-1985
1- 5-1985
1- 6-1985
1- 7-1985
1- 8-1985
1- 9-1985
1-10-1985
1-11-1985
1-12-1985
1-13-1985
1-14-1985
1-15-1985
1-16-1985
1-17-1985
1-18-1985
1-19-1985
1-20-1985
Fl-HELP;
FS-Copy Above
F2-Entering Rows; F3-Insert Record; F4-Delete Record;
Field; F9-Save Data; F10-End Editing; Esc-Abort
Entering or editing rainfall data with the full-screen editor.
7.11
Figure 18.
ENTER, MODIFY, AND PRINT EVAPOTRANSPIRATION DATA FILE
This option is used to enter daily evapotranspiration amounts for the site of
interest. Evapotranspiration is the total amount of water lost by evaporation
from the soil surface and transpiration through the plant. User interaction
with the computer for this option is identical to that for the rainfall files
illustrated previously. Evapotranspiration files are limited to 15 years of
data, as are rainfall files.
DISPLAY FILE DIRECTORY
This option is used to display the names of files and subdirectories on disk
drives. To specify the disk drive and type of directory listing desired, the
user is asked to enter the desired mask. A mask is a series of characters
which specify the disk drive, disk directory, or group of files to be listed.
Examples of common masks are illustrated below.
*.* List all the files in the default disk drive.
A:\*.* List all the files in the root directory of drive A.
*.R List all files in the default directory with an extension
of R.
CHEMRANK.* List all files in the default directory with filename
CHEMRANK.
SELECT DEFAULT FILES
This option, illustrated in Figure 19, is used to select the soil and chemical
data files-to be used in option A. It may be used if several soil or chemical
data files are used or if the files to be used are on a disk drive other than
the default disk drive.
Configuration Option
Name of Chemical Data File :CHEM.CHM
Name of Soil Data File :SOIL.S
Use cursor keys to position cursor. Then make desired changes.
Press when finished entering all information.
Press for help. Press to abort this option.
Selecting default files.
Figure 19.
IMPORT ASCII DATA FILES
Some data required in this model may already exist in computer-readable form.
In these cases, it may be advantageous to create ASCII files of the data and
to import the data into this software. This option reads selected ASCII files
and creates binary files used in this software.
The menu shown in Figure 20 is used to select the type of file to be imported.
In each case, the system asks for the name of the ASCII file and the units
used, if relevant. The system then reads the file into random access memory.
The user is then prompted for the name of the output file. At this point the
data are displayed in the full-screen editor. The user may inspect or edit the
data. The data will be written to the output file if the user presses the
or keys, as is done for normal editing.
"i N
Figure 20.
Menu for importing data files.
A description of the required form of the input data is given on the following
pages.
IMPORT ASCII DATA FILES
OPTIONS :
S. Soil Data File
C. Chemical Data File
R. Rainfall Data File
E. Evapotranspiration Data File
Q. Quit. Return to Main Menu.
Desired Option ?
Soil Data File
For each soil, the following sequence of parameters must
be stored in the ASCII file. Each parameter must be on a
separate line.
1. Soil name
2. Soil identifier
3. Number of horizons
4. For each horizon:
a. Depth of bottom of horizon, (meters)
b. Organic carbon content, (%)
c. Bulk density, (g/cm3)
d. Soil-water content at -0.01 MPa, (% by volume)
e. Soil-water content at -1.5 MPa, (% by volume)
f. Soil-water content at saturation, (% by
volume)
NOTES:
1. All the parameters for horizon 1 are given before
those for horizon 2, etc.
2. This format is not the same as that used for soil
files in CMIS (Nofziger and Hornsby, 1985).
3. The soil file used in this software is identical to
that use in the CMLS software, so the same file can
be used by both programs.
Chemical Data File
The following sequence of parameters must be stored in the
ASCII file for each chemical. Each parameter must be on a
separate line.
1. CAS number
2. Common name
3. Organic carbon-water partition coefficient, (ml/g
OC)
4. Octanol-water partition coefficient, dimensionlesss)
5. Henry's constant, (atm-m3/mole)
6. Molecular weight, (g/mole)
7. Density, (g/cm3)
8. Melting point, ('C)
9. Boiling point, (C)
10. Solubility in water, (mg/1)
11. Vapor pressure, (mm Hg)
12. Total surface area, (A2)
13. Critical concentration, (pg/l)
14. Biological half-life, (days)
15. Hydrolysis half-life, (days)
NOTE: If a parameter is unknown, a period or a decimal
point must be entered on that line of the text file.
Rainfall Data File
The following values must be stored in the ASCII file for
each rainfall event. Each parameter must be on a separate
line.
1. Month (as a number from 1 to 12)
2. Day
3. Year
4. Effective rainfall, (inches or millimeters)
NOTES:
1. This file structure is identical to that
CMIS (Nofziger and Hornsby, 1985).
used in
2. The rainfall file used in this software is identical
to that used in the CMLS software, so the same files
can be used by both programs.
Evapotranspiration Data File
The following values must be stored in the ASCII file for
each day. Each parameter must be on a separate line.
1. Month (as a number from 1 to 12)
2. Day
3. Year
4. Evapotranspiration, (inches or millimeters)
NOTES:
1. If an evapotranspiration file does not contain data
for a certain day, the value present for the
previous day is used in the model.
2. This file structure is identical to that used in
CMIS (Nofziger and Hornsby, 1985).
3. The evapotranspiration file used in this software is
identical to that used in the CMLS software, so the
same files can be used by both programs.
DESCRIPTION OF RANKING SCHEMES
Retardation Factor: Ranking by retardation factor, RF, is ranking by one
simple estimate of the time required for the chemical to move through the
soil. Chemicals with smaller values for RF move more rapidly than chemicals
with larger values. Therefore, chemicals with lower retardation factors are
likely to reach the groundwater more quickly than those with larger values.
Ranking by this scheme assumes that chemicals which move more rapidly have
greater potential for contaminating groundwater.
The retardation factor, RF, for a uniform soil is given by
RF 1 + (pKD + (f OFC)Kh)/9FC (1)
where p is the bulk density of the soil, f is the porosity of the soil, eFC is
the volumetric soil-water content at "field capacity", KD is the partition
coefficient for the chemical in the soil, and Kh is the dimensionless Henry's
constant for the chemical.
For a layered soil, the time required to move through the N layers to the
depth of interest is the sum of the times required for each layer. If di, i =
1,2,3,...,N, represents the depth of the bottom of each layer and do = 0, then
the time, ti, required to move through layer i is given by
ti (di-di-1) RFi 9FCi / qi (2)
where 9FCi is the field capacity for the layer i, qi is the recharge rate
through layer i, and RFi is the retardation factor for layer i. RFi is given
by equation 1 using soil parameters for layer i. The total travel time T is
given by
T tI + t2 + t3 + ... + tN (3)
Also
T = dN RF 9FC / q (4)
where RF, BFC, and q are average parameters for the profile. Assuming qi to be
uniform over all horizons,
RF = 2 wi RFi 8FCi / eFC (5)
and
9FC 2 wi 0FCi
where wi (dj di-1) / dN. Equation 5 is the operational equation for
determining the retardation factor for a layered soil.
Attenuation Factor: Ranking by attenuation factor, AF, is ranking the
chemicals on the basis of the relative amount of chemical passing the depth of
interest. This factor incorporates both travel time and degradation rate to
come up with a ranking among chemicals. Ranking by this scheme assumes that
the larger the mass of chemical moving past the depth of interest, the greater
is its potential for contaminating groundwater. The relative amount of
chemical passing through the soil in time tj is given by
MI / MO exp(-kl t1) (7)
where MO and MI are the mass of chemical at the top and bottom of the soil,
respectively, and kI is the degradation constant. In this simple case the
attenuation factor is given by
AF exp(-kl t1) (8)
For a soil with multiple layers having different degradation rates or travel
times, equation 7 can be applied to each layer. If MN represents the mass
moving out of the bottom of layer N, then
MN /MO exp(-k1*tl-k2*t2-...-kN*tN) (9)
and the attenuation factor is given by
AF exp(-kl*tl-k2*t2-...-kN*tN) (10)
Equation 10 forms the basis for calculating the attenuation factor for layered
soils. Equation 2 is used for calculating ti. The recharge rate is assumed
constant for all soil layers. The degradation constants are given by
ki 0.693 / half-lifei (11)
where half-lifei is the half-life of the chemical in layer i.
Travel Time from CMLS: The two ranking schemes listed above involve numerous
assumptions as discussed by Rao et al. (1985). CMLS is a model developed by
Nofziger and Hornsby(1985) for predicting the location of chemicals applied to
soils. This model requires somewhat more data about the soil as well as daily
infiltration and evapotranspiration records. If the data are available, the
chemicals can be ranked using this model. This ranking scheme for travel time
is similar to that of the retardation factor but with fewer assumptions. In
this case a water balance is calculated for each day based on known
infiltration and evapotranspiration amounts. Thus, the flux of water passing
the chemical each day is calculated, rather than assumed constant as is done
in calculating the retardation factor. This scheme ignores chemical losses by
volatilization.
Mass Emissions from CMLS: This ranking scheme is similar to that of the
attenuation factor in that it is based on estimates of the amount of chemical
passing the depth of interest. In this case the amount passing is determined
by use of the CMLS algorithm rather than the simplified equation given for AF.
Here volatilization is also ignored.
RULES FOR DETERMINATION OF CHEMICAL PARAMETERS
Several schemes are built into the model to estimate parameters needed. The
estimation process used depends upon the data available. Rules used for each
parameter are given below.
1. Partition coefficient, KD:
Rule 0: If the partition coefficient for the chemical of interest is
known for a soil horizon and is entered by the user, that value will be
used.
Rule 1: If the partition coefficient is not known but the organic
carbon-water partition coefficient is known, the partition coefficient
for the chemical will be determined using
KD KOC OC
where KOC is the organic carbon-water partition coefficient and OC is
the fractional organic-carbon content of the soil horizon. This
relationship has been found valid for many soils and chemicals by
Hamaker and Thompson (1972) and by Karickhoff (1981, 1984).
Rule 2: If the KOC is not known, it will be estimated using the relation
loglo(Koc) -0.92 loglo(X) 0.01*(T-25) 1.404
where
X = (solubility in water/molecular wt./55556)
T maximum of the melting point or 25* C
Rule 3: If the KOC is still unknown due to missing information, it will
be estimated using
loglo(Koc) = 0.18 + 1.03 log10(KOW)
where KOW is the octanol-water partition coefficient.
Rule 4: If KOC is still unknown, insufficient data exist to rank the
chemical.
2. Dimensionless Henry's Constant, Kh: The dimensionless Henry's constant
is determined using
Kh KH / 0.024
where KH is Henry's constant in atm-m3/mole.
Rule 1: If KH is not known it is estimated using
KH (vapor pressure molecular wt.) / (760 solubility).
Rule 2: If KH is still unknown, assume KH 0.
3. Half-life: The half-life for each chemical is stored in the chemical
data file.
Rule 1: If the user does not enter values, the biological half-life
stored in the chemical file will be used.
Rule 2: If no half-life data are available, ranking by attenuation
factor and mass emissions cannot be done.
REFERENCES
1. Aller, Linda, T. Bennett, J. Lehr, and Rebecca Petty. 1985. DRASTIC: A
standardized system for evaluating groundwater pollution potential using
hydrogeologic settings. USEPA Office of Research and Development,
Washington, DC. 384p.
2. Hamaker, J.W., and J.M. Thompson. 1972. Adsorption. In Goring, C.A.I.,
and J.W. Hamaker. (ed.) Organic Chemicals in the Environment. Marcel
Dekker inc., NY. pp. 49-143.
3. Jury, W.A., W.F. Spencer, and W.J. Farmer. 1983. Behavior assessment
model for trace organic in soil: I. Description of model. J. Environ.
Qual. 12:558-564.
4. Jury, W.A., W.F. Spencer, and W.J. Farmer. 1984a. Behavior assessment
model for trace organic in soil: II. Chemical classification and
parameter sensitivity. J. Environmental Qual. 13:567-572.
5. Jury, W.A., W.F. Spencer, and W.J. Farmer. 1984b. Behavior assessment
model for trace organic in soil: III. Application of the screening
model. J. Environmental Qual. 13:573-579.
6. Karickhoff, S.W. 1981. Semi-empirical estimation of sorption of
hydrophobic pollutants on natural sediments and soils. Chemosphere
10:833-846.
7. Karickhoff, S.W. 1984. Organic pollutant sorption in aquatic systems. J.
Hydr. Eng. 110:707-735.
8. Nofziger, D.L., and A.G. Hornsby. 1985. Chemical movement in soil: IBM
PC user's guide. IFAS, University of Florida. Circular 654.
9. Nofziger, D.L., and A.G. Hornsby. 1986. A microcomputer-based management
tool for chemical movement in soil. Applied Agricultural Research
1:50-56.
10. Nofziger, D.L. and A.G. Hornsby. 1987. Chemical movement in layered
soils: User's manual. University of Florida. IFAS. Cir. 780, 44 pp.
11. Rao, P.S.C, A.G. Hornsby, and R.E. Jessup. 1985. Indices for ranking the
potential for pesticide contamination of groundwater. Soil and Crop
Science Soc. of Florida 44:1-8.
APPENDIX
USE OF THE FULL-SCREEN EDITOR
Full-Screen Data Editor: Data may be entered and edited using a full-screen
editor as illustrated in Figures 14, 16, and 18. It is convenient to think of
each file as a two-dimensional table. The rows in the file are called
"records" and the columns are called "fields". The editor is designed to
permit the user to enter or edit data for any record or field. The user simply
moves the cursor to the record and field of interest and makes the desired
entry. Values entered are compared with the range of values permitted in that
field. If the value is out-of-range, a message is displayed and the user must
change the value before moving on. The software uses the cursor-control keys
and the function keys to carry out the many diverse functions of the editor.
The following pages list various keys and their functions.
This key is used to move the cursor to the right within
the present field. If the cursor is located at the end of
a field, this key will move the cursor to the beginning of
the next field. If the cursor is at the end of the last
field of the record, the cursor moves to the first field
of the following record.
This key is used to move the cursor to the left within the
present field. If the cursor is located at the beginning
of a field, this key will move the cursor to the beginning
of the preceding field. If the cursor is at the beginning
of the first field of the record, the cursor moves to the
last field of the preceding record.
This key is used to move the cursor up one record.
This key is used to move the cursor down one record.
This key is used to move the cursor left one field. If the
cursor is in the first field of the record, the cursor
moves to the last field of the preceding record.
This key is used to move the cursor right one field. If
the cursor is in the last field of the record, the cursor
moves to the first field of the following record.
This key moves the cursor to the first record in the file.
The field is unchanged.
This key moves the cursor to the last record in the file.
The field is unchanged.
This key is used to move the cursor up 20 records (one
screen). The field is unchanged.
This key is used to move the cursor down 20 records-(one
screen). The field is unchanged.
This key displays help information for the field being
entered. The help information remains displayed until the
user moves the cursor out of the current field or record.
At that time the function-key descriptions are again
displayed.
Data may be entered by rows or by columns. This key is
used to select the preferred method of entry. The choice
determines the field to which the cursor moves after the
key is pressed.
This key is used to insert a new record into the file. The
new record is inserted just above the record containing
the cursor at the time the key is pressed. Data in all
records below this one are moved down to make room for the
new record. The new record is filled with decimal points
to indicate that no data have been entered into this
record. Data present in the last record of the file will
be lost.
This key is used to delete the record in which the cursor
is located. The user is asked to confirm that the record
should be deleted. After deleting a record data in records
below the one deleted are moved up. The fields in the last
record in the file are filled with decimal points to
indicate that no data have been entered.
Depressing this key causes the value in the field above
the cursor (i.e. the previous record) to be copied to the
field containing the cursor. This is useful when several
consecutive records in a file contain the same information
(e.g. soil name and identifier for all horizons of one
soil).
This key is used to write data stored in random access
memory in a disk file. After saving these data, the user
may continue using the editor. Users should get in the
habit of saving data to disk regularly (approximately
every ten minutes) as a precaution against power failures
and other system problems.
This key saves the data on disk just as does key F9.
However, after saving the data, control returns to the
main menu.
This key is used to sort a file so that entries in
selected fields are arranged alphabetically. If this key
is pressed when the cursor is located in the common-name
or CAS-number fields of the chemical file or it is located
in the soil name or soil-identifier field of the soil
file, that file will be sorted alphabetically on that
field and the restructured data will be displayed on the
screen in the new order. The user may save the sorted data
on disk (writing over the original file) by pressing the
or key as explained above. If the user presses
the key after the file has been sorted, the old file
on the disk will not be replaced by the sorted file.
This key is used to end data entry or editing of a
particular field. Characters to the right of the cursor
are dropped. If there are no characters to the left of the
cursor, the key does nothing. If the system is set
for entering by row (see above), the cursor is moved
right one field. If the system is entering by columns, the
cursor moves down one record.
This key is used to delete the character to the immediate
left of the cursor.
This key is used to delete the character at the cursor
location.
Pressing the key aborts the present option. Nothing
is written to disk, so the disk file remains as it was the
last time data were saved.
Decimal point If a user enters only a decimal point in a field, the
system considers this as 'no data'.
IMPORTANT: The user must exit from the editor using if the data entered
into random access memory are to be written on a disk file. Aborting by means
of the key does not save any of the contents of memory in a disk file.
Index
A
abort 10
alphabetizing files 54
application depth 17
attenuation factor 12,
21, 46
C
chemical parameters 8, 32
chemical selection 18
control depth 17
cursor keys 10, 52, 53,
54
D
data files
importing 40
default files 39
E
Esc 54
escape key 10, 54
evapotranspiration 8, 15,
17, 37
F
file
chemical 39
soil 39
file names 10
file size
chemical 34
evapotranspiration 37
rainfall 35
soil 31
files
ASCII 20
importing 40
full-screen editor 52
special keys 52, 53,
54
function keys 10, 52, 53,
54
6
graphics printer 7, 8
H
half-life 33, 49
hardware 7
help messages 10, 53
Henry's constant 45, 48
I
infiltration 17, 35
L
linear sorption
coefficient 32, 45
mass emissions 13, 21, 47
missing data 54
0
operating system 7
output device 20
output options 20
P
partition coefficient 32,
45, 48
R
rainfall 8, 17, 35
ranking schemes 16
recharge rate 17
retardation factor 12,
20, 45
rooting depth 17
rules
half-life 49
Henry's constant 48
partition coefficient
48
S
screen attributes 8
software execution 9
soil identifier 17
soil parameters 8, 29
sorting files 54
special keys 52, 53, 54
T
travel time 13, 21, 46
This publication was produced at a cost of $214.11, or $1.29 per copy, to provide guidance in using the software
to extension specialists, agents, farmers, state regulatory and action agencies. 10-166-88
COOPERAIVE EXTENSION SERVICE. UNIVERSITY OF FLORIDA. INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES. K.R. Telertiller.H
director, in coopwa"n with fe United StaeM Department of Agriculture publiehes titl Intoralon to further the purpome of the 8 and
June 30 1914 AMi d Congress; and is authond to provide reeMrch educational Inlnon an md o ner services only to individual n tu-
M # that funon without reM d to rmce, coloM. s. a -e. handloep or national ongin. Single copes of Extanmon puAcalcons (amcluding "H
and south pubilcaton are valuable free to Florida reidene oimn County Extenaon O1-ces. Inlormatan on bulk rataar copie lor outlc-sata
punrch ae is available from CM. Hilnon. PubHicatons Diribution CnK IFAS Building 664, Uniety Florid Ginvil Floda 3611. r pu
pthe ublicatIon edior should contact this address to detonmin avalablllty.
