&EPA
United States
Environmental Protection
Agency
Environmental Research
Laboratory
Athens GA 30613
EPA/600/3-85/038
May 1985
Research and Development
Exposure Analysis
Modeling System:
Reference Manual for
EXAMS II
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EPA/600/3-85/038
May 1985
EXPOSURE ANALYSIS MODELING SYSTEM
Reference Manual for EXAMS II
by
Lawrence A. Burns
Environmental Research Laboratory
U.S. Environmental Protection Agency
Athens, Georgia 30613
and
David M. Cline
Office of Information and Resource Management
U.S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U. S. ENVIRONMENTAL PROTECTION AGENCY
ATHENS, GEORGIA 30613
U.S. Environmental Protection Agency
Region V, Library
230 South Dearborn Street
Chicago, Illinois 60604
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DISCLAIMER
The information in this document has been funded wholly or in part by the
United States Environmental Protection Agency. It has been subject to the
Agency's peer and adminstrative review, and it has been approved for publica-
tion as an EPA document. Mention of trade names or commercial products does
not constitute endorsement or recommendation for use.
U;S. Environmental Protection Agency
ii
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FOREWORD
Environmental protection efforts are increasingly directed toward preventing
adverse health and ecological effects associated with specific compounds of
natural or human origin. As part of this Laboratory's research on the occur-
rence, movement, transformation, impact, and control of environmental contam-
inants, the Environmental Systems Branch studies complexes of environmental
processes that control the transport, transformation, degradation, fate, and
impact of pollutants or other materials in soil and water and develops models
for assessing exposures to chemical contaminants.
Concern about environmental exposure to synthetic organic chemicals has
increased the need for techniques to predict the behavior of chemicals enter-
ing the environment as a result of the manufacture, use, and disposal of
commercial products. The Exposure Analysis Modeling System (EXAMS), which has
been undergoing development, test, and revision at this Laboratory since 1978,
provides a convenient tool to aid in judging the environmental consequences
should a specific chemical contaminant enter a natural aquatic system. Because
EXAMS requires no chemical monitoring data, it can be used for new chemicals
not yet introduced into commerce as well as for those whose pattern and volume
of use are known. EXAMS and other exposure assessment models should contribute
significantly to efforts to anticipate potential problems associated with
environmental pollutants.
Rosemarie C. Russo
Director
Environmental Research Laboratory
Athens, Georgia
111
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PREFACE
The first version of the EXAMS computer code concentrated on the long-term
results of continual, steady discharges of single chemicals into typical
aquatic systems. Comments and requests from users (notably EPA's Office of
Pesticide Programs and Office of Toxic Substances) have led to expansions of
EXAMS' capabilities to:
1. include seasonal differences in the environmental driving
forces that govern transport and transformation kinetics,
2. compute the fate and transport of products that result
from transformation reactions in the environment, and to
3. provide greater flexibility in specifying the timing and
duration of chemical loadings entering the ecosystem.
These objectives were implemented as follows.
1 . Seasonal effects were added to EXAMS by expanding the environmental
data to allow for 12 (monthly) entries, plus an average value at sector
1 3 of the database. The average values can be specified directly, or
computed from the monthly data, as a user option. To simplify data aqui-
sition, EXAMS II estimates some quantities that EXAMS I requires as input
data. Most importantly, EXAMS II generates the solar light field from
meteorological data. This algorithm is based on results from the research
group led by A.E.S. Green at the University of Florida. From the lati-
tude and elevation of the location, plus (monthly) data on atmospheric
ozone, air mass types, atmospheric turbidity, and relative humidity,
EXAMS computes 46 values of (clear-sky, 24-h average) photon flux density
(photons/s/cm2/N nm where N is the bandwidth) covering the solar spectrum
from 280 to 800 nm.
2. Transformation products are computed for each spatial and temporal
(monthly) segment defined by the analyst. The program uses information
describing the (temperature-dependent) mole/mole yield of product(s) from
each of nine reaction processes (direct photolysis, etc.). The yields are
further separated according to ionic speciation (up to seven species) and
according to physical separation into dissolved, complexed (with "dis-
solved" organic matter), sediment-sorbed, and biosorbed forms (the latter
for metabolic transformation processes only). The code checks for mass
balance closure (i.e., it detects attempted transformations in excess of
the available parent materials), and generates autochthonous chemical
IV
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loadings of the product chemicals. The fate and transport of the pro-
ducts are computed from process data held in the chemical database, that
is, the behavior of daughter compounds is simulated in the same way as
are the parent chemical(s).
3. EXAMS II includes two time-varying operational modes, in addition to
the (Mode 1) steady-state capabilities implemented in EXAMS I. In Mode 2
operations, the user is ceded command of the integrator timer controls,
and thus can evaluate the transport and fate of chemicals via initial-
value problem approaches. Both steady chemical loadings and/or pulse
loads (i.e., initial conditions) can be imposed on each spatial segment.
A RUN command then invokes an integration package to simulate chemical
behavior over the user-chosen interval. A "CONTINUE" command lets the
user evaluate intermediate results, modify chemical loadings or environ-
mental conditions, and re-invoke the integrator for additional sequenced
simulations. Mode 3 simulations return control of the integrator to
EXAMS, but give the user automated access to the entire suite of time-
varying (monthly) environmental parameters. In Mode 3 operations, a
suite of steady loadings can be set to vary on a monthly basis and, in
addition, a chemical pulse can be loaded into any segment on any day (or
series of days) of the year. In this way, complex load patterns due to
the vagaries of manufacturing schedules and weather conditions can be
accommodated. A Mode 3 "RUN" encompasses a minimum of one year, with no
explicit maximum. During Mode 3 operations, EXAMS reports the 24-h, 96-
h, and chronic exposure concentrations experienced in the system, as well
as a sensitivity analysis reflecting the non-linear (i.e., second-order)
nature of the governing equations. The integrators used in EXAMS II are
double precision, variable-order variable-stepsize codes employing Adams
methods upon initial invocation, followed (when necessary) by invocation
of a "Gear's method" backward differentiation code for problems diagnosed
as stiff.
There are additional differences between the EXAMS I and EXAMS II codes: The
treatment of ionic speciation and sorption has been expanded to include tri-
valent ions and complexation with "dissolved" organic matter. EXAMS now
computes the concentration of singlet oxygen in the water column, and the
chemical database accepts rate constants for this transformation process.
Reductive transformations have been included as a (provisional) second-order
empirical equation. Oxidizing radicals are now entered as single near-surface
values, and the code computes segment concentrations from light extinction in
the ulra-violet. The suite of output tables has been expanded to include a
description of ionic speciation, to accomodate the new input data (product
chemistry, pulse loadings), and to provide analogous outputs for all opera-
tional modes. The physical geometry of the system can now be specified in
several alternative ways — for example, EXAMS II can accept the length,
width, and mean depth of a reach, and itself compute segment volumes, etc.
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ABSTRACT
The Exposure Analysis Modeling System (EXAMS), published in 1982 (EPA-600/3-82-
023) provides rapid evaluations of the behavior of synthetic organic chemicals
in aquatic ecosystems. EXAMS combines laboratory data describing reactivity
and thermodynamic properties of chemicals with independent data describing the
transport and physical/chemical properties of aquatic ecosystems. From these
data, EXAMS computes:
1) Exposure: the expected (long-term chronic, 24-hour and 96-
hour acute) environmental concentrations due to a user-
specified pattern of chemical loadings,
2) Fate: the distribution of the chemical in the system and
the relative dominance of each transport and transfor-
mation process, and
3) Persistence: the time required for effective purification
of the system (via export/transformation processes) once
the chemical loadings terminate -(in evaluative Mode 1
analyses).
EXAMS is an interactive program; it allows a user to specify and store the
properties of chemicals and ecosystems, modify the characteristics of either
via simple English-like commands, and conduct an efficient, rapid series of
evaluations and sensitivity analyses that help the analyst discern the prob-
able aquatic fate and effects of synthetic organic chemicals.
This manual describes the expansion of the EXAMS code to extend its capabilities
to include seasonal differences in the environmental driving forces that govern
transport and transformation kinetics, to compute the fate and transport of
products that result from transformation reactions in the environment, and to
provide greater flexibility in specifying the timing and duration of chemical
loadings entering the ecosystem. Among other improvements, EXAMS II expands
the treatment of ionic speciation and sorption to include trivalent ions, and
complexation with "dissolved" organic matter. The suite of output tables has
been expanded to accommodate product chemistry, pulse loadings, and other new
input data and to provide analogous outputs for all operational modes.
This report covers a period from January 30, 1981 to April 15, 1985, and work
was completed as of April 15, 1985.
was completed as of April 15, 1985.
VI
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TABLE OF CONTENTS
Disclaimer -11
Foreword 11:L
Preface i-v
Abstract vi
EXAMS Command Language User's Guide 1
System Command Descriptions
AUDIT 8
CATALOG 10
CHANGE 13
CONTINUE 15
DESCRIBE 19
DO 21
ERASE 24
EXIT 26
HELP 27
LIST 30
NAME 33
PLOT 35
PRINT 41
QUIT 42
RECALL 43
RUN 45
SET 46
SHOW 48
STOPE 52
ZERO 54
Glossary of EXAMS System Parameters 56
Vll
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EXAMS Command Language User's Guide
This section describes the EXAMS command language, including usage and
reference information. The first part of the Section provides an overview of
the command language and its grammar. The second part contains detailed
descriptions of each command. The commands are listed in alphabetical order.
Conventions used in this Section:
Convention Meaning
CTRL/x The phrase CTRL/x indicates that you must press the
key labeled CTRL while you simultaneously press an-
other key, for example, CTRL/O.
EXAMS > LIST 7 Vertical series of periods, or ellipsis, mean that
not all the data EXAMS would display in response to
the particular command is shown, or that not all
the data a user would enter is shown.
keyword,... Horizontal ellipsis indicates that additional key-
words, command parameters, or data can be entered in
a command sequence, or that EXAMS displays additional
data as part of the sample output line.
[keyword] Sguare brackets indicate that the item enclosed is
optional, that is, the entity can be omitted from the
command line altogether.
Overview:
The EXAMS command language provides users with a set of commands for:
o Entering, storing, and manipulating data describing the reaction
chemistry of synthetic compounds, the environmental parameters
governing their transport and fate in aquatic systems, patterns of
allochthonous loadings, and product chemistry.
o Studying the results of an analysis by listing tabular output on
your terminal, plotting the concentration data ("Expected Environ-
mental Concentrations" or EECs) computed durinq simulations, and
printing paper copy for later reference.
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Choosing an analytical framework for investigating exposure to
chemicals in a particular case study: EXAMS includes three
operational modalities or "MODEs":
MODE Analytical Methodology
1 Long-term consequences of continued releases of
chemicals; steady-state analysis.
2 Detailed examination of immediate consequences of
chemical releases; initial-value problems.
3 Intermediate-scale resolution of events over several
years, including effects of seasonal environmental
variability; analysis of time-series data.
Entering Commands
EXAMS commands consist of English-language words (usually verbs) that describe
what you want EXAMS to do. Some commands include options that modify their
operation. They provide EXAMS with more information on how you want the
command to be executed. Some commands require a description of the object to
be acted on by the command. In some cases, the object is a keyword (as in the
HELP command); sometimes it is an EXAMS data element (SET command), or a
section of a file of input data or analysis results (STORE and LIST commands).
Throughout this section, EXAMS commands are printed in uppercase letters. You
can, however, enter these commands in uppercase, lowercase, or a mixture of
uppercase and lowercase letters.
The following example shows an AUDIT command and EXAMS' response, as they
would appear on your terminal:
EXAMS > AUDIT ON
All input will now be copied into the file
named AUDOUT.DAT on Fortran unit number 4
EXAMS > ! This Command File should be renamed file.EXA
FXAMS >
EXAMS analyzes the parts of the above example as follows.
EXAMS > The EXAMS system prompt for command input; a greater-than (>)
means that EXAMS' command interpreter is ready for you to enter
a command.
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AUDIT The command name, requesting that EXAMS enable/disable the User
Notepad/Command File Creation facility.
ON An option of the AUDIT command, requesting that the Notepad/
Create facility be enabled.
All input will now be copied into the file
named AUDOUT.DAT on Fortran unit number 4
A message from the AUDIT command, indicating that the command
completed sucessfully. The command interpreter used the value
of AUDOUT (4) to establish communication with an external file.
EXAMS > The next system command prompt, confirming that the command has
completed its operations (AUDIT has opened communications with
an external file and started recording terminal inputs), and
EXAMS is ready for additional input.
! This Command File should be renamed file.EXA
A comment. A comment line always begins with an exclamation
point (!) or an asterisk (*). You can use comments, as needed,
to document EXAMS analysis sessions or command procedures.
EXAMS > The next EXAMS system command prompt, confirming that the
comment has been recorded in the Notepad/Command file and EXAMS
is ready to accept another command.
Command Prompting
When you enter a command at the terminal, you need not enter the entire
command on a single line. If you enter a command that requires that you
specify its range or the object of the requested action, and you do not
include the needed information, EXAMS' command interpreter prompts you for all
missing information. For example:
EXAMS > AUDIT
The following AUDIT options are available:
ON - invokes the AUDIT option
OFF - terminates the AUDIT option
HELP - this message
EXIT - return to the EXAMS prompt.
AUDIT > ON
All input will now be copied into the file
named AUDOUT.DAT on Fortran unit number 4
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In this example, no AUDIT option was entered, so EXAMS prompts for a more com-
plete specification of the intended action. The line ending with a >
indicates that EXAMS is waiting for the additional input.
In many cases, EXAMS' prompts do not include an automatic description of
the full range of possible response options. Often, however, entering HELP in
response to the prompt will display a list of available choices, as the
following example indicates:
KXAMS > LIST
Table > HELP
1 Chemical inputs: FATE Data
2 Chemical inputs: PRODUCT Chemistry
3 PULSE Chemical Loadings
20 Exposure Analysis SUMMARY
ALL Entire Report
Table > 18
Ecosystem: Name of Waterbody
Chemical: Name of chemical
TABLE 18.01. Analysis of steady-state fate
•
(body of table)
In the example above, LIST is entered without the number of the output table
to be displayed. EXAMS prompts for the missing information; typing HELP in
response to the LIST prompt displays a catalog of the available result tables.
EXAMS Messages
When you enter a command incorrectly, EXAMS' command interpreter will display
a descriptive error messaae telling you what was wrong. For example, if you
specify a data subscript larger that the maximum currently available on your
machine, EXAMS will respond:
Subscript out-of-range.
You must then retype the command correctly.
Other error messages may be produced during the execution of a command, or
during a simulation or data display sequence. These messages can indicate
such things as incomplete environmental data, character data entered where
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numeric data is required, or typographic errors during entry of commands.
EXAMS will respond to typographic errors in command entries by displaying:
Command not recognized. Type HELP for command information.
Because the messages are descriptive, you can usually determine what correc-
tive action is required in order to proceed. When this is not the case,
EXAMS' HELP facility contains a large body of additional and supplementary
information available through the HELP, DESCRIBE, and SHOW commands.
The HELP Command
You may not always have this guide available at your terminal when you need a
summary of the syntax of a command or a definition of an input datum. The HELP
command provides this information in EXAMS' interactive environment. For
example, you can type the command:
EXAMS > HELP LIST
EXAMS responds by displaying a description of the LIST command, its syntax,
and the options you enter to specify the range of the command.
The HELP facility also provides on-line assistance for EXAMS' input data:
EXAMS > HELP QUANT
will display the subscript ranges, their meanings, the physical dimensions,
and the English definition of EXAMS chemical input datum "QUANT". This infor-
mation is available online for all EXAMS' input data and control parameters.
The names of all of EXAMS' input variables have been selected as mnemonics for
their English-language names. (For example, QUANT is the photochemical quantum
yield.) These mnemonics are used in EXAMS' output tables; definitions are
given in the Glossary of this User Manual.
EXAMS' Help facility supplies lists of individual topics and subtopics. The
HELP command is described in more detail later in this Section, and a tutorial
explanation of the command is available online by entering:
EXAMS > HELP TUTOR
Command Procedures
A command procedure is a file that contains a sequence of EXAMS commands,
optionally interspersed with descriptive comments (lines with "!" or "*" in
column one). By placing sets of frequently-used commands and/or response
options in a command procedure, you can execute all the commands in it
with a single command. For example, suppose a file called START.EXA contains
these command lines and comments:
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SET MODE TO 3
SET KCHEM TO 4
SET NYEAR TO 5
RECALL LOAD 7
! Load UDB Sector 7 is the spray vector study
You can execute the four commands in this file by entering the command:
EXAMS > DO START
or EXAMS > ©START
You do not have to specify the file type of a command procedure when you use
the @ command, so long as the file type is EXA. This is the default file type
for EXAMS' @ command. You can use another file suffix, if you so inform EXAMS
when you enter the command request. For example, to execute commands in a file
named START.UP:
EXAMS > @START.UP
Wild Card Characters
Some EXAMS commands accept a "wild card" character in their input command
specifications. The asterisk (*) is the only symbol having this function in
EXAMS. Wild card characters are used to refer to a range of data subscripts,
or other entities, by a general name, rather than having to enter a specific
name for each member of the group. Particular uses of wild cards in EXAMS
vary with the individual commands. The command descriptions later in this
Section indicate where wild cards are allowed and their effects.
Truncating Command Names and Keywords
All keywords and names of input data that you enter as command input can be
abbreviated. You need enter only enough characters to distinguish a keyword or
datum from others with similar names.
Summary Description of EXAMS' System Commands
EXAMS Command Summary Description
AUDIT Start/Stop user notepad for recording procedures
CATALOG List the contents of User Databases (UDBs)
CHANGE/SET Enter/reset input data and program controls
CONTINUE Resume integration (Modes 2 and 3 only)
DESCRIBE Report dimensions and data type of parameter
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DO or 0 Execute file of EXAMS commands (file.EXA)
ERASE Clear section of stored database (UDB)
EXIT/QUIT Abort command, or End interactive session
HELP Describes access to EXAMS on-line HELP facility
LIST Show tabular results on the screen
NAME Specify the name of a UDB, e.g., CHEM NAME IS ..
PLOT Plot results on the screen
PRINT Queue tabular results for hardcopy printing
RECALL Activate data from stored database (UDB)
RUN Begin simulation run
SHOW Display current data values or control settings
STORE Download current data into stored database (UDB)
ZERO Clear chemical loadings, pulses, or residuals
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AUDIT
Creates a copy of user input commands and responses in an external file
Related:
Control variables: AUDOUT
Commands: DO
Syntax:
Prompt:
AUDIT option
Options
ON
OFF
The following AUDIT options are available:
ON - invokes the AUDIT option
OFF - terminates the AUDIT option
HELP - this message.
EXIT - return to the EXAMS prompt.
AUDIT >
Options:
OFF
ON
Ends copying of EXAMS commands to the external file.
Begins copying of EXAMS commands to an external file.
Description:
The AUDIT command initiates copying of inputs typed at the
terminal, into an external file. These inputs include EXAMS
commands, and user responses to EXAMS prompts and option selec-
tions. The output terminus for the copy is a file named
"AUDOUT.DAT," connected to Fortran logical unit number AUDOUT.
AUDOUT can be modified (using the SET command) to any appropriate
integer. The resulting output file can be used to record an
analysis procedure, or as a general notepad. The output file can
be renamed "file.EXA" and used as an EXAMS command (DO) file.
Examples:
1. EXAMS > AUDIT
The following AUDIT options are available:
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ON - invokes the AUDIT option
OFF - terminates the AUDIT option
HELP - this message.
EXIT - return to the EXAMS prompt.
AUDIT > ON
All input will now be copied into the file
named AUDOUT.DAT on Fortran unit number 4
This command begins recording of terminal input in an external
file. The output will go to a disk file named "AUDOUT.DAT."
After leaving EXAMS, this file can be printed to give a permanent
record of the analysis.
2. EXAMS > AUDIT OFF
The AUDIT option has been terminated.
This command ends copying of EXAMS commands and responses to
the external medium (usually a disk file).
3. EXAMS > AUDIT ON
All input will now be copied into the file
named AUDOUT.DAT on Fortran unit number 4
EXAMS > RECALL ENV 2
Selected environment is: Phantom Inlet
EXAMS > RECALL CHEM 2
Selected compound is: Dichloromucktane
EXAMS > RECALL CHEM 4 AS 2
Selected compound is: Tetrabromochickenwire
EXAMS > AUDIT OFF
These commands build a file (AUDOUT.DAT) that can later be used
as a command file upon entering the EXAMS system. In this
instance, the file would be renamed (e.g., COMND.EXA) and used
to execute the above series of commands as a unit:
EXAMS > DO COMND
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CATALOG
Lists, by access number, the title of all currently active entries in the
specified User Database (UDB).
Related: Control variables: none
Commands: ERASE, NAME, RECALL, STORE
Syntax: CATALOG option
Options
CHEMICAL
ENVIRONMENT
LOAD
PRODUCT
Prompt: Enter ENVIRONMENT, CHEMICAL, LOAD, PRODUCT, HELP or EXIT >
Options: CHEMICAL
Lists the titles, by access number, of chemical databases
currently in the User Database. Each entry corresponds to
a single chemical, and contains the laboratory data des-
cribing ionization and (species-specific) partitioning and
reaction kinetics.
ENVIRONMENT
List the titles, by access number, of environmental data-
bases currently in the User Database. Each entry contains
a canonical physical and chemical model of an aquatic
system, including the environmental data needed to compute
reactivity and transport of synthetic chemicals in the
system.
LOAD
Lists the titles, by access number, of allochthonous
chemical loading patterns stored in the User Database.
These data include monthly values (kg/hour) for stream-
loads, non-point-source loads, groundwater seepage loads,
precipitation loads, and drift loads of chemicals entering
the aquatic environment, plus specification of pulse
loadings. The pulse load data include the magnitude (kg),
target environmental segment, and scheduling (month and
day) of pulses of synthetic chemicals entering the system.
PRODUCT
Lists the titles, by access number, of reaction or
transformation product chemistries stored in the User
10
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Database. These data include the Activity Database num-
bers of chemical parent and product compounds, the number
of the process responsible for the transformation, and the
yield efficiency (mole/mole) as an (optional) function of
temperature.
Description: The CATALOG command inventories the contents of the specified
User Database (UDB) and lists the titles of active entries on
the terminal screen. Four types of UDBs are available, corres-
ponding to the four options available to the CATALOG command.
The titles are listed by access number. This number is used to
STORE, RECALL, or ERASE database entries.
Examples:
1. EXAMS > CATALOG HELP
The CATALOG command supports the following options
1. ENVIRONMENT,
2. CHEMICAL,
3. LOAD,
4. PRODUCT,
5. HELP (this option), or
6. EXIT.
Enter ENVIRONMENT, CHEMICAL, LOAD, PRODUCT, HELP or EXIT >
CHEMICAL
Catalog of chemicals
No. CHEMICAL NAME
1 Unspecified Chemical
2 p-Cresol
3 Benz[a]anthracene
EXAMS >
This command lists the contents of the current User Database
for chemical data. Any of these datasets can be loaded into
the Activity Database (ADB) for study, using the RECALL command
and the appropriate access number. The first entry ("Unspeci-
fied Chemical") is a template for entering new chemical data.
11
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2. EXAMS > CATALOG ENVIRON
Catalog of environments
No. ENVIRONMENT NAME
1 Unspecified Environment
2 Pond — AERL code test data
3 Oligotrophic lake — AERL code test data
4 Eutrophic lake — AERL code test data
5 River — AERL code test data
EXAMS >
This command generates a listing of the environmental datasets
present in the User Database. Any of these can be recalled for
study using a RECALL command and the access number. The first
entry ("Unspecified Environment") is a template for entering a
new environmental model.
12
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CHANGE
Used to specify the values of data in the activity database,
Related: Commands: DESCRIBE, HELP
Syntax: CHANGE variable TO value
Prompt: CHANGE (VARIABLE TO VALUE) >
Variable: The data entry or variable to be CHANGEd can be specified
either as a single datum or, using wild cards (*), as an entire
vector, row/column of a matrix, etc.
Description: Use the CHANGE command to specify the values of data in the
activity database. "Value" can be any numerical quantity or
literal, as appropriate. "Variable" specifies an individual
element of input data or a program control parameter. Entire
vectors, rows/columns of matrices, etc. can be set to single
values using wild cards {*).
Example s:
1. EXAMS > CHANGE VOL(27) TO 7E5
Subscript out-of-range.
EXAMS > DESCRIBE VOL
VOL is a Real Vector with 25 elements.
EXAMS> CHANGE VOL(2) TO E
Invalid numeric guantity after TO.
EXAMS > CHANGE VOL(2) TO 7E5
This command sets the environmental volume of segment 2 to
7.0E+05 cubic meters. The initial attempt to set the volume of
segment 27 was rejected by EXAMS because the version in use was
set up for environmental models of 25 segments at most. The
DESCRIBE command was used to check the number of subscripts and
the dimensional size of the variable "VOL". The erroneous
13
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entry of an alphabetic for the volume was trapped by the CHANGE
command; the initial value of VOL(2) was not altered.
2. EXAMS > HELP TCEL
TCEL is a Real Matrix with 25 rows and 13 columns.
Temperature-CELsius (segment,month) Units: degrees C.
Average temperature of ecosystem segments.
Used (as enabled by input data) to compute effects of
temperature on transformation rates and other properties
of chemicals.
EXAMS > CHANGE TCEL(2,7) TO 24
This command changes the July temperature in segment 2 to 24
degrees C. The HELP command was used to check subscript dimen-
sions, maximum values, the meaning of the subscripts (subscript
#1 denotes the segment, subscript #2, the month), and the
proper units for the input datum (Celsius degrees).
3. EXAMS > HELP POH
POH is a Real Matrix with 25 rows and 13 columns.
pOH (segment,month) Units: pOH units
The negative value of the power to which 10 is raised in
order to obtain the temporally averaged concentration of
hydroxide [OH-] ions in gram-equivalents per liter.
EXAMS > CHANGE POH(*,13) TO 6.2
This command sets the average pOH (sector 13) of every segment
to 6.2. Note use of wild card "*" to specify that all segments
are to be changed. As in the previous example, HELP was used
to check subscript dimensions, units, etc. This step, of
course, is optional.
14
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CONTINUE
The CONTINUE command resumes EXAMS' simulation analysis of chemical dynamics
beginning from the current state of the system.
Related:
Syntax:
Prompt:
Options:
Description:
Examples:
Control variables: CINT, NYEAR
Commands: RUN, SHOW TIME FRAME
CONTINUE
(In Mode 2 only:)
Initial time for integration will be (nn.n) units
Enter ending time of integration, HELP, or EXIT >
None. Reply to prompt with a value greater than (nn.n).
The CONTINUE command resumes EXAMS' simulation analysis of
chemical dynamics, beginning from the current state of the
system. Chemical loadings and other input data can be altered
(CHANGEd or SET) between simulation segments; EXAMS will
re-e'valuate equation parameters as needed to incorporate the
changed conditions into the analysis.
CONTINUE cannot be invoked from Mode 1, where it is not approp-
riate. The SHOW TIME FRAME (abbreviate to SH TI F) command can
be used to assess the current state of the integrator timer
controls. In Mode 2, the Communications INTerval CINT can be
used to vary the temporal resolution in different segments of
the analysis (see Example 1). In Mode 3, NYEAR, the number of
years in a simulation time segment, can be similarly varied.
1. EXAMS > SET MODE=2
EXAMS > SHOW TIME FRAME
A RUN will integrate from
with output at intervals of
EXAMS > SET TCODE=2
EXAMS > SET TEND=10
EXAMS > SET CINT=0.25
EXAMS > ST TI F
A RUN will integrate from
with output at intervals of
0. to 24. Hours
2.00 Hours
0. to 10. Days
0.25 Days
15
-------
EXAMS > RUN
Simulation beginning for:
Environment: Pond -- AERL code test data
Chemical 1: Dichloromucktane
Run complete
EXAMS > PLOT KIN PL (1,4,0,0 — see PLOT command)
System: Pond — AERL code test data
Chemical: Dichloromucktane
2.00 IBB BBB
I B BBBB BBBB
I BBBB BBBB BBB
I B BBBB BBBB BB
I BB BBB
1 .33 I
I
I
I
I
0.667 I
I
I
I
I
O.'OOO I
+ + + + + + + + + + +
0.000 2.00 4.00 6.00 8.00 10.0
1.00 3.00 5.00 7.00 9.00
Time, Days
EXAMS > SET CINT=1
EXAMS > CONTINUE
Initial time for integration will be 10.0 Days
Enter ending time of integration, HELP, or EXIT > 30
Simulation beginning for:
Environment: Pond -- AERL code test data
Chemical 1: Dichloromucktane
Run complete.
EXAMS > SET CINT=10
EXAMS > ZERO PULSE LOAD
EXAMS > CONTINUE
16
-------
Initial time for integration will be 30.0 Days
Enter ending time of integration, HELP, or EXIT > 90
Simulation beginning for:
Environment: Pond — AERL code test data
Chemical 1 : Dichloromucktane
Run complete.
EXAMS > PLOT KINETIC PLOT (1,4,0,0)
System:
Chemical:
3.49
2.33
1 .16
0.000
Pond — AERL code test data
Dichloromucktane
I B
I BB
I BB
I B
I BB
I BB
IB BB
I BBB BBB
I BBB
I BB B
I B
I B
I B B 1
I
I
I
0.000 18.0 36.0 54.0 72.0 90.0
9.00 27.0 45.0 63.0 81.0
Time, Days
These commands show the use of the CONTINUE command in Mode 2.
The objective of the analysis was to introduce two pulses of
chemical separated by ten days and to follow exposure over 90
days. Note the phased increase in the Communications INTerval
CINT from 0.25 to 1 and then 10 days. Note the use of the ZERO
command to clear the pulse load ADB before the simulation of
dissimilation from day 30 through day 90. If this were not
done, EXAMS would introduce an additional pulse on day 30.
2. EXAMS > SET MODE=3
EXAMS > SHO TI FR
A RUN will integrate from 1 January 1985
through 31 December 1985.
(YEAR1 = 1985, and NYEAR = 1.)
EXAMS > RUN
17
-------
Simulation beginning for:
Environment: Pond — AERL code test data
Chemical 1: Dichloromucktane
Run complete.
EXAMS > SHO TI FR
A RUN will integrate from 1 January 1985
through 31 December 1985.
(YEAR1 = 1985, and NYEAR = 1.)
CONTinuation will proceed through 31 December 1986
(NYEAR = 1.)
EXAMS > SET NYEAR=3
EXAMS > SH TI F
A RUN will integrate from 1 January 1985
through 31 December 1987.
(YEAR1 = 1985, and NYEAR = 3.)
CONTinuation will proceed through 31 December 1988
(NYEAR •= 3.)
EXAMS > CONTINUE
CONTinuing integration through 31 December 1988.
Simulation beginning for:
Environment: Pond -- AERL code test data
Chemical 1: Dichloromucktane
Run complete.
EXAMS >
These commands illustrate the use of the CONTINUE command in
Mode 3. SHOW TIME FRAME is used to assess the state of the
integrator timer controls.
18
-------
DESCRIBE
Reports the data type, dimensionality, and implemented size of parameters
Related:
Control variables:
Commands: HELP
Syntax:
DESCRIBE parameter
Parameters:
Any "system parameter" -- any chemical or environmental
input datum, control parameter (e.g., MODE, CINT), etc.
Prompt:
Options:
Enter SYSTEM PARAMETER name >
Any parameter accessible to the CHANGE and SET commands can be
inspected using the DESCRIBE command.
Description:
The DESCRIBE command returns information about EXAMS' input
data and control parameters. All variables whose values can be
altered using the CHANGE and SET commands can be inspected by
the DESCRIBE command. The information returned by DESCRIBE
includes the data type (real, integer, character), dimension-
ality (scalar, vector, matrix (2-dimensional), table (3-dimen-
sional matrix)) and implemented size in the version of EXAMS in
use. The DESCRIBE command is the first recourse when a CHANGE
or SET command fails.
Example s:
1. EXAMS > DESR MODE
Command not recognized. Type HELP for command information.
EXAMS > DESCR
Enter SYSTEM PARAMETER name > MODE
MODE is an Integer Scalar.
These commands establish that "MODE" is an integer scalar. Note
that the initial typing error (DESR) resulted in a "not recog-
nized" error message followed by return to the EXAMS prompt.
19
-------
2. EXAMS > CHANGE VOL(27) TO 7E5
Subscript out-of-range.
EXAMS > DESCRIBE VOL
VOL is a Real Vector with 25 elements.
This command reports that VOL is a real variable, with 25
elements. In this example, the number of segments (NPX) in the
version of EXAMS currently in use is set for 25 at most. Any
(intentional or accidental) attempt to set "KOUNT" to a value
>25, or to enter a value for the VOLume of a segment >25 (e.g.,
VOL(27)) will fail, as illustrated above. DESCRIBE can be used
to check the reason for a failure of the CHANGE or SET command
when a problem with dimension sizes is suspected.
3. EXAMS > DESCRIBE QUANT
QUANT is a Real Table with dimensions (3,7,4)
EXAMS > HELP QUANT
QUANT is a Real Table with dimensions (3,7,4)
QUANTum yield (form,ion,chemical) Units: dimensionless
Reaction quantum yield for direct photolysis of chemicals
-- fraction of the total light quanta absorbed by a chemi-
cal that results in transformations. Separate values (21)
for each potential molecular type of each chemical allow
the effects of speciation and sorption on reactivity to
be specified in detail. The matrix of 21 values specifies
quantum yields for the (3) physical forms: (1) dissolved,
(2) sediment-sorbed, and (3) DOC-complexed; of each of (7)
possible chemical species: neutral molecules (1), cations
(2-4), and anions (5-7). (QUANT is an efficiency.)
These commands report the data type and dimensionality of
EXAMS' input "QUANT" (result of "DESCRIBE QUANT") and then
report the meaning of the dimensions and the physical units of
the variable (result of "HELP QUANT"). The local implementation
of EXAMS used in this example has the capacity to simulate the
behavior of no more than four chemicals simultaneously. Thus,
QUANT was DESCRIBEd as consisting of a set of four matrices,
each of (fixed) size (3,7).
20
-------
D O
Executes a command procedure; requests that EXAMS read subsequent input from
a specific file.
Related:
Control variables:
Commands:
AUDIT
Syntax:
Prompt:
Parameters:
Description:
DO file-spec
Enter filespec, HELP, or EXIT >
file-spec
Specifies the file from which to read a series of EXAMS
commands. If you do not specify a file type, the system
uses a default file type of EXA. Wild cards are not
allowed in the file specification.
Use command procedures to catalog frequently used sequences
commands. An EXAMS command procedure can contain:
of
o Any valid EXAMS command. The command line can include all
the necessary options and data to build a complete
command (exception: kinetic plots).
o Parameters or response options for a specific command.
When the currently executing command requires additional
parameters, the next line of the command file is searched
for apropriate input.
o Data. When the currently executing command requires
numerical or character data entry, the next line of the
command file is searched for input.
o Comment lines. Any line that contains an exclamation
point (!) or asterisk (*) in column one is ignored by
EXAMS' command interpreter. These lines can be used as
needed to document the command procedure.
Command procedures must not contain a request to execute
another command procedure. In other words, a DO file must not
contain a DO (@) command: EXAMS' DO commands cannot be nested.
Command procedures can be contructed as external files using
your favorite editor, or they can be contructed interactively
through the EXAMS system command processor, as illustrated
below. The default file type is .EXA, but files of any type
(suffix) can be used if the entire file name is specified when
entering the DO command.
21
-------
Examples:
1. EXAMS > AUDIT ON
All input will now be copied into the file
named AUDOUT.DAT on Fortran unit number 4
EXAMS > RECALL
Enter ENVIRONMENT, CHEMICAL, LOAD, PRODUCT,
HELP or EXIT > ENV
Enter environment No. or EXIT > 2
Selected environment is: Phantom Inlet
EXAMS > RECALL CHEM 2
Selected compound is: Dichloromucktane
EXAMS > RECALL LOAD 2
Selected load is: Aedes spray drift
EXAMS > ! LOAD 2 is the Phantom Inlet salt marsh study
EXAMS > SET KCHEM TO 2
EXAMS > RECALL CHEM 4 AS 2
Selected compound is: Tetrabromochickenwire
EXAMS > AUDIT OFF
These commands build a file (AUDOUT.DAT) that can later be used
as a command file upon entering the EXAMS system. In this
instance, the file could be renamed (e.g., SETUP.EXA) and used
to execute the above series of commands as a unit:
EXAMS > DO SETUP
or
EXAMS > @SETUP
The command file appears as follows:
RECALL
ENV
2
RECALL CHEM 2
RECALL LOAD 2
! LOAD 2 is the Phantom Inlet salt marsh study
22
-------
SET KCHEM TO 2
RECALL CHEM 4 AS 2
AUDIT OFF
Note that command files that are constructed interactively will
include "AUDIT OFF" as the final instruction. This can, of
course, be removed by editing the file if it is undesirable.
2. EXAMS > DO
Enter filespec, HELP, or EXIT > HELP
The "DO" or "@" command provides a means of executing
stored EXAMS commands. In response to the prompt, enter
the name of the file that contains the stored commands. A
filename extension of .EXA is supplied if one is not
explicitly specified.
Enter filespec, HELP, or EXIT > AUDOUT.DAT
EXAMS/DO > ! Audit trail of input sequence from EXAMS.
EXAMS/DO > RECALL
Enter ENVIRONMENT, CHEMICAL, LOAD, PRODUCT, HELP or EXIT >
EXAMS/DO > ENV
Enter environment No. or EXIT >
EXAMS/DO > 2
Selected environment is: Phantom Inlet
EXAMS/DO > RECALL CHEM 2
Selected compound is: Dichloromucktane
EXAMS/DO > RECALL LOAD 2
Selected load is: Aedes spray drift
EXAMS/DO > ! LOAD 2 is the Phantom Inlet salt marsh study
EXAMS/DO > SET KCHEM TO 2
EXAMS/DO > RECALL CHEM 4 AS 2
Selected compound is: Tetrabromochickenwire
EXAMS/DO > AUDIT OFF
The AUDIT option has been terminated.
This command requests execution of the command procedure con-
structed in Example 1 above. The default name (AUDOUT.DAT) was
not altered, so the complete file specification was given to
the DO command as the entry parameter. The DO file transfers a
set of 2 chemicals, an environmental model, and a load pattern
from the stored UDB to the ADB for further study and analysis.
23
-------
ERASE
Deletes, by access number, the data stored at a single sector of a User
Database (UDB) library (chemical, environmental, loadings, product chemistry).
Related: Control variables:
Commands: CATALOG, RECALL, STORE
Syntax: ERASE option access-number
Options
CHEMICAL
ENVIRONMENT
LOAD
PRODUCT
Prompt: Enter ENVIRONMENT, CHEMICAL, LOAD, PRODUCT, HELP or EXIT >
Options: CHEMICAL
Deletes the contents, by entry access number, of chemical
databases currently in the User Database. Each entry
corresponds to a single chemical, and contains the labora-
tory data describing ionization and (species-specific)
partitioning and reaction kinetics.
ENVIRONMENT
Deletes the contents, by entry access number, of environ-
mental databases currently in the User Database. Each
entry contains a canonical physical and chemical model of
an aquatic system, including the environmental data needed
to compute the reactivity and transport of synthetic
chemicals in the system.
LOAD
Deletes the contents, by entry access number, of chemical
loading patterns stored in the User Database. These data
include monthly values (kg/hour) for streamloads, non-
point-source loads, groundwater seepage loadings, precipi-
tation loads, and drift loads of chemicals entering the
aquatic environment, plus the magnitude (kg), target
environmental sector, and scheduling (month and day) of
chemical pulse loads.
24
-------
PRODUCT
Deletes the contents, by entry access number, of chemical
product data stored in the User Database (UDB). These
data include the Activity Database numbers of reactants
and products, the number code of the chemical process, and
(mole/mole) yield efficiencies as an (optional) function
of temperature.
Description: ERASE deletes the contents of a single sector of the specified
User Database (UDB) library (chemical, environmental, loads, or
product chemistry). The data to be deleted are selected
by choosing the appropriate access number. (If you work in a
mulit-user environment, be sure to avoid erasing others' data!)
Examples:
1. EXAMS > ERASE ENV 20
Environment 20 erased.
This command erases the data stored at Environmental UDB sector
number twenty. The space is now available for storage of
another dataset.
2. EXAMS > ERASE
Enter ENVIRONMENT, CHEMICAL, LOAD, PRODUCT, HELP or EXIT >
HELP
The ERASE command supports the following options
1. ENVIRONMENT,
2. CHEMICAL,
3. LOAD,
4. PRODUCT,
5. HELP (this option), or
6. EXIT.
Enter ENVIRONMENT, CHEMICAL, LOAD, PRODUCT, HELP or EXIT >
LOAD
Enter load No. or EXIT > 10
Load 10 erased.
This command erases the data stored at Loadings UDB sector
number ten. The space is now available for another dataset.
25
-------
EXIT
Use EXIT to abort a command in progress or to end an interactive session,
Related: Control variables:
Commands: QUIT
Syntax: EXIT
Prompt: None
Options: None
Description: The EXIT command terminates processing of the current command
procedure. If EXIT is used in response to an EXAMS command
option, control is returned to the EXAMS prompt command level.
If EXIT is entered from the EXAMS prompt command level, control
is returned to your computer's operating system.
Examples:
1. EXAMS > AUDIT
The following AUDIT options are available:
ON - invokes the AUDIT option
OFF - terminates the AUDIT option
HELP - this message.
EXIT - return to the Exams prompt.
AUDIT > EXIT
EXAMS >
This command terminates processing of the A^DIT command and
returns control to the EXAMS prompt command level. The current
status of AUDIT is not altered.
2. EXAMS > EXIT
This command terminates an interactive EXAMS session.
26
-------
HELP
Displays, on the terminal, information available in EXAMS' help files. EXAMS
provides descriptions of its commands, input data, control parameters, and
general concepts and analysis procedures.
Related:
Control variables:
Commands: DESCRIBE
Syntax:
HELP [keyword]
Prompt:
None
Keyword:
Specifies
you want.
a keyword or topic that indicates what information
None — if HELP is typed with no keyword, EXAMS lists the
keywords that you can specify to obtain information about
other topics.
Topic-name — describes either a basic EXAMS command, an
information page, or a "system parameter." System param-
eters include chemical and environmental input data,
system control parameters (e.g., CINT), and parameters
that control the current analysis (e.g., IMASS).
Ambiguous abbreviations result in a failure to achieve a
match on the keyword, and an error message is displayed.
Description:
The HELP command provides access to EXAMS' collection of on-
line user aids and information texts. This material includes:
Brief discussions of the syntax and function of
EXAMS' command words (RECALL, RUN, etc.)
each of
Definitions, physical dimensions, and meanings of sub-
scripts for EXAMS' chemical and environmental input data
and control parameters.
A series of information pages providing orientation to the
concepts implemented in the EXAMS program, the range of
capabilities and analyses that can be executed with the
27
-------
program, and brief expositions on data structures and
program control options.
Examples:
1. EXAMS > HELP
Available commands and information pages:
•
HELP message text and list of command and information
. topics
Issuing the HELP command without any keywords produces a list
of the HELP topics available in EXAMS main command library.
If you type in one of the topics on the list, EXAMS will
display a HELP message on that topic, and a list of subtopics
(if there are any).
2. EXAMS > HELP QUOIT
No information available for this request.
EXAMS >
When you request information for a topic not in EXAMS' files,
EXAMS displays a message to that effect and returns you to the
EXAMS > prompt.
3. EXAMS > HELP QUANT
QUANT is a Real Table with dimensions(3,7,4)
QUANTum yield (form,ion,chemical) Units: dimensionless
Reaction quantum yield for direct photolysis of chemicals
-- fraction of the total light quanta absorbed by a chemi-
cal that results in transformations. Separate values (21)
for each potential molecular type of each chemical allow
the effects of speciation and sorption on reactivity to
be specified in detail. The matrix of 21 values specifies
quantum yields for the (3) physical forms: (1) dissolved,
(2) sediment-sorbed, and (3) DOC-complexed; of each of (7)
possible chemical species: neutral molecules (1), cations
(2-4), and anions (5-7). (QUANT is an efficiency.)
You can Request information about any input datum (chemical,
environmental, control parameters, analysis parameters) acces-
28
-------
sible to the CHANGE and SET commands. EXAMS then displays on
the screen the characteristics of the variable (equivalent to
the results of DESCRIBE), followed by a discussion of the
variable that echoes the entry in the Glossary section of your
EXAMS User Manual.
29
-------
LIST
Displays an EXAMS output table on your terminal,
Related:
Control variables: FIXFIL
Commands: PLOT, PRINT
Syntax:
LIST option
Options
table-#
ALL
HELP
Prompt:
Table > option
Options:
table-# specifies the number of an EXAMS output table to be
displayed.
ALL
Sequential display of all current output tables.
HELP
Displays a list of titles of EXAMS output tables.
Description:
The LIST command displays EXAMS' output tables at your
terminal. When the LIST command displays output, you can
control the display in several ways:
o To temporarily halt the output and resume it at the line
where it was interrupted, use CTRL/S followed by CTRL/O.
o To suppress the display but continue processing the LIST
command, use CTRL/O. If you press CTRL/O again before the
command terminates, output resumes at the current point in
the processing of the LIST command.
When you request a primary table number (that is, an integer
from 1 to 20) EXAMS displays the first table of that number
present in the analysis file. If additional tables of that type
are present in the file, EXAMS will display the first, and
then search for more tables of that type and, if any are found,
ask if you want to see them.
30
-------
Examples:
1. EXAMS > LIST
A PRINT, LIST, or PLOT command was issued before executing
a RUN. If results exist from a previous simulation, these
can be accessed after issuing the command:
SET FIXFIL TO 1
EXAMS > SET FIXFIL TO 1
EXAMS > LIST
Table > HELP
1 Chemical inputs: FATE Data
2 Chemical inputs: PRODUCT Chemistry
3 PULSE Chemical Loadings
' 18 Sensitivity Analysis of Chemical FATE
19 Summary TIME-TRACE of Chemical Concentrations
20 Exposure Analysis SUMMARY
ALL Entire Report
Table > 18
Ecosystem: Name of Waterbody
Chemical: Name of chemical
TABLE 18.01. Analysis of steady-state fate ...
•
(body of table)
The LIST command requests that output Table 18 from an EXAMS
results file be displayed on the terminal. For illustrative
purposes, it was assumed that the user had left EXAMS and then
returned to inspect Table 18 generated in the previous session.
2. EXAMS > LIST 20
Ecosystem: Name of Waterbody
Chemical: Name of FIRST chemical
31
-------
TABLE 20.01. Exposure analysis summary: 1983—1985.
(body of table)
More ? (Y/N/Q) > Y
Ecosystem: Name of Waterbody
Chemical: Name of SECOND chemical
TABLE 20.02. Exposure analysis summary: 1983—1985,
(body of table)
In this example, EXAMS was used to investigate the behavior of
two chemicals over a period of several years, using Mode 3
simulations. The analysis began with year 1983, and NYEAR was
set to 3 to produce an analysis of the period 1983 through 1985.
The LIST command requests that all versions of Table 20 in the
analysis file be displayed, with a pause between each for
inspection of the results. In the example, the analyst chose
to examine the output for both chemicals. If the analysis is
now CONTINUEd, the current set of tables will be replaced with
new results. The PRINT command should be used to make copies
of all intermediate results you want to save.
The sub-table numbers of EXAMS' output tables identify the ADB
number of the chemical, the number of any ionic species (see
SPFLG in the Glossary), and the month of the year, as follows.
Table Sub-tables
1 1 .cc.i
4-6, 8, NN.mm
10,1 1 ,13
12 1 2.cc.mm
14 (Mode 1/2) 14. cc
14 (Mode 3) 14.cc.mm
15-18,20 NN.cc
Examples
1 .01 .1
4.01
10.13
12.01 .12
14.01
14.01 .12
18.01
20.01
Sub-table Meaning
Table . chemi ca 1
Table. month
(13= annual
Table. chemical
Table. chemical
Table. chemical
Table . chemi ca 1
.ion
mean)
.month
.month
32
-------
NAME
Use the NAME command to attach unique names to datasets.
Related:
Syntax:
Prompt:
:
Control Variables: MCHEM
Commands: CATALOG, ERASE, STORE, RECALL
NAME IS aaa... (up to 50 characters)
where can be CHEM, ENV, LOAD, or PRODUCT
Options available are:
HELP - this message.
EXIT - return to EXAMS command mode.
- this message
- considered to be a new name.
NAME >
EXAMS uses these four kinds of datasets:
1. CHEMICAL reactivity and partitioning,
2. ENVIRONMENTal physico/chemical parameters,
3. allochthonous chemical LOADings, and
4. PRODUCT chemistry for generating interconversions
among multiple chemicals in an analysis
Description:
Examples:
The NAME command is used to associate unique names with datasets
in the UDB. These names can be STOREd in the CATALOGS; they are
printed in the headers of EXAMS' output tables. When naming
CHEMICAL datasets, the ADB number of the chemical to be named is
given by MCHEM; use "SET MCHEM TO n" before naming chemical
dataset "n".
1
EXAMS > CHEM NAME IS Tetrachlorochickenwire
The NAME command associates the name "Tetrachloro..." with the
chemical data in the sector of the activity database (ADB) given
by the current value of MCHEM. This name will be printed on all
subsequent appropriate output tables, and it will be used as a
title for the database if the STORE command is used to download
the data into the User Database (UDB).
33
-------
2. EXAMS > SET MCHEM = 2
EXAMS > CHEM NAME IS Dichloromucktane
The chemical name command always addresses the MCHEM sector of
the chemical ADB, thus, this example names chemical number 2 to
"Dichloro...".
3. EXAMS > ENVIR NAME IS Pogue Sound
This command names the current environmental dataset "Pogue
Sound". The name will now appear on output tables, and remain
with the dataset if it is downloaded to the UDB permanent files.
34
-------
PLOT
Used to plot character graphics for the chemical state of the ecosystem.
Related:
Control Variables: MCHEM
Commands: LIST, PRINT
Syntax:
Prompt:
PLOT [Option!, Option2, OptionS]
Options:
POINT
PROFILE
KINETIC
The following options are available:
POINT - Vertical concentration profile
PROFILE - Longitudinal concentration profile
KINETIC - List or plot kinetic outputs
HELP - This message
EXIT - Return to the EXAMS prompt
Option >
Plot options: POINT
"POINT" plots are generalized profiles of chemical concentra-
tions. These also require selection of a variable to be dis-
played (total concentration, dissolved concentration, etc.)
and a "statistical" class (average values, minima, or maxima).
PROFILE
"PROFILE" plots are longitudinal profiles of chemical concen-
trations. These require selection of a concentration variable
(total concentration, dissolved concentration, etc.) and an
environmental sector (water column or benthic sediments). The
abscissa of the resulting plot is set up by increasing segment
number, which in most cases should represent an upstream-down-
stream progression. When the aquatic model includes both lon-
gitudinal and vertical segmentation, each section of the plot
begins at the air-water or water/benthic interface and proceeds
vertically downward (the bars are presented along the abscissa).
35
-------
KINETIC
"KINETIC" plots display the results of integration of the
governing equations over the time spans selected for simula-
tion. These plots also require selection of concentration
variables and either particular segments, or summary "statis-
tics," for display. The first numerical parameter selected
is used as the abscissa for the plot; all further selections
plot on the ordinate.
Description: Use the PLOT command to display results of the current analysis.
Three kinds of character-graphic PLOTs are available on-line
from EXAMS: POINT, PROFILE, and KINETIC. Each PLOT requires the
specification of several options; these can either be entered on
the system command line or entered in response to EXAMS' prompts.
The available second- and third-level options are illustrated in
the examples below. The results available to POINT and PROFILE
plots depend on the Mode used in the simulation. In Mode 1, the
outputs are steady-state concentrations. In Mode 2, the results
are a snap-shot of concentrations as of the end of the current
temporal simulation segment. In Mode 3, the results are time-
averaged concentrations over the most recent temporal simulation
segment of length NYEAR.
Example s:
1. EXAMS > PLOT POINT
The following concentration options are available:
TOTAL - mg/L in Water Column,
mg/kg in Benthic Sediments
DISSOLVED - "Dissolved" (mg/L)
(aqueous + complexes with "dissolved" organics)
PARTICULATE - Sediment-sorbed (mg/kg)
BIOTA - Biosorbed (ug/g)
MASS - Chemical mass as grams/square meter AREA
HELP - This message
EXIT - Return to the EXAMS prompt
Option > DISSOLVED
The following statistical options are available:
MAX - Maximum concentration
MIN - Minimum concentration
AVE - Average concentration
MINMAX - For simultaneous plot of maxima and minima
HELP - This message
EXIT - Return to the EXAMS prompt
36
-------
Option > AVERAGE
9.00E-04 -I
I
I AAAAAAAAAAA
I A|
C I A
O 8.00E-04 -I A
N I A
AC I A
V E I A
EN I A
R T 7.00E-04 -I A
A R I A
G A I A
E T I A
I I A
O 6.00E-04 -I A
N I A
I A
I A
I A
D
I
S
S
0
L
V
E
D
M
G
/
/
L
A
A
A
A D
A I
A S
A S
A 0
A L
A V
A E
A D
A
A M
A AAAAAGAAAAA
A A ,
A A 1
1 A
A
5.00E-04 -+_AAAAAAAAAAA_AAAAAAAAAAA
Water Col Benthic
EXAMS > SET MCHEM=2
EXAMS > PL PO DI AV
4.00E-04
C
O
N
A C
V E
E N
R T
A R
G A
E T
I
0
N
3.50E-03
3.00E-03
2.50E-03
2.00E-03
I
I
I
I
I
I
I
I
I
I
I
I
D
I
S
S
O
L
D
I
S
AAAAASAAAAA
A
A
I AAAAAVAAAAA A
I A
I A
I A
I A
I A
I A
I A
E
D
M
G
/
L
A A
A A
A A
A A
A A
A A
A A
O
L
V
E
D
M
G
/
L
A
A
A
A
A
A
A
A
A
A
+ AAAAAAAAAAA AAAAAAAAAAA
Water Col Benthic
37
-------
This example illustrates EXAMS' internal prompting for POINT
plots. Note that the analysis included two chemicals; the plot
for chemical number two was obtained by first SETting MCHEM=2.
The second plot was requested via a single command line, thus
bypassing the PLOT prompts.
C
T O
O N
T C
A E
L N
T
M R
G A
/ T
L I
0
N
8.00E-01
6.00E-01
4.00E-01
2.00E-01
2. EXAMS > PLOT PROF
The following concentration options are available:
TOTAL - mg/L in Water Column,
mg/kg in Benthic Sediments
DISSOLVED - "Dissolved" (mg/L)
(aqueous + complexes with "dissolved" organics)
PARTICULATE - Sediment-sorbed (mg/kg)
BIOTA - Biosorbed (ug/g)
MASS - Chemical mass as grams/square meter AREA
HELP - This message
EXIT - Return to the EXAMS prompt
Option > TOTAL
The following options are available:
WATER - Water Column concentrations
SEDIMENTS - Benthic Sediment concentrations
HELP - This message
EXIT - Return to the EXAMS prompt
Option > WATER
O.OOE+00
I
I
I
I
I
I
I
I
I
I
I ,
I
I 0-
I E
I 012 E
I 010 01 1 E E E
I 009 E E E E E E E
I 008 EEEEEEEEE
I 005 006 007 EEEEEEEEEEE
I 002 003 004 E E E E EJE EEEEEEEEEEE
+ 001 EEE EEE EEE EEE EEE EEE EEE EEE EEE EEE EEE El
WATER COLUMN
0'
H
H
3 H
E H
E H
E H
E H
E H
E H
E H
:E H!
0"
H
4 H
H H
H H
H H
H H
H H
H H
H H
H H
H H
H H
1H HP
5
H
H
H
H
H
H
H
H
H
H
H
H
1H
38
-------
The above example illustrates EXAMS' internal prompts for a
PROFILE plot. As with the POINT option, this entire command
could be entered on a single line:
EXAMS > PLOT PROF TO WAT
3. EXAMS > PLOT KIN
The following KINETIC options are available:
LIST - lists selected KINETIC output parameters
PLOT - plots selected KINETIC output parameters
HELP - this message
EXIT - return to the EXAMS prompt
Option > PLOT
Chemical: Methyl Parathion
Environment: Pond -- AERL code test data
Simulation units: Days
Number of segments: 2
1 2
Type of segment (TYPE): L B
The following parameters are available:
("Dissolved" = aqueous + complexes with "dissolved" organics.)
1 - Simulation time
2 - Water Column: average "dissolved" (mg/L)
3 - average sorbed (mg/kg)
4 - total mass (kg)
5 - Benthic: average "dissolved" (mg/L)
6 average sorbed (mg/kg)
7 total mass (kg)
Enter parameters, one per line;
enter 0 to end data entry and proceed.
Parameter > 1
Parameter > 4
Parameter > 7
Parameter > 0
The following parameters are available for each segment:
1 - Total concentration (Water Column, mg/L; benthic, mg/kg)
2 - "Dissolved" (mg/liter of fluid volume)
3 - Sorbed (mg/kg of sediment)
4 - Biosorbed (ug/g)
5 - Mass (grams/square meter of AREA)
39
-------
Enter segment-parameter number pair, one number per line;
enter 0 when data entry is complete; EXIT to abort.
Enter segment number > 0
System: Monthly pond — AERL code test data
Chemical: Methyl Parathion
0.160 I BB
I B
I BB B
I B
I B B
0.106 I B B
I B B
I B B
I B CCCC
I B CCB CCC
5.322E-02 I B CC B CCC
I BB B C BB CCC
I B CC B CCCC
I B B BC BB CCCCC
I BCCCCCCC BBBB CCCCCCCCCC
0.000 ICCCCCCCCCCCCCCCCBBCBBB BBBBBBBBBBBBBBBBBC
+ + + + + + + + + + +
0.000 73.0 146. 219. 292. 365
Time, Days
This example illustrates EXAMS' prompting in KINETIC plots.
The numerical options cannot be entered on the command line,
but must be entered in response to the prompts.
-------
PRINT
Use the PRINT command to queue an output table for hardcopy printing.
Related: Control variables: FIXFIL
Commands: LIST
Syntax: PRINT option
Options:
table-#
ALL
HELP
Prompt: Table >
Options: table-# specifies the number of an EXAMS output table to be
displayed.
ALL
Sequential printing of all current output tables.
HELP
Displays a list of titles of EXAMS output tables.
Description: The PRINT command transfers EXAMS results tables to an output
queue for printing. The command functions identically with the
LIST command, except that output is saved for hardcopy printing
rather than being routed to your interactive terminal. If the
PRINT command results in output at your terminal, you may need
to consult with site ADP personnel to properly direct the print
stream to a lineprinter.
Examples: See the documentation for the LIST command.
41
-------
QUIT
Use QUIT to end an interactive EXAMS session.
Related:
Syntax:
Prompt: None
Options: None
Description:
Control variables:
Commands: EXIT
QUIT
Enter QUIT at the EXAMS prompt command level in order to termi-
nate the interactive session. Control is returned to your
computer's operating system.
Example s:
1. EXAMS > QUIT
This command terminates an interactive EXAMS session.
42
-------
RECALL
Use RECALL to upload data from the permanent database (UDB) into current
foreground memory (ADB).
Related: Control Variables: MCHEM
Commands: CATALOG, ERASE, NAME, STORE
Syntax: RECALL UDB# [AS ADB#]
Prompt: Enter ENVIRONMENT, CHEMICAL, LOAD, PRODUCT, HELP or EXIT >
Command parameters:
can be CHEMICAL, ENVIRONMENT, LOAD, or PRODUCT
(EXAMS uses these four kinds of datasets.)
AS ADB# is an optional explicit specification of MCHEM
(see Example 1).
UDB# specifies the accession number or location in the User
Database for the source data for transfer to the ADB
(Example 2).
Description: RECALL transfers data from permanent storage (UDBs) to activity
databases (ADBs ). The data in active use by EXAMS are held in
a foreground memory bank (Activity DataBase or ADB) with four
sectors, one for each datatype required by EXAMS:
CHEMICAL reactivity and partitioning,
ENVIRONMENTal physico/chemical parameters,
allochthonous chemical LOADings, and
PRODUCT chemistry for generating interconversions
among multiple chemicals in an analysis.
When EXAMS is started, the ADB is empty. Use the RECALL
command to transfer data from the permanent User Databases
(UDBs) to foreground memory (ADB).
When an analysis session is ended (QUIT or EXIT), ADBs are
discarded. Use the STORE command to transfer new data from
the ADB to the UDB sector of the same datatype for permanent
retention of the data.
43
-------
Examples:
1 . Because EXAMS can process several chemicals in a single
analysis, the target sector of the chemical activity database
should be specified when using the RECALL command to activate
CHEMICAL data. (This section of the command should be omitted
for other data types.) When the ADB# (an integer between 1
and KCHEM) is omitted, the chemical data is transferred to the
sector of the activity database given by the current value of
MCHEM. For example, to activate data from the chemical UDB,
putting UDB dataset number 9 into ADB sector 1 , and UDB #14
into sector 2:
Either:
EXAMS > SET MCHEM TO 1
EXAMS > RECALL CHEMICAL 9
EXAMS > SET MCHEM TO 2
EXAMS > RECALL CHEMICAL 14
or, eguivalently:
EXAMS > RECALL CHEMICAL 9 AS 1
EXAMS > RECALL CHEMICAL 14 AS 2
2. Long-term retention of data required by EXAMS is provided
by storage in the "User Database" (UDB, generally resident on
a physical device—e.g., a hard disk) for CHEMICALS, ENVIRON-
MENTS, LOADs, or PRODUCTS. Within each of these UDB sectors,
each dataset is CATALOGed via a unique accession number (UDB#).
When transferring data to foreground memory (the activity
database or ADB) from a UDB, the source location must be
specified by the name of the UDB sector and the accession
number within the sector. For example, to RECALL an
environmental dataset:
EXAMS > RECALL ENVIR 2
Selected environment is: Phantom Inlet, Bogue Sound
EXAMS >
44
-------
RUN
The RUN command begins a simulation analysis,
Related:
Control Variables: MODE
Commands: CONTINUE
Syntax:
Prompt:
RUN
None
Description:
Examples:
The RUN command executes an analysis and creates the output
files accessed by the LIST and PLOT commands. The activity
database (ADB) must be loaded, either via entry of new data or
by RECALL from the UDB, before a RUN can be initiated.
1. EXAMS > RECALL CHEMICAL 22
Selected compound is: Dibromomucktane
EXAMS > RECALL ENVIRON 17
Selected environment is: Albemarle Sound - Bogue Bank
EXAMS > SET STRL(1,1,13)=.01
EXAMS > RUN
Simulation beginning for:
Environment: Albemarle Sound - Bogue Bank
Chemical 1: Dibromomucktane
Run complete.
EXAMS >
In this example, a steady-state (MODE=1) analysis is conducted
by selecting a chemical and an environment, imposing a chemical
loading of chemical 1 on segment 1 under average conditions
(i.e., data sector 13, EXAMS initial default value) and invoking
EXAMS simulation models with the RUN command.
45
-------
SET
Used to specify the values of data in the activity database.
Related:
Commands: CHANGE (synonym), DESCRIBE, HELP
Syntax:
Prompt:
SET variable TO value
or
SET variable = value
CHANGE (VARIABLE TO VALUE) >
Variable: The data entry or variable to be SET can be specified either as
a single datum or, using wild cards (*), as an entire vector,
row/column of a matrix, etc.
Description:
Use the SET command to specify the values of data in the
activity database. "Value" can be any numerical quantity or
literal, as appropriate. "Variable" specifies an individual
element of input data or a program control parameter. Entire
vectors, rows/columns of matrices, etc. can be set to single
values using wild cards (*).
Examples:
1. EXAMS > SET VOL(27) TO 7E5
Subscript out-of-range.
EXAMS > DESCRIBE VOL
VOL is a Real Vector with 25 elements,
EXAMS> SET VOL(2) TO E
Invalid numeric quantity after TO.
EXAMS > SET VOL(2) TO 7E5
This command sets the environmental volume of segment 2 to
7.0E+05 cubic meters. The initial attempt to set the volume of
segment 27 was rejected by EXAMS because the version in use was
set up for environmental models of 25 segments at most. The
DESCRIBE command was used to check the number of subscripts and
46
-------
the dimensional size of the variable "VOL". The erroneous
entry of an alphabetic for the volume was trapped by the SET
command; the initial value of VOL(2) was not altered.
2. EXAMS > HELP TCEL
TCEL is a Real Matrix with 25 rows and 13 columns.
Temperature-CELsius (segment,month) Units: degrees C.
Average temperature of ecosystem segments.
Used (as enabled by input data) to compute effects of
temperature on transformation rates and other properties
of chemicals.
EXAMS > SET TCEL(2,7)=24
This command changes the July temperature in segment 2 to 24
degrees C. The HELP command was used to check subscript dimen-
sions, maximum values, the meaning of the subscripts (subscript
#1 denotes the segment, subscript #2, the month), and the
proper units for the input datum (Celsius degrees).
EXAMS > HELP POH
POH is a Real Matrix with 25 rows and 13 columns.
pOH (segment,month) Units: pOH units
The negative value of the power to which 10 is raised in
order to obtain the temporally averaged concentration of
hydroxide [OH-] ions in gram-molecules per liter.
EXAMS > SET POH(*,13) TO 6.2
This command sets the average pOH (sector 13) of every segment
to 6.2. Note use of wild card "*" to specify that all segments
are to be changed. As in the previous example, HELP was used
to check subscript dimensions, units, etc. This step, of
course, is optional.
47
-------
SHOW
Use SHOW to display current data values or control settings.
Related: Control Variables: MCHEM, MONTH
Commands: CHANGE, SET
Syntax: SHOW option [range]
Prompt: The following options are available:
Advection, Chemistry, Geometry, Globals,
Loads, Plot, Pulse Loads, Products
Quality, Time Frame, Turbulence, Variables
HELP, or EXIT >
Command parameters:
Range: Some options of the SHOW command accept the specification
of a range of values to define the scope of the data to be
displayed (see Example 1). Use MCHEM to delimit the range of
SHOW Chemistry, and MONTH for Geometry, Quality, etc.
Options:
ADVECTION
SHOW ADVECTION gives the advective hydraulic flow structure of
the current aquatic system. A single element in a dataset might
typically look like:
J_FR AD 1 J FRom ADvection: Source Segment
I_TO_AD 3 I_TO ADvection: Terminus
ADV_PR 1.00 ADVection_Proportion: Percent
of total JFRAD flow on path
Path No.: 1 Vector index for SETting data
No more than NCON hydrologic pathways can be specified. If more
are needed, this number can be increased and EXAMS recompiled.
Specify export pathways by entering a zero (0) for the number of
the segment to receive the flow (ITOAD). Do not specify a
hydrologic source term by entering zero in the JFRAD vector;
instead use streamflows, non-point-source flows, etc.
48
-------
CHEMISTRY
SHOW CHEMISTRY displays the chemical output data currently in
the ADB (foreground memory bank). The sector of the ADB denoted
by the current value of MCHEM is displayed. Within each sector
of the ADB (that is, for each chemical under active review), the
data for each ionic species are presented separately, and
photochemical data are presented on separate screens.
GEOMETRY
SHOW GEOMETRY returns a segment-by-segment description of the
geometry (volumes, areas, etc.) of the current ecosystem. The
segment number reported with each block of data is the first
subscript for modifying the datum using CHANGE or SET. The
month to be displayed is set by the current value of MONTH
(explicit mean values are denoted by MONTH number 13): the month
is the second subscript of such data as WIND, STFLD, etc.
GLOBALS
SHOW GLOBALS displays the input data that are "global" in extent,
that is, "global" data apply to all segments of the current
ecosystem.
LOADS
SHOW LOADS displays the current state of allochthonous chemical
loadings. The form of the display depends on the current
operational MODE: initial values are ignored in Mode 1 as they
have no effect on the analysis results. The value of PRSW also
affects the display: when PRSW is 0, SHOW LOADS returns a summary
of annual loadings; when PRSW=1, a month-by-month tabulation is
displayed as well. This display may not represent the final
values used in the analysis, because EXAMS will modify loads
that result in violation of the linearizing assumptions used to
construct the program. After a RUN has been executed, however,
SHOW LOADS will display the corrected values.
PRODUCTS
SHOW PRODUCTS displays the specifications for product chemistry
currently in the ADB. Each entry is identified and loaded
according to a unique "pathway number." A single element of a
dataset might look like this: '
CH_PAR 1 ADB number of CHemical PARent
T_PROD 2 ADB number of Transformation PRODuct
49
-------
N_PROC 7 Number of transforming PROCess
R_PORM 29 Reactive FORM (dissolved, etc.)
YIELD M/M 0.100 Mole/Mole YIELD of product
EaYLD Real 0.000 Enthalpy of yield (if appropriate)
Pathway: 1 Number of the pathway
More detail as to the numbering of NPROC and RFORM is given in
the Glossary, and can be accessed via the HELP command. No more
than NTRAN transformation pathways can be specified. If more
are needed, this parameter can be increased and EXAMS recompiled.
PLOT
SHOW PLOT examines the contents of the concentration time-series
and steady-state files, and reports the names of the chemicals
and ecosystem used in the analysis.
PULSE LOADS
SHOW PULSE LOADS displays'the specifications for allochthonous
pulses of chemicals entering the system. This display may not
represent the final values used in the analysis, because EXAMS
will modify loads that result in violation of the linearizing
assumptions used to construct the program. Although faulty
pulse loads are discarded, EXAMS does not correct the input
pulse load data, because the occurrence of load constraint
violations depends on the context (i.e., the magnitude of current
stream loadings, etc.). Thus, unlike SHOW LOADS, the SHOW PULSE
display following execution of a RUN does not display corrected
data. The pulses actually used during an analysis are instead
displayed in EXAMS' output tables, where they can be examined
using the LIST command.
QUALITY
SHOW QUALITY returns a segment-by-segment display of the
canonical water-quality data included in the current ENVironmen-
tal ADB dataset. The month to be displayed is set by the current
value of MONTH (explicit mean values are denoted by MONTH number
13). The month is the second subscript of such data as pH, pOH,
etc. The first subscript is the segment number; thus these data
are entered (CHANGE/SET) as "daturn(segment,month)".
TIME FRAME
SHOW TIME FRAME displays the current status of the parameters
needed to control the temporal aspects of a Mode 2 or Mode 3
simulation.
50
-------
TURBULENCE
SHOW TURBULENCE displays the input data describing dispersive
transport in the active (loaded in the ADB) ENVIRONMENTa1
dataset. The index vectors (JTURB, ITURB) define the existence
of inter-segment dispersive transport paths. A zero in either
vector, when paired with a non-zero value at the corresponding
position in the other index vector, is taken as a boundary
condition with an uncontaminated body of water. A single element
in a dataset might typically be displayed like this:
Segment number for dispersion
Segment number for dispersion
Cross-sectional area of path
CHARacteristic_Length of path
Eddy DiSPersion coefficient
Vector index for data entry
No more than NCON hydrologic pathways can be specified. If more
are needed, this number can be increased and EXAMS recompiled.
VARIABLES
SHOW VARIABLES displays a list of the names of EXAMS input data
and control parameters. These names must be used to SET/CHANGE,
SHOW values, HELP/DESCRIBE, etc.
J TURB
I TURB
XS" TUR m2
CHARL m
DSP m2/hr
Path No. :
1
2
5.000E+04
2.53
4.676E-05
1
Description:
Use the SHOW command to examine the current contents of the ADB,
that is, the foreground datasets used for the current analysis.
The SHOW command can be used to examine clusters of similar
data, the values of individual parameters, or the data contained
in entire vectors. Typing SHOW without an option will display a
list of the available options.
Examples:
1 . The SHOW command can be used to examine the value of a single
parameter. For example, the pH of segment 7 of the current
ecosystem during September could be inspected by entering:
EXAMS > SHOW PH(7,9)
Through the use of wild cards (*), the SHOW command can also be
used to display the data in an entire vector or row/column of a
data matrix. For example, the pH of all segments of the current
ecosystem during September could be displayed by entering:
EXAMS > SHOW PH(*,9)
and the pH of segment 7 through the year could be displayed by:
EXAMS > SHOW PH(7,*)
51
-------
STORE
Use STORE to download current (ADB) data into the permanent database (UDB;
Related:
Control Variables: MCHEM
Commands: CATALOG, ERASE, NAME, RECALL
Syntax:
Prompt:
STORE [ADB# IN] UDB#
Enter ENVIRONMENT, CHEMICAL, LOAD, PRODUCT, HELP or EXIT >
Command parameters:
Description:
Examples:
can be CHEMICAL, ENVIRONMENT, LOAD, or PRODUCT
(EXAMS uses these four kinds of datasets.)
ADB# IN is an optional explicit specification of MCHEM
(see Example 1).
UDB# specifies the accession number or location in the User
Database for storage of the current ADB sector (Example 2).
STORE downloads data from activity databases (ADBs) into the
permanent User DataBases (UDBs). The data in active use by
EXAMS are held in a foreground memory bank (Activity DataBase
or ADB) with four sectors, one for each datatype required by
EXAMS:
CHEMICAL reactivity and partitioning,
ENVIRONMENTal physico/chemical parameters,
allochthonous chemical LOADings, and
PRODUCT chemistry for generating interconversions
among multiple chemicals in an analysis.
When an analysis session is ended (QUIT or EXIT), these data
are discarded. Use the STORE command to transfer data from the
ADB to the UDB sector of the same datatype for permanent
retention of the data.
1. Because EXAMS can process several chemicals in a single
analysis, the source sector of the chemical activity database
should be specified when using the STORE command to download
52
-------
CHEMICAL data. (This section of the command should be omitted
for other data types.) When the ADB# (an integer between 1 and
KCHEM) is omitted, the chemical data is taken from the sector
of the activity database given by the current value of MCHEM.
For example, to STORE data in the UDB, putting ADB sector 1
into the chemical UDB under catalog/accession number 9 and ADB
sector 2 into UDB sector 14:
Either:
EXAMS > SET MCHEM TO 1
EXAMS > STORE CHEMICAL 9
EXAMS > SET MCHEM TO 2
EXAMS > STORE CHEMICAL 14
or, equivalently:
EXAMS > STORE CHEMICAL 1 IN 9
EXAMS > STORE CHEMICAL 2 IN 1 4
2. Long-term retention of data required by EXAMS is provided
by storage in the "User Database" (UDB, generally resident on a
physical device—e.g., a hard disk) for CHEMICALS, ENVIRON-
MENTS, LOADs, or PRODUCTS. Within each of these UDB sectors,
each dataset is CATALOGed via a unique accession number
(UDB#). When transferring data between foreground memory (the
activity database or ADB) and a UDB, the target location must
be specified by the name of the UDB sector and the accession
number within the sector. For example, to STORE the current
environmental dataset:
EXAMS > STORE ENVIR 2
Environment record 2 is in use with
Pond — AERL code test data
Replace? > NO
Nothing changed.
EXAMS > STORE ENVIR 14
Environment stored: Phantom Inlet, Bogue Sound Study Data
EXAMS >
Note that EXAMS provides a measure of protection against
accidental overwriting of existing datasets, an important
courtesy in a multi-user environment.
53
-------
ZERO
Use the ZERO command to initialize (set to zero) loadings databases or the
concentration of pollutant chemicals throughout the ecosystem.
Related:
Control variables: MODE
Commands: CONTINUE, RUN
Syntax:
ZERO (option)
Options:
PULSE LOADS
LOADS
RESIDUALS
Prompt:
The following options are available:
Description:
Examples:
PULSE LOADS
LOADS
RESIDUALS
HELP
EXIT
ZERO >
zero all pulse loads,
zero all other loads,
zero all pollutant concentrations,
this message, or
return to command mode with no action.
The ZERO command initializes (sets to zero) the entire suite of
allochthonous chemical pulse loadings (IMASS), longer term load-
ings (stream loads, drift loads, etc.), or the current values of
pollutant chemical concentrations throughout the ecosystem. The
ZERO command is designed primarily for use during the course of
temporally segmented simulation studies. The same effect can be
achieved with multiple applications of the CHANGE/SET command;
ZERO is a block-mode implementation that reduces the work needed
to remove loadings datasets. (See Example 1 in the documentation
of the CONTINUE command.)
1. EXAMS > SET MODE=2
EXAMS > RECALL CHEMICAL 22
Selected compound is: Dibromomucktane
EXAMS > RECALL ENVIRON 17
Selected environment is: Albemarle Sound - Bogue Bank
EXAMS > SET STRL(1,1,13)=.01
54
-------
EXAMS > SET IMASS(1)=2.0
EXAMS > SET ISEG(1)=14
EXAMS > SET ICHEM(1)=1
EXAMS > RUN
Simulation beginning for:
Environment: Albemarle Sound - Bogue Bank
Chemical 1: Dibromomucktane
Run complete.
EXAMS > ZERO PULSE LOADS
EXAMS > CONTINUE
In this example, an initial-value (MODE=2) analysis is begun by
selecting a chemical and an environment, imposing an allochtho-
nous load of chemical 1 on segment 1 under average conditions
(i.e., data sector 13, EXAMS' initial default value), and speci-
fying the initial presence (or introduction at time zero) of 2.0
kg of material in segment 14. At the end of the initial RUN
segment, one might want to examine the output tables, plot the
results, etc. Then, before CONTINUing, the ZERO command is used
to remove the pulse load specifications. If this were not done,
EXAMS would introduce a second 2.0 kg pulse into segment 14 at
the beginning of the continuation segment. Alternatively, the
other loadings could have been removed, and the effect of a
series of pulse loads could be studied by issuing a sequence of
CONTINUE commands.
55
-------
GLOSSARY
ABSER
ABSolute ERror tolerance of integrators.
When the characteristics of the chemical and ecosystem are such as to
result in "stiff" equations, numerical errors may lead to small negative
numbers in the time series. If desired, the value of ABSER and RELER
can be decreased in order to achieve greater precision in the simulation
outputs.
ADB
Activity DataBase
EXAMS provides for long-term storage of CHEMical, Environmental, trans-
formation PRODuct chemistry, and allochthonous LOADings databases in a
User DataBase or UDB. The actual analyses are conducted on particular
datasets drawn from these files (or entered via SET/CHANGE). Particular
cases are loaded from the UDB into the foreground transient memory of
your computer in an Activity DataBase or ADB, using the RECALL command.
Because EXAMS simulates the behavior of several (MCHEM) chemicals simul-
taneously, the ADB for chemicals has MCHEM separate sectors. These data
are lost when you EXIT from EXAMS, so be sure to STORE any new or
corrected datasets before leaving EXAMS.
ABSOR
ABSORption spectra (wavelength, ion, chemical) Units: /cm/(mole/L)
Mean decadic molar light extinction coefficients in 46 wavelength
intervals over 280 — 825 nm. For wavelength "w" and chemical "c":
ABSOR (w, 1 , c) is absorption coefficient of SH^ (neutral molecule)
ABSOR(w,2,c) " " " " SH+ (1+ cation)
ABSOR (w, 3, c) " " " " SH2+ (2+ cation)
ABSOR(w,4,c) " " " " SH|+ (3+ cation)
ABSOR(w,5,c) " " " " SH~ (1- anion)
ABSOR (w, 6, c) " " " " SH2- (2- anion)
ABSOR (w, 7, c) " " " " S3- (3- anion)
56
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ADVPR
ADVection FRoportion (path) Units: n/a Range: > 0 - 1 .0
J>Roportion of flow ADVected from segment JFRAD that enters I TOAD. The
matching (same subscript) members of JFRAD, ITOAD, and ADVPR define an
advective hydrologic flow pathway. Although usually 1, ADVPR lets one
enter braided channels, etc. The total of ADVPRs for each segment must
sum to either 0 or 1, failing which, EXAMS aborts the RUN. The flow
data can be inspected by typina SHOW ADV; path numbers are given above
each active dataset. Enter data via CHANGE or SFT commands.
Additional information available: JFRAD, ITOAD
AFC
_Anion JBxchange Capacity (segment, month) Units: mea/100 g (dry)
Anion exchange capacity of sediment phase of each segment. Useful in
relating sediment sorption (partitioning) of anions to a variable
characteristic of system sediments.
AIRTY
AIR mass TYpe (month) Units: letter codes
Select: Rural (default), Urban, Maritime, or Tropospheric
AREA
AREA (segment) Units: m2
Top plan area of each model segment of the waterbody. For JJpilimnion
and Littoral secrments, AREA is the area of the air-water interface; for
Hypolimnion segments AREA is the area of the thermocline; for Benthic
segments it is the surface area of the bottom. In the latter case AREA
may differ from XSTUR in a dispersive exchanoe pair because of reduction
in exchanging area due to rock outcrops, etc.
ATURB
.Atmospheric TURBidity (month) Units: km
Equivalent aerosol layer thickness.
AUDOUT
While the AUDIT directive is in effect, a copy of user inputs and
responses is written to the file connected to FORTRAN Logical Unit Number
AUDOUT.
57
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BACPL
BACterioPLankton population density (segment, month) Units: cfu/mL
Population density of bacteria capable of degrading xenobiotics.
BNBAC
^eltfthic BACteria (segment, month) Units: cfu/1 OOg dry sediment
Population density of benthic bacteria that degrade xenobiotics.
BNMAS
BeNthic bioMASs (segment, month) Units: g(dry)/m2
Biomass of small benthos—infauna subject to biosorption.
BULKD
BULK Density (segment, month) Units: g/cm3
Fresh weight per unit volume of benthic sediments.
CEC
Cation Exchange Capacity (segment, month) Units: meq/100g (dry)
Cation exchange capacity of sediment phase in each segment. Useful in
relating sediment sorption (partitioning) of cations to a variable
characteristic of system sediments.
CHARL
CHARacteristic Length or mixing length (path) Units: m
Average of segment dimensions normal to the exchange interface linking
segment numbers JTURB(p) and ITURB(p) . The matching (same "p"
subscript) members of JTURB , ITURB, CHARL, DSP, and XSTUR together
define a dispersive transport pathway. A given segment may have
different mixina lenaths at different interfaces. CHARL can also be
calculated from the distance along a path that connects the centers of
segments JTURB ( p ) and ITURB (p) , passing through the interface whose area
is XSTUR (
See also: DSP, ITURB, JTURB, XSTUR
CHEMNA
CHEMical NAme(s) of compounds (50 characters,chemical) Units: n/a
Do NOT use "CHANGE" or "SFT" to enter names! The NAme for a CHEMical is
entered into the database via the command seguence:
-------
EXAMS > CHEMICAL NAME IS nnn...
where "nnn... " can include as many as 50 characters. This name is
associated with chemical library entries and is printed in the header
information of the appropriate output tables.
CHL
CHLorophylls + pheophytins (segment, month) Units: mq/L
Concentration of chlorophyll plus chlorophyll-like pigments. Used to
compute spectral light absorption coefficients due to pigments which
absorb light from the water column and thus compete with photolysis of
xenobiotics.
CHPAR
^CHemical PARent compound (path) Units: n/a Range: 1 - KCHEM
CHPAR(p) gives the ADB location of the parent source of TPROD(p). The
matching (same transformation path number "p") members of CHPAR and
TPROD give the location numbers in the active database of the parent
chemical and the transformation product for pathway "p". For example,
"SET CHPAR(p) TO 1", and TPROD(p) to 4, to show that the chemical in ADB
sector 4 is produced via transformation of the chemical in ADB sector 1,
via process data defined by the remaining members of product chemistry
sector "p".
See also: EAYLD, NPROC, RFORM, TPPOD, YIELD
CINT
Communications INTerval for dynamic simulations. Units: see TCODE
CINT is the interval between output cycles from the integrators. In
Mode 2, CINT can be set to produce any desired output freguency, so long
as the resulting reporting interval is _> 1 hour. When CINT is set to
0.0, EXAMS (Mode 2) sets CINT to report at the 12 egual-increment periods
most closely matching the duration specified by (TEND - TINIT). CINT is
under full user control only in Mode 2; in Modes 1 and 3 EXAMS itself
sets the value of CINT according to the needs of the analysis.
CLOUD
CLOUDiness (month) Units: dimensjonless Range: 0 — 10
Mean monthly cloudiness in tenths of full sky cover.
DEPTH
DEPTH (segment) Units: m
Averaae vertical depth of each segment.
59
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DFAC
Distribution FACtor (segment, month) Units: dimensionless ratio
Ratio of optical path length to vertical depth, range 1.0-2.0. A
vertical light beam has a DFAC of 1.0; a fully diffused light field has
a DFAC of 2.0. For whole days, a value of 1.19 is often adequate; EXAMS
defaults to this value when the entry for DFAC is outside the range
1.0-2.0.
DISO2
Dissolved Oj2 (segment, month) Units: mg/L
Concentration of dissolved oxygen in each segment of ecosystem.
DOC
Dissolved Organic Carbon (segment, month) Units: mg/L
Used for computing spectral light absorption and complexation.
DRFLD
DRiFt LoaD (segment, chemical, month) Units: ka/hour
Drift loadings: aerial drift, direct applications, stack fallout (etc.)
of chemical on each system element.
DSP
JDiSPersion coefficient (path, month) Units: m2/hour
Eddy diffusivity to be applied to dispersive exchange pairing "p". The
matching (same "p" subscript) members of JTURB, ITURB, CHARL, and XSTUR
together define a dispersive transport pathway. In the case of
horizontal mixing, DSP is the longitudinal dispersion coefficient; for
vertical mixina it may represent exchange across the thermocline or
exchanges with bottom sediments. In the latter case DSP is a statistical
kinetic composite incorporating direct sorption to the sediment surface,
mixina of the sediments by benthos (bioturbation), stirring by demersal
fishes, etc.
See also: CHARL, ITURB, JTURB, XSTUR
EAH
Ela for Acid .Hydrolysis (form, ion, chemical) Units: kcal/mole
Arrhenius activation energy of specific-acid-catalyzed hydrolysis of
chemicals. Matrix indices match those of KAH, giving, for each chemical,
data for 3 forms (1: dissolved, 2: solids-sorbed, 3: DOC-complexed) of 7
ionic species (1: neutral; 2, 3, 4: cations; 5, 6, 7: anions). When EAH
is non-zero, the second-order rate constant is calculated from:
60
-------
1000. * EAH (form,ion,chemical)
log K = KAH(f,i,c) -
(/M/hour) 4.58 * (TCEL(segment,month) + 273.15)
EAYLD
EA YleLD (path) Units: kcal
EAYLD(p) is activation energy Ea to compute transformation product yield
as a function of environmental temperatures (TCEL) . When ElA _YieLD(p) is
zero, YIELD(p) gives the dimensionless molar product yield. A non-zero
EAYLD(p) invokes a re-evaluation in which YIELD(p) is interpreted as the
pre-exponential factor in an Arrhenius-type function, giving product
yield as a function of spatially and temporally specific temperatures
(TCEL(segment, month)):
1000 * EAYLD(path)
log Yield(p) = YIELD(p) -
4.58 * (TCEL(segment,month) + 273.15)
See also: CHPAR, NPROC, RFORM, TPROD, YIELD
EBH
Ea for Base Hydrolysis (form, ion, chemical) Units: kcal/mole
Arrhenius activation energy of specific-base catalyzed hydrolysis of
chemicals. Matrix indices match those of KBH, qiving, for each chemical,
data for 3 forms (1: dissolved, 2: solids-sorhed, 3: DOC-complexed) of 7
ionic species (1: neutral, 2, 3, 4: cations, 5, <5, 7: anions). When EBH
is non-zero, the second-order rate constant is calculated from:
1000. * EBH (form,ion,chemical)
log K = KBH(f,i,c) -
(/M/hour) 4.58 * (TCEL(segment,month) + 273.15)
FHEN
Enthalpy term for HFNry's law (chemical) Units: kcal/mole
Used to compute Henry's law constants as a function of TCEL
(environmental temperature). When EHEN is non-zero, the Henry's law
constant (H) affecting volatilization at a particular (seament, month)
is computed from TCEL:
1000 * EHEN(chemical)
log H = HFNRY(chemical) -
4.58 (TCEL(seament,month) + 273.15)
61
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EK1O2
Za ^- —2 (sinqlet oxygen) (form, ion, chemical) Units: kcal/mole
Arrhenius activation energy for singlet oxygen photo-oxygenation of
chemicals. Matrix indices match those of K1O2, giving, for each
chemical, data for 3 forms (1: dissolved, 2: solids-sorbed, 3: DOC-
complexed) of 7 ionic species (1: neutral, 2, 3, 4: cations, 5, 6, 7:
anions). When EK102 is non-zero, the second-order rate constant is
calculated as:
1000. * FK1O2 (form,ion,chemical)
log K = K1O2(f,i,c) - "•
(/M/hour) 4.58 * (TCEL(segment,month) + 273.15)
ELEV
ELEVation Units: meters above mean sea level
Ground station elevation.
ENH
Ea for Neutral Hydrolysis (form, ion, chemical) Units: kcal/mole
Arrhenius activation energy for neutral hydrolysis of chemicals. Matrix
indices match those of KNH, giving, for each chemical, data for 3 forms
(1: dissolved, 2: solids-sorbed, 3: DOC-complexed) of 7 ionic species
(1: neutral, 2, 3, 4: cations, 5, 6, 7: anions). When ENH is non-zero,
the second-order rate constant is calculated from:
1000. * ENH (form,ion,chemical)
log K = KNH(f,i,c) -
(/M/hour) 4.58 * (TCEL(segment,month) + 273.15)
EOX
Ea Oxidation (form, ion, chemical) Units: kcal/mole
Arrhenius activation energy for oxidative transformations of chemicals.
Matrix indices match those of KOX, giving, for each chemical, data for 3
forms (1: dissolved, 2: solids-sorbed, 3:DOC-complexed) of 7 ionic
species (1: neutral, 2, 3, 4: cations, 5, 6, 7: anions). When EOX is
non-zero, the second-order rate constant is calculated from:
1000. * EOX (form,ion,chemical)
log K = KOX (f, i, c ) *——
(/M/hour) 4.58 * (TCEL(segment,month) + 273.15)
EPK
Qithalpy term for pK (ion, chemical) Units: kcal/mole
When EPK is non-zero, pK is computed as a function of temperature via:
62
-------
1000. * EPK(ion,chemical)
log pK = PK(i,c) -
4.58 * (TCFL(segment,month) + 273.15)
The vector indices for EPK ("c" the chemical) are:
EPK(1, c) contains datum for generation of SH+ from SH.,
FPK( 2,c) contains datum for generation of SH;?+ from SH+
EPK(3,c) " " " " " Sp3+ " SH2+
EPK(4,c) " " " " " SH~ " SH3
EPK(5,c) " " " " " SH2- " SH-
EPK(6,c) " " " " " S3~ " SH2~
ERED
jEa REDuction (form, ion, chemical) Units: kcal/mole
Arrhenius activation energy for reductive transformations of chemicals.
Matrix indices match those of KRED, giving, for each chemical, data for
3 forms (1: dissolved, 2: solids-sorbed, 3: DOC-complexed) of 7 ionic
species (1: neutral, 2, 3, 4: cations, 5, 6, 7: anions). When ERED is
non-zero, the second-order rate constant is calculated as:
1000. * FRED (form,ion,chemical)
log K = KRED(f,i,c)
(/M/hour) 4.58 * (TCEL(segment,month) + 273.15)
ESOL
Enthalpy term for SOLubility (ion, chemical) Units: kcal/mole
ESOL describes chemical solubility as a function of temperature (TCEL).
The matrix indices ("c" the chemical) denote:
ESOL(1,c) — datum for solubility of SH3 (neutral molecule)
ESOL(2,c) — " " " » SH+ (1+ cation)
ESOL(3,c) ~ " " " " SH|- (2+ cation)
ESOL(4,c) — " " » •• SH3+ (3+ cation)
ESOL(5,c) — " " » » SH- (1- anion)
63
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ESOL(6,c) — " " " " SH2- (2- anion)
ESOL(7,c) -- " " " " S3~ (3- anion)
EVAP
EVAPoration (segment, month) Units: mm/month
(Monthly) evaporative water losses from ecosystem segments.
EVPR
Molar hEat of VaPoRization (chemical) Units: kcal/mole
Enthalpy term for computing vapor pressure as a function of TCEL
(environmental temperature (segment,month)). When EVPR is non-zero,
vapor pressure Va is computed from:
1000 * EVPR(chemical)
log Va = VAPR(chemical) -
4.58 (TCEL(segment,month) + 273.15)
FIXFIL
FIXFIL signals the existence of output data for LISTs and PLOTs.
To access results from a prior run, "SET FIXFIL to 1." FIXFIL is set to
zero when EXAMS is invoked, so that the LIST and PLOT commands are
protected from attempts to access nor-existent output data files. When
results exist from a previous simulation, you can reset FIXFIL to 1 in
order to gain access to them.
FROG
F_Raction Organic Carbon (segment, month) Units: dimensionless
Organic carbon content of solids as fraction of dry weight. FROC is
coupled to KOC to generate the sediment partition coefficient for
neutral chemicals (SH3) as a function of a property (organic carbon
content) of the sediment.
HENRY
HENRY's law constant (chemical) Units: atmosphere-m-^/mole
Used in computation of air/water exchange rates (volatilization). If
parameter EHFN is non-zero, HENRY is used as the pre-exponential factor
in computing the Henrv's law constant J3 as a function of environmental
temperatures (TCEL):
1000 * EHEN(chemical)
log H = HENRY(chemical) -
4.58 (TCEL(segment,month) + 273.15)
64
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1C HEM
IDAY
IMON
I CHEMical (event)
Units: n/a
Range: 1 — KCHEM
Event "e" is a pulse of chemical number ICHEM(e) in the active database
ICHEM identifies the location in the Activity Database (ADB) of the
chemical entering the ecosystem via pulse load event "e". When, for
example, chemical data are loaded into ADB sector 3 (whether RECALLed
from the User Database Library (UDL) (via, for example, the command
sequence "RECALL CHEM 7 AS 3") or entered as new data), ICHEM(e) can be
SET to 3 to create a pulse load event of that chemical.
See also: IDAY, IMASS, IMON, ISEG.
I DAY (event)
Units: n/a
Range: 1 — 31
Pulse load event "e" takes place on day IDAY(e) of month IMON(e). The
pulse load data are organized by vertical event columns, that is, the
set of pulse load variables (IMASS(e), ICHEM(e), ISEG(e), IMON(e), and
IDAY(e)) with the same vector subscript describes a single chemical
pulse event. Thus a pulse of chemical ICHEM(e), of magnitude IMASS(e),
is released into segment ISEG(e) on day IDAY(e) of month IMON(e).
During mode 2 simulations, IDAY and IMON are inoperative.
See also: ICHEM, IMASS, IMON, ISEG.
IMASS
Initial MASS (event)
Units: kg
IMASS gives the magnitude of chemica] pulse load event "e". In mode 2,
pulses are entered at time 0 (i.e., as initial conditions), and at the
outset of each CONTINUation of the simulation. In mode 3, IMON and IDAY
specify the date of the load events. An event recurs in each year of
the RUN or CONTINUed simulation. The pulse load data are organized by
vertical event columns, that is, the series of pulse load variables
(IMASS, ICHEM, ISEG, IMON, and IDAY) with the same vector subscript
describes a single event.
See also: ICHEM, IDAY, IMON, ISEG.
I MONth (event)
Units: n/a
Range: 1—12
Pulse load event "e" takes place on day IDAY(e) of month IMON(e). The
pulse load data are organized by vertical event columns, that is, the
set of pulse load variables (IMASS(e), ICHEM(e), ISEG(e), IMON(e), and
IDAY(e)) with the same vector subscript describes a single chemical
pulse event. Thus a pulse of chemical ICHEM(e), of magnitude IMASS(e),
65
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is released into segment ISEG(e) on day IDAY(e) of month IMON(e) .
During mode 2 simulations, IDAY and IMON are inoperative.
See also: IDAY, ICHEM, IMASS, ISEG.
ISEG
I SEGment (event) Units: n/a Range: 1—KOUNT
Pulse load event "e" loads chemical ICHEM(e) on segment ISEG(e). Any
segment can receive a pulse load. Should the pulse loads increase the
FREE concentration of unionized chemical above 10-5 M (or half its
aqueous solubility, whichever is less), the size of the event is
reduced, to avoid violating the linearizing assumptions used to create
EXAMS. The pulse load data are organized by vertical event columns,
that is, the pulse load variables having the same vector subscript
define a single chemical pulse event.
See also: ICHEM, IDAY, IMASS, IMON.
I TOAD
_I TO _ADvection (path) Units: n/a Range: 0-—KOUNT (0 = export)
Chemicals are advected to seament ITOAD(p) from segment JFRAD(p). The
matching (same subscript) members of JFRAD, ITOAD, and ADVPR define an
advective hydrologic flow pathway carrying entrained chemicals and
solids through the waterbody. When ITOAD(p) is 0, the pathway advects
water and entrained substances across system boundaries, i.e., ITOAD(p)
= 0 specifies an export pathway. The flow data can be inspected by
typing "SHOW ADV"; path numbers are given above each active dataset.
Enter data with SET or CHANGE commands.
See also: JFRAD, ADVPR
ITURB
I TURbulent dispersion (path) Units: n/a Range: 0—KOUNT
Segments ITURB(p) and JTURB(p) exchange via turbulent dispersion. The
matching (same "p" subscript) members of ITURB, JTURB, CHARL, DSP, and
XSTUR together define a dispersive transport pathway; ITURB(p) and
JTURB(p) indicate which segments are linked by dispersive transport
pathway "p". A "0" in ITURB paired with a non-zero segment number in
JTURB denotes a boundary condition with a pure (zero chemical) water-
body. The input data can be examined via SHOW TURBULENCE; pathway
numbers are shown with each dataset.
See also: CHARL, DSP, JTURB, XSTUR.
IUNIT
IUNIT controls the printing of diagnostics from the integrators.
66
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Normally zero (off), it may be turned on when problems occur. To
manually set IUNIT to generate integrator diagnostic messages, SET IUNIT
TO 1. The message generator can be disabled at any time by SETting IUNIT
to 0.
JFRAD
J FRom ADvection (path) Units: n/a Range: 1—KOUNT
Chemicals are advected from segment JFRAD(p) to segment ITOAD(p). The
matching (same subscript) members of JFRAD, ITOAD, and ADVPR define an
advective hydrologic flow pathway. EXAMS computes the total net flow
available for advection from seament JFRAD(p). Of the total flow, the
fraction ADVPR(p) flows from segment JFRAD(p) into segment ITOAD(p).
The hydrologic flow carries an entrained mass of chemical along the
pathway. The flow specifications can be inspected by typing SHOW ADV;
pathway numbers are given above each active dataset. Enter data with
SET or CHANGE commands.
See also: ITOAD, ADVPR
JTURB
J TURBulent dispersion (path) Units: n/a Range: 0—KOUNT
Segments JTURB(p) and ITURB(p) exchange via turbulent dispersion. The
matching (same "p" subscript) members of JTURB, ITURB', CHARL, DSP, and
XSTUR together define a dispersive transport pathway; JTURB(p) and
ITURB(p) indicate which segments are linked by dispersive transport
pathway "p". A "0" in JTURB paired with a non-zero segment number in
ITURB denotes a boundary condition with a pure (zero chemical) water-
body. The input data can be examined via SHOW TURBULENCF; pathway
numbers are shown with each dataset.
See also: CHARL, DSP, ITURB, XSTUR
KAH
jCAcid jlydrolysis (form, ion, chemical) Units: per mole [H+]/hour
Second-order rate constant for specific-acid-catalyzed hydrolysis of
chemicals. When the matching (same subscripts) Arrhenius activation
energy (EAH) is zero, KAH is interpreted as the second-order rate
constant. When the matching entry in EAH is non-zero, KAH is
interpreted as the (Briggsian) logarithm of the freguency factor in an
Arrhenius equation, and the 2nd-order rate constant is computed as a
function of segment temperatures TCEL. Matrix indices refer to 3 forms
— 1: aqueous, 2: solids-sorbed, and 3: DOC-complexed; by 7 ions— 1:
neutral, 2-4: cations, and 5-7: anions.
KBACS
KBACteria benthoS^ (form, ion, chemical) Units: /(cfu/mL)/hr
67
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Second-order rate constants — benthic sediment bacterial biolysis of
chemicals. When the matching (same subscripts) p-10 (QTBAS) is zero,
KBACS is interpreted as the second-order rate constant. When the
matchinq entry in pTBAS is non-zero,KBACS is interpreted as the
numerical value of the second-order rate constant at 20° C, and local
values of the rate constant are computed as a function of temperature
(TCEL) in each ecosystem segment. Indices refer to 4 forms -- 1:
aqueous, 2: solids-sorbed, 3: DOC-complexed, and 4:bio-sorhed; by 7
ions— 1: neutral, 2-4: cations, and 5-7: anions.
KBACW
KBACterioplankton Water (form, ion, chemical) Units: /(cfu/mL)/hr
Second-order rate constants _K for water column bacterial biolysis of
chemicals. When the matching (same subscripts) 0-10 (OTBAW) is zero,
KBACW is interpreted as the second-order rate constant. When the
matching entry in OTBAW is non-zero,KBACW is interpreted as the
numerical value of the second-order rate constant at 20° C, and local
values of the rate constant are computed as a function of temperature
(TCEL) in each ecosystem segment. Indices refer to 4 forms -- 1:
aqueous, 2: solids-sorbed, 3: DOC-complexed, and 4:bio-sorbed; by 7
ions-- 1: neutral, 2-4: cations, and 5-7: anions.
KBH
jCBase flydrolysis (form, ion, chemical) Units: per mole [OH~]/hour
Second-order rate constant for specific-base-cata2.yzed hydrolysis of
chemicals. When the matching (same subscripts) Arrhenius activation
energy (EBH) is zero, KBH is interpreted as the second-order rate
constant. When the matching entry in EBH is non-zero, KBH is
interpreted as the (Briggsian) logarithm of the frequency factor in an
Arrhenius equation, and the 2nd-order rate constant is computed as a
function of segment temperatures TCEL. Matrix indices refer to 3 forms
-- 1: aqueous, 2: solids-sorbed, and 3: DOC-complexed; by 7 ions — 1:
neutral, 2-4: cations, and 5-7: anions.
KCHEM
Number of chemicals under review in current study. Units: n/a
KDP
^Direct Photolysis (ion, chemical) Units: reciprocal hours
Estimated photolysis rates—use only when ABSOR is unavailable. KDP is
an annual average for cloudless conditions at RFLAT, where
KDP(1,c) refer to photolysis of neutral molecules SH3
KDP(2,c) " " " " singly charged cations SH^
68
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KDP(3, c) " " " " doubly charged cations SHg+
KDP(4,c) " " " " triply charged cations SH3+
KDP(5,c) " " " " singly charged anions SH~
KDP(6,c) " " " " doubly charged anions SH2~
KDP(7,c) " " " " triply charged anions S3~
KIEC
Kp for ^pn Exchange Capacity (ion, chemical) Units: Kp /(meq/100g dry)
Coefficient relating Kp of ions to exchange capacity of sediments. KIEC
times CECjseg, month) (or AEC) gives Kp for sorption of ions with solid
phases. Overridden by explicit (non-zero) values of KPS.
KIEC(1,c) contains datum for relating sorption of SH+ to C.E.C.
KIEC(2,c) " " " " " " SH2+
KIEC(3,c) " " " " " " SH3+
KIEC(4,c) " " " " " " SH~ to A.E.G.
KIEC(5,c) " " " " " " SH2_
KIEC(6,c) " " " " " " S3_
KINOUT
Logical Unit Number for writing results of numerical integration to
kinetics plotting file.
KNH
KNeutral ^lydrolysis (form, ion, chemical) Units: per hour
Pseudo-first-order rate constants for neutral hydrolysis of chemicals.
When the matching (same subscripts) Arrhenius activation energy (ENH) is
zero, KNH is interpreted as the second-order rate constant. When the
matching entry in ENH is non-zero, KNH is interpreted as the (Briggsian)
logarithm of the frequency factor in an Arrhenius equation, and the 2nd-
order rate constant is computed as a function of segment temperatures
TCEL. Matrix indices refer to 3 forms -- 1: aqueous, 2: solids-sorbed,
and 3: DOC-complexed; by 7 ions — 1: neutral, 2-4: cations, and 5-7:
anions.
69
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KOC
Koc(chemical) Units: ((mg/kg)/(mg/L)) / (organic carbon fraction)
KOC is partition coefficient (Kp) keyed to organic carbon content
FROG(s, m) of the sediment solids in each (s) segment, during each (m)
month of simulation of chemical behavior in the system. Multiplication
of KOC by the organic carbon fraction FROG(s) of the solids in each
segment yields the partition coefficient (Kp) for sorption of unionized
(SH3) species with those solids:
Kp(chemical, segment, month) = KOC(chemical) * FROC(segment, month)
KOUNT
Number of segments used to define current ecosystem. Units: n/a
KOW
C)ctanol-Water partition coefficent (chemical) Units: (mg/L)/(mg/L)
Kow is an experimentally determined chemical descriptor. Kow (KOW(c))
can be used to estimate Koc (c.f.), and thus relate the Kp of a chemical
to the organic carbon content of sediments.
KOX
K. (DXidation (form, ion, chemical) Units: per mole [OXRAD] /hour
Second-order rate constants for free-radical (OXRAD) oxidation of
chemicals. When the matching (same subscripts) Arrhenius activation
enercry (BOX) is zero, KOX is interpreted as the second-order rate
constant. When the matching entry in EOX is non-zero, KOX is
interpreted as the (Briggsian) logarithm of the frequency factor in an
Arrhenius equation, and the 2nd-order rate constant is computed as a
function of segment temperatures TCEL. Matrix indices refer to 3 forms
— 1: aqueous, 2: solids-sorbed, and 3: DOC-complexed; by 7 ions — 1:
neutral, 2-4: cations, and 5-7: anions.
KO2
KO2(segment, month) Units: cm/hour
Oxygen exchange constant or piston velocity at 20° C in each ecosystem
segment.
KPB
KP for jBiomass (ion, chemical) Units: (ug/g) / (mg/L)
Partition coefficient (Kp) for computing equilibrium biosorption. The
"ion" subscripts ("c" is the chemical) identify:
KPB(1,c) -- datum for biosorption of SH^ (neutral molecule)
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KPB(2,c) — datum for biosorption of
KPB(3,c) —
KPB(4,c) —
KPB(5,c) —
KPB(6,c) —
KPB(7,c) —
II 11
II II
It II
II II
of
II
II
n
11
n
SH4
SH5+
SHg
SH-
SH2-
S3-
(1 +
(2+
(3+
(1-
(2-
(3-
cation
cation
cation
anion)
anion)
anion )
KPDOC
KPDissolved Organic Carbon (ion, chemical)
Units: (ug/g)/(mg/L)
Partition coefficient (Kp) for equilibrium complexation with DOC. The
"ion" subscripts ("c" is the chemical) identify:
KPDOC(1,c) -- datum for complexation of SH3 (neutral molecule)
KPDOC(2,c) — datum for complexation of SH^ (1+ cation)
KPDOC(3,c) --
KPDOC(4,c) --
KPDOC(5,c) —
KPDOC(6,c) —
KPDOC(7,c) —
11 SH2+ (2+ cation)
" SH|+ (3+ cation)
" SH- (1- anion)
" SH2~ (2- anion)
" S3~ (3- anion)
KPS
KP for Sediment solids (ion, chemical)
Units: (mg/kg)/(mg/L)
Partition coefficients (Kp) for computing sorption with sediments. The
"ion" subscripts ("c" is the chemical) identify:
KPS(1,c) -- datum for sorption of SH3 (neutral molecule)
KPS(2,c) — datum for sorption of SH^ (1+ cation)
KPS(3,c) —
KPS(4,c) —
KPS(5,c) —
KPS(6,c) —
KPS(7,c) —
i+ (2+ cation)
SH
SH|+ (3+ cation)
SH~ (1- anion)
SH2- (2- anion)
S3- (3- anion)
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KRED
KREDuction (form, ion, chemical) Units: per mole [REDAG] /hour
Second-order rate constants for REDucinq AGent chemical reduction of
compounds. When the matching (same subscripts) Arrhenius activation
energy (BRED) is zero, KRED is interpreted as the second-order rate
constant. When the matching entry in BRED is non-zero, KRED is
interpreted as the (Briggsian) logarithm of the frequency factor in an
Arrhenius equation, and the 2nd-order rate constant is computed as a
function of segment temperatures TCEL. Matrix indices refer to 3 forms
-- 1: aqueous, 2: solids-sorbed, and 3: DOC-complexed; by 7 ions
neutral, 2-4: cations, and 5-7: anions.
KVO
KVOlatilization (chemical) Units: dimensionless ratio
Liquid-phase transport resistance, as ratio to reaeration rate.
K102
K1O2(singlet oxygen) (form, ion, chemical) Units: per M [1O2] /hr
Second-order rate constants for singlet oxygen photo-oxygenation of
chemicals. When the matching (same subscripts) Arrhenius activation
energy (EK1O2) is zero, K1O2 is interpreted as the second-order rate
constant. When the matching entry in EK1O2 is non-zero, K1O2 is
interpreted as the (Briggsian) logarithm of the frequency factor in an
Arrhenius equation, and the 2nd-order rate constant is computed as a
function of segment temperatures TCEL. Matrix indices refer to 3 forms
-- 1: aqueous, 2: solids-sorbed, and 3: DOC-complexed; by 7 ions -- 1:
neutral, 2-4: cations, and 5-7: anions.
LAMAX
LAMbda MAXimum (ion, chemical) Units: nanometers
Wavelength of maximum absorption of light by each ionic species, or
wavelength of maximum overlap of solar spectrum and chemical's
absorption spectrum (of each ion). Indices match with KDP matrix. LAMAX
selects the wavelengths used to compute light extinction factors for
photochemical transformation, in those cases where the absorption
spectrum of the compound is not available, but the results of simple
photochemical experiments can be used as a coarse estimate of rates of
photochemical transformations (i.e., KDP > 0.0). When set to zero,
LAMAX defaults to 300 nm.
LAT
LATitude Units: degrees and tenths (e.g., 37.24)
Geographic latitude of the ecosystem.
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LENG
LENGth (segment) Units: m
Length of a reach — used to compute volume, area, depth.
LOADNM
LOADings database NaMe (50 characters) Units: n/a
Do NOT use "CHANGE" or "SET" to enter names! The NaMe for a LOADings
database is entered via the command sequence:
EXAMS > LOAD NAME IS nnn...
where "nnn... " can include as many as 50 characters. This name is
associated with chemical loadings database library entries, so that load
patterns can be found in the catalog. The Ith character can be
corrected with a CHANGE or SFT command. For example, to repair the 7th
character, "SFT LOADNM(7) TO ... ."
LONG
LONGitude Units: degrees and tenths (e.g., 154.2)
Geographic longitude of the ecosystem.
MCHEM
M CHEMical Units: n/a
Number of chemical in activity data base.
MODE
MODE sets the operating "mode" of EXAMS.
Three operating modes are available; these are selected by SETting MODE
to 1, 2, or 3.
MODE Operational characteristics of EXAMS
1 Long-term (steady-state) analysis.
2 Pulse analysis — specifiable initial chemical mass
(IMASS) and time frame, time-invariant environment.
3 Monthly environmental data, daily pulse loads IMASS
and monthly chemical loadings of other types.
MONTH
MONTH Units: n/a
Set MONTH to inspect a specific block of environmental data.
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MWT
Gram Molecular WeighT (chemical) Units: g/mole
Molecular weight of the neutral species of each study chemical. Changes
in molecular weight due to ionization are neglected.
NPROC
Number of PROCess (path) Units: n/a Range: 1--9
Signals the type of process transforming CHPAR(p) into TPROD(p).
NPROC can be set to the following:
1 —> specific acid hydrolysis
2 --> neutral hydrolysis
3 —> specific base hydrolysis
4 —> direct photolysis
5 —> singlet oxygen reactions
6 —> free radical oxidation
7 —> water column bacterial biolysis
8 —> benthic sediment bacterial biolysis
9 —> reductions, e.g., reductive dechlorination
See also: CHPAR, EAYLD, RFORM, TPROD, YIELD
NPSED
_Npn-Ppint-Source SEDiment (segment, month) Units: kg/hour
Non-point-source sediment loads entering ecosystem segments.
NPSFL
Non-Ppint-Source FLow (segment, month) Units: m3/hour
Non-point-source water flow entering ecosystem segments.
NPSLD
Non-Ppint-Spurce Lpal) (segment, chemical, month) Units: kg/hour
Chemical loadings entering segments via non-point sources.
NYEAR
Number of YEARs Units: n/a
NYEAR is number of years to be simulated for a mode 3 run.
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OXRAD
OXidant RADicals (month)
Units: moles/L
Concentration of environmental oxidants in near-surface waters (e.g.,
peroxy radicals). EXAMS computes segment-specific oxidant
concentrations using ultra-violet light extinction in the system.
OZONE
OZONE (month) Units: centimeters NTP Typically 0.2 — 0.3 cm
Mean (monthly) ozone (O^) content of atmosphere.
PCPLD
PH
^reCiPitation Lpal) (segment, chemical, month)
Chemical loadings entering each segment via rainfall.
Units: kg/hour
PC TWA
PerCenT WAter (segment, month)
Units: dimensionless
Percent water in bottom sediments of benthic segments. Elements of
these vectors that correspond to water column segments are not used
(dummy values). PCTWA should be expressed as the conventional soil-
science variable (the fresh weight : dry weight ratio times 100); all
values must be greater than or equal to 100. An entry in PCTWA that is
less than 100.0 for a benthic segment raises an error condition, and
control is returned to the user for correction of the input data.
pH (segment, month)
Units: pH units
The negative value of the power to which 10 is raised in order to obtain
the temporally averaged concentration of hydronium ions [H3O+] in gram-
equivalents per liter.
PK
pK (ion, chemical)
Negative of base-10 logarithm of acid/base dissociation constants. When
the matching value in the EPK matrix is zero, J^K(i, c) is taken as the
pK value. (To "match" is to have the same subscript values.) When
EPK(i, c) is non-zero, PK is taken as the base-10 logarithm of the pre-
exponential factor in the equation for pK as a function of environmental
temperature TCEL, that is,
1000 EPK(ion,chemical)
log pK = PK(i,c) -
4.58 (TCEL(segment,month) + 273.15)
75
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The vector indices for PK ("c" the chemical) are:
P_K(1,c) contains datum for generation of SH+ from SH3
PK(2,c) " " " " " SH2+ from SH+
•nv t "3 r*, \ " " " " " CH-^"^~ " QM^"'"
¥&\ J5, C ) 6 5
PK(4,c) " " " " " SH- " SH3
PK(5,c) " " " " " SH2- " SH-
PK(6,c) " " " " " S3~ " SH2~
PLMAS
PLanktonic bioMASs (segment, month) Units: mg (dry weight)/L
Total plankton subject to hiosorption of xenobiotic chemicals.
POH
pOH (segment, month) Units: pOIJ units
The negative value of the power to which 10 is raised in order to obtain
the temporally averaged concentration of hydroxide [OH-] ions in gram-
equivalents per liter.
PRINTR
Logical Unit Number used for printing results on a line printer.
PRODNM
PRODuct chemistry database NaMe (50 characters) Units: n/a
Do NOT use "CHANGE" or "SET" to enter names! The NaMe for a PRODuct
chemistry database is entered via the command sequence:
EXAMS > PRODUCT NAME IS nnn.. .
where "nnn... " can include as many as 50 characters. This name is
associated with product chemistry database library entries, so that
databases can be found in the catalog. Use a CHANGE or SET command to
repair single characters in the name. For example, to repair character
seven, enter "SET PRODNM(7) TO ... ."
PRSW
PRint Switch Units: n/a
PRSW is a switch for controllina printing options. In mode 3, when PRSW
is set to 0 (the default), average values of the environmental
76
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parameters are recorded in the run log. When PRSW is 1, a separate
tahle is produced for each (monthly) data set, except for those values
which'are invariant (VOL etc.).
QTBAS
Q Ten BActeria benthoS (form, ion, chemical)
Units: dimensionless
Q-10 values for benthic bacterial biolysis (see KPACS) of chemical, "Q-
10" is the increase in the second-order rate constant due to a 10° C
increase in temperature. Indices refer to 28 molecular spp: 4 forms —
1: aqueous, 2: solids-sorbed, 3: DOC-complexed, and 4: bio-sorbed; by 7
ions -- 1: neutral, 2-4: cations, and 5-7: anions. When QTBAS is non-
zero, the matching (same subscripts) rate constant is computed as:
(TCEL(seg,month)-20)/10
Kbacs(f,i,c) = QTBAS(f,i,c)
* KBACS(f,i,c)
QTBAW
Q Ten BActeria Water (form, ion, chemical)
Units: dimensionless
Q-10 values for bacterioplankton biolysis (see KBACW) of chemical. "p-
10" is the increase in the second-order rate constant due to a 10° C
increase in temperature. Indices refer to 28 molecular spp: 4 forms —
1: aqueous, 2: solids-sorbed, 3: DOC-complexed, and 4: bio-sorbed; by 7
ions — 1: neutral, 2-4: cations, and 5-7: anions. When QTBAW is non-
zero, the matchincr (same subscripts) rate constant is computed as:
(TCEL(seg,month)-20)/10
Kbacw(f,i,c) = QTBAW(f,i,c)
* KBACW(f,i,c)
QUANT
RAIN
QUANTum yield (form, ion, chemical)
Units: dimensionless
Reaction quantum yield for direct photolysis of chemicals -- fraction of
the total light guanta absorbed by a chemical that results in
transformations. Separate values (21) for each potential molecular type
of each chemical allow the effects of speciation and sorption on
reactivity to he specified in detail. The matrix of 21 values specifies
guantum yields for the (3) physical forms: (1) dissolved, (2) sediment-
sorbed, and (3) DOC-complexed; of each of (7) possible chemical species:
neutral molecules (1), cations (2-4), and anions (5-7). (QUANT is an
efficiency.)
RAINfall (month)
Average (monthly) rainfall in geographic area of system.
Units: mm/month
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RANUNT
Logical Unit Number for the UTILITY file support.
The UTILITY file is used for retrieving and storing chemical and
environmental parameters, for supporting the on-line assistance
facility, and to support the SYSTEM PARAMETERS operations.
REDAG
REDucing AGents (segment, month) Units: moles/L
Molar concentration of reducing agents in each system segment.
RELER
RELative ERror tolerance for integrators.
When the characteristics of the chemical and ecosystem are such as to
result in "stiff" equations, numerical errors may lead to small negative
numbers in the time series. If desired, the value of ABSER and RELER
can be decreased in order to achieve greater precision in the simulation
outputs.
RFLAT
ReFerence LATitude (ion, chemical)
Units: degrees (e.g., 40.72)
( RFLAT - LAT) corrects for N/S displacement of the ecosystem LAT from
the location (RFLAT) of a matched (same subscript) KDP.
RFLAT ( 1 , c ) refer to photolysis of neutral molecules
SH
RFLAT ( 2, c)
RFLAT(3,c)
RFLAT(4,c)
" "
" "
RFLAT(5,c)
RFLAT(6,c) "
" "
RFLAT(7,c)
" "
" singly charged cations SH+
" doubly charged cations SH^
" triply charged cations SH|+
" singly charged anions SH~
" doubly charged anions SH2-
" triply charaed anions S3~
RFORM
Reactive FORM (path)
Units: n/a Range: 1--32
RFORM gives the reactive molecular form (ionic species in each of the
possible sorptive states) of CHPAR(p) resulting in product TPROD(p).
The table shows the value of RFORM for each molecular entity^ Including
values for total dissolved (29), solids-sorbed (30), etc.
78
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Ionic spp. Neutral Cations Anions Total
& valence : (0) (1+) (2+) (3+) (1-) (2-) (3-) (all)
Forms:
Dissolved 1 5 9 13 17 21 25 29
Solids-sorhed 2 6 10 14 18 22 26 30
DOC-complexed 3 7 11 15 19 23 27 31
Biosorbed 4 8 12 16 20 24 28 32
See also: CHPAR, EAYLD, NPROC, TPROD, YIELD
RHUM
Relative HUMidity (month) Units: %, i.e., saturation = 100% R.H.
Mean (monthly) relative humidity during daylight hours. Data typical of
daylight hours are needed because their primary use is to characterize
light transmission in the atmosphere.
RPTOUT
Logical Unit Number for data written to tabular report file.
SEELD
SEEpage LoaD (segment, chemical, month) Units: kg/hour
Chemical loadings entering the system via "interflows" or seepage (all
sub-surface water flows entering the system, (usually) via a benthic
segment).
SEEPS
SEEPage flowS (segment, month) Units: m^/hour
Interflow (subsurface water flow, seepage) entering each segment. SEEPS
usually enter via a benthic segment. SEEPS are assumed to lack an
entrained sediment flow, that is, they are flows of water only.
SOL
SOLubility (ion, chemical) Units: mg/L
Agueous solubility of each species (neutral molecule + all ions). When
the matching value in the ESOL matrix is zero, SOL(i, c) is taken as the
aqueous solubility in mg/L. (To "match" is to have the same subscript
values.) When ESOL(i, c) is non-zero, SOL(i, c) is taken as the base-10
logarithm of the pre-exponential factor of the equation describing the
MOLAR solubility of the species as a function of environmental
temperature (TCEL). The vector indices for SOL are given in the text
describing ESOL. Solubility must be specified, because it is used as a
constraint on loads.
79
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SPARE2
SPFLG
SPeci&s FLa£s (ion, chemical) — can be "1" (exists) or "0".
This vector of "flaas" or "switches" shows which ions exist. Set the
flags ("SET SPFLG(i, c) TO 1") when entering chemical data in order to
show EXAMS the ionic structure of the chemical.
SPFLG(1) set (=1) signals that the neutral molecule SH^ exists.
SPFLG(2) set signals existence of singly charged cation SHt
SPFLGQ) " " " " doubly " " SFJ?+
SPFLG(4) " " " " triply " " SH|+
SPFLG(5) " " " " singly " anion SH2~
SPFLG(6) " " " " doubly " " SH2~
SPFLG(7) " " " " triply " " S3~
SSOUT
Logical Unit Number for data written to plotting file containing EXAMS'
steady-state chemical concentrations.
STFLO
^Tream FLOws (segment, month) Units: m^/hour
Flow into head reach of river or estuary; segment tributaries and creeks
or other streamflows entering a lake or pond. Note that STFLO
represents stream flow entering system segments from external sources
ONLY. EXAMS itself computes hydrologic flows among segments that are
part of the waterbody being studied, via the specified advective and
dispersive flow patterns (see JFRAD, JTURB, etc.) Therefore, do NOT
compute net water balances for each segment and enter these into the
database—enter ONLY those flows entering the system across external
boundaries!
STRLD
STReam LpaI3 (segment, chemical, month) Units: kg/hour
Chemical loadings entering ecosystem segments via stream flow.
STSED
£>Tream-borne SEDiment (segment, month) Units: kg/hour
Stream-borne sediment load entering ecosystem segments.
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SUSED
Suspended SEDiment (segment, month) Units: mg/L.
Suspended particulate matter — applicable to the water column only.
SYSTYP
Name of aquatic ecoSYStem TYPe (50 characters) Units: n/a
Do NOT use "CHANGE" or "SET" to enter names! The name of a waterbody is
entered into the database via the command sequence:
EXAMS > ENVIRONMENT NAME IS nnn...
where "nnn... " can include as many as 50 characters. This name is
associated with environmental library entries (the UDB catalog) and is
printed in the header information of the appropriate output tables. Use
SET and CHANGE to correct single characters in the name. For example,
to correct the seventh character in a name, "CHAN SYSTYP(7) TO ... ."
TCEL
Temperature CELcius (segment, month) Units: degrees C
Average temperature of ecosystem segments. Used (as enabled by input
data) to compute effects of temperature on transformation rates and
other properties of chemicals.
TCODE
The value of Time CODE sets the units of TINIT, TEND, and CINT.
TCODE can be SET to 1 (hours), 2 (days), 3 (months), or 4 (years).
TCODE is under full user control only in Mode 2. In mode 2, TCODE
controls the time frame of the study. For example, given TINIT^O.,
TEND=24., and CINT=2.; CHANging TCODE from 1 to 3 converts a 0-24 hour
study into 0-24 months, with bimonthly reports. In mode 1, EXAMS
selects the units for reporting results, from the probable half-life of
the study chemical(s). In mode 3, a RUN encompasses one year or longer,
and the timing is set to produce standard outputs.
TEND
TTime END for a dynamic simulation seament. Units: see TCODE
A simulation segment encompasses the period TINIT through TEND. At the
end of each integration, TINIT is reset to TEND. The simulation can be
extended by invoking the "CONTINUE" command; EXAMS will then request a
new value of TEND. Pulse loads (IMASS) and longer-term chemical loads
(STRLD, NPSLD, etc.) can be modified or deleted during the pause between
simulation segments.
-------
TINIT
T?ime INITial for a dynamic simulation segment. Units: see TCODE
A'simulation RUN encompasses the period TINIT through TEND. At the end
of each integration, TEND is transferred to TINIT. The simulation
results can be evaluated, and the study continued via the "CONTINUE"
command. EXAMS will note the new value of TINIT and request a new
endpoint. Pulse and other chemical loadings can be modified or deleted
between simulation segments.
TPROD
Transformation PRODuct (path) Units:n/a Range: 1-KCHEM
TPROD(p) — ADB location of the transformation product of CHPAR(p). The
matching (same transformation path number "p") members of CHPAR and
TPROD give the location numbers in the active database of the parent
chemical and the transformation product for pathway "p". For example,
SET CHPAR(p) TO 1, and TPROD(p) to 4, to show that the chemical in ADB
sector 4 is produced via transformation of the chemical in ADB sector 1,
via process data defined by the remaining members of product chemistry
sector "p".
See also: CHPAR, EAYLD, NPROC, RFORM, YIELD
TTYIN
Logical Unit Number for interactive input commands.
TTYOUT
Logical Unit Number for output error messages and warnings, and for
EXAMS' interactive responses.
TYPE
Segment TYPE (segment) Units: letter codes
Letter codes designating segment types used to define ecosystems.
Available types: Littoral, Epilimnion, Hypolimnion, and Benthic.
UDB
User DataBase
Long-term retention of data required by EXAMS is provided by storage
in the "User Database" (UDB, generally resident on a physical device,
e.g., a hard disk) for CHEMICALS, ENVIRONMENTS, LOADs, or PRODUCTS.
Within each of these UDB sectors, each dataset is CATALOGed via a unique
accession number (UDB#). When transferring data between foreground memory
(the activity database or ADB) and a UDB, the target location must be
specified by the name of the UDB sector and the accession number within
82
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the sector. For example, to STORE the current pattern of chemical
loadings: STORE LOAD 7. Similarly/ to retrieve or RECALL data from a
UDB into the ADB for use in an analysis, one could enter: RECALL LOAD 7.
VAPR
VAPoR pressure (chemical) Units: Torr
Used to compute Henry's law constant when HENRY datum is zero (0) but
VAPR is non-zero:
VAPR / 760.
HENRY =
SOL / MWT
If the associated molar heat of vaporization (EVPR) is non-zero, VAPR is
taken as the base-10 logarithm of the pre^exponential factor in an
exponential function describing vapor pressure as a function of
temperature (TCEL).
VOL
VOLume (segment) Units: m^
Total environmental volume of ecosystem segments.
WIDTH
WIDTH (segment) Units: m
Average bank-to-bank distance -- for computing volume, area, depth of
lotic systems described via length, width, and cross-sectional areas.
WIND
WINDspeed (segment, month) Units: m/second
Average wind velocity at a reference height of ten centimeters above the
water surface. Parameter is used to compute a piston velocity for water
vapor (Liss 1973, Deep-Sea Research 20:221) in the 2-resistance
treatment of volatilization losses.
XSA
Cross-sectional (XS) Area (segment) Units:
Area of waterbody in section along advective flowpath.
XSTUR
XSection for TURbulent dispersion (path) Units: m^
XSTUR is cross-sectional area of a dispersive exchange interface at the
boundary between segments JTURJB(p) and ITURB(p). The matching (same "p"
subscript) members of JTURB, ITURB, CHARL, DSP, and XSTUR collectively
83
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define a dispersive transport pathway. The exchange constant E^(p) is
computed as:
E_(p) (m3/hour) = DSP(p) XSTUR(p) / CHARL(p)
See also: CHARL, DSP, ITURB, JTURB
YEAR1
YEAR 1
Starting year for mode 3 simulation (e.g., 1985).
YIELD
YIELD of product (path)
Units: n/a
Units: mole/mole
YIELD(p) is the product yield from the transformation pathway "p" with
dimensions mole of transformation product TPROD(p) produced per mole of
parent compound CHPAR(p) reacted (dimensionless).
See also: CHPAR, EAYLD, NPROC, RFORM, TPROD
U.S. Environ r-•-• \ Pixtoction Agency
Region V, Lih :.y
230 South Dearborn Street ^^
Chicago, Illinois 60604 .
"U.S.Government Printing Office: 1985 — 559-111/10842
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