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RBCA
Tool Kit for Chemical Releases and RBCA
Tool Kit for TRRP
FREQUENTLY ASKED QUESTIONS
Below is a selected listing of common technical support issues
encountered by users of the RBCA Tool Kit for Chemical Releases.
We update this page frequently to help you get the most out of your
software.
INSTALLATION
AND STARTUP
1.
How do I install or reinstall the RBCA Tool Kit?
Installation:
1. Both
the RBCA Tool Kit for Chemical Releases and the RBCA Tool Kit for
TRRP come delivered as an executable ZIP file. Run the setup file
and allow the files to unzip by clicking "Unzip".
2. You
may then start the RBCA Tool Kit by running the start file (C:\rbca\RBCAstart.xla
for Chemical Releases, C:\GSI_TRRP\TRRPstart.xla for TRRP). Note:
You must enable macros in Excel in order to use the RBCA Tool Kit.
3. You
will then be prompted to enter in your registration number and user
information. Enter in the information and review your End User License
Agreement. After reviewing, you can click "I Agree" to continue.
4. You
will then be given an access code which is used to register your
software. You can either click "Get Security Code On-line" to get
the code directly from GSI's server, or you can get your security
code by:
Telephone:
713-522-6300
Web: software/SoftwareRegistration.asp
5. Once
you have the security code, you can click "OK" to begin using the
RBCA Tool Kit.
How
do I reinstall the RBCA ToolKit?
Reinstallation:
Reinstalling
may sometimes be necessary. To reinstall:
1. You
may wish first wish to copy your toxicity database (UserChemTox.xls)
to another folder, in order to preserve your user-defined settings.
2. You
can then delete all of the RBCA Tool Kit program files (there are
seven).
3. Reinstall
from the original media (CD, or zip file), if it was electronically
delivered. You can then register the software as normal.
4. Make
sure to replace the UserChemTox.xls file after you have completed
reinstalling.
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2. How do
I get a security code when the "Get Security Code On-line" button
is grayed out?
This
occurs when the user's computer is either not connected to the Internet,
or is otherwise blocked by a firewall or proxy server from connecting
to the security code server.
You may
get a security code online at: software/SoftwareRegistration.asp
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3. The RBCA
Tool Kit fails at startup. What does "Run-time error '91': Object
variable or With block variable not set" mean?
This
occurs when the RBCA Tool Kit files are corrupted, most often the
result of improperly closing the RBCA Tool Kit. The user must reinstall
the RBCA Tool Kit from original media, and should take care to always
close the RBCA Tool Kit from the "quit" button located in the lower
right hand corner of the main menu, and not by simply closing excel.
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4. Why does the RBCA Tool Kit not work after updating to Office
2000/XP?
This
is a problem with users who have upgraded to Office 2000 or Office
XP. Upon installation of the new Office, the security for the Office
applications is set to "High", disabling all unsigned macros without
prompting the user. While this protects the user against malicious
macros, it also prevents the use of the RBCA Tool Kit.
To change
the security setting in Excel, go to Tools > Macro > Security
and select the security level to "Medium". Then restart the RBCA
Tool Kit using RBCAstart.xla. It should prompt you for permission
to run the macros in the RBCA Tool Kit.
It should
be noted that, by changing the security setting, it is possible
for a user to run harmful macros, although they will be prompted
before doing so. Also, some companies have intentionally disabled
macros for security reasons. Users in this situation will need to
consult with their I.T. administrator, as the RBCA Tool Kit will
not work with the macros disabled.
It was
also noted that there are some problems running the RBCA Tool Kit
for TRRP under Office XP. This problem may be resolved by applying
Office Service Pack 2. This is freely downloadable from the Microsoft
websit at http://www.microsoft.com/downloads/details.aspx?FamilyID=1a8ce553-ab76-4a63-99da-b4ed914c1514&DisplayLang=en.
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5. Why do I get a
"Type Mismatch" Error at startup?
(
SOFTWARE PATCH AVAILABLE )
The
RBCA Tool Kit for Chemical Releases, version 1.2 and earlier may
fail to start properly (Excel reports a "Type Mismatch" macro error)
after customizing certain chemicals in the chemical data base.
The
problem stems from a few of the CAS numbers in the built-in database
containing dashes ("-") whereas they should be stored as numbers
alone. (for example, "7440-36-0" verses "7440360" for Antimony.)
When the software loads the custom database upon startup, dashes
included in a CAS number will cause a "Type Mismatch" error
in Excel.
We
cannot correct the built-in database until a future software update
is released; however, in the meantime faulty CAS numbers in the
custom chemical database can be fixed with the "patch" program. To
do this:
1.
Download the file User ChemTox patch.xls and open it
in Excel.
2.
The patch program will prompt you to select your custom database
file ("UserChemTox.xls").
3.
Check and convert any faulty CAS numbers, then save and close the
file. Please be sure to select "No" when prompts whether to
update links. (Selecting "Yes" will not hurt anything, but
could tie up your computer for awhile.)
4.
After running the patch program, you should be able to successfully
restart the RBCA Tool Kit with your customized chemical data.
To circumvent this problem while customizing your chemical database
again in the future, you can simply reenter the CAS number without
any dashes along with your customized values. If the "type
mismatch" error occurs again when reinstalling the RBCA Tool Kit,
you can run the patch program again to clean up the custom database
file.
Download Patch:
User ChemTox patch.xls
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SYSTEM
REQUIREMENTS
1. Can I run the RBCA Tool Kit in non-English versions
of Office and Windows?
Since
there have been reports of problems running the RBCA Tool Kit under
non-English language versions of Excel and Windows with success,
GSI recommends using the English language versions of both Excel
and Windows, and will not support users running in any other versions.
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2. Why does the RBCA Tool Kit not work after updating to Office
2000/XP?
This
is a problem with users who have upgraded to Office 2000 or, more
recently, Office XP. Upon installation of the new Office, the security
for the Office applications is set to "High", disabling all unsigned
macros without prompting the user. While this protects the user
against malicious macros, it also prevents the use of the RBCA Tool
Kit.
To change
the security setting in Excel, go to Tools > Macro > Security
and select the security level to "Medium". Then restart the RBCA
Tool Kit using RBCAstart.xla. It should prompt you for permission
to run the macros in the RBCA Tool Kit.
It should
be noted that, by changing the security setting, it is possible
for a user to run harmful macros, although they will be prompted
before doing so. Also, some companies have intentionally disabled
macros for security reasons. Users in this situation will need to
consult with their I.T. administrator, as the RBCA Tool Kit will
not work with the macros disabled.
It was
also noted that there are some problems running the RBCA Tool Kit
for TRRP under Office XP. This problem may be resolved by applying
Office Service Pack 2. This is freely downloadable from the Microsoft
websit at http://www.microsoft.com/downloads/details.aspx?FamilyID=1a8ce553-ab76-4a63-99da-b4ed914c1514&DisplayLang=en.
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SOFTWARE
REVISIONS AND UPDATES
1. How do I find and install updates to the RBCA Tool Kit?
GSI occasionally
releases updates to our software products. Sometimes our updates
are free, sometimes we charge, depending on the nature of the update.
The latest
versions of our software are as follows:
RBCA
Tool Kit for Chemical Releases: Version 1.3b
RBCA
Tool Kit for TRRP: Version 1.5TX
Download and order updates here
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USING
THE TOOL KIT
1. Why is Lead
Not Included in the Chemical Database?
Lead
is a non-cancer toxicant which is known to cause central nervous
system (CNS) effects in children. The U.S. Environmental Protection
Agency (USEPA) has established reference dose (RfD) values for a
large number of non-cancer toxicants. Exposure to a compound
at a level below the RfD is assumed to be safe. However, studies
of lead toxicity have not established a "safe" exposure limit for
lead. Therefore, the USEPA has not established an RfD for
lead. RfD values for lead are not provided in the USEPA IRIS
database or in any other toxicity database widely used to select
toxicity values for the RBCA process. In the RBCA process,
the RfD value is required to calculate the risk-based cleanup standard
(RBSL or SSTL) for a non-cancer toxicant. Because no widely
accepted RfD value has been established for lead, it is not possible
to include lead in the RBCA Tool Kit database. Lead can be
added to the software using the "Add New Chemical" tool. However,
the user will be required to provide an RfD value and other relevant
chemical parameters.
The
U.S. EPA has established an action level for drinking water limit
of 0.015 mg/L. In addition, the state of Texas has established
a limit of 500 mg/kg for direct exposure to residential soils, and
Louisiana has established a limit of 400 mg/kg for direct exposure
to residential soils. However, none of these limits are risk-based
limits.
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2. Why
do my Forward and Backward Calculations Yield Different Results?
When
performing a RBCA assessment, comparing the results for the backward
calculation (risk-based cleanup levels) to the results for the forward
calculation (risk levels) does not always yield the same result
for a site. In other words, comparing calculated risk levels
to user-specified target risks may indicate that risk levels are
acceptable at a site; however, concentrations detected at the site
may exceed risk-based screening levels (e.g., RBSLs) generated using
the same target risks, or vice versa. When reading the following,
please keep in mind that forward-mode calculations include the transient
Domenico analysis worksheets, and cumulative risk calculation sheet,
and backward-mode calculations include the TPH calculation worksheets.
In
general, the two modes use the same models and input parameters,
but in certain cases, the results will not always be identical because
the two modes use different assumptions. The primary reasons the
two methods may not always give the same results are listed below:
Backward-mode calculations sometimes include non-risk-based
criteria, such as MCLs, as alternate criteria to the risk-based
values.
Backward-mode
calculations screen out results that exceed solubility or soil
residual concentrations for indirect pathways. Target
values calculated above these levels are flagged by the software
as ">", and either the aqueous solubility or soil saturation
limit, depending on whether a groundwater or soil concentration
is being reported. Forward-mode calculations do not screen
for these values, which may result in inappropriately large
risk values.
Backward-mode calculations for the surface soil pathway will
combine intakes due to ingestion, dermal contact, and inhalation
of volatiles and particulates. Forward mode calculations
do not combine these intakes.
These
inconsistencies result from standard practices within the technical
community that differ between the two methods. As with any
model, the user is advised to review the underlying assumptions
and determine whether they are appropriate for conditions at the
site being modeled.
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3. How do I use the
RBCA Tool Kit to calculate performance standards for a Groundwater
Barrier Wall?
To develop performance standards for a groundwater
barrier wall, the RBCA Tool Kit can be run in "backward mode" to
determine the applicable groundwater SSTLs based on the site-specific
source location, groundwater parameters, and applicable point of
exposure. These calculated SSTL values for each COC can then
be entered into the software as the Representative Source Concentrations
and the software rerun in "forward mode" using the Transient Domenico
Worksheet to determine the predicted steady-state
plume concentrations at each point downstream of the source location.
As long as an engineered barrier serves to prevent the downstream
concentrations from exceeding these allowable levels, the risk limits
at the point of exposure will not be exceeded. In other words,
the steady-state Domenico plot shows how much the groundwater barrier
can leak before it becomes a problem. If a barrier wall is
installed, the concentration limits determined in this manner can
be used to monitor the performance of the wall.
A
similar analysis can be run for the soil leaching pathway by i)
entering the actual measured soil COC concentrations and other site-specific
soil and groundwater data and ii) running the software in the forward
mode, and iii) adjusting the net rainfall infiltration level until
you find the maximum level allowable such that none of the COCs
cause a risk limit exceedance at the point of exposure. This
final rainfall infiltration rate is the maximum seepage that can
be allowed by a site cover. This level represents the rate
up to which the site cover can leak before it poses a problem.
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4. How is the Upper Confidence Limit (UCL) calculated?
The general
equation for the upper confidence limit is as follows
UCL =
mean + (standard deviation * t statistic)
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5. What do the flags NA, NC, >, #VALUE and DIV/0!
mean?
Users
of the RBCA Tool Kit may see the following flags in their results.
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Value
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Explanation |
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The
NA value indicates that this pathway was not selected
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The
NC value indicates that there is a parameter missing, and
so the value was not calculated. The most common cause of
this error is missing toxicity values for one of the chemicals
of concern.
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This
flag indicates that the PCL exceeds the solubility for that
particular chemical in the media of interest (air or water).
This suggests that a risk-based standard cannot be applied
for this chemical using the ASTM RBCA methodology.
This
is a fairly common flag. When you get it, you will want
to address other issues, such as non-aqueous phase liquids
(NAPLs) or other standards, such as aesthetic concerns or
local regulations.
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This
flag indicates a problem with one or several of your input
parameters, so that a divide by zero error was generated.
Check your inputs. Common causes of this error include missing
toxicity values for one of the chemicals of concern or a zero
value in the rate constant in the SAM model.
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#VALUE!
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This
flag indicates a problem with one or several of your input
parameters. Check your input values.
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6. How do I correctly input the affected soil zone and depth
to water for the Soil Leaching to Groundwater pathway?
A common
misunderstanding we have encountered is in the soil source zone
characteristics with regards to the affected soil zone.
Some
users have inserted values for the affected soil zone and depth
to water indicating that the affected soil is below the water level.
This can lead to miscalculations in the soil leaching to groundwater
pathway. The base of the affected soil should be above the top of
the water bearing unit.
We suggest
that you change your input to correct this error.
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7. On the Soil Parameters screen, why are there two input values
for the affected soil area and the length parallel to the wind direction?
There
has been some confusion with regards to the affected soil area and
the length parallel to the wind direction in the Soil Parameters
section. In both the RBCA Tool Kit and the RBCA Tool Kit for TRRP,
the Soil Parameter screen looks like this...

click on image for a larger version
The confusion
lies in the left-hand column of entries where there are two input
values for the affected soil area and the length of soil parallel
to the assumed wind direction. The reason for the two different
inputs is because those values may differ for those calculating
risk under the construction worker scenario. The right side values
are for the construction worker, while the left side values are
for the general case. These numbers may be different for a construction
worker, who could be in closer contact with the soil than a normal
commercial or residential receptor.
The construction
worker scenario appeared in the draft of the ASTM RBCA standard,
but not in the finalized version. It is included in the RBCA Tool
Kit as an additional receptor type available to the user.
This
two value types are indicated at the top of the number columns (circled
in the screen shot above in red). However, the column headers are
grayed out on the screen, and the purpose of the two different values
was not clearly explained in the manual.
Similarly,
the purpose for the two values in the volumetric water/air content
in part 2: Surface Soil Column, is to differentiate between the
vadose zone and the capillary fringe.
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8. What is the equation for groundwater to surface water dilution?
The equation
for groundwater to surface water dilution is as follows:
DFgw-sw
= (1 + (Qsw/(Vgw*dsw*Wgwsw))-1
Where
Qsw
= surface water flowrate at groundwater to surface water discharge
(cm3/s)
Vgw
= groundwater darcy velocity (cm/s)
dsw=
thickness of affected groundwater to surface water discharge (cm)
Wgwsw
= Width of groundwater to surface water discharge (cm)
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9. Why are the values I get
for soil volatilization different from the ASTM standard (PS-104-98)?
Several discrepancies have been noted in comparing the RBCA Tool
Kit against values published in the ASTM Tier 1 RBSL Tables. The
known discrepancies that we are aware of are generally related
to errors or omissions in the ASTM calculations or Standard (PS-104-98)
and have, for the most part, been attributed to one of the following
issues:
1)
While the equations in the ASTM standard correctly impose a mass
balance constraint on the surface soil volatilization factor (VFss),
the ASTM standard incorrectly fails to account for mass balance
constraints for volatilization from subsurface soils (VFsamb and
VFsesp). These mass balance constraints are incorporated into the
RBCA Tool Kit to prevent the gross overprediction of sustained volatilization
rates. Please see equations CM-3b and CM-4b on page B-3, and the
associated text on pages B-5 and B-6 of the RBCA Tool Kit manual.
2) The ASTM calculations for the air pathways use Inhalation
Reference Doses and Slope Factors which were derived, assuming a
20 m3/day air inhalation rate, from Inhalation Reference Concentrations
and Unit Risk Factors published in IRIS, HEAST, etc. However, the
ASTM default indoor air inhalation rate is 15 m3/day. Therefore,
the correct Inhalation Reference Doses and Slope Factors would be
different for indoor vs. outdoor inhalation. The RBCA Tool Kit (correctly)
uses the actual Inhalation Reference Concentrations and Unit Risk
Factors, as recommended by the US EPA, and as presented in the equations
for Air Exposure on Table A.2 (page A-12/13) of the RBCA Tool Kit
Manual.
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10. Why are the saved input parameters different from what
I put into the RBCA Tool Kit?
Some users outside of the United States have reported problems loading
and saving RBCA Tool Kit data files. Specifically, when Windows
is configured to use the "," (comma) for the decimal and the "."
(period) for the digit grouping symbol, then values for some input
parameters may be corrupted when data is saved or loaded into the
RBCA Tool Kit, depending on the particular language/version combination
of Windows and Excel (e.g. English Windows NT 4.0 with Portuguese
Excel 97, etc.)
It was determined that this problem does not occur when the "Regional
Settings" feature in Windows is set to "English (United States)".
To access this feature, choose Settings, then Control Panel, from
the Windows "Start" button. In the Control Panel window, open Regional
Settings and choose "English (United States)". Alternatively, the
Regional Settings language/country setting may be left as is, and
under the "Number" tab choose "." (period) for the decimal symbol
and "," (comma) for the digit grouping symbol.
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11. Why does Excel crash upon clicking
"Air Parameters"?
On
some computers, clicking "Air Parameters" on the Main Screen may
consistently result in an Excel application crash following a message
that the application (Excel) has performed an illegal operation.
If this occurs, unsaved data in any Excel workbooks will be lost.
This
problem does not occur while Excel's Visual Basic Editor application
is running. If the problem occurs, restart Excel and the RBCA
Tool Kit. Before beginning to work with the RBCA Tool Kit,
select "Visual Basic Editor" from the Macros selection in
the Tools menu or, alternatively, press Alt+F11 on the keyboard
to invoke the Visual Basic Editor application. Then return
to Excel (via the Task Bar, Alt+F11, Alt+Tab, or clicking the appropriate
window) and proceed to work as usual with the RBCA Tool Kit.
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12. How do I modify the Air Inhalation Rates?
The
input cells for air inhalation rates have been removed from versions
1.1 and greater because those parameters are not used in any calculations.
Users of version 1.0a may observe that air pathway risks or cleanup
standards did not change when varying the inhalation rates.
In
the RBCA Tool Kit for Chemical Releases, the air inhalation pathway
calculations are based on reference concentrations, as opposed
to reference doses for non-carcinogens, and unit risk
factors, as opposed to slope factors for carcinogens
(please see the air pathway equations on page A-12 of the software
manual). These are the inhalation toxicity parameters actually
measured for each COC in toxicological studies and reported by EPA
in IRIS, HEAST, etc. These values are independent of inhalation
rates and body weight. Converting reference concentrations to reference
doses or unit risk factors to slope factors requires assumptions
regarding inhalation rates and body weight (typically the RME values).
Thus, whenever you see an inhalation reference dose or slope factor,
implicit assumptions regarding inhalation rates and body weight
have already been make in order to calculate that value.
Although
the calculations in the RBCA Tool Kit make no assumption with regard
to inhalation rates, in essence you can account for varying
assumed rates by scaling the exposure duration or exposure frequency
parameters by the corresponding factors. For example, if you
wanted to assume an inhalation rate of 15 m3/day, as
opposed to a 20 m3day RME value, you could scale the
default exposure frequency of 350 days/yr to (350*15/20)=262.5 days/yr
to account for an equivalent reduction in inhalation exposure, based
on the measured reference concentration or unit risk factor.
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CHEMICAL
DATABASE
1. Can I have multiple customized chemical databases?
How can I keep my custom chemical database if I have to reinstall
the RBCA Tool Kit?
Users
of the RBCA Tool Kit may wish to note that it is possible to keep
multiple customized chemical databases, which is useful for those
who perform risk assessments in locations with different regulatory
standards.
The customized
chemical database is stored in a file called "UserChemTox.xls".
Users who wish to keep multiple databases can rename this file with
a meaningful name after use. The RBCA Tool Kit only accesses the
file UserChemTox.xls for all of its custom information, so the storage
files must be renamed whenever you switch custom databases.
There
are no plans to implement the direct support of multiple custom
databases in the RBCA Tool Kit at this time.
For users
who have to reinstall the RBCA Tool Kit, it is also worth noting
that you can move the UserChemTox.xls file to another location in
order to preserve the data when reinstalling. After installation
is complete, the user must move the UserChemTox.xls file back into
the RBCA Tool Kit folder.
There
are additional problems that occur when you attempt to use multiple
chemical databases. This issue is being addressed by the developers
for the next edition of the RBCA Tool Kit.
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2. I would like to make calculations for chemical "X",
but it is not in the chemical database. What are the chemical properties
for that chemical and how do I add it to the database?
The chemical
database included with the RBCA Tool Kit was as complete as we could
make it while maintaining proper citations. Any chemicals not listed
in the RBCA Tool Kit database must be added by the user.
For various
reasons, we do not typically grant user requests for chemical information.
However, the following link to the US EPA IRIS database may help
you out:
http://www.epa.gov/iriswebp/iris/index.aspl
The instructions
for customizing the chemical database are on pages 16-17 of the
RBCA Tool Kit manual, or on pages 19-20 of the RBCA Tool Kit for
TRRP manual.
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CONTACT
GSI
1. How do I contact Technical Support?
Sometimes,
you just need a person to answer your question.
Technical support for GSI software products is
available on a pay-per-incident basis. "Pay-per-incident" means
that the user will be charged a one-time flat-rate fee of $50.00
for resolution of a single technical support issue. For more information,
please read our technical support policy statement.
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