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 Guidance
Documents Vapor
Intrusion
New Jersey Johnson & Ettinger Spreadsheets
Download the Spreadsheets
We recommend you download these spreadsheets to your computer before
working with them. They might not work properly if open in a Web
browser.
You will need Microsoft Excel or compatible spreadsheet software.
Be sure to configure the spreadsheet software to allow macros to
run. Otherwise, the spreadsheets' programming will not work.
The above two spreadsheets and a PDF of the instructions are also
available in a ZIP file. [zip
244 Kb]
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Instructions
Version Date: May 2006
 Alternate
Format [pdf 149 Kb]
Introduction
The New Jersey versions of the USEPA Johnson and Ettinger (J&E) Spreadsheets
are adapted from the USEPA version 3.1 spreadsheet formulations of the
Johnson and Ettinger model (see http://www.epa.gov/oswer/riskassessment/
airmodel/johnson_ettinger.htm for complete model documentation and
source spreadsheets). The GW-SCREEN and GW-ADV spreadsheets have been
adapted for New Jersey use (NJ-GW-SCREEN and NJ-GW-ADV). The following
modifications have been made to the USEPA versions of the spreadsheets:
- Additional contaminants regulated by New Jersey have been added to
the VLOOKUP database.
- Toxicity factors for several contaminants have been modified to New
Jersey-specific values in the VLOOKUP database.
- Default soil/groundwater temperature is set to 13°C.
- Default depth to groundwater is set to 11.5 feet (352.5 cm).
General Guidelines for Using the New Jersey J&E Spreadsheets
- The only J&E parameters allowed to be adjusted site-specifically
are soil texture, depth to groundwater, depth of foundation, building
air exchange rate, and the building perimeter.
- A soil/groundwater temperature of 13°C must be used.
- A directly entered value for the soil gas entry rate (Qsoil)
must be used. The default value of 5 L/min must be used unless a scaled-up
version calculated from the site-specific building perimeter is substituted.
The use of soil vapor permeabilities to estimate Qsoil is
not allowed.
- The standard values for soil properties associated with each soil
texture that are built into the spreadsheet database must be used. The
use of field or laboratory-measured values for soil moisture, soil bulk
density and soil porosity is not allowed.
- The decision to use site-specific building parameters (e.g., ventilation
rate changes, building size modifications, positive pressure controls)
and nonresidential (worker) exposure parameters would necessitate an
agreement with the property owner and the implementation of an institutional
control at the affected structure/property. Use of the model in the
evaluation of a site is subject to the review and approval of the Department.
- When the calculated acceptable groundwater concentration
is controlled by the Unit Risk Factor (i.e. the contaminant is a carcinogen),
the calculated concentration shown in the spreadsheet must be multiplied
by a child inhalation adjustment factor to obtain the final NJ Ground
Water Screening Level. The multiplication factor is 0.74 for all carcinogens
except vinyl chloride, which has a factor of 0.26.
- For benzene, ethyl benzene, toluene, and xylene, a multiplication
factor of ten may be applied to the calculated screening level to allow
for contaminant degradation.
Site-Specific Adjustments Using the New Jersey J&E Spreadsheets
Using an alternate soil texture (no soil layers) (NJ-GW-SCREEN or
NJ-GW-ADV)
- If a soil texture other than sand is to be used, collect soil core(s)
and submit samples to laboratory for texture analysis as described in
the NJ Vapor Intrusion Guidance (October 2005).
At least 75% of the soil vertical profile must be as fine as the selected
alternate texture.
- Select the appropriate soil texture in the spreadsheet.
- Select the built-in soil properties for the soil texture.
Using site-specific soil texture layers (NJ-GW-ADV spreadsheet only)
- Layers must be continuous across the site and may not be fractured,
as demonstrated by soil borings.
- Enter the depth range of each soil layer in the advanced version
of J&E spreadsheet (NJ-GW-ADV). Select the built-in soil properties
for each layer.
Modifying the depth to ground water and/or the depth of the foundation
(NJ-GW-SCREEN or NJ-GW-ADV)
- Enter the depth of foundation and/or the depth of water table on
either the screening (NJ-GW-SCREEN) or advanced (NJ-GW-ADV) spreadsheet.
If the depth of the foundation (bottom of the enclosed space floor)
is a value other than 15 cm (slab) or 200 cm (basement), the NJ-GW-ADV
model must be used.
Adjustment of Building Air Exchange Rate (NJ-GW-ADV spreadsheet only)
- Enter the site-specific air exchange rate (hr-1) in the advanced
spreadsheet (NJ-GW-ADV). The air exchange rate of the lowest floor of
the building should be used.
Adjustment of Building Perimeter (NJ-GW-ADV spreadsheet only)
- Measure building perimeter in cm. If the height of the lowest floor
of the building is greater than 366 cm (12 feet), measure the height
of this floor in cm.
- Calculate a site-specific value for the soil gas entry rate Qsoil
using the following equation: Qsoil (L/min)= 5 L/min x Perimeter (cm)/4000
cm
- Enter Qsoil and Perimeter in J&E advanced spreadsheet
- The height of lowest floor of the building may also be entered if
it is greater than 366 cm.
Adjusting toxicity factors and exposure assumptions
- Toxicity factors: After consultation with the Environmental Toxicology
and Risk Assessment (ETRA) unit of the NJDEP, new IRIS or USEPA Region
III RBC table toxicity factors, that have not yet been reflected in
the most recent NJDEP vapor intrusion guidance document, may be used.
The chemical properties database in the spreadsheet must be modified
with the new values for the Reference Concentration (RfC) and/or the
Unit Risk Factor (URF).
- Use of a worker scenario allows for the following changes in exposure
assumptions:
- Elimination the of child adjustment factor (0.74)
- The exposure duration may be modified to 25 years
- The exposure frequency may be modified to 250 days/year
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