14006 Classic Coffee Rqt Add Assessment 20120501

1646 Mail Service Center, Raleigh, North Carolina 27699-1646
Phone: [phone] \ FAX: [phone] \ Internet: www.wastenotnc.org
An Equal Opportunity \ Affirmative Action Employer

May 1, 2012

Sent Via E-mail

Victor Kung
Pearl Pacific Properties, LLC
1016 Montana Drive
Charlotte, NC 28216
[e-mail]

Subject: Request for Additional Assessment
Classic Coffee Concepts
1016 & 1024 Montana Drive
Charlotte, Mecklenburg County
Brownfields Project Number 14006-10-60

Dear Mr. Kung:

The North Carolina Department of Environmental and Natural Resources (DENR) has reviewed the
recently submitted Report of Environmental Assessment prepared by AMEC dated March 16, 2012. Based on the
report and recent public meeting held on April 23, 2012, we have determined that additional assessment is necessary
to complete the brownfields risk assessment.
• General: The most recent Inactive Hazardous Sites Program Guidelines for Assessment and Cleanup
should be followed (http://portal.ncdenr.org/web/wm/sf/ihs/ihsguide), which in turn relies upon EPA's
Environmental Investigations Standard Operating Procedures and Quality Assurance Manual. Request Level 2
QA/QC data packages from a N.C. certified environmental laboratory.
• Stream Sampling: The Brownfields program is requesting that a thorough assessment of volatile organic
and inorganic compound contaminant in surface water and sediment be conducted for Stewart Creek near the
subject property. The objective of this assessment is to address community concerns about possible contamination
of the creek and resulting human health risk caused by groundwater contamination at the Classic Coffee Concepts
property. Collect surface water and sediment samples from Stewart Creek during ambient flow conditions. If
possible, collect an upstream location on the adjacent property also owned by Pearl Pacific Properties. See the
attached map for approximate sample locations and make field adjustments, as needed. Collect field parameters for
temperature, dissolved oxygen, pH, turbidity, and conductivity. Stream sampling methods should be consistent with
Mecklenburg County Land Use and Environmental Services Agency (LUESA), Water Quality Program Standard
Operating Procedure for Direct Grab Surface Water Sample Collection, guidance document is attached.
• Indoor Air Sampling: Collect indoor air samples. Submit a work plan for review prior to conducting field
work for approval by DENR. Methods should be used that are consistent with the following guidelines and
information:
9 EPA Compendium Method TO-15 (EPA/625/R-96-010b). (8- 24 hour sample duration).
North Carolina Department of Environment and Natural Resources
Dexter Matthews, Director Division of Waste Management Beverly Eaves Perdue, Governor
Dee Freeman, Secretary

May 1, 2012
Page 2 of 2

9 Section 3.0 of the “Assessment of Vapor Intrusion in Homes near the Raymark Superfund Site Using
Basement and Sub-Slab Air Samples”.
9 DRAFT Vapor Intrusion Guidance, NCDENR Brownfields Program March 2012(attached)
• Laboratory Analyses: Submit samples to a NC-certified laboratory. Ensure laboratory method detection
limits are below applicable standards. Provide complete original laboratory reports and associated laboratory
QA/QC documentation in the final report to DENR.
• Surface Water: Analyze surface water samples for the following: volatile organic compounds
(VOCs) by EPA Methods 8260, semi-volatile organic compounds (SVOCs) by EPA Method 8270, and metals
(antimony, arsenic, beryllium, cadmium, chromium (trivalent and hexavalent), copper, lead, manganese, mercury,
nickel, selenium, silver, thallium, and zinc, (see section A.7.1.2 of the Inactive Hazardous Sites Guidance
referenced above). In addition, include the following tests: Fecal Coliform Bacteria, E-Coli Bacteria, Enterococcus
Bacteria, Ammonia Nitrogen, Nitrate + Nitrite, Total Kjeldahl Nitrogen, Total Phosphorus, Total Suspended Solids
(TSS), USGS Suspended Sediment Concentration (SSC) Test, Turbidity (Lab), Hardness, Biochemical Oxygen
Demand, Chemical Oxygen Demand, and Oil and Grease (HEM)
• Sediment: volatile organic compounds (VOCs) by EPA Methods 8260, semi-volatile organic
compounds (SVOCs) by EPA Method 8270, and metals (antimony, arsenic, beryllium, cadmium, chromium
(trivalent and hexavalent), copper, lead, manganese, mercury, nickel, selenium, silver, thallium, and zinc, and
Polycyclic Aromatic Hydrocarbons (PAH)
• Vapor: Analyze vapor samples by TO-15 Method.
• Report and Figures: Submit an assessment report with a description of field activities, tabulated data
(including historical data), the laboratory data packet, and information requested in above bullets. Provide a site
plan with well locations, stream sample location, estimated locations of previous soil boring, and current site
structures. Provide summary analytical table for contaminant detected by the laboratory versus the state standard
and include historical data, if available.
Please have your environmental consultant contact me to discuss this work plan. Once these activities are
complete, we will determine if any additional information is needed to complete our evaluation of site risks and
preparation of the draft Brownfields Agreement.
Sincerely,
Carolyn Minnich
Carolyn F. Minnich
Brownfields Project Manager
Division of Waste Management

Enclosures

cc: Project File

ec: Bruce Nicholson, DENR
Will Service, DENR
Lisa Corbitt, LUESA
Rusty Rozzelle, LUESA
Rob Foster, AMEC

DRAFT
Vapor Intrusion Guidelines
of the
Brownfields Program
Division of Waste Management
NCDENR
March 2012

Intended Use

This document was developed for use by DWM Brownfields Project Managers, and
Prospective Developers of Brownfields properties and their consultants to assist with
investigation and mitigation of vapor intrusion into buildings on Brownfields projects.

Vapor Intrusion Screening

Vapor intrusion screening should be a step-wise process. At most sites contaminants are
volatilized from groundwater, move through the vadose zone, collect beneath a building
slab, and enter the building through the building slab or foundation. Screening should
follow the same path. Assessment should begin with groundwater. If groundwater
contaminant concentrations exceed vapor intrusion screening levels, soil vapor should be
assessed. If contaminant concentrations in soil gas exceed vapor intrusion screening
levels, indoor air should be assessed. On some projects, the developer and project
manager may agree to forgo some of the assessment steps and proceed directly to vapor
intrusion mitigation, which will still require some form of assessment to verify adequate
mitigation system performance. Modifying this stepwise process for other reasons should
be done only when dictated by exceptional circumstances.

Step 1. Groundwater Screening

Migration of vapor contaminants into indoor air should be considered for Brownfields
projects whenever there are soil or groundwater contaminants present that are sufficiently
volatile and toxic to potentially create health risk for building occupants. The Division of
Waste Management (DWM) Inactive Hazardous Sites Branch (IHSB) maintains tables of
vapor intrusion screening levels which identify those contaminants and provide health
based screening concentrations for vapor intrusion for groundwater, soil gas and indoor
air in residential and industrial environments.

Project managers should follow these steps to screen groundwater for potential vapor
intrusion issues:

1. Compare Groundwater Contamination to Appropriate Screening Values
Compare groundwater contaminant concentrations to those on the IHSB
1
Residential or Industrial/Commercial Vapor Intrusion Screening Tables
(http://portal.ncdenr.org/web/wm/sf/ihs/ihsguide). If contaminants are not
found in the IHSB tables but are present on the US EPA Regional Soil Vapor
and Indoor Air Screening Tables
(http://www.epa.gov/reg3hwmd/risk/human/rb-
concentration_table/Generic_Tables/index.htm), see the program toxicologist
for calculation of a groundwater screening concentration. Use the more
conservative Residential Screening Concentrations if proposed use for the site
is mixed residential/industrial, if site use will involve repeated and prolonged
use by children (e.g., school, daycare, camp), or if final use is uncertain.
2. Consider the Building Footprint. If groundwater contaminant concentrations
exceed the appropriate IHSB vapor intrusion screening concentrations and if
any of the existing or proposed buildings on the site are within 100 feet of the
contaminant plume1,2, soil vapor or sub-slab soil vapor monitoring should be
conducted. If groundwater concentrations are below the IHSB screening
concentrations, and the contaminants are not present in soil, or if there are no
existing or proposed buildings within 100 feet of the contaminant plume1,
vapor intrusion need not be considered.
3. Consider Soil Contaminants. If contaminants listed on the IHSB vapor
intrusion screening tables are present in soil but are not present in
groundwater, consideration for vapor assessment and/or monitoring should be
made on a site-specific basis.
4. Consider off-Property Receptors. Determine if there are off-property
receptors through site visits and receptor survey. Vapor intrusion screening
for off-property receptors should be considered using a similar technical basis
to those on-property. However, source attribution may also become an
important factor in determining the need for off-property screening.
Decisions about off-site VI screening should be reviewed by the NCBP
Program Manager.
Footnotes
1. Project managers may use site-specific information to adjust the default
plume-to-building screening distance (100 feet). Variables such as plume
flow direction, geological conditions (e.g., fractured rock), depth to
groundwater, plume depth (with presence of a clean groundwater lens above),
soil porosity, contaminant characteristics and other factors may be considered.

2. Lesser separation distances may be considered for petroleum-only
contaminant plumes.

Step 2. Soil Vapor Assessment/Screening

If groundwater screening as described above indicates additional assessment is necessary,
soil vapor assessment should be the next step. For development of vapor monitoring
plans and collection of vapor samples, contractors should use the NC DENR “Indoor Air
and Soil Vapor Sampling for Brownfields Projects Guidance” (Appendix A).

2
If existing buildings that will be used on the site are located within the default or site-
specific plume-to-building screening criteria described above, sub-slab vapor sampling
should be conducted for each building. If there are no existing buildings, soil vapor
sampling should be conducted in areas of planned building footprints. Sampling should
be conducted where vapor concentrations might be expected to be highest under the
building footprint (over the contaminant plume for example). Sub-slab soil vapor
sampling, as opposed to near–slab or soil vapor sampling from open areas is the preferred
method of collecting soil vapor samples wherever the building slab is in place.

Soil vapor test results should be compared to the appropriate IHSB residential or
industrial/commercial soil vapor screening levels as dictated by intended reuse of the
property. If soil vapor contaminants exceed the appropriate residential or
industrial/commercial screening levels indoor vapor sampling should be conducted. In
situations where there are representative sub-slab vapor data, it may be possible to apply
the default screening sub-slab-to-indoor air attenuation factor (0.1) to estimate indoor air
concentrations and the corresponding risk range for indoor exposure. If estimated
exposures are within the acceptable risk range for the project, it may be possible to rule
out the need for additional VI assessment or mitigation. This practice cannot be used
where there are near-slab soil vapor or open area soil vapor data only.

Because soil vapor contaminant distribution beneath a building slab can be expected to be
spatially variable, sample plans should provide for numerous sample locations to account
for this variability.

While indoor air sampling may be conducted concurrently with sub slab sampling, in
many circumstances it may be advisable to conduct soil vapor sampling first so that the
soil vapor data may be used to determine the need for indoor air sampling. Indoor air
sampling may not be necessary if sub-slab or soil vapor concentrations are low enough to
indicate that vapor intrusion is not a health risk issue, or if they are high enough to
suggest that vapor mitigation will be necessary. Indoor air sampling should not generally
be conducted prior to soil vapor sampling or in the absence of soil vapor data.
Generally, having sub-slab soil gas and indoor air data allows for a more thorough
evaluation of vapor intrusion risk.

Step 3. Indoor Air Vapor Assessment/Screening

If soil vapor concentrations exceed screening limits, indoor air sampling or another
means of estimating indoor air contaminant concentrations will usually be required. For
development of indoor air monitoring plans and collection of indoor air samples,
contractors should use the NC DENR “Indoor Air and Sub-Slab Soil Vapor Sampling for
Brownfields Projects Guidance” (Appendix A).

Wide temporal variability in vapor intrusion rates, and the presence of background
(indoor or ambient source) VOC’s present a challenge for collection and interpretation of
indoor air data. Reliable sub-slab vapor data is useful for assisting with differentiation of
ambient source contaminants and contaminants present as a result of soil vapor intrusion.
3
Careful cataloging of indoor contaminant sources also serves to identify indoor source
contaminants. Multiple sampling events and longer term sampling periods should
account for seasonal variation, building and mechanical systems use variation and other
factors. The end result should be adequate, repeatable human exposure data.

Indoor air test results should be compared to the appropriate IHSB residential or
industrial/commercial soil vapor screening limits. If indoor vapor concentrations exceed
the IHSB screening limits at 1.0E-06 LICR, or a non-carcinogenic hazard index of 1
(HI=1) for all detected VOC’s in combination, repeated indoor sampling should be
scheduled. Alternatively the PD may choose to forgo additional assessment and proceed
to vapor mitigation. Indoor sampling should be scheduled in accordance with the
requirements for indoor sample scheduling in Appendix A.

If repeated monitoring data indicate that indoor vapor concentrations exceed 1.0E-04
LICR, or HI=1 for all detected VOC’s in combination, vapor mitigation systems should
be put in place as described below.

Consult with the Brownfields Program toxicologist for site-specific recommendations.

Step 4. Mitigation

The objective of soil vapor mitigation is to reduce vapor intrusion rates and, as a result,
indoor exposure to volatile organic compounds.

For new and existing buildings, the default method for vapor mitigation is active sub-slab
depressurization. If a decrease of indoor vapor concentrations of less than one order of
magnitude is needed, other methods including passive sub-slab ventilation, membrane
barriers, and building ventilation may be considered.

For active sub-slab depressurization (SSD) vapor mitigation systems, plans should be
designed and sealed by a licensed Professional Engineer and should be submitted to the
Project Manager for approval prior to installation. For installation of the approved SSD
mitigation systems, use of contractors listed by the National Environmental Health
Association Radon Proficiency Program may be considered
(http://www.radongas.org/mitigation_template/NC.shtml), but installation should be
overseen by an engineer to ensure the installed system meets the sealed specified design.
SSD systems should be designed and installed using methods that are consistent with the
following guidelines and information:
• “Engineering Issue: Indoor Air Vapor Intrusion Mitigation Approaches”. US
EPA EPA/600/R-08-115. http://www.clu-in.org/download/char/600r08115.pdf
• “Guidelines For The Design, Installation, and Operation of Sub-Slab
Depressurization Systems”. Massachusetts Department of Environmental
Protection. December 1995. http://www.mass.gov/dep/cleanup/laws/ssd1e.pdf

SSD system plans should include a description of methods for initial and long-term
verification of SSD system performance using methods consistent with those described in
4
“Engineering Issue: Indoor Air Vapor Intrusion Mitigation Approaches”, including one
or more of the following:
• indoor air sampling
• pressure differential testing (see appendix D)
• maintenance, calibration, and testing of mechanical systems

For mitigation by building ventilation, the specifications for building ventilation should
be described in a plan prepared by a licensed Professional Engineer. The plan should
include a quantitative description of how ventilation will mitigate vapor intrusion, and
should include information such as:
• outdoor air ventilation rates
• air change rates
• designed building pressure differential
• methods for testing and verifying initial and long term ventilation system
operation and performance
• methods for performance assessment of the ventilation system to demonstrate that
the system adequately interrupts the vapor intrusion pathway

Passive barriers such as sheet membranes and/or spray-on barriers may be used to reduce
vapor intrusion for newly constructed buildings, particularly where lower rates of
attenuation of vapor intrusion (e.g., less than a single order of magnitude reduction of
indoor concentrations) are necessary. Passive barriers should be planned and installed
using methods that are consistent with those described in “Engineering Issue: Indoor Air
Vapor Intrusion Mitigation Approaches”. US EPA EPA/600/R-08-115. Passive barrier
performance must be verified by vapor monitoring.

Sealing of slab cracks, utility penetrations, sumps, drains and other slab openings is an
effective and necessary means of enhancing performance of sub-slab depressurizations
systems. Slab sealing as a means of inhibiting vapor intrusion is generally not effective
when used in the absence of depressurization systems. Slab sealing should not be used as
a standalone mitigation method when significant vapor intrusion reduction is needed.

5

Appendix A

Indoor Air and Soil Vapor Sampling for Brownfields Projects
Guidance

Objectives:
1. To provide guidelines for information gathering during indoor air (IA) and soil
vapor (SSV) sampling for Brownfields Project (BFP) vapor intrusion assessment.
2. To provide guidelines for creating worse case vapor intrusion conditions during
BFP vapor intrusion sampling.
3. To develop information about environmental conditions, building characteristics
and building ventilation during a BFP indoor air sampling event, in order to judge
how those variables might affect IA and SSV results.

Application
This information should be used as a guideline for data and information gathering
during indoor air and sub-slab soil vapor sampling for vapor intrusion assessment.
This information should be used to judge the degree of variability in indoor
ventilation and other conditions that might be anticipated in the building in question
and whether worst-case conditions for vapor intrusion were in place during the
sampling event.

Sampling and Analysis Methods
For indoor vapor, outdoor vapor (background), and sub-slab soil vapor sampling,
methods should be used that are consistent with the following guidelines and information:
• EPA Compendium Method TO-15 (EPA/625/R-96-010b)
http://www.epa.gov/ttnamti1/files/ambient/airtox/to-15r.pdf
• Section 3.0 of the “Assessment of Vapor Intrusion in Homes Near the Raymark
Superfund Site Using Basement and Sub-Slab Air Samples”
(http://www.epa.gov/ada/download/reports/600R05147/600R05147-fm.pdf ).
• Appendix E of “OSWER Draft Guidance for Evaluating the Vapor Intrusion to
Indoor Air Pathway from Groundwater and Soils (Subsurface Vapor Intrusion
Guidance)”
Methods described by the contractor in a work plan and approved by NC DENR
Brownfields Program.

Soil Vapor Sample Leak Detection
For soil vapor sampling, a tracer gas such as helium should be used to detect leakage of
ambient air into the soil vapor sample. A shroud should be placed over the sample probe
into which the tracer gas is introduced prior to sampling. Air should be drawn from the
sample zone and analyzed for the presence of tracer gas using a direct reading monitor.
The presence of a tracer gas in the sample zone indicates leakage of ambient air into the
6
sample probe. Leakage should be corrected prior to sampling. A concentrated tracer gas
atmosphere should then be maintained, measured and recorded (mean concentration for
the sample period) in the shroud during the soil vapor sampling period. The tracer gas
should be among the analytes measured in the sample submitted to the laboratory. If the
measured tracer gas in the sample is more than 10% of the mean concentration measured
in the shroud, the sample should be considered invalid as a result of ambient air leakage
into the soil vapor sample.

Sample Periods
Longer sample duration in indoor sampling allows for averaging of wide temporal
variation in indoor air contaminant concentrations. Indoor air sampling should be done
so that the longest possible sample times may be used, such as 8 hours for Suma canister
sampling. Passive samplers may be advisable in some situations because they may allow
for sample times of days or even weeks. See also Appendix C, “Radon Sampling to
Estimate Sub-Slab to Indoor Air Attenuation Factors”.

For sub-slab or soil vapor sampling, shorter sample durations may be used (e.g., less
than one hour) which will allow for efficient use of tracer gasses for leak testing.

Sampling Schedules
When multiple indoor sampling events are planned, sampling should be scheduled to
account for seasonal effects on sample results. Sampling should be conducted once
during the winter (December 15 to February 15) and once during the summer (June 15 to
August 15). For winter sampling, the high temperature for the day when samples are
collected should be no more than 5 degrees Fahrenheit (f) warmer than the mean average
high temperature for that date at the sampling location. For summer sampling, the high
temperature for the date of sampling should be no more than 5 degrees f cooler than the
average high for that date at the sampling location.

Work Plan Submittal
Prior to the start of any sampling, assessment or mitigation activity related to vapor
intrusion, a work plan should be submitted to the DENR Brownfields program. No work
should begin until that work plan has been approved in writing by the DENR
Brownfields Project Manager.

7

Appendix B

Vapor Intrusion Sampling Checklist

Weather

*Temperature
• Measure ambient temperature near the start of the sampling period, near the
middle of the sampling period, and near the end of sampling period.

*Precipitation
• Report recent precipitation trends and conditions during sampling.

Building
*Floor plan with sample locations
• Report indoor air sample locations relative to sub slab sample locations, HVAC
system zones, and local exhaust ventilation systems. (In addition to spatial
relationship to soil vapor data.)
• Report building floor area and volume.
• Report if the building is vacant with no operable systems.

Natural ventilation
Operable windows and doors, and other openings in the building envelope.
• Report size and locations of operable doors and windows.

Windows and doors, and other openings in the building envelope should be
closed during the sampling period.

Heating, ventilating and air conditioning (HVAC) system
HVAC systems
• Provide mechanical drawings for HVAC system that include air handling unit
(AHU) location and AHU service area.
• Describe blower operation (cycled or continuous).
• Describe mechanical outdoor air ventilation that is provided through the HVAC
system including the outdoor air ventilation (OAV) rate in cubic feet per
minute(describe whether the designed or measured rate is provided).

8
If the OAV rate is variable, the OAV control should be set to minimum
during sampling. The cooling or heating system should be operational
during sampling.

Exhaust ventilation
Whole building exhaust ventilation (including appliances and fireplaces).
• Provide the volumetric flow rate (designed/measured)
• Is there a makeup air source?
• Consult with BFP manager about whether to operate the system during sampling.

Large whole building exhaust ventilation systems may depressurize the building if
there is not adequate makeup air, which could increase vapor intrusion rates.
The same circumstances could create increased air change rates, particularly if
there is adequate makeup air, which would minimize building depressurization,
and could reduce indoor vapor concentrations significantly. Consider whether to
operate the system during sampling on a case by case basis.

Local exhaust ventilation
• Provide the volumetric flow rate (designed/measured)
• Is there a makeup air source?

Operation of exhaust systems may depressurize the building, particularly where
there is no provision for makeup air, and may create a worse case condition.
Alternatively, exhaust ventilation may increase air change rates which could
reduce VOC concentration.

Indoor VOC sources
• Identify and catalog indoor sources of volatile organic compounds that could
influence indoor vapor sample results. Provide locations of sources on building
floor plan in relation to sample locations.

Outdoor air background sampling
• Outdoor or background sampling should be done concurrently with IA sampling.
• Outdoor samples should be collected upwind of the buildings where sampling is
being conducted.

*Information required for sub-slab vapor sampling.

9

Appendix C

Radon Sampling to Estimate Sub-Slab to Indoor Air
Attenuation Factors

Concurrent measurement of sub-slab and indoor air radon gas concentrations may be
used in order to estimate building specific sub-slab to indoor air attenuation factors.
Radon measurement may be particularly useful where indoor sources of contaminants of
concern make it difficult to determine the proportion of indoor air contamination that is
attributable to vapor intrusion.

The following procedures should be followed when using radon concentrations to
estimate a building specific sub-slab to indoor air attenuation factor.

• Sub-slab sample procedures outlined Appendix A of these guidelines should be
followed for preparation of the sub-slab sampling point when preparing to collect
sub-slab radon gas samples.
• Sub-slab radon gas samples should be collected using “Pump/Collapsible Bag
Devices” protocols described “Indoor Radon and Radon Decay Product
Measurement Device Protocols”. 1
• Grab sampling should be used for sub-slab radon sampling. Sorbent samples
should not be used for sub-slab radon sampling.
• Indoor air sampling procedures outlined in Appendix A of these guidelines should
be followed when collecting indoor air radon samples.
• In order to account for variability in indoor radon concentrations caused by
building use and ventilation operations changes in the building, and in order to
provide a conservative attenuation factor estimate, indoor radon sampling should
be conducted under conditions that approximate worst case conditions for radon
and vapor intrusion into the building. Methods for approximating worst case
conditions for indoor sampling are described in Appendix Bof these guidelines.
• Indoor and sub-slab sampling radon should be conducted concurrently, though
indoor radon sampling periods may extend into days or weeks while sub-slsb
sampling periods will usually be eight hours or less.
• The number and location of sub-slab samples should be chosen on the basis of
site-specific parameters and objectives. Sub-slab samples should generally be
collected from locations where there is exposure concern (e.g., occupied spaces),
and in proximity to the spatial extent of groundwater or soil contamination.
• The mean of sub-slab radon concentrations should be divided by the mean of
indoor radon concentrations in order to estimate the sub-slab to indoor air
attenuation factor.
10
• Sub-slab vapor concentrations obtained from sub-slab sampling may be
multiplied by the estimated attenuation factor in order to estimate an indoor air
concentration resulting from vapor intrusion.
• If indoor vapor concentrations, estimated using a radon derived attenuation factor,
are less than indoor screening limits at the 1E-6 lifetime incremental risk (LICR)
or Hazard Quotient =1, and if DENR is satisfied that with sampling conditions
and methods, then the vapor intrusion pathway may be considered incomplete.

REFERENCES

1. USEPA, EPA 402-R-92-004, July 1992. Office of Air and Radiation: “Indoor
Radon and Radon Decay Product Measurement Device Protocols “.
http://www.epa.gov/radon/pubs/devprot3.html#2.6

11

Appendix D

Pressure Monitoring to Measure Performance of Sub-Slab
Venting/Depressurization Systems

In some circumstances it may be possible to use pressure monitoring and data logging to
measure the performance of sub-slab venting or depressurization systems. With these
systems, it is necessary to create a pressure differential between sub-slab air and indoor
air adequate to interrupt the vapor intrusion pathway. If pressure is continuously and
adequately lower in the sub-slab area than in the occupied area of the building, then air
movement - always from higher pressure to lower pressure - will be from the occupied
space to the sub–slab region, which is opposite the direction necessary for vapor intrusion
to occur.

In most vapor mitigation systems, the pressure differential is created by mechanical
exhaust ventilation of the sub-slab vented area (sub-slab depressurization). In some
circumstances it may be possible to pressurize the occupied area of a building using
HVAC equipment. Although this option is generally much more expensive to operate
than a sub-slab depressurization system, it may be preferred by building operators where
continuous building pressurization is part of normal building operation. Dedicated
manometers with data loggers may be used to measure these pressure differentials to
verify adequate performance of sub-slab venting/depressurization systems.

The following are recommendations for performance monitoring of sub-slab
depressurization systems:

• Install at least one dedicated micromanometer per 500 square feet of vented floor
area. A single manometer should be used to measure the sub-slab/indoor pressure
differential. Manometers should be sensitive to plus/minus 0.1 Pascal (Pa.).

• A minimum of a 2 Pa pressure difference between the sub-slab venting space and
the indoor space directly above that point (lower pressure in the sub-slab) is
considered significant for the purpose of interrupting the vapor intrusion pathway.
In general an adequate pressure differential should be demonstrated for 95% of
the monitoring period. This percentage may be adjusted depending on the
concentration of contaminants in the sub-slab, the sensitivity of the population
exposed or other factors.

12
• Pressure monitoring data should be captured at 10 second intervals or less. Ten
second data may be averaged, and 1 to 5 minute averages should be recorded.
Pressure differentials should be presented graphically for each monitoring period.
• Monitoring should be conducted for three discreet monitoring periods, or for a
seven month continuous monitoring period.
o For three discreet monitoring periods, the first monitoring period will be
for 30 consecutive days with at least 15 of those days in July. The second
period will be for 30 consecutive days with at least 15 days in April or
October. The third monitoring period will be for 30 days with at least 10
days in January. The three monitoring periods may be conducted in any
order. Monitoring data should be reported at the end of each monitoring
period.
o Alternatively monitoring may be done continuously for a seven month
period that includes all of July and January. Data should be reported every
60 days and submitted to your NCBP Project Manager.

References

1. ASTM Designation: E 2121-03. Standard Practice for Installing Radon
Mitigation Systems in Existing Low-Rise Residential Buildings. 2003.
2. Bill Brodhead: 12th Annual International Radon Symposium in Reno, NV.
Designing Commercial Sub-Slab Depressurization Systems. 2002.
3. USEPA. EPA/600/R-08-115. Engineering Issue: Indoor Air Vapor Intrusion
Mitigation Approaches. 2008.
4. ITRC Technical and Regulatory Guidance. Vapor Intrusion Pathway: A Practical
Guideline. 2007.
5. USEPA. EPA/625/R-92/016. Radon Prevention in the Design and Construction
of Schools and other Large Buildings. 1994.
6. Massachusetts DEP. Guidelines for the Design, Installation and Operation of
Sub-Slab Depressurization Systems. 1995.
7. DJ Folkes and DW Kurz. Proceedings: Indoor Air 2002. Efficacy of Sub-Slab
Depressurization for Mitigation of Vapor Intrusion of Chlorinated Organic
Compounds. 2002.
8. Jim DiLorenzo. NARPM Presentation July 2002. Ending the Vapor Intrusion
Confusion: Practical Points for Remediation. 2002.

13

Appendix E

Vapor Intrusion Screening Limits
in Occupational Environments

With a few exceptions, the use of occupational exposure limits including OSHA
Permissible Exposure Limits (PELs), National Institute of Occupational Safety and
Health Recommended Exposure Limits (RELs), American Conference of Governmental
Industrial Hygienists Threshold Limit Values (TLVs), or other occupational exposure
limits, are not appropriate for evaluating vapor exposure resulting from vapor intrusion,
including where property reuse is industrial, for several reasons:

• Industrial and manufacturing workers tend to be healthier than the general
population, which excludes some susceptible subpopulations from those
workplace environments such as children, elderly and those with existing chronic
respiratory illness, or other existing health condtions. Industrial buildings that
include office or commercial use can be expected to have employees that are
more susceptible to exposure than manufacturing or industrial workers.
• Occupational exposure limits are a single component of exposure control
regulations in the workplace. Medical monitoring, hazard communication
training, and other requirements are placed on employers for comprehensive
exposure control in the workplace. These controls will not be in place as a result
of environmental contamination.
• Process chemicals and other chemicals used in industrial operations offer benefit
to the business and to the employee by extension. The presence of environmental
contaminants from vapor intrusion offers no benefit to the employee or the
employer.
• OSHA PEL’s are outdated standards that in many instances are not adequately
protective of human health in the workplace1.

Very specific circumstances may occur where occupational exposure limits may be
considered for evaluating vapor exposure resulting from vapor intrusion. In industrial or
commercial environments where volatile compounds are in use that have similar
toxicological properties as those presented by vapor intrusion, exposures and risk
resulting from industrial processes may overwhelm those caused by vapor intrusion. If
occupational exposure limits, rather than risk-based screening limits are to be considered
for risk management in these circumstances, the following should be documented if
occupational exposure limits are to be applied:
14
15
• A description of the chemicals in question that are used in the industrial process,
and the quantity and frequency of use of those chemicals.
• Workplace exposure monitoring or similar data to demonstrate that workplace
exposure does or is likely to overwhelm exposure caused by vapor intrusion.
• A description of the toxicity of the chemicals in question. Compounds will be
considered similarly toxic by NC DENR if they present similar risk, and have
similar toxicologic properties including carcinogenic or non-carcinogenic effects.

If NC DENR determines that the chemicals used in the industrial process are similarly
toxic and that occupational exposures are likely to be much greater than those that might
occur as a result of vapor intrusion, then vapor intrusion may be ruled out as an exposure
pathway. Deed restrictions may be necessary to ensure that building use change does not
result in conditions where VI exposure may become problematic. If building use changes
such that the similarly toxic chemical is no longer in use, the vapor intrusion risk should
be reevaluated using risk based screening limits and exposure limits, and mitigated as
needed. If material substitution for the purpose of reducing workplace hazards results in
the removal of chemicals from the workplace that are similarly toxic to environmental
contaminants, DENR may choose to forgo the requirement for reassessment of vapor
intrusion risk at that point in time. Occupational exposure limits will not be used if NC
DENR determines that the site operator has substituted for a compound that is a
contaminant of concern or has similar toxicologic properties as contaminants of concern
in order to avoid vapor intrusion assessment and/or mitigation.

With exception of situations specified above, NCDENR will use risk based screening
limits for evaluating vapor intrusion at industrial and commercial sites.

1. 54 FR 2332, Jan. 19, 1989; 54 FR 14909, April 13, 1989; 54 FR 28154, July 5,
1989]. “Industrial experience, new developments in technology and scientific
data clearly indicate that in many instances these adopted limits are not
sufficiently protective of worker health.”

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ATTACHMENT 2
STANDARD OPERATING PROCEDURE

DIRECT GRAB SURFACE
WATER SAMPLE COLLECTION

Mecklenburg County
Land Use and Environmental Services Agency
Water Quality Program

Jon Beller Sr. Environmental Specialist Project Officer
Jeff Price Environmental Analyst QA/QC Officer
Rusty Rozzelle Water Quality Program Manager

City of Charlotte
Engineering and Property Management
Storm Water Services

Steve Jadlocki

Sr. Water Quality Specialist
Daryl Hammock Water Quality Program Manager

Charlotte-Mecklenburg Storm Water Services
Charlotte, NC

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Standard Operating Procedure
Modification / Review Log

Version Eff.
Date
Author Summary of Changes Approved Date
1.0 2/26/07 Jeff Price Original Draft Jeff Price 7/27/07
1.1 1/1/08 Jeff Price Formatting changes – minor Jeff Price 1/1/08
1.2 1/1/09 Jeff Price Field Validation, minor
formatting changes.
Jeff Price 1/1/09
1.3 4/23/09 Jeff Price J. Beller comments included. Jeff Price 4/23/09
1.4 9/08/11 Jon Beller Minor updates Jeff Price 9/8/11

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1.0 Scope and Applicability

1.1 This SOP is applicable to the direct grab sample collection of representative
surface water for the analysis of chemical, physical, and bacteriological
parameters.

2.0 Summary of Method

2.1 Representative surface water samples are collected directly from either free
flowing or impounded water sources in certified clean, pre-preserved bottles
suitable for relevant laboratory analysis. All samples are submitted to a NC State
certified laboratory for the analysis and quantification of surface water
parameters.

3.0 Health and Safety Warnings

3.1 Surface water sampling poses a number of inherent risks, including steep and
hazardous terrain negotiation, deep and/or swift moving water, stinging insects
and occasional contact with wild animals. Caution should always be exercised
and personal safety considerations must be considered paramount.

3.2 Universal precautions should be exercised when exposed to urban surface waters
with unknown potential for contamination. Always wear gloves when sampling
and decontaminate hands frequently using a no-rinse hand sanitizer.

3.3 Sampling activities conducted from a boat pose additional risks related to boating
accidents and drowning. Always obey all boating safety regulations and wear
Personal Floatation Devices on-board at all times.

3.4 Sample collection containers utilized by Charlotte-Mecklenburg Storm Water
Services and the Charlotte-Mecklenburg Laboratory are pre-preserved. Some of
these containers are preserved with approximately 2ml of concentrated acid.
Caution should be taken when opening, storing and transporting these containers.
Always make sure caps a tightly screwed in place.

4.0 Interferences

4.1 Improper sample collection location. Great care must be exercised to identify a
well-mixed zone in free flowing waters so that samples are representative.

4.2 Improper sample technique. Sample bottles used in this procedure are pre-
preserved. Great care must be exercised to fill the bottles without overfilling.
Too much sample in a pre-preserved container can dilute the effectiveness of the
preservative. VOC samples must have no air bubbles trapped in the bottles.
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4.3 Always wear non-powdered gloves. Powder from the gloves can contaminate
samples. Keep in mind that protective gloves protect the sampler, not the sample.
Protective gloves are not certified-clean or sterile. Any contact with the sample or
with the sample container will potentially contaminate the sample.

4.4 Cross-contamination of samples during transport. Always place filled samples
collection bottles (samples) upright in the cooler so that the neck and cap are
above the level of the ice. Drain ice melt-water from coolers periodically to
ensure that sample bottles are not submerged.

5.0 Equipment and Supplies

5.1 The following equipment is generally needed for Direct Grab Sample Collection
of representative surface water:

• CMU Lab Chain of Custody Form (Attachment 11.1)
• CMU Sample Collection Bottle Selection Guidance Chart (Attachment 11.2)
• Certified clean, pre-preserved sample collection bottles appropriate for
intended parameter analysis (provided by CMU)
• Sample bottle self-adhesive labels
• 4-liters of lab distilled/de-ionized reagent grade water
• CMU lab sterilized buffered bacteriological blank solution
• Sharpie, pen
• Map Book
• Cooler
• Ice
• Non-Powdered Gloves
• Hip waders, rubber boots
• Hand sanitizer
• Hand-held temperature probe

6.0 Field QC Blank Collection

6.1 Label the blank bottles with the approximate Sample Collection Time (+/- 5
minutes).

6.2 Remove the cap from the distilled/de-ionized reagent grade water or the sterilized
buffered bacteriological blank solution as appropriate.

6.3 Place the blank collection bottle(s) on level, stable surface. Remove the caps and
fill the blank collection bottle(s) to the bottom of the neck or to the indicated mark
with the appropriate blank solution, approximately 80-90% full. Be careful not to
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overfill the blank collection bottles unless the blank is for VOC parameters. VOC
blanks should be overfilled as described in 9.4.

6.4 Replace the sample collection bottle cap(s). For VOC blanks, follow the cap
replacement guidance detailed in 9.5-9.7.

7.0 Chemical / Physical Direct (Grab) Sample Collection

7.1 Label the sample collection bottles with the approximate Sample Collection Time
(+/- 5 minutes).

7.2 Locate the appropriate sample site, bearing in mind the sampling considerations
outlined in 4.1 and 4.2.

Note: Make sure sampling site is located upstream of any immediate disturbance
to the stream, including the YSI probe if utilized for field measurement collection,
unless the impact of the disturbance is the reason for sampling.

7.3 Remove the sample collection bottle cap.

7.4 Tilt the sample collection bottle down at approximately 45° angle, and submerge
½ of the bottle mouth, facing upstream from where you are standing. Fill tapered
sample collection bottles to the bottom of the neck, approximately 80-90% full.
Do not “scoop” sample as this may stir the sediment on the bottom and affect
sample. Do not overfill bottle!

7.5 Hold the filled bottle upright and replace the cap.

8.0 Bacteriological Direct (Grab) Sample Collection

8.1 Carefully open the sterile sample collection bottle cap. Be sure not to contact any
inside surface of the bottle cap or the bottle. There are no longer cap tabs.

8.2 Holding the bottle by the sides, tilt the bottle at approximately 45° angle. Dip the
bottle mouth ½ submerged, upstream from where you are standing. Submerge
until the bottle is full to the indicated 100ml volume.

Note: For stream samples, do not overfill bottle. However, for lake samples fill
the bottle above the line to collect extra volume. Leave only a small headspace.
If bottles are accidentally overfilled, it is acceptable to pour out a small amount of
sample volume, just be sure not to lose the preservative/dechlor pellet or powder!

8.3 Hold the filled bottle upright and replace the cap.

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9.0 Volatile Organic Chemical (VOC) Direct (Grab) Sample Collection

9.1 Carefully open 2 sample collection bottles (vials) for each sample collected by
removing the red caps.

9.2 Tilt the base of each sample collection bottle down at approximately 45° angle.

9.3 Submerge each entire bottle in an upright position, facing upstream from where
you are standing.

9.4 Fill both VOC sample collection bottles to the top (100% full), plus a meniscus.

9.5 Hold the filled bottles upright to replace the caps.

9.6 Carefully displace excess sample water from under the cap as you tighten.

9.7 Turn the sample collection bottles upside down and check for any trapped air
bubbles under the cap or in the bottle. If any air bubbles are present, discard the
sample from the vials and repeat beginning at step 9.2.

10.0 Post-Sample Collection

11.1 Using the hand-held temperature probe, measure the water temperature directly
from the surface water source, not from the sample collection bottle.

11.2 Record the water temperature on the appropriate lab COC form.

11.3 Place all sample collection bottles (and blanks) upright in the cooler. Do not
submerge sample bottles in ice-melt water as indicated in 4.3.

11.4 Complete the COC.

11.5 Deliver all sample bottles in the cooler on ice to the CMU Lab for analysis.

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11.0 Attachments

13.1 CMU Chain of Custody Form (Example)

13.2 CMU Sample Collection Bottle Selection Guide

Attachment 2
Water Quality & Sediment Monitoring Locations on Stewart Creek
Legend:

Stream:

CMSWS Monitoring Sites
(Water Quality Only):

CMSWS Monitoring Sites
(Water Quality & Sediment):

Classic Coffee Monitoring Sites
(Water Quality & Sediment): Site #:Stewart 1
Site #:Stewart 2
Site #:Stewart 3
Site #:Stewart 4
I-85 Site #:Stewart 5
Site #:Stewart 6
Site #:Stewart 7
Site #:Stewart 8
Brookshire Freeway
8