United States
Environmental Protection
Agency
Office of Research and
Development
Washington DC 20460
EPA/600/R-98/095
August 1998
«€PA Environmental Technology
Verification Report
Soil Gas Sampling Technology
W. L. Gore & Associates, Inc.
GORE-SORBER Screening Survey
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EPA/600/R-98/095
August 1998
Environmental Technology
Verification Report
Passive Soil Gas Sampler
W. L. Gore & Associates, Inc.
GORE-SORBER® Screening Survey
Prepared by
Tetra Tech EM Inc.
591 Camino De La Reina, Suite 640
San Diego, California 92108
Contract No. 68-C5-0037
Dr. Stephen Billets
Characterization and Monitoring Branch
Environmental Sciences Division
Las Vegas, Nevada 89193-3478
National Exposure Research Laboratory
Office of Research and Development
U.S. Environmental Protection
ET
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Notice
This document was prepared for the U.S. Environmental Protection Agency s (EPA) Superfund
Innovative Technology Evaluation Program under Contract No. 68-C5-0037. The work detailed in
this document was administered by the National Exposure Research Laboratory—Environmental
Sciences Division in Las Vegas, Nevada. The document has been subjected to EPA s peer and
administrative reviews, and has been approved for publication as an EPA document. Mention of
corporation names, trade names, or commercial products does not constitute endorsement or
recommendation for use of specific products.
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, D.C. 20460
ENVIRONMENTAL TECHNOLOGY VERIFICATION PROGRAM
VERIFICATION STATEMENT
TECHNOLOGY TYPE: PASSIVE SOIL GAS SAMPLER
APPLICATION: SUBSURFACE SOIL GAS SAMPLING
TECHNOLOGY NAME: GORE-SORBER® SCREENING SURVEY PASSIVE SOIL GAS
SAMPLING SYSTEM
COMPANY: W.L. GORE & ASSOCIATES, INC.
ADDRESS: 100 CHESAPEAKE BOULEVARD
ELKTON, MARYLAND 21921
PHONE: (410) 392-7600
ETV PROGRAM DESCRIPTION
The U.S. Environmental Protection Agency (EPA) created the Environmental Technology Verification (ETV)
Program to facilitate the deployment of innovative technologies through performance verification and information
dissemination. The goal of the ETV Program is to further environmental protection by substantially accelerating the
acceptance and use of improved and cost-effective technologies. The ETV Program is intended to assist and inform
those involved in the design, distribution, permitting, and purchase of environmental technologies. This document
summarizes the results of a demonstration of the W.L. Gore & Associates, Inc., GORE-SORBER® Screening Survey
passive soil gas sampling system.
PROGRAM OPERATION
Under the ETV Program and with the full participation of the technology developer, the EPA evaluates the
performance of innovative technologies by developing demonstration plans, conducting field tests, collecting and
analyzing demonstration data, and preparing reports. The technologies are evaluated under rigorous quality
assurance (QA) protocols to ensure that data of known and adequate quality are generated and that the demonstration
results are defensible. The EPA's National Exposure Research Laboratory, which demonstrates field characterization
and monitoring technologies, selected Tetra Tech EM Inc. as the verification organization to assist in field testing
various soil and soil gas sampling technologies. This demonstration was conducted under EPA's Superfund
Innovative Technology Evaluation Program.
DEMONSTRATION DESCRIPTION
In May and June 1997, the EPA conducted a field test of the GORE-SORBER® Screening Survey passive soil gas
sampling system along with one other soil gas and four soil sampling technologies. This verification statement
focuses on the GORE-SORBER® Screening Survey passive soil gas sampling system; similar statements have been
prepared for each of the other technologies. The performance of the GORE-SORBER® Screening Survey passive
soil gas sampling system was compared to the reference sampling method, active soil gas sampling (which provides
a snapshot of the soil gas environment at the time the sample is collected). The comparison addressed three
parameters: (1) volatile organic compound (VOC) detection and quantitation, (2) sample retrieval time, and (3) cost.
Data quality indicators for precision, accuracy, representativeness, completeness, and comparability were also
assessed against project-specific QA objectives to ensure the usefulness of the data.
EPA-VS-SCM-18 The accompanying notice is an integral part of this verification statement August 1998
iii
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The GORE-SORBER® Screening Survey passive soil gas sampling system was demonstrated at two sites : the Small
Business Administration (SBA) site in Albert City, Iowa, and the Chemical Sales Company (CSC) site in Denver,
Colorado. These sites were chosen because each site exhibited a wide range of VOC concentrations and a distinct
soil type. The VOCs detected at the sites include vinyl chloride; cis-l,2-dichloroethene (cis-l,2-DCE); 1,1-
dichloroethane (1,1-DCA); 1,1,1-trichloroethane (1,1,1-TCA); trichloroethene (TCE); and tetrachloroethene
(PCE). The SBA site is composed primarily of clay soil, and the CSC site is composed primarily of medium- to
fine-grained sandy soil. A complete description of the demonstration, including a data summary and discussion
of results, is available in the report titled Environmental Technology Verification Report: Passive Soil Gas Sampler,
W.L. Gore & Associates, Inc., GORE-SORBER® Screening Survey, EPA 600/R-98/095.
TECHNOLOGY DESCRIPTION
The GORE-SORBER Screening Survey uses GORE-SORBER modules to collect soil gas samples. The GORE-
SORBER® module is a passive soil gas sampler that is designed to collect a broad range of VOCs and semivolatile
organic compounds (SVOC), including halogenated compounds, petroleum hydrocarbons, and polynuclear
aromatic hydrocarbons. A typical GORE-SORBER module contains two or more passive collection units called
sorbers. Each sorber contains an equal amount of sorbent materials (polymeric and carbonaceous resins) . These
granular adsorbent materials are used because of their affinity for a broad range of VOCs and SVOCs. The
sorbers are sheathed in the bottom of a 4-foot- long, vapor-permeable retrieval cord. The cord and the sorbers are
constructed of inert, hydrophobic, microporous GORE-TEX® expanded polytetrafluoroethene (ePTFE). The
microporous structure of ePTFE allows vapors to move freely across the membrane and onto the sorbent material.
This microporous structure also protects the granular adsorbents from physical contact with soil particulates and
water. The GORE-SORBER module is installed to a depth of 2 to 3 feet. A pilot hole is created using a slide
hammer and tile probe or hand drill (in paved areas) . The sampler is then manually inserted into the hole using
push rods. The module is retrieved by hand and must be analyzed by the developer.
VERIFICATION OF PERFORMANCE
The demonstration data indicate the follo
Survey passive soil gas sampling system:
The demonstration data indicate the following performance characteristics for the GORE-SORBER® Screening
VOC Detection and Quantisation: The GORE-SORBER® Screening Survey detected the same compounds in each
sample as the reference soil gas sampling method, as well as several VOCs that the reference method did not detect.
This performance characteristic suggests that the GORE-SORBER Screening Survey may detect VOCs that are
at lower concentrations in the subsurface than the reference soil gas sampling method can detect. The results also
indicate a general correlation between the GORE-SORBER Screening Survey and reference method data.
However, at high contaminant levels, the ratio between the mass of contaminant in soil gas detected using the
GORE-SORBER module and the concentration of contaminant in soil gas detected using the reference soil gas
sampling method decreases, suggesting that sorbent saturation may have occurred. The GORE-SORBER
Screening Survey and reference method are field screening techniques that provide only an estimate of the actual
concentration of contaminants in soil gas. Because the GORE-SORBER Screening Survey and reference method
use different techniques to collect soil gas samples, it is not expected that the two methods will provide the same
response or that the data will be directly comparable. In addition, the GORE-SORBER® Screening Survey yields
results in micrograms per sample and the reference soil gas sampling method reports results in nanograms
per liter. Therefore, a statistical analysis of the data was not performed, and interpretation of the chemical
concentration data for this demonstration is limited to qualitative observations.
Sample Retrieval Time: Installation of the GORE-SORBER® modules averaged 8.0 minutes per sampler at the SBA
site and 7.4 minutes per sampler at the CSC site. For the demonstration, the modules were left in place for
approximately 10 days. Collection of the modules required an average of 1 .9 minutes per sampler at the SBA site
and 2.4 minutes at the CSC site. Overall, installation and collection of 35 GORE-SORBER® modules at the SBA
site required 346 minutes, an average of 9.9 minutes per sample and installation and collection of 28 GORE-
SORBER® modules at the CSC site required 274 minutes, an average of 9.8 minutes per sample. The analysis and
reporting by the technology developer required 14 to 18 days from the time samples were collected until the
laboratory report was delivered. The reference soil gas method required 458 minutes to collect 35 samples at the
SBA site, an average of 13.1 minutes per sample, and 183 minutes to collect 28 samples at the CSC site, an average
EPA-VS-SCM-18 The accompanying notice is an integral part of this verification statement August 1998
iv
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of 6.5 minutes per sample. One day was required per site to analyze the samples and report the results. Based
on the demonstration results, the average sample retrieval times for the GORE-SORBER® modules were quicker
than the reference soil gas sampling method in the clay soils at the SBA site and slower than the reference sampling
method in the sandy soils at the CSC site. The results also indicate that the sample retrieval time for the GORE-
SORBER modules may be less susceptible to variations in soil type than the sample collection times for the
reference method. During sample collection using the reference active soil gas sampler, the clay soil at the SBA
site caused the system to hold its vacuum at several sampling locations; therefore, soil gas was not completely
drawn into the system for sampling. In these cases, the rod was withdrawn in additional 6-inch increments until
the vacuum was broken and the system s pressure reached equilibrium with atmospheric pressure. The vacuum
problem was not encountered in the sandy soil at the CSC site. A two-person sampling crew retrieved soil gas
samples using the GORE-SORBER Screening Survey at both the SBA and CSC sites, and a three-person sampling
and analysis crew collected and analyzed the soil gas samples using the reference soil gas sampling method at both
sites.
Cost Based on the demonstration results, the GORE-SORBER® Screening Survey cost $125 to $225 per sample
plus equipment costs of $25 to $85 per day and mobilization/demobilization costs of $200 to $600 per day.
Operating costs for the GORE-SORBER® Screening Survey ranged from $810 to $1,540 at both the clay soil site
and the sandy soil site. For this demonstration, the active soil gas sampling method was procured at a lump sum
of $4,700 per site for the collection and analysis of 40 soil gas samples at each site. Oversight costs for the active
soil gas sampling method ranged from $680 to $1,260 at the clay soil site and $480 to $910 at the sandy soil site.
A site-specific cost and performance analysis is recommended before selecting a subsurface soil gas sampling
method.
A qualitative performance assessment of the GORE-SORBER Screening Survey indicated that (1) all 63 modules
installed at the SBA and CSC sites were retrieved without sample loss, resulting in 100 percent completeness; (2)
the sampler is easy to use and requires minimal training (a 10-minute training video is available from the
developer); (3) logistical requirements for the GORE-SORBER Screening Survey require that the samplers be
installed using a manual push tool, left in place for several days, retrieved by hand, and sent to the developer for
analysis; and (4) sample handling in the field requires that sorbent be properly containerized and shipped to the
developer. Other factors that may affect the performance range of the GORE-SORBER Screening Survey but
that were not evaluated during the demonstration are sampling depth, time allowed for sampling, type and amount
of sorbent material placed in the GORE-SORBER module, and ability of vapors to move across the module
membrane.
The demonstration results indicate that the GORE-SORBER Screening Survey can provide useful, cost-effective
data for environmental problem-solving. The GORE-SORBER® modules successfully collected soil gas samples
in clay and sandy soils. The sampler provided positive identification of target compounds and may detect lower
concentrations of VOCs in the soil gas than can the reference soil gas sampling method. Based on the results of
this demonstration, there appears to be a general correlation between the GORE-SORBER® Screening Survey and
reference method data. However, at higher contaminant levels, the ratio between the mass of contaminant detected
in the soil gas using the GORE-SORBER® module and the concentration of contaminant detected using the
reference method decreases. As with any technology selected, the user must determine what is appropriate for the
application and the project data quality objectives.
GaryJ. Foley, Ph.D.
Director
National Exposure Research Laboratory
Office of Research and Development
NOTICE: EPA verifications are based on an evaluation of technology performance under specific, predetermined criteria and
appropriate quality assurance procedures. EPA makes no expressed or implied warranties as to the performance of the technology
and does not certify that a technology will always operate as verified. The end user is solely responsible for complying with any
and all applicable federal, state, and local requirements.
EPA-VS-SCM-18 The accompanying notice is an integral part of this verification statement August 1998
V
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Foreword
The U.S. Environmental Protection Agency (EPA) is charged by Congress with protecting the
nation s natural resources. Under the mandate of national environmental laws, the Agency strives to
formulate and implement actions leading to a compatible balance between human activities and the
ability of natural systems to support and nurture life. To meet this mandate, the EPA s Office of
Research and Development (ORD) provides data and science support that can be used to solve
environmental problems and to build the scientific knowledge base needed to manage our ecological
resources wisely, to understand how pollutants affect our health, and to prevent or reduce
environmental risks.
The National Exposure Research Laboratory (NERL) is the Agency s center for the investigation of
technical and management approaches for identifying and quantifying risks to human health and the
environment. Goals of the Laboratory s research program are to (1) develop and evaluate methods
and technologies for characterizing and monitoring air, soil, and water; (2) support regulatory and
policy decisions; and (3) provide the science support needed to ensure effective implementation of
environmental regulations and strategies.
The EPA s Superfund Innovative Technology Evaluation (SITE) Program evaluates technologies for
the characterization and remediation of contaminated Superfund and Resource Conservation and
Recovery Act sites. The SITE Program was created to provide reliable cost and performance data to
speed the acceptance and use of innovative remediation, characterization, and monitoring technologies
by the regulatory and user communities.
Effective measurement and monitoring technologies are needed to assess the degree of contamination
at a site, to provide data that can be used to determine the risk to public health or the environment, to
supply the necessary cost and performance data to select the most appropriate technology, and to
monitor the success or failure of a remediation process. One component of the EPA SITE Program,
the Monitoring and Measurement Technology Program, demonstrates and evaluates innovative
technologies to meet these needs.
Candidate technologies can originate from within the federal government or from the private sector.
Through the SITE Program, developers are given the opportunity to conduct a rigorous
demonstration of their technology under actual field conditions. By completing the evaluation and
distributing the results, the Agency establishes a baseline for acceptance and use of these technologies.
The Monitoring and Measurement Technology Program is managed by the ORD s Environmental
Sciences Division in Las Vegas, Nevada.
Gary Foley, Ph.D.
Director
National Exposure Research Laboratory
Office of Research and Development
VI
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Contents
Notice ii
Verification Statement iii
Foreword vi
Figures ix
Tables x
Acronyms and Abbreviations xi
Acknowledgments xii
Executive Summary xiii
Chapter 1 Introduction 1
Technology Verification Process 3
Needs Identification and Technology Selection 3
Demonstration Planning and Implementation 3
Report Preparation 4
Information Distribution 4
Demonstration Purpose 4
Chapter 2 Technology Description 5
Background 5
Components and Accessories 7
General Operating Procedures 7
Developer Contact 9
Chapter 3 Site Descriptions and Demonstration Design 10
Site Selection and Description 10
SBA Site Description 10
CSC Site Description 12
Predemonstration Sampling and Analysis 14
Demonstration Design 14
VOC Detection and Quantitation 16
Sample Retrieval Time 16
Cost 17
Deviations from the Demonstration Plan 17
Chapter 4 Description and Performance of the Reference Method 18
Background 18
Components and Accessories 18
Description of Platform 19
Demonstration Operating Procedures 19
Qualitative Performance Factors 20
Reliability and Ruggedness 20
Training Requirements and Ease of Operation 21
Logistical Requirements 21
Sample Handling 21
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Contents (Continued)
Performance Range 21
Quantitative Performance Factors 21
VOC Detection and Quantitation 22
Sample Retrieval Time 22
Data Quality 22
Chapter 5 Technology Performance 25
Qualitative Performance Factors 25
Reliability and Ruggedness 25
Training Requirements and Ease of Operation 25
Logistical Requirements 25
Sample Handling 26
Performance Range 26
Quantitative Performance Assessment 26
VOC Detection and Quantitation 26
Sample Retrieval Time 29
Data Quality 32
Chapter 6 Economic Analysis 34
Assumptions 34
GORE-SORBER® Screening Survey 34
Reference Sampling Method 36
Chapter 7 Summary of Demonstration Results 39
Chapter 8 Technology Update 41
Chapter 9 Previous Deployment 43
References 44
Appendix
A Data Summary Tables A-1
Vlll
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Figures
2-1. GORE-SORBER® Module Schematic 8
3-1. Small Business Administration Site 11
3-2. Chemical Sales Company Site 13
3-3. Typical Sampling Locations and Random Sampling Grid 15
5-1. Comparative Plot of Mean Total DCE Mass Versus Concentration 30
5-2. Comparative Plot of Mean 1,1,1-TCA Mass Versus Concentration 30
5-3. Comparative Plot of Mean TCE Mass Versus Concentration 31
5-4. Comparative Plot of Mean PCE Mass Versus Concentration 31
IX
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Tables
4-1. Volatile Organic Compound Concentrations in Samples Collected Using the
Reference Soil Gas Sampling Method 23
5-1. Volatile Organic Compound Mass in Samples Collected Using the GORE-SORBER
Screening Survey 27
5-2. Mean Chemical Concentrations of the GORE-SORBER Screening Survey and
Reference Soil Gas Sampling Method 28
5-3. Average Sample Retrieval Times for the GORE-SORBER Modules and the
Reference Soil Gas Sampling Method 32
6-1. Estimated Subsurface Soil Gas Sampling Costs for the GORE-SORBER Screening Survey 35
6-2. Estimated Subsurface Soil Gas Sampling Costs for the Reference Sampling Method .... 37
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Acronyms and Abbreviations
bgs
cc
cis-l,2-DCE
CRREL
CSC
1,1-DCA
DCE
E&E
EPA
ePTFE
ETV
ETVR
GC/MS
Gore
mg/kg
ml
*g
•g/kg
NELAC
ng/L
NERL
OU
PAH
PCE
QA
QA/QC
RCRA
RI/FS
RPD
SBA
SITE
SMC
SVE
SVOC
1,1,1-TCA
TCE
trans-1,2-DCE
VOC
below ground surface
cubic centimeter
cis-1,2-dichloroethene
Cold Regions Research Engineering Laboratory
Chemical Sales Company
1,1-dichloroethane
dichloroethene
Ecology & Environment
U.S. Environmental Protection Agency
expanded polytetrafluoroethene
Environmental Technology Verification
Environmental Technology Verification Report
gas chromatography/mass spectrometer
W.L. Gore & Associates, Inc.
milligrams per kilogram
milliliter
micrograms
micrograms per kilogram
National Environmental Laboratory Accreditation Conference
nanograms per liter
National Exposure Research Laboratory
operable unit
polynuclear aromatic hydrocarbons
tetrachloroethene
quality assurance
quality assurance/quality control
Resource Conservation and Recovery Act
remedial investigation/feasibility study
relative percent difference
Small Business Administration
Superfund Innovative Technology Evaluation
Superior Manufacturing Company
soil vapor extraction
semivolatile organic compound
1,1,1-trichloroethane
trichloroethene
trans-1,2-dichloroethene
volatile organic compound
XI
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Acknowledgments
This report was prepared for the U.S. Environmental Protection Agency s (EPA) Environmental
Technology Verification Program under the direction of Stephen Billets, Brian Schumacher, and Eric
Koglin of the EPA s National Exposure Research Laboratory—Environmental Sciences Division in
Las Vegas, Nevada. The project was also supported by the EPA s Superfund Innovative Technology
Evaluation (SITE) Program. The EPA wishes to acknowledge the support of Janice Kroone (EPA
Region 7), Joe Vranka (Colorado Department of Public Health and the Environment), Armando
Saenz (EPA Region 8), Sam Goforth (independent consultant), Alan Hewitt (Cold Regions Research
Engineering Laboratory), Bob Siegrist (Colorado School of Mines), and Ann Kern (EPA SITE
Program). In addition, we gratefully acknowledge the collection of the passive soil gas samples using
the GORE-SORBER Screening Survey by Mark Wrigley (Gore); implementation of this
demonstration by Eric Hess and John Parks (Tetra Tech); editorial and publication support by Butch
Fries, Jennifer Brainerd, and Stephanie Anderson (Tetra Tech); and technical report preparation by
Ron Ohta, Roger Argus, and Ben Hough (Tetra Tech).
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Executive Summary
In May and June 1997, the U.S. Environmental Protection Agency conducted a demonstration of the
GORE-SORBER Screening Survey, one other soil gas sampling technology, and four soil sampling
technologies. This Environmental Technology Verification Report presents the results of the GORE-
SORBER Screening Survey demonstration; similar reports have been published for each technology.
The GORE-SORBER module is a passive soil gas sampler that consists of several separate sorbent
collection units called sorbers. Each sorber contains equal quantities of sorbent materials (polymeric
and carbonaceous resins) selected for their affinity to a broad range of volatile organic compounds
(VOC) and semivolatile organic compounds, and for their hydrophobic characteristics. The sorbers
are sheathed in a vapor-permeable insertion and retrieval cord constructed of inert, hydrophobic
material that allows vapors to move freely across the membrane and onto the sorbent material and that
protects the granular adsorbents from physical contact with soil particulates and water.
The GORE-SORBER module was demonstrated at two sites: the Small Business Administration (SBA)
site in Albert City, Iowa, and the Chemical Sales Company (CSC) site in Denver, Colorado. These
sites were chosen because each exhibited a wide range of VOC concentrations and because each had a
distinct soil type. The VOCs detected at the sites include vinyl chloride; cis-l,2-dichloroethene;
trichloroethene; 1,1-dichloroethane; 1,1,1-trichloroethane; and tetrachloroethene. The SBA site is
composed primarily of clay soil, and the CSC site is composed primarily of medium- to fine-grained
sandy soil.
The GORE-SORBER Screening Survey was compared to a reference sampling method, active soil
gas sampling, in terms of the following parameters: (1) VOC detection and quantitation, (2) sample
retrieval time, and (3) cost. The demonstration data indicated the following performance
characteristics for the GORE-SORBER Screen Survey passive soil gas sampling system:
• The GORE-SORBER Screening Survey detected the same compounds as the reference
sampling method, as well as several VOCs that the reference method did not detect. The
results also indicate a general correlation between the GORE-SORBER Screening Survey and
reference sampling method data. However, at high contaminant levels, the ratio between the
mass of contaminant in soil gas detected using the GORE-SORBER module and the
concentration of contaminant in soil gas detected using the reference method decreases.
• The average sample retrieval times for the GORE-SORBER modules were quicker than the
reference soil gas sampling method in the clay soils at the SBA site and slower than the
reference sampling method in the sandy soils at the CSC site. For this demonstration, the
GORE-SORBER modules were left in place for 10 days at each site and required an average
of 16 days per site for analysis and reporting by the developer.
• Based on the demonstration results, the GORE-SORBER Screening Survey cost $125 to
$225 per sample plus equipment costs of $25 to $85 per day and mobilization/demobilization
costs of $200 to $600 per site. Operating costs for the GORE-SORBER Screening Survey
ranged from $810 to $1,540 at both the clay soil site and the sandy soil site.
In general, the results for data quality indicators selected for this demonstration met the established
quality assurance objectives and support the usefulness of the demonstration results in verifying the
GORE-SORBER Screening Survey s performance.
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Chapter 1
Introduction
Performance verification of innovative and alternative environmental technologies is an integral part
of the U.S. Environmental Protection Agency s (EPA) regulatory and research mission. Early efforts
focused on evaluating technologies that supported implementation of the Clean Air and Clean Water
Acts. To meet the needs of the hazardous waste program, the Superfund Innovative Technology
Evaluation (SITE) Program was established by the EPA Office of Solid Waste and Emergency
Response (OSWER) and Office of Research and Development (ORD) as part of the Superfund
Amendments and Reauthorization Act of 1986. The primary purpose of the SITE Program is to
promote the acceptance and use of innovative characterization, monitoring, and treatment
technologies.
The overall goal of the SITE Program is to conduct research and performance verification studies of
alternative or innovative technologies that may be used to achieve long-term protection of human
health and the environment. The various components of the SITE Program are designed to encourage
the development, demonstration, acceptance, and use of new or innovative treatment and monitoring
technologies. The program is designed to meet four primary objectives: (1) identify and remove
obstacles to the development and commercial use of alternative technologies, (2) support a
development program that identifies and nurtures emerging technologies, (3) demonstrate promising
innovative technologies to establish reliable performance and cost information for site characterization
and cleanup decision-making, and (4) develop procedures and policies that encourage the selection of
alternative technologies at Superfund sites, as well as other waste sites and commercial facilities.
The intent of a SITE demonstration is to obtain representative, high quality, performance and cost
data on innovative technologies so that potential users can assess a given technology s suitability for a
specific application. The SITE Program includes the following elements:
Monitoring and Measurement Technology (MMT) Program — Evaluates technologies that
detect, monitor, sample, and measure hazardous and toxic substances. These technologies are
expected to provide better, faster, and more cost-effective methods for producing real-time
data during site characterization and remediation studies
• Remediation Technologies — Conducts demonstrations of innovative treatment technologies
to provide reliable performance, cost, and applicability data for site cleanup
• Technology Transfer Program — Provides and disseminates technical information in the
form of updates, brochures, and other publications that promote the program and the
technology. Provides technical assistance, training, and workshops to support the technology
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The MMT Program provides developers of innovative hazardous waste measurement, monitoring,
and sampling technologies with an opportunity to demonstrate a technology s performance under
actual field conditions. These technologies may be used to detect, monitor, sample, and measure
hazardous and toxic substances in soil, sediment, waste materials, and groundwater. Technologies
include chemical sensors for in situ (in place) measurements, groundwater sampling devices, soil and
core sampling devices, soil gas samplers, laboratory and field-portable analytical equipment, and
other systems that support field sampling or data acquisition and analysis.
The MMT Program promotes the acceptance of technologies that can be used to accurately assess the
degree of contamination at a site, provide data to evaluate potential effects on human health and the
environment, apply data to assist in selecting the most appropriate cleanup action, and monitor the
effectiveness of a remediation process. Acceptance into the program places high priority on
innovative technologies that provide more cost-effective, faster, and safer methods than conventional
technologies for producing real-time or near-real-time data. These technologies are demonstrated
under field conditions and results are compiled, evaluated, published, and disseminated by ORD.
The primary objectives of the MMT Program are the following:
• Test field analytical technologies that enhance monitoring and site characterization capabilities
• Identify the performance attributes of new technologies to address field characterization and
monitoring problems in a more cost-effective and efficient manner
• Prepare protocols, guidelines, methods, and other technical publications that enhance the
acceptance of these technologies for routine use
The SITE MMT Program is administered by ORD s National Exposure Research Laboratory (NERL-
LV) at the Environmental Sciences Division in Las Vegas, Nevada.
In 1994, the EPA created the Environmental Technology Verification (ETV) Program to facilitate the
deployment of innovative technologies in other areas of environmental concern through performance
verification and information dissemination. As in the SITE Program, the goal of the ETV Program is
to further environmental protection by substantially accelerating the acceptance and use of improved
and cost-effective technologies. The ETV Program is intended to assist and inform those involved in
the design, distribution, permitting, and purchase of various environmental technologies. The ETV
Program capitalizes on and applies the lessons learned in implementing the SITE Program.
For each demonstration, the EPA draws on the expertise of partner "verification organizations" to
design efficient procedures for conducting performance tests of environmental technologies. The
EPA selects its partners from both the public and private sectors, including federal laboratories,
states, universities, and private sector entities. Verification organizations oversee and report
verification activities based on testing and quality assurance (QA) protocols developed with input
from all major stakeholder and customer groups associated with the technology area. For this
demonstration, the EPA selected Tetra Tech EM Inc. (Tetra Tech; formerly PRC Environmental
Management, Inc.) as the verification organization.
In May and June 1997, the EPA conducted a demonstration, funded by the SITE Program, to verify
the performance of four soil and two soil gas sampling technologies: SimulProbe® Technologies, Inc.
Core Barrel Sampler; Geoprobe® Systems, Inc., Large-Bore Soil Sampler; AMS™ Dual Tube Liner
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Sampler; Clements Associates, Inc., Environmentalist s Subsoil Probe; Quadrel Services, Inc.,
EMFLUX® Soil Gas Investigation System; and W.L. Gore & Associates, Inc., GORE-SORBER®
Screening Survey passive soil gas sampling system. This environmental technology verification report
(ETVR) presents the results of the demonstration for one soil gas sampling technology, the GORE-
SORBER Screening Survey passive soil gas sampling system. Separate ETVRs have been published
for the remaining soil and soil gas sampling technologies.
Technology Verification Process
The technology verification process is designed to conduct demonstrations that will generate high-
quality data that the EPA and others can use to verify technology performance and cost. Four key
steps are inherent in the process: (1) needs identification and technology selection, (2) demonstration
planning and implementation, (3) report preparation, and (4) information distribution.
Needs Identification and Technology Selection
The first aspect of the technology verification process is to identify technology needs of the EPA and
the regulated community. The EPA, the U.S. Department of Energy, the U.S. Department of
Defense, industry, and state agencies are asked to identify technology needs for characterization,
sampling, and monitoring. Once a technology area is chosen, a search is conducted to identify suitable
technologies that will address that need. The technology search and identification process consists of
reviewing responses to Commerce Business Daily announcements, searches of industry and trade
publications, attendance at related conferences, and leads from technology developers. Selection of
characterization and monitoring technologies for field testing includes an evaluation of the candidate
technology against the following criteria:
• Designed for use in the field or in a mobile laboratory
• Applicable to a variety of environmentally contaminated sites
• Has potential for resolving problems for which current methods are unsatisfactory
• Has costs that are competitive with current methods
• Performs better than current methods in areas such as data quality, sample preparation, or
analytical turnaround time
• Uses techniques that are easier and safer than current methods
• Is commercially available
Demonstration Planning and Implementation
After a technology has been selected, the EPA, the verification organization, and the developer agree
to a strategy for conducting the demonstration and evaluating the technology. The following issues are
addressed at this time:
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• Identifying and defining the roles of demonstration participants, observers, and reviewers
• Identifying demonstration sites that provide the appropriate physical or chemical attributes in
the desired environmental media
• Determining logistical and support requirements (for example, field equipment, power and
water sources, mobile laboratory, or communications network)
• Arranging analytical and sampling support
• Preparing and implementing a demonstration plan that addresses the experimental design, the
sampling design, quality assurance/quality control (QA/QC), health and safety, field and
laboratory operations scheduling, data analysis procedures, and reporting requirements
Report Preparation
Each of the innovative technologies is evaluated independently and, when possible, against a reference
technology. The technologies are usually operated in the field by the developers in the presence of
independent observers. These individuals are selected by the EPA or the verification organization and
work to ensure that the technology is operated in accordance with the demonstration plan.
Demonstration data are used to evaluate the capabilities, performance, limitations, and field
applications of each technology. After the demonstration, all raw and reduced data used to evaluate
each technology are compiled into a technology evaluation report as a record of the demonstration. A
verification statement and detailed evaluation narrative of each technology are published in an ETVR.
This document receives a thorough technical and editorial review prior to publication.
Information Distribution
The goal of the information distribution strategy is to ensure that ETVRs are readily available to
interested parties through traditional data distribution pathways, such as printed documents. Related
documents and technology updates are also available on the World Wide Web through the ETV Web
site (http://www.epa.gov/etv) and through the Hazardous Waste Clean-Up Information Web site
supported by the EPA OSWER Technology Innovation Office (http://clu-in.org). Additional
information on the SITE Program can be found on ORD s web site (http://www.epa.gov/ORD/SITE).
Demonstration Purpose
The purpose of this demonstration of the GORE-SORBER Screening Survey was to evaluate how the
sampler performed relative to the reference sampling method, active soil gas sampling. Specifically,
this demonstration evaluated the GORE-SORBER Screening Survey in comparison to the reference
soil gas sampling method in terms of the following parameters: (1) volatile organic compound (VOC)
detection and quantitation, (2) sample retrieval time, and (3) cost. Data quality indicators for
precision, accuracy, representativeness, completeness, and comparability were also assessed against
established QA objectives to ensure the usefulness of the data for the purpose of this verification.
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Chapter 2
Technology Description
This chapter describes the GORE-SORBER Screening Survey, including its background, components
and accessories, and general operating procedures. The text in this chapter was provided by the
developer and was edited for format and relevance.
Background
Soil gas sampling techniques can be broadly divided into two categories: active and passive. The
active soil gas sampling method uses vacuum methods to collect soil gas samples at discrete depth
intervals and provides a "snapshot" of the soil gas environment at a particular moment and at a
specific depth. This approach requires detectable vapor-phase compound concentrations, relatively
porous subsurface soil, and experienced on-site personnel. Because the soil gas samples are usually
analyzed immediately, an on-site or nearby laboratory is typically required. Active soil gas sampling
is generally used for rapid screening of VOCs in the subsurface in moderately permeable soils and is
generally not applicable to detecting semivolatile organic compounds (SVOC).
Passive sampling techniques rely on diffusion and adsorption and can be used to sample for VOCs and
SVOCs, depending on the adsorbent selected and the diffusion membrane used. The developers of
passive soil gas samplers claim that the passive samplers allow for equilibrium to develop between the
soil gases and the sorbent over a period of several days to weeks. Further, the developers claim that
exposure of the passive samplers to the soil gas over extended periods concentrates the mass of VOCs
and SVOCs absorbed to the sampler; thereby enhancing contaminant detection sensitivity.
The GORE-SORBER Screening Survey is a passive soil gas sampling technology developed by W.L.
Gore & Associates, Inc. (Gore). The GORE-SORBER module consists of several granular adsorbent
materials housed in a chemically inert, hydrophobic, microporous GORE-TEX® expanded
polytetrafluoroethene (ePTFE) membrane. The microporous structure of ePTFE allows vapors to
move freely across the membrane and onto the sorbent material while preventing water and soil
particles from entering the sampler. GORE-SORBER and GORE-TEX® are registered trademarks of
Gore. GORE-SORBER Screening Survey is a registered service mark of Gore.
The GORE-SORBER® Screening Survey was developed to address the limitations of reference methods
(such as sensitivity to detection of SVOCs and performance under a broader range of geologic
conditions) and to improve the design limitations of existing passive collection systems, including the
quantity and type of adsorbents used, sorbent hydrophobicity, and collector installation depth. The
GORE-SORBER module was designed to sample contaminants in soil gas from open land, beneath
artificial surfacing, and under water in various terrain, weather, and soil types.
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The GORE-SORBER module is designed to identify and quantify a broad spectrum of compounds.
The developer provided the following list of target analytes that the GORE-SORBER® Screening
Survey can potentially detect:
• VOCs: vinyl chloride, methyl tert-butyl ether, 1,1-dichloroethane (1,1-DCA), chloroform,
benzene, 1,2-dichloroethane, toluene, tetrachloroethene (PCE), ethylbenzene, o-xylene,
trans-1,2-dichloroethene (trans-1,2-DCE), cis-l,2-dichloroethene (cis-l,2-DCE), 1,1,1-
trichloroethane (1,1,1-TCA), carbon tetrachloride, trichloroethene (TCE), octane,
chlorobenzene, m-,p-xylene, and ketones.
• SVOCs: 1,3,5-trimethylbenzene, 1,2,4-trimethylbenzene, 1,4-dichlorobenzene, undecane,
tridecane, pentadecane, naphthalene, 2-methylnaphthalene, acenaphthene, fluorene,
phenanthrene, anthracene, fluoranthene, and pyrene.
• Explosives: nitrobenzene, 2-nitrotoluene, 3-nitrotoluene, 4-nitrotoluene, 1,3-dinitrobenzene,
2,4-dinitrotoluene, 2,6-dinitrotoluene, 1,3,5-trinitrobenzene, 2,4,6-trinitrotoluene,
2-amino-4,6-dinitrotoluene, and 4-amino-2,6-dinitrotoluene.
• Chemical Agents/Breakdown Products: mustard (as a tentatively identified compound),
1,4-dithiane, 1,4-oxathiane, benzothiozole, p-chlorophenylmethylsulfide,
p-chlorophenylmethylsulfoxide, p-chlorophenylmethylsulfone, dimethyldisulfide, diisopropyl
methylphosphonate, dimethyl methylphosphonate, 4-chloroacetophenone, and
2-chloroacetophenone.
• Polychlorinated Biphenyls: (mono-, di-, tri, and tetra-chlorobiphenyl detection capability has
been demonstrated), and certain pesticides and herbicides.
Additional developer claims for the GORE-SORBER Screening Survey include the following:
• The data are proportionally comparable to active soil gas data
• The samplers 'detection limits for VOCs and SVOCs range from 0.01 to 0.1 micrograms (• g)
• The extended sampling time, 7 to 14 days, increases sensitivity and lowers detection limits
• No specialized training is needed to use the GORE-SORBER module
• A single GORE-SORBER module can be used to quantitate VOCs and SVOCs in vapor
pressure range from vinyl chloride up to pyrene
• The data provide positive identification of target compounds
• Nontarget compounds can be tentatively identified through library search
• The data are reproducible
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However, during the demonstration, only Gore s claims regarding the ability of the GORE-SORBER
Screening Survey to be used to sample for VOCs, sample retrieval time, and cost were evaluated.
Components and Accessories
Each module for a particular screening survey contains equal amounts of a suitable granular adsorbent
material. Specific polymeric and carbonaceous resins are selected by Gore for their affinity to a broad
range of VOCs and SVOCs, and for their hydrophobic properties. The sorbers are sheathed in the
bottom of a 4-foot-long, vapor-permeable insertion and retrieval cord. Both the retrieval cord and
sorbent container are constructed solely of inert, hydrophobic, microporous GORE-TEX® ePTFE,
similar to Teflon™ brand polytetrafluoroethene. Figure 2-1 shows a typical GORE-SORBER®
module.
The ePTFE protects the sorbent media from contact with groundwater and soil pore water without
retarding soil vapor diffusion. This characteristic of the technology facilitates its application in low
permeability and poorly drained soils.
General Operating Procedures
The following is a summary of the developer-recommended operating procedure to install and remove
a GORE-SORBER® :
1. A slam bar or electric rotary hammer-drill should be used to make a 0.5-inch to 0.75-inch-
diameter pilot hole to deploy the samplers. Although GORE-SORBER modules may be
installed to any depth, the samplers are typically installed at a depth of 2 to 3 feet below
ground surface (bgs).
2. After the pilot hole is completed, the GORE-SORBER module is removed from its reusable
storage and shipping containers and is inserted into the completed pilot holes using the
stainless-steel insertion rod supplied by the technology developer. The sorbers, which are at
the end of the GORE-SORBER module, are pushed to the bottom of the pilot hole. The top
of each GORE-SORBER module is fastened to a cork that is tamped flush with the ground
surface to seal the annulus of the hole.
3. The GORE-SORBER module is left in place for a predetermined time to allow for passive soil
gas sampling (typically 1 to 2 weeks).
4. GORE-SORBER module retrieval requires that field personnel locate the sampler, remove the
cork, grasp the retrieval cord, and manually pull the module from each location. The cork is
separated from the module and discarded. The GORE-SORBER module is resealed in
shipping vials provided by the developer and placed in the shipping cooler. The GORE-
SORBER module is returned by overnight carrier to the technology developer for laboratory
analysis. During the demonstration, the GORE-SORBER modules were immediately placed
on ice in the shipping cooler after collection. However, Gore claims that placing modules on
ice after collection is not a requirement.
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EXPANDED PTFE
INSERTION AND
RETRIEVAL CORD
EXPANDED
PTFE SORBENT
CONTAINER
GRANULAR
SORBENT
SOIL SURFACE
SEALED PINCH-
WINDOW TO RECEIVE £
INSERTION TOOL
Y
SEALED BOTTOM END
INSERTION
TOOL
a.
b.
a. GORE-SORBER®
b. GORE-SORBER® with attached insertion tool
Figure 2-1. GORE-SORBER® Module Schematic (W.L. Gore & Associates, 1997)
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Developer Contact
®
For more developer information on the GORE-SORBER Screening Survey, please refer to Chapters
8 and 9 of this ETVR or contact the developer at:
Ray Fenstermacher
W.L. Gore & Associates, Inc.
100 Chesapeake Boulevard
Elkton, Maryland 21921
Telephone: (410) 392-7600
Facsimile: (410) 506-4780
E-mail: rfenster@wlgore.com
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Chapter 3
Site Descriptions and Demonstration Design
This chapter describes the demonstration sites, predemonstration sampling and analysis, and the
demonstration design. The demonstration was conducted in accordance with the "Final Demonstration
Plan for the Evaluation of Soil Sampling and Soil Gas Sampling Technologies " (PRC, 1997).
Site Selection and Description
The following criteria were used to select the demonstration sites:
• Unimpeded access for the demonstration
• A range (micrograms per kilogram [• g/kg] to milligrams per kilogram [mg/kg]) of
chlorinated or aromatic VOC contamination in soil
• Well-characterized contamination
• Different soil textures
• Minimal underground utilities
• Situated in different climates
Based on a review of 48 candidate sites, the Small Business Administration (SBA) site in Albert City,
Iowa, and the Chemical Sales Company (CSC) site in Denver, Colorado, were selected for the
demonstration of the GORE-SORBER Screening Survey.
SBA Site Description
The SBA site is located on Orchard Street between 1st and 2nd Avenues in east-central Albert City,
Iowa (Figure 3-1). The site is the location of the former Superior Manufacturing Company (SMC)
facility and is now owned by the SBA and B&B Chlorination, Inc. SMC manufactured grease guns at
the site from 1935 until 1967. Metal working, assembling, polishing, degreasing, painting, and other
operations were carried out at the site during this period. The EPA files indicate that various solvents
were used in manufacturing grease guns and that waste metal shavings coated with oil and solvents
were placed in the former waste storage area. The oil and solvents were allowed to drain onto the
ground, and the metal waste was hauled off site by truck (Ecology & Environment [E&E], 1996).
10
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2nd Avenue
Former SMC
Waste Storage
Area
School
Bus
Storage
Building
Buena Vista
County
Maintenance
Facility
DEMONSTRATION GRID LOCATIONS
AND GRID NUMBER
APPROXIMATE SITE BOUNDARY
Figure 3-1. Small Business Administration Site
FEET
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The site consists of the former SMC plant property and waste storage yard. The SMC plant property is
currently a grass-covered, relatively flat, unfenced open lot. The plant buildings have been razed. A
pole barn is the only building currently on the plant property. Several buildings are present on the
waste storage yard, including three historic buildings: a garage, a museum, and a school house.
Poorly drained, loamy soils of the Nicollet series are present throughout the site area. The upper layer
of these soils is a black loam grading to a dark-gray loam. Below this layer, the soils grade to a friable,
light clay loam extending to a depth of 60 inches. Underlying these soils is a thick sequence (400 feet
or more) of glacial drift. The lithology of this glacial drift is generally a light yellowish-gray, sandy
clay with some gravel, pebbles, or boulders. The sand-to-clay ratio is probably variable throughout the
drift. Groundwater is encountered at about 6 to 7 feet bgs at the SBA site (E&E, 1996).
Tetrachloroethene, TCE, cis-l,2-DCE, and vinyl chloride are the primary contaminants detected in soil
at the site. These chlorinated VOCs have been detected in both surface (0 to 2 feet deep) and
subsurface (3 to 5 feet deep) soil samples. TCE and cis-l,2-DCE are the VOCs usually detected at the
highest concentrations in both soil and groundwater. In past site investigations, TCE and cis-l,2-DCE
have been detected in soils at 17 and 40 mg/kg, respectively, with vinyl chloride present at 1.4 mg/kg.
The areas of highest contamination have been found near the center of the former SMC plant property
and near the south end of the former SMC waste storage area (E&E, 1996).
CSC Site Description
The CSC site is located in Denver, Colorado, approximately 5 miles northeast of downtown Denver.
From 1962 to 1976, a warehouse at the site was used to store chemicals. The CSC purchased and first
occupied the facility in 1976. The CSC installed aboveground and underground storage tanks and
pipelines at the site between October 1976 and February 1977. From 1976 to 1992, the facility
received, blended, stored, and distributed various chemicals and acids. Chemicals were transported in
bulk to the CSC facility by train and were unloaded along railroad spurs located north and south of the
CSC facility. These operations ceased at the CSC site in 1992.
The EPA conducted several investigations of the site from 1981 through 1991. Results of these
investigations indicated a release of organic chemicals into the soil and groundwater at the site. As a
result of this finding, the CSC site was placed on the National Priorities List in 1990. The site is
divided into three operable units (OU). This demonstration was conducted at OU1, which is located at
4661 Monaco Parkway in Denver (Figure 3-2). In September 1989, EPA and CSC entered into an
Administrative Order of Consent requiring CSC to conduct a remedial investigation/feasibility study
(RI/FS) for CSC OU1. The RI/FS was completed at OU1 in 1991 (Engineering-Science, Inc., 1991).
The current site features of OU1 consist of the warehouse, a concrete containment pad with a few
remaining tanks from the aboveground tank farm, another smaller containment pad with aboveground
tanks north of a railroad spur, and multiple areas in which drums are stored on the west side of the
warehouse and in the northwest corner of the property. The warehouse is currently in use and is
occupied by Steel Works Corporation.
The topography, distribution of surficial deposits, and materials encountered during predemonstration
sampling suggest that the portion of OU1 near the CSC warehouse is a terrace deposit composed of
Slocum Alluvium beneath aeolian sand, silt, and clay. The terrace was likely formed by renewed
downcutting of a tributary to Sand Creek. Borings at the CSC property indicate that soils in the vadose
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00
SCALE
0 25 50 100
FEET
ABOVE-GROUND
TANKS
O O
O O
O O
ce
o
-ABOVE-GROUND
TANKS
ASPHALT
CHEMICAL SALES
WAREHOUSE
LEGEND
DC.
<
Q_
O
O
Figure 3-2. Chemical Sales Company Site
DEMONSTRATION GRID
LOCATIONS AND GRID
NUMBER
RAILROAD
FENCE
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zone and saturated zone are primarily fine- to coarse-grained, poorly sorted sands with some silts and
clays. The alluvial aquifer also contains some poorly sorted gravel zones. The depth to water is about
30 to 40 feet bgs near the CSC warehouse.
Previous soil investigations at the CSC property detected chlorinated VOC contamination extending
from near the surface (less than 5 feet bgs) to the water table depth. The predominant chlorinated
VOCs detected in site soils were PCE, TCE, 1,1,1-TCA, and 1,1-DCA. The area of highest VOC
contamination is north of the CSC tank farm, near the northern railroad spur. The PCE concentrations
detected in this area measure as high as 80 mg/kg, with TCE and 1,1,1-TCA concentrations measuring
as high as 1 mg/kg.
Predemonstration Sampling and Analysis
Predemonstration sampling and analysis were conducted to establish the geographic location of
sampling grids, identify target sampling depths, and estimate the variability of contaminant
concentrations exhibited at each grid location and target sampling depth. Predemonstration sampling
was conducted at the SBA site between April 1 and 11, 1997, and at the CSC site between April 20 and
25, 1997. Eleven sampling grids, six at the SBA site and five at the CSC site, were investigated to
confirm that each grid exhibited chemical concentrations and soil texture characteristics that met the
criteria set forth in the predemonstration sampling plan (PRC, 1997) and to confirm that passive and
active soil gas sampling could be used at the two sites.
At each of the grids sampled during the predemonstration, five borings were advanced and samples
were collected for VOC and soil texture analysis. As expected, the primary VOCs detected in soil
samples at the SBA site were vinyl chloride, cis-l,2-DCE, TCE, and PCE. The primary VOCs
detected at the CSC site were 1,1,1-TCA, TCE, and PCE. TCE and cis-l,2-DCE were detected at the
highest concentrations. Soil texture within each grid was relatively homogeneous at the target GORE-
SORBER® sampling depth of 3 feet.
An active soil gas sampling method sample was collected from an area adjacent to each of the soil
sampling grids at each site. Analysis of samples from these locations confirmed that (1) the active soil
gas sampling method could be used at the two sites, and (2) soil gas contamination was detectable by
the reference method. Of the 11 grids investigated during predemonstration sampling, nine were
selected for demonstration sampling, five grids at the SBA site and four grids at the CSC site.
Demonstration Design
The demonstration was designed to evaluate the GORE-SORBER Screening Survey passive soil gas
sampling system in comparison to the reference sampling method, active soil gas sampling, in terms of
the following parameters: (1) VOC detection and quantitation, (2) sample retrieval time, and (3) cost.
These parameters were assessed in two different soil textures (clay soil at the SBA site and sandy soil at
the CSC site). The demonstration design is described in detail in the demonstration plan (PRC, 1997)
and is summarized below.
Predemonstration sampling identified nine grids (Grids 1, 2, 4, 5, and 6 at the SBA site and Grids 1,2,
4, and 5 at the CSC site) that exhibited consistent soil texture and acceptable VOC concentrations. Each
grid was 10.5 by 10.5 feet in area and was divided into seven rows and seven columns, producing 49,
18- by 18-inch sampling cells (Figure 3-3). Each grid was sampled at a depth of approximately 3
14
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B
D
Ref.
ESP
ESP
Ref.
ESP
Ref.
ESP
Ref.
Ref.
ESP
Ref.
ESP
ESP
Ref.
a
,2
ir
c
•v
1 n c; fnrit
ESP JMC Environmentalist's Subsoil Probe Sampling Location
Ref. Reference Sampling Method Location
Figure 3-3. Typical Sampling Locations and Random Sampling Grid
15
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feet in each of the seven columns (labeled A through G) using the reference soil gas sampling method;
the GORE-SORBER modules were emplaced at a depth of about 3 to 4 inches for passive sampling.
For each grid, seven soil gas samples were collected using the GORE-SORBER modules and reference
soil gas sampling method. The seven cells that were sampled using each method were selected
randomly. The procedure used to collect samples using the GORE-SORBER modules is described in
Chapter 2 and the procedure used to collect samples using the reference soil gas sampling method is
described in Chapter 4.
VOC Detection and Quantitation
After collection of the GORE-SORBER modules, the modules were shipped to the developer for
analysis using a gas chromatography mass spectrometer (GC/MS) according to the developer s standard
operating procedures (Gore, 1996). The reference active soil gas samples were analyzed in an on-site
laboratory following the guidelines discussed in the quality assurance project plan (PRC, 1997). The
guidelines used for on-site analysis were similar to SW-846 Method 5021 (Volatile Organic
Compounds in Soils and Other Solid Matrices Using Equilibrium Headspace Analysis), modified to
include high- and low-concentration procedures similar to those described in SW-846 Method 5035
(Closed-System Purge-and-Trap and Extraction for Volatile Organics in Soil and Waste Samples) (EPA,
1986). The target compounds were vinyl chloride, 1,2-DCE, TCE, and PCE at the SBA site, and 1,2-
DCE, 1,1-DCA, 1,1,1-TCA, TCE, and PCE at the CSC site. Soil gas samples collected from the CSC
site were not analyzed for vinyl chloride because it was not detected in soil during site characterization.
The reference soil gas samples were collected in 40-milliliter (ml) glass volatile organic analysis vials.
The standard injection volume used for soil gas analysis was 2 ml. A gas-tight glass syringe was used
to directly inject the soil gas samples onto the GC column. An electrolytic conductivity detector was
used for compound identification and quantitation. The GC was a Hewlett-Packard Series II equipped
with a packed injection port and a DB-624 column.
Because the GORE-SORBER Screening Survey data were reported as a total mass of analyte absorbed
onto the sample cartridge and the reference soil gas sampling method data were reported as a mass of
analyte detected per liter of air, the data could not be statistically compared directly. Therefore,
graphical methods were used to examine the relationship between the values reported by the two
methods. Mean concentrations from the reference method were plotted on the x axis, and mean analyte
mass values reported by the GORE-SORBER Screening Survey were plotted on the y axis. The
resulting curves were fitted to a trendline that depicts the relationship between the amount of a
compound sorbed and the amount of a compound present in the gas phase. To assess how well the data
set fit the trendline, a correlation coefficient was calculated for each plot.
Sample Retrieval Time
Sample retrieval time was measured as the time required to set up on a sampling grid, install and collect
the seven GORE-SORBER modules from each grid, decontaminate the sampler installation and
collection equipment, and move to a new sampling grid. The time required to install the samplers was
added to the time required to collect the samplers to obtain the sample retrieval time.
16
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Cost
The cost estimate focused on the range of costs for using the GORE-SORBER Screening Survey
passive soil gas sampling system and reference soil gas sampler to collect 40 subsurface soil gas
samples at a clay soil site (similar to the SBA site) and a sandy soil site (similar to the CSC site). The
cost analysis is based on the results and experience gained from the demonstration and cost information
provided by Gore. Factors that could affect the cost of operating the GORE-SORBER Screening
Survey passive soil gas sampling system and the reference soil gas sampler include:
• • Equipment costs
• • Labor costs
• • Sample analysis and reporting costs
• • Decontamination costs
• • Site restoration costs
Deviations from the Demonstration Plan
Three project-wide deviations from the approved demonstration plan were identified: (1) vinyl chloride
was eliminated from the target compound list at the CSC site because vinyl chloride was not detected in
the soil gas at the site; (2) a statistical comparison of the GORE-SORBER Screening Survey data to the
reference data was not performed because the two methods use different sampling techniques and the
data are not directly comparable; and (3) active soil gas sample results were not available from Grid 6
at the SBA site because of laboratory error. Cases where the performance of an individual sampling
technology caused it to deviate from the demonstration plan are discussed on a technology-specific basis
in Chapters 4 (reference method) and 5 (GORE-SORBER Screening Survey) of this ETVR.
17
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Chapter 4
Description and Performance of the Reference Method
This chapter describes the active soil gas sampling system used during the demonstration as the
reference soil gas sampling method, and includes its associated background information, components
and accessories, platform description, demonstration operating procedures, qualitative performance
factors, quantitative performance factors, and data quality measures.
Background
Soil gas screening technology was used as early as 1929 as a surface geochemical technique in oil and
gas exploration. In the early 1980s, active soil gas sampling became widely used as an environmental
investigative tool for aiding in the delineation of subsurface organic contamination. The intent of active
soil gas sampling is to reduce site characterization costs by identifying areas with suspected
contamination, thereby minimizing the number of soil borings and monitoring wells required to
delineate the extent of contamination.
Active soil gas sampling produces a discrete sample that provides a "snapshot" of the soil gas
environment at the time the sample is collected. The sampling technique used in this demonstration
requires the presence of vapor-phase compounds at detectable concentrations, relatively porous
subsurface soil, experienced analytical instrument operators at the site, and portable analytical
equipment for on-site analysis of samples.
Components and Accessories
Two active soil gas sampling systems were used during this demonstration: an AMS™ soil gas
sampling system at the SBA site, and a Geoprobe® soil gas sampling system at the CSC site. The
systems are similar, and this description of system components and accessories applies to both
technologies. The components of the reference sampling method consist of an expendable drive point,
a drive-point holder, drive rods, expendable plastic tubing, a tubing connector, and a vacuum pump.
The 2-inch-long, expendable drive point is a solid steel or aluminum component that has a cone-shaped
drive end and a cylindrical shank on the other end that fits into the point holder. The drive-point
holder is a hollow tube 4 inches long by 1-inch outside diameter. One end of the point holder holds the
expendable point; the other has female threads for attaching the tubing connector. The 2-inch-long,
hollow metal tubing connector has a nipple for the plastic tubing on one end and male threads with a
rubber gasket on the other end, which attaches to the drive-point holder. The 36- to 48-inch-long by
1-inch outside-diameter drive rod is a hollow metal tube with male threads on one end and female
threads on the other. The vacuum pump is capable of drawing a vacuum of 20 to 30 inches of
mercury, is constructed of metal, and has pressure gauges on the sampling line and vacuum tank.
18
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Other components of the reference soil gas sampling system include a drive cap, pull cap, ancillary
tools, and expendable sampling supplies. The drive and pull caps are metal and have female threads on
one end for attaching to the top drive rod. Ancillary tools required include drill bits, vise grips, pipe
wrenches, crescent wrenches, knives, hemostats, and screwdrivers. Expendable sampling supplies
required include the plastic tubing (tygon, Teflon™, or polyethylene), silicone tubing, 40-ml volatile
organic analysis vials, syringe with needle, double-ended needles, and a container for waste.
Because the soil gas samples are usually analyzed immediately, an on-site or nearby laboratory is
typically required. During this demonstration, a GC in an on-site, mobile laboratory was used to
analyze the soil gas samples collected using the reference sampling method.
Description of Platform
The AMS™ and Geoprobe® active soil gas sampling systems use similar platforms to place the
samplers. The platform consists of a hydraulically powered hammer mounted in the bed of a three-
quarter-ton pickup truck. Additional equipment required includes an oil reservoir, a pump, a hammer
support structure, hydraulic control levers, and three hydraulic cylinders: one to fold the hammer for
transport, one to adjust the hammer height, and one to adjust the foot height.
The mobility and performance of the platform were adequate for the conditions at both demonstration
sites. The size of the truck and the ability of the hammer to pivot in multiple directions allowed for
smooth transition from one sampling location to another. The platform easily pushed or hammered the
soil gas samplers to the 4-foot sampling depth at each demonstration site, and the platform easily
extracted the soil gas samplers. The clay soil at the SBA site required less hammering to place the soil
gas samplers than did the sandy soil at the CSC site.
Demonstration Operating Procedures
The reference soil gas sampling method involved assembling and installing the sampling system and
collecting the soil gas sample. Initially, a 1-inch outside-diameter hollow rod was driven to the target
sampling depth within the selected grid cell. The rod was fitted with an expendable drive point. Once
the rod reached the target depth of 4 feet bgs, it was withdrawn approximately 6 inches. The
expendable drive point remained in place, producing a 6-inch void space that allowed a soil gas sample
to be collected. Once the rod was retracted 6 inches, a 0.25-inch inside-diameter, high-density
polyethylene or Teflon™ tube was lowered into the drive rod. The end of the tubing was fitted with a
reverse threaded, barbed fitting. The barb was inserted into the tubing and the reverse threaded end
was screwed into the expendable drive point holder at the end of the drive rod when the tubing reached
the end of the drive rod. A butyl rubber 0-ring around the threaded end of the barb fitting ensured an
airtight seal between the tubing and the end of the drive rod.
Once the tubing was in place, the soil gas sample was collected by attaching an evacuated 40-ml
sampling vial with a double-ended needle to the top end of the system tubing as follows.
1. The sampling vial was evacuated using a 60-cubic-centimeter (cc) plastic syringe. The syringe
pulled a vacuum on the closed sampling vial for 10 seconds. This vacuum was applied by
attempting to draw 60 cc of air out of the vial.
19
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2. A volume-calibrated vacuum system was attached to the end of the polyethylene tube connected
to the end of the hollow rod. The vacuum system removed a volume of air equal to one tubing
volume that was calculated to be 16.4 cc in this demonstration.
3. The vacuum system was shut off and the sampling string was allowed to equilibrate with
ambient air pressure. The system was closed so that equilibration occurred only by drawing
soil gas into the sample tubing. (A vacuum line integrity test was successfully completed before
each sampling event to ensure that there were no leaks in the soil gas system.)
4. When no vacuum was left in the tubing, a double-end hypodermic needle was inserted into the
tygon tubing that connected the polyethylene tubing with the vacuum pump. The exposed end
of the needle was sealed with a soft rubber sheath. The evacuated sampling vial was pushed
onto the exposed needle. The needle penetrated the vial s septum and exposed the soil gas in
the tubing to the vacuum in the vial, causing the vial to fill with soil gas. The sampling vial was
allowed to collect a sample for 40 seconds at the CSC site and 2 minutes at the SBA site. These
times were selected after several tests on refilling evacuated vials were conducted by observing
(1) septa "spring back " to their original positions, and (2) lack of an air hiss upon opening the
vial.
Each sampling vial containing a soil gas sample was numbered according to the sample grid and cell
where it was collected. After the samples were properly labeled, they were analyzed within 24 hours
of collection. Prior to analysis, the active soil gas samples were stored at ambient temperatures.
All reusable soil gas sampling equipment was decontaminated by heating with a portable propane heater
for approximately 30 seconds. The sampling vials and needles were not reused, and the sample tubing
was discarded after a single use.
Qualitative Performance Factors
The following qualitative performance factors were assessed for the reference soil gas sampling
method: (1) reliability and ruggedness under the test conditions, (2) training requirements and ease of
operation, (3) logistical requirements, (4) sample handling, and (5) performance range.
Reliability and Ruggedness
The reliability and ruggedness of the reference active soil gas sampling method was adequate for
conditions at both demonstration sites. The sampler was pushed or hammered to the 4.5-foot sampling
depth at each site without incident. During the demonstration, operators noted that attaching the tubing
adapter to the point holder was easier when the tubing was precut to the required length (per the
sampling depth); otherwise, the tubing tended to unwind when released, which would either loosen or
unscrew the tubing adapter from the point holder. The clay soil at the SBA site caused the system to
hold its vacuum at several sampling locations; hence, soil gas was not completely drawn into the system
for sampling. In these cases, the rod was withdrawn in additional 6-inch increments until the vacuum
was broken and the system s pressure reached equilibrium with atmospheric pressure. The vacuum
problem was not encountered in the sandy soil at the CSC site. The reference soil gas sampling method
operated without any equipment failure or mechanical breakdown during the demonstration.
20
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Training Requirements and Ease of Operation
The active soil gas sampling technology requires minimal training due to the ease of operating the
system. Special certifications, advanced degrees, or other specialized training are not required to
operate the sampling platform and use the system. However, health and safety training is required by
the Occupational Safety and Health Administration when operating at hazardous waste sites. A novice
would require 3 to 6 hours of hands-on training to become proficient at using the sampling platform
and the soil gas sampling system. A two-person crew is recommended for sampling and operation of
the system and platform, but one person may safely operate the system.
Logistical Requirements
Logistical requirements for the reference active soil gas sampling method include obtaining utility
clearances and grouting the sampling holes. Permits to operate the system were not required by the
states of Iowa and Colorado, but may be required in other states. The system, platform, and ancillary
equipment are mounted on or contained in the platform vehicle.
The physical disruption caused by the sampling platform was minimal during the demonstration. No
soil cuttings were generated and a 1-inch diameter hole was left at each sampling location after the
reference soil gas sampling system was extracted. These holes were grouted with bentonite after
samples were collected.
Sample Handling
The reference soil gas samples were easily collected and handled. When no vacuum was left in the
sampling tubing, one end of a double-end hypodermic needle was inserted into the polyethylene tubing
and the other end was inserted through the septum of the evacuated sampling vial. Soil gas in the
tubing was drawn into the sampling vial until the pressure reached equilibrium. This took about 40 to
120 seconds. The sampling vial containing the soil gas sample was numbered according to the sample
grid and cell where it was collected. The soil gas samples were properly labeled and were then stored
at ambient temperature until analysis. The samples were analyzed within 24 hours of collection.
Performance Range
The performance range of the reference soil gas sampling method is limited by soil texture,
permeability, soil moisture content, contaminant type, and depth to groundwater. During the
demonstration, reference soil gas samples were collected from a depth of 4 feet; however, the system is
capable of collecting samples at depths of 30 to 60 feet. Soil such as glacial till with cobbles or fill with
pieces of concrete can cause refusal of the reference sampling method before it reaches the desired
depth. Clay soil may also impede sample collection because the vacuum is not readily released. The
reference soil gas sampling method must be conducted above the water table to avoid drawing water
into the sampling tube.
Quantitative Performance Factors
Three quantitative performance indicators were measured for the reference soil gas sampling method:
(1) VOC detection and quantitation, (2) sample retrieval time, and (3) cost. The following sections
21
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discuss the first two performance factors; a cost analysis of the reference soil gas sampling method is
provided in Chapter 6.
VOC Detection and Quantitation
Seven samples were collected using the reference soil gas sampling method within each grid as
described in Chapter 3 and specified in the demonstration plan (PRC, 1997). Samples were analyzed
for VOCs by GC analysis according to the standard operating guideline provided in the demonstration
plan (PRC, 1997). Table 4-1 presents the range and mean VOC concentrations for samples collected
using the reference method. The VOC results for each sample collected are presented in Appendix A.
For Grid 6 at the SB A site, VOC data for the reference method were not available because of
laboratory error. For one of the sampling grids, VOC data for all seven samples are not available due
to laboratory error; in this case, the range and mean were calculated from the available data. Chapter 5
presents a graphical comparison of the analytical results obtained using the reference soil gas sampling
method to those obtained using the GORE-SORBER Screening Survey.
Sample Retrieval Time
The reference soil gas method required 458 minutes to collect 35 samples at the SB A site, an average of
13.1 minutes per sample, and 183 minutes to collect 28 samples at the CSC site, an average of 6.5
minutes per sample. Sample retrieval time was measured as the amount of time per sample required to
set up at a sampling grid, collect the required samples, grout the hole, decontaminate the sampling
equipment, and move to a new sampling location. Analytical results were available from the on-site
laboratory within one day; this time was not included in calculating the sample retrieval time. A three-
person sampling and analysis crew collected and analyzed soil gas samples using the reference soil gas
sampling method at both sites. The difference in sample retrieval time between the SBA and CSC sites
may be due in part to differences in soil type (clay versus sandy soil).
Data Quality
Data quality was assessed throughout this demonstration by implementing an approved quality
assurance project plan (PRC, 1997). The QA/QC procedures included the consistent application of
approved methods for sample collection, chemical analysis, and data reduction. Based on the intended
use of the data, QA objectives for precision, accuracy, representativeness, comparability, and
completeness were established, and QC samples were collected to assess whether the QA objectives
were met. Based on the results of a field audit conducted by the EPA and a detailed validation of the
demonstration data by Tetra Tech, the data have been deemed acceptable for use as described in the
demonstration design (Chapter 3). The results of the QC indicators used for the reference soil gas
sampling method are provided in the technology evaluation report for this demonstration (Tetra Tech,
1997) and are summarized below.
All reference soil gas samples were analyzed within 24 hours of collection, as specified in the quality
assurance project plan. Some initial calibrations of the Hewlett-Packard Series II GC had to be
abbreviated to meet acceptance criteria, and either a five-point or a three-point calibration was utilized
instead of the specified six-point calibration. However, all continuing calibrations met the acceptance
criteria for percent difference, indicating that the calibration was reproducible. Two method blanks
were analyzed at the SBA site and one at the CSC site. In addition, one ambient air blank and one
22
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Table 4-1. Volatile Organic Compound Concentrations in Samples Collected Using the Reference Soil Gas Sampling Method
Concentration (ng/L)
Site Grid
SBA 1
SBA 2
SBA 4
SBA 5
SBA 6 *
CSC 1
CSC 2
CSC 4
CSC 5 f
Vinyl Chloride
Range Mean
230,000- 2,390,000
5,180,000
<100 <100
<100 <100
<100- 1,980
8,270
NA NA
NA NA
NA NA
NA NA
NA NA
Total DCE
Range Mean
279,000- 958,000
2,220,000
<50- 151 65
< 50 -261 101
3,180- 9,980
21,000
NA NA
2,260- 10,800
21,300
<500- 1,850
3,780
<500- 6,190
10,500
< 500 - 738
1,400
1,1 DCA
Range Mean
<50 <50
<50 <50
<50 <50
<50 <50
NA NA
<500 <500
<500 <500
<500 <500
<500 <500
1,1,1-TCA
Range Mean
<50 <50
<50 <50
<50 <50
<50 <50
NA NA
7,530- 314,000
670,000
33,900- 288,000
439,000
19,600- 142,000
217,000
12,600- 69,900
132,000
TCE
Range Mean
<50 <50
183-5,380 1,250
744-33,600 9,390
132-6,250 2,010
NA NA
7,450- 41,800
77,400
11,400- 89,500
154,000
1,880- 22,200
41,800
2,430- 11,500
24,700
PCE
Range Mean
<50 <50
<50 <50
<50 <50
<50 <50
NA NA
79,000- 330,000
770,000
32,000- 223,000
427,000
20,800- 192,000
389,000
24,800- 98,500
220,000
ng/L Nanograms per liter
Total DCE Total Dichloroethene
1,1,1-TCA 1,1,1 -Trichloroethane
CSC Chemical Sales Company site
t VOC data for only five samples are available
* VOC data are not available because of
laboratory error
1,1 -DCA 1,1 -Dichloroethane
PCE Tetrachloroethene
TCE Trichloroethene
SBA Small Business Administration site
NA Not analyzed
23
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equipment blank were analyzed at each site. None of these blanks exhibited any target compounds
above the quantitation limit, indicating that there were no apparent sample contamination problems at
either site.
Tetra Tech performed a data validation review of all data, and an EPA Region 8 QC chemist performed
an audit of the laboratory during the predemonstration phase. Neither of these reviews noted any
significant data quality issues. Thus, the data appear to be of sufficient quality for the intended use.
24
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Chapter 5
Technology Performance
This chapter describes the performance of the GORE-SORBER Screening Survey passive soil gas
sampling system in terms of qualitative and quantitative performance factors. A description of the
GORE-SORBER Screening Survey is provided in Chapter 2.
Qualitative Performance Factors
The following qualitative performance factors were assessed for the GORE-SORBER Screening
Survey: (1) reliability and ruggedness under the test conditions, (2) training requirements and ease of
operation, (3) logistical requirements, (4) sample handling, and (5) performance range.
Reliability and Ruggedness
The GORE-SORBER Screening Survey collected 100 percent (63 of 63) of the samples without
sample loss or downtime, which verifies the developer claim that the samplers can collect soil gas
samples in clay and poorly drained soils. The GORE-SORBER® modules are protected during shipping
by placing them in 2-ounce jars inside foam packaging. This procedure minimizes any possible damage
to the sorbers during shipping.
Training Requirements and Ease of Operation
The GORE-SORBER modules were installed by the developer, but the developer claims that no
specialized training is required. When deemed desirable or necessary by a client, the developer
furnishes a 10-minute training video.
Logistical Requirements
No special license requirements are necessary to use the GORE-SORBER Screening Survey. The
system requires two mobilizations: one trip is required to install the samplers, and a second trip is
needed to collect the samplers. Once the samples are collected, they must be returned to the developer
for analysis.
Installation of the GORE-SORBER module requires drilling a 0.5-inch to 0.75-inch hole between 2
and 3 feet deep. Shallow underground utilities such as cable, telephone, and electrical lines should be
located and utility clearances should be obtained before the holes are drilled. Installation of samples
through paved surfaces requires the use of a roto-hammer or drill, and holes in the pavement are
usually patched after sampling. The roto-hammer requires an electrical power source.
25
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For this demonstration push platforms mounted on pickup trucks were used to create the pilot holes for
the GORE-SORBER modules. The physical impact of demonstration sampling on the site was
minimal. The GORE-SORBER modules left 0.75-inch-diameter holes in the ground surface, which
were grouted with bentonite after the samplers were collected.
Sample Handling
GORE-SORBER module retrieval requires that field personnel locate the sampler, remove the cork
used to seal the annulus of the installation hole, grasp the retrieval cord, and manually pull the sampler
from each location. Corks are separated from the module and discarded. The exposed samplers are
resealed in the designated shipping jars and placed immediately on ice in coolers supplied by the
technology developer. Coolers are returned to the developer under proper chain-of-custody
documentation. The GORE-SORBER modules are then analyzed in the developer s analytical
laboratory using a GC/MS.
Performance Range
GORE-SORBER® modules use granular adsorbents housed in a chemically inert, hydrophobic,
microporous GORE-TEX® ePTFE membrane. Gore claims that the unique properties of the ePTFE
membrane protect the granular adsorbents from physical contact with soil particulates and water,
thereby allowing the GORE-SORBER® module to be placed directly in soil either in the vadose or
saturated zones. Typical sampling depths for the GORE-SORBER® module are between 2 and 5 feet.
The sampling depth used during the demonstration was 3 feet.
Quantitative Performance Assessment
Quantitative measures of the performance of the GORE-SORBER® Screening Survey passive soil gas
sampling system consisted of (1) VOC detection and quantitation, (2) sample retrieval time, and
(3) cost. The following sections discuss the first two performance factors; a cost analysis of the GORE-
SORBER® Screening Survey is provided in Chapter 6.
VOC Detection and Quantitation
Seven samples were collected using the GORE-SORBER® modules within each sampling grid, as
described in Chapter 3. Samples were analyzed for VOCs by GC/MS according to the standard
operating guideline provided in the demonstration plan (PRC, 1997). Table 5-1 presents the range and
mean VOC mass calculated from samples collected using the GORE-SORBER® Screening Survey. The
VOC results for each sample collected are presented in Appendix A.
Table 5-2 compares the mean VOC concentrations detected using the GORE-SORBER Screening
Survey to those detected in the samples collected using the reference method. In all cases, the GORE-
SORBER Screening Survey detected the same compounds in each grid as the reference method, and in
several instances detected compounds that were not detected using the reference method. For example,
the GORE-SORBER Screening Survey detected low levels of PCE at the SBA site and low levels of
1,1-DCA at the CSC site, where the reference method did not detect these compounds. Past soil
sampling at the sites confirmed the presence of these contaminants.
26
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Table 5-1. Volatile Organic Compound Mass in Samples Collected Using the GORE-SORBER Screening Survey
Mass G"g/sample)
Site Grid
SBA 1
SBA 2 .
SBA 4
SBA 5
SBA 6
CSC 1
CSC 2
CSC 4
CSC 5
Vinyl Chloride
Range Mean
399-1,640 919
<1.77 <1.77
<1.77 <1.77
< 1.77 -3. 62 2.77
<1.77 <1.77
NA NA
NA NA
NA NA
NA NA
Total DCE
Range Mean
507 - 665 592
0.76 - 14.6 6.04
0.84-3.21 1.38
16.2-119 59.7
<0. 02 -0.81 0.18
96.0 - 242 181
80.9-115 95.2
155-217 189
40.3 - 88.9 65.0
1,1-DCA
Range Mean
<0.01 <0.01
<0.01 <0.01
<0.01 <0.01
<0.01 <0.01
<0.01 <0.01
<0.01-0.16 0.08
<0.01 <0.01
<0. 01 -0.13 0.06
<0.01 <0.01
1,1,1-TCA
Range Mean
<0.02 <0.02
<0.02 <0.02
<0.02 <0.02
<0.02 <0.02
<0.02 <0.02
28.4 - 50.3 38.3
31.9-43.8 37.6
24.4 - 35.3 30.2
16.7 - 25.5 22.3
TCE
Range Mean
0.70-4.11 1.97
69.9 - 163 108
51.6-327 195
8.90-75.5 34.8
<0.02 <0.02
208 - 287 255
296-335 318
209 - 273 252
189 - 239 217
PCE
Range Mean
0.02-0.14 0.06
0.54-1.58 1.02
0.08-1.08 0.42
0.03-0.14 0.08
<0.03 <0.03
397-433 411
307 - 367 341
324 - 367 351
292 - 345 327
Mg/sample Micrograms per sample PCE Tetrachloroethene
Total DCE Total Dichloroethene TCE Trichloroethene
1,1-DCA 1,1-Dichloroethane NA Not analyzed
1,1,1-TCA 1,1,1-Trichloroethane SBA Small Business Administration site
CSC Chemical Sales Company site
to
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Table 5-2. Mean Chemical Concentrations of the GORE-SORBER® Screening Survey and Reference Soil Gas Sampling Method
Mean Concentration
Site Grid
SBA 1
SBA 2
SBA 4
SBA 5
SBA 6
CSC 1
CSC 2
CSC 4
CSC 5
Vinyl Chloride
GORE- Ref.
SORBER® (ng/L)
(Mg/sample)
919 2,390,000
<1.77 <100
<1.77 <100
2.77 1,980
<1.77 NA
NA NA
NA NA
NA NA
NA NA
Total DCE
GORE- Ref.
SORBER* (ng/L)
(Aig/sample)
592 958,000
6.04 65
1.38 101
59.7 9,980
0.18 NA
181 10,800
95.2 1,850
189 6,190
65.0 738
1,1-DCA
GORE- Ref.
SORBER® (ng/L)
(Aig/sample)
<0.01 <50
<0.01 <50
<0.01 <50
<0.01 <50
<0.01 NA
0.08 <500
<0.01 <500
0.06 <500
<0.01 <500
1,1,1-TCA
GORE- Ref.
SORBER® (ng/L)
(/jg/sample)
<0.02 <50
<0.02 <50
<0.02 <50
<0.02 <50
<0.02 NA
38.3 314,000
37.6 288,000
30.2 142,000
22.3 69,900
TCE
GORE- Ref.
SORBER® (ng/L)
(^g/sample)
1.97 <50
108 1,250
195 9,390
34.8 2,010
<0.02 NA
255 41,800
318 89,500
252 22,200
217 11,500
PCE
GORE- Ref.
SORBER* (ng/L)
(/^g/sample)
0.06 <50
1.02 <50
0.42 <50
0.08 <50
<0.03 NA
411 330,000
341 223,000
351 192,000
327 98,500
^g/sample Micrograms per sample NA Not analyzed
ng/L Nanograms per liter PCE Tetrachloroethene
Total DCE Total Dichloroethene TCE Trichloroethene
1,1-DCA 1,1-Dichloroethane Ref. Reference Soil Gas Sampling Method
1,1,1-TCA 1,1,1-Trichloroethane SBA Small Business Administration site
CSC Chemical Sales Company site
N)
CO
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The ability of the GORE-SORBER Screening Survey to detect low-concentration VOCs that the
reference sampling method did not detect suggests that, under conditions similar to this demonstration,
the prolonged sampling period for the GORE-SORBER modules may provide higher sensitivity to
low-concentration contaminants.
The GORE-SORBER Screening Survey and the reference method are field screening techniques that
provide only an estimate of the actual concentration of contaminants in the soil gas. Because the
GORE-SORBER Screening Survey and the reference method use different methods to collect soil gas
samples, it is not expected that the two methods will provide the same response. Furthermore, because
analysis of GORE-SORBER modules yields results in micrograms per sample and the reference
method produces results in nanograms per liter, the data cannot be directly compared. Consequently,
graphical methods were used to examine the relationship between the values reported by the two
methods. Comparative plots for total DCE, 1,1,1-TCA, TCE, and PCE data are presented as Figures
5-1 through 5-4. Mean concentrations from the reference method are plotted on the x axis, and mean
analyte mass values reported by the GORE-SORBER Screening Survey are plotted on the y axis.
Insufficient data are available to provide a meaningful plot of vinyl chloride and 1,1-DCA data. [Note:
Neither the GORE-SORBER Screening Survey or the reference sampling method detected 1,1-DCA or
1,1,1-TCA at the SBA site, which also correlates with analytical data from soil and groundwater
collected at the site by E&E and predemonstration activities conducted by Tetra Tech.]
Based on a review of the data distribution presented in Figures 5-1 through 5-4, the relationship
between the mass of compounds measured on the GORE-SORBER modules and the concentrations
measured using the reference sampling method is nonlinear, and suggests a logarithmic trend.
Logarithmic trendlines were fitted to each plot, and a correlation coefficient was calculated to evaluate
how well the trendlines matched the data. The correlation coefficients were 0.815 for total DCE, 0.997
for 1,1,1-TCA, 0.876 for TCE, and 0.994 for PCE. A correlation factor of 1.00 is a "perfect" match
with the logarithmic trendline.
The plots indicate that there is a relative correlation between the GORE-SORBER Screening Survey
and reference method data; the higher the concentration of contaminant in the soil gas, the higher the
mass detected using the GORE-SORBER Screening Survey. The plots also show that at higher
contaminant levels, the ratio between the mass of contaminant detected using the GORE-SORBER
modules and the concentration of contaminant in the soil gas decreases, suggesting sorbent saturation
may have occurred in the GORE-SORBER modules.
Sample Retrieval Time
During the demonstration, installation of the GORE-SORBER modules averaged 8.0 minutes per
sampler at the SBA site and 7.4 minutes per sampler at the CSC site. For the demonstration, the
samplers were left in place for approximately 10 days at each site. Collection of the samplers required
an average of 1.9 minutes per sampler at the SBA site and 2.4 minutes at the CSC site. Overall,
installation and collection of 35 GORE-SORBER modules at the SBA site required 346 minutes, an
average of 9.9 minutes per sample and installation and collection of 28 GORE-SORBER modules at
the CSC site required 274 minutes, an average of 9.8 minutes per sample. The analysis and reporting
by the technology developer required 14 to 18 days from the time samples were collected until the
laboratory report was delivered. The sample retrieval time included the amount of time per sample
required to set up at a sampling grid, install and collect the seven samplers, grout the hole,
29
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700
•
R2
Total DCE
Correlation
Coefficient
• i otal JJUt
Trendline
200,000 400,000 600,000 800,000 1,000,00 1,200,00
0 0
Concentration (Nanograms per Liter)
Reference Method
Figure 5-1. Comparative Plot of Mean Total DCE Mass Versus Concentratioi
100 -1
90
-SORBER® Module
Sample (Micrograms)
-N en en ^J oo
o o o o o
K 1, 30-
8j 20
10
n
•^
^~+
,
•-
— *
• 1,1,1-TCA
R2 Correlation
Coefficient
111 TP \
Trendline
R2 = 0.997
I
50,000 100,000 150,000 200,000 250,000 300,000 350,000
Concentration (Nanograms per Liter)
Reference Method
Figure 5-2. Comparative Plot of Mean 1,1,1-TCA Mass Versus Concentratio
30
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350 T
FT = 0.876
20,000 40,000 60,000 80,000 100,000
A TCE
R2 Correlation
Coefficient
TCE Trendline
Concentration (Nanograms per Liter)
Reference Method
Figure 5-3. Comparative Plot of Mean TCE Mass Versus Concentratioi
g b 15°
8 1 100
50,000 100,000 150,000 200,000 250,000 300,000 350,000
Concentration (Nanograms per Liter)
Reference Method
Figure 5-4. Comparative Plot of Mean PCE Mass Versus Concentratioi
31
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decontaminate the sampling equipment, and move to a new sampling location. A two-person sampling
crew installed and collected the GORE-SORBER Screening Survey samples at both sites.
Table 5-3 presents a comparison of the average sample retrieval times for the GORE-SORBER
modules and those for the reference soil gas sampling method. The average sample retrieval times for
the GORE-SORBER modules were quicker than the reference sampling method in the clay soils at the
SBA site and slower than the reference sampling method in the sandy soils at the CSC site.
Table 5-3. Average Sample Retrieval Times for the GORE-SORBER® Modules and the
Reference Soil Gas Sampling Method
Average Time
(minutes per sample)
Sampler
SBA Site CSC Site
GORE-SORBER® Module
Average Sample Installation Time
Average Sample Collection Time
8.0
1.9
7.4
2.4
Average Sample Retrieval Time 9.9
Reference Sampling Method
Average Sample Retrieval Time 13.1 6.5
Note: A two-person sampling crew installed and collected soil gas samples using the GORE-SORBER
Screening Survey at both the SBA and CSC sites, and a three-person sampling and analysis crew collected
and analyzed the soil gas samples using the reference soil gas sampling method at both sites.
Data Quality
Data quality was assessed throughout this demonstration by implementing an approved quality
assurance project plan (PRC, 1997). The QA/QC procedures included the consistent application of
approved methods for sample collection, chemical analysis, and data reduction. Based on the intended
use of the data, QA objectives for precision, accuracy, representativeness, comparability, and
completeness were established and QC samples were collected to assess whether the QA objectives were
met. Based on the results of a field audit conducted by EPA and a detailed validation of the data by
Tetra Tech, the data have been deemed acceptable for use as described in the demonstration design
(Chapter 3). The results of the QC indicators used for this demonstration for the GORE-SORBER
Screening Survey are provided in the technology evaluation report for this demonstration (Tetra Tech,
1997) and are summarized below.
As planned, adsorbent samples from the SBA site were sent to the developer for analysis in accordance
with the developer s standard operating procedures. The developer applied its own standard quality
control procedures, as described in detail in the developer s data report provided in the technology
evaluation report for this demonstration (Tetra Tech, 1997). The QC samples included field blanks,
trip blanks, and laboratory duplicates.
32
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At the SB A site, the target chlorinated hydrocarbon VOCs were not detected in the field blank. Cis-
1,2-dichloroethene was detected up to 0.30 • g per sample in the three trip blanks; however, this was
on the order of 1 percent of the average amount of cis-l,2-dichloroethene in samples. At the CSC site,
minor PCE contamination (up to 0.43 • g per sample) was observed in the field blank and the three trip
blanks. Lower levels of contamination with TCE and 1,1,1-TCA were also observed in the three trip
blanks. These contamination levels were low in comparison to the sample concentrations (mean PCE
concentration was 345 • g per sample). Therefore, potential contamination of samples did not appear to
be a significant issue at either site and the resulting data quality impacts are considered minimal.
The results of analysis of nine laboratory duplicate samples indicated that precision, as measured by the
relative percent difference (RPD) of the duplicate results, was consistently within the QA objective of
50 percent for all target analytes. Only one result was outside the 50 percent objective (the RPD for
PCE from the SBA site was 64 percent). Thus, method precision also appears to be acceptable.
33
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Chapter 6
Economic Analysis
The GORE-SORBER Screening Survey passive soil gas sampling system was demonstrated at two sites
that varied geologically and were contaminated with VOCs at a range of concentrations. This chapter
presents an economic analysis for applying the GORE-SORBER Screening Survey at sites similar to
those used in this demonstration. The demonstration costs for the reference sampling method are also
provided.
This economic analysis estimates the range of costs for using a GORE-SORBER Screening Survey to
collect 40 subsurface soil gas samples at a clay soil site (similar to the SBA site) and a sandy soil site
(similar to the CSC site). The analysis is based on the results and experience gained from this
demonstration and on costs provided by Gore. To account for variability in cost data and assumptions,
the economic analysis is presented as a list of cost elements and a range of costs for collecting soil gas
samples using the GORE-SORBER Screening Survey and reference sampling method.
Assumptions
Several factors affect the cost of subsurface soil gas sampling. Wherever possible, these factors are
identified so that decision makers can independently complete a site-specific economic analysis. For
example, this cost estimate is based on the soil type and average sample retrieval times calculated during
the demonstrations at the SBA and CSC sites. This cost estimate assumes that a hammer-driven, steel
rod is used to install the GORE-SORBER Screening Survey 3 feet bgs, and that a direct-push platform
is used to advance the active soil gas sampling system to a depth of 4.5 feet bgs for sample collection.
The cost estimate also assumes that a one-person sampling crew collects soil gas samples using the
GORE-SORBER Screening Survey and that a two-person sampling and analysis crew collects and
analyzes soil gas samples using the reference sampling method.
GORE-SORBER® Screening Survey
The costs for collecting soil gas samples using the GORE-SORBER Screening Survey are presented in
two categories: (1) sampler, sample analysis, and equipment costs, which include mobilization/
demobilization, equipment use, and sampler and sample analysis for the GORE-SORBER Screening
Survey and (2) operating costs, which include labor for sampler installation and retrieval and other
direct costs such as supplies and site restoration.
The cost categories and associated cost elements are defined and discussed below and serve as the basis
for the estimated cost ranges presented in Table 6-1.
34
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t®
Table 6-1. Estimated Subsurface Soil Gas Sampling Costs for the GORE-SORBER Screening
Survey
Sampler, Sample Analysis, and Equipment Costs
Mobilization/Demobilization = $200 to $600 per site
Equipment = $25 to $85 per day
GORE-SORBER® Module and Sample Analysis = $125 to $225 per sample
Operating Costs
Clay Soil Site
Sample Retrieval Time = 7 to 9 hours (1 day)
Total Samples Collected = 40
Total Sample Depth =120 feet (3 feet/sample)
Sampling Crew Size = 1 Person
Sandy Soil Site
Sample Retrieval Time = 7 to 9 hours (1 day)
Total Samples Collected = 40
Total Sample Depth =120 feet (3 feet/sample)
Sampling Crew Size = 1 Person
Labor Costs
Mobilization/Demobilization
Travel
Per Diem
Sample Retrieval
Other Direct Costs
Supplies
Site Restoration
Range of Operating Costs*
$400 - $600
$12-$60
0 - $300
$350 - $450
$25-$75
$25-$50
$810-$1,540
Labor Costs
Mobilization/Demobilization
Travel
Per Diem
Sample Retrieval
Other Direct Costs
Supplies
Site Restoration
$400 - $600
$12-$60
0 - $300
$350 - $450
$25-$75
$25-$50
$810-$1,540
* The range of Operating Costs is rounded to the nearest tens of dollars and does not include Sampler, Sample
Analysis, and Equipment Costs
Sampler, Sample Analysis, and Equipment Costs. These costs include mobilization/demobilization,
equipment, and sampler and sample analysis for the GORE-SORBER Screening Survey. Cost ranges
were estimated as a daily equipment use fee and a per-sample charge. The costs include:
• Mobilization/Demobilization Costs — These costs include preparing, delivering, and setting up
the sampling equipment as well as packing up and returning the equipment to the vendor s
facility. Equipment mobilization and demobilization costs are estimated to range from $200 to
$600 for each site.
• Equipment Costs — Based on the average sample retrieval times for the demonstration and on
collecting 40 samples at each site, it is assumed that 1 day will be required to install the passive
soil gas detectors at the clay soil site and 1 day at the sandy soil site. Equipment costs are
estimated to range from $25 to $85 per day and include the cost of equipment to install the
passive soil gas sampler (hammer-driven steel rod [$25 per day]) and rental of a roto-hammer
($60 per day). A roto-hammer is required only if samplers must be installed below pavement.
No equipment is needed during retrieval of the passive soil gas detectors.
35
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• GORE-SORBER® Module and Sample Analysis Costs — Unit costs of the GORE-SORBER®
Screening Survey include GORE-SORBER modules, laboratory analysis, data tables, maps,
and a final report. The GORE-SORBER Screening Survey costs range from $125 to $225 per
sample, depending on the selected target analytes. The GORE-SORBER Screening Survey
costs include off-site laboratory analysis using a GC/MS.
Operating Costs. Operating costs are limited to mobilization/demobilization, travel, on-site labor costs,
and per diem. Operating costs for collecting the GORE-SORBER modules are segregated into labor
costs and other direct costs, as shown below.
Labor costs include mobilization/demobilization, travel, per diem, and sample retrieval costs.
• Mobilization/Demobilization Labor Costs — This cost element includes the time for one person
to prepare for and travel to each site and includes 4 to 6 hours at a rate of $50 per hour for two
trips (one for sampler installation and one for sampler collection).
• Travel Costs — Travel costs for each site are limited to round-trip mileage costs and are
estimated to be between 20 to 100 miles at a rate of $0.30 per mile for 2 trips (one for sampler
installation and one for sampler collection).
• Per Diem Costs — This cost element includes food, lodging, and incidental expenses and is
estimated to range from zero (for a local site) to $150 per day per person for one person for 2
days (1 day for mobilization and sample installation; 1 day for sample collection,
demobilization, and site restoration.) Costs are estimated to be the same for the clay site and the
sandy site.
• Sample Retrieval Labor Costs — On-site labor costs include labor for sampler installation and
sampler collection. Because installation and collection of the GORE-SORBER modules is
relatively simple, additional oversight labor is not required. Only one person is required to
install and collect the passive soil gas detectors. Based on the average demonstration sample
retrieval times, sample installation and collection labor times are estimated to be 7 to 9 hours for
one person at each site (clay or sandy soil). Labor rates are estimated at $50 per hour.
Other direct costs include supplies and site restoration costs.
• Supplies — This cost element includes decontamination supplies, such as buckets, soap, high-
purity rinse water, and brushes, as well as personal protective equipment (Level D, the
minimum level of protection, is assumed). Supplies are estimated to cost between $25 and $75.
• Site Restoration — Site restoration costs include grouting the sample boreholes and site
restoration labor. Grouting costs for each site are limited to grout and grouting tools ($25 to
$50). Site restoration labor cost are included under sample retrieval labor costs.
Reference Sampling Method
The costs for implementing the reference soil gas sampling method (active soil gas sampler) during the
demonstration include categories for sampling and analysis and for oversight, as presented in Table 6-2
and discussed below.
36
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Table 6-2. Estimated Subsurface Soil Gas Sampling Costs for the Reference Sampling Method
Sampling and Analysis Equipment Costs
Lump Sum = $4,700 for each site
Oversight Costs
Clay Soil Site
Total Sampling Time = 9 to 11 hours (2 days)
Total Samples Collected = 40
Total Sample Depth = 180 feet (4.5 feet/sample)
Sampling Crew Size = 2 People
Sandy Soil Site
Total Sampling Time = 5 to 7 hours (1 day)
Total Samples Collected = 40
Total Sample Depth = 180 feet (4.5 feet/sample)
Sampling Crew Size = 2 People
Labor Costs
Mobilization/Demobilization
Travel
Per Diem
Sampling Oversight
Other Direct Costs
Supplies
Range of Oversight Costs*
$200 - $300
$6 - $30
0 - $300
$450-$550
$25-$75
$680-$1,260
Labor Costs
Mobilization/Demobilization
Travel
Per Diem
Sampling Oversight
Other Direct Costs
Supplies
$200 - $300
$6 - $30
0-$150
$250-$350
$25-$75
$480 - $910
* The range of Oversight Costs is rounded to the nearest tens of dollars and does not include Sampling and
Analysis Equipment Costs
Sampling and Analysis Costs. Total lump sum sampling and analysis equipment costs for the clay and
sandy soil sites was $4,700 for each site, and included:
• Mobilization and demobilization
• Drilling footage
• Active soil gas sampling system
• On-site laboratory analysis using a GC and electrolytic conductivity detector
• Active soil gas sampling and analysis crew labor costs (2 people)
• Per diem for the crew (2 people)
• Grouting boreholes
• Site restoration
• Decontamination supplies
• Waste collection and containerization
• Data tables
Additional mobilization/demobilization and per diem costs will apply if the site is more than 100 miles
from the active soil gas developer. The minimum active soil gas sampling cost is $2,500 per day for
the collection and analysis of 20 samples for six or fewer VOCs. Up to 20 additional samples could be
collected per day at an additional cost of $90 per sample and $5 per linear sample depth foot.
37
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Oversight Costs. Oversight costs are presented as ranges to provide an estimate of oversight costs that
may be incurred at other sites. Costs for overseeing the reference sampling are segregated into labor
costs and other direct costs, as shown below.
Labor costs include mobilization/demobilization, travel, per diem, and sampling oversight.
• Mobilization/Demobilization Labor Costs — This cost element includes the time for one person to
prepare for and travel to each site, and includes 4 to 6 hours each at a rate of $50 per hour.
• Travel Costs — Travel costs for each site are limited to round-trip mileage costs for 20 to 100
miles at a rate of $0.30 per mile.
• Per Diem Costs — This cost element includes food, lodging, and incidental expenses and is
estimated to range from zero (for a local site) to $150 per day for one person for 2 days at the
clay soil site (1 day for sample collection and '/; day for mobilization and demobilization and
site restoration) and for one person for 1 day at the sandy soil site ('/! day for sample collection
and '/! day for mobilization/demobilization and site restoration). No per diem costs are
presented for the sampling and analysis crew because these costs are included in the sampling
and analysis equipment lump sum.
• Sampling Oversight Labor Costs — On-site labor, often a registered geologist, is required to
oversee sample collection. Active soil gas collection labor typically includes a platform operator
and one helper to collect samples and decontaminate sampling equipment. Therefore, the total
number of personnel on site would be three: one person to oversee sampling activities and two
people to operate the direct-push equipment and collect samples. Based on the average sample
retrieval times determined during the demonstration, sampling oversight labor times are
estimated to be 9 to 11 hours for one person at the clay soil site and 5 to 7 hours for one
person at the sandy soil site. Labor rates are assumed to be $50 per hour. Labor costs for the
active soil gas sampler operators are included in the equipment costs.
Other direct costs include supplies. Decontamination and site restoration costs are included under the
sampling and analysis equipment costs.
• Supplies — This cost element includes personal protective equipment (Level D, the minimum
level of protection, is assumed) and other miscellaneous field supplies. Supplies are estimated
to cost between $25 and $75.
38
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Chapter 7
Summary of Demonstration Results
This chapter summarizes the technology performance results. The GORE-SORBER Screening Survey
was compared to the reference method (active soil gas sampling) in terms of the following parameters:
(1) VOC detection and quantitation, (2) sample retrieval time, and (3) cost. The demonstration data
indicate the following performance characteristics for the GORE-SORBER Screening Survey:
• VOC Detection and Quantitation: The GORE-SORBER® Screening Survey detected the same
compounds in each sample as the reference soil gas sampling method, as well as several VOCs
that the reference method did not detect. This performance characteristic suggests that the
GORE-SORBER Screening Survey may detect VOCs that are at lower concentrations in the
subsurface than the reference soil gas sampling method can detect. The results also indicate a
general correlation between the GORE-SORBER Screening Survey and reference method data.
However, at high contaminant levels, the ratio between the mass of contaminant in soil gas
detected using the GORE-SORBER module and the concentration of contaminant in soil gas
detected using the reference soil gas sampling method decreases, suggesting that sorbent
saturation may have occurred. The GORE-SORBER Screening Survey and reference method
are field screening techniques that provide only an estimate of the actual concentration of
contaminants in soil gas. Because the GORE-SORBER Screening Survey and reference
method use different techniques to collect soil gas samples, it is not expected that the two
methods will provide the same response or that the data will be directly comparable. In
addition, the GORE-SORBER Screening Survey yields results in micrograms per sample and
the reference soil gas sampling method reports results in nanograms per liter. Therefore, a
statistical analysis of the data was not performed, and interpretation of the chemical
concentration data for this demonstration is limited to qualitative observations.
• Sample Retrieval Time: Installation of the GORE-SORBER® modules averaged 8.0 minutes
per sampler at the SBA site and 7.4 minutes per sampler at the CSC site. For the
demonstration, the modules were left in place for approximately 10 days. Collection of the
modules required an average of 1.9 minutes per sampler at the SBA site and 2.4 minutes at the
CSC site. Overall, installation and collection of 35 GORE-SORBER® modules at the SBA site
required 346 minutes, an average of 9.9 minutes per sample and installation and collection of
28 GORE-SORBER modules at the CSC site required 274 minutes, an average of 9.8 minutes
per sample. The analysis and reporting by the technology developer required 14 to 18 days
from the time samples were collected until the laboratory report was delivered. The reference
soil gas method required 458 minutes to collect 35 samples at the SBA site, an average of 13.1
minutes per sample, and 183 minutes to collect 28 samples at the CSC site, an average of 6.5
minutes per sample. One day was required per site to analyze the samples and report the
results. Based on the demonstration results, the average sample retrieval times for the GORE-
39
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SORBER modules were quicker than the reference method in the clay soils at the SBA site and
slower than the reference sampling method in the sandy soils at the CSC site. The results also
indicate that the sample retrieval time for the GORE-SORBER modules may be less susceptible
to variations in soil type than the sample collection times for the reference method. During
sample collection using the reference method, the clay soil at the SBA site caused the system to
hold its vacuum at several sampling locations; therefore, soil gas was not completely drawn into
the system for sampling. In these cases, the rod was withdrawn in additional 6-inch increments
until the vacuum was broken and the system s pressure reached equilibrium with atmospheric
pressure. The vacuum problem was not encountered in the sandy soil at the CSC site. A two-
person sampling crew retrieved soil gas samples using the GORE-SORBER Screening Survey
at both the SBA and CSC sites, and a three-person sampling and analysis crew collected and
analyzed soil gas samples using the reference method at both sites.
• Cost: Based on the demonstration results, the GORE-SORBER Screening Survey cost $125 to
$225 per sample plus equipment costs of $25 to $85 per day and mobilization/demobilization
costs of $200 to $600 per site. Operating costs for the GORE-SORBER Screening Survey
ranged from $810 to $1,540 at both the clay soil site and the sandy soil site. For this
demonstration, the active soil gas sampling method was procured at a lump sum of $4,700 per
site for the collection and analysis of 40 soil gas samples at each site. Oversight costs for the
active soil gas sampling method ranged from $680 to $1,260 at the clay soil site and $480 to
$910 at the sandy soil site. A site-specific cost and performance analysis is recommended
before selecting a subsurface soil gas sampling method.
In general, the data quality indicators selected for this demonstration met the established quality
assurance objectives and support the usefulness of the demonstration results in verifying the
performance of the GORE-SORBER Screening Survey.
A qualitative performance assessment of the GORE-SORBER Screening Survey indicated that (1) all
63 modules installed at the SBA and CSC sites were retrieved without sample loss, resulting in 100
percent completeness; (2) the sampler is easy to use and requires minimal training (a 10-minute training
video is available from the developer); (3) logistical requirements for the GORE-SORBER Screening
Survey require that the samplers be installed using a manual push tool, left in place for several days,
retrieved by hand, and sent to the developer for analysis; and (4) sample handling in the field requires
that sorbent be properly containerized and shipped to the developer. Other factors that may affect the
performance range of the GORE-SORBER Screening Survey but that were not evaluated during the
demonstration are sampling depth, time allowed for sampling, type and amount of sorbent material
placed in the GORE-SORBER module, and ability of vapors to move across the module membrane.
The demonstration results indicate that the GORE-SORBER Screening Survey can provide useful,
cost-effective data for environmental problem-solving. The GORE-SORBER modules successfully
collected soil gas samples in clay and sandy soils. The sampler provided positive identification of target
compounds and may detect lower concentrations of VOCs in the soil gas than can the reference
method. Based on the results of this demonstration, there appears to be a general correlation between
the GORE-SORBER Screening Survey and reference method data. However, at higher contaminant
levels, the ratio between the mass of contaminant detected in the soil gas using the GORE-SORBER
module and the concentration of contaminant detected using the reference method decreases. As with
any technology selected, the user must determine what is appropriate for the application and the project
data quality objectives.
40
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Chapter 8
Technology Update
Guidelines for Use of GORE-SORBER® module in Water Quality Monitoring
The GORE-SORBER Screening Survey has been validated and applied on more than 1,200 projects
since 1992. When placed in the screened, saturated interval of a monitoring well or piezometer, the
waterproof, vapor-permeable GORE-TEX® (ePTFE) membrane collector housing allows for water/air
partitioning (in accordance with Henry s Law) of dissolved-phase organic compounds while preventing
transfer of liquid water and eliminating impact from suspended solids on the adsorbent. Outlined below
are some general guidelines for use and installation of passive, adsorbent-based GORE-SORBER
collectors in monitoring wells as a means of qualitatively screening water quality as part of a
groundwater monitoring program.
• GORE-SORBER collectors can be used to reduce the frequency of groundwater purging and
sampling for petroleum and chlorinated organic chemicals, including polynuclear aromatic
hydrocarbons (PAHs).
• We recommend an initial round of testing consisting of matrix (water) sampling and testing by
conventional means and testing using GORE-SORBER modules. The deployment and retrieval
of the GORE-SORBER modules should occur prior to any purging/sampling of the well for
matrix testing purposes in order to establish a baseline relationship at this site between the
matrix concentration data and the sorber mass data. The results will then be plotted on a scatter
diagram to show the site-specific relationship between groundwater concentration and mass on
the GORE-SORBER® module.
• Subsequent testing uses only GORE-SORBER modules to monitor trends in water quality over
time on an individual well basis.
• Periodic purging and sampling with concurrent GORE-SORBER collector monitoring is
recommended every four to six sampling events. To ensure comparability of the data, the
periodic matrix samples must be collected and analyzed in a consistent manner.
Chapter 8 was written solely by W.L. Gore & Associates. The statements presented in this chapter
represent the vendor s point of view and summarize the claims made by the vendor regarding the
GORE-SORBER Screening Survey. Publication of this material does not represent the EPA s
approval or endorsement of the statements made in this chapter; results of the performance
evaluation of the GORE-SORBER Screening Survey are discussed in other chapters of this report.
41
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• Modules should be placed adjacent to the screened interval in the monitoring well, not in the
headspace of the well or outside the screened interval to avoid any stagnation effects.
• Modules should not be placed in direct contact with free product (that is, liquid hydrocarbons
or solvents).
• Only a 2-day exposure period is required for modules deployed directly in groundwater. This
exposure period has been derived experimentally as part of our validation.
• GORE-SORBER Screening Survey modules can be used to test for toluene, ethlybenzene, and
xylene, petroleum hydrocarbons, chlorinated solvents, and many SVOCs, such as polynuclear
aromatic hydrocarbons (PAHs). Application for ethers, alcohols, ketones, or most other highly
water-soluble compounds has not been validated at this time.
• Information relative to the site, the well construction, and matrix sampling and testing
procedures being used will be useful for data interpretation purposes.
• Monitoring wells being used as soil vapor extraction (SVE) points are not suitable to this
application.
NELAC Certification of Screening Modules Laboratory
The W.L. Gore & Associates, Inc. Screening Modules Laboratory has been certified to be in
conformance with the National Environmental Laboratory Accreditation Conference (NELAC) Chapter
5, Quality System Standards, adopted in July, 1997 by U.S. EPA, federal and state officials as the
national environmental laboratory performance standard for the United States.
CRREL Study
In a field comparison by the U.S. Army Corps of Engineers Cold Regions Research Engineering
Laboratory (CRREL) in Hanover, New Hampshire, the GORE-SORBER Screening Survey was
compared to an in-vial sample handling and analysis method for estimating volatile organic compound
contamination in the near surface vadose zone. The two methods, although very different
operationally, yielded similar results for trichloroethane contamination. The correlation (R2 = 0.944)
between the two methods was far better than those between the in-vial method and conventional soil
sample collection and handling techniques. Copies of CRREL Special Report 96-14 are available from
W.L. Gore & Associates, Inc.
Chapter 8 was written solely by W.L. Gore & Associates. The statements presented in this chapter
represent the vendor s point of view and summarize the claims made by the vendor regarding the
GORE-SORBER Screening Survey. Publication of this material does not represent the EPA s
approval or endorsement of the statements made in this chapter; results of the performance
evaluation of the GORE-SORBER Screening Survey are discussed in other chapters of this report.
42
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Chapter 9
Previous Deployment
The GORE-SORBER Screening Survey has been applied at more than 1,200 sites around the world
since 1992. It has been used at many small and large industrial facilities, at petroleum refining, bulk
storage and retail facilities, at military sites, and at Department of Energy sites. The GORE-SORBER
Screening Survey has been approved by state environmental regulatory agencies and by regional offices
of EPA in site-specific work plan documents for RI/FS and Resource Conservation and Recovery Act
(RCRA) Facility Investigations under the Comprehensive Environmental Response, Compensation, and
Liability Act/Superfund Amendments and Reauthorization Act and RCRA. Case studies for a variety of
applications are available from W.L. Gore & Associates, Inc.
Chapter 9 was written solely by W.L. Gore & Associates. The statements presented in this chapter
represent the vendor s point of view and summarize the claims made by the vendor regarding the
GORE-SORBER Screening Survey. Publication of this material does not represent the EPA s
approval or endorsement of the statements made in this chapter; results of the performance
evaluation of the GORE-SORBER Screening Survey are discussed in other chapters of this report.
43
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References
Ecology & Environment. 1996. 'Expanded Site Inspection for the Albert City, SB A Site, Albert City,
Iowa. " July.
Engineering-Science, Inc. 1991. "Remedial Investigation/Feasibility Report for the Chemical Sales
Company Superfund Site, OU1, Leyden Street Site. "
PRC Environmental Management, Inc. 1997. "Final Demonstration Plan for the Evaluation of Soil
Sampling and Soil Gas Sampling Technologies. "
Tetra Tech EM Inc. 1997. " Soil and Soil Gas Technology Evaluation Report. "
W.L. Gore & Associates (Gore). 1996. Approved Quality Assurance Manual Number QAM-
1.10/25/96, Revisions.
Gore. 1997. GORE-SORBER® Product Schematic
U.S. Environmental Protection Agency. 1986. Test Methods for Evaluating Solid Waste. SW-846.
Third Edition.
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APPENDIX A
DATA SUMMARY TABLES
FOR THE
W.L. GORE & ASSOCIATES, INC.
GORE-SORBER® SCREENING SURVEY
PASSIVE SOIL GAS SAMPLING SYSTEM
A-l
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>
to
TABLE Al. VOLATILE ORGANIC COMPOUND CONCENTRATIONS
FOR GORE AND REFERENCE DATA
SBA SITE - GRID 1
Sample
Name
Sample
Location
Soil
Type
Contaminant Concentration ^ig/sample)
Vinyl Chloride
Total DCE
1,1-DCA|1,1,1-TCA| TCE
PCE
GORE SAMPLER DATA
137567 - GORE
137568 - GORE
137564 - GORE
137565 - GORE
137563 - GORE
137562 - GORE
137566 - GORE
Quantitation Limit
A5
B6
C4
D4
E2
Fl
G4
-
Fine
Fine
Fine
Fine
Fine
Fine
Fine
-
399
663
618
1,051
781
1,281
1,640
1.77
621
630
608
665
550
507
560
0.02
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
2.80
4.11
2.80
1.17
0.70
1.36
0.86
0.02
0.14
0.11
0.08
0.05
0.02
0.02
0.03
0.03
Range:
Mean:
399 - 1,640
919
507 - 665
592
0.01
0.01
0.02 0.70-4.110.02-0.14
0.02
1.97
0.06
Sample
Name
Sample
Location
Soil
Type
Contaminant Concentration (ng/L)
Vinyl Chloride
Total DCE
1,1-DCA|1,1,1-TCA| TCE
PCE
REFERENCE SAMPLING METHOD DATA
ACTAG1A105.0
ACTAG1B605.0
ACTAG1C105.0
ACTAG1D605.0
ACTAG1E705.0
ACTAG1F405.0
ACTAG1G605.0
Al
B6
Cl
D6
E7
F4
G6
Fine
Fine
Fine
Fine
Fine
Fine
Fine
230,224
3,830,535
2,808,445
1,059,056
3,102,754
517,255
5,178,313
343,072
2,223,217
1,705,212
640,633
1,218,334
297,770
279,336
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
Notes:
Gore Data:
Reference Data:
Range: 230,000-5,180,000279,000-2,220,000 50
Mean: 2,390,000 958,000 50
Quantitation limits are listed in the last row of the table.
Values reported as 50 are actually non-detects at a detection limit of 50 ng/L.
50
50
50
50
50
50
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TABLE A2. VOLATILE ORGANIC COMPOUND CONCENTRATIONS
FOR GORE AND REFERENCE DATA
SBA SITE - GRID 2
>
GO
Sample
Name
Sample
Location
Soil
Type
Contaminant Concentration ^ig/sample)
Vinyl Chloride
Total DCE
1,1-DCA|1,1,1-TCA| TCE
PCE
GORE SAMPLER DATA
137580 - GORE
137578 - GORE
137576 - GORE
137581 -GORE
137582 - GORE
137577 - GORE
137579 - GORE
Quantitation Limit
A5
B3
Cl
D5
E6
F2
G4
-
Fine
Fine
Fine
Fine
Fine
Fine
Fine
-
1.77
1.77
1.77
1.77
1.77
1.77
1.77
1.77
2.85
0.76
1.80
4.01
5.23
14.6
13.1
0.02
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
163
69.9
71.1
79.4
99.1
152
120
0.02
1.58
1.26
1.23
0.88
0.77
0.88
0.54
0.03
Range:
Mean:
1.77
1.77
0.76-14.6 0.01
0.02 69.9-1630.54-1.58
6.04
0.01
0.02
108
1.02
Sample
Name
Sample
Location
Soil
Type
Contaminant Concentration (ng/L)
Vinyl Chloride
Total DCE
1,1-DCA
1,1,1-TCA| TCE
PCE
REFERENCE SAMPLING METHOD DATA
ACTAG2A405.0
ACTAG2B605.0
ACTAG2C305.0
ACTAG2D205.0
ACTAG2E605.0
ACTAG2F505.0
ACTAG2G705.0
A4
B6
C3
D2
E6
F5
G7
Fine
Fine
Fine
Fine
Fine
Fine
Fine
100
100
100
100
100
100
100
50
50
50
151
50
58
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
491
560
508
5,378
323
1,283
183
50
50
50
50
50
50
50
Range:
Mean:
100 50-151 50 50 183-5,380 50
100 65 50 50 1,250 50
Notes:
Gore Data:
Reference Data:
Quantitation limits are listed in the last row of the table.
Values reported as 50 (or 100 for vinyl chloride) are actually non-detects at a detection limit of 50 ng/L
(or 100 ng/L for vinyl chloride).
-------
TABLE A3. VOLATILE ORGANIC COMPOUND CONCENTRATIONS
FOR GORE AND REFERENCE DATA
SBA SITE - GRID 4
Sample
Name
Sample
Location
Soil
Type
Contaminant Concentration (ig/sampler)
Vinyl Chloride
Total DCE
1,1-DCA
1,1,1-TCA
TCE
PCE
GORE SAMPLER DATA
137571 - GORE
137572 - GORE
137574 - GORE
137569 - GORE
137575 - GORE
137573 - GORE
137570 - GORE
Quantitation Limit
A3
B5
C6
D2
E7
F5
G3
-
Fine
Fine
Fine
Fine
Fine
Fine
Fine
-
1.77
1.77
1.77
1.77
1.77
1.77
1.77
1.77
1.09
1.40
0.84
3.21
1.17
0.87
1.08
0.02
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
228
327
209
254
136
163
51.6
0.02
0.51
1.08
0.38
0.41
0.22
0.27
0.08
0.03
Range:
Mean:
1.77 0.84-3.21 0.01 0.02
1.77 1.38 0.01 0.02
51.6-327 0.08- 1.08
195 0.42
Sample
Name
Sample
Location
Soil
Type
Contaminant Concentration (ng/L)
Vinyl Chloride
Total DCE
1,1-DCA
1,1,1-TCA
TCE
PCE
REFERENCE SAMPLING METHOD DATA
ACTAG4A305.0
ACTAG4B505.0
ACTAG4C105.0
ACTAG4D205.0
ACTAG4E405.0
ACTAG4F305.0
ACTAG4G105.0
A3
B5
Cl
D2
E4
F3
Gl
Fine
Fine
Fine
Fine
Fine
Fine
Fine
100
100
100
100
100
100
100
50
195
261
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
3,429
14,259
33,558
744
1,088
3,330
9,295
50
50
50
50
50
50
50
Range:
Mean:
100 50-261 50 50 744-33,600 50
100 101 50 50 9,390 50
Notes:
Gore Data:
Reference Data:
Quantitation limits are listed in the last row of the table.
Values reported as 50 (or 100 for vinyl chloride) are actually non-detects at a detection limit of 50 ng/L
(or 100 ng/L for vinyl chloride).
-------
TABLE A4. VOLATILE ORGANIC COMPOUND CONCENTRATIONS
FOR GORE AND REFERENCE DATA
SBA SITE - GRID 5
>
en
Sample
Name
Sample
Location
Soil
Type
Contaminant Concentration ^ig/sample)
Vinyl Chloride
Total DCE
1,1-DCA|1,1,1-TCA| TCE
PCE
GORE SAMPLER DATA
137557 - GORE
137559 - GORE
137554 - GORE
137561 -GORE
137555 - GORE
137556 - GORE
137558 - GORE
Quantitation Limit
A4
B5
C2
D6
E2
F3
G5
-
Fine
Fine
Fine
Fine
Fine
Fine
Fine
-
1.77
3.62
3.43
1.77
2.80
2.51
3.47
1.77
44.8
19.4
69.3
16.2
119
79.2
69.7
0.02
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
15.4
8.90
28.3
18.1
50.5
46.9
75.5
0.02
0.08
0.04
0.14
0.03
0.14
0.08
0.08
0.03
Mean:
1.77-3.62
2.77
16.2 - 119
59.7
0.01
0.01
0.02 8.90-75.50.03-0.14
0.02
0.08
Sample
Name
Sample
Location
Soil
Type
Contaminant Concentration (ng/L)
Vinyl Chloride
Total DCE
1,1-DCA|1,1,1-TCA| TCE
PCE
REFERENCE SAMPLING METHOD DATA
ACTAG5A405.0
ACTAG5B605.0
ACTAG5C405.0
ACTAG5D705.0
ACTAG5E205.0
ACTAG5F705.0
ACTAG5G705.0
A4
B6
C4
D7
E2
F7
G7
Fine
Fine
Fine
Fine
Fine
Fine
Fine
100
275
100
8,265
100
4,889
100
5,544
4,773
8,745
17,865
3,175
21,028
8,734
50
50
50
50
50
50
50
50
50
50
50
50
50
50
355
1,222
545
6,253
132
2,710
2,867
50
50
50
50
50
50
50
Range: 100-8,270 3,180-21,000 50 50
Mean: 1,980 9,980 50 50
132-6,250 50
2,010 50
Notes:
Gore Data: Quantitation limits are listed in the last row of the table.
Reference Data: Values reported as 50 (or 100 for vinyl chloride) are actually non-detects at a detection limit of 50 ng/L
(or 100 ng/L for vinyl chloride).
-------
TABLE A5. VOLATILE ORGANIC COMPOUND CONCENTRATIONS
FOR GORE AND REFERENCE DATA
SBA SITE - GRID 6
Sample
Name
Sample
Location
Soil
Type
Contaminant Concentration ^ig/sample)
Vinyl Chloride
Total DCE
1,1-DCA| 1,1,1-TCA| TCE
PCE
GORE SAMPLER DATA
137583 - GORE
137587 - GORE
137585 - GORE
137584 - GORE
137586 - GORE
137588 - GORE
137592 - GORE
Quantitation Limit
Al
B5
C3
Dl
E4
F5
G6
-
Fine
Fine
Fine
Fine
Fine
Fine
Fine
-
1.77
1.77
1.77
1.77
1.77
1.77
1.77
1.77
0.02
0.23
0.02
0.07
0.06
0.81
0.06
0.02
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.03
0.03
0.03
0.03
0.03
0.03
0.03
0.03
Mean:
1.77
1.77
0.02 -0.81
0.18
0.01
0.01
0.02
0.02
0.02
0.02
0.03
0.03
Sample
Name
Sample
Location
Soil
Type
Contaminant Concentration (ng/L)
Vinyl Chloride
Total DCE
1,1-DCA| 1,1,1-TCA
TCE
PCE
REFERENCE SAMPLING METHOD DATA
REFERENCE SAMPLES NOT ANALYZED IN THIS GRID
Notes:
Gore Data:
Quantitation limits are listed in the last row of the table.
-------
TABLE A6. VOLATILE ORGANIC COMPOUND CONCENTRATIONS
FOR GORE AND REFERENCE DATA
CSC SITE - GRID 1
Sample
Name
Sample
Location
Soil
Type
Contaminant Concentration (ig/sample)
Total DCE
1,1-DCA
1,1,1-TCA
TCE
PCE
GORE SAMPLER DATA
137604 - GORE
137607 - GORE
137605 - GORE
137608 - GORE
137602 - GORE
137603 - GORE
137606 - GORE
Quantitation Limit
A3
B6
C4
D6
E2
F2
G5
-
Coarse
Coarse
Coarse
Coarse
Coarse
Coarse
Coarse
-
188
100
175
96.0
228
239
242
0.02
0.01
0.01
0.12
0.13
0.16
0.01
0.15
0.01
32.6
32.3
46.1
50.3
28.4
40.0
38.4
0.02
271
208
284
214
287
282
243
0.02
404
417
433
405
413
397
405
0.03
Range: 96.0-242 0.01-0.16 28.4-50.3 208-287 397-433
Mean: 181 0.08 38.3 255 411
Sample
Name
Sample
Location
Soil
Type
Contaminant Concentration (ng/L)
Total DCE
1,1-DCA
1,1,1-TCA
TCE
PCE
REFERENCE SAMPLING METHOD DATA
ACTCG1A505.0
ACTCG1B605.0
ACTCG1C405.0
ACTCG1D405.0
ACTCG1E205.0
ACTCG1F305.0
ACTCG1G605.0
A5
B6
C4
D4
E2
F3
G6
Coarse
Coarse
Coarse
Coarse
Coarse
Coarse
Coarse
7,242
2,255
21,311
12,637
19,039
6,246
6,683
500
500
500
500
500
500
500
7,526
170,724
670,474
411,390
478,451
225,933
236,256
26,349
7,450
77,382
44,031
54,857
14,739
67,632
249,342
79,017
769,940
438,473
480,887
117,979
170,967
Notes:
Gore Data:
Reference Data:
Range: 2,260-21,300 500 7,530-670,0007,450-77,40079,000-770,000
Mean: 10,800 500 314,000 41,800 330,000
Quantitation limits are listed in the last row of the table.
Values reported as 500 are actually non-detects at a detection limit of 500 ng/L
-------
>
oo
TABLE A7. VOLATILE ORGANIC COMPOUND CONCENTRATIONS
FOR GORE AND REFERENCE DATA
CSC SITE - GRID 2
Sample
Name
Sample
Location
Soil
Type
Contaminant Concentration ^ig/sample)
Total DCE
1,1-DCA| 1,1,1-TCA
TCE
PCE
GORE SAMPLER DATA
137613 -GORE
137614 -GORE
137612 -GORE
137609 - GORE
137611 -GORE
137615 -GORE
137610 -GORE
Quantitation Limit
A6
B7
C4
Dl
E3
F7
Gl
-
Coarse
Coarse
Coarse
Coarse
Coarse
Coarse
Coarse
-
88.7
96.2
101
81.9
80.9
115
102
0.02
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
32.4
33.9
41.9
43.8
31.9
40.5
38.8
0.02
327
335
330
299
296
331
308
0.02
343
351
357
328
307
367
332
0.03
Range: 80.9-115 0.01 31.9-43.8 296-335 307-367
Mean: 95.2 0.01 37.6 318 341
Sample
Name
Sample
Location
Soil
Type
Contaminant Concentration (ng/L)
Total DCE
1,1-DCA| 1,1,1-TCA
TCE
PCE
REFERENCE SAMPLING METHOD DATA
ACTCG2A405.0
ACTCG2B405.0
ACTCG2C505.0
ACTCG2D405.0
ACTCG2E105.0
ACTCG2F205.0
ACTCG2G405.0
A4
B4
C5
D4
El
F2
G4
Coarse
Coarse
Coarse
Coarse
Coarse
Coarse
Coarse
500
500
942
1,708
2,694
2,827
3,780
500
500
500
500
500
500
500
33,875
138,681
219,486
353,483
413,456
415,093
439,087
11,353
42,596
76,171
99,223
123,487
119,787
153,683
31,950
101,902
201,050
222,623
288,770
287,739
427,089
Notes:
Gore Data:
Reference Data:
Range: 500-3,780 500 33,900-439,00011,400-154,00032,000-427,000
Mean: 1,850 500 288,000 89,500 233,000
Quantitation limits are listed in the last row of the table.
Values reported as 500 are actually non-detects at a detection limit of 500 ng/L
-------
TABLE A8. VOLATILE ORGANIC COMPOUND CONCENTRATIONS
FOR GORE AND REFERENCE DATA
CSC SITE - GRID 4
Sample
Name
Sample
Location
Soil
Type
Contaminant Concentration ^ig/sample)
Total DCE
1,1-DCA
1,1,1-TCA
TCE
PCE
GORE SAMPLER DATA
137616 -GORE
137618 -GORE
137619 -GORE
137620 - GORE
137617 -GORE
137621 - GORE
137622 - GORE
Quantitation Limit
Al
B4
C5
D7
E3
F7
G7
-
Coarse
Coarse
Coarse
Coarse
Coarse
Coarse
Coarse
-
201
194
184
217
185
190
155
0.02
0.13
0.01
0.01
0.01
0.10
0.13
0.01
0.01
35.3
32.1
33.4
24.4
28.7
31.3
26.2
0.02
263
258
242
273
257
259
209
0.02
360
350
340
362
352
367
324
0.03
Range: 155-217 0.01-0.13 24.4-35.3 209-273 324-367
Mean: 189 0.06 30.2 252 351
Sample
Name
Sample
Location
Soil
Type
Contaminant Concentration (ng/L)
Total DCE
1,1-DCA
1,1,1-TCA
TCE
PCE
REFERENCE SAMPLING METHOD DATA
ACTCG4A405.0
ACTCG4B305.0
ACTCG4C105.0
ACTCG4D605.0
ACTCG4E405.0
ACTCG4F105.0
ACTCG4G305.0
A4
B3
Cl
D6
E4
Fl
G3
Coarse
Coarse
Coarse
Coarse
Coarse
Coarse
Coarse
7,008
500
6,882
3,964
10,513
6,650
7,823
500
500
500
500
500
500
500
168,233
19,627
162,682
115,537
216,980
123,393
184,170
20,043
1,881
21,872
15,855
41,798
21,178
32,812
143,142
20,753
152,164
129,093
388,861
194,826
313,472
Notes:
Gore Data:
Reference Data:
Range: 500-10,500 500 19,600-217,0001,880-41,80020,800-389,000
Mean: 6,190 500 142,000 22,200 192,000
Quantitation limits are listed in the last row of the table.
Values reported as 500 are actually non-detects at a detection limit of 500 ng/L
-------
TABLE A9. VOLATILE ORGANIC COMPOUND CONCENTRATIONS
FOR GORE AND REFERENCE DATA
CSC SITE - GRID 5
>
o
Sample
Name
Sample
Location
Soil
Type
Contaminant Concentration ^ig/sample)
Total DCE
1,1-DCA
1,1,1-TCA
TCE
PCE
GORE SAMPLER DATA
137626 - GORE
137624 - GORE
137627 - GORE
137625 - GORE
137628 - GORE
137629 - GORE
137623 - GORE
Quantitation Limit
A5
B2
C6
D3
E7
F7
Gl
-
Coarse
Coarse
Coarse
Coarse
Coarse
Coarse
Coarse
-
78.2
53.5
88.9
40.3
80.0
72.0
42.5
0.02
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
21.2
25.5
16.7
20.7
25.0
23.9
23.1
0.02
219
227
213
189
239
239
195
0.02
321
345
292
328
342
343
315
0.03
Range: 40.3-88.9 0.01 16.7-25.5 189-239 292-345
Mean: 65.0 0.01 22.3 217 327
Sample
Name
Sample
Location
Soil
Type
Contaminant Concentration (ng/L)
Total DCE
1,1-DCA
1,1,1-TCA
TCE
PCE
REFERENCE SAMPLING METHOD DATA
ACTCG5A105.0
ACTCG5D505.0
ACTCG5E405.0
ACTCG5F105.0
ACTCG5G705.0
Al
D5
E4
Fl
G7
Coarse
Coarse
Coarse
Coarse
Coarse
545
744
500
500
1,401
500
500
500
500
500
67,314
78,631
58,536
12,571
132,480
8,995
12,097
9,166
2,429
24,684
76,084
99,169
71,940
24,812
220,317
Range: 500 - 1,400 500 12,600 - 132,0002,430 - 24,70024,800 - 220,000
Mean: 738 500 69,900 11,500 98,500
Notes:
Gore Data: Quantitation limits are listed in the last row of the table.
Reference Data: Values reported as 500 are actually non-detects at a detection limit of 500 ng/L
------- |