United States Office of Research and EPA/600/R-00/074
Environmental Protection Development August 2000
Agency Washington, D.C. 20460
&EPA Environmental Technology
Verification Report
Groundwater Sampling
Technologies
Burge Environmental, Inc.
Multiprobe 100
Sandia
National
Laboratories
ETV ETY ET
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THE ENVIRONMENTAL TECHNOLOGY VERIFICATION
PROGRAM
KAlViA
Y
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ETV JOINT VERIFICATION STATEMENT
TECHNOLOGY TYPE: GROUNDWATER SAMPLING TECHNOLOGIES
APPLICATION: VOC-CONTAMINATED WATER SAMPLING
TECHNOLOGY NAME: Multiprobe 100
COMPANY: Surge Environmental
ADDRESS:
WEBSITE:
EMAIL:
6100 South Maple Ave. Suite 114
Tempe, AZ 85283
www.burgenv.com
burgenv@primenet.com
PHONE: (602) 968-5141
FAX: (602) 894-1675
The U.S. Environmental Protection Agency (EPA) has created the Environmental Technology
Verification Program (ETV) to facilitate the deployment of innovative or improved environmental
technologies through performance verification and dissemination of information. The goal of the ETV
Program is to further environmental protection by substantially accelerating the acceptance and use of
improved and cost-effective technologies. ETV seeks to achieve this goal by providing high-quality,
peer-reviewed data on technology performance to those involved in the design, distribution, financing,
permitting, purchase, and use of environmental technologies.
ETV works in partnership with recognized standards and testing organizations and stakeholder groups
consisting of regulators, buyers, and vendor organizations, with the full participation of individual
technology developers. The program evaluates the performance of innovative technologies by
developing test plans that are responsive to the needs of stakeholders, conducting field or laboratory tests
(as appropriate), collecting and analyzing data, and preparing peer-reviewed reports. All evaluations are
conducted in accordance with rigorous quality assurance protocols to ensure that data of known and
adequate quality are generated and that the results are defensible.
The Site Characterization and Monitoring Technologies Pilot, one of 12 technology areas under ETV, is
administered by EPA's National Exposure Research Laboratory. Sandia National Laboratories, a
Department of Energy laboratory, is one of the verification testing organizations within the ETV Site
Characterization and Monitoring Pilot. Sandia collaborated with personnel from the US Geological
Survey to conduct a verification study of groundwater sampling technologies. This verification
statement provides a summary of the results from a verification test of the Multiprobe 100 sampler
manufactured by Burge Environmental.
EPA-VS-SCM-43 The accompanying notice is an integral part of this verification statement.
August 2000
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DEMONSTRATION DESCRIPTION
In August 1999, the performance of six groundwater sampling devices was evaluated at the US
Geological Survey Hydrological Instrumentation Facility at the NASA Stennis Space Center in
southwestern Mississippi. Each technology was independently evaluated in order to assess its
performance in the collection of volatile organic compound- (VOC) contaminated water.
The verification test design incorporated the use of a 5-inch diameter, 100-foot standpipe at the USGS
facility. The standpipe, serving as an "above-ground" well, was filled with tap water spiked with various
concentration levels of six target volatile organic compounds. The target compounds (1,2-
dichloroethane, 1,1-dichloroethene, trichloroethene, benzene, 1,1,2-trichloroethane, and
tetrachloroethene) were chosen to represent the range of VOC volatility likely to be encountered in
normal sampler use. Water sampling ports along the exterior of the standpipe were used to collect
reference samples at the same time that groundwater sampling technologies collected samples from the
interior of the pipe. A total of seven trials were carried out at the standpipe. The trials included the
collection of low (-20 |Jg/L) and high (-200 |Jg/L) concentrations of the six target VOC compounds in
water at sampler depths ranging from 17 to 91 feet. A blank sampling trial was also included in the test
matrix.
The standpipe trials were supplemented with additional trials at groundwater monitoring wells in the
vicinity of sites with VOC-contaminated groundwater at the NASA Stennis facility. The sampling
devices were deployed in a number of 2-inch and 4-inch wells, along with co-located submersible
electric gear pumps as reference samplers. The principal contaminant at the onsite monitoring wells was
trichloroethene. The onsite monitoring provided an opportunity to observe the operation of the sampling
system under typical field-use conditions.
All technology and reference samples were analyzed by two identical field-portable gas chromatograph-
mass spectrometer (GC/MS) systems that were located at the test site during the verification tests. The
GC/MS analytical method used was a variation of EPA Method 8260 purge-and-trap GC/MS,
incorporating a headspace sampling system in lieu of a purge and trap unit. The overall performance of
the groundwater sampling technologies was assessed by evaluating sampler precision and comparability
with reference samples. Other logistical aspects of field deployment and potential applications of the
technology were also considered in the evaluation.
Details of the demonstration, including an evaluation of the sampler's performance, may be found in the
report entitled Environmental Technology Verification Report: Burge Environmental Inc., Multiprobe
100, EPA/600/R-00/074.
TECHNOLOGY DESCRIPTION
The Multiprobe 100 is a discrete, multi-level sampler that is designed for permanent deployment in a
well. The sampler is designed for use with a complementary automated wellhead analyzer for TCE
called the Optrode. Only the sampling module was evaluated in this test. Optrode performance was not
evaluated in this demonstration.
The Multiprobe 100 consists of two units with tubing and wiring interconnections. A upper receiving
module which is deployed at the wellhead on top of the well is 18 inches long, 3.25 inches in diameter,
and weighs 3 pounds. The lower sampling module, which is inserted into the water column inside the
well, is 12 inches long, 3.25 inches in diameter and also weighs 3 pounds. The system is constructed of
Teflon, borosilicate glass, stainless steel and Delrin®, a solvent-resistant, acetal homopolymer resin.
Electrical solenoid valves are used to select the sampling level and control gas flow to the sampler.
Water level sensors in the water chambers of both modules are used to trigger valve changes during the
sampling process. A small, battery-operated microprocessor controller is used to control the valves used
during the sampling process.
EPA-VS-SCM-43 The accompanying notice is an integral part of this verification statement. August 2000
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The lower sampling module is filled with water from the selected sampling level by hydrostatic pressure.
The water sample is then pushed up to the upper receiving module by pressurizing the sampling chamber
headspace with nitrogen gas. Samples can be manually dispensed into analysis vials from the upper
receiving module, however, the system is primarily intended for interconnection with automated
analyzers, such as the Optrode, which would also be positioned at the wellhead.
The system also has the ability to purge volatile organic compounds from water in situ with subsequent
analysis by sensors, such as the Optrode, that are positioned in the headspace or at the wellhead.
Following the purge, the vapors can also be transported via tubing to the surface for collection and
analysis. The in situ purge capability of the sampler was not tested in this investigation.
VERIFICATION OF PERFORMANCE
The following performance characteristics of the Multiprobe 100 groundwater sampling system were
observed:
Precision: The precision of the sampler was determined through the collection of a series of replicate
samples from two standpipe trials using low (-20 |Jg/L) and high (-200 |Jg/L) VOC concentrations at 17,
35, 53 and 91-foot depths. Each trial included 6 target VOCs at each of the sampling depths, resulting in
a total of 24 cases per trial. Multiprobe 100 precision, represented by the relative standard deviation, for
all compounds at all concentrations and sampling depths evaluated in this study ranged from 3 to 21%
with a median value of 9.4 %. In 27 of the 48 cases, the Multiprobe 100 was less precise than the
reference sample set. The F-ratio test was used to assess whether precision differences between
Multiprobe 100 and reference samples were statistically significant. Test results showed that precision
differences between the Multiprobe 100 and reference samples were statistically insignificant at the 95%
confidence level in 46 of the 48 test cases.
Comparability with a Reference: Multiprobe 100 sampler results from the standpipe trials were
compared with results obtained from reference samples that were collected at the same time. Both
Multiprobe 100 and reference samples were analyzed by the same method using the same GC/MS
system. Sampler comparability is expressed as percent difference relative to the reference data. Sampler
differences for all target VOC compounds at all concentrations and sampler depths in this study ranged
from -30 to 15%, with a median percent difference of -5%. The t-test for sample means was used to
assess whether the observed differences between Multiprobe 100 and reference samplers were
statistically significant. These tests revealed that in 31 of 48 trials, differences were statistically
indistinguishable from 0% at the 95% confidence level. Of the remaining 17 cases that were statistically
different from 0%, 16 showed a negative Multiprobe 100 sampler bias. Statistically significant negative
sampler bias ranged from - 10 to - 30%.
Versatility: Sampler versatility is the consistency with which it performed with various target
compounds, concentration levels, and sampling depths. In terms of precision, Multiprobe 100
performance was generally consistent at the range of concentrations and collection depths evaluated in
this study. The Multiprobe 100 showed a trend toward negative bias for 11DCE and TCE and the
sampler showed consistently negative bias for PCE at all concentrations and sampler depths. As a result
of its physical size, the Multiprobe 100 cannot be installed in wells with diameters less than 4 inches.
In light of these considerations, the Multiprobe 100 sampler in its aqueous sampling mode is judged to
have limited versatility.
Logistical Requirements: The Multiprobe 100 is designed for permanent installation in 4-inch or larger
wells. The installation would require either custom installation by Burge Environmental personnel or
user installation following approximately two days of training. Although the system is optimized for
EPA-VS-SCM-43 The accompanying notice is an integral part of this verification statement. August 2000
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automated operation, it can also be used in a manual mode. The system is also capable of being removed
from one installation for redeployment in a second well however several hours of disassembly and re-
assembly time would be required. The system also requires a source of compressed nitrogen at the
wellhead.
Overall Evaluation: The results of this verification test show that the Multiprobe 100 multi-level
sampler can be used to collect VOC-contaminated water samples that are generally statistically
comparable to reference samples. Sampler recoveries for PCE in the aqueous sampling and transfer
mode were consistently low when compared to reference samples. Further investigation of sampler
performance for this compound may be required. The Multiprobe 100 is a component of an overall
automated sampling and analysis system. Only the sampler module was evaluated in this test. A
complete system evaluation would be warranted prior its deployment in long term automated monitoring
applications.
As with any technology selection, the user must determine if this technology is appropriate for the
application and the project data quality objectives. For more information on this and other verified
technologies visit the ETV web site at http://www.epa.gov/etv.
Gary J. Foley, Ph.D
Director
National Exposure Research Laboratory
Office of Research and Development
Samuel G. Varnado
Director
Energy and Critical Infrastructure Center
Sandia National Laboratories
NOTICE: EPA verifications are based on evaluations of technology performance under specific, predetermined
criteria and appropriate quality assurance procedures. The EPA and SNL make no expressed or implied
warranties as to the performance of the technology and do 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. Mention of commercial product names does not imply endorsement.
EPA-VS-SCM-43 The accompanying notice is an integral part of this verification statement.
August 2000
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EPA/600/R-00/074
August 2000
Environmental Technology
Verification Report
Groundwater Sampling
Technologies
Burge Environmental Inc.
Multiprobe 100
by
Wayne Einfeld
Sandia National Laboratories
Albuquerque, New Mexico 87185
and
Eric N. Koglin
U.S. Environmental Protection Agency
Environmental Sciences Division
National Exposure Research Laboratory
Las Vegas, Nevada 89193-3478
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Notice
The U.S. Environmental Protection Agency (EPA), through its Office of Research and Development (ORD),
funded and managed, through Interagency Agreement No. DW66940927 with Sandia National Laboratories,
the verification effort described herein. This report has undergone peer and administrative review and has
been approved for publication as an EPA document. Mention of trade names or commercial products does not
constitute endorsement or recommendation for use of a specific product.
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Table of Contents
List of Figures iv
List of Tables iw
Acknowledgments v
Abbreviations and Acronyms vi
1 INTRODUCTION 1
Background 1
Demonstration Overview 1
2 TECHNOLOGY DESCRIPTION: BURGE ENVIRONMENTAL MULTIPROBE 100 SAMPLER 3
3 DEMONSTRATION PROCESS AND DESIGN 7
Introduction 7
Site Description 7
Verification Test Design Summary 9
Test Design Elements 9
Sampler Performance Parameters 11
Sample Analysis 12
Data Processing 12
Data Quality Control 12
Verification Test Plan 13
Standpipe Sampling Matrix 13
Chronological Summary of Demonstration Activities 14
Deviations from the Verification Plan 15
4 MULTIPROBE 100 PERFORMANCE EVALUATION 17
Introduction 17
Sampler Precision 17
Sampler Comparability 17
Blank Test Results 21
Monitoring Well Results 21
Sampler Versatility 21
Deployment Logistics 21
Performance Summary 21
5 MULTIPROBE 100 TECHNOLOGY UPDATE AND REPRESENTATIVE APPLI CATIONS 23
6 REFERENCES 27
APPENDIX
A: QUALITY SUMMARY FOR ANALYTICAL METHOD 29
ill
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List of Figures
1 Burge Environmental Multiprobe 100 Sampling System 4
2 The Burge Multiprobe 100 Receiving Module 4
3 The Burge Multiprobe 100 Sampling Module 5
4 Sampling sequences for the Burge Multiprobe 100 sampler 6
5 The standpipe at the USGS Hydrological Instrumentation Facility 8
6 Multiprobe 100 precision from the standpipe trials 19
7 Multiprobe 100 comparability with reference samples from the standpipe trials 19
8 A schematic diagram of the Multiprobe 100 interfaced to an onsite analysis module 24
9 A schematic diagram of an automated analysis module for TCE 25
A-l Calibration check control chart for TCE on GC/MS #1 30
A-2 Calibration check control chart for TCE on GC/MS #2 31
A-3 Calibration check control chart for PCE on GC/MS #1 31
A-4 Calibration check control chart for PCE on GC/MS #2 32
A-5 GC/MS system check relative percent differences 32
List of Tables
1 Construction Details of Groundwater Monitoring Wells 9
2 Target VOC compounds 10
3 Multiprobe 100 Verification Trials at the Standpipe 13
4 Multiprobe 100 Deployments at Groundwater Monitoring Wells 14
5 Precision Summary for Multiprobe 100 and Reference Sampler 18
6 Comparability of Multiprobe 100 and Reference Sampler Data from Standpipe Trials 20
7 Performance Summary for Multiprobe 100 22
A-l Onsite GC/MS-Headspace Method Quality Control Measures 29
IV
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Acknowledgments
The authors acknowledge the support of all those who helped in the vendor solicitation, planning, field
deployment, and analysis phases of this verification test. In particular, we recognize Steve Gardner (US EPA
NERL, Las Vegas) who provided technical assistance and peer reviewed the test plan. We also acknowledge
the assistance of Eugene Hays, Bill Davies, and Ed Ford (US Geological Survey) in providing access to the
Standpipe Facility at the NASA Stennis Space Center as well as for their administrative and logistical support
during the standpipe and groundwater monitoring trials. We also thank Ronald McGee and Jenette Gordon
(NASA, Environmental Management) for their willingness to grant us access to the groundwater monitoring
wells at the NASA Stennis Space Center. Thanks also to Greg New (Foster Wheeler Environmental
Corporation) for his assistance in getting much of the site hydrological and well monitoring data into our
hands during the planning phases of this test. Finally, we thank Craig Crume and Mika Geenfield (Field
Portable Analytical) for their long hours, care, and diligence in onsite sample analysis during the field trials.
For more information on the Groundwater Sampling Technology Verification Test, contact
Eric Koglin Wayne Einfeld
Pilot Manager ETV Project Manager
Environmental Protection Agency Sandia National Laboratories
Environmental Sciences Division MS-0755 P.O. Box 5800
National Exposure Research Laboratory Albuquerque, NM 87185-0755
P.O. Box 93478 (505) 845-8314 (v)
Las Vegas, NV 89193-3478 E-mail: weinfel@sandiagov
(702) 798-2432 (v)
E-mail: koglin.eric@epa.gov
For more information on the Burge Environmental Multiprobe-100 sampler, contact:
Scott Burge
Burge Environmental
6100 South Maple, Suite 114
Tempe, AZ 85283
602-968-5141 (v)
E-mail: burgenv@primenet.com
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Abbreviations and Acronyms
BNZ
DIFF
EPA
ETV
GC/MS
HIF
MSL
MW
NASA
ND
NERL
PCE
PTFE
QA
QC
RSD
SCMT
SNL
SP
ssc
TCE
USGS
VOC
12DCA
11DCE
112TCA
Benzene
Difference
US Environmental Protection Agency
Environmental Technology Verification Program
Gas chromatograph-mass spectrometer
Hydrological Instrumentation Facility
Mean sea level
Monitoring well
National Aeronautics and Space Administration
Not detected
National Exposure Research Laboratory
Tetrachloroethene
Polytetrafluoroethylene
Quality assurance
Quality control
Relative standard deviation
Site Characterization and Monitoring Technologies Pilot
Sandia National Laboratories
Sample port
Stennis Space Center
Trichloroethene
US Geological Survey
Volatile organic compound
1,2-dichloroethane
1,1-dichloroethene
1,1,2-trichloroethane
VI
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Section 1 — Introduction
Background
The U.S. Environmental Protection Agency (EPA)
has created the Environmental Technology
Verification Program (ETV) to facilitate the
deployment of innovative or improved
environmental technologies through performance
verification and dissemination of information. The
goal of the ETV Program is to further
environmental protection by substantially
accelerating the acceptance and use of improved
and cost-effective technologies. ETV seeks to
achieve this goal by providing high-quality, peer-
reviewed data on technology performance to those
involved in the design, distribution, financing,
permitting, purchase, and use of environmental
technologies.
ETV works in partnership with recognized
standards and testing organizations and
stakeholder groups consisting of regulators,
buyers, and vendor organizations, with the full
participation of individual technology developers.
The program evaluates the performance of
innovative technologies by developing test plans
that are responsive to the needs of stakeholders,
conducting field or laboratory tests (as
appropriate), collecting and analyzing data, and
preparing peer-reviewed reports. All evaluations
are conducted in accordance with rigorous quality
assurance (QA) protocols to ensure that data of
known and adequate quality are generated and that
the results are defensible.
ETV is a voluntary program that seeks to provide
objective performance information to all of the
participants in the environmental marketplace and
to assist them in making informed technology
decisions. ETV does not rank technologies or
compare their performance, label or list
technologies as acceptable or unacceptable, seek
to determine "best available technology," or
approve or disapprove technologies. The program
does not evaluate technologies at the bench or
pilot scale and does not conduct or support
research.
The program now operates 12 pilots covering a
broad range of environmental areas. ETV has
begun with a 5-year pilot phase (1995-2000) to
test a wide range of partner and procedural
alternatives in various pilot areas, as well as the
true market demand for and response to such a
program. In these pilots, EPA utilizes the expertise
of partner "verification organizations" to design
efficient processes for conducting performance
tests of innovative technologies. These expert
partners are both public and private organizations,
including federal laboratories, states, industry
consortia, and private sector facilities. Verification
organizations oversee and report verification
activities based on testing and QA protocols
developed with input from all major
stakeholder/customer groups associated with the
technology area. The demonstration described in
this report was administered by the Site
Characterization and Monitoring Technologies
(SCMT) Pilot. (To learn more about ETV, visit
ETV's Web site at http://www.epa.gov/etv.)
The SCMT pilot is administered by EPA's
National Exposure Research Laboratory (NERL).
Sandia National Laboratories, one of two
verification organizations associated with the
SCMT pilot, conducted a verification study of
groundwater sampling technologies during the
summer of 1999. Groundwater sampling
technologies are commonly employed at
environmental sites for site screening and
characterization, remediation assessment, and
routine environmental monitoring. Groundwater
sampling technologies generally fall into two
categories: (1) active systems, including pumping
systems and discrete-level grab systems; and (2)
passive or diffusional systems. Both types of
samplers were evaluated during this verification
study.
Demonstration Overview
In August 1999, a demonstration study was
conducted to verify the performance of six
groundwater sampling devices: SamplEase
(bladder pump, Clean Environment Equipment,
Oakland, CA), Micro-Flo (bladder pump, Geolog
Inc., Medina, NY), Well Wizard Dedicated
Sampling System (bladder pump, QED
Environmental, Ann Arbor, MI), Kabis Sampler
(discrete-level grab sampler, Sibak Industries,
Solano Beach, CA), and GoreSorber (diffusional
sampler, W. L. Gore and Associates, Elkton, MD).
This report contains an evaluation of the
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Multiprobe 100 manufactured by Burge
Environmental (Tempe, AZ).
The scope of this technology demonstration was
purposely limited to sampling device performance
parameters such as precision, comparability with a
reference measurement, and where applicable,
deployment logistics. Several of the systems
tested in this study are intended for use with low
volume sampling protocols—a relatively new
approach to the collection of a representative
sample from a groundwater monitoring well. This
study was specifically intended to evaluate
sampling device performance and was not an
evaluation of the merits of a low flow purge and
sampling protocol. This protocol has been
proposed, tested, and published elsewhere [Puls
and Barcelona, 1996] and is beyond the scope of
this particular investigation.
The demonstration was conducted in August of
1999 at the National Aeronautic and Space
Administration (NASA) Stennis Space Center in
southwestern Mississippi. Sandia worked in
cooperation with the US Geological Survey
(USGS), a federal agency resident at the NASA
Stennis site, and used a 100-foot standpipe testing
facility associated with the USGS Hydrological
Instrumentation Facility (HIF) located on the
NASA site. The standpipe, serving as an "above-
ground" well, was filled with water spiked with
various concentration levels of six target volatile
organic compounds (VOCs). Water sampling
ports along the exterior of the pipe permitted the
collection of reference samples at the same time
that groundwater sampling technologies collected
samples from the interior of the pipe.
For most of the participating technologies, the
standpipe trials were supplemented with additional
trials at a number of groundwater monitoring wells
at sites with VOC-contaminated groundwater at
the NASA Stennis facility. The devices were
deployed in a number of 2-inch and 4-inch wells
and, where possible, reference samples were
collected for comparison with each sampling
device. The principal contaminant at the site was
trichloroethene.
All technology and reference samples were
analyzed by the same field-portable gas
chromatograph-mass spectrometer system that was
located at the test site during the verification tests.
The overall performance of the groundwater
sampling technologies was assessed by
comparison of technology and reference sample
results for a number of volatile organic
compounds with particular attention given to key
parameters such as sampler precision and
comparability with reference sample results.
Aspects of field deployment and potential
applications of the technology was also
considered.
A brief outline of this report is as follows: Section
2 contains a brief description of the Multiprobe
100 sampler and its capabilities. Section 3
outlines a short description of the test facilities and
a summary of the verification test design. Section
4 includes a technical review of the data with an
emphasis on assessing overall sampler
performance. Section 5 presents a summary of the
Multiprobe 100 sampler and provides examples of
potential applications of the sampler in
groundwater monitoring settings. Appendix A
includes an assessment of quality control data
associated with the analytical method used in this
study.
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Section 2 — Technology Description: Burge Environmental
Multiprobe 100 Sampler
This section provides a general description and
overview of the capabilities of the Multiprobe 100
multi-level sampler manufactured by Burge
Environmental. Burge Environmental provided
the information used to prepare this section.
The Multiprobe 100 is a sampler designed for
permanent deployment in a well and has the
capacity for collecting samples from up to eight
discrete levels within a well. The sampler is
designed for use with a complementary automated
wellhead analyzer for TCE called the Optrode®
however, the Optrode was not evaluated in this
demonstration.
The Multiprobe 100 consists of two units with
wiring and tubing interconnections (Figure 1).
The upper receiving module, which is deployed at
the wellhead and on top of the well, is 18 inches
long and 3.25 inches in diameter. The lower
sampling module, which is inserted into the water
column in the well, is 12 inches long and 3.25
inches in diameter. The receiving and sampling
modules each weigh about 3 pounds. The system
is constructed of Teflon, borosilicate glass,
stainless steel and Delrin®, a crystalline plastic
composed of acetal resin made by the
polymerization of formaldehyde. A
microprocessor controller is included in the system
to coordinate the valve sequencing during the
sampling process.
A more detailed description of sampler
configuration and operation follows: The
Multiprobe 100 consists of a sampling and a
receiving module as shown in Figure 1. The
receiving module, shown in Figure 2, consists of a
sample chamber with an internal water level
sensor, a sample bottle, and several electrical
solenoid valves for directing the flow of the water
sample. The receiving module is positioned atop
the well casing outside the well. The sampling
module, shown in Figure 3, consists of a sample
collection chamber fitted with an interior water
level sensor and four solenoid valves and
associated sampling lines that are deployed to
different levels within the well. The sampling
module is positioned approximately 2 to 3 feet
below the static water level in the monitoring well.
The sampling and receiving modules are inter-
connected by an electrical cable, enabling control
of sampling module's valves and water level
sensor. The cable also encases a nitrogen gas line
used to pressurize the sampling module and a
Teflon tubing line that is used to transport the
water sample from the sampling module to the
receiving module.
The sampling process is initiated by opening one
of the four sampling module inlet valves. Each of
the four valves is connected to a length of Teflon
tubing that is positioned at a pre-determined
sampling depth within the monitoring well. When
the sampling chamber is vented to the atmosphere,
the lower chamber fills through the sampling tube,
being driven by the hydrostatic pressure head as
shown in Figure 4, Step 1. The water continues to
flow into the sample collection chamber until it
contacts the water level sensor located near the top
of the chamber, whereupon the sampling valve and
vent line are automatically closed. Prior to
placement into the well, the position of the water
sensor inside the sampling module can be set to
collect a water volume between 100 to 200 mL.
Following sample collection, nitrogen is used to
pressurize the headspace in the sampling chamber.
The water flows through a bottom port in the
sampling module, up through the interconnecting
tubing, and into the receiving module, as shown in
Figure 4, Steps 2 and 3. The water sample fills the
receiving module chamber until a second water-
level sensor inside this chamber is activated. At
this point, the remaining water and pressurized
nitrogen in the tubing is diverted to a waste
container. The water sample contained in the
chamber is then manually transferred into a
sample bottle as shown in Figure 4, Step 4. The
upper receiving module serves as a common
collection and analysis point from the multiple
sampling lines and by inclusion of a headspace in
the collection volume, enables analysis of selected
VOC contaminants in the headspace volume.
The sampler requires a cylinder of compressed
nitrogen at the wellhead. The line pressure
required is usually less than 30 psi, allowing the
collection of hundreds of samples before cylinder
recharge or replacement is necessary. The only
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moving parts of the ground-water sampling system
are electrically controlled valves. The system is
capable of years of operation without replacement
of electrical components.
The cost of the four-level groundwater sampling
system, as configured for this test, was $3,000.
Additional information on potential applications of
the system for environmental characterization and
monitoring can be found in Section 5—Technology
Updates and Application.
I II I
Sunken
faceting Mwftulc
Well Caxin
Tubing*!! O
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— i'mhfsi§ Wtih
j iJcctric. >
arid
i £inH*wi-ifejj£r LtfVei
i ApprojumMdy 2 l«st 3 I1
GROUND-WATER SAMPLING SYSTEM
-
TuSc
RECEIVING MOOULE
Figure 1. Burge Environmental Multiprobe
100 Sampling System.
Figure 2. The Burge Multiprobe 100 Receiving
Module.
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Cabling t"r™n
tceiviTif Mmlule
"*Wsth Ktertrie, Water
Well
Casing
Walcr
" Nilrogcn
Sample Collection
Chamber
Vtal/Pressare
WMET Selection
ing Tyfee
Figure 3. The Burge Multiprobe 100 Sampling Module.
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Step One: Filling
1, Vein valve (1} opens w
aunosphcre.
2. Water selection valve
121 ojwn in desired d*plh.
3. Water -sample flows
into sample collection
etawha until water sensor
SlepThrwL Filling
I. VBIH valve {6} open to
2, Water from ihe lower
module passes ihraugh the
shul-off" valve (4) filling the
sample chamber until water
s«ns«»r f 7) is aciivaUd
SlepTwn; Enprring
I. Shut-off %'atv« {4}
operas ajkrwing water to be
pwtied to receiving
2. Pressure valve (S>
preMurues Ihe sample
ccrilection chamber to push
the vnm& sample out of
chambec
L»«*.
'
Step Four: Sample Collection
L Waler sensor adivited,
shutting off water flow to the
sample chamber.
Dncrsism valve (8| opens,
sending water aid nitrogen
remaining in tube betweea upper
anil lower modules 10 wasl«,
3. Transfer valve (9) opens
iranKi'errtng water in sample
chamher to sample bollle I' 10).
SAMPLING MODULE
RECEIVING MODULE
Figure 4. Sampling sequences for the Burge Multiprobe 100 sampler.
-------
Section 3 — Demonstration Process and Design
Introduction
The principal objective of this demonstration was
to conduct an independent evaluation of the
capabilities of several ground-water sampling
technologies for VOC-contaminated water. A
number of key performance parameters were
chosen to evaluate overall sampler performance.
In order to ensure data integrity and authenticity of
results, data quality control measures were also
incorporated into the study design. The design
was developed by personnel at Sandia National
Laboratories with concurrence from the various
technology vendors participating in the study.
Technical review of the study design was also
provided by EPA personnel with professional
expertise in the area of groundwater sampling. A
complete demonstration plan has previously been
published [Sandia, 1999].
Site Description
The John C. Stennis Space Center in southwest
Mississippi is one often NASA field centers in the
United States. It is NASA's primary center for
testing and flight-certifying rocket propulsion
systems for the Space Shuttle and future generations
of space vehicles. Over the years, SSC has evolved
into a multiagency, multidisciplinary center for
federal, state, academic and private organizations
engaged in space, oceans, environmental programs
and national defense. The USGS is a one of the
resident agencies at the NASA-Stennis complex
and operates a number of testing facilities as a part
of its Hydrologic Instrumentation Facility. This
facility supports USGS agency-wide hydrologic
data-collection activities through the identification
of agency needs, development of technical
specifications, and testing and evaluation.
Standpipe Facility - One of the HIF test centers is
known as the Standpipe Facility. The facility was
designed by Doreen Tai, an HIF chemical
engineer, and is housed in a Saturn V rocket
storage building at the Stennis complex. A
schematic diagram of the Standpipe and
accessories is shown in Figure 5. The Standpipe is
an above-ground, 100-foot-long, 5-inch-diameter,
stainless steel pipe with numerous external
sampling ports along its length. Two large tanks
at the top of the Standpipe are used to prepare
solutions that can then be drained into the
Standpipe. The tanks are equipped with motor-
driven mixing propellers and floating lids to
minimize loss of volatile compounds during
solution mixing and transfer. An external
Standpipe fill line at the bottom of the pipe enables
the pipe to be filled from the bottom up, thereby
minimizing flow turbulence and VOC losses in the
prepared solutions. The external access ports
allow reference samples to be taken
simultaneously with the collection of technology
samples inside the pipe. As shown in Figure 5, the
indoor facility has six levels of access, including
the ground floor, and a freight elevator services all
levels. In this demonstration, the Standpipe was
used in a series of controlled water sampling trials.
Technology vendors sampled VOC-contaminated
water solutions from the Standpipe while reference
samples were simultaneously taken from the
external ports.
Site Hydrogeology-The second phase of this
technology demonstration involved the collection
of groundwater samples from six onsite wells at
SSC. The site has about 200 wells that have been
used for subsurface plume characterization and
routine groundwater monitoring. The shallow,
near-surface geology where most of the
contaminant plumes are located can be
summarized as follows [Foster Wheeler, 1998]:
The geology generally consists of a thin veneer of
clayey sediments know as Upper Clay, found at
elevations ranging from 10 to 30 feet above mean
sea level (MSL). These overlay a sandy unit
named the Upper Sand (at 5 to 15 feet above
MSL). The Upper Sand is underlain by a second
clayey unit named the Lower Clay and a second
sandy unit called the Lower Sand (at -35 to 5 feet
MSL). Below the Lower Sand another clayey unit
is present which represents an unnamed or
undifferentiated Pleistocene deposit. This deposit
is underlain by a thick zone of inter-bedded sand
and clay deposits that form the Citronelle
Formation (at -100 to -40 feet MSL). The VOC
contamination is present in the Upper Sand and
Lower Sand water-bearing zones;
correspondingly, most of the wells selected for use
in this test were screened in these zones.
-------
5 IN. DIA.-
SP14^ f&
5P13 i
5P12
SP11
SPIO
SPS
5P6
SPS
5P2
TANKS
I OP
LEVEL S
IN, DIA. FILL/OfiAIN LlhE
LEVEL 4
SP - SAMPLING PORT
SP DISTANCE FROM TO5 WATER LEVEL
LEVEL 3
SPi 54 ft.
SP7 64 ft.
SP4 82 Ft.
5P2 32 Ft.
LEVEL 2
/EXIT LINE
Figure 5. The standpipe at the USGS Hydrological Instrumentation Facility.
-------
Groundwater Monitoring Wells—Construction
information for the six wells selected for use in
this study is given in Table 1. The wells were
constructed with either 2 or 4-inch-diameter PVC
pipe with 10-foot poly vinyl chloride (PVC) screen
length. All samples were collected at the
midscreen level. Typical sampling depths for the
wells selected for study ranged from about 15 to
85 feet from the top of the well column to the
screen midpoint. Depth of the water column
above the mid-screen point ranged from 5 to 68
feet for the wells selected for use in this study.
Verification Test Design Summary
The verification test design consisted of two basic
elements. The first was a test matrix, consisting of
several trials conducted under carefully controlled
sampling conditions at the standpipe. These trials
enabled the evaluation of sampler performance
parameters such as precision and comparability
with reference. The second element was an
additional series of tests conducted under actual
field conditions with inherently less experimental
control. These trials presented an opportunity to
observe the technology in actual field use in
conditions very similar to those that would be
encountered in routine use. Together, these two
study elements provided a data set that is adequate
for an overall performance assessment of these
groundwater sampling devices for applications
specifically involving the sampling of VOC-
contaminated groundwater.
Test Design Elements
The test consisted of a variety of sampling
activities carried out under relatively closely
controlled experimental conditions at the
standpipe, along with field sampling at selected
onsite monitoring wells under less controlled
conditions. Additional design element
descriptions are given below. The participating
technologies were split into two categories, active
samplers and passive samplers, with individual
sampling trials designed specifically for these two
sampler categories.
Target VOCs—Six target compounds, all
regulated under the US EPA Clean Water Act,
were selected for testing in this study. The
compounds were 1,2-dichloroethane (12DCA),
1,1-dichloroethene (11DCE), trichloroethene
(TCE), benzene (BNZ), tetrachloroethene (PCE),
and 1,1,2-trichloroethane (112TCA). With the
exception of benzene, all of these compounds are
chlorinated and have regulatory limits of 5 |jg/L in
water as presented in the Clean Water Act. The
six compounds selected encompass a range of
volatility, a parameter that is likely to influence
sampler performance. Target compound volatility,
as represented by Henry's constants and boiling
point information, is given in Table 2.
Table 1. Construction Details of Groundwater Monitoring Wells
Well
No.
06-04
06-10
06-11
06-20
12-09
12-12
TOC
(ft, MSL)
28.8
7.8
15.3
7.3
28.0
28.4
Total
Depth
(ft)
39.0
87.0
150.0
75.0
18.0
99.0
Screen Elev.
(ft, MSL)
Top
-1.3
-55.2
-62.8
-55.4
18.0
-11.0
Bottom
-11.3
-65.2
-72.8
-65.4
8.0
-21.0
Well
Diam.
(in)
2
4
4
4
2
4
Install
Date
04/95
04/95
05/95
12/96
05/95
05/95
Depth
to
Water
(ft)
24.6
8.2
15.2
7.8
10.0
11.6
Water
Level
(ft,
MSL)
4.2
-0.4
0.1
-0.6
18.0
16.8
Water Depth
Above
Screen
Midpoint
(ft)
10.5
59.8
67.9
59.8
5.0
32.8
Notes: TOC = top of well column; water levels from most recent quarterly well monitoring data
-------
Table 2. Target VOC compounds
Compound
Tetrachloroethene (PCE)
1,1-Dichloroethene(11DCE)
Trichloroethene (TCE)
Benzene (BNZ)
1 ,2-Dichloroethane (12DCA)
1,1,2-Trichloroethane
(112TCA)
Henry's Constant
(kg* bar/mole at 298 K)a
High (17.2)
High (29.4)
Mid (10.0)
Mid (6.25)
Low (1.39)
Low (0.91)
Boiling Pt.
(°C)
121
32
87
80
84
114
1 Henry's constant data from NIST, 2000.
Test Concentrations—The use of the standpipe
facility enabled the preparation of water mixtures
containing the six target VOCs in a range of
concentration levels. In four standpipe testing
trials, the target compound concentration was
either low (10-20 |ag/L) or high (175-225 |ag/L)
concentration. Spike solutions of all six target
compounds were prepared in methanol from neat
compounds. Normally a 5-10 mL volume of the
spiking solution was injected into the mixing tank,
which was located at the top of the standpipe and
contained about 100 gallons of tap water. This
solution was covered with a floating lid to reduce
volatile losses, gently mixed for 5 minutes, and
then drained into the standpipe.
Standpipe Reference Samples—Preliminary studies
at the standpipe revealed volatile losses of target
compounds during mixing and filling.
Consequently calculated spike concentrations
could not be used as a reference values in this
study. The standpipe has external sampling ports
along its length so that reference samples could be
collected simultaneously with sampling from the
interior of the pipe using the samplers undergoing
testing. Each sampling trial consisted of the
simultaneous collection of replicate test device and
reference samples at a fixed concentration and
sampling depth. The reference samples were
collected directly into analysis vials with no
intervening pumps or filters that could affect the
sample. Replicate sampling allowed the
determination of test device and reference sample
precision. Precision in this context incorporates
the variability of the technology and the reference
sample in combination with the common
analytical method used on both sample types. The
reference sample precision is assumed to be the
baseline level with which the technology precision
data can be directly compared for each of the
sampling trials.
Sampler Blank—The standpipe trials included a
blank test where replicate samples were collected
from a blank water mixture in the standpipe. This
test was conducted to assess whether the
construction materials in the various samplers
were a possible source of contamination of the
sample for the six target compounds used in this
study.
Sampler Carryover—One of the intended
applications of several of the samplers involved in
the study is the collection of a water sample with
relatively low VOC levels at a discrete level in a
well that may have overlying layers of VOC
contamination at higher levels. A so-called clean-
through-dirty test was incorporated to assess the
degree to which the samplers were contaminated
in the high-level layer that was penetrated as the
sampler was lowered to a cleaner underlying layer
in the well. The results of these trials are also
expressed in terms of percent difference from
reference samples, with recovery values
significantly greater than zero indicating sampler
contamination for the overlying contaminated
layers in the well. Since the Multiprobe 100
sampler is intended for permanent well
installation, it was not included in this optional
trial.
Groundwater Well Reference Samples—Sixonsite
groundwater monitoring wells were selected for
use in the second phase of the study. For most of
the participating technologies, a reference sampler
was co-located in the monitoring well along with
the technology to provide a means of comparison.
The Multiprobe 100 test was an exception in this
case. The 3.75-inch diameter of the Multiprobe
100 sampling module prevented the simultaneous
10
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deployment of a reference sampler in the well,
since limited annular space between the
Multiprobe 100 exterior and the internal
circumference of the well was available.
Deployment of the Multiprobe 100 was done at
two wells without co-located samples only for the
purposes of observing its deployment and use in
actual field settings.
Sampler Performance Parameters
Four performance parameters were evaluated in
the assessment of each sampling device. They are
briefly outlined in the following paragraphs.
Precision—Sampler precision was computed for
the range of sampling conditions included in the
test matrix by the incorporation of replicate
samples from both the standpipe and the
groundwater monitoring wells in the study design.
The relative standard deviation was used as the
parameter to estimate precision. The percent
relative standard deviation is defined as the sample
standard deviation divided by the sample mean
times 100, as shown below:
RSD(%) = J 2=4-
• 100
Here, Xt is one observation in a set of n replicate
samples where X is the average of all
observations, and n is the number of observations
in the replicate set. In assessment of sampler
precision, a statistical test was used to assess
whether observed differences between the
reference sample precision and the technology
sample precision are statistically significant.
Specifically, the F-ratio test compares the variance
(square of the standard deviation) of the two
groups to provide a quantitative assessment as to
whether the observed differences between the two
variances are the result of random variability or
the result of a significant influential factor in either
the reference or technology sample groups
[Havlicek and Grain 1988a].
Comparability—The inclusion of reference
samples, collected simultaneously with technology
samples from the external sampling port of the
standpipe, allows the computation of a
comparability-to-reference parameter. The term
comparability is to be distinguished from the term
accuracy. Earlier investigations at the standpipe
revealed that volatility losses occurred when
mixing and transporting the spike mixtures during
standpipe filling. As a result, the "true"
concentrations of target VOCs in the standpipe
were not precisely known and thus an accuracy
determination is not warranted. Alternatively, a
reference measurement from the external port,
with its own sources of random error, is used for
comparison. The term percent difference is used
to represent sampler comparability for each of the
target compounds in the sampling trials at the
standpipe. Percent difference is defined as
follows:
where is XM the average reported concentration
of all technology sample replicates and X ™t is the
average reported concentration of all reference
sample replicates. The statistical t-test for two
sample means was used to assess observed
differences between the reference and technology
means for each sampling trial [Havlicek and Grain,
1988b]. The t-test gives the confidence level
associated with the assumption that the observed
differences are the result of random effects among
a single population only and that there is no
significant bias between the technology and
reference.
Versatility — The versatility of the sampler was
evaluated by summarizing its performance over
the volatility and concentration range of the target
compounds as well as the range of sampling
depths used in the standpipe trials. A sampler that
is judged to be versatile operates with acceptable
precision and comparability with reference
samples over the range of experimental conditions
included in this study. Those samplers judged to
have low versatility may not perform with
acceptable precision or comparability for some of
the compounds at some of the tested sampling
depths or concentration levels.
Field Deployment Logistics — This category refers
to the logistical requirements for deployment of
the sampler under its intended scope of
application. This is a more subjective category
that incorporates field observations made during
sampler deployment at the groundwater
monitoring wells. Logistical considerations
include such items as personnel qualifications and
11
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training, ancillary equipment requirements, and
field portability.
Operator Influence-The sampling technician as
well as the sample collection method has an
influence on the overall quality of the samples
taken. This is particularly true for the active
samplers evaluated in this study. Such factors as
the time required to collect a sample and the
sampler flow rate may influence overall sample
quality. An evaluation of operator influence on
sample quality is beyond the scope of this study.
All sampler operators were experienced in the use
of their technologies and the assumption is made
that the technologies were being operated under
conditions that would yield the highest quality
samples.
Sample Analysis
A single analytical method was used for
technology and reference samples. All analyses
were conducted onsite, using analytical services
provided by Field Portable Analytical (Fremont,
CA). The onsite instrumentation consisted of two
identical field portable gas chromatograph-mass
spectrometer (GC/MS) units (Inficon, HAPSITE,
Syracuse, NY) equipped with a Inficon Headspace
Sampling System. The analysis method used was
a modified Method 8260 (purge-and-trap GC/MS)
with headspace sampling replacing the purge-and-
trap portion of the method [EPA, 1996]. Sample
throughput was on the order of 4 to 6 samples per
hour per instrument for a daily throughput of 60-
70 samples per instrument. The Inficon field-
portable GC/MS system with headspace vapor
sampling accessory had previously gone through
the ETV verification process. Results from this
verification study showed that system accuracy
and precision for VOC in water analysis was
comparable with a conventional fixed laboratory
analysis using purge-and-trap sample handling
combined with bench-top GC/MS analytical
systems [EPA, 1998].
A brief summary of the analytical method follows:
Samples were brought to the analysis location in
40-rnL VOA vials and kept at temperatures near 4
°C until they were prepared for instrument
analysis. As a result of the relatively high sample
throughput and the use of two instruments, sample
holding times did not exceed 24 hours in most
cases. Consequently, no sample preservatives
were used in the study. Immediately prior to
analysis, the chilled VOA sample vials were
uncapped and transferred to a 50-mL glass
syringe. Half (20 mL) of the sample was then
transferred to a second 40-rnL VOA vial and the
vial was immediately capped. A 5-|jL solution
containing internal standards and surrogate
standards was injected through the septum cap of
the vial. The vial was then placed in the
headspace sampling accessory and held at 60 °C
for 15 minutes. The original vial was again filled
with the remainder of the sample, capped, and held
under refrigeration as a spare.) Following the
temperature equilibration time, a vapor extraction
needle was inserted through the vial's septa cap
and into the headspace. A pump in the GC/MS
then sampled a fixed volume of headspace gas
through a heated gas transfer line and into a fixed-
volume gas sampling loop in the GC/MS. Under
instrument control, the gas sample was then
injected onto the capillary column for separation
and detection. An integrated data system
processed the mass detector data and output results
for the six target analytes plus internal and
surrogate standards in concentration format. The
method used internal standards (as outlined in
Method 8260) for computation of target compound
concentrations. Surrogate standard results were
used as measures of instrument data quality, along
with other quality control measures outlined
below.
Data Processing
The results from chemical analysis of both
technology and reference samples were compiled
into spreadsheets and the arithmetic mean and
percent relative standard deviation (as defined in
Section 3) were computed for each set of replicate
samples from each standpipe and monitoring well
trial. All data were reported in units of
micrograms per liter for the six target compounds
selected. Direct trial-by-trial comparisons were
then made between technology and reference
sample results as outlined below. All the
processed data from the verification study have
been compiled into data notebooks and are
available from the authors by request.
Data Quality Control
The desirability of credible data in ETV
verification tests requires that a number of data
quality measures be incorporated into the study
design. Additional details on data quality control
are provided in the following paragraphs.
Sample Management-Mi sampling activities were
documented by SNL field technicians using chain-
12
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of-custody forms. To save sample handling time
and minimize sample labeling errors in the field,
redundant portions of the chain-of-custody forms
and all sampling labels were preprinted prior to the
field demonstration.
Field Logbooks-field notes were taken by
observers during the standpipe and groundwater
well sampling trials. The notes include a written
chronology of sampling events, as well as written
observations of the performance characteristics of
the various technologies tested during the
demonstration.
Pre-demo Analytical System Audit-Prior to the
actual demonstration, a number of samples
containing the six target compounds at various
concentration levels were prepared at Sandia
National Laboratories and sent via overnight mail
in an icepack under refrigeration temperatures to
Field Portable Analytical near Sacramento, CA.
They were analyzed by GC/MS using the
headspace method intended for use in the final
field test. Results from this preliminary audit
revealed acceptable performance of the GC/MS
system and its accompanying method. The written
analytical method that was used during the full
demonstration was also reviewed and finalized at
this time.
Analytical Method-The analytical method was an
adaptation of EPA Method 8260B and followed
the data quality requirements outlined in the
method. Included in the list of data quality
measures were: (1) initial calibration criteria in
terms of instrument linearity and compound
recovery, (2) daily instrument calibration checks at
the onset and completion of each 12-hour analysis
shift, (3) blank sample instrument performance
checks, (4) internal standard recovery criteria, and
(5) surrogate standard recovery criteria. A
summary of the GC/MS analysis quality control
data for the demonstration period is given in
Appendix A.
Verification Test Plan
The preceding information, as well as that which
follows, is summarized from the Groundwater
Sampling Technologies Verification Test Plan
[Sandia, 1999], which was prepared by SNL and
met with concurrence by all vendor participants
prior to the field demonstration. The test plan
includes a more lengthy description of the site, the
role and responsibilities of the test participants,
and a discussion of the experimental design and
data analysis procedures.
Standpipe Sampling Matrix
The sampling matrix for the standpipe phase of the
demonstration is given in Table 3. All standpipe
and groundwater testing was carried out
sequentially, with the various participants
deploying their sampling devices one at a time in
either the standpipe or the groundwater monitoring
wells. A randomized testing order was used for
each trial. The standpipe test phase for the
Multiprobe 100 included three trials. Trial 1 was
carried out at four sampling depths with a low
concentration (10-20 u,g/L) standpipe mixture.
Trial 2 was carried out at same four sampling
depths with a high concentration (175-225 u,g/L)
standpipe mixture. In both of these trials, reference
samples were simultaneously collected from
external sampling ports adjacent to the Multiprobe
100 inlet locations.
Table 3. Multiprobe 100 Verification Trials at the Standpipe
Trial No.
1
2
3
Standpipe
Collection
Port
SP14
SP12
SP10
SP3
SP14
SP12
SP10
SP3
SP3
Sample
Collection
Depth
Low (17 ft)
Mid-Low (35 ft)
Mid-High (53 ft)
High (92 ft)
Low (17 ft)
Mid-Low (35 ft)
Mid-High (53 ft)
High (92 ft)
High (92 ft)
VOC Concentration
Level
Low (-20 ppb)
High (-200 ppb)
Blank
Number of
Replicates
5
5
5
5
5
5
5
5
3
Notes: In each trial, an equal number of reference samples were collected, from adjacent external standpipe sampling
ports, simultaneously with the device samples
13
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Trial 3 was a blank mixture measurement to test
the cleanliness of a new sampler. For this trial, the
standpipe was filled with tap water and three
replicates were collected by the Multiprobe 100
from the deepest (91 ft) location in the pipe while
three reference replicates were collected
simultaneously from the adjacent exterior
sampling port.
During the groundwater monitoring portion of the
test, the Multiprobe 100 was installed and operated
at two 4-inch diameter wells, as shown in Table 4.
The purpose of these deployments was to observe
the installation and operation of the sampling
device. The wells at which the Multiprobe 100
was deployed were non-detectable for TCE and
the analytical data are not included in this report.
The size and configuration of the Multiprobe 100
prevented the simultaneous co-location of a
reference sampler in the well, hence no
comparison data were collected. The data from
the standpipe trials were adequate for performance
assessment of such parameters as precision and
comparability with reference samples.
Chronological Summary of
Demonstration Activities
The demonstration began on Monday, August 9
and concluded on Tuesday, August 17. The first
four days of the demonstration were devoted to
testing those technologies designated "active
samplers." Included in this group were Burge
Environmental (multi-level sampler) Clean
Environment Equipment (bladder pump), Geolog
(bladder pump), QED Environmental (bladder
pump), and Sibak Industries (discrete-level grab
sampler). The second half of the demonstration
interval was devoted to testing the "passive
sampler" category of which W. L. Gore (sorbent
sampler) was the only participant. A short
briefing was held on Monday morning for all
vendor participants to familiarize them with the
standpipe facility and the adjacent groundwater
monitoring wells. Standpipe testing began for the
active sampler category at midmorning on
Monday and was completed on the following day.
Two days of testing at groundwater wells
followed. The passive sampler category tests were
begun at the standpipe Thursday, August 12 and
were completed on Monday, August 16. The
passive sampler category was also deployed at a
number of monitoring well sites simultaneously
with standpipe testing.
Sample analysis was carried out in a mobile
laboratory parked near the standpipe and was done
concurrently with field-testing. With the
exception of the first day of sample analysis, all
technology and matched-reference samples were
analyzed on the same instrument and usually on
the same day. This approach was taken to
minimize the possible influence of day-to-day
instrument variability on the analysis results.
The demonstration technical team recorded
observations during operation of the devices at the
standpipe and monitoring well trials with regard to
their logistical requirements and ease of use.
These observations also were used to document
any performance anomalies as well as the
technical skills required for operation.
Table 4. Multiprobe 100 Deployments at Groundwater Monitoring Wells
Well
06-1 OMW
06-20MW
Well
Diameter
(in)
4
4
Distance from Top
of Well to Screen
Mid- point (ft)
68.0
67.7
Water
Column
Depth
(ft)
59.8
59.9
Approximate
TCE Cone.
(H9/L)
< 5
< 5
Notes: Approximate TCE concentrations are derived from NASA contractor quarterly monitoring data.
14
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Deviations from the Verification
Plan
Under most field-testing environments,
circumstances often arise that prevent a complete
execution of the test plan, and this test was no
exception. A list of the deviations from the test
plan that are judged to be important are
summarized, along with an assessment of the
resulting impact on the field test data set.
Lost/dropped samples-Out of over 800 samples, 1
was dropped and lost in the field and 3 were not
analyzed either because they were overlooked or
lost in handling by the field technicians or
analysts. Because 4 or 5 replicates were collected
in each sampling trial, the loss of a few samples
does not affect the overall study results.
QC-flagged data-Several samples on the first day
of GC/MS operation were reported with low
internal standard recovery as a result of gas
transfer line problems. A close examination of
analyses data revealed that these results are
comparable with replicate sample results that
passed QC criteria. Consequently, these data were
used in the final analysis. A note indicating the
use of flagged data is included in the appropriate
data tables. No flagged data were encountered
with regard to the Multi-probe and associated
reference samples in this study.
Samples below quantitation limit ofGC/MS-One
of the wells sampled produced reference and
vendor samples that were at or below the practical
quantitation limit of the GC/MS system. These
data were manually re-processed by the analyst to
provide a concentration estimate. Where this
occurs, these data are flagged and appropriate
notice is given in the analysis section of this
report.
Blank GWMonitoring Wells-Six groundwater
monitoring wells were selected for study, based on
preliminary assessment of observed TCE
concentration levels using either historical data or
data from previous onsite well screening activities.
In three trials, well TCE concentration levels were
below the limits of detection, despite evidence to
the contrary from preliminary screening. Sampler
contamination during preliminary screening
carried out prior to the field test was determined to
be the cause of erroneously high readings. One of
the "blank" wells was kept in the data set to assess
sampler blank performance in the field. The other
wells were dropped from the list of trials. The
impact on the overall data set is not important,
since the objective parameters of performance
such as sampler precision and comparability with
reference are derived from the standpipe data.
15
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16
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Section 4 — Multiprobe 100 Performance Evaluation
Introduction
This section briefly discusses the results of test
data analysis and summarizes sampler
performance. Sampler precision, comparability
with reference sample data, and overall versatility
of the sampler for collection of VOC-
contaminated water are discussed. Only summary
data are given in this report. A complete
tabulation of all test data are available from the
authors via individual request.
Sampler Precision
The precision for both Multiprobe 100 and the
reference samples from the first four standpipe
trials is given in Table 5 and Figure 6. These four
trials consisted of low (10-20 |Jg/L) and high
(175-225 |Jg/L) target compound concentrations,
with 4 sample collection depths at 17, 35, 53 and
91 feet. Relative standard deviations are tabulated
for all of the 6 target compound to give a total of
48 cases. The final column in the table is the
result of an F-ratio test used to determine whether
the technology and reference sampler precision
can be regarded as statistically equivalent. Thep
value tabulated in the final column of the table is
an estimate of the probability of encountering the
observed difference in precision, if the assumption
is made that the two groups (technology and
reference) are equivalent. In statistical terms, this
is the null hypothesis and the accompanying
assumption is that only random influences are
present and no systematic bias is present among
the two sets of measurements. Values ofp that are
close to 1 reflect small differences in precision
with a corresponding high probability of
encountering differences of these magnitudes
under the null hypothesis. On the other hand,
values ofp less than 0.05 are indicative of
statistically significant differences that may
warrant a rejection of the null hypothesis.
Differences of such magnitude cannot be
satisfactorily explained by random variation alone
in the two sets of data being compared. If the
assumption is made that the two data sets are from
the same population, and only random effects are
occurring, the probability of observing a
difference in two precision values corresponding
to a 0.05 value ofp is 5%. For values ofp less
than 0.05, it is more likely that some systematic
bias exists between the two sets of data.
The highest uncertainty in the Multiprobe 100
results is observed for 12DCA at the low
concentration and 17-foot depth (Table 5). The
lowest uncertainty is observed for PCE at the high
concentration and 17-foot collection depth. The
median RSD for all compounds in all test cases
was 9.5% for the Multiprobe 100 samples and
8.6% for the reference samples. In 27 of the 48
cases, the Multiprobe 100 precision was greater
than the reference sampler precision. An even, or
nearly even, split of Multiprobe 100 RSD values
in the greater and less than categories would be
indicative of equivalence between the two
sampling methods. From a more formal statistical
point of view, the F-ratio test results indicate that
the tabulated values of p, with two exceptions, are
all greater than 0.05. This indicates that the
precision values for the Multiprobe 100 and the
reference samples are statistically equivalent and
that the observed differences are can be regarded
as random variation within a single population.
Sampler Comparability
Percent difference values were computed for each
of the six target compounds in the two standpipe
trials for a total of 48 cases and the results are
given in Table 6 and Figure 7. The percent
difference values for the Multiprobe 100 range
from -30 to 15% with a median value of-5%.
Overall, average percent difference values for 34
of the 48 cases shown in Table 6 were less than or
equal to 0% with 14 cases greater than 0%. An
even or nearly even split of percent difference
values in the greater than zero and less than zero
categories would be suggestive of equivalence
between the two sampling methods. In this case, a
predominance of negative differences is a
qualitative indication of negative sampler bias.
Negative percent differences are observed for
11DCE, TCE, and PCE under nearly all test
conditions. The other three compounds have a
more even distribution of positive and negative
percent differences.
T-test results show that 31 of the 48 trials have
values of p that are greater than 0.05 and thus can
17
-------
be considered statistically indistinguishable from
zero percent difference. The other 17 cases have
values ofp less than 0.05 and with one exception
all percent difference values are less than zero. Of
particular note is the fact that all tests cases
involving PCE show negative differences in the
range of-10 to -30%. Additionally, three of the 8
TCE test cases show statistically significant
negative differences, ranging from -16 to -24%.
The statistically significant low recoveries for
TCE and PCE might be attributable to headspace
losses or adsorption losses of VOCs in some of the
materials used in the construction of the sampler;
however, the identification of specific causative
factors is beyond the scope of this study.
Table 5. Precision Summary for Multiprobe 100 and Reference Sampler
Compound
11DCE
12DCA
BNZ
TCE
112TCA
PCE
Cone.
Level
Low
Low
Low
Low
High
High
High
High
Low
Low
Low
Low
High
High
High
High
Low
Low
Low
Low
High
High
High
High
Low
Low
Low
Low
High
High
High
High
Low
Low
Low
Low
High
High
High
High
Low
Low
Low
Low
High
High
High
High
Depth
(ft)
17
35
53
91
17
35
53
91
17
35
53
91
17
35
53
91
17
35
53
91
17
35
53
91
17
35
53
91
17
35
53
91
17
35
53
91
17
35
53
91
17
35
53
91
17
35
53
91
Multiprobe
100 Precision
(%RSD)
12.3
18.4
10.8
7.1
7.9
9.6
5.6
18.1
21.1
10.2
17.3
8.3
13.0
9.1
6.1
15.4
11.3
7.7
3.5
5.0
9.2
6.8
4.4
16.5
5.8
15.5
10.6
6.6
5.5
5.4
9.2
17.2
18.2
14.1
16.6
7.8
4.4
17.1
4.6
17.8
7.1
10.3
10.0
6.8
3.0
5.3
9.7
16.4
Ref.
Precision
(%RSD)
9.2
9.2
8.4
14.1
5.8
6.4
6.6
7.4
10.6
17.4
13.7
11.5
8.3
8.5
14.3
6.6
3.0
5.6
3.2
8.9
5.2
5.6
9.1
5.9
11.1
16.1
14.0
11.1
6.6
2.0
6.4
8.2
15.3
14.2
11.3
6.9
4.6
5.9
8.6
8.6
12.1
12.8
13.1
10.4
5.4
3.7
9.9
9.2
F-Ratio
Test
P
0.64
0.30
0.88
0.20
0.55
0.88
0.77
0.10
0.20
0.30
0.77
0.65
0.32
0.86
0.13
0.08
0.02
0.53
0.77
0.32
0.29
0.89
0.16
0.05
0.14
0.57
0.29
0.29
0.69
0.18
0.52
0.21
0.78
0.88
0.80
0.62
0.98
0.10
0.22
0.13
0.18
0.32
0.18
0.16
0.22
1.00
0.59
0.64
Note: Values ofp less than 0.05 are shown in bold.
18
-------
f.
i
D
i
-20 Mfllffi 17 ft
0 -330 MWL« 35 fl
•B
Figure 6. Multiprobe 100 precision from the standpipe trials.
O-10 CgrfL a 91 «
Q-ZD i^.'L .11 53 11
S-20 KgJL 3(35 fl
J
D^JOO t'ft'L a! 35 R
O-2001'g.lal 17 R
I
m
1
11DCE
12DCA
BMZ TCE
Compound
tIZTCA
PCE
Figure 7. Multiprobe 100 comparability with reference samples from the standpipe
trials.
19
-------
Table 6. Comparability of Multiprobe 100 and Reference Sampler Data
from Stand pipe Trials
Compound
11DCE
12DCA
BNZ
TCE
112TCA
PCE
Cone. Level3
Low
Low
Low
Low
High
High
High
High
Low
Low
Low
Low
High
High
High
High
Low
Low
Low
Low
High
High
High
High
Low
Low
Low
Low
High
High
High
High
Low
Low
Low
Low
High
High
High
High
Low
Low
Low
Low
High
High
High
High
Depth (ft)
17
35
53
91
17
35
53
91
17
35
53
91
17
35
53
91
17
35
53
91
17
35
53
91
17
35
53
91
17
35
53
91
17
35
53
91
17
35
53
91
17
35
53
91
17
35
53
91
Multiprobe
Difference (%)
-4
-11
-17
-2
1
-28
0
2
2
-2
7
9
9
-15
-5
11
7
2
-11
4
0
-11
-5
11
-16
-24
-15
-6
-3
-24
-2
-5
-2
-7
-10
15
5
-14
-5
12
-19
-27
-28
-30
-10
-30
-24
-28
t-Tesf(p)
0.55
0.21
0.01
0.81
0.87
<0.01
0.91
0.83
0.88
0.80
0.47
0.21
0.23
0.02
0.93
0.12
0.26
0.69
<0.01
0.44
0.92
0.02
0.30
0.23
0.02
0.03
0.07
0.32
0.45
<0.01
0.75
0.54
0.84
0.41
0.21
0.02
0.12
0.08
0.26
0.24
0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
a The low-level concentration was in the range of 10 to 20 ng/L for all 6 target
compounds. The high-level concentration was in the range of 175 to 250
jig/L.
b The t-test was used to compare the mean percent difference of the
Multiprobe 100 relative to the reference samples for each compound in each
trial. Small values ofp (<0.05) shown in bold are suggestive of sampler bias.
See text for further details.
20
-------
Blank Test Results
The analytical results from the blank trial at the
standpipe were all reported as non-detectable for
all target compounds for both the Multiprobe 100
and the reference samples. These results indicate
that a new or decontaminated sampler does not
measurably contaminate a clean sample of water.
Monitoring Well Results
As noted in Section 3, the Multiprobe 100 was
deployed at two groundwater monitoring wells to
observe its operation in a field setting. As a result
of the physical configuration of the Multiprobe
100 sampler, a reference pump could not be co-
located in the monitoring well and hence no
analytical data are available for inter-comparison.
The 4-inch diameter wells in which the sampler
was deployed were also non-detectable for TCE so
Multiprobe 100 precision data were not computed.
Observations of Multiprobe 100 deployment and
operation in these monitoring wells are
summarized in the following section entitled
Deployment Logistics.
Sampler Versatility
The data from the standpipe tests reveal that the
Multiprobe 100 samples are comparable to
reference samples with respect to precision. The
comparability data from the standpipe tests reveal
a number of statistically significant sampler biases
for PCE and to a lesser extent TCE. The physical
dimensions of the sampler also prohibit its
deployment in wells having diameters less than 4
inches. Based on these considerations the
Multiprobe 100 is judged to have limited
versatility as a groundwater sampling device. As
noted elsewhere in this report, only the sample
collection component of this sampling system
were evaluated in this test. Further evaluation of
the Multiprobe 100 sampler in combination with
the automated VOC analysis module are warranted
in order to assess the performance of the overall
system.
Deployment Logistics
The following observations were made during
testing of the Multiprobe 100 at both the standpipe
and groundwater monitoring wells.
• Two people were required to configure,
install, and operate the sampler. Although the
sampler is designed for permanent installation
and automatic sampling at timed intervals
using a microprocessor/controller, in this test
the automation module was configured for
manual control. The ease of programming the
controller for automated sampling was not
determined in this test. Permanent installation
of the overall system would probably be best
accomplished by Burge Environmental
personnel; however, user installation could be
done following some training by Burge
personnel.
• The system was configured in a temporary
arrangement for this ETV test, with many of
the system parts unenclosed. Enclosures were
not used since the unit was moved to several
different well locations during the test. The
interconnections between the sampling and
collection reservoirs included wire cables,
insulated electrical wires, and narrow-diameter
tubing that was not integrated into a single
conduit. A permanent deployment of system
components at the wellhead would require
secure, weather tight enclosures that would be
assembled by the supplier to meet local
requirements.
• The sampler requires a source of compressed
nitrogen at the wellhead.
• The equipment is self-contained and requires
no external power to operate.
• The entire system is designed for dedicated
use in unattended sampling at groundwater
monitoring wells. The sampler can be
complemented with an onsite, automated,
analysis module for TCE and other
halogenated VOCs. However, these
components were not evaluated in this test
program.
• The sampler's only moving parts are a number
of electrical solenoid valves whose long-term
performance in a high-humidity environment
was not evaluated in this test.
• The sampler can be equipped with up to eight
inlet lines so that samples can be collected at
multiple levels using a single sampling unit.
Performance Summary
Multiprobe 100 performance is summarized in
Table 7. Categories include precision,
comparability with reference method, versatility,
and logistical requirements. Cost and physical
characteristics of the equipment are also included.
The results of this verification test show that the
Multiprobe 100 performed in a comparable
manner to a reference method with regard to
21
-------
precision. Absolute comparisons between
Multiprobe 100 and reference samples reveal a
general trend toward a negative bias in terms of
Multiprobe 100 recovery for 11DCE, TCE and
particularly PCE. Multiprobe 100 recoveries for
the other three target VOC compounds, on
average, were closer to zero bias.
The Multiprobe 100 unit is a component of an
overall automated sampling and analysis system.
This evaluation concentrated on understanding the
performance characteristics of the sampling
module only. An evaluation of the entire system is
warranted in order to assess the overall system
performance.
Table 7. Performance Summary for Multiprobe 100
Performance
Parameter
Summary
Precision
For 6 target compounds at low (-20 ^g/L) and high (-200 ^g/L) VOC
concentrations and sampling depths of 17, 35, 53, and 91 feet:
Relative standard deviation range: 3.0 to 21.1% (reference: 2.0 to 17.4%)
Median relative standard deviation: 9.4% (reference: 8.6%)
In 46 of 48 standpipe test cases, Multiprobe 100 precision was statistically
comparable to reference sampler precision.
Comparability with
reference samples
For 6 target compounds at low (-20 ^g/L) and high (-200 ^g/L) VOC
concentrations and sampling depths of 17, 35, 53 and 91 feet:
Percent difference range: -30 to 15%
Median percent difference: -5%
In 31 of 48 test cases, Multiprobe 100 differences relative to reference
samples were statistically indistinguishable from 0%. In 16 of the remaining
17 cases sampler differences were statistically significant and less than 0%.
Sampler versatility
The Multiprobe 100 is judged to have limited versatility for groundwater
monitoring operations. The sampler's physical dimension prevents
deployment wells with diameters less than 4 inches. The observed negative
biases of the Multiprobe 100 for 11DCE, TCE and PCE may require further
evaluation prior to routine monitoring applications for these compounds.
Logistical requirements
System is designed for permanent installation and would be best installed by
the vendor although several days of training would enable user installation.
System requires a source of compressed air or nitrogen at the wellhead.
Periodic maintenance requirements associated with long-term unattended use
were not evaluated in this test.
Completeness
System was successfully used to collect all of the samples prescribed in the
verification test plan.
Purchase cost
Complete sampler: $3,000 per well (does not include automated VOC
analysis or installation costs.)
Size and weight
Sampling module: 3.25-inch dia. x 18-inch length, 3 pounds
Receiver module: 3.25-inch dia. x 12-inch length, 3 pounds
Microprocessor Controller: 10x4x4 inches, 5 pounds
Other
System is designed for low-volume purge applications.
System is designed for use in unattended, automated well-sampling programs
when combined with onsite, real-time analyzers for TCE and other chlorinated
organics.
Note: Target compounds were 1
1,1,2-trichloroethane (112TCA),
,1-dichloroethene (11DCE), 1,2-dichloroethane (12DCA), benzene (BNZ), trichloroethene (TCE),
and tetrachloroethene (PCE).
22
-------
Section 5 — Multiprobe 100 Technology Update
and Representative Applications
Note: The following comments were provided by
the vendor and were edited only for editorial
consistency with the rest of the report.
The Multiprobe 100 sampling system is capable of
creating a headspace over a volume of water while
under the static water level of the well. This
design feature allows various sensors to be placed
within a monitoring well without being immersed
in water. Alternatively, the sensors can be placed
at the top of the well casing or in specially
designed, environmentally controlled boxes
adjacent to the monitoring wells. A calibration
module is available which allows the sensors to be
calibrated while positioned inside the monitoring
well.
The Multiprobe 100 sampling unit is designed for
multi-level sampling in 4-inch wells. The probe is
designed to transport the analyte of interest from
the collection point in either the groundwater or as
a component in an inert gas phase following its
being purged from the groundwater sample.
Following its transport to the surface by the
sampling system, the analyte can be introduced
into sample containers (VOA vials, sorptive tubes)
for transport to a laboratory or it can be analyzed
onsite through exposure to various sensors located
either in the well or at the wellhead. The primary
purpose of the Multiprobe 100 is to provide an
interface from groundwater to onsite chemical
sensing systems. The flexibility built into the
Multiprobe 100 that enables one to select the type
of transport media (liquid or gas phase) makes this
system unique among the sampling systems
presently on the market. A totally integrated
multi-level groundwater sampling system, as
shown in Figure 8, that is interfaced with a
chemical sensing system, shown in more detail in
Figure 9, allows for the automation of
groundwater monitoring and analysis. The errors
associated with groundwater monitoring
(including the errors observed in this
demonstration) can be reduced by automating the
sampling and analysis under controlled conditions.
The control of errors coupled with the cost savings
of automating long-term monitoring may be a
significant advantage to this technology. The
automation of groundwater sampling and analysis
allows sampling to be conducted more frequently
than quarterly and it provides near real-time
collection and reporting of data from an aquifer.
This can be an advantage during remedial action
monitoring or the monitoring of possible
breakthrough of contaminants at barrier walls.
Other advantages of an automated system include
the communication of onsite real-time data to a
web page or similar format for uncomplicated
access by regulators and/or the public.
23
-------
Mtroficn
KccciviRij
Rij MiiJj.f
VwHICaiing-
Sampling MoiitiTe
Tuhing w Col led
Miilli-U-vsl Si
II1
Cablini Will
EJeilric, Walur
Nilrii^l LilHS^
tifiKjnil-HVuicT L^%!t;l
Figure 8. A schematic diagram of the Multiprobe 100 interfaced to
an onsite analysis module.
24
-------
Electrical
Wires
Nitrogen
Line
Water]
Line
Controller^
Board"
I
Waste Reagent
Bottle Bottle
Source/Receiver
, Circuits ,
Source! j] Receiver
UJ/Optrode
Sample
Chamber
Reagen
Pump
L
Stirring
Motor I
Water
Valve
Figure 9. A schematic diagram of an automated analysis
module for TCE
25
-------
26
-------
Section 6 — References
EPA, 1996. "Test Methods of Evaluating Solid Waste: Physical Chemical Methods; Third Edition; Final
Update III," Report No. EPA SW-846.3-3, Government Printing Office Order No. 955-001-00000-1, Office
of Solid Waste and Emergency Response, Washington, DC.
EPA, 1998. Environmental Technology Verification Report, Field Portable GC-MS, Inficon HAPSITE;
Report Number EPA/600/R-98/142, US EPA, Office of Research and Development, Washington, DC. (also
available at http://www.epa.gov/etv/verifipt.htnrf02).
Foster Wheeler, 1998. "Final Hydrogeologic Investigation Report for the National Aeronautics and Space
Administration Stennis Space Center, Mississippi," Office of Environmental Engineering, NASA, Stennis
Space Center, Mississippi, 39529.
Havlicek, L.L, and R D. Grain, 1988a, Practical Statistics for the Physical Sciences, pp 202-204. American
Chemical Society, Washington, DC.
Havlicek, L.L, and R. D. Grain, 1988b, Practical Statistics for the Physical Sciences, pp 191-194. American
Chemical Society, Washington, DC.
NIST, 2000. National Institutes of Standards and Technology, Standard Reference Database No. 69, R.
Sander, editor, available at http://webbook.nist.gov/chemistry.
Puls, R.W., and Barcelona, M. J., 1996, Low-Flow (Minimal Drawdown) Ground-Water Sampling
Procedures, US EPA Ground Water Issue (April 1996), Publication No. EPA/540/S-95/504, US EPA Office
Solid Waste and Emergency Response, Washington, DC.
Sandia, 1999. Groundwater Sampling Technologies Verification Test Plan, Sandia National Laboratories,
Albuquerque, NM 87185 (also available at http://www.epa.gov/etv/test jlan.hta#monitoring).
27
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28
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Appendix A — Quality Summary for Analytical Method
Introduction
An onsite GC/MS-headspace method was chosen for analysis of all samples in this study. Two identical
GC/MS systems were operated by Field Portable Analytical (Folsom, CA) using a modified EPA Method
8260 (for a summary of the method, see Section 3). Data quality measures were incorporated into all onsite
analyses consistent with the guidelines in Method 8260. This appendix summarizes those data quality
measures, thereby demonstrating the adequacy of the method for this verification study.
Data Quality Measures
A number of data quality measures were used to verify acceptable instrument performance and the adequacy
of the final analytical results throughout the course of the study. These measures are summarized in Table A-
1. All data quality measures in this table were followed, with the exception of duplicates. Duplicates were
not routinely run since all of the samples from the field were in batches of replicates. Earlier
predemonstration studies indicated that the field replicates were the same in composition so that they could be
treated as analysis duplicates.
Table A-l. Onsite GC/MS-Headspace Method Quality Control Measures
Quality Control
Check
MS tune check w/
bromofluorobenzene
(BFB)
5-Point (Minimum)
calibration
Continuing calibration
check (CCC)
End calibration
checks
Duplicates
Method blanks
Minimum
Frequency
Every 12 hours
Beginning of each day
Beginning of each day
End of each day
10% of the samples
After beginning of day
CCC
Acceptance
Criteria
Ion abundance criteria
as described in EPA
Method TO-1 4
%RSD < 30%
± 25% difference of
the expected
concentration
for the CCC
compounds
±25% RPDofthe
beginning CCC
Relative percent
difference < 30%
Concentrations for all
calibrated compounds
< practical
quantification level
Corrective
Action
1) Reanalyze BFB
2) Adjust tune until
BFB meets
criteria
Rerun levels that do
not meet criteria
1) Repeat analysis
2) Prepare and run
new standard
from stock
3) Recalibrate
1) Repeat analysis
2) If end check is
out, flag data
for that day
1) Analyze a third
aliquot
2) Flag reported
data
Rerun blanks until
criteria are met
Data Quality Examples
The following data are examples of system performance throughout the course of the study. In the interest of
brevity, all quality control data are not shown in this appendix. A complete tabulation of all quality control
data is included in the GW SAMPLING DATA NOTEBOOK and is available for viewing through a request
to the ETV Site Characterization and Monitoring Technologies Pilot Manager.
29
-------
Method Blank Check
Method blanks were run at the beginning of each 12-hour analysis session. Concentration levels of the six
target compounds were reported as ND <5 |jg/L for all method blank samples.
Continuing Calibration Check
The method criterion for the continuing calibration checks run at the beginning and end of each analysis cycle
was a value within 25% of the expected value. The results of the TCE continuing calibration checks for both
of the GC/MS instruments used in the study are shown in Figures A-l and A-2. Similarly, the results of the
PCE continuing calibration check for both instruments are shown in Figures A-3 and A-4. All check
compound recoveries fall within the predefined control interval of 70 to 130%. The control interval is
specified in EPA Method SW-846, from which this method is adapted. The relative percent differences
between the pre- and post-analysis batch calibration check samples are shown in Figure A-5. In two cases,
the relative percent difference falls outside the 25% window. Data from these days were not rejected,
however, since the +30% criteria for the calibration check was met.
GCMS (Pepe) Control Chart
TCE Check Standard
130
& 110
Upper Control Limit
Lower Control Limit
8/10/99 8/11/99 8/12/99 8/13/99 8/14/99 8/15/99 8/16/99 8/17/99
Day
Figure A-l. Calibration check control chart for TCE on GC/MS #1.
30
-------
GCMS (Taz) Control Chart
TCE Check Standard
130
120
110
100
Upper Control Limit
S
in
Lower Control Limit
8/9/99 8/10/99 8/11/99 8/12/99 8/13/99 8/14/99 8/15/99 8/16/99 8/17/99
Day
Figure A-2. Calibration check control chart for TCE on GC/MS #2.
GCMS (Pepe) Control Chart
PCE Check Standard
130 -
Check Standard Recovery, %
3> ^1 OJ CD 0 -^
D O O O ° °
Upper Control Limit
4Se
• Se
riesl
ries2
* * * 1 * *
• H " "
•
• •i
™
Lower Control Limit
. ..A.. .
8/10/99 8/11/99 8/12/99 8/13/99 8/14/99 8/15/99 8/16/99 8/17/99
Day
Figure A-3. Calibration check control chart for PCE on GC/MS #1.
31
-------
GCMS (Taz) Control Chart
140
ss
> 110
Upper Control Limit
Lower Control Limit
8/9/99 8/10/99 8/11/99 8/12/99 8/13/99 8/14/99 8/15/99 8/16/99 8/17/99
Day
Figure A-4. Calibration check control chart for PCE on GC/MS #2.
GC/MS (Pepe and Taz) System Check
Relative Percent Difference -Daily Begin/End Check
@Pepe~TCE
OPepe-PCE
4U QTar-TCE
QTaz-PCE
.£ JO
b
20
I
iS
Amaiysis Date
Figure A-5. GC/MS system check relative percent differences.
32
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