United States Office of Research and EPA/600/R -00/054
Environmental Protection Development June 2000
Agency Washington, D.C. 20460
Environmental Technology
Verification Report
Groundwater Sampling
Technologies
Sibak Industries Ltd. Inc.
Kabis Sampler
Models I and II
Sandia
National
Laboratories
ETV ETV ET
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EPA/600/R-00/054
June 2000
Environmental Technology
Verification Report
Groundwater Sampling
Technologies
Sibak Industries Ltd. Inc.
Kabis Sampler
Models I and II
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
Sandia
National
Laboratories
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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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THE ENVIRONMENTAL TECHNOLOGY VERIFICATION
PROGRAM,
Sandia
National .
Laboratories
ETV JOINT VERIFICATION STATEMENT
TECHNOLOGY TYPE: GROUNDWATER SAMPLING TECHNOLOGIES
APPLICATION: VOC-CONTAMINATED WATER SAMPLING
TECHNOLOGY NAME: Kabis Sampler, Models I and II
COMPANY: Sibak Industries Ltd. Inc.
ADDRESS: P.O. Box 86 PHONE: (800) 794-6244
Solana Beach, CA 92075 (858) 793-6713
WEBSITE: www.sibak.com FAX: (619)793-6713
EMAIL: sibak@sibak.com
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 Kabis Model I and II
discrete-level point samplers.
EPA-VS-SCM-39 The accompanying notice is an integral part of this verification statement. June 2000
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DEMONSTRATION DESCRIPTION
In August 1999, the performance of six groundwater sampling devices was evaluated at the US
Geological Survey (USGS) Hydrological Instrumentation Facility at the National Aeronautics and Space
Administration (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 "aboveground" well, was filled with water spiked with various
concentration levels of six target volatile organic compounds. The target compounds (1,2-
dichloroethane, 1,1-dichloroethene, trichloroethene (TCE), 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 |J,g/L) concentrations of the six target VOC compounds in
water at sampler depths ranging from 17 to 91 feet. A blank sampling trial and an optional "clean-
through-dirty" trial were also included in the test matrix. The "clean-through-dirty" test was included to
investigate the potential of contaminant carryover as a sampler is lowered through a "dirty" (high VOC
concentration) layer of water in order to sample an underlying "clean" (low VOC concentration) layer.
The standpipe trials were supplemented with sampler deployments at groundwater monitoring wells in
the vicinity of VOC-contaminated groundwater at the NASA Stennis facility. The Kabis sampling
device was deployed in a number of 2-inch and 4-inch wells. Comparison samples were also collected
using a submersible electric gear pump. The principal contaminant in the monitoring wells was
trichloroethene. The groundwater monitoring test phase provided an opportunity to observe the
operation of the sampling device under typical field-use conditions.
All technology and reference samples were analyzed by the same field-portable gas chromatograph-mass
spectrometer (GC/MS) system that was 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, with the use of a
headspace sampler in lieu of a purge-and-trap unit. The overall performance of the groundwater
sampling technologies was assessed by comparison of technology and reference sample results with
particular attention given to key performance parameters such as sampler precision and accuracy.
Aspects of field deployment and potential applications of the technology were also considered.
Details of the demonstration, including an evaluation of the sampler's performance, may be found in the
report entitled Environmental Technology Verification Report: SibakIndustries Ltd. Inc., Kabis Sampler,
EPA/600/R-00/054
TECHNOLOGY DESCRIPTION
The Kabis Sampler is a discrete-level, grab sampler. The two models evaluated in this test operate on the
same principle and only differ in size and sampling capacity. Both samplers are constructed of 321
stainless steel. The Model I is 17.4 inches long, 1.75 inches in diameter, and weighs 6.5 pounds. The
Model II is 22.3 inches long, 3.65 inches in diameter and weighs 15.5 pounds. Both samplers have a
removable top into which a single (Model I) or three (Model II) 40-mL VOA vial(s) are screwed prior to
sampler deployment in the well. The sampler is attached to a measuring tape and is manually lowered into
the water column. The size and orientation of the inlet and exhaust ports of the sampler are such that it
does not fill while it is being lowered down through the water column in the well. When the sampler is
held stationary at the desired sampling depth, it begins to fill under hydrostatic pressure. Fill duration time
is about 5 minutes for the Model I and 8 minutes for the Model II.
EPA-VS-SCM-39 The accompanying notice is an integral part of this verification statement. June 2000
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Air inside the sampler escapes through an exhaust port as the installed sample vials fill from the bottom
upward. The vials are flushed with about 6 vial volumes prior to the collection of the final vial volume
at the end of the sampling cycle. The flush water flowing through the vials spills into the sampler body
through spill ports located in the vial holder in the sampler head. Following completion of the fill cycle,
the sampler is manually retrieved to the surface and the sample vials removed. The sample is then
preserved, if required, and the vials are capped with positive-displacement-type caps that ensure a
bubble-free sample. Sampler decontamination is carried out by rinsing the sampler in the field using a 5-
gallon bucket of detergent water followed by several deionized or distilled water rinses.
Costs for the Kabis samplers are $825 for the Model I and $1,895 for the Model II. Additional sampler
accessories available include a delivery tape, wooden storage box, and positive-displacement VOA vial
caps.
The Model I and Model II samplers differ only in their size and number of vials filled during sampling.
The samplers were used interchangeably in the study and their performance results are combined.
Hereafter, the two sampler models are simply referred to as the Kabis sampler.
VERIFICATION OF PERFORMANCE
The following performance characteristics of the Kabis sampler were observed:
Precision: The precision of the sampler was determined through the collection of a series of replicate
samples from four standpipe trials using low (-20 |Jg/L) and high (-200 |J,g/L) VOC concentrations at
17-foot and 91-foot collection depths. Each trial included 6 target VOCs for a total of 24 cases. Kabis
sampler precision, represented by the relative standard deviation, for all compounds at all concentrations
and sampling depths evaluated in this study, ranged from 2.9 to 25.8%, with a median value of 10.7%.
Reference method precision ranged from 4.1 to 17.6%, with a median relative standard deviation value
of 8.7%. In 16 cases, the relative standard deviation of the Kabis samples was greater than the reference
samples, with Kabis precision less than or equal to reference sample precision in the other 8 cases. The
F-ratio test was used to assess whether the observed precision differences between Kabis and reference
samples were statistically significant. Test results showed that precision differences between Kabis and
reference were statistically insignificant at the 95% confidence level in 23 of the 24 cases.
Comparability with a Reference: Kabis sampler results from the standpipe trials were compared with
results obtained from reference samples that were collected at the same time. Both Kabis and reference
samples were analyzed by the same analytical 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 used in this study ranged from -39 to
18%, with a median difference of -3%. The t-test for two sample means was used to assess whether the
observed differences in Kabis sampler and reference sample results were statistically significant. These
tests revealed that in 16 of 24 trials, the differences were not statistically different at the 95% confidence
level. Of the remaining 8 cases, 5 showed a statistically significant Kabis sampler negative bias; and in 2
of those cases, the negative bias for PCE was in excess of 25%.
Versatility: Sampler versatility is the consistency with which the sampler performed over the ranges of
target-compound volatility, concentration levels, and sampling depths. The standpipe tests reveal
generally consistent performance with regard to Kabis sampler precision. Kabis sampler results show
low recovery for TCE and PCE at the higher (-200 |J,g/L) concentration at the deeper (91 ft) sampling
location used in this evaluation. In light of these results, the Kabis sampler is judged to have limited
versatility.
Logistical Requirements: The sampler can be deployed and operated in the field by one person. About
1 hour of training is generally adequate to become proficient in the use of the system. The sampler is
EPA-VS-SCM-39 The accompanying notice is an integral part of this verification statement. June 2000
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compact and can easily be hand carried to the wellhead for use. Decontamination of the sampler can be
carried out in the field by using a detergent water rinse followed by several distilled water rinses. A
reasonable degree of manual dexterity is required to remove the sample vials from the sampler head
without sample loss. Sampling vials that have been pre-preserved cannot be used in this sampler.
Preservative must be added following sample collection, if required.
Overall Evaluation: The results of this verification test show that the Kabis sampler can be used to
collect VOC-contaminated water samples that are generally indistinguishable from a reference method
with regard to precision. Sampler recovery, relative to reference samples, was acceptable for four of the
six target compounds. Test results indicated low sample recovery with the Kabis sampler for TCE and
PCE at high concentrations at both shallow and deep sampling locations.
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. 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-39
The accompanying notice is an integral part of this verification statement.
June 2000
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Table of Contents
List of Figures iii
List of Tables v
Acknowledgments vii
List of Abbreviations and Acronyms ix
1 INTRODUCTION 1
Background 1
Demonstration Overview 1
2 TECHNOLOGY DESCRIPTION: KABIS SAMPLER 3
3 DEMONSTRATION PROCESS AND DESIGN 5
Introduction 5
Site Description 5
Verification Test Design Summary 7
Test Design Elements 7
Sampler Performance Parameters 9
Sample Analysis 10
Data Processing 10
Data Quality Control 10
Verification Test Plan 11
Standpipe and GW Well-Sampling Matrix 11
Chronological Summary of Demonstration Activities 12
Deviations from the Verification Plan 13
4 PERFORMANCE EVALUATION FOR KABIS SAMPLER 15
Introduction 15
Sampler Precision 15
Comparability to Reference 15
Blank and Clean-through-Dirty Performance 18
Monitoring Well Results 18
Sampler Versatility 19
Deployment Logistics 19
Performance Summary 19
5 KABIS SAMPLER TECHNOLOGY UPDATE AND REPRESENTATIVE APPLICATIONS 21
Vendor Observations on Clean-Through-Dirty Sampling 21
Example Field Applications 21
6 REFERENCES 23
APPENDICES
A: REFERENCE PUMP PERFORMANCE 25
B: QUALITY SUMMARY FOR ANALYTICAL METHOD 29
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List of Figures
1 Kabis sampler Model I (right) and Model II (left) 3
2 Illustration of the Kabis sampler filling sequence 3
3 The standpipe attheUSGS Hydrological Instrumentation Facility 6
4 Kabis sampler comparability with reference samples from the standpipe trials 17
A-l Percent recoveries of the reference pump by compound for the four standpipe trials 28
B-l Calibration check control chart for TCE on GC/MS#1 30
B-2 Calibration check control chart for TCE on GC/MS#2 31
B-3 Calibration check control chart for PCE on GC/MS#1 31
B-4 Calibration check control chart for PCE on GC/MS#2 32
B-5 GC/MS system check relative percent differences 32
ill
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IV
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List of Tables
1 Construction Details of Groundwater Monitoring Wells 7
2 Target VOC compounds 7
3 Sampler Verification Trials at the Standpipe 12
4 Sampler Verification Trials at the Groundwater Monitoring Wells 13
5 Precision Summary forKabis and Reference Sample 16
6 Comparability of Kabis and Reference Sample Data from Standpipe Trials 17
7 Clean-through-dirty Test Results for the Kabis Sampler 18
8 Kabis Sampler and Reference Pump Results from Groundwater Monitoring Wells 19
9 Performance Summary forKabis Sampler 20
A-l Precision of Gear Pump and Reference Samples in Standpipe Trials 26
A-2 Comparability of the Gear Pump with the Reference Samples in Standpipe Trials 27
B-l Onsite GC/MS-Headspace Method Quality Control Measures 29
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VI
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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 technical assistance 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 Greenfield (Field Portable Analytical)
for their care and diligence in sample analysis during the field trials.
For more information on the Groundwater Sampling Technology Verification Test, contact:
Eric Koglin Wayne Einfeld
Project Technical Leader ETV Project Manager
Environmental Protection Agency Sandia National Laboratories
Environmental Sciences Division MS-0755 PO Box 5800
National Exposure Research Laboratory Albuquerque, NM 87185-0755
P. O. Box 93478 (505) 845-8314 (v)
Las Vegas, Nevada 89193-3478 E-mail: weinfel@sandia.gov
(702) 798-2432 (v)
E-mail: koglin.eric@epamail.epa.gov
For more information on the Kabis Samplers contact:
Thomas (Tom) W. Kabis
Sibak Industries Limited Inc.
P.O. Box 86
Solana Beach, CA 92075
800-794-6244 or (858) 793-6713 (v)
e-mail: sibak@sibak.com
tkabis@jps.net
vn
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Vlll
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List of Abbreviations and Acronyms
BNZ
DIFF
EPA
ETV
GC/MS
fflF
MSL
MW
NASA
ND
NERL
PCE
PTFE
PVC
QA
QC
REF
RSD
SCMT
SNL
SP
SSC
TCE
USGS
VGA
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 (perchloroethene)
Polytetrafluoroethylene
Polyvinyl chloride
Quality assurance
Quality control
Reference
Relative standard deviation
Site Characterization and Monitoring Pilot
Sandia National Laboratories
Sample port
Stennis Space Center
Trichloroethene
US Geological Survey
Volatile organics analysis
Volatile organic compound
1,2-dichloroethane
1,1 -dichloroethene
1,1,2-trichloroethane
IX
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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 Technology
(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 systems: Multiprobe 100
(Burge Environmental, Tempe, AZ), SamplEase
(Clean Environment Equipment, Oakland, CA)
Micro-Flo (Geolog Inc., Medina, NY), Well
Wizard (QED Environmental, Ann Arbor, MI),
Kabis Sampler (Sibak Industries, Solana Beach,
CA), GoreSorber (W. L. Gore and Associates,
Elkton, MD), and the Kabis Sampler. This report
contains an evaluation of the Kabis Sampler,
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Models I and II, manufactured by Sibak Industries
Ltd., Solano Beach, CA.
It is important to point out that the scope of this
technology demonstration was purposely limited
to sampling device performance parameters such
as precision, comparability to a reference
measurement, and where applicable, deployment
logistics. Several of the systems tested in this
study are intended for use with low-flow 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 did not evaluate the merits of a
low-flow purge 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 Aeronautics and Space
Administration (NASA) Stennis Space Center
(SSC) 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 (VOC). 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.
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
technologies were deployed in a number of 2-inch
and 4-inch wells, along with the reference
samplers for comparison. 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 comparing
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 to
reference sample results. Aspects of field
deployment and potential applications of the
technology were also considered.
A brief outline of this report is as follows: Section
2 contains a brief description of the Kabis 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 Kabis sampler
technology and provides examples of potential
applications of the sampler in site characterization
and monitoring situations. Appendix A contains
performance data for the reference pump, and
Appendix B presents an assessment of quality
control data associated with the analytical method
used in this study.
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Section 2 — Technology Description: Kabis Sampler
This section provides a general description and
overview of the capabilities of the Kabis sampler
Models I and II manufactured by Sibak Industries.
The information used to prepare this section was
provided by Sibak Industries.
Two Kabis samplers, the Model I and Model II, as
shown in Figure 1, were evaluated in this test.
They operate on the same principle and only differ
in size and sample capacity. The Model I is 17.4
inch long with a 1.75-inch external diameter and a
weight of 6.5 pounds. The Model II is 22.3 inches
long with a 3.55-inch external diameter and a
weight of 15.5 pounds. Both samplers are
constructed of 321 stainless steel and have a
removable top into which a single (Model I) or
three (Model II) 40-mL volatile organic analysis
(VOA) vials are screwed prior to sampler
deployment in the well. The sampler is attached to
a measuring tape and slowly lowered into the water
column. The orientation of the inlet and exhaust
ports of the sampler is such that the sampling
chamber does not fill while it is being lowered
down through the water column. When the sampler
is held stationary at the desired sampling depth, it
begins to fill by hydrostatic pressure. Fill time is
about 5 minutes for the Model I and 8 minutes for
the Model II.
The Kabis sampler employs simple physics for its
operation. As illustrated in Figure 2, water surface
tension across the exhaust port (Ti) is equal to the
water surface tension across the fill port (T2). The
head pressure (h) imposed by the vertical
difference between the fill port (Pi) and the
exhaust port (P2) is only slightly greater than the
surface tension across both the fill and exhaust
ports. As the sampler is lowered past the air/water
interface and down through the water column, the
hydrostatic pressure (P) changes across both the
fill and exhaust ports at a constant rate. As the
hydrostatic head pressure increases, the imposed
head pressure (h) tends toward the asymptote of
zero. Since h approaches zero, the water surface
tension prevents water entry into either sampler
port. As the sampler descent rate goes to zero at
the desired sampling depth, the imposed head
pressure is restored and slowly overcomes the
surface tension at the fill port, and the fill cycle
begins.
Air inside the sampler escapes through the exhaust
port and the installed sample vial(s) fills from the
bottom of the vial upward. The vial(s) are flushed
with a total of about 6 vial volumes prior to
collection of the final vial volume. The flush
Outlet (air) port
Inlet (water) port
T2/ P,
Figure 1. Kabis sampler Model I (right) and
Model II (left).
3. APt:h +0
-40-mL VOA vial
Figure 2. Illustration of the Kabis sampler
filling sequence.
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water flowing through the vial spills into the
sampler body through spill ports located in the vial
holder on the sampler head. When the overflow
water in the sampler body reaches the bottom of
the exhaust port, no more air can escape from the
sampler body and the sampler fill cycle is
complete. The sampler is then retrieved to the
surface. The sampling head is unscrewed from the
body of the sampler and the sample vials are then
removed from the sample head. If sample
preservation is required, few drops of preservative
solution can be added. The vial is then capped
with a positive-displacement-type cap that ensures
a bubble-free sample.
The Kabis sampler is designed to collect a sample
from a well at a specific depth chosen by the
sampler operator. It is a grab sampler and by virtue
of this fact does not incorporate well purging in its
use. Well purging, whether by a low-flow method
or traditional three-volume purge, may or may not
be required in monitoring applications. If site
sampling objectives require well purging, other
devices could be used to carry out well purging
prior to the use of a Kabis unit for sample
collection.
The sampler has no moving parts and requires no
maintenance other than routine decontamination.
Decontamination procedures consist of a detergent
water rinse followed by several distilled water
rinses and can be easily carried out in the field.
Costs for the two Kabis samplers are $825 for the
Model I and $1,895 for the Model II. Sampler
accessories, not included in the base price, include a
delivery tape, wooden storage box, and positive-
displacement VOA vial caps.
Additional information on potential applications of
the system for environmental characterization and
monitoring can be found in Section 5—Technology
Updates and Application.
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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 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. TheHydrologic
Instrumentation Facility supports USGS
agencywide 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 1. The Standpipe is
an aboveground, 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
mixing and transfer of solution. 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 technology samples inside the
pipe. As shown in Figure 1, the indoor facility has
six levels of access, including the ground floor,
and all levels are serviced by a freight elevator. 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 known as Upper Clay, and found
at elevations ranging from 10 to 30 feet mean sea
level (MSL), overlying a sandy unit named Upper
Sand (at 5 to 15 feet 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 interbedded 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.
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
poly vinyl chloride (PVC) pipe with a 10-foot PVC
-------
5 IN. DIA.-
SPIf
5P13
SP12 I*
SP11
SP10
SPS.
SPS r*
SP7
SPS
SPS
5P4
3P2
LEVEL 5
-1 IN, DIA. FILL/OfiAIN LIME
LEVEL 4
LEVEL 3
SP - SAMPLING PORT
SP DISTANCE FROM TOP WADER LEVEL
SP13 17.S Ft.
SP9 54 ft.
SP7 64 ft.
SP4 82 ft.
5P2 92 Ft.
LEVEL 2
/EXIT LINE
Figure 3. The standpipe at the USGS Hydrological Instrumentation Facility.
-------
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. The depth of the water column
above the midscreen 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 sampler performance parameters such as
precision and comparability with reference to be
evaluated. 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 andpassive samplers, with individual
sampling trials designed specifically for these two
categories.
Target VOC Compounds—Six target compounds,
all regulated under the 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
Dia.
(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.
7
-------
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).
Spike solutions of all six target compounds were
prepared in methanol from neat compounds. 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 Sample—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 had external sampling ports
along its length so that reference samples could be
collected simultaneously with the samples from
the interior of the pipe with devices 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. The use of multiple sequentially collected
samples 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 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 in which 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 could be a 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 from the overlying contaminated
layers in the well.
Groundwater Well Reference Samples—Six onsite
groundwater monitoring wells were selected for
use in the second phase of the study. A
submersible electric gear pump (Fultz, Model SP-
300) was chosen as a reference sampling device
for these additional field tests. Verification studies
on the performance of this pump were carried out
during the standpipe phase of the experiments to
provide technical data substantiating its use as a
reference method in the field. A more complete
description of the pump along with a summary of
these data is given in Appendix A. During field
sampling events, the reference pump was co-
located in the well with the sampling devices in
order to provide simultaneous reference samples
from the well. Teflon tubing ('/t-inch outside
diameter) was used to transport the water sample
from the pump outlet to the collection vial at the
wellhead. During all sampling, the pump was
operated at a low flow rate (100-200 mL/min).
During Kabis sampler testing in groundwater
monitoring wells, the reference pump and the
Kabis sampler could not be simultaneously
deployed in the well as a result of space
limitations. In these instances, the Kabis sampler
was deployed first and replicate samples were
collected. Following Kabis sample collection, the
reference pump was immediately deployed and a
second set of reference samples was collected.
As noted previously, the field sampling trials were
not an evaluation of the low-flow purge
methodology for well sampling. Consequently,
water quality parameters were not monitored in
the field sampling trials. The presampling purge
was used to flush the reference pump and tubing to
ensure that the pump was drawing from the well
column water. Whether formation water was
-------
being sampled was of secondary importance in
this sampling plan.
Sampler Performance Parameters
Four performance parameters were evaluated in
the assessment of each technology. 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 (RSD) 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=
100
Here, X, 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 the assessment of sampler
precision, a statistical test was used to assess
whether differences between the reference sample
precision and the technology sample precision
were statistically significant. Specifically, the F-
ratio test was used to compare 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 the
spike mixtures were mixed and transported 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 XteA the average reported concentration
of all technology sample replicates and X^f is the
average reported concentration of all reference
sample replicates. The t-test for two sample
means was used to assess 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 methods.
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 encountered in both the standpipe and the
groundwater monitoring well 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 or at some of the tested
sampling depths.
Field Deployment Logistics — This final 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
training, ancillary equipment requirements, and
field portability.
-------
Operator Influence—The sampling technician as
well as the sample collection method have 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 sample flow rate when filling the vial with a
bladder pump, the cycle times and volume of
bladder pump and others may influence overall
sample quality. An evaluation of operator
influence on sample quality is beyond the scope of
this study. All operators were experienced in the
use of their technologies and the assumption is
made that these operators were operating their
sampling devices 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 an 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].
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 VOCs in water analysis were
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-mL 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 immediately transferred to a 50-mL
glass syringe. Half (20 mL) of the sample was
then transferred to a second 40-mL 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 in 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 subsequent 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 the internal standard
method (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 has
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—All sampling activities
were documented by Sandia National Laboratories
(SNL) field technicians using chain-of-custody
10
-------
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.
Predemonstration Analytical System Audit—Prior
to the actual demonstration, a number of samples
containing the six target compounds at various
concentration levels were prepared at SNL and
sent via overnight Express Mail in an ice pack to
Field Portable Analytical near Sacremento, CA.
They were analyzed by GC/MS analysis 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 B.
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
accepted 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 and GW Well-Sampling
Matrix
The sampling matrix for the standpipe sampling
phase of the demonstration is given in Table 3.
All standpipe and groundwater well testing was
carried out sequentially, with the various
participants deploying their technologies 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
included seven trials. Trials 1 and 2 were carried
out at shallow and deep locations with the a low
concentration (10-20 |Jg/L) standpipe mixture.
Trials 3 and 4 were conducted at shallow and deep
locations with a high-concentration (175-225
|jg/L) standpipe mixture. In all trials, reference
samples were collected from external sampling
ports simultaneously with sample collection by the
device under test.
Trial 5 was a blank mixture measurement at the
standpipe to test the cleanliness of each sampler.
For this trial, the standpipe was filled with tap
water and three replicates were collected by the
device under test from the deep location in the
pipe while three reference replicates were
collected simultaneously from the adjacent
exterior sampling port.
Trials 6 and 7 at the standpipe were termed "clean-
through-dirty" tests and were designed to evaluate
the discrete-level sampling performance of the
Kabis sampler. This test was optional for the other
11
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Table 3. Sampler Verification Trials at the Standpipe
Trial No.
1
2
3
4
5
6
7
Standpipe
Collection
Port
SP14
SP3
SP14
SP3
SP3
SP3
SP12
Sample
Collection
Depth (ft)
Low (17)
High (92)
Low (1 7)
High (92)
High (92)
High (92)
Low (35)
VOC Concentration
Level
Low (-20 |j,g/L)
Low (-20 |j,g/L)
High (-200 ug/L)
High (-200 pg/L)
Blank
Mixed (high over low)
Mixed (high over low)
No. of Replicates
per
Technology
5
5
5
5
3
4
4
Notes: In each trial, an equal number of reference samples were collected simultaneously with the technology samples
from adjacent external Standpipe sampling ports. Sample collection points during trials 6 and 7 were from the low VOC
concentration region after the sampler was lowered through a high VOC concentration region.
active samplers. Those sampling systems that
were intended for permanent deployment in a well
were not required to participate in the "clean-
through-dirty" sampling trials, although some
chose to participate voluntarily. In this test, two
mixtures, a high (-200 |Jg/L) and a low (-20
|jg/L), were prepared in the mixing tanks. The
pipe was then filled so that the high-level mixture
occupied the top 1/3 of the pipe while the low-
level mixture was in the bottom 2/3 of the pipe.
Water samples were collected at the bottom and
approximate midpoint of the pipe after being
lowered through the high-level mixture at the top
of the pipe. Reference samples were
simultaneously collected from the external
sampling ports in the same manner as for the
previous Standpipe trials.
The onsite groundwater sampling matrix is shown
in Table 4. Two of the wells originally scheduled
for use were dropped from the sampling matrix
because the TCE concentrations were below the
instrument detection limit. The groundwater
sampling procedure for the Kabis and reference
sampler was as follows: As a result of the limited
space available in the 2- and 4-inch diameter
wells, the Kabis sampler and reference pump
could not be deployed in the well at the same time.
A modified sampling protocol was used in which
the Kabis sampler was first delivered to the
midscreen depth and four replicate samples were
collected. In most cases, a single delivery of the
Kabis sampler to the well was used and any VOA
vials in addition to those installed on the sampler
head were filled from the overflow reservoir of the
Kabis sampler. Following Kabis sampler retrieval,
the reference pump was installed at the same
midscreen level in the well. A purge volume of
about 1 to 2 liters was drawn through the reference
pump at a flow rate between 100 to 200
mL/minute. Following this purge, four replicate
samples were collected.
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 (multilevel 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
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 the 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.
12
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Table 4. Sampler Verification Trials at the Groundwater Monitoring Wells
Trial
10
11
13
14
Well
06-20MW
06-1 1MW
06-04MW
12-09MW
Distance from
Top of Well to
Screen Mid-
point (ft)
67.7
83.1
35.1
15.0
Water Column
Depth
(ft)
59.9
69.0
9.8
5.2
Approximate
TCE Cone.
(MQ/L)
<5
500
500
20
No. of
Replicates per
Technology
4
4
4
4
Notes: Reference samples were collected using a submersible electric sampling pump that was colocated with the Kabis
sampler in 4-inch wells and after the Kabis sampler in 2-inch wells.
Well numbers 06-04 and 12-09 were 2-inch diameter wells. All other wells had 4-inch diameters.
Approximate TCE concentrations are derived from NASA contractor quarterly monitoring data. Sampling methodology
consisted of a three-well volume purge followed by sample collection with a bailer.
Trials 12 and 15 were no-detect wells and were dropped from the data set.
Sample analysis was performed in a mobile
laboratory parked near the standpipe and was
carried out 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 instrument
variability on the analysis results.
The demonstration technical team observed and
recorded the operation of each technology during
both standpipe and monitoring well trials to assist
in the assessment of logistical requirements and
ease of use of the technology. These observations
also were used to document any performance
anomalies as well as the technical skills required
for operation.
Deviations from the Verification
Plan
Under most field testing environments,
circumstances often arise that prevent a complete
execution of the test plan. A list of the deviations
from the test plan that are judged to be important
are summarized below and an assessment of the
resulting impact on the field test data set is
included.
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. No Kabis
or Kabis reference samples were lost during the
testing.
QC-FlaggedData—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 the
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
Kabis and associated reference samples in this
study.
Samples Below Quantitation Limit of
GC/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
tubing carryover contamination was determined to
13
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be the cause of the erroneous screening data. 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 most of the objective parameters
of performance, such as sampler accuracy and
precision, are derived from the standpipe data.
Questionable Sampling Procedure—In several
sampling events at both the standpipe and
monitoring wells, the Kabis sampler operator
filled some of the replicate sample vials by
pouring from the sampler sump instead of
deploying the sampler a second time into the
standpipe or well. This procedure may have
influenced the analysis results; however, since the
procedure was done infrequently, the effects on
sample quality cannot be ascertained in this study.
Filling sample vials from the sump is not a
recommended practice in normal sampler use.
Unverified Performance Claim—One of the
performance claims associated with the Kabis
sampler is that no well purging is required in order
to acquire a sample that is representative of
formation water. Performance claims of the
various vendor participants in the study associated
with the merits of low volume purging or no
purging were beyond the scope of this study and
were not evaluated. Furthermore, the design and
operation of the Kabis sampler is such that a
reference sampler could not be co-located in the
monitoring wells for comparative purposes. Thus,
quantitative comparisons of Kabis and reference
samples from the groundwater monitoring wells
were not possible in this study.
14
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Section 4 — Performance Evaluation for Kabis Sampler
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. The Kabis Model I
and Model II samplers were used interchangeably
in these tests. They are identical in design and
method of operation and only differ by size of
sample collected. All data are combined and
reported under the term "Kabis sampler."
Sampler Precision
The precision for both Kabis and reference
samples from the first four standpipe trials is given
in Table 5. The first four trials consisted of low
(10-20 |ag/L) and high (175-225 |ag/L) target
compound concentrations, with sample collection
at shallow (17 feet) and deep (91 feet) locations in
the standpipe, as outlined previously in Table 3.
Relative standard deviations are tabulated by
compound with 4 test conditions (low
concentration at shallow sampling depth, high
concentration at shallow sampling depth, and so
on) shown for each compound, for a total of 24
cases. The final column in the table is the result of
the F-ratio test used to assess whether the
technology and reference precision values are
statistically different. The value/* tabulated in the
final column of the table is a measure of the
observed difference between the two values in
probabilistic terms. Values ofp that are close to 1
indicate small differences between the two
precision values, and low values of p indicate
greater differences. Values ofp that are less than
0.05 are indicative of statistically significant
differences that 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 being compared 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%. In other words, such an
observed difference would be highly unlikely. For
values of p less than 0.05, it is more likely that
some systematic bias exists between the two sets
of data.
The results shown in Table 5 can be summarized
as follows. Relative standard deviations from low
and high sample concentrations do not
significantly vary for both Kabis and reference
data. The greatest imprecision in the Kabis and
reference results are encountered for 112TCA in
the deep collection, low concentration test.
Preliminary evaluations of GC/MS performance
carried out prior to the field demonstration
revealed that this compound had higher analytical
uncertainty than the other target compounds, so
the observed effect can be attributed to the
analytical method and not the sampling process.
The median RSD for all compounds and all trials
was 10.7% for the Kabis sampler and 8.7% for the
reference samples. Sixteen of the Kabis sampler
precision values were less precise than the
reference values, and 8 were more precise than the
reference values. The results of the F-ratio test
indicate that only 1 of the 24 cases had a value of
p that was less than 0.05. Thus, differences in
precision between Kabis and reference samples are
statistically insignificant in 23 of the 24 cases.
Comparability to Reference
The comparability of the Kabis sampler data with
reference data for standpipe trials 1 through 4 is
given in Figure 4 and Table 6 and are expressed as
percent differences. Percent difference values
were computed for each of the six target
compounds in the four standpipe trials for a total
of 24 cases. The difference values for the Kabis
sampler range from -39 to 18%, with a median
value of-3%. By compound, the greatest
variability in results is seen for 12DCA, PCE and
TCE and the lowest for benzene and 112TCA.
Percent difference values for 14 of the 24 results
shown in Table 6 were less than zero with another
10 values above zero, thus no consistent bias in
either direction is observed when all cases are
grouped together. A t-test for two sample means
was performed to assess whether the differences
between the Kabis sampler and reference mean
values could be attributed to random variation or
to a systematic bias for each case. As noted
previously in the discussion on precision, values of
15
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p that are less than 0.05 are suggestive of a
systematic bias between the Kabis and reference
sample results. Most of the results (16 of 24) show
no statistically significant difference between
Kabis and reference results. T-test results for 8 of
the 24 cases have values ofp less than 0.05. Five
of those 8 cases show a Kabis sampler negative
bias ranging from -14 to -39% and these all occur
at the high VOC concentration levels. Negative
bias is judged to be of most importance since only
VOC losses are expected during the sampling
process. Negative biases in excess of 25% were
observed for 2 PCE cases at high VOC
concentrations at both shallow and deep sample
collection points. If one were to use a negative
sampler bias performance criteria of 25% or
greater as unacceptable performance, these results
show that the sampler would perform acceptably
for all compounds tested except PCE. Actual
performance criteria for a particular application
may vary and should be established by the site
investigator on a case-by-case basis.
TableS. Precision Summary for Kabis and Reference Sample
Compound
11DCE
12DCA
BNZ
TCE
112TCA
PCE
Cone.
Level
Low
Low
Hiah
High
Low
Low
High
High
Low
Low
High
Hiah
Low
Low
Hiah
High
Low
Low
High
High
Low
Low
High
Hiah
Sampling
Depth
(ft)
17
91
17
91
17
91
17
91
17
91
17
91
17
91
17
91
17
91
17
91
17
91
17
91
Kabis
Precision
(% RSD)
14.1
7.3
11.4
11.3
5.6
2.9
8.9
5.3
5.8
6.8
10.7
8.0
6.0
18.0
10.6
11.4
15.4
25.8
7.5
5.7
11.0
19.7
13.3
12.6
REF
Precision
(% RSD)
7.2
11.7
7.9
9.3
5.5
9.6
4.6
10.9
7.6
7.0
4.1
9.2
15.3
12.0
8.7
9.4
12.1
17.6
6.1
8.6
4.6
4.9
11.2
7.5
F-Ratio
3.58
2.32
2.14
1.08
1.34
8.79
5.15
4.34
1.62
1.04
7.36
1.68
7.47
2.30
1.11
1.16
1.35
2.04
1.73
1.06
4.78
15.52
1.28
7.5
F-Ratio
Test
P
0.24
0.44
0.48
0.94
0.78
0.06
0.14
0.18
0.65
0.97
0.08
0.63
0.08
0.44
0.92
0.89
0.78
0.51
0.61
0.39
0.16
0.02
0.81
0.96
Notes: Values of p less than 0.05 are shown in bold.
REF = reference measurement
16
-------
I]
a-20'u§,t@'7ft
a-20Cy§/L@ 17 It.
j2_^20Q_ijjj/L_^91Jl}
Figure 4. Kabis sampler comparability with reference
samples from the standpipe trials.
Table 6. Comparability of Kabis and Reference Sample Data from Standpipe Trials
Compound
11DCE
12DCA
BNZ
TCE
112TCA
PCE
Cone. Level3
Low
Low
High
High
Low
Low
High
High
Low
Low
High
High
Low
Low
High
High
Low
Low
High
High
Low
Low
High
High
Depth (ft)
17
91
17
91
17
91
17
91
17
91
17
91
17
91
17
91
17
91
17
91
17
91
17
91
Kabis Difference (%)
-4
6
1
-14
14
11
18
-2
3
5
5
-11
-6
1
-14
-24
-9
-2
7
-5
-9
-3
-26
-39
t-Test° p
0.60
0.37
0.84
0.04
<0.01
0.04
<0.01
0.75
0.58
0.30
0.41
0.07
0.42
0.92
0.04
<0.01
0.31
0.87
0.18
0.26
0.10
0.76
<0.01
<0.01
3 The low-level concentration was in the range of 10 to 20 (jg/L for all 6 target compounds. The high-level
concentration was in the range of 175 to 225 (ig/L.
b The t-test was used to compare the differences between the Kabis and the reference results for each compound in each
trial. The value p yields a quantitative estimate in probabilistic terms of the likelihood of the difference being
attributable to random variation alone. See text for further details.
17
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Blank and Clean-through-Dirty
Performance
The results from standpipe trials using blank
solutions show that the Kabis sampler reported
nondetectable levels for all six target compounds.
These results indicate that a Kabis sampler, when
decontaminated using the procedures specified in
Section 2, will not contaminate a sample with
chemical carryover from previous use.
The results of the clean-through-dirty test at the
standpipe are shown in Table 7. The sampler was
lowered through a layer of relatively high (-200
|jg/L) target VOC concentrations at the top of the
standpipe for sample collection at a depth of 35
and 91 feet in water with lower (approximately 15
to 50 |Jg/L) VOC concentrations. The tabulated
results are shown in terms of percent difference
relative to the reference samples collected
simultaneously with the Kabis samples. Note that
the tabulated difference levels for this trial are raw
values in the sense that they are not normalized
with the percent difference levels shown in Table
6. Difference levels for the Kabis sampler for all
compounds at both depths vary from 38 to 187%,
giving evidence that the sampler is either
entraining contaminants from the dirty layer or it
is collecting a partial sample as it is lowered
through the dirty layer. This carryover may be of
concern when the sampler is deployed at a
multiscreened well with high levels of
contaminants overlying lower contaminant levels
at the desired sampling depth.
Monitoring Well Results
Kabis sampler results from groundwater
monitoring samples collected at four wells are
shown in Table 8 alongside reference data from
the same wells. Four replicate samples were taken
with the Kabis sampler and the reference sampler
(a submersible electric gear pump), and relative
standard deviation values are also given in the
table. A few general observations from these data
are warranted: First, the field trials were carried
out primarily to provide an opportunity to observe
the deployment and operation of the technology
under actual field conditions. Second, formal
statistical analyses of these data have not been
carried out since the standpipe trial data set is
judged to be a superior data set for the
determination of precision and comparability to a
reference measurement. The data are shown for
qualitative comparison with the standpipe results,
and significant differences are noted where
appropriate.
Table 7. Clean-through-dirty Test Results for the Kabis Sampler
Com-
pound
11DCE
12DCA
BNZ
TCE
112TCA
PCE
Sampling
Depth
(ft)
35
91
35
91
35
91
35
91
35
91
35
91
Kabis
Average
Concentration
(ug/L)
71.2
23.4
102.3
32.7
85.6
28.2
67.7
25.5
102.2
43.3
83.1
31.0
Kabis
Precision
(%RSD)
4.2
9.8
14.9
18.2
5.3
12.4
11.5
18.0
20.2
19.9
6.3
13.6
Reference
Average
Concentration
(ug/L)
31.9
13.3
38.7
14.2
37.6
13.7
33.2
13.8
41.1
15.1
51.8
22.5
Reference
Precision
(%RSD)
18.2
11.6
18.1
16.7
29.0
6.7
2.9
12.6
7.7
10.6
9.6
7.0
Kabis
Percent
Difference
123
75
164
130
127
106
104
85
149
187
160
38
18
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Table 8. Kabis Sampler and Reference Pump Results from Groundwater Monitoring
Wells
Well No.
06-11 MW
06-04 MW
12-09MW
06-2 MW
Kabis
Average TCE
Concentration
(ng/U
386
338
11.2
ND (<5)
Kabis
Precision
(%RSD)
3.5
14.7
10.8
—
Reference
Average TCE
Concentration
(ng/U
480
596
11.2
ND (<5)
Reference
Precision
(%RSD)
5.1
6.4
10.8
—
Note: ND = not detected.
The data in Table 8 reveal that sampler precision
in the field was similar to that observed at the
standpipe. No assurances can be given that the
concentration of TCE in the well was stable over
the duration of the sampling event in each well;
thus formal comparisons between the two sets of
data are not done. Both the Kabis sampler and the
reference pump samples were nondetectable for
the well with no TCE. These blank results
indicate that the Kabis sampler, when
decontaminated using normal procedures, is not a
potential source of contamination in low-level
sampling operations.
Sampler Versatility
The performance parameters for the Kabis sampler
discussed previously reveal that it can collect
water samples contaminated with VOCs of
varying volatility at a range of sampling depths.
However, some evidence of a significant
systematic bias is observed when results are
compared with those of a reference method.
Evidence of negative sampler bias is judged to be
of greatest importance since it may result in
underreporting of actual groundwater
concentrations. Observed cases of negative
sampler bias in excess of -25% occur for high
concentrations of PCE and TCE. A statistically
significant negative sampler bias of a lesser
magnitude is also observed for 11DCE and TCE
cases. In light of these considerations, the Kabis
sampler is judged to have limited versatility.
Deployment Logistics
The following observations were made during
testing of the Kabis sampler at both the standpipe
and groundwater monitoring wells.
• Only one person is required to operate the
sampler. Training requirements are minimal,
with about 1 hour of training required for a
technician to become proficient in routine
field use of the equipment.
• The equipment is lightweight, compact, and
requires no external power to operate.
• A moderate level of manual dexterity is
required when removing the filled VOA vials
from the sampler. Care must be taken to keep
both the sampler and the vials upright when
removing and capping. Failure to do so may
result in spilled samples, resulting in unwanted
air bubbles in the capped vial. Dexterity is
also required in adding a dilute acid
preservative prior to capping the sample.
• The sampler is designed for portable use at
multiple wells and can be decontaminated in
the field with a detergent rinse followed by
several distilled water rinses.
• The sampler is maintenance free, with no
moving parts.
• The sampler is not suitable for well purging.
In instances where well purging is required, an
alternative means of purging is required.
• The sampler cannot be used where sampling
protocols require the use of pre-preserved
sampling vials or Teflon-lined septum caps in
vials.
Performance Summary
Kabis sampler performance is summarized in
Table 9. 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
Kabis sampler can be used to collect VOC-
contaminated water samples that are statistically
comparable to a reference method with regard to
19
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both precision and accuracy. Some indications of
significant sampler bias were observed in selected
trials. Low recoveries were observed for TCE and
PCE at high VOC concentrations at the deeper (91
feet) sampling depth evaluated in this study.
The clean-through-dirty trials also gave evidence
that the sampler may carry over contaminants
from an overlying dirty layer in a water column.
See Section 5 for vendor suggestions to remedy
this limitation.
Table 9. Performance Summary for Kabis Sampler
Parameter
Precision
Comparability with
reference samples
Sampler versatility
Logistical requirements
Completeness
Purchase cost
Size and weight
Other
Summary
For 6 target compounds at low (20 |ig/L) and high (200 |ig/L) concentrations
and at 17-foot and 91 -foot sampling depths:
Relative standard deviation range: 2.9 to 25.8% (reference: 4.1 to 17.6%)
Median relative standard deviation: 10.7% (reference: 8.7%)
In 23 of 24 standpipe test cases, Kabis precision was statistically comparable
to the reference sample precision.
For 6 target compounds at low (20 |ig/L) and high (200 |ig/L) concentrations
at 17-foot and 91 -foot sampling depths, Kabis and reference differences are
summarized as follows:
Percent difference range: -39 to 18%
Median percent difference: -3%
In 16 of 24 standpipe test cases, Kabis differences relative to reference
samples were statistically indistinguishable from 0%.
Statistically significant negative sampler biases in excess of 25% were
observed for PCE in 2 cases.
The Kabis sampler demonstrated consistent performance across the tested
range of compound volatility and sampler depth with regard to precision.
Some statistically significant sampler biases were observed for PCE and
TCE. In light of these biases, the sampler is judged to have limited versatility.
System can be operated by one person with a few hours of training.
System is lightweight and portable, with no power requirements.
Sampler was successfully used to collect all of the samples prescribed in the
test plan.
Model I $825
Model II $1,895
Model I: 1.75-inch external diam. x 17.4-inch length, 6.5 pounds
Model II 3.56-inch external diam. x 22.3-inch length, 15.5 pounds
Sampler cannot be used to purge a well. Other purging system must be
provided if purging is required.
Clean-through-dirty tests reveal that sampler may carryover contamination
from an overlying dirty water column into cleaner underlying water. In all test
cases, sample recovery in excess of 100% was observed. Sampler percent
differences, relative to reference samples, ranged from 38-187%.
Note: Target compounds were
and tetrachloroethene.
1,1 -dichloroethene, 1,2-dichloroethane, benzene, trichloroethene, 1,1,2- trichloroethane,
20
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Section 5 - Kabis Sampler Technology Update and Representative
Applications
Note: The following comments were provided by
the vendor and have not been verified as a part of
this ETV test. They have been edited only for
editorial consistency with the rest of the report.
Vendor Observations on Clean-
Through-Dirty Sampling
The Kabis Sampler, under certain conditions, may
intake a small amount of air/water interface water,
or whatever other liquid may be at the surface
during delivery. Fortunately, the sampler flushes
the sample container an average of about six vial
volumes before taking the actual sample. If the
surface layer is composed of extremely high
concentrations, occasionally minute quantities of
the surface contaminant remain in the sample,
possibly giving the indication of a false positive.
A field modification that can be performed under
these conditions involves the following: a 3A6 inch
ID by 2l/2-inch long piece of Tygon tubing which
has been heat pinched over a braided nylon cord at
one end is lightly pushed over the intake port of
the Kabis Sampler. Enough cord is included to
accommodate the sampler delivery depth from the
surface. The Tygon tubing effectively seals the
intake port from water intrusion until it reaches the
desired sampling depth, at which time the nylon
cord is pulled, removing the external plug from the
fill port, allowing the sampler's fill cycle to begin.
This modification was not employed during the
clean-through-dirty field trial of the Kabis Sampler
that was carried out to assess the degree of
contaminant carryover that occurs when lowering
the sampler through a high VOC concentration
layer into a low VOC concentration layer.
The Kabis Sampler may be used in nearly any
environment. The single exception is an acid
environment, due to the sampler's stainless steel
construction. Although the sampler was primarily
designed for delivery and use in groundwater
monitoring wells, it is equally used in water
supply wells, lakes, rivers, streams, ponds, bays,
and in the open ocean. In addition, the Kabis
Sampler has been used with success in storage
tanks containing high-energy radionuclides, food
processing vats, beer and other beverage process
vats, and on a variety of other liquids in various
industries. Wherever the need to sample liquids at
a specific depth is encountered, the Kabis Sampler
can be used or adapted for use.
Example Field Applications
Recent projects where the Kabis Sampler has been
deployed include chlorinated hydrocarbons at
Watervielet Arsenal in New York; DNAPL
contaminants at the Hanford facility in
Washington; light fraction hydrocarbons of
gasoline in Raccoon Creek, Pennsylvania; and
methyl-tertiary-butyl ether and perchlorates
associated with rocket fuel production at a former
Rocketdyne plant in California. The Kabis
Sampler samples directly into the sample container
under laminar flow and provides little disturbance
of the well as it is inserted; it is therefore suitable
for sampling dissolved minerals, heavy metals,
and salts of all kinds. The Kabis Sampler, because
of its sampling methodology, cannot be classified
as a bailer, though it is a grab-type sampling
device; it is a true discrete-point interval sampler.
Its applicability, though, unlike other discrete-
interval point samplers, covers a broad range of
environments and contaminants.
21
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22
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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/verifrpt.htmtf02).
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.
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. I, 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 (also available at http://www. epa.gov/etv/test plan.htm#monitoring).
23
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24
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Appendix A — Reference Pump Performance
Introduction
In addition to the sampling at the standpipe, the verification test design included the collection of vendor
samples from onsite groundwater monitoring wells. During monitoring well sampling, a reference pump was
colocated in the well with the vendor sampler. Both vendor and reference samples were collected
simultaneously to enable a comparison of the results. This appendix summarizes the reference sampler
chosen and outlines its performance and acceptability as a reference sampling technique.
System Description
The reference pump selected for use in this verification study was a submersible electric gear pump (Fultz,
Model SP-300, Lewistown, PA). Pump construction materials are stainless steel and Teflon, and pump
dimensions are 7.5 inches in length by 1.75 inches in diameter. This pump is a positive displacement device.
Water is introduced into the pump through a 60-mesh inlet screen into a stainless steel cavity. Two Teflon
gears inside the cavity push the water to the surface through 100 feet of Vi-inch outside diameter Teflon
tubing. An electronic controller is used to regulate the flow rate of the pump. Nominal sample collection
flow rates were in the range of 100-200 mL/min.
Performance Evaluation Method
The gear pump was tested during the standpipe trials in the same manner as the other vendor pumps. Water
samples were collected from the interior of the standpipe in four separate trials with both low (-20 |Jg/L) and
high (-200 |Jg/L) target concentrations at low (17 feet) and high (91 feet) sampling depths (see Section 3 for
additional details). Reference samples were collected from external sampling ports simultaneously with the
pump samples. In each trial, five replicate pump samples and five replicate port samples were collected.
Following collection, all samples were analyzed using the same onsite GC/MS system.
Pump Precision
A summary of pump precision is given in Table A-l. The percent relative standard deviation results for each
of the six target compounds in the four standpipe trials (low concentration—shallow, low concentration--
deep, and so on) for the gear pump and the external sampling port are given in columns 4 and 5, respectively.
The relative standard deviation range for the pump was 3.2 to 16.3%, with a median value of 7.6%. The port
precision data ranged from 2.8 to 16.2%, with a median value of 10.1%. The final column in the table gives
the value ofp associated with the F-ratio test (see Section 3 for a description of this test). Values ofp less
than 0.05 may indicate that significant, nonrandom differences exist between the two estimates of precision.
Out of 24 trials, only 2 show values ofp less than 0.05. These data indicate that pump precision was not
statistically different from the precision obtained from the reference samples taken directly from the standpipe
external ports.
25
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Table A-l. Precision of Gear Pump and Reference Samples in Stand pipe Trials
Compound
11DCE
12DCA
BNZ
TCE
112TCA
PCE
Cone.
Level
Low
Low
High
High
Low
Low
High
High
Low
Low
High
High
Low
Low
High
High
Low
Low
High
High
Low
Low
High
High
Depth
(ft)
17
91
17
91
17
91
17
91
17
91
17
91
17
91
17
91
17
91
17
91
17
91
17
91
Gear
Pump
Precision
(%RSD)
15.7
3.5
4.0
7.6
15.4
3.2
5.1
6.0
8.1
7.6
3.7
6.1
16.3
5.9
6.4
9.6
9.4
8.4
7.6
11.0
12.9
9.0
4.5
12.7
Port
Precision
(%RSD)
14.2
14.4
8.6
9.7
12.5
13.2
9.0
10.4
11.8
12.9
8.4
9.4
10.5
12.1
2.9
8.6
16.2
15.0
3.5
6.5
9.6
11.7
2.8
8.8
F-Ratio
1.11
14.7
4.81
1.28
2.35
14.1
3.18
2.38
1.71
2.30
5.02
1.83
2.41
3.12
4.82
1.55
3.38
2.81
4.76
3.43
1.36
1.50
2.28
2.38
F-Ratio
P
0.46
0.01
0.08
0.41
0.21
0.01
0.14
0.21
0.31
0.22
0.07
0.29
0.21
0.15
0.08
0.34
0.13
0.17
0.08
0.13
0.39
0.35
0.22
0.21
Pump Comparability with Reference Samples
Gear pump comparability is expressed as the percent difference relative to the reference sample concentration
by subtracting the average reference value from the average gear pump value, dividing the result by the
average reference value, and multiplying by 100. The percent differences for each of the 24 trials are given in
Table A-2. They range from -13 to 14% with a median value of 7%. A t-test for two sample means was used
to evaluate the statistical significance of the differences between the gear pump and reference samples. The
tabulated values of p give a quantitative measure of the significant of the observed difference in probabilistic
terms. Values ofp less than 0.05 suggest that a statistically significant bias may exist for the trial. With five
exceptions, all values ofp are greater than 0.05, indicating that overall, the differences between the two
sampling methods are statistically indistinguishable.
26
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Table A-2. Comparability of the Gear Pump with the Reference
Samples in Standpipe Trials
Compound
11DCE
12DCA
BNZ
TCE
112TCA
PCE
Cone
Level3
Low
Low
High
High
Low
Low
High
High
Low
Low
High
High
Low
Low
High
High
Low
Low
High
High
Low
Low
High
High
Depth
(ft)
17
91
17
91
17
91
17
91
17
91
17
91
17
91
17
91
17
91
17
91
17
91
17
91
Difference
(%)
-4
7
-3
13
24
10
-2
12
11
13
0
14
0
16
0
11
-6
7
1
10
-13
6
-6
6
t-Tesf
P
0.64
0.31
0.54
0.05
0.05
0.13
0.71
0.06
0.13
0.11
0.98
0.03
0.99
0.04
0.95
0.10
0.51
0.41
0.77
0.15
0.08
0.37
0.03
0.42
1 The low-level concentration was in the range of 10 to 20 (jg/L for all 6 target
compounds. The high-level concentration was in the range of 175 to 250 ng/L.
b The t-test was used to compare differences between Well Wizard and reference samples
for each compound in each trial. Small values of p (<0.05) are shown in bold and are
suggestive of a statistically significant difference. See text for further details.
27
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The percent recovery data for the gear pump are also shown graphically by target compound in Figure A-l for
each of the four standpipe trials. The horizontal dark line in the figure shows the 100% recovery level.
20 '
Percent Differenc
D en o e
1
—
E
w
W///////////J
W////////////////////A
—
|jn Jj| i
= - -
m
0-20 ng/L
©17f
B~200ng/L@91
0~20ng/L@17f
'-'~200 un/\ (n) 91
f
f
rrn
Ft 1=1
E
1 1
1
I
E
I
11DCE 12DCA BNZ TCE 112TCA PCE
Compound
Figure A-l. Percent recoveries of the reference pump by compound for the four
standpipe trials.
Reference Pump Performance Summary
The test data for the reference pump reveal considerable variability for PCE and 12DCA. However, the
variability and comparability for TCE, the only compound encountered in the field trials, are acceptable. The
mean relative standard deviation for TCE was 9.6% and the mean percent difference for TCE was 7%. The
data presented for TCE show that the pump is equivalent to the reference sampling method in terms of both
precision and accuracy and is acceptable for use as a reference standard.
28
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Appendix B — 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
B-l. 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 prefield
demonstration studies indicated that the field replicates were the same in composition so that they could be
treated as analysis duplicates.
Table B-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
1 0% of the samples
After beginning of day
CCC
Acceptance
Criteria
Ion abundance criteria
as described in EPA
Method TO-14
%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 Pilot Project Officer.
29
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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 B-l and B-2. Similarly, the results of the
PCE continuing calibration check for both instruments are shown in Figures B-3 and B-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 postanalysis batch calibration check samples are shown in Figure B-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
I
1
ej
fin -
Upper Control Limit
* •
^ 1412-hrStart
• |« 12-hr End
^ . ^
• " "
- * ' !
*
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 B-l. Calibration check control chart for TCE on GC/MS #1.
30
-------
GCMS (Taz) Control Chart
TCE Check Standard
140
130
120
S 110
90
80
70
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 B-2. Calibration check control chart for TCE on GC/MS #2.
GCMS (Pepe) Control Chart
PCE Check Standard
140
130
120
5?
» 110
100
80
70
60
Upper Control Limit
4Series1
• Series2
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 B-3. Calibration check control chart for PCE on GC/MS #1.
31
-------
GCMS (Taz) Control Chart
5?
>
g
u
&
"5 inn.
k Stan da
3 C
D C
0>
£
O
«n -
Upper Control Limit
*
•
• •
*
• *
»s
BE
B
tart
nd
•
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 B-4. Calibration check control chart for PCE on GC/MS #2.
GCflWS (Pepc and Taz) System Check
Relative Percent Difference -Daily Begin/End Check
50
4S
40
35
I
b
BPepc-TCE
D Pepe-PCE
BTar-TCE
STaz-PCE
a
15
•LI
S
I
Analysis Date
Figure B-5. GC/MS system check relative percent differences.
32
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