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ENVIRONMENTAL TECHNOLOGY VERIFICATION PROGRAM
VERIFICATION STATEMENT

TECHNOLOGY TYPE:	GROUND-WATER SAMPLING TECHNOLOGIES

APPLICATION:	NARROW-BORE WELL WATER SAMPLING

TECHNOLOGY NAME:	Model MB470 Mechanical Bladder Pump

COMPANY:	Geoprobe Systems Inc.

ADDRESS:	601 N. Broadway	PHONE: (800) 436-7762

Salina, KS 67401	FAX: (785) 825-2097

WEBSITE:	www.geoprobe.com

EMAIL:	info@geoprobe.com

PROGRAM DESCRIPTION

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 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.

Verification of contaminated site characterization and monitoring technologies is carried out within the
Advanced Monitoring Systems (AMS) Center, one of seven ETV verification centers. Sandia National
Laboratories, a Department of Energy laboratory, is one of the verification testing organizations within
this ETV Center. Sandia collaborated with personnel from the US Geological Survey and Tyndall Air
Force Base to conduct a verification study of ground-water sampling technologies for deployment in
narrow-bore, direct-push wells at contaminated sites with potential ground-water contamination. This
verification statement provides a summary of the results from a verification test of the Model MB470
Mechanical Bladder Pump manufactured by Geoprobe Systems Inc.

EPA-VS-SCM-56 The accompanying notice is an integral part of this verification statement.

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DEMONSTRATION DESCRIPTION

The performance of two ground-water sampling technologies was evaluated at the US Geological Survey
Hydrological Instrumentation Facility at the NASA Stennis Space Center in southwestern Mississippi
and at Tyndall Air Force Base near Panama City, Florida. Each technology was independently evaluated
to assess its performance in the collection inorganic cations, commonly encountered in ground-water, as
well as volatile organic compound- (VOC) contaminated ground-water.

The verification test, conducted over a one-week interval in February 2003, incorporated the use of a 5-
inch diameter, 100-foot standpipe at the USGS facility. The standpipe, serving as an "above-ground"
well, was filled with tap water spiked with various concentration levels of five target inorganic cations
(calcium, iron, magnesium, potassium and sodium) and six volatile organic compounds. Target VOC
compounds (vinyl chloride, methyl-tertiary butyl ether, cis-l,2-dichloroethene, benzene, trichloroethene
and ethyl benzene) were chosen to represent the range of VOC volatility likely to be encountered in
normal sampler use. Target cation concentrations were in the range of 5 to 100 mg/L and VOC
concentrations were in the range of 50 to 100 |ag/L. Water sampling ports along the exterior of the
standpipe were used to collect reference samples at the same time that ground-water sampling
technologies collected samples from the interior of the pipe. Trials were carried out at two different
inorganic cation concentrations, a single VOC concentration, and sampler depths ranging from 17 to 76
feet. An un-spiked, tap-water, blank sampling trial was also included in the test matrix. A total of 48
cation and 24 VOC samples were collected with the sample count equally split between vendor and
reference sampling methods.

The standpipe trials were supplemented with additional trials at six, 1-inch internal-diameter, direct-push-
installed wells at Tyndall Air Force Base. Sampling at narrow-bore, direct-push wells provided an
opportunity to observe the operation of the sampling system under typical field-use conditions. A simple
reference sampler was deployed alongside the vendor technology such that co-located, simultaneous
samples could be collected from each well. Principal contaminants at the Tyndall monitoring wells
included trichloroethene and its degradation products as well as hydrocarbon contaminants such as
benzene and ethyl benzene. Ground-water VOC concentrations ranged from low |Jg/L to low mg/L
levels. A total of 96 ground-water samples were collected, with the sample count equally split between
vendor and reference methods.

All technology and reference samples were analyzed by an offsite laboratory utilizing EPA SW-846
Standard Methods 301 OA (Acid Digestion of Aqueous Samples and Extracts For Total Metals by FLAA
or ICP Spectrometry) and 6010B (Inductively Coupled Plasma Atomic Emission Spectrometry) for
inorganic cation analysis and EPA SW-846 Standard Method 8260B (Volatile Organic Compounds by
Gas Chromatography/Mass Spectroscopy) for VOC analysis. The overall performance of the ground-
water sampling technologies was assessed by evaluating sampler precision and comparability with
reference samples. Other logistical aspects of field deployment and potential applications of the
technology were also considered in the evaluation.

Details of the demonstration, including an evaluation of the sampler's performance, may be found in the
report entitled Environmental Technology Verification Report: Geoprobe Systems Inc., Mechanical
Bladder Pump, ModelMB470, EPA/600/R-03/086.

TECHNOLOGY DESCRIPTION

The Model MB470 is a narrow-diameter (25.5-inch length x 0.47-inch outside diameter) bladder pump
suitable for deployment in direct-push-installed ground-water wells. The pump consists of an internal,
concentrically corrugated, flexible bladder that is positioned within a rigid stainless steel tube. The
bladder's internal volume can be reduced by applying a vertical force to collapse the bladder along it
longest dimension. The bladder is equipped with one-way inlet and outlet check valves and passively fills

EPA-VS-SCM-56 The accompanying notice is an integral part of this verification statement.

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with water when the pump is at depth in the well as a result of the hydrostatic pressure exerted by the
surrounding water column. Following the bladder fill cycle, a length of rigid tubing running from the pump
to the surface is pushed downward at the surface in order to collapse the bladder and push water to the
surface. The pumping sequence consists of repeated fill-compress cycles, using either a hand-operated
crank or an electric motor and actuator positioned on the top of the well head. The narrow-diameter
sampling pump with an inert bladder design offers the advantage of minimizing sample turbulence, which
can result in loss of VOCs in the sample, as well as eliminating contact of the water with an air vacuum and
further potential VOC losses.

Pump accessories include a hand-crank mechanical actuator, an electric-motor actuator (currently under
development) and various tubing configurations. The measured flow rate of the pump (equipped with the
motor-driven actuator) at a depth of 35 feet below the surface with a 30-foot water column above the pump
was approximately 100 mL/min. Higher flow rates were observed with the hand-crank actuator accessory.

Costs for the pump and accessories are as follows: pump, $430; mechanical actuator, $240; electrical
actuator (undetermined). Concentric tubing sets are priced as follows: HDPE (outer) /FEP (inner), $100
per 50-foot roll; HDPE/LDPE, $54 per 50-foot roll.

VERIFICATION OF PERFORMANCE

The following performance characteristics of the Model MB470 mechanical bladder pump were
observed:

Precision: The precision of the sampler was determined through the collection of a series of replicate
samples from a number of standpipe trials that included known concentrations of inorganic cations and
VOCs. Sampler depths ranged from 17 to 76 feet. Sampler precision, represented by the percent relative
standard deviation, for all target cation compounds at all concentrations and sampling depths evaluated
in this study ranged from 0.3 to 5.0 percent with a median value of 0.9 percent. Precision for VOCs at a
single concentration and multiple sampler depths ranged from 0.2 to 3.4 percent with a median value of
1.2 percent. Pump precision measured in the Tyndall field trials was similar to that observed in the
standpipe trials for the target cations. Tyndall monitoring-well field trials revealed considerably more
variability in the replicate samples from the pump and co-located reference sampler for VOCs.

Comparability with a Reference: Mechanical bladder pump results from the standpipe trials were
compared with results obtained from co-located external reference port samples that were collected
simultaneously. Both bladder pump and external port samples were analyzed at an off-site laboratory
using standard EPA methods for inorganic cations and VOCs. Sampler comparability is expressed as
percent difference relative to the external port data. Sampler differences for all target cations compounds
at all concentrations and sampler depths in this study ranged from -12.6 to 3.6 percent with a median
percent difference of 0.0. Sampler differences for all VOC compounds at all sampling depths ranged
from -5.0 to -0.3 percent with a median value of -2.5 percent.

Two statistical tests, the F-ratio test and the t-test for two sample means, were used to assess whether the
observed differences at the standpipe between the mechanical bladder pump and external port sample
precision and mean pump and external port target compound concentrations were statistically significant.
The tests show that the observed differences between the bladder pump and port samples with regard to
both precision and accuracy can be attributed to random variation. Thus, no statistically significant
difference exists between the results from the bladder pump and the external port samples.

The comparability of the pump with the reference sampling method for target cations at Tyndall
monitoring wells was similar to that observed during the standpipe trials. Comparability results for
VOCs were considerably more variable with percent differences ranging from -29.6 to 34.6 percent with
a median value of -8.3 percent for all compounds detected at Tyndall. The controlled aspects of the
standpipe tests should be considered in combination with the Tyndall field test results for a

EPA-VS-SCM-56 The accompanying notice is an integral part of this verification statement.

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comprehensive understanding of pump performance.

Versatility: Sampler versatility is the consistency with which it performed with various target
compounds, concentration levels, and sampling depths. The mechanical bladder pump performance did
not vary with changes in compounds or concentration levels. Deployment of the pump at depths in
excess of 50 feet may result in flow rates that are deemed unacceptable for some sampling applications.
In general, the Geoprobe mechanical bladder pump is regarded as a versatile technology and applicable
for sampling the types of inorganic and VOC contaminants from narrow-diameter direct push wells.

Logistical Requirements: The sampler can be deployed and operated in the field by one person. Several
hours of training are adequate to become proficient in the use of the system. The system requires a
source of DC or AC power when used with the electric-motor actuator (currently under development).
The bladder pump can be used as a dedicated sampler or as a movable sampler; however,
decontamination procedures are required when moving the pump from well to well.

Overall Evaluation: The results of this verification test show that the Geoprobe mechanical bladder
pump and associated mechanical actuator accessories can be used to collect inorganic cation- and VOC-
contaminated water samples from monitoring wells such that results are statistically comparable to
reference samples. The system is specifically designed for use in narrow-bore (0.5-inch minimum
internal diameter) wells. Furthermore, the pump is compatible with sampling programs that incorporate
low-volume purge methodologies.

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

Margie Tatro
Director

Energy and Critical Infrastructure Center
Sandia National Laboratories

EPA-VS-SCM-56 The accompanying notice is an integral part of this verification statement.

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