Research, Innovation And Technology Support: National Exposure Research Laboratory Characterization Research Division; Las Vegas


c/EPA
United States
Environmental Protection
Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478	December 1995
National Exposure Research Laboratory
Characterization Research
Division - Las Vegas
Research,
Innovation
and
Technology Support
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U.S. Environmental Protection Agency, Characterization Research Division - Las Vegas-
0192ODC94

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U.S. Environmental Protection Agency
National Exposure Research Laboratory
702/798-2100
Characterization Research Division - Las Vegas
Office of the Director
Wayne N. Marchant, Director
702/798-2525
John M. Moore, Assoc. Director
lor Research Operations
702/798-2522
FAX: 702/798-2233
ODC	Lorraine Payne (2525)
Monitoring Sciences
Branch
Richard J_ Garnas, Chief
702/798-2237
FAX: 702/798-2692
MSB	Joann Menke (2237)
Research Areas
•	Non-point Sources
•	Global Climate Research
•	Landscape Ecology
•	Landscape Characterization
•	Wildlife Indicators
•	Habitat/Biodiversity
•	Remote Sensing Research
•	Remote Sensing Support
•	Spatial Information Sciences
Program Operations
Staff
Charles H. Nauman,
Director
702/798-2564
FAX: 702/798-2380
POS Liz Sutton (2564)
Analytical
Sciences Branch
Christian G. Daughton,
Acting Chief
702/798-2207
FAX: 702/798-2261
ASB	Marilyn Janunas (2609)
Jan Contreras (2383)
Research Areas
•	immunoassay/Biosensors
•	Groundwater
•UST
•	Surface/Subsurface
Characterization
•	Human Exposure
•	Analytical Methods
•	QA Research
•	Field Methods
•	Technical Support Center
•	SITE Program
•	Consortium for Site
Characterization Technologies
•	Drinking Water Rad QA
Co L'sr:.|t!Ki Units
Office of Radiation
and Indoor Air
Jed Harrison
Director
ORIA 702/798-2476
Office of
Civil Righto
Pat A. McKenzie
Area Director
OCR	702/796-2512
Human Resouroea
Office • Las Vtgae
Arthur Sandoval, Jr.
Director
HRO	702/796-2414
Financial Management
Center
Alan B. Lewis
Financial Manager
FMC	702/798-2485
& Printed on Recycled Paper
8140dc96 (rev 11/9S)

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TABLE OF CONTENTS
INTRODUCTION TO THE TECHNOLOGY SUPPORT CENTER
1. Technology Support Center
CURRENT FIELD SUPPORT TECHNOLOGIES
1.	Soil-Gas Measurement
2.	Field Portable X-Ray Fluorescence
3.	Mobile Mass Spectrometer
4.	Geophysics: A Key Step in Site Characterization
COMPUTER SOFTWARE
1.	Assess: A Quality Assessment Program
2.	Hypertext: A Showcase for Environmental Documents
3.	Scout: A Data Analysis Program
4.	Geo-EAS: Software for Geostatistics
5.	Geophysics Advisor Expert System
6.	Cadre: A Data Validation Program
REMOTE SENSING TECHNOLOGIES
1.	ARC/INFO Concepts and Terminology
2.	Accessing Geographic Information Systems (GIS) Technology
3.	Geographic Information systems: An Overview
4.	GIS Planning Process
5.	Remote Sensing in Environmental Enforcement Actions
6.	Topographic Mapping for Environmental Assessment
7.	Remote Sensing Support for RCRA
8.	Wetlands Delineation for Environmental Assessment
9.	Photogrammetry for Environmental Measurement
10.	Global Positioning System (GPS) Technology
11.	Historical Maps and Archiving for Environmental Documentation
RADIATION MONITORING
1.	Field Screening Methods for Radioactive Contamination
2.	Internal Dosimetry for Radionuclides in Humans
3.	Ambient Gamma Radiation Monitoring

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SPECIALTY AREAS
1.	Immunochemistry for Environmental Monitoring
2.	High Resolution Mass Spectrometer
3.	Open Path FT-IR Use in Environmental Monitoring
4.	Continuous Monitoring with Purge-and-Trap Gas Chromatography
5.	UV-Vis Luminescence in Field Screening and Monitoring
6.	Robotics Technology in Environmental Sample Preparation
7.	Guidance for Characterizing Heterogeneous Hazardous Wastes
8.	Correct Sampling Using the Theories of Pierre Gy
9.	Special Analytical Services
10.	Performance Evaluation Samples
11.	Monitoring Airborne Microorganisms
12.	Biosensors for Environmental Monitoring
13.	EPA Training Programs Available Through The CRD-Las Vegas
14.	Mercury Preservation Techniques
CRD-LV INNOVATIVE TECHNOLOGY
1.	Field-Portable Scanning Spectrofluorometer
2.	Immunochemical Analysis of Environmental Samples
3.	Ion Mobility Spectrometry
4.	Capillary Electrophoresis for Environmental Monitoring
5.	Robust Statistical Intervals for Performance Evaluations
ISSUE PAPERS
1.	Survey of Laboratory Studies Relating to the Sorption/Desorption of Contaminants
on Selected Well Casing Materials
2.	Potential Sources of Error in Ground-Water Sampling at Hazardous Waste Sites
3.	Soil Sampling and Analysis for Volatile Organic Compounds
4.	Characterizing Soils for Hazardous Waste Site AssessoMts

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'EPA
INTRODUCTION
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
September 1992
(Revised 1995)
TECHNOLOGY SUPPORT
Technology
Support
Center
CRD-LV
Technology
Support Center
The U.S. EPA maintains
Technical Support Centers in
laboratories operated by the
Office of Research and
Development (ORD). These
Technical Support Centers
are dedicated to serving the
EPA Regions by supplying
high-quality, quick-response
technical services when the
scope of work is beyond the
technical capabilities of local
contractors.
The Characterization Re-
search Division in Las Vegas
(CRD-LV) has an active
Technical Support Center
(TSC) that responds to
requests from the Regions.
The TSC began in 1987 and,
originally, specialized in
Superfund support to Reme-
dial Project Managers
(RPMs) and On-Scene
Coordinators (OSCs). Since
1991, RCRA technical
support is available too.
The CRD-LV TSC specializes
in sampling and monitoring
technologies, quality assur-
ance, soil and ground water
sampling and special analyti-
cal services. This diversity of
expertise allows the TSC to
work with Regional personnel
throughout a site character-
ization event, from planning
and design to analysis and
data interpretation.
In addition to direct technical
support, the CRD-LV TSC
provides technical communi-
cation to the Regions through
the Technology Transfer
Project. Fact sheets, a
bimonthly newsletter entitled
The CRD-LV Bulletin", and
various presentations,
demonstrations, and poster
sessions help to keep
Regional personnel up to
date with the services
available through the TSC.
REGIONAL
requests
When RPMs/OSC or RCRA
Project Officers require
assistance through the CRD-
LV TSC, they contact the
Director by phone or by letter.
Before any work is commit-
ted, a written request must be
made. The TSC Director
determines the ability to meet
the demands of the request
and contacts the technical
staff appropriate to the
project.
After the work is done, a
report is issued to the re-
quester. Often these reports
go beyond the specific needs
of a particular site. Technical
information gained at
Superfund and RCRA sites
form the basis for a growing
background literature about
the specialized challenges of
complex environmental
matrices and also serve to
validate research-developed
procedures, methods, and
ideas.
TECHNICAL FOCUS
The TSC provides support to
the Regions in site character-
ization technologies such as
field-portable X-ray fluores-
cence (FPXRF), soil-gas
measurement, geophysics,
special analytical services,
quality assurance, chemical
analysis, radiochemical
analysis, geostatisffiSS,
statistical design, GIS, and
data interpretation.
When orHrite work is re-
quired, the TSC mobilizes
specialized teams equipped
with portable or deployable
instruments to assist the
Regions with the screening
and site-characterization
work that forms the basis for
all subsequent work.
1319ex92odc

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DOCUMENT
REVIEWS
In addition to the deployment
of field scientists, the TSC
helps the Regions evaluate
documents that have been
submitted by local contrac-
tors. This support is crucial
to wise decision-making by
the Regions. Team efforts
between the TSC and the
Region result in better
technology, quicker re-
sponse, and greater legal
defensibility.
PUBLICATIONS
The TSC Director is a
member of various technical
forums. This participation
often leads to the authorship
or coordination of issue
papers relating to the use of
innovative technologies for
monitoring and site charac-
terization.
Technical support projects
are documented in reports to
the Regions which vaty in
length and complexity
according to the project
needs. Projects can identify
areas for further research or
develop protocols for experi-
mental or sampling design.
The TSC participates in
interagency workshops with
the U.S. DOE and U.S. DOD
and together these organiza-
tions have published guid-
ance documents that address
the special challenges of
heterogeneous wastes at
federal and other facilities.
Through the Technology
Transfer Project, the TSC
"markets" its services to the
Regions and beyond. Fact
Sheets describe dozens of
analytical and field technolo-
gies that are available
through the TSC. Other
technology transfer activities
include the production of
videos outlining various CRD-
LV activities and the publica-
tion of a bimonthly newslet-
ter, The CRD-LV Bulletin,
that is distributed to a grow-
ing mailing list of more than
500 interested parties.
REFERENCES
Included here is a sampling of CRD-LV TSC publications. For a copy of any of these, or for a
packet of CRD-LV Fact Sheets, contact the manager of the TSC.
Characterizing Hfltflronenao^ Hfl^rHnns Wastes- Mothprte anri Racommenrlatinn^ gPA/
600/R-92/033, (The proceeding of a workshop held atjfofiEMSL-LV and co-sponsored by the
U.S. DOE.)
Lewis, T.E., A.B. Crockett, R.L. Siegrist, and K. Zarrabi, "Soil Sampling and Angfrsis for
Volatile Qrganir Compounds". EPA/540/4-91/001, (A Ground-Water Issue Paper.)
Breckenridge, R. P., J. R. Williams, and J. F. Keck. "Charaotorizlnn Soils For Hazarrimm Web-
Site Assessments". EPA/540/4-91/003 (A Ground-Watof toSHe Paper.)
FOR FURTHER INFORMATION
If you have questions about the services available through the Technology Support Center at
CRD-LV or wish to be added to the TSC mailing list, contact:
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Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Reatarch Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2270
(702) 798-3146 (Fax)
The Technology Support Center fact sheet series is developed and written by
Clare L. Qeriacb, Lockheed Environmental Systems & Technologies Company, Las Vegas.

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oEm
introduction
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
October 1990
(Revised 1995)
TECHNOLOGY SUPPORT
Soil-Gas
Measurement
The term "soil-gas" refers to
the atmosphere present in
soil pore spaces. Volatile
compounds introduced into
the subsurface can be
present in the gas phase or,
more commonly, can un-
dergo a transition from a
liquid or sorbed phase (pure
product, dissolved, or
adsorbed to soil) to become
part of the soil atmosphere.
Techniques for measuring
soil gases were developed
earty in this century for
agricultural studies and for
petroleum exploration.
Within the last several years,
soil-gas measurement has
become an accepted environ-
mental site-screening tool.
The technique is rapid, low
cost, and provides a high
yield of information when
carefully applied. Because it
is an indirect measure of
underlying contamination and
because of the potential for
false negative results, the
technique should be used
only for site screening and
not for confirmation.
The fate and transport of
contaminants and their
occurrence and detectability
in the soil gases are very
compound- and site-specific.
Soil-gas technology is most
effective in detecting com-
pounds having low molecular
weights, high vapor pres-
sures, and low aqueous
solubilities. These com-
pounds volatilize readily as a
result of their favorable gas/
liquid partition coefficients.
Once in the gas phase,
volatile compounds diffuse
vertically and horizontally
through the soil toward zones
of lower concentration.
Degradation processes (e.g.,
oxidation or reduction) can
eliminate or transform con-
taminants in the soil atmo-
sphere. The susceptibility of
a contaminant to degradation
is influenced by such factors
as soil moisture content, pH,
redox potential, and the
presence of microorganisms
that can degrade the com-
pound. Other site-specific
characteristics affecting
results are: soil type, air-filled
porosity, depth to the source,
barriers to vapor transport,
and hydrogeology. Because
site-specific factors influence
contaminant concentrations
detected in the soil gases, a
quantitative correlation
between soil-gas concentra-
tions and underlying contami-
nation is difficult to general-
ize.
applications
Soil-gas surveys can be used
to:
•	identify contaminants and
relative concentrations
•	identify sources; indicate
extent of contamination
•	monitor the progress of
cleanups
•	guide placement of subse-
quent confirmatory samples
(soil borings, monitoring
wells)
•	monitor at fixed vapor wells
(long-term monitoring)
•	detect leaks through use of
tracer compounds
Typical primary sources
include surface spills, leaking
tanks, pipes, trenches, dry
wells, or landfills. Contami-
nants from such sources
frequently reach the water
table, causing the ground-
water to become a source of
contamination to down-
gradient sites. The nature of
the source will influence the
vertical and horizontal disper-
sion of gas-phase contami-
nant vapors.
Contaminants detectable in
soil gases include many
common chlorinated solvents
and the lighter fractions of
petroleum products, sub-
stances that are widespread
environmental contaminants.
Of the 25 most commonly
encountered contaminants at
Superfund sites, 15 are
amenable to detection by soil-
gas sampling. Inorganic
contaminants that can be
detected by soil-gas sampling
include radon, mercury, and
hydrogen sulfide.
SELECTED COMPOUNDS DETECTABLE IN SOIL GASES
Aromatic hydrocarbons:
Chlorinated hydrocarbon*:
Benzene*, toluene, xylenes, naphthalene Chtoromethanee (e.g., chkxoform,
carton tetrachloride); chloroethanes;
Aliphatic hydrocarbons:
C, • Cl0 (e.g., methane, butane, pentane,
iso-odane cydohexane)
Mixturea:
Gaeoline, JP-4, various jet fuels
chloroethenes (e.g., vinyl chloride, dK tri-,
and perchloroethene)
Other:
COj, CS2, HjS, NOx, radon, mercury
compounds
1607EX90

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THE TECHNIQUE
DATA QUALITY
OBJECTIVES AND
QA/QC
SUMMARY
REFERENCE
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Soil-gas samples can be
collected by active or passive
methods. For active sam-
pling, a probe is driven into
the ground and soil gases are
pumped from the subsurface
into a sample container (e.g.,
evacuated canister, tube,
glass bulb, gas sample bag,
syringe) or through a sorbent
medium. For passive
sampling, a sampler contain-
ing a sorbent with an affinity
for the target analytes is
placed in the ground for a
period of time, and contami-
nants are collected by virtue
of diffusion and adsorption
processes. After exposure,
the passive sampler is
transported to a laboratory for
analysis. The most com-
monly used technique for
analyzing soil-gas samples is
gas chromatography (GC) in
combination with a detector
appropriate to the target
analytes. Analyses can be
done on- or off-site. Soil-gas
samples can also be
screened in the field using
organic vapor detectors,
which provide results ex-
pressed as total hydrocarbon
concentration relative to a
calibration standard.
The design of a soil-gas
survey depends on the data
required (e.g., identifying and
quantifying specific com-
pounds vs. measuring total
hydrocarbon concentration)
and the nature of the contami-
nation. A feasibility study is
recommended whenever
possible, particularly for sites
where little information is
available. Such a study can
be valuable in verifying the
effectiveness of the method at
the site, selecting the appro-
priate sampling and analytical
methods, choosing the best
sampling depth, and optimiz-
ing other operational details.
Because soil-gas surveying is
an intrusive technique,
precautions must be taken to
avoid buried utility lines,
tanks, or other objects.
Because soil-gas results
provide an indirect measure
of primary contamination,
data quality objective (DQOs)
for soil-gas surveys and the
Quality Assurance (QA)
required need not be as strict
as those for confirmatory
sampling and analysis of soil
or ground water. However,
because most soil-gas survey
objectives require compari-
son of data among points to
determine patterns of relative
concentration, the investiga-
tor must be able to determine
whether differences in value
are real or merely due to poor
method precision. Consis-
tency in procedures is
essential (i.e. collection and
analysis of replicate and
blank samples) and regular
checks of instrument calibra-
tion. Materials that come into
contact with samples should
be inert and easy to decon-
taminate.
Soil-gas measurement can
be an effective method for
determining the source and
extent of volatile contami-
nants in the subsurface.
Because of the many site-
and compound-specific
factors that can influence
results, soil-gas measure-
ment should be done only by
experienced field investiga-
tors. With proper QA and
judicious data interpretation,
this technique is a useful,
low-oost site screening tool.
SUMMARY OF ADVANTAGES AND LIMITATIONS
OF SOIL-GAS MEASUREMENT
Advantages
Rapid
Low cost
Real-time results
Minimal disturbance to site
Limitations
Indirect measurement
Interferences (false negatives are a problem)
Application limited to high volatility/low solubility
compounds
Mayer, C.L., Soil-Gas Surveys: Planning, Implementation, and Interpretation. EPA/600/X92/065
U.S. EPA. EMSL-LV. Las Vegas, NV. 1992.
FOR FURTHER INFORMATION
For further details on soil-gas measure-
ment, contact:
Lawrence A. Eccles
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2385
For general Technology Support assistance,
contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Us Vegas, NV 89193-3478
(702) 798-2270
(702) 798-3146 (Fax)
The Technology Support Center tact sheet series to developed and written by
Clare L. Gertach, Lockheed Environmental Systems & Technologies Company, Las Vegas.

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United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
November 1990
(Revised 1995)
TECHNOLOGY SUPPORT
&EPA
Field-Portable
X-Ray
Fluorescence

INTRODUCTION
THE SURVEY
Field-portable X-ray fluores-
cence (FPXRF) is a site-
screening procedure using a
small, portable instrument
(15-25 lbs, or 7-12 Kg) that
addresses the need for a
rapid turnaround, low-cost
method for the in situ analy-
sis of inorganic contaminants.
Traditional Contract Labora-
tory Program (CLP) methods
of analysis may take 20 - 45
days per site to complete and
the analysis would cost much
more than FPXRF. FPXRF
can measure inorganic
elements when used with the
proper radioisotope source
and the appropriate stan-
dards. FPXRF is capable of
simultaneous analysis of up
to six analytes per model.
More than one model can be
applied to each spectrum
obtained. This method is
useful at various levels of
analysis, with data quality
dependent upon the exten-
siveness of the survey, the
type of standards used, and
the reinforcement of data by
other collaboratory methods.
FPXRF can be used for
periodic monitoring as
remediation proceeds. The
following table includes the
elements that are on the
EPA's Inorganic Target
Analyte List, with asterisks
designating the ones quantifi
able by FPXRF.
The CRD-LV has been
requested to analyze six of
these elements to date:
arsenic, chromium, copper,
iron, lead, and zinc. Though
detection limits are highly
matrix dependent and site
specific, the detection limits
for these elements have been
in the 100 - 500 mg/Kg
range. The instrument used
at the CRD-LV is an X-MET
880.
TABLE 1
INORGANIC TARGET ANALYTE LIST
Aluminum
* Calcium
Magnesium
* Silver
"Antimony
* Chromium
Manganese
Sodium
"Arsenic
* Cobalt
* Mercury
* Thallium
* Barium
•Copper
* Nickel
* Vanadium
Beryllium
•Iron
* Potassium
*Zinc
* Cadmium
•Lead
* Selenium
Cyanide
* Indicates FPXRF quantifiable analytes.
An FPXRF survey is a com-
bined effort of field scientists
and geostatisticians. Ideally,
there is a pre-survey aerial
photographic evaluation of
the site, a screening on-site
to collect site-specific calibra-
tion standards, an off-site
calibration of the instrument,
and a final on-site visit for
data collection and quality
control. Then geostatistical
interpretation is done and a
site screening report is pub-
lished.
Typically a field survey is re-
quested by an EPA Region.
Remedial Project Managers
(RPMs) can contact local
contractors with the equip-
ment and expertise d do an
FPXRF survey. When spe-
cial help is needed, the RPM
may contact the CRD-LV for
expert advice. The team that
responds is equipped with an
FPXRF instrument and all of
the necessary supporting
equipment to adequately as-
sess the site. Using Jhe cali-
bration curve that has been
generated from site-specific
standards, the X-ray re-
sponses of the routine
samples are regressed
against this curve and an ana-
lytical result is generated.
Geostatistics, an interpretive
method which allows for the
similarity between neighboring
samples, is used to optimize
the sampling design prior to
the survey. After the sampling,
geostatistics is used to ana-
lyze the data and to produce
concentration isopleth maps.
0022EX90

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INSTRUMENTATION
HOW A FIELD
SURVEY IS
CONDUCTED
COST
ADVANTAGES AND
LIMITATIONS
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X-ray fluorescence is based
on the fact that atoms
fluoresce in a unique and
characteristic way. By
bombarding a sample with
energy, the instrument
causes an electronic instabil-
ity. As the instability relaxes
to a more stable energy level,
X-ray fluorescence is emitted.
The detector senses and
counts this spectrum of
radiation which is a finger-
print of the specific analyte
and, on this basis, identifies
the atom. Quantitation is
done against a calibration
curve that was generated by
the analysis of site-specific
standards.
X-ray fluorescence has been
a standard laboratory method
for years and the recent
availability of portable
instruments now allows this
method to be taken into the
field for use at hazardous
waste sites.
To effectively use FPXRF,
the field scientist must ask a
few questions. What is the
objective of the survey? What
data are needed? What is
the most efficient sampling
scheme? What are the data
quality objectives?
A complete FPXRF analysis
is based on calibration of
standards that are specific to
the site. These standards
are collected on the initial
site-screening visit and are
analyzed by a complete CLP
procedure in order to cali-
brate the FPXRF instrument.
Numerous in situ measure-
ments are made on the
hazardous waste site. QA/
QC is integrated into the
program. The resulting data
are not only quantitative, but
of known quality.
The average cost of in situ
FPXRF surveys, based on a
wide range of surveys
performed by the CRD-LV
team has been less than
$50,000. This cost includes
labor, transportation, an
aerial photographic pre-
survey, analysis of about 15
site-specific standards per
analyte, the FPXRF survey
of up to 150 measurements
per day, and a final report. A
typical survey takes about 3
days. The complete proce-
dure from pre-survey through
final report takes about 4-6
weeks.
Advantages
Low cost
Ease of operation - portable,
moves to any site
Rapid results - real time
(once site-specific standards are available)
Limitations
Complex data interpretation -
for geostatisticai investigations
Matffifvariability
type of soil influences results
Less sensitive than a complete*CLP analysis
REFERENCE
Raab, G. A., R. E. Enwall, W. H. Cole, III, M. L. Fab*v«ntf L. A. Eccles, July 1990, X-Ray
Fluorescence Field Method for Screening of Inorganic Contaminants at Hazardous Waste
Sites. In: Hazardous Waste Measurements, M. Simmons, Ed., Lewis Publishers, Chelsea, Ml.
FOR FURTHER INFORMATION
For FPXRF, contact. For Technology Support Information, contact:
Mr. William H. Engelmann
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 89478
Las Vegas, NV 89188-3478
(702) 798-2664
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2270
(702) 798-3146 (Fax)
The Technology Support Center fact sheet series Is devetooed and hu
Owe L Q§rt§ch, Lockheed Environmental Systems & Technologies Company,
Las Vegas.

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oEPA
INTRODUCTION
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
August 1990
(Revised 1995)
TECHNOLOGY SUPPORT
Mobile Mass
Spectrometry
Gas chromatography/mass
spectrometry (GC/MS) is the
EPA recommended method
for the analysis of volatile and
semivolatile organic com-
pounds. This proven analyti-
cal technique identifies and
quantifies organic com-
pounds on the basis of
molecular weight, character-
istic fragmentation patterns,
and retention time. Until
recently, it was not feasible to
bring a GC/MS instrument to
a hazardous waste site
because of its size and
weight, the need for strict
control of temperature and
humidity, and the effect of
vibration during transport.
With the growing demand for
field-portable instrumentation
in the environmental area,
rugged, smaller units have
been developed. Bruker
Instruments, Inc. supplied
CRD-LV with a complete
mobile mass spectrometry
system to test under the
Superfund Innovative Tech-
nology Evaluation (SITE)
program. The performance
of this system was demon-
strated at two Superfund
sites in Region I. The mobile
mass spectrometer was used
for the analysis of PCBs in
soil at the Re-Solve, Inc. Site
and for PAHs in soil and
VOCs in groundwater at the
Westborough Township Site.
Because GC/MS is the
preferred method for the
analysis of volatile and
semivolatile organic com-
pounds, mobile GC/MS is
anticipated to become the
major technology for field
analysis of these contami-
nants in the 1990s.
INSTRUMENTATION
The Bruker system (specifi-
cally the MEM) was consid-
ered the most advanced
instrument available for this
testing and was, therefore,
the only one evaluated.
When other instruments
become available, compari-
sons will be performed. The
Bruker MEM is ca. 22" x 28"
x 30" and weighs about 500
pounds. It can be mounted in
a four-wheel drive vehicle
and taken directly to the site.
This instrument is equipped
with built-in power, resistance
to shocks, and will operate
from -30°C to 50°C with no
external cooling or heating
requirements. The mass
spectrometer has a mass
range of 1-400 Daltons which
minimizes power consump-
tion. it can operate for 6-8
hours on battery power, or
indefinitely using a generator
or conventional AC power.
An MS-DOS 386 based data
system can be used to
acquire, analyze, and archive
all GC/MS data. Sampling
accessories are available for
a wide range of monitoring
situations: a "sniffer" with a
3.5 m GC column is used for
continuous air monitoring or
the thermal desorption of
organics from a soil surface.
A temperature programmable
GC with a capillary column is
also available.
The Bruker MEM offers
several analysis modeeand
sample introduction methods
which Can be chosen based
on the data quality objectives
(DQO) of the site. Two
modes, "rapid screening" and
"characterization", were
tested in the SITE demon-
stration. The rapid screening
mode allows a quick analysis
for up to ten organic com-
pounds simultaneously. The
more accurate characteriza-
tion mode follows a CLP-type
protocol, including an extrac-
tion, 5-point calibration, and
data acceptance windows.
Once the sample is intro-
duced, it passes through a
semipermeable membrane
into the ionization source
where it is fragmented into
characteristic ions. These
ions are then accelerated,
focused, and detected. The
resulting mass spectrum is
compared against known
compounds in the computer's
library. The quantitation limits
of the MEM vary depending
on several factors including:
•	analysis mode used
•	analytes detected
•	matrix analyzed
iSTtadO

-------
SCOPE
The desirability of field-
portable GG/MS instrumenta-
tion is obvious. The MEM
provides the Agency with an
instrument for field analysis
that is capable of achieving a
wide range of DQOs. Be-
cause of the proven track
record of GC/MS, field GC/
MS is a superior choice to
other novel techniques which
have been proposed for field
analysis but lack a basis in
routine or special environ-
mental applications. By
replicating the method of
choice for organic analysis in
a unit that can be deployed to
hazardous waste sites, the
favored technology is moving
on-site. The on-site results
can be compared easily with
CLP results. Decisions can
be made at the site, based on
early results, to focus subse-
quent and intensive sampling
in areas of greatest contami-
nation. More than a field
screening tool, portable GC/
MS provides field scientists
with an instrument of ac-
cepted integrity and demon-
strated value. It allows field
scientists and on-scene
decision makers an opportu-
nity to compare field results
with historical databases.
The development and
implementation of these
instruments is of great
interest to environmental
scientists, especially those
working within the historical
framework of the CLP.
ADVANTAGES AND
LIMITATIONS
FUTURE PLANS
^c>a'0N'%
^Oioqy
These newly tested field
methods are capable of
improving the overall reliabil-
ity of organic analysis in field
situations. As the technology
emerges, further break-
throughs in sensitivity, size,
and ruggedness will certainly
continue.
This Is a system specifically
designed for field use not a
laboratory instrument taken
to the field.
Advantages
Simplified operations
Rapid turnaround
Unambiguous identification
Equivalent to EPA method
Limitations
Complex, requires trained personnel
Field quality control
High initial equipment cost
Further testing of the Bruker
instrument and other
manufacturer's equipment is
planned. Evaluations of
these instruments and
comparisons between
laboratory and field analysis
data will address concerns
about volatile loss during
shipment from field to labora-
tory. More analytes on the
hazardous substances list
(HSL) will be quantified by
portable GC/MS. The use of
the system with its ancillary
"sniffer" for air testing will be
considered. Additional
automated sampling devices
will be developed and tested.
Computer software will be
modified to generate reports
in Agency format. Increased
demand for this instrumenta-
tion will guide research to
meet the growing needs of
environmental field scientists
REFERENCES
R°bb»J,- A-'nd ?•	."fjg'SS'i FWJ Purae and Trap Gas Chromatography
FOR FURTHER INFORMATION
For specific Information on mobile mass
spectrometry, contact:
Dr. Stephen Billets, Jr.
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2232
For further information on technology
support, contact:
Mr. K£RT3f6wn, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2270
(7#) 798-3146 (Fax)
Technology Support Center fact sheet series is developed and written by
Clare L Qmbch, Lockheed Environmental System &Technologies Company. Las Vega&
The

-------
United States	Office of Research arid	November 1991
Environmental	Development	(Revised 1995)
Protection Agency	Washington, DC 20460
TECHNOLOGY SUPPORT
f/EPA
INTRODUCTION
METHODOLOGY
SCOPE
Geophysics: A Key Step
in Site Characterization
Distance (fMt)
A frequent problem facing en-
vironmental scientists working
on the remediation of hazard-
ous waste sites is locating
subsurface contamination and
delineating features that influ-
ence its movement. When a
site manager requires infor-
mation about subsurface char-
acteristics with as littfe subsur-
face disturbance as possible,
geophysics offers an array of
techniques. Focusing on the
location and assessing the
extent of contamination can
lead to a more clearly defined
view of the site that will save
time, money and provide a
better degree of safety.
Geophysicists at The Charac-
terization Research Division
in Las Vegas (CRD-LV) are
experienced in using several
geophysical methods that
can aid in the detection and
definition of contamination.
This information can assist
the site manager with cost-
effective, reasonable options
during site characterization.
All geophysical techniques are
based on elements of physics
and geology. These methods
respond to the physical
properties of the subsurface to
infer the geological formations
and structure, and the pres-
ence, location, distribution and
size of buried objects.
Generally, the methods fall
into six categories:
•	seismic (including reflection
and refraction)
•	electrical methods (including
direct current resistivity and
electromagnetic
techniques)
•	magnetic
•	gravity
•	radiometric
•	ground-penetrating radar
Many of these measurements
can be made on the surface
of the ground, by airborne
methods, or in boreholes. By
observing some characteris-
tic of the measured signal,
the geophysicist is abie to
estimate the size, shape,
depth, and other characteris-
tics of the subsurface objects.
Sophisticated computer
algorithms are available that
aid the geophysicist in making
these interpretations. These
usually require some degree
of experience and expertise
on the part of the geophysi-
cist. Because of ambiguity in
the interpretations, usually
more than one geophysical
method is applied at a site.
The equipment used in
making geophysical measure-
ments varies but field-
deployable units are available
in all categories.
Successful use of information
from geophysical measure-
ments for site characteriza-
tion depends on the
investigator's ability to
understand and interpret
data. Factors include:
1)	the geologic and
hydrogeologic characteris-
tics of the contaminated
site.
2)	physical property differ-
ences related to natural
geologic occurrences,
such as those at contacts
between different kinds of
rocks.
3)	physical property changes
produced by contami-
nants, such as changes in
the electrical properties.
4)	conatreinto mat act within,
and on, a system, e.g., the
influence of large solution
cavities on ground-water
movement.
5)	sources and characteris-
tics of noise that can
obscure the signal and
interfere with data inter-
pretation.
The thoughtful use of geo-
physics in environmental
science benefits me site
manager in several ways. It
provides a reliable 'baseline'
characterization of a newly
identified site. It helps
decision makers to target
future characterization and
remediation efforts in a
focused manner. It aids in
0331EX91

-------
SCOPE (Continued)
ADVANTAGES AND
LIMITATIONS
*g	"Technology	^
O ,	Z
O	^L,PP°rt	Q
^	Project	£•
the ongoing monitoring of
remediation efforts.
When a site manager first
contacts a geophysicist,
several questions will arise.
Why suspect subsurface
contamination? How deep is
the buried object or plume? Is
historical data available about
the site? The Geophysics
Advisor Expert System was
developed to assist the non-
geophysicist managers in
evaluating what geophysical
techniques may be useful for
solving their site-specific
problems. It is designed to
assist their interactions with
the geophysicists. The
geophysicist may also ask for
a sample of soil or other
material from the area of
interest so that physical
property variations can be
evaluated. - Once background
work has been completed
(searching for historical data,
obtaining topographic maps
and aerial photographic
images, inspecting any other
geophysical data that is
available), the geophysicist
will select the best experi-
mental design to characterize
problems at the site. In some
cases, a preliminary site visit
is made. On the basis of the
background information and
the preliminary site visit, the
best geophysical methods
are chosen and work begins.
Geophysical measurements
follow good experimental and
sampling design strategies to
ensure that the best technical
accomplishment is achieved.
Following the data gathering,
the geophysicist uses com-
puterized modeling algo-
rithms to interpret the data
that were generated at the
site. Thoughtful data interpre-
tation is fundamental to the
success of any geophysical
effort.
The use of geophysical
measurements to determine
the location and extent of
subsurface contamination is
an Agency-accepted method
for site characterization.
Geophysicists are highly
trained and experienced
scientists. As more geo-
physicists enter the environ-
mental workplace, it is
expected that the demand
for, and the use of, this
expertise will increase.
Advantages
Surface geophysical
techniques provide a good
non-intrusive method for
characterization of subsur-
face features
Better safety consider-
ations due to the non-
intrusive aspect
Cost effective, some
methods can be used to
initially screen a large area.
Limitations
•	Results require interpreta-
tion and can be non-unique
•	Some methods require
highly trained personnel
•	Direct confirmation of
results still required
REFERENCES	~	:	
Introductory:
Benson, R.C., R. A.Qlaccum, and M. R. Noel, GeoDhvaicalTo^ni«..«»e > „ , ....
Waste Migration, U.S. EPA Environmental Monitoring
Olhoeft, a.. <3«&^A^ExpMSy«Bm. EPA Pro|M Report EPAAKXVW9/023, June 1989.
More Advanced:
Telford, W. M., L P. Geldart, R. E. Sheriff, and D A Keva 4nn//aw^««,i. , _
Press, 1976.	y'Applhd Geophysics, Cambridge University
FOR FURTHER INFORMATION
For more information about the geophysics
program at the CRD-LV, contact:
Dr. Aldo Mazzella
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2254
For information about the Technology Support
Center at CRD-LV, contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
\m) 798-2270
(702) 798-3146 (Fax)
(702) 798-3146 (Fax)
The Technology Support Center fast sheet series 1$ developed and written by
Clare L GMtoeh, Lockheed Environmental System & Technologies Company,
Las Vegas.

-------
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
July 1993
(Revised 1995)
TECHNOLOGY SUPPORT
&EPA ASSESS:
A Quality
Assessment
Program
INTRODUCTION
ASSESS is an interactive
program designed to assist
the user in statistically
determining the quality of
data from soil samples taken
at a hazardous waste site.
CRD-LV scientists have
developed this public-
domain, user-friendly Fortran
program to assess precision
and bias in the sampling of
soils. The total error in a
sampling regimen is the sum
of measurement variability
and natural variability of the
contamination. It is the field
scientist's challenge to
mitigate the measurement
variability by careful sample-
taking, thoughtful sampling
design, and the use of
recommended quality as-
sessment samples. The
greatest potential for error,
both random and bias, is in
the sampling step. Field
conditions, tool contamina-
tion, operator differences, all
can affect variability and bias
in a sample before it gets to
the analytical step.
The value of ASSESS is its
ability to detect and isolate
error at critical steps in the
sampling and measurement
function. Installation is
simple and is described in the
User's Guide referenced at
the end of this text.
FEATURES
ASSESS plots graphics
directly on the screen to give
the user a quick look at data
or results. All graphics can
be formatted to give hard
copy via pen plotters or other
graphics printers.
ASSESS checks for missing
data and for data input errors
of sufficient magnitude to fall
outside numeric parameters
that have been previously
set
Reports and plots can be
incorporated into
WordPerfect.
SCREENS AND
MENUS
After an introduction screen,
ASSESS presents screens
and menus beginning with
the Data Quality Objectives
(DQO) Screen. The user
inputs known information
about the site and sampling
method and desired confi-
dence ranges.
Next, the user may choose
the Sampling Considerations
Screen. This screen allows
entry of further specifics
about the field sampling,
such as, number of samples
taken, number of batches
analyzed, cost, and batch
data.
The next screen is the
Historical Assessment
Screen that provides options
for entry of historical data that
may be critical to the interpre-
tation of this sampling.
A Quality Assessment Data
Screen follows that allows the
user to view and edit the
quality assessment data that
are called for in the parent
document, A Rationale for
the Assessment of Errors in
the Sampling of Soils,
referenced at the end of this
fact sheet These quality
assessment samples are
fundamental to the
successful um of ASSESS.
They include samples that
will check for and evaluate
error in every sampling step.
At this point, it is possible to
produce scatter plots to
visually inspect the
contribution to the total error
that is made by any particular
quality assessment sample
with the confidence in the
error estimates being a
function of the number of
data.
The Transforms Screen
follows and it gives the user a
method for applying unary or
binary operations to the
entire data set. For example,
the field scientist or data
interpreter may wish to
truncate the data, view the
plot as a log or In function, or
perform a basic mathematical
operation on all data.
The Results Screen displays
variances for sample collec-
tion, batch dissimilarity, sub-
sampling error, and handling
differences. This screen also
shows the total measurement
20S8EX93

-------
SCREENS AND
MENUS (Continued)
DATA FILES
STATUS
HARDWARE
REQUIREMENTS
^ -r-	%
^ I echnology ^
o Support
project
GOLOSH
error. A report of the results
and a list of historical infor-
mation and the quality
assessment data may be
saved to a file or printed.
ASSESS is based on the use
of field duplicates, splits, and
performance evaluation
samples that isolate and
assess variability throughout
the measurement process.
An option is provided for the
use of duplicates and splits in
the calculation of variability
when inadequate types and
numbers of performance
evaluation samples exist.
ASSESS incorporates simple
ASCII text files that can be
created with any text editor.
Two output files can be
produced by ASSESS, one of
which can be read as a data
file by ASSESS and the
other, which is not ASSESS
readable, gives a report-like
document. A third type is
provided so that the user may
edit an input file without
entering all the data through
ASSESS.
ASSESS is currently avail-
able in Version 1.0. This is a
prototype environmental
software package. Further
development is planned and
input from field scientists and
EPA Regional personnel is
solicited so that the next
version may be more tailored
to user needs.
ASSESS is based on the
EPA publication, A Rationale
for the Assessment of Errors
in the Sampling of Soils, and
it is strongly recommended
that users familiarize them-
selves with the concepts in
that document before trying
to apply ASSESS.
Hardware requirements for using ASSESS are:
•	IBM PC (or compatible)
•	1.2 MB floppy disk drive 51/4" (or 31/2" DD or HD)
" ^^il'^s^G^andEG^6 '8 Hercules 9raphica card' monochrome display with graphics
•	Minimum 512 K RAM
•	Math coprocessor chip is recommended but not required
ffi
REFERENCES
ASSESS User's Guide, U.S. EPA Report, EMSL-LVftffpress.
Serf's*	A°sesamnterms in m
FOR FURTHER INFORMATION
For copies of the ASSESS program, refer
to NTIS Order Number PB93-505295,
and contact:
United States Department of Commerce
Technology Administration
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
(703) 487-4650
(703) 321-8547 (FAX)
Telex: 64617
For general questions regarding the use of
ASSESS at a site, contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2270
(702) 798-3146 (Fax)
Techmlogy Support Center fact sheet series « developed <
9 L	Lnnkhmj&ri	^—*
The
Clare L. Qmrtach

-------
Environmental	DeSwrnenf8^ ^	mb™ai2 1£n1
Protection Agency	SSSSgK ,DC 20460	(Revised 1995)
TECHNOLOGY SUPPORT
SEPA
INTRODUCTION
THE RATIONALE
DOCUMENT
HOW HYPERTEXT
WORKS
Hypertext: A
Showcase for
Environmental
Documents
The amount of "required
reading" for those engaged in
hazardous waste site
remediation is overwhelming.
Documents pile up - often
leaving the scientist no option
but to briefly review the
abstract or the executive
summary. Fortunately, there
exists a computer software
tool, hypertext, that allows for
documentation on disk that
can provide all readers/users
with various layers of infor-
mation. The tiered knowl-
edge in hypertext makes it
ideal for experts in the field of
the publication who can scan
through the general informa-
tion and concentrate on a
particular section. It is also
suited to the novice in the
document's area who can
access highlighted areas for
in-depth definitions of unfa-
miliar terms, full-screen
presentations of tables and
figures, and references to
ancillary works.
Hypertext is an easy-to-use,
timesaving reading tool for
the overburdened scientist.
The ability to read an elec-
tronic book helps each reader
optimize the information-time
ratio.
Scientists at the CRD-LV
have used hypertext on a
frequently used document, "A
Rationale for the Assessment
of Errors in the Sampling of
Soils" by J. Jeffrey van Ee,
Louis J. Blume, and
Thomas H. Starks. The
original hardcopy document
is about 60 pages long, and
contains 4 figures and 8
tables. The document also
contains several formulas
that may be unfamiliar to
many users. The hypertext
version fits on a floppy disk,
keeps general information
"hidden" unless if s requested
by a novice user, and high-
lights frequently used tables
for easy access.
Hypertext can be applied to
any document that exists in
digital form. The level of
hypertext a document needs
depends on the complexity
and length of the original
document and the anticipated
expertise of the reading
audience.
The Rationale mentioned
above addresses the com-
plexity of the sampling and
analysis of soils for inorganic
contaminants from experi-
mental design to the final
evaluation of all generated
data. Sources of error
abound but they can be
successfully mitigated by
careful planning or isolated
by intelligent error assess-
ment. Error can be either
biased or random. Biased
error is indicative of a sys-
tematic problem that can
exist in any sector of soils
analysis, from sampling to
data analysis. The first step
in analysis of variability is to
establish a plan that will
identify errors, trace them to
the step in which they
occurred, and account for
variabilities to allow direct
corrective action to eliminate
them.
Error assessment should be
understood by the field
scientist and the analyst. To
implement the ideas in the
Rationale document and aid
scientists in the estimation
mid evaluation of variability,
the CRD-LV has developed a
computer program called
ASSESS. By applying
statistical formulas to quality
assurance data entered,
ASSESS can trace errors to
their sources and help
scientists plan Mire studies
that avoid the pitfalls of the
past.
Scientists at the CRD-LV
took the disk containing the
Rationale document and
extracted sections such as
the Table of Contents, tables,
figures, and certain equations
and formulas. These sec-
I in the new hypertext
version. Then, throughout
the document, certain words
and phrases were highlighted
so definitions can be ac-
cessed by a keystroke.
When a reader receives a
hypertext document on disk,
he or she can look at the
Table of Contents and decide
which sections to read. By
selecting, for example, the
section entitled "background",
02550(91

-------
HOW HYPERTEXT
WORKS (Continued)
BRIDGE TO ASSESS
ADVANTAGES AND
LIMITATIONS
HARDWARE
REQUIREMENTS
/
o
o

echnology ^
support 0
Project h;
the reader can be briefed on
the scope of the document.
A term within the Background
section, e.g., "representative"
may be highlighted. Readers
wishing the definition of
"representative" as used in
this document may get an
immediate clarification. In
traditional (linear) hardcopy
documents, a reader must
either wait for the definition to
be clarified in text or seek an
external definition through
outside reference materials, 1
The Rationale document is
the basis for an CRD-LV
environmental software
program called ASSESS.
The philosophy and statistical
background in the document
is exercised practically with
ASSESS, which is also
available on disk. The
hypertext version of the
Rationale document prepares
the reader to use ASSESS
and also serves as a physical
link to the program. The last
item on the Rationale docu-
ment hypertext menu is
"ASSESS". After becoming
familiar with the concepts in
the document, the user may
select "ASSESS" to begin to
use the software.
This hypertext linkage of two
or more documents or
programs can simplify and
clarify many software applica-
tions for novice users. By
providing ASSESS users with
the technical background In I
its development and Ratio-
nale document readers with a
viable program, hypertext
serves all levels of users in
error-tracing in the complex
application of soil sampling.
Increased availability of
computer workstations and
the development of user-
friendly programs have made
hypertext an almost unquali-
fied bonus to busy readers/
users. Hypertext is easily
and effectively used for:
acronyms and abbreviations,
terms and phrases, tables
and figures, graphics, formu-
las and references.

Advantages
Limitations
• Streamlined and non-
interruptive
• Linkage to other hypertext
documents
• Time-saving for expert;
instructional for novice
• Availability of computer
with appropriate hardware
• Some computer literacy
required
¦

Hardware requirements for
using this hypertext package
are:
• IBM PC (or compatible)
• 1.2 MB floppy disk drive,
51/4" (or 31/2" DD or HD)
• Minimum graphjt^ hard-
ware card, monochrome
display with graphics'
capabilities, VGA and EGA
• Minimum $0 K RAM
• Math coprocessor chip is
recommended but not
required
Text, ConText, and HyperText; Writing with and for the Computer, E. Barrett, ed., The MIT
Press, 1988.
van Ee, J. J-.J- J- Blume, and T. H. Starks, A Rationale for the Assessment of Errors in the
Sampling of Soils, EPA Report, EPA/600/4-90/013, May 1990.
FOR FURTHER INFORMATION
For mom details on Hypertext and the
Rationale document contact:
Mr. J. Jeflray van E«
LIS. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 788-2367
For information about the Technology Support
Center at JCBD-LV, contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(7?® 798-2270
(702) 798-3146 (Fax)
The
Clare i

Las Vegas-

-------
&EPA
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
July 1993
(Revised 1995)
TECHNOLOGY SUPPORT
Scout: A Data
Analysis Program





! < >>v in i

	

-
\ 'i *
t	—	1
n

INTRODUCTION
FEATURES/
SPECIFICATIONS
The complexities of correct
data interpretation challenge
environmental scientists
everywhere. Environmental
software packages have
been developed to address
the various needs of data
analysts and decision mak-
ers. One frequent need is for
the reliable determination of
outliers in a data set. Scout
is a program developed to
identify multivariate or
univariate outliers, to test
variables for lack of normal-
ity, to graph raw data and
principal component scores,
and to provide output of the
results of principal compo-
nent analysis. Scout pro-
vides interactive graphics in
two and three dimensions.
There are many advantages
of a graphical display of data
in a multidimensional format:
it allows a quick visual
inspection of data, it accentu-
ates obvious outliers, and it
provides an easy means of
comparing one data set with
another. Scout has the
flexibility to allow viewing and
limited editing of a data set.
Scout features on-line help,
with a "built-in" users guide.
Scout is a valuable addition
to the library of environmental
software packages available
from the CRD-LV.
Scout is a public domain,
Turbo Pascal program that is
user friendly and menu
driven. Scout reads ASCII
data files that are in Geo-
EAS format. The first line of
a Geo-EAS data file is a
comment line, generally used
to describe the origin of the
data. The second line of the
file must contain the number
of variables - always a
number greater than or equal
to 1 and less than or equal to
48. The next lines contain
variable names in the first 10
columns and the associated
values in the next 10 col-
umns. Scout is compatible
with most IBM personal
computers that have an EGA,
VGA, or Hercules graphics
system. Scout will run with or
without a math co-processor,
but this feature is preferred
for handling floating point
calculations. A fixed disk
drive is strongly recom-
mended because Scout
performs many transfers
between memory and disk
during execution. On-line
help is available throughout
Scout and the user can
access it by selecting the
"System" option in the main
menu and then selecting
"Information".
MENUS
There are five menus in
Scout: file management,
data management, outliers,
principal components analy-
sis, and graphics.
After the introduction screen,
the user should choose the
"File Management" option on
the main menu. This option
allows the user to load the
Scout date file or read an
ASCII data file and to access
various subdirectories of
data. Scout saves data files
in two formats: binary and
the Geo-EjEAS ASCII format.
Scout has the ability to
search for file names, includ-
ing wild cards. The current
search string is printed at the
top of the window. Other
options in this area include
"Write ASCII Data File" for
saving the Scout file and
"Merge Two Data Files" for
combining two files into one.
The second men u is "Data
Management" which includes
options for editing data,
variables, and observations.
This menu also displays
summary statistics, such as
mean, standard deviation,
and variance. Additionally,
there is a "Transform" option
which allows the user to test
each variable for lack of
normality, based on the
Kolmogorov-Smirnov test at
the five percent significance
level. The critical value, test
statistic, and apparent
conclusion are displayed.
The Anderson-Darting test is
also performed and a hori-
zontal histogram Is displayed
at the bottom of the screen.
Menu three is "Outliers",
which applies two powerful
tests for discordancy to the
data: the (Mahalanobis')
generalized distance, and the
(Continued)
20STEX93

-------
MENUS (Cont)

s
Mardia's multivariate kurtosis
test. After selecting "Outli-
srs", the user can tell Scout
which variables to test, or use
the default wherein Scout
tests all variables. The user
must then decide to use the
generalized distance test or
Mardia's kurtosis. If a large
proportion of the data is
identified as discordant, the
user should be cautious that
the problem may be due to
lack of multinormality. The
outlier report may be dis-
played, sent to a file, or
printed. By selecting "Causal
Variables" the user can test
each variable for its contribu-
tion to the discordant nature
of the outlier. This option can
trace some independent
errors, such as typographical
or transcription errors.
The fourth menu is "Principal
Component Analysis? which
allows the user to select the
variables to be used and to
display covariance or correla-
tion. By choosing the "View
Components" option, the user
can view the eigenvectors
and eigenvalues of the PCA.
Scout will prompt the user to
specify whether or not to
include previously deter-
mined outliers. The user can
graph the component scores,
which are products of the
eigenvectors and the stan-
dardized observation vectors.
A "Transform Data" option is
available to change the data
in memory from observations
to component scores.
The fifth, and final, menuis
"Graphics" which features
two graphics systems: two-
dimensional and three-
dimensional. The two-
dimensional system is used
to display scatter plots and
x-y plots. The three-dimen-
sional system is used to
display three variable plots,
which can be rotated to
illustrate the added dimen-
sion. The user can modify
graph colors and shapes.
Graphics screens may be
saved by writing to a file on
disk. The user can change
the size of the graph by
zooming in or out using the
V or "-"keys. The four
arrow keys are used to rotate
the graph. The left and right
arrows rotate the graph
around the Z axis. The up
and down arrows rotate the
graph around an imaginary
horizontal axis that passes
through the origin. Another
feature, "Search Observation
Mode", is available and
allows users to identify the
individual observations
shown on the graph.
REFERENCES
nhamometrics: A Textbook. Massart, D. L„ B. G. M. Vandeginste, S. N. Deming, Y. Michotte,
and L. Kaufman, Volume 2 in the Series "Data Handling in Science and Technology",
B. G. M. Vandeginste and L. Kaufman, eds., Elsevier, Amsterdam, the Nether$n&, 1988.
Garner, F. C., M. A. Stapanian, and K. E. Fitzgerald, Finding Causes of Outliers in Multivariate!
Data, J. Chemometrics, in press.
FOR FURTHER INFORMATION
For copies of the Scout program, refer to NTIS Order Number PB93-505303, and contact:
^ ")/•
^ Technology "55;
8 Sw°,t o
United States Department of Commerce
Technology Administration
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
For additional technical information about
Scoilt, contact:
Dr. George Flatmart
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2628
(703) 487-4650
(703) 321-8547 (FAX)
Telex: 64617
Forifxlormation about the CRD-LV
Technology Support Center, contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
tas Vegas, NV 89193-3478
(702)798-2270
(702) 798-3146 (Fax)
The Techml&Juppert Center fact theet smite is developed and written by Clare L Gerfach, Lockheed
EnvironmmmMfatems &7echnologies Company, Las Vegas.

-------
&EPA
INTRODUCTION
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
July 1993
(Revised 1995)
TECHNOLOGY SUPPORT
Geo-EAS: Software
for Geostatistics
The Characterization Re-
search Division in Las Vegas
(CRD-LV) can meet the
needs of scientists who work
with spatially distributed data.
The complexity of contami-
nant distribution and migration
at hazardous waste sites
requires a mathematical
method that is capable of
interpreting raw data and
converting them to useful
information. Geostatistics
began in the mining industry
and has grown to include
applications ranging from
microbiology to air monitoring.
Though the application of
geostatistics is crucial to the
delineation of buried contami-
nants, not every field scientist
can be expected to develop
customized geostatistical
algorithms for individual sites.
Geostaticians at the CRD-LV
developed a software pack-
age, Geo-EAS in 1988. The
current version, Geo-EAS
1.2.1, was released in 1990.
This program offers the
environmental scientist an
interactive tool for performing
two-dimensional geostatistical
analyses of spatially distrib-
uted data.
THE METHODOLOGY
Geostatistical methods are
useful for site assessment
and monitoring where data
are collected on a spatial
network of sampling loca-
tions. Examples of environ-
mental applications include
lead and cadmium concentra-
tions in soils surrounding
smelters, and sulfate deposi-
tion in rainfall. Kriging is a
weighted moving average
method used to interpolate
values from a data set onto a
contouring grid. The kriging
weights are computed from a
variogram, which measures
the correlation among sample
values as a function of the
distance and direction be-
tween samples.
Kriging has a number of
advantages over other inter-
polation methods:
Smoothing
Kriging regresses estimates
based on the proportion of
total sample variance ac-
counted for by random noise.
The noisier the data set, the
less representative the
samples and the more they
are smoothed.
Declustering
The kriging weight assigned
to a sample is lowered to the
degree that its information is
duplicated by highly corre-
lated samples. Thishe/ps
mitigate the impact of
oversampling hot spots.
Anisotropy
When samples are highly
correlated in one direction,
kriging weights will be greater
for samples in that direction.
Precision
Given a variogram represen-
tative of the area to be esti-
mated, kriging will compute
the most precise estimates
from the data.
Estimation of the variogram
from sample data is a critical
part of a geostatistical study.
Geo-EAS is designed to
make it easy for the novice to
use geostatistical methods
and to leam by doing. It also
provides sufficient power and
flexibility for the experienced
user to solve practical
problems.
EQUIPMENT
REQUIREMENTS
Geo-EAS was designed to
run under DOS on an IBM,
PC, XT, AT, PS2, or compat-
ible computer. Graphics sup-
port is provided for Hercules,
CGA, and EGA. At least 512
Kb of RAM is required, but
640 Kb is recommended. An
arithmetic co-processor chip
is strongly recommended due
to the computationally inten-
sive nature of the programs,
but is not required. Programs
may be run from floppy disk
but a fixed disk is required to
use the programs from the
system menu. The system
storage requirement is ap-
proximately three megabytes.
For hardcopy, a graphic
printer is required. Support is
provided for most plotters.
Design features such as
simple ASCII file formats and
standardized menu screens,
give Geo-EAS flexibility for
future expansion. It is antici-
pated that Geo-EAS will be-
come a significant technology
transfer mechanism for more
advanced methods resulting
from the CRD-LV research
and development programs.
Geo-EAS software and docu-
mentation are public domain,
and may be copied and dis-
tributed freely.
2060EX930DC

-------
MAPS AND MENUS
/_ \
^ I echnotogy
o d> „ z
o >SuPP°rt ©
The Geo-EAS programs use
an ASCII file structure for
input. The files contain a
header record, the number of
variables, a list of variable
names and units, and a nu-
meric data table.
All Geo-EAS programs are
controlled interactively
through menu screens which
permit the user to select op-
tions and enter control pa-
rameters. The programs are
structured to avoid a "black
box" approach to data analy-
sis. Several of the more
complex programs permit the
user to save and read param-
eter files, making it easy to
rerun a program.
The programs DATAPREP
and TRANS provide capabil-
ity for manipulating Geo-EAS
files. Files can be appended
or merged, and variables can
be created, transformed, or
deleted. Transformation
operations include natural
log, square root, rank order,
indicator, and arithmetic
operations.
POSTPLOT creates a map of
a data variable in a Geo-EAS
data file. Symbols represent-
ing the quartiles of the data
values or the values them-
selves are plotted at the
sample looations.
STAT1 computes univariate
statistics, such as mean and
standard deviation, for vari-
ables in a Geo-EAS data file,
and creates histograms and
probability plots.
SCATTER and XYGRAPH
both create x-y plots with
optional linear regression for
any two variables in a Geo-
EAS file. SCATTER is useful
for quick exploratory data
analysis, while XYGRAPH
provides additional capabili-
ties such as multiple y vari-
ables, and scaling options.
PREVAR creates an interme-
diate binary file of data pairs
for use in VARIO, which com-
putes and displays plots of
variograms for specified dis-
tance and directional limits.
Variogram models can be
interactively fitted to the ex-
perimental points. The fitted
model may be the sum of up
to five independent compo-
nents, which can be any com-
bination of nugget, linear,
spherical, exponential, or
Gaussian models. XVALID is
a cross-validation program
which can test a variogram
model by estimating values at
sampled locations from sur-
rounding data and comparing
the estimates with known
values.
KRIGE provides kriged esti-
mates for a two-dimensional
grid of points. A shaded map
of estimated values is dis-
played and a Geo-EAS file of
kriged grid results is gener-
ated.
CONREC generates contour
maps from a gridded Geo-
EAS data file, usually the
output from KRIGE. Options
are provided for contour inter-
vals and labels and degree of
contour line smoothing.
REFERENCE:
PressS'ffew York ?989 Srivastava'An fntr°duction to Applied Geostatistics, Oxford University
AVAILABILITY:
For copies of Geo-EAS, refer to NTIS Order
Number PB93-504967, and contact:
United States Department of Commerce
Technology Administration
National Technical Information Sen/ice
5285 Port Royal Road
Springfield, VA 22161
(703) 487-4650
(703) 321-8547 (FAX)
Telex: 64617
FOR FURTHER INFORMATION:
For information about the Technology
Support Center at CRD-LV, contact:
Mr. Ken Brown, Director
Technotogy Support Center
U.S. Environmental Protection Agency
'National Exposure Research Labora-
tory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2270
(702) 798-3146 (Fax)
The
Clare L
e L. (Mrtach, Lockheed Environmental Systems & Technologies Company,
Las Vegas.

-------
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
July 1993
(Revised 1995)
TECHNOLOGY SUPPORT
&EPA
INTRODUCTION
Geophysics
Advisor
Expert System
I ,	. I

An CRD-LV


Environmental


oOftlAMI 6
Program

I 		 I
I «- «- ¦ 1 1
The Characterization Re-
search Division in Las Vegas
(CRD-LV) is concerned with
the selection of correct
monitoring methods. Some-
times the best technique is
not easily discernible. This is
particularly a problem in
sampling and monitoring
complex matrices, like soil
and sediment, and when
buried structures and plumes
are hidden from sight. The
characterization and
remediation of a hazardous
waste site involves several
disciplines, from experimental
design to analytical protocol.
Individuals who decide upon
methods and who are
responsible for approving
contractor suggestions need
an easy-to-use text or
computer program that will
guide them in expensive and
decisive actions.
The decision to use geo-
physical methods and which
geophysical method to use is
a challenge to site managers.
The CRD-LV, in cooperation
with the U.S. Geological
Survey, has developed an
expert system, Geophysics
Advisor, to aid these person-
nel in critical decisions about
geophysical methods that
may impact the quality and
reliability of their data. This
program is built on a founda-
tion of expertise in applying
geophysical methods to
complex hazardous waste
sites. The current version,
Geophysics Advisor 1.0, is
designed to meet the needs
of non-geophysicists to assist
and educate them in their
interaction with geophysi-
cists. It is not intended to
replace the expert advice of
competent geophysicists.
THE PROGRAM
Geophysics Advisor 1.0 asks
questions about the site,
cultural noise, and the
contamination problem. The
program builds upon the
user's answers to early
questions and poses subse-
quent questions on this basis.
At the end of the run, the
program will indicate any
inconsistencies in the user's
responses. The user may
then return to specific ques-
tions and consider changing
the answer.
The program considers
several geophysical methods:
•	electromagnetic induction
•	resistivity
•	ground-penetrating radar
•	magnetic
•	seismic
•	soil gas
•	gravity
•	radiometric
Geophysics Advisor recom-
mends the. type or types of
geophysics that will most
likely Jit 4he site requirements
for determining the location
of contamination and provid-
ing site characterization.
The program will also tell the
user if the use of geophysics
is not suitable for the site. A
relative numerical ranking of
the various methods is
shown on screen, indicating
the degree of superiority of
one method over another.
Methods are also catego-
rized as "recommended,"
"not recommended," or
"uncertain of effectiveness."
Additionally, Geophysics
Advisor tells the user why the
various methods will
or will not work at the site.
Geophysics Advisor allows
the user to make soft re-
sponses such as "maybe"
and "don't know" so novice
(Continued)
20S9EX93

-------
THE PROGRAM
(Continued)
AVAILABILITY
users or those lacking
specific knowledge about the
site can access some of the
power of the program. The
user will be asked about soil
type, cultural noise, contami-
nant identity and level, the
presence of underground
tanks or drums, and the
distance between various
buried items.
If a site is extremely complex,
it is recommended that the
user divide the site into
several subsite problems.
The program can be run for
each subsite.
Geophysics Advisor is a
public domain program
written to run on any IBM-PC-
DOS compatible computer. It
is written in True Basic and
requires 512 K memory when
the operating system is
included.
Geophysics Advisor is
available to all Agency users,
free of charge, upon receipt
of a pre-formatted 31/2" or
51/4" floppy disk. For copies
of Geophysics Advisor, or for
consultation with an CRD-LV
geophysicist, contact:
Dr. Aldo Mazella
U.S. Environmental Protec-
tion Agency
National Exposure Research
Laboratory
Characterization Research
Division
P.O. Box 93478
Us Vegas, NV 89193-3478
(702) 798-2254
REFERENCES
Introductory:
Benson, R. C., R. A. Glaccum, and M. R. Noel, Environmental Monitoring Systems Laboratory!
Las Vegas. Geophysical Techniques for Sensing Buried Wastes and Waste Migration, U.S.
EPA. 1982.
More Advanced:
Telford, W. M., L. P. Geldart, R. E. Sheriff, and D. A. Keys, Applied Geophysics, Cambridge
University Press, 1976.
User's Guide:
Olhoeft, G., Geophysics Advisor Expert System, EPA Project Report EPA/600/4-89/023,1989
.Q/tf'°/V
/_r \
5 Technology ^
o d> , z
o 3uPP°rt o
v"" J
FOR FURTHER INFORMATION
For information about the Technology
Support Center at the CRD-LV, contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
LasVegas,NV 89193-3478
(702) 798-2270
(702) 798-3146 (Fix)
For copies of Geophysics Advisor
Expert System, refer to NTIS
Order Number PB93-505162
and contact:
United States Department of Commercj
Technology Administration
National Technical Information Services
5285 fort Royal Road
.Springfield, VA 22161
(703) 487-4650
(703) 321-8547 (FAX)
Telex: 64617
The Technology Support Center fact sheet series is developed and written bv
Clare L Gerlach, Lockheed Environmental Sytems & Technologies Company, Las Vegas.

-------
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
July 1991
{Revised 1995)
TECHNOLOGY SUPPORT
f/EPA
INTRODUCTION
CADRE: A Data
Validation Program
J
The Characterization Re-
search Division in Las Vegas
(CRD-LV) has developed a
computer software system to
aid environmental scientists
and data analysts in the
evaluation of data generated
by the Contract Laboratory
Program (CLP). This system,
CADRE (Computer-Aided
Data Review and Evaluation)
assists in the validation of
results from various CLP
methods.
CADRE provides data
analysts with a quick and
reliable method for examining
data that will be used for
decision making at hazard-
ous waste sites. The pro-
gram automates the phases
of data validation that involve
electronic-format data. The
data validation-process
involves comparison of
quality control (QC) indicators
used in the analysis with pre-
established data quality
criteria. Non-compliant data
are qualified with appropriate
codes to indicate the severity
of the defect. The final
assessment of the data is
made by the data reviewer,
using the information pro-
vided by CADRE.
Examples of QC parameters
that are checked by CADRE
are: holding time, blanks,
calibration, and precision.
FEATURES
CADRE can read data in
several CLP electronic
formats. It checks for data
completeness, and allow the
user to edit data. After the
validation is complete,
CADRE reports the results.
CADRE can be customized by
the user to validate data
collected using several
methods in the CLP. Users
can configure CADRE to
examine different compounds,
alternate quantitation limits, or
varying QC parameters.
Another customization of
CADRE involves changing
data validation criteria to
meet the needs of a modified
method. The user can
choose, for example, to allow
a longer holding time if the
compound of interest is
unlikely to volatilize or
degrade. The ability to
modify CADRE'S specific
data quality codes provides
the user with greater flexibility
and responsibility.
To protect the data from
tampering and from human
error, a layered security
system allows each user
access to the program
features he or she needs.
The program blends ease of
use with a sophisticated
screen system. Knowledge of
data validation rationale and
microcomputer operation are
recommended for the effec-
tive use of CADRE. A user's
guide, training courses, and
technical user support are
available from the CRD-LV.
CLP ORGANIC
VERSION
The CLP ORGANIC version
of CADRE evaluates data
from CLP analysis of volatile,
semivotatite, and pesticide
compounds. Volatile and
semivolatile organic com-
pounds are analyzed by gas
chromatography/ mass
spectrometry (GC/MS).
Pesticide analysis is a GC
method.
CLP ORGANIC CADRE can
be customized to evaluate
modified versions of these
routine analyses. It can use
alternate data validation
criteria selected by the ueer.
Data can be read by CLP
ORGANIC CADRE from the
CLP Analytical Results
Database (CARD) or from
Agency standard format files.
Checks performed by
CADRE include:
quantitation limits
holding time
GC/MS tuning
calibration
internal standards
system performance
surrogate recovery
matrix spike recovery
precision of duplicates
contamination of blanks
0882EX91

-------
QUICK
TURNAROUND
METHOD VERSION
The Quick Turnaround
Method (QTM) version of
CADRE reviews data ob-
tained by the QTM methods.
There are QTM methods
available for VOC, PAH,
phenols, pesticides, and
PCB. These methods are
based on the need for fast
extraction and chromato-
graphic analysis within
2 days. For speed and
simplicity, QTM CADRE
works in conjunction with
other software for electronic
data transmission from the
laboratory to the user through
the Agency communications
network.
QTM CADRE is completely
automated. The data re-
viewer needs only to set up
the system and interpret the
reports.
ADVANTAGES AND
LIMITATIONS
HARDWARE
REQUIREMENTS

'
echnolagy ^
Z
upport 0
The use of computerized
data evaluation is changing
the workplace for many data
reviewers. The automation of
routine checks will give the
individual more time to
thoughtfully interpret the
results.
It is anticipated that in-
creased accessibility of
computer hardware to
personnel will lead to greater
demand for programs like
CADRE that will streamline
routine work. Currently,
CADRE is being developed
for inorganic methods.
Advantages
Limitations
Fast, complete, and
consistent data validation
Easy customization for
modified methods
Reduction of human error
Automated report
generation
• Requires availability of
powerful computer for
efficient use
• Reviewer judgement
needed for some decisions
• Available for CLP organic
and QTM methods only
• Needs complete data set in
electronic format
Hardware requirements for
using CADRE are:
• IBM PC (or compatible)
• MS-DOS (or equivalent)
• Hard disk drive
• 640 K RAM
A math coprocessor chip is
recommended but not
required. For easy use, a
mouse pointer is
recommended.
REFERENCE
Simon, A. W., J. A. Borsack, S. A. Paulson, B. A. Dsaeon, and R. A. Olivero, Computer-Aided
Data Review and Evaluation: CADRE CLP Organic User's Guide, U.S. EPA, June 1991.
FOR FURTHER INFORMATION
For further information on CADRE,
contact:
Mr. David Eng
U.S. Environmental Protection Agency
1235 Jefferson Davis Highway
Arlington, VA 22202
(703)603*8827
For information about the Technology Support
Center at CRD-LV, contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2270
(702) 798-3146 (Fax)
The Technology Support Center fact sheet series is developed and written by
Clare L. Gerlach, Lockheed Environmental Systems & Technologies Company,
Las Vegas.

-------
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
October 1993
(Revised 1995)
TECHNOLOGY SUPPORT

ARC/INFO
Concepts
and
Terminology
Introduction
The U.S. EPA uses geo-
graphic information systems
(GIS) technology to obtain
reliable spatial information
from layers of descriptive
data. GIS provides methods
for the management, display,
manipulation, and analysis of
geographic data, such as
topological information,
transportation routes, geopo-
litical boundaries, and
waterways.
The Characterization
Research Division in Las
Vegas (CRD-LV) is the
EPA's center for research
and development for GIS
technology. As such, it
demonstrates the applicabil-
ity of GIS to various environ-
mental scenarios, including
Superfund and RCRA site
characterization and the
Environmental Monitoring
and Assessment Program
(EMAP).
Currently, the EPA uses
ARC/INFO, a full-featured
GIS software that follows a
geographic toolbox ap-
proach. There are distinct
tools for modeling and
feature manipulation for each
type of geo-dataset. Some
tools operate on entire
databases, others on entire
geo-datasets, and others on
individual features (1).
The Architecture
Map library tools define and
manage entire GIS data-
bases centrally. These
tools control the access,
modification, and update of
each theme within a map
library. Geo-dataset tools
operate on entire datasets
and can be categorized as
translation, edit, analysis,
and query/display tools.
Digital dataset conversion
into an ARC/INFO geo-
dataset is handled by a
large set of translation tools.
Digitize/ecHt tools support
creation of new geo-
datasets including topology,
locational data, attribute
entry, and data verification.
Analysis tools perform
spatial analysis functions on
one or more datasets.
Examples of these analysis
tools are:,,
Coverage overlay
Theissen polygon
generation
Surface and contour
generation
Buffer zone generation
Network allocation
Map projection and
coordinate transformation
Rubber sheeting
Feature generalization
Feature selection and
aggregation
Arithmetic and logical at-
tribute combination
Proximity and dispersion
analysis
The query/display tools
scale and position map data,
associate cartographic
symbols to map features,
and display, identify, and
control map features based
on their attributes. Feature-
level tools operate on
individual features within a
coverage.
ARC/iNFO is structured so
that similar types of tools
are organized within soft-
ware modules that perform
similar sets of functions.
Table 1 lists the main
functions of each subsystem
of ARC/INFO.
ARC/INFO has an embed-
ded language processor that
is machine independent,
providing a consistent way
to control the user environ-
ment, command processing,
and application develop-
ment.
MhMMt

-------
Table 1. ARC/INFO Subsystems
Module Name
Main Function
Geographic
Concepts in GIS
Arc
Arcplot
Arcedit
COGO
TIN
Grid
Librarian
Network
Start other modules, data conversion, analysis and manipulation, coordinate
transformation, topology generation, attribute automation, database
construction, plotting, coverage and workspace management
Vector and raster data display and query. Spatial analysis
Vector data editing and manipulation
Coordinate geometry
Surface generation
Raster processing and modeling
Centralized spatial database management
Linear modeling and distribution analysis
There are six for concepts
that are pertinent to the
application of GIS technology
to environmental studies:
•	Geographic data represen-
tation
•	Topology
•	Maps as the basis for GIS
data input and output
•	Data resolution
•	User interface
•	Relational database
management systems
^ "Technology
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The basic unit of data man-
agement in ARC/INFO is the
geo-dataset, which includes
the coverage, grid, and
triangulated integrated
network (TIN). Each geo-
dataset uses an associated
data model to define
locational and thermic
attributes for map features.
The data model (vector or
raster based) has its own set
of geo-processing and
modeling tools.
Polygons, lines, points,
nodes, and annotations are
features which, when
associated with thematic and
locational attributes, can be
used to represent many
types of mapped information.
The integration of various
data types is the strength of
GIS technology. Using
layers of data, researchers
are able to generate informa-
tion that realistically defines
conditions at a site. This
information is a key to
correct decision making at
Superfund and RCRA sites.
REFERENCES
(1) Morehouse, S. The Architecture of ARC/INFO, ARC News, 12 (2). 1990
FOR FURTHER INFORMATION
For information on GIS Technology research and
development at the CRD-LV, contact:
Mr. Mason Hewitt
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2377
For tolocmation about the Technology
Support Center at the CRD-LV, contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 7.88*2270
(702) 798-3146 (Fax)
The Technology Support Center fact sheet series is developed by Clare L Gerlach,
Lockheed Environmental Systems & Technologies Company, Las Vegas.

-------
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
October 1993
(Revised 1995)
TECHNOLOGY SUPPORT
&EPA
Accessing
Geographic
Information
Systems
Technology
Introduction
Geographic Information
Systems (GIS) technology
has been used by the U.S.
Geological Survey and by
state and municipal govern-
ments for years. Recently,
its application to environ-
mental studies has become
apparent and growing
numbers of environmental
scientists are able to access
the power of GIS.
The user is able to analyze
data, query the system for
more information, and obtain
detailed databases upon
which accurate site assess-
ments can be made. Ques-
tions about the destination of
effluents, the location of
population groups, and other
environmental impact
determinations can be made.
Its power is in its ability to
relate attribute data to
cartographic features. This
allows data analysis that can
be used by decision-makers
to guide the course of an
investigation. This strength
makes it particularly appli-
cable to environmental
investigations, where
decisions must be based on
complexities of source,
extent, and matrix.
GIS can incorporate data-
bases from the U.S. Geologi-
cal Survey, aerial photo-
graphic information, mea-
surement results, and data
from municipalities and
utilities. Further, it can
incorporate historical data-
bases for comparisons. By
overlaying the digitized
information, GIS scientists
can produce accurate and
informative maps of a
location. GIS represents
data as points, lines, or
polygons. Types of data
input include transportation
features, geopolitical bound-
aries, streams, and topogra-
phy. This integrated ap-
proach is particularly perti-
nent to the characterization
of hazardous waste sites.
Man-made structures can be
superimposed upon natural
features to provide the
investigator with a complete
picture of an area of environ-
mental interest. By using
GIS, scientists can identify
areas that require closer
screening for hazardous
components.
The Characterization Re-
search Division in Las Vegas
(CRD-LV) was the first EPA
laboratory to use GIS tech-
nology in environmental
applications. Now, CRD-LV
is a center for GIS research
and development and
customizes GIS use to the
needs of the EPA Regions
and Program Offices. There
is a GIS applications center
in each Region with irv-house
experts to help Remedial
Project Managers, Site
Assessment Managers, and
On-Scene Coordinators.
The power of GIS technology
enhances the ability of
environmental decision-
makers to assess the extent
of contamination. GIS uses
an increasing amount of
information that is pertinent
to the characterization and
remediation of hazardous
waste sites.
"Hie reverse side of this
Technology Support Center
Fact Sheet gives GIS con-
tacts at the CRD-LV and at
each of the Regions.
2053ex93odc.fs

-------
REFERENCE
FOR FURTHER INFORMATION
A summary of G1S Support to Superfund, a U.S. EPA, EMSL-LV report, EPA/600/X-93/062,
1993.
EMSL-LV publications Tech Memos 1-5
For information about the CRD-LV GIS Center for Research and Development and for copies
of the documents listed above: write to:
Mr. Mark Olsen
U.S. EPA
CRD-LV
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-3155
Mr. Mason Hewitt
U.S. EPA
CRD-LV
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2377
For information about the Technology Support Center at CRD-LV, contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2270
(702) 798-3146 (Fax)
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1	I ©chnology ^
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For GIS assistance at the Regional level, contact:
Region 1
Greg Charest
617-565-4528
Region 2
George Nossa
212-264-9850
Region 3
David West
215-597-1198
Region 4
James Bricker
404-347-3402
Regions
Noel Kohl
312-886-6224
Regions
David Parrish
214-655-8352
Region 7
R. Lynn Kring
913-551-7456
Region 8
Bill Murray
303-294-1994
Region 9
MarkHnmry
415-744-1803
Region 10
Ray Peterson
206-553-1682
The Technology Support Center fact sheet series is developed by Clam L Gerlach,
Lockheed Environmental Systems A Technologies Company- Las Vegas.

-------
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
October 1993
(Revised 1995)
TECHNOLOGY SUPPORT
Geographic
Information
Systems:
An
Overview
2060GR930DC.FS
The U.S. EPA is interested in
the development and utiliz-
ation of sophisticated tools
for the measurement and
analysis of contamination at
Superfund and RCRA sites.
Geographic Information
Systems (GIS) are systems
where geographic data des-
cribing the earth's surface
are managed; displayed,
manipulated, and analyzed
(1). GIS is able to analyze
spatial data, making it a
powerful tool for the analysis
of the source, extent, and
transport of various types of
contamination.
The Characterization Re-
search Division in Las Vegas
(CRD-LV) is the Agency's
Center for Research and
Development in GIS technol-
ogy. Work Is underway on
the application of GIS to site
characterization al various
Superfund and RCRA sites.
The ability to analyze com-
plex, spatial data makes GIS
technology interesting to a
growing user community
within environmental sci-
ence. Applications include
environmental monitoring,
modeling non-point runoff,
and landscape ecology. The
EPA's Environmental Moni-
toring and Assessment Pro-
gram (EMAP) is tapping into
the many capabilities of GIS
technology as It begins its
long-term evaluation of eco-
logical trends.
The heavy emphasis on
analytical manipulation of
spatial data is the main
characteristic that distin-
guishes GIS from other
technologies like computer-
aided design and electronic
mapping systems. Using
GIS, an analyst is able to
present a complete picture
of a site location, tiering
maps of streams, geo-politi-
cal boundaries, transporta-
tion routes, and topographic
information.
The power of GIS to gener-
ate highly specialized
informational maps makes it
an effective method for
presenting information to
decision makers and to the
public. GIS is capable of
much more than generating
maps and presenting data.
Environmental studies
produce complex data that
are difficult to represent
verbally or visuaHy. Using
GIS, environmental scientists
are able to interpret spatial
data, manage complex
databases, and use layers of
information from various
sources. Based on GIS,
analysts can produce a
realistic and understandable
visual analysis of a hazard-
ous waste site.
20«Xx93odc

-------
Hardware, Software,
and People
GIS systems rely on a
relational database manage-
ment system to provide the
ability to query, manipulate,
and extract geographic
reference and attribute data.
This approach permits
standard statistical manipula-
tions of attribute data, as well
as logical and boolean
queries based on GIS
feature characteristics (2).
Some common analysis
capabilities include measure-
ments, attribute reclassifica-
tion, topological overlay,
connectivity operations,
coordinate transformations,
and surface analysis.
GtS hardware includes the
computer platform and
peripherals. Components
include a terminal to display
graphics, a central process-
ing unit, a digitizer to
manually trace data from
maps, a plotter to write
cartographic output, and a
tape drive to save and
export information. Other
GIS peripherals include
scanners, optical drives, and
image recorders. The trend
is toward workstations and
personal computers that
provide the power arid
performance required by
GIS.
User interface functions
such as menus, scrolling
lists, and other graphic user
interface (GUI) building tools
may be supported by the
language processor.
Applications can be built to
simplify complex tasks,
providing decision support
tools to novice users. Some
GIS language processors
have the ability to access
other programs written in
higher language systems
such as Fortran and C,
using embedded routines to
access common blocks of
computer memory.
There is a growing need for
spatial analysis to be an
integral part of routine data
analysis and decision-
making. To meet this need,
GIS technology is migrating
to the desktops of applied
technologists in fields like
biology, economics, and
environmental science.
Reliability
Digitized data and the
informational maps th?t result
from GIS applications are
only as reliable as the quality
of the data that is input.
Whenever GIS is used for
decision-making, it is impor-
tant to state the confidence
levels of the information.
Some research effort is
underway to represent the
reliability of the data by
subtle differences in the
display characteristics.
REFERENCE
1.	Understanding GIS: The Arc/Info Method. Environmental Systems Research Institute,
Inc., Redlands, CA. 1990.
2.	Geographic Information Systems (GIS) Guidelines Document. Office of Information
Resources Management. U.S. EPA. 1988.
.otfio/v.v
^ "T"	tl
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FOR FURTHER INFORMATION
For further information on GIS Tech-
nology research and development at
the CRD-LV, contact:
Mr. Mark Olsen
U.S. Environmental Protection Agency
National Exposure Research Labora-
tory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-3155
For information about the Technology Support
Center at the CRD-LV, contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 9347S
Us Vegas, NV 89193-3478
(702) 798-2270
(702) 798-3146 (Fax)
The
Lockheed

Vegas.
L. Gerlach,

-------
United States	Office of Research and	October 1993
Environmental	Development	(Revised 1995)
Protection Agency	Washington, DC 20460
TECHNOLOGY SUPPORT
&EPA
Introduction
The GIS
Planning
Process
2079GR83ODC.FC
Planning is an important step
in the characterization of con-
tamination at hazardous
waste sites. Thoughtful plan-
ning early in the process can
save time and money as the
characterization progresses.
The use of geographic infor-
mation systems (GIS) tech-
nology can provide the
analyst with valuable informa-
tion about a site. Because so
much information is available,
it is important that the analyst
ask the right questions and
access pertinent databases.
GIS is a complex tool that
requires planning in many
areas to avoid problems that
can affect the project's out-
come. Scientists at The
Characterization Research
Division in Las Vegas (CRD-
LV) have isolated six areas
essential to the GIS project
planning life cycle.
They are:
•	Define project objectives
•	Identify analytical require-
ments
•	Define data and hardware
requirements
•	Determine data availability
•	Resolve data development
issues
•	Implement project plan
As with any analytical pro-
cess, the quality of the result
is dependent upon the
recognition of the exact
problem and the implemen-
tation of the correct steps in
addressing it. The GIS
software used by the U.S.
EPA is ARC/INFO.
Project Objectives
Defining specific project
objectives reduces wasted
time and effort in the project
planning lifecycle. Project
objectives should encompass
evety aspect of the project,
from data collection and
manipulation to data display
and archival. Not all aspects
of a project are known in their
entirety at the onset of a
project, of course, so project
objectives should be flexible
enough to be customized as
more knowledge of the study
becomes available.
Sometimes very little is
known about the project at
the beginning of the study
and a preplanning data
gathering effort is necessary
to establish the facts.
Analytical
Requirements
Data and Hardware
Requirements
The next step in planning is
the identification of analytical
requirements. The defined
analytical requirement will be
used to specify more exact
standards for database data
quality, resolution, and scale.
This stage of the GIS plan-
ning process requires the
input of project staff and GIS
specialists. It is important
that the project staff commu-
nicate their exact needs to
the GIS experts. After the
requirements are estab-
lished, program management
staff should prioritize the
needs and establish measur-
able data quality objectives
to meet them.
GIS systems are used to
organize field data in a
spatial context that allows
decision makers to make
informed choices as the
study progresses.
After the analytical require-
ments are established, it is
possible to compile a detailed
list of data and hardware
needs. A data matrix of
needs and sources is helpful
in this planning step. At this
stage it is useful to consider
the attribute information
required for analysis,
minimum data resolution
and scale, data input and
output formats.
Hardware requirements
should be specified at this
point. Some key consider-
ations are the integration of
data from other sources,
data display needs, and the
types and functions of the
user interface. ARC/INFO
supports many different
types of graphic terminals
and their plotters. Data
visualization is affected by
the sensitivity and resolution
of graphics terminals and
printers.
2078«83odc

-------
Data Availability
Data Development
Issues
Implementation
The project's analysis
objectives can only be met if
the data is available. The
degree to which GIS data are
available is related to the
resolution, scale, and compi-
lation date required by the
study. Another availability
factor is cost. Data may be
available in the sense of
existing but may be beyond
the cost restrictions of the
particular project. The data
needed for a project will fall
into one of three categories:
data you have, data some-
one else has, and data no
one has.
Data development may be
required to address the data
quality objectives of the
project. At this point, data
must be assessed to ascer-
tain their adequacy. Project
deadlines and data quality
objectives (DQOs) should be
reviewed at this time. The
personnel responsible for
critical decisions should be
involved in this adequacy
review. Key questions
should be asked. Are the
data adequate to meet the
DQOs of the project? Can
defensible decisions be made
based on the data at hand?
Is the data quality sufficient?
Is there enough time to
gather additional data if
necessary?
All aspects of the information
should be evaluated for cost
impact. Cost considerations
may include the acquisition
of data, travel costs, quality
assurance, contractor fees,
and all project management
costs.
The GIS project implementa-
tion phase carries out the
database development and
analysis objectives. The
database design defines the
database structure, its
characteristics, coverage
attribute coding scheme, data
models, and automation
methods. The resulting
design document should
determine if the GIS data-
base meets the project*s
analytical objectives. The
data capture and automation
phase carries out the data-
base design through data
acquisition and integration of
data into the GIS system.
The database design in-
cludes digitizing analog
maps, converting digital data
into GIS format, and correct-
ing and coding data.
Once the database is
complete, a test of the GIS
analysis functions is per-
formed. When the staff are
satisfied with the system's
ability to meet the analytical
requirements of the project,
database production can
begin.
REFERENCE
GIS Technical Memorandum 1; GIS Planning and Data Set Selection, U.S. EPA, EMSL-LV.
¦¦¦
^ "Technology ^
O SiuPPQrt S
FOR FURTHER INFORMATION
For further information on GIS Technology
research and devebpment at the CRD-LV,
contact:
Mr. Mark Olsen
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Us Vegas, NV 89193-3478
(702)798-3155
For information about the Technology
Support Center at the CRD-LV, contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2270
(702) 798-3146 (Fax)
Ia l-'ro|ecl £
The Technology Support Center fact sheet series is developed by Clare L Gerlach,
«^Oqy	Lockheed Environmental Systems & Technologies Company, Las Vegas.

-------
United States
Environmental
Protection Agency
c/EPA
CAPABILITIES
Office of Research and
Development
Washington, DC 20460
September 1992
(Revised 1995)
TECHNOLOGY SUPPORT
Remote Sensing
in Environmental
Enforcement
Actions
The Characterization Re-
search Division in Las Vegas
(CRD-LV) and its Environ-
mental Photographic Inter-
pretation Center (EPIC)
support EPA litigation actions
through remote sensing
technology. In the course of
conducting environmental
analyses EPIC has acquired:
1) a large library of remote
sensing and resource
documentation derived
from archival sources
nationwide. The library
collection includes more than
150,000 frames of imagery
dating from the late 1930s to
the present, covering areas
throughout the United States.
In addition to the imagery,
completed remote sensing
reports and other resource
data such as maps, soil
surveys and cartographic data
are available for documenta-
tion in legal proceedings.
2) a technical staff experi-
enced in the analysis of
imagery in a number of
discipline areas: wetlands,
geology, environmental site
analysis, as well as photo-
grammetry. Over the years
the technical staff has gained
substantial experience in the
analysis of imagery and its
interpretation using modern
computer technology.
3) a modern integrated
system of imagery collec-
tion and analysis equip-
ment. EPIC has a computer
driven analytical stereo
plotter and a digital video
plotter, both of which en-
hance accurate photogram-
metric measurements of
environmentally significant
features. Additionally,
geographic information
systems (GIS) capabilities
permit highly accurate
integration of both spatial and
positional data that can bear
legal scrutiny.
applications to
EPA ENFORCEMENT
ACTIONS
CRD-LV has provided vital
technical support to a variety
of EPA mandated cases.
They include civil and crimi-
nal actions brought by EPA
Regional offices, the National
Enforcement Investigations
Center (NEIC), and the
Offices of Inspectors Gen-
eral.
EPIC has supported general
counsels of various EPA
Regions, U.S. Department of
Justice attorneys, and state
attorney generals offices.
Specific cases have involved
prosecutions brought under
CERCLA, RCRA, Clean
Water Act, and National
Environmental Policy Act. In
almost ail instances, the
actions culminated in out-
comes favorable to EPA
interests. The penalties have
included cost recoveries in
civil proceedings, corporate
fines, and fines and prison
sentences to individuals in
criminal proceedings.
1296EX920DC

-------
SERVICES
EPA/CRD-LV facilities - EPIC
East and West — operate
under conditions of continu-
ous security. Both facilities
are vaulted, and 24-hour
round-the-clock protection is
maintained at each location.
The following are some of the
services provided and
procedures observed in
supporting environmental
enforcement actions.
Acquisition, indexing and
archiving of imagery,
topographic maps and all
photo-derived documents.
Chain-of-custody documen-
tation of imagery, which
records the handling of the
imagery from supplier,
through shipper and in-
house handling, to cus-
tomer receipt.
Certified authenticity of
imagery and product
documents used in
courtroom testimony.
Depositions or affidavits
by expert witnesses,
trained and experienced
in environmental
disciplines.
PRODUCTS
The products provided in
supporting environmental
enforcement actions include:
historical and current imag-
ery, enlarged photographs,
digital and analog remote
sensing products, environ-
mental reports, and mounted
graphical exhibits for court-
room display. The prepara-
tion of photographic and
graphic courtroom exhibits is
under controlled laboratory
conditions and careful
supervision. All graphical
displays can be easily
annotated for full visual effec
in the various litigation or
testimonial forums.
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REFERENCES
Remote Sensing in Hazardous Waste Site Investigations and Litigation TS-AMD-86724;
December 1988 (Revised).
FOR FURTHER INFORMATION
For further information on remote sensing use in environmental enforcement, contact:
Mr. Donald Garofalo
U.S. EPA-Environmental Photographic Interpretation Center
National Exposure Research Laboratory
Characterization Research Division
Building 166, Bicher Road
Vint HHI Farms Station
Warrenton, Virginia 22186-5129
(703)341-7503
For information about the Technology Support Center at CRD-LV, contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2270
(702) 790-3146 (Fax)
The Technology Support Center fact sheet seriea is developed and written by
Clare L. Gerlach, Lockheed Environmental Systems & Technologies Company, Las Vegas

-------
United States	Office of Research and	February 1991
Environmental	Development	(Revised 1995)
Protection Agency	Washington, DC 20460
&EPA
INTRODUCTION
TECHNIQUE
SCOPE
TECHNOLOGY SUPPORT
Topographic
Mapping for
The location, extent, and
historical change in the
nature of hazardous waste
sites is of great importance to
the Environmental Protection
Agency, and can be docu-
mented through the creation
of topographic maps. The
Characterization Research
Division in Las Vegas (CRD-
LV) is the Agency's center for
mapping and related remote
sensing technologies.
Topographic (elevation)
maps are simple, effective,
and graphic tools for record-
ing the quantitative and
qualitative characteristics of
hazardous waste sites.
These maps are most often
created from aerial photo-
graphs and, since national
archives of coverage date
back more than fifty years,
maps can be created that
reflect historical site condi-
tions.
A typical topographic map-
ping project begins with a
request from an RPM to the
CRD-LV Technology Support
Center. The CRD-LV pro-
vides a cost estimate and
arranges for all necessary
geodetic surveys, aerial
photographic overflights, and
map production. No permis-
sion is needed for a flyover,
in addition to basic positional
information about ground
elevation and locations of
objects, maps can serve as
the base for a targeted
sampling grid, or for record-
ing specialized information
such as land disposal activity,
population distribution,
geologic fractures, vegetation
communities, wetlands
delineation, and land use.
so aerial photography is of
particular value in situations
where uncooperative owners
deny intrusive sampling. A
specially calibrated aerial
camera is used to insure
accurate photography for
later use in the map produc-
tion process. Once the film is
developed, it is placed in a
special instrument
When compared with histori-
cal aerial photographs these
maps can provide both
qualitative and quantitative
information on changesin
volume and elevation (e.g.,
last year there was a mound
three times larger than the
present one; or, between
1988 and 1990, there were
100,000 cubic yards of
material placed in the land-
(stereoplotter) which creates
a model of the terrain to
produce a contour map. The
map may be generated as
hardcopy, or in digital form
for later use with Geographic
Information Systems (GIS).
The same aerial photographs
can be interpreted to assess
the remediation actions at the
site.
fill). Topographic information
is enteted into ARC4NFO
(the QIS software currently
used by the EPA) for future
referral. The information on
these maps can provide
answers to oriticat environ-
mental questions such as the
probable sources of contami-
nation and the ultimate
destiny of discharges.
1661EX90

-------
ADVANTAGES AND
LIMITATIONS
FUTURE PLANS
Topographic mapping is a
mature technology that is
expanding to meet the needs
of the environmental commu-
nity. Advances in computer
technology and optical
sciences have enhanced
remote sensing capabilities
over the years • and continue
to do so.
Advantage
Legally defensible data
Permanent historical record
Digital or analog format
Geographic relationships are
cleany demonstrated
Quantitative measurements
can be made
Limitation*
Seasonal and weather restric-
tions
Complexity of technology
Remote sensing and map-
ping technologies continue to
develop and hold great
promise for practical environ-
mental usage. The basic
topographic mapping process
is being augmented by a
series of related monitoring
techniques that will provide
new thematic mapping
products. Among these are:
the use of orthophotography
which is hard-copy imagery
corrected to map-qualify
standards; land use/land
cover mapping from satellite
data; and the development of
various digital products in a
Geographic Information
Systems format.
The increased need for
accurate information will
continue to drive remote
sensing and topographic
mapping growth in the 1990s
REFERENCES
U.S. Environmental Protection Agency. Photogrammetric Mapping Program for Hazardous
Waste Sites. An EMSL-LV publication. 1984.
Remote Sensing and Interpretation, Lillesand, T. M., and R. W. Kiefer, especially Chapter 5.
John Wiley and Sons, 1979.
^ "Technology
8 Support q
^ project £•
*^£.ogy

FOR FURTHER INFORMATION
For specific information on topographic mapping, contact:
Mr. Paul Olson
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2288
For further information on technology support, contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2270
(702) 798-3146 (Fax)

-------
f/EPA
INTRODUCTION
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
February 1992
(Revised 1995)
TECHNOLOGY SUPPORT
Remote
Sensing
Support
for RCRA
Since the passage of the
Resource Conservation and
Recovery Act (RCRA), the
U.S. EPA has employed
aerial remote sensing tech-
niques to assess the suitabil-
ity of sites for disposal of
hazardous wastes. Remote
sensing (interpreted aerial
imagery) provides key
information necessary for
RCRA personnel to respond
to problems at waste disposal
sites, to assess the risks of
those sites to their neighbor-
ing communities, and to
evaluate new sites proposed
for the disposal of hazardous
waste. Aerial photography
and other sensor imagery are
the most economic source of
information that is required by
Agency officials for permit
reviews, litigation support,
site operations monitoring,
and general environmental
assessments. Acquisition
and interpretation of aerial
imagery data for this and
other Agency programs are
conducted by the Character-
ization Research Division in
Us Vegas (CRD-LV).
The CRD-LV provides aerial
imagery acquisition and
interpretation support for
hazardous waste site analy-
sis to the Regional offices
and to the Office of Solid
Waste and Emergency
Response (OSWER). Typi-
cal OSWER activities that
have been supported include
emergency response to
hazardous materials release
situations, current site
condition assessments,
historical reviews of site
development, waste site
inventories for large geo-
graphical areas, topographic
mapping of sites, and crimi-
nal and civil litigation under
RCRA. The remote sensing
support provided is typically
paid for by reimbursable
funding from the office
supported.
Remote sensing is a key tool
for addressing RCRA en-
forcement and response
issues. The Environmental
Photographic Interpretation
Center (EPIC), at CRD-LV,
provides:
•	A team of scientists with
the critical skills that are
required for unique environ-
mental/enforcement issues;
•	The applications research
that is necessary to keep
the Agency at the state-of-
the-art and a capability to
transfer this technology to
the Regions; and,
•	The ability to respond
quickly to emergency spills
of hazardous materials.
ENFORCEMENT
REQUIREMENTS
The CRD-LV program also
supports special enforcement
requirements. Once a site
analysis is completed by
CRD-LV and a final report is
produced, it may be several
years before the associated
RCRA case comes up for
litigation. For more that 17
years, the CRD-LV has
contributed to the production
and maintenance of hazard-
ous waste disposal site
image analysis reports and
records. The CRD-LV
program thus provides a
team with an institutional
memory that offers reliable
and consistent support to
enforcement cases through-
out extended litigation under
RCRA. In this role, the CRD-
LV provides support to EPA's
National Enforcement
Investigations Center (NEIC),
to Regional Offices of Crimi-
nal Investigation (OCI's), and
to the Department of Justice.
EPA's attorneys prefer using
a centralized EPA remote
sensing program for criminal
prosecutions. In their opin-
ion, such a program is
sensitive to the security
requirements of enforcement
cases, is involved in fewer
conflicts of interest, uses
proper chain-of-custody
procedures for handling
cameras, film, and photo-
graphs, and develops long-
term working relationships
with the EPA attorneys.
1053EX92

-------
TECHNOLOGY
TRANSFER
ACTIVITIES
EMERGENCY
RESPONSE
CAPABILITY
ENFORCEMENT

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The CRD-LV also provides
technology transfer support
to EPA Headquarters and
Regional program offices in
the form of RCRA training
workshops and technical
advice. This includes send-
ing CRD-LV scientific staff to
the Regions to demonstrate
the use of interpreted aerial
imagery in addressing RCRA
requirements in the Region.
This is an on-going activity
conducted on a regular basis
to ensure that new RCRA
staff are properly informed
and current staff are kept up
to-date with the technologies
EPIC also uses the capability
of the CRD-LV to respond to
emergency requests, usually
in response to hazardous
material release or other
emergencies at waste sites.
These actions provide quick
pictorial information on
conditions at the site. Infor-
mation on the extent and
location of visible spillage,
vegetation damage, and
threats to natural drainage
and human welfare are typical
of the types of information
gathered during emergency
response activities.
EPIC, through its fully opera-
tional photo processing and
image analysis facilities in
Warrenton, VA, and
Las Vegas, NV, is on call to
respond to emergency
situations and prepared to
work around the clock to
process aerial photography,
analyze the film, document
the analysis results, and shi
the results to the requester
as soon as possible.
The Agency has special
enforcement requirements for
civil and criminal litigation
and many of these require-
ments have direct policy
implications. For example,
there are specific security
requirements of EPA criminal
cases, as outlined in the
Federal Rule of Criminal
Procedure 6(e), which
requires protection of grand
jury material. CRD-LV
provides protection of these
materials through the use of
proper chain-of-custody
procedures which is crucial
the success of EPA cases.
FOR FURTHER INFORMATION
For further information about the custom service available through the CRD-LV for RCRA
sites, contact:
Regions 1-5
Mr. Gordon Howard
National Exposure Research Laboratory
Characterization Research Division
(703) 341-7506
FAX (703) 341-7575
Regions 6-10
Mr. PhjL Artoerg
National Exposure Research Laboratory
Characterization Research Division
(702) 798-2545
FAX (702) 798-2692
For Information about the Technology Support Centatat CRD-LV, contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2270
(702) 798-3146 (Fax)
The Technology Support Center fact sheet series is developed and written by
Clare L. Gerlach, Lockheed Ennvironmental Systems & Technologies Company,
Las Vega*

-------
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
October 1991
(Revised 1995)
TECHNOLOGY SUPPORT
&EPA
INTRODUCTION
Wetlands Delineation
for Environmental
Assessment
The Environmental Photo-
graphic Interpretation Center
(EPIC) at The Characteriza-
tion Research Division in Las
Vegas (CRD-LV) provides
current and historical wet-
lands analyses that locate,
characterize, and document
historical dredge or fill
activities in wetlands.
Aerial photographs offer a
synoptic view of wetlands
and their surrounding envi-
ronments and form a perma-
nent record of present and
past conditions. Precise
quantitative measurements
can be derived from aerial
photos that aid field work by
displaying relationships not
readily apparent on the
ground. Uses for extracted
data range from general
regional planning to legally
defensible presentation of
data.
EPIC wetlands analysts tap
years of experience in
photointerpretation of varied
wetlands habitats. Collateral
information on soils, local
hydrology, and vegetation is
always utilized to ensure the
accuracy of the delineations.
Field verification may be
used to enhance the accu-
racy of the delineations.
Aerial measurements of data
can determine loss of wet-
land habitat, length of con-
structed drainage channels,
or other pertinent information.
Various levels and formats of
wetlands delineations are
available as dictated by the
needs of the requester.
Overlays to either aerial
photos or topographic maps
may be produced, or the data
can be converted to digital
form for use within a Geo-
graphic Information System
(GIS).
SCOPE
Wetland/Upland Boundary
Analysis
Determination of a wetland/
upland boundaiy is the
simplest analysis. This level
of analysis is used to locate
wetlands and off-site drain-
age patterns. It is typically
requested for a specific area
surrounding sites and usually
involves the most current
year of photography, but
multiple years can be ana-
lyzed if change detection is
needed.
Detailed Analysis
A detailed wetlands analysis
is requested when informa-
tion is needed on vegetation
types in the wetlands and
deepwater habitats classifica-
tion system developed by
Cowardin et al. (1979) for the
U.S. Fish and Wildlife Ser-
vice. Analyses of single or
multiple years of coverage
are performed.
Section 404 Support
Section 404 of the Clean
Water Act protects wetlands
from unpermitted dredge and
fill activities. Analyses
involve field work using
jurisdictional delineation
procedures. Wetlands are
classified using the full
Cowardin et. al. (1979)
classification system. Two
types of analyses are used in
support of this program.
Enforcement
Court support can be pro-
vided for enforcement cases
where wetlands have been
dredged or filled and no
permit had been issued.
Using historical photographs
and field verification, refer-
ence wetlands having the
same photographic signature,
soils, and hydrology as the
dredged or fitod wetlands are
used to confirm the classifica-
tion of tile filled or dredged
wetlands. Current overflights
of the site are generally
acquired to ascertain current
conditions. To detect
change, at least 2 years of
photography are analyzed.
Area measurements of
wetlands loss and change by
type are calculated using
Geographic Information
Systems software. Should
legal proceedings be re-
quired, graphic displays and
expert witness testimony are
provided.
Advance Identification
In support of the Advance
Identification process of 404,
delineation of wetlands on
overlays of current photo-
graphs or base maps are
available. These studies are
a cost-effective way to
identify wetland habitat in
advanee of permit application
and evaluation.
1H1EXB1

-------
ADVANTAGES AND
LIMITATIONS
FUTURE PLANS
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Historical aerial photographs
are often the only means of
establishing the prior exist-
ence of wetlands for sites
that have been dredged or
filled. Progress in computer
technology has enhanced the
accuracy of both presentation
and measurement of wetland
change detection data and
subsequent transfer to maps.
Advantages
Limitations
• More cost effective than
intense field sampling
• Legally defensible
• Verifies existence of
current or historical wet-
lands
• Detection of change
• Photo coverage of critical
years
• Visibility obscured by snow
cloud cover, and leaf-on
conditions
• Available photography may
exhibit extremes in hydrol-
ogy (drought and flood)
• Lack of photo coverage for
critical years
Remote sensing for wetlands
delineation and mapping is
an expanding field. Improve-
ments in the resolution of
aerial photography and
associated technologies will
expedite the delineation
process. With the introduc-
tion of photogrammetric
instruments into this mapping
discipline, precise planimetric
and volumetric measure-
ments can be performed in
support of EPA needs. By
converting photointerpreted
data into digital format, they
can be combined with data
from diverse sources result-
ing in spatial information
useful for environmental
decision making.
REFERENCES
Cowardin, L. M., V. Carter, F. C. Golet, and E. T. LaRoe. Classification of Wetlands and
Deepwater Habitats of the United States, U.S. Department of the Interior, Fish, and Wildlife
Service, FWS/OBS-79/31,1979.
FOR FURTHER INFORMATION
For further information on wetlands mapping capabilities contact the Environmental Photo-
graphic Interpretation Center at
Regions 1-5
Mr. Gordon Howard
National Exposure Research Laboratory
Characterization Research Division
Phone:(703)341-7506
FAX (703)341-7575
Regions 6-10
Mr. Phil Arberg
National Exposure Research Laboratory
Characterization Research Division
(702) 798-2545
FAX (702) 798-2692
For information about the Technology Support Center at CRD-LV, contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2270
(702) 798-3146 (Fax)
The Technology Support Center fact sheet series is developed by Clare L. Geriach,
Lockheed Environmental Systems & Technologies Company, Las Vegas.

-------
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TECHNOLOGY SUPPORT
»EPA
INTRODUCTION
TECHNIQUE
THEMATIC MAP
PRODUCTS
MENSURATION
PRODUCTS
Photogrammetry
for Environmental
Measurement
The Characterization Re-
search. Division in Las Vegas
(CRD-LV) has an active
remote sensing department,
capable of responding to all
Regional requests for obtain-
ing and interpreting aerial
photography. Photogramme-
try is defined as the "art and
science of obtaining reliable
measurements from photo-
graphs" (American Society
for Photogrammetry and
Remote Sensing, 1991).
Most small and medium scale
maps are made from aerial
photographs, and photogram-
metric sciences are a funda-
mental part of modem map
making. The aerial photo-
graphic holdings in the EPA
and other agencies of the
federal government are a
wealth of spatial and tempo-
ral data about environmental
conditions and processes.
CRD-LV currently provides
qualitative information that is
interpreted from aerial photo-
graphs to characterize hazard-
ous waste sites, analyze
wetlands, identify ecological
resources and to meet a
number of environmental
monitoring needs. CRD-LV
has now acquired the capabil-
ity to supply highly accurate
measurement information for
similar applications.
Photogrammetric data are
produced on very precise
photo-measurement devices
called analytical
stereoplottere. These
devices, typically calibrated
to the micron level, enable
the scientist to create com-
plex mathematical models
that correct for known
distortions in the photo-
graphs. From these three-
dimensional photo models,
highly accurate measure-
ments and positional data
can be derived for mapping
and analytical purposes.
These data can be produced
in digital format directly for
input in a Geographic Infor-
mation System (GIS).
Cartographic information can
be produced from aerial
photographs to meet National
Map Accuracy Standards.
The information can be
traditional map features such
as roads and hydrology or
special map layers such as
historical hazardous waste
site activity and fractures in
the bedrock. Any information
that can be derived from the
aerial photo can be accu-
rately mapped in a digital
format. Once the photo
model is established, the-
matic information repre-
sented by points, lines, and
polygons can be input directly
in digital format without
transfer to a hard-copy map
and digitizing from the map
base. This saves time and
reduces errors.
Exact measurements can be
accomplished on an analyti-
cal stereopiotter to help
characterize activity of
environmental interest. For
example, in studying hazard-
ous waste sites, the volume
of waste accumulation and
changes In this volume-era
needed to evaluate remedial
options. Also, precise
distance and area measure-
ments can be utilized for risk
assessment and other site
characterization activities.

-------
PRECISE LOCATION
OF FEATURES
ADVANTAGES
FUTURE PLANS
reject A.
MOGY
Any feature that is observ-
able on an aerial photograph
can be accurately referenced
to a coordinate system.
Photogrammetry can be
extremely useful for collecting
and recording the coordinate
data that are required by the
EPA Locational Data Policy.
Information that is not readily
visible on photographs, such
as property boundaries or
pipelines locations, can be
superimposed digitally onto
the photo model for special
mapping or interpretive
purposes.
Cartographic information that
depicts the elevation of the
land surface, such as the
contour map or the digital
elevation model, can be
produced by photogrammet-
ric techniques. The resolu-
tion of this data can be
tailored to the specific needs
of the project.
^ I echnology *£.
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Photogrammetric products
generated from current and
historical photos have the
same advantages and data
that are interpreted from air
photos: they form a perma-
nent record of present and
past conditions, they are
defensible in court, and they
serve as valuable aids to site-
specific field work. The
ability to provide quantitative
measurements as a supple-
ment to qualitative
photointerpretation products
will significantly enhance
the products and services
available to the EPA
community.
More of the basic photogram-
metry and photointerpretation
products will become avail-
able in digital, GIS formats.
Also, the use of digital
imagery in the photogram-
metric process is currently
being researched and will be
incorporated into future
products as will the use of
digital photography in the GlS
environment.
REFERENCE
American Society of Photogrammetry, Manual of Photogrammetry, 4th Edition, Chester C.
Slama, Editor-in-Chief, American Society of Photogrammetry, Falls Church, VA. 1980.
FOR FURTHER INFORMATION
For further information on photogrammetry, contact the Environmental Photographic Interpre-
tation Center at:
Regions 1-5
Mr. Gordon Howard
National Exposure Research Laboratory
Characterization Research Division
(703) 341-7506
FAX (703) 341-7575
Regions 6-10
Mr. Phil Arberg
National Exposure Research Laboratory
Characterization Research Division
(702) 798-2545
FAX (702) 798-2692
For information about the Technology Support Center at CRD-LV, contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2270
(702) 798-3146 (Fax)
The Technology Support Center fact sheet series is developed and written by
Clare L. Gerlach, Lockheed Environmental Systems & Technologies Company, Las Vegas.

-------
&EPA
INTRODUCTION
THE EPA
LOCATIONAL DATA
POLICY
THE SCIENCE OF
SATELLITE
POSITIONING
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
December 1991
(Revised 1995)
TECHNOLOGY SUPPORT
Global Positioning
System (GPS)
Technology
Global positioning system
(GPS) technology is a
satellite-based radio position-
ing and time-transfer system
that can provide accurate,
three-dimensional geographic
positioning anywhere on the
earth's surface. Developed
by the Department of De-
fense, this technology was
designed primarily for military
navigational systems, but
there are numerous
geocoding applications in the
field of environmental sci-
ence. GPS is an emerging
technology in geodesy,
geography, surveying, and
environmental monitoring and
analysis.
Data collection in environ-
mental monitoring is affected
by spatial considerations.
With the Agency's wide-
spread use of geographic
information systems (GIS) for
environmental analyses, the
quality of the geographic
reference of database items
becomes central to the quality
of the overall scientific
analyses.
In May 1990, after Agency-
wide review, the EPA adopted
the Locational Data Policy
(LDP) with the purpose of en-
suring the collection of accu-
rate, fully documented latitude/
longitude coordinates as part of
all Agency-sponsored data
collection activities. The EPA
accuracy goal has been estab-
lished at 25 meters and the
best collection method is cur-
rently considered to be GPS
(EPA 1991).
By using radio signals from a
constellation of earth-orbiting
satellites, earth-based
receivers can compute highly
accurate three-dimensional
geographic coordinate
positions. Terrestrial posi-
tions can be determined
using different instruments.
GPS utilizes satellite tracking
and ranging to determine a
point's three-dimensional
geocentric coordinates.
If data on the satellite geom-
etry, position, and movement
(called ephemeral data) are
known, the distance to an
earth-based receiver can be
geometrically calculated by
measuring the time it takes
for the radio signal to reach
the receiver. This type of
positioning is only possible
because of the accuracy and
speed of modern clocks and
computers. Ephemeral data
are constantly monitored by a
network of earth tracking
stations and relayed back to
the satellite where they are
included in the transmitting
signal and tracked by the GPS
receiver. If this ranging
process is repeated constantly
from several satellites, and
known errors caused by clock
timing and atmospheric effects
are modeled, a precise posi-
tion can be calculated and
referenced to a known datum
and coordinate system (Wells
etal., 1986).
HOW ACCURATE IS
IT?
Accuracy depends on several
factors including the design
of the receiver. There are
two general classes of GPS
receivers: navigation and
geodetic. By employing two
or more GPS receivers with
another that is located over a
known geodetic control point,
navigation grade instruments
can routinely yield accuracies
in the 2-5 meter range. The
geodetic quality units can
compute coordinates with
millimeter level accuracy.
1342EX91

-------
APPLICATIONS
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Apart from the traditional
types of geocoding, surveying,
and the collection of accurate
latitude/longitude coordinates,
one of the main applications of
this technology is in the area
of GIS. GPS technology
provides a means of
evaluating and quantifying the
spatial accuracy of digital map
data as well as creating digital
cartographic data structures.
Potential products and
application areas include:
• Direct Digital Mapping -
Portable GPSs can be
hand-carried or mounted on
vehicles to create digital
data structures that can be
used as direct input into GIS
systems. The system is
used to update existing map
data, provide highly accu-
rate subsections, or create
entirely new map products.
Field Navigation - Field
sampling teams can use
GPS to easily and accu-
rately record the location of
specific sampling locations
or to navigate back to a
previous sampling point
even when surface markers
have been disturbed or are
no longer present.
Quality Control - A carefully
planned GPS survey can
provide first order control
locations which can then be
utilized to assess the
spatial quality of other
thematic overlays that have
been developed for the
database or to geo-
reference raw data layers,
such as satellite or aerial
images.
1 Network Modeling - Kine-
matic (mobile) positioning
techniques can be used to
create network structures
with much greater accu-
racy and precision than is
currently possible. Spatial
variations in movement
and rate, and time series
analysis can be acquired
at greater data resolutions.
Photogrammetric Control -
Photogrammetry and
cartography often remain
the most cost-effective
methods of creating
thematic maps. The ease
of establishing a control
configuration for existing
aerial photographs with
GPS technology as
opposed to traditional
surveying methods can
result in significant saving!
in cost, time, and man-
power.
REFERENCES
Wells, D. E., N. Beck, D. Delikaraoglou, A. Kleusberg, E. J. Krakiwsky, G. Lachapelle, R. B.
Langley, M. Nakiboglu, K. P. Schwarz, J. M. Tranquilla, and P. Vanicek, Guide to GPS Posi-
tioning. Canadian GPS Associates, Fredericton, N.B., Canada, 1986.
U.S. Environmental Protection Agency, Locational Data Policy Implementation Guidance -
Draft. Office of Information Resources Management, Washington, D.C. 20460,1991.
FOR FURTHER INFORMATION
For further information about GPS systems or applications to a specific environmental
application, contact Terrence Slonecker or Mason Hewitt.
Terrence Slonecker
National Exposure Research Laboratory
Characterization Research Division
166 Bicher Road
Vint Hill Farms Station
Warrenton, Virginia 22186
(703)341-7511
Mason Hewitt
National Exposure Research Laboratory
Characterization Research jBwision
P.O. Box 93478
944 East Harmon Avenue
Las Vegas, Nevada 89193
(702) 798-2377
For information about the Technology Support Center at CRD'LV, contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702)798-2270
(702) 798-3146 (Pax)

-------
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
September 1992
(Revised 1995)
?/EPA
INTRODUCTION
DATA SOURCES
acquisition AND
archiving
Historical Maps
and Archiving for
Environmental
Documentation
The location, extent and
history of activities at hazard-
ous waste sites is of great
interest to the U.S. Environ-
mental Protection Agency
and can be documented
through the analysis of
historical records such as
aerial imagery, historical and
thematic maps and other
cartographic data. Since its
inception, the Characteriza-
tion Research Division in Las
Vegas (CRD-LV) and
Warrenton, Virginia field
station has been collecting
and anal^ing these data
sources for environmental
site analyses and civil and
criminal actions. Cases are
brought by the Department of
Justice, FBI, and National
Enforcement Investigations
Center. Prosecutions related
to CERCLA, RCRA, National
Environmental Policy Act,
and Clean Water Act viola-
tions serve as support for
EPA Regional offices' investi-
gations at hazardous waste
sites across the country.
Aerial imagery is the corner-
stone data source used by
CRD-LV during the comple-
tion of environmental site
analysis. Historical aerial
photography records the
evidence of past commercial
or industrial activities as well
as changes in topography,
hydrology and vegetation
brought about by industrial
development. Aerial photo-
graphic coverage dating back
to the late 1920s is available
for portions of the industrial-
ized U.S. Other types of
aerial imagery used at CRD-
LV include color infrared
photographs (useful in
detecting vegetation stress)
and thermal infrared imagery
which records qualitative
variations in surface tempera-
tures and can be used to
identify leachate discharge
points, past disposal activi-
ties, and subsurface pipe-
lines. Historical maps date
back to the mid 1850s and
consist of U.S. General Land
Office land surveys, U.S.
Army Corps of Engineers river
and harbor charts, fire insur-
ance maps and early U.S.
Geological Survey topo-
graphic maps (late 1880s).
Thematic maps such as soil
surveys and bedrock or
surficial geology maps date
back to the turn of the century
and can provide information
on the subsurface environ-
ment which may in turn
measure the migration of
contaminants in ground water.
Historical aerial photographs
are available from federal
agencies (such as USDA,
USGS, NOAA, and USEPA),
state agencies, and private
vendors responsible for their
production. Archival aerial
photographs from some
federal agencies are stored
at the National Archives in
Washington, D.C. Aerial
photographs acquired from
the above sources are
indexed and added to CRD-
LV's film archive, which
currently includes over
150,000 frames of imagery.
When current photography is
required, CRD-LV Initiates an
overflight of the site being
studied. These overflight
photographs are indexed in
the CRD-LV film archive.
Historical maps are available
through a number of sources
such as the National Ar-
chives, Library of Congress,
state libraries, university
libraries, and state and
county offices. Thematic
mapslfe available from the
agency responsible for their
production, e.g., USDA SCS
Soil Surveys, USGS Geologic
Quadrangle Maps. These
maps are acquired and
cataloged as collateral data
and remain with the CRD-LV
library-filed project folder.
Historical land use data
including census tracts are
avaM at the MsBonal
Archives, as well as state or
university libraries, and can
be acquired to support land-
use mapping.
1307EX82OOC

-------
APPLICATIONS
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Apart from the traditional
types of geocoding, surveying,
and the collection of accurate
latitude/longitude coordinates,
one of the main applications of
this technology is in the area
ofGIS. GPS technology
provides a means of
evaluating and quantifying the
spatial accuracy of digital map
data as well as creating digital
cartographic data structures.
Potential products and
application areas include:
• Direct Digital Mapping -
Portable GPSs can be
hand-carried or mounted on
vehicles to create digital
data structures that can be
used as direct input into GIS
systems. The system is
used to update existing map
data, provide highly accu-
rate subsections, or create
entirely new map products.
Field Navigation - Field
sampling teams can use
GPS to easily and accu-
rately record the location of
specific sampling locations
or to navigate back to a
previous sampling point
even when surface markers
have been disturbed or are
no longer present.
Quality Control - A carefully
planned GPS survey pan
provide first order control
locations which can then be
utilized to assess the
spatial quality of other
thematic overlays that have
been developed for the
database or to geo-
reference raw data layers,
such as satellite or aerial
images.
• Network Modeling - Kine-
matic (mobile) positioning
techniques can be used tc
create network structures
with much greater accu-
racy and precision than is
currently possible. Spatial
variations in movement
and rate, and time series
analysis can be acquired
at greater data resolutions
Photogrammetric Control
Photogrammetry and
cartography often remain
the most cost-effective
methods of creating
thematic maps. The ease
of establishing a control
configuration for existing
aerial photographs with
GPS technology as
opposed to traditional
surveying methods can
result in significant savin!
in cost, time, and man-
power.
REFERENCES
Wells, D. E., N. Beck, D. Delikaraoglou, A. Kleusberg, E. J. Krakiwsky, G. Lachapelle, R. B.
Langley, M. Nakiboglu, K. P. Schwarz, J. M. Tranquilla, and P. Vanicek, Guide to GPS Posi
tioning. Canadian GPS Associates, Fredericton, N.B., Canada, 1986.
U.S. Environmental Protection Agency, Locational Data Policy Implementation Guidance -
Draft. Office of Information Resources Management, Washington, D.C. 20460,1991.
FOR FURTHER INFORMATION
For further Information about GPS systems or applications to a specific environmental
application, contact Terrence Slonecker or Mason Hewitt.
Terrence Slonecker
National Exposure Research Laboratory
Characterization Research Division
166 Bicher Road
Vint Hill Farms Station
Warrenton, Virginia 22186
(703)341-7511
Mason Hewitt
National Exposure Research Laboratory
Charaeterizltion Research Division
P.OTBox 93478
944 East Harmon Avenue
Las Vegas, Nevada 89193
(702) 798-2377
For information about the Technology Support Center at CRD-LV, contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 80193-3478
(702) 798-2270
(702) 798-3146 (Fax)
The Technology Support Center fact sheet series is developed by Clare L Gerlach,
Lockheed Environmental Systems & Technologies Company, Las Vegas.

-------
SEPA
INTRODUCTION
instrumentation
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
November 1990
(Revised 1995)
TECHNOLOGY SUPPORT
Field Screening
Methods for
Radioactive
Contamination
vA/WWV1
The complexity of hazardous
waste sites presents a
challenge to field scientists
and decision makers in the
remediation process. There
is growing concern in the
technical and secular com-
munities about the likelihood
of radioactive contaminants
at sites previously thought to
contain only organic or
inorganic material. Hazard-
ous waste site problems can
be described broadly as:
• Low level without radioac-
tive contamination
•	High level without radioac-
tive contamination
•	Low level with low level
radioactive contamination
•	Low level with high level
radioactive contamination
•	High level with low level
radioactive contamination
•	Radioactive contamination
only
•	High level with high level
radioactive contamination
Surveys are recommended
for sites that are suspected of
containing radioactive waste.
This cautionary measure can
identify problems early in the
site characterization proce-
dure and can isolate areas
that require special care in
the remediation program.
Portable instruments are
available that will determine
the presence of radioactive
hot spots in a quick, semi-
quantitative manner. These
instruments are not isotope
specific, but do identify the
source as an alpha, beta, or
gamma ray emitter.
Several portable instruments
are commercially available
that can detect alpha, beta,
and gamma radiation. The
alpha counter is a separate
unit from the beta/gamma
counter. Each is battery
operated, smaller than a
shoebox, and easily man-
aged by one fold scientist.
The beta/gamma counter
operates in two modes: with
the shield closed, it detects
gamma rays; with the shield
open, it detects beta plus
gamma rays. The amount of
beta radiation ean be deter-
mined by the subtraction of
gamma from beta plus
gamma. Tte readings a®
displayed on an analog meter
in miWreffWhour or counts/
minute.
Another device that is
amenable to field survey use
is the portable ion chamber*
It is a hand-held instrument
with charged gas in a cham-
ber and is useful for the
detection of gamma radiation.
A "pancake" detector is often
used for quick screening of
dothirfa and tat surfaces. It
is sensitive to beta and
gamma radiation and gets its
name from its flat round
shape.
14140(90

-------
FIELD USE
ADVANTAGES AND
LIMITATIONS
FUTURE WORK
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Portable radiation survey
instruments are calibrated
with laboratoiy sources
placed at various distances
from the detectors before the
site survey. A sampling grid
is established following data
quality objective goals. Once
the instruments are ready
and all health and safety
precautions have been
addressed by the field team,
the survey can begin. A
typical approach may consist
of two field personnel, one
with an alpha counter and the
other with a beta/gamma
(also known as Geiger)
counter. Each sampler would
have a log book in which to
record the readings at the
pre-ordafned locations on the
grid. Due to the character of
gamma radiation, gamma
signals will be detected and
counted. It is important that
the sampler hold the counter1
just above the ground surfac
consistently through the
study. For screening pur-
poses, it is essential that any
radiation greater than back-
ground level be investigated j
further to assure a thorough
knowledge of the radioactive
character of the site.
Commercially available
detectors are. generally
reliable, consistent and easy
to use. The strong advan-
tage of knowing the radioac-
tive character of a hazardous
waste site is obvious. It
allows future characterization
and remediation to be
performed intelligently and
safely.
When combined with a
carefully planned laboratory
confirmation, field screening
can be a quick and effective
method for assessing the
extent and location of radio-
active contamination. Liquid
scintillation methods, alpha/
beta counting, alpha spec-
troscopy, and high resolution
gamma spectroscopic
methods can identify the
isotopes and better quantify
the radioactivity at the site.
Advantages
Limitations
•	Rapid, real-time results
•	Low cost (compared with
full laboratory analysis)
•	Easy to use
Inability to probe beneath
surface
Doesn't reveal specific
isotope identity
Difficulty detecting tritium
A low-energy photon detector
system (LEPS) is being
investigated for use at mixed-
waste sites. Using germa-
nium diodes with a high
sensitivity to gamma-and x-
ray energies, this detector
can be encased in a water-
tight container ancjlused
above ground or lowered into
a drilled borehole. This
technology promises remote
sensing of radiation by the
employment of rugged,
submersible detectors.
REFERENCES
Field Monitoring Standard Operating Procedures, U.S. EPA Field Monitoring Branch, #003
EMSL-ORS, 88 pp. 1990.
Moe, H. J., and E. J. Vallario, Operational Health Physics (particularly Chs. 10-12), ANL
publication #88-26,930 pp. 1988.
FOR FURTHER INFORMATION
For further details on field screening meth- For general Technology Support information
ods for radioactive contamination, contact: contact:
Mr. Stephen Pia
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2102
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2270
(702) 798-3146 (Fax)
The
Clare
Technology Support Center fact sheet series is developed and written by
e L. Geriach, Lockheed Environmental Systems & Technologies Company,
Las Vegas.

-------
United States
Environmental
Protection Agency
umce or nesearcn ana
Development
Washington, DC 20460
June
(Revised 1995)
TECHNOLOGY SUPPORT
&EPA
Internal
Dosimetry for
Radionuclides
in Humans
INTRODUCTION
THE FACILITY AND
equipment
Monitoring human exposure
to radionuclides is an integral
component of EPA's mission
to protect the health of the
public. State-of-the-science
equipment and a rigorous
quality assurance program
provide scientists with
accurate information.
Whole body counting is an
internal dosimetry method
that uses gamma spectrom-
etry to identify radionuclides
and to measure their concen-
tration and distribution in a
human body.
Lung counting detects
inhaled radionuclides which
are deposited in the lungs.
Counting of areas of the body
such as the skull, the liver, or
other organs where specific
radionuclides may concen-
trate provides additional
information necessary to
calculate internal radiation
dose. The germanium
detectors used in both the
whole body and lung counter
are passive devices, i.e., they
detect emitted radiation but
Two counting vaults, shielded
with 6-inch thick, pre-World
War II steel walls, provide a
low background area for
counting. One vault, used for
whole body counting, is
equipped with a high purity
germanium detector posi-
tioned over an adjustable
chair in which the subject
reclines during the count.
High energy gamma-emitting
radionuclides, with energies
ranging from 60 keV to
2.0 MeV (such as cesium and
cobalt) can be identified and
measured with this system.
The second vault contains an
adjustable chair with six
state-of-the-art, high-purity
germanium semi-planar
detectors mounted above it.
These detectors, fitted with
very thin "windows" to admit
very low energy radiations,
are designed for detection of
low energy gamma and X-ray
emitting radionuclides (such
as americium and plutonium).
Detected energies range
from 10 to 300 keV. Lung,
liver, skull, and other specific
organ or bone counting is
done here.
Both Qounting vaults have
anticlaustrophobial mea-
sures. One wall of each vault
is covered with a mural to
provide a less institutional
do not emit any radiation
themselves.
Bioassay for tritium, stron-
tium, and other radionuclides
which are not detectable with
gamma spectroscopy is
performed, when necessary.
The Office of Radiation and
Indoor Air (ORIA-LV) in Las
Vegas maintains a whole
body counting facility.
feeling, and the subject may
watch TV or read.
Data acquisition and process-
ing equipment includes a
gamma spectroscopy system
which detects the radiation,
amplifies and shapes the
detector signals, stores and
displays data, ami analyzes
the data to identify radionu-
clides. A fulfy-integrated
a m mim M t 	tum .11! rafcm lit! Mkal
COmpUIOTmiuuiC^
analyzer system Is used, and
the software, including data
acquisition ami analysis, data
base management, word
processing, and statistical
analysis, is tailored for whole
body counting needs.
0388EX91

-------
QUALITY
ASSURANCE
The efficiency of the detec-
tion system is determined by
comparing the amount of
radiation measured by the
counting system to the known
amount in a sample - in this
case, a polyethylene bottle
"phantom" called the
"BOMAB." Its shape and
volume is equal to a "stan-
dard man." Lung and thyroid
phantoms are also used for
efficiency calibration.
An energy calibration is done
daily to correct for the
inherent drift properties of
detectors.
Calibration results are
tracked with a quality assur-
ance software package.
Daily and monthly quality
assurance reports and plots
are generated. Internal and
external audits are routinely
conducted, and permanent
records are kept of quality
assurance and personnel
counting data. This facility
participates in intercalibratior
studies with other whole bod1
counting facilities in the
United States to check on
both efficiency and energy
calibration status.
COUNTING
PROGRAM
SUMMARY
No*'°/V
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Civilian government, Depart-
ment of Defense, commercial
power plant, fuel fabrication
plant, and contractor person-
nel who have a potential for
exposure to radionuclides are
counted routinely. Any
person who feels they may
have been exposed to
radionuclides may make an
appointment for a count.
A program to assess levels of
radionuclides in members of
some of the families residing
in communities and ranches
surrounding the Nevada Test
Site was initiated in Decem-
ber 1970. The Community
Monitoring Station Network, a
joint endeavor among
Department of Energy,
Environmental Protection
Agency, and the Desert
Research Institute of the
University of Nevada, was
established in 1981. The
station managers of this
network, who are generally
science teachers in their
communities, and their
families, entered the countini
program at this time. The
families who participate in
this program are located in
Nevada, California, and Utal
The internal dosimetry
program and the networks
maintained by ORIA-LV
around the Nevada Test Site
and in the states west of the
Mississippi River provide for
the monitoring erf human
exposure to radionuclides.
Whole body counting is
provided free of charge, by
appointment only, to EPA
Regional personnel and their
contractors who are involve*
with radioactive or mixed
waste cleanup programs am
other work involving expo-
sure to radionuclides.
FOR FURTHER INFORMATION
For further information on whole body counting,
contact:
Mr. Robert E. Mosley
U.S. Environmental Protection Agency
Office of Radiation and Indoor Air
P.O. BOX 93478
Las Vegas, NV 89193-3478
(702) 798-2597
For Technology Support Center information
contact:
Mr. Ken Brown, Director
Technology Support Center
UA-Erivironmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702)798-2270
(702) 798-3148 (Fax)
* Sloped and wHUm by
Ciare L. Gerlach, Lockheed Environmental Systems & Technologies Company,
Las Vegas.

-------
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
November 1994
(Revised 1995)
TECHNOLOGY SUPPORT
Ambient
Gamma
Radiation
Monitoring
JWWW
Environmental radiation can be
analyzed from two perspectives:
impact on environmental sys-
tems and impact on biological
systems. Dose measurement is
the analysis of the amount of
energy deposited in matter or
tissue and its damaging effect
(usually on humans). Exposure -
measurement is the measure-
ment of environmental radiation,
especially X-rays and gamma
rays, below 3 MeV in air.
The Office of Radiation and
Indoor Air (ORIA-LV) is a
national authority on the moni-
toring of environmental radia-
tion. This analytical expertise
includes the measurement of
ambient gamma radiation, tri-
tium, and nobie gases.
The measurement of expo-
sure rate is currently done by
pressurized ion chamber
(PIC) technology. Six
field-portable PICs are cur-
rently available through the
ORIA-LV. They can provide
real-time monitoring for any
releases of radiological mate-
rial. Instruments at the
ORIA-LV were able to detect
radioactivity from the
Chernobyl accident in 1988.
These instruments are so
sensitive that readings vary
with altitude (cosmic radia-
tion) and with radioactivity in
the soil (terrestrial radiation).
Integrated ambient gamma
exposures over extended
periods of time are also mea-
sured using thermolunines-
cent dosimeter (TLD) tech-
nology.
The PIC is a spherical shell
filled with argon gas to a pres-
sure of 25 atmospheres, in the
center of the chamber is a
spherical electrode with a
charge that is opposite to the
outer shell. When gamma radi-
ation penetrates the sphere, ion-
ization of the gas occurs and the
ions are collected by the center
electrode. The electrical current
generated is directly proportion-
al to the amount of energy de-
posited in the chamber, and
thus to the ambient gamma radi-
ation exposure level at the mon-
itoring location.
The PIC network continuously
measures ambient gamma radi-
ation exposure rates. Because
of its sensitivity, the network
detects low-level exposure rates
and changes that might not be
seen by other monitoring meth-
ods. The primary function of the
PIC network is to detect
changes in ambient gamma
radiation levels. These changes
can be caused by barometric
pressure shifts and from
other meteorological changes
as well as from the presence
of sources of ionizing radia-
tion. The PIC network is
capable of providing near
real-time documentation of
radioactive cloud passage as
might result from an
unplanned release from
nuclear testing operations.
A total of 27 PIC stations
have been established in
communities around the
Nevada Test Site (NTS).
These communities are locat-
ed in Nevada, Utah, and
California. In routine opera-
tion, equipment installed at
each station continuously
measures observed ambient
gamma radiation levels.
Every five minutes the equip-
ment automaticaiiy calculates
and stores the minimum,
maximum, and average
observed ambient gamma
radiation levels fer the previ-
ous five minute period.
Every four hours stored data
is transmitted via satellite
telemetry using the Geosta-
tionary Operational Environ-
mental satellite (GOES)
directly to a receiver earth
station at the NTS and then
to ORIA-LV via a dedicated
telephone line.
Because of the sensitivity of
the equipment, site-specific
limits for "natural back-
ground" have been estab-
lished. If the established
threshold is exceeded for two
consecutive five minute sam-
ples, the system automatical-
ly switches into an "alarm"
mode and transmits data
mm frequently. The loca-
tion, operational states, and
IMlA	— —	•**- - Agia	J
mOSt recently uonMmoCl
data for each station may be
shown on computer graphic
displays in the nuclear test
operations control room at
the NTS and at ORIA-LV.
	(Continued)
0069odc94

-------
Pressurized Ion
Chambers
cont'd.
Thermoluminescent
Dosimetry
Data Interpretation
Applications
^T,°%
All data collected by the PIC are
stored on magnetic tape or solid
state removable recording de-
vices installed at each station.
The stored data is manually
retrieved and processed on a
weekly basis to confirm the accu-
racy of satellite transmissions.
In addition to satellite teleme-
try and on-station magnetic
or solid state recording, data
are recorded on strip charts.
The strip chart recording is
visible at the station location.
Each station also includes a
liquid crystal display. The
combination of strip chart and
liquid crystal display allows
an interested individual to
monitor real-time readings
and readings recorded over
the previous 24 - 48 hours.
Thermoluminescent dosimeters
(TLDs) can be used to measure
environmental gamma radiation
exposures intergrated over
extended periods of time. The
exposure integration period for
environmental applications nor-
mally approximates a calendar
quarter. In this context TLDs
are fundamentally different from
PICs, which can provide near
real-time highly detailed mea-
sures of plume passage.
Environmental TLDs monitor
accumulated, long-term expo-
sure in areas surrounding the
NTS. Each environmental
TLD contains 3 simultane-
ously exposed and identically
filtered CaSO.:Tm phos-
phors. TWo TLDs are
deployed at each monitoring
location, thereby providing up
to 6 replicate data points.
This phosphor-filtration com-
bination provides excellent
sensitivity at the low levels
encountered in environmental
monitoring situations. The
phosphor is not direcly tissue
equivalent, so no attempt is
made to express results in
units descriptive of an
absorbed dose equivalent in
humans. TLDs used to moni-
tor personnel use a combina
tion of phosphors and filtra-
tions. Evaluating the ratios of
the phosphor-filtration
resposes from personnel
TLDs permits an estimation
of the radiation type and
energy to which the dosime-
ter was exposed, thereby
providing a mechanism for
assessing the absorbed dose
equivalent.
The data are evaluated weekly
by ORIA-LV personnel. Trends
and anomalies are identified
and investigated. Equipment
problems are referred to field
personnel for correction. Weekly
PIC averages are compiled from
the periodic telemetry data and
from the 5-minute averages
recorded on the removable stor-
age devices. Computer-gener-
ated reports of the PIC weekly
average data are issued for
posting at each station.
These reports show the
reporting week's average
gamma exposure rate, in
units of microRoentgens per
hour (pR/hr). In addition, the
reports include the average
observed in the previous
week, the average over the
previous year, and the range
(minimum and maximum) of
natural background radiation
levels for the United States.
Results obtained from read-
ing environmental TLDs are
reported in units of
mR/deployment period. The
result reported is the mean
measurement obtained from
3 - 6 simultaneously exposec
and iderrticatly filtered
CaS04:Tm phosphors.
Whenever measurement of low
levels of ambient gamma radia-
tion is of concern, it is appropri-
ate to consider a monitoring pro-
gram that includes using PICs.
Following mobilization of the
response team and placement
of PICs, monitoring ambient
gamma radiation levels in the
environment is a matter of
collecting and evaluating
data. The experts at the
ORIA-LV are ready to-work
with Regional personnel to
assure the appropriate use 0
and to provide experienced
data interpretation for result*
obtained using these sensi
tive technologies.
%
echnology
i? Technok_ ^
8	I (702) 798-2320
J
FOR FURTHER INFORMATION
For more information about pressurized ion
chamber (PIC) or thermoluminescent
dosimeter (TLD) technology, contact:
Mr. Bruce B. Dicey, Senior Health Physicist
U.S. Environmental Protection Agency
Office of Radiation and Indoor Air
P.O. Box 93478
Las Vegas, NV 89193-3478
For information about the Technology Support
Center at CRD-LV, contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. Envl/onmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702)798-2270
(702) 798-3146 (Fax)
The Technology Support Center fact sheet series ialeveloped and written by Clare L
Lockheed Environmental Systems & Technologies Company, Las Vegas.

-------
United States	Office of Research and	November 1991
Environmental	Development	(RevisedS
Protection Agency	Washington, DC 20460	'
SEPA
INTRODUCTION
BACKGROUND
FIELD USE
TECHNOLOGY SUPPORT
Immunochemistry
for Environmental
Monitoring
The Characterization Re-
search Division in Las Vegas
(CRD-LV) is pioneering an
investigation into the useful-
ness of several immunochemi-
cal techniques for monitoring
the extent of contamination in
various environmental and
biological matrices. Immuno-
chemistry includes all methods
of sample preparation and
analysis that incorporate
antibodies that have been
developed for specific analytes
or groups of analytes.
Enzyme-based immuno-
chemical techniques have
been in use since the 70s
and more recent efforts have
focused on their applicability
to the complex matrices that
face environmental scientists.
The CRD-LV has developed
and demonstrated several
immunochemical techniques
and believes that these
methods hold great promise
for the quantitative analysis
of target analytes for use in
ground-water surveillance,
in situ hazardous waste site
monitoring, and assessment
of human exposure. Current
work involves the analysis of
chemicals, like PCBs,
nitroaromatics, and certain
pesticides, that are difficult to
analyze by other analytical
methods.
Immunochemistry includes
techniques such as
immunoaffinityand immuno-
assay. Immunoaffinity is a
sample preparation proce-
dure that takes advantage of
the attraction between an
antibody and a specific
analyte. Immunoaffinity
preparations have great
potential for cleanup of
complex samples like dioxins.
By rinsing a sample over an
antibody-treated surface,
scientists can isolate particu-
lar compounds in the sample
that adhere to the antibody.
The isolated compound is
then elated from the immobi-
lized antibody and is ready
for analysis by chromatogra-
phy or Immunoassay. One
common immunoassay is the
enzyme-linked immuno-
sorbent assay (ELISA). The
specificity of the antibody for
the analyte and the resultant
immune complex is the basis
for the specificity of immuno-
assays. Most field immuno-
assays are colorimetric
analytical methods that
quantify compounds of
interest. A sample is spiked
with a known amount of a
labelled analyte. The label is
typically an enzyme. A
chromogenic substrate is
added to serve as an
indicator of compound
concentration in the sample.
Laboratory-based immuno-
assays include fluorescent
and radioactive methods that
have greater sensitivity but
are less portable.
Immunoassays are portable,
rugged, and inexpensive.
Their use at hazardous waste
sites has been investigated by
the CRD-LV. The results of
Superfund Innovative Tech-
nology Evaluation (SITE)
studies indicate a strong
correlation between field
immunoassays, laboratory
immunoassays, and gas
chromatography/mass
spectrometry. The only
equipment needed is a
spectrophotometer, various
microtiter plates or test tubes,
precision pipets, and immuno-
logic reagents. The 96-well
microtiter plate It approxi-
mately 3" x 6" and has 96
depressions, each capable of
holding about 250 liquid.
Smaller microtiter strips are
available that can be as-
sembled to form modular
sections for individual
analytes. These plates and
test tubes are available pre-
coated with the antibody
by workers who deal with
hazardous chemicals. Dosi-
meter badges with an immu-
nochemical twist are available
for pentachtorophenol and
nftroaromatfct. These
personal exposure monitors
are tightwaight,
inexpensive, can be analyzed
quickly , and provicje real time
Another Ml use of immuno-
chemMiy m bejrw explored
at the CRCWLV. rote use may
revolutionize safety and
exposure precautions used
indication of exposure. These
badges employ a micro-
dialysis tubing eor^tfning an
inwflmWMWii iwHtwJoy pnsHw«
Immediate identificaBon of
high exposure levels is critical
to the conduct of safe site
characterization.
11460(91

-------
ADVANTAGES AND
LIMITATIONS
FUTURE
The use of immunochemical
techniques is gaining accep-
tance in the area of environ-
mental science. One need
that is being addressed is
that of specificity. Fre-
quently, immunoassays are
available for a class, like
PCBs. Specific quantitation
for each component would be
difficult.
PEMs are available for
pentachlorophenol and are
being developed for para-
thion and chlorpyrifos. The
development of PEMs must
address the question of
Advantages
Limitations
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Field portable
User friendly
Quick and inexpensive
Potential for wide range of
analytes
Useful for many matrices
Low detection limits
Separate immunoassay
needed for each analyte I
More complex analysis
required for quantitation of
specific analytes
Long development time
for new antibodies and
methods
diffusion of chemicals
through the dialysis tubing,
the optimum concentration of
the antibody, detection limits
and quantitation of the
badge, the efficiency of the
antibody in capturing the
analyte, and the capacity of
the device.
The CRD-LV is active in the
development of all immuno-
chemical methods that have
potential for Agency use.
One new avenue of investiga-
tion is the use of antibody-
coated fiber optic immuno-
sensors. Another application
is the integration of robotics
capability for high sample
throughput and a tiered
analytical approach, i.e.,
biological and environmental
samples, biomarkers, target
analytes, and degradation
products. This system of
analytical procedures will
enable scientists to measure
contamination at the source,
follow the fate and transport
of residual amounts, and
i human exposure..
Multi-analyte immunoassays
that can identify several
analytes simultaneously are
expected to expand the
desirability of immunoassay
technology for environmenta
use. Work in this area is
already underway at the
CRD-LV.
REFERENCE
Immunochemical Methods for Environmental Analysis, J. M. Van Emon and Mumma, R. O.
eds., ACS Symposium Series 442, ACS, Washington, DC, 229pp. 1990.
FOR FURTHER INFORMATION
For further information about immunq-
chemistry for environmental monitoring,
contact:
Dr. Jeanette Van Emon
Immunochemistry Program
U.S. Environmental Protec-
tion Agency
National Exposure Research
Laboratory
Characterization Research
Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702)798-2154
FAX (702) 798-2243
Forjofoonation about the Technology
Support Center at CRD-LV, contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Chyaotortzation Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2270
(702) 798-3146 (Fax)
The Technology Support Center fact sheet series is developed and written by
Clar0 L Geriach, Lockheed Environmental Systems & Technololges Company, Las Vegas.

-------
uniiea states	umce ot t-tesearcn ana	June 1991
Environmental	Development	(Revised iqq^
Protection Agency	Washington, DC 20460
TECHNOLOGY SUPPORT
&EPA
High Resolution
Mass
Spectrometry
INTRODUCTION
instrumentation
The identification and
quantitation of organic
compounds is a fundamental
goal of both CERCLA and
RCRA. When the identity of
the organic compound is
known, the formal CLP
methods are generally able to
address the quantitation
needs. Often, however, the
exact identity of an organic
contaminant is not obvious
and is intractable to the
commonly used low resolu-
tion mass spectrometer. in
these cases, a little chemical
detective work is neededl
Many thousands of pollutants
exist, but only a few hundred
matching standards are
available, predominantly for
the Target Compound List
(TCL) pollutants. High
resolution mass spectrom-
eters (HRMS) have been
developed to provide a closer
reading of the fingerprint of a
molecule or element. With
HRMS It is possible to isolate
specific characteristic ions,
determine their accurate
mass, and thus assign the
correct elemental composi-
tion without reference stan-
dards. Thus, HRMS is a
valuable tool for structure
determination, and has
largely replaced other
techniques such as elemental
analysis for structure verifica-
tion. Data interpretation is
complex, as is the instrumen-
tation. Expert analysts must
combine their knowledge of
chemical interactions with
super-sleuthing capabilities to
effect a complete and suc-
cessful identification. The
Characterization Research
Division in Las Vegas (CRD-
LV) has the analytical exper-
tise and instrumentation
necessary to provide an-
swers to the most difficult
problems of environmental
analysis.
Mass spectrometry is a three-
phase analytical procedure
consisting of ionization,
separation, and detection.
High resolution mass spec-
trometry differs from other
techniques primarily in the
separation capability. High
resolution instruments are
able to separate tons having
the same nominal mass but
differing in specific elemental
composition and hence in
accurate mass, because
each element varies from
integral mass slightly and
differently (except carbon, set
at 12.0000). HRMS has
been applied to organic and
inorganic identification at
ultratrace levels. For ex-
ample, minor organic con-
taminants, rare earth ele-
ments, and lead isotope
ratios can be identified and
used for site-specific finger-
printing. The high resolution
instrument is much larger and
more expensive than the
commonly used quadrupole
mass spectrometer. It
contains a large magnet and
an electrostatic sector to—
provide £ focused Beam of
ions for determinations of
mass that are accurate to
1/1000 of a mass unit. T.his
ability to separate com-
pounds having the same
integer mass number is a
great advantage to the
analyst who is faced with a
particularly difficult mass
assignment. High resolution
mass:
equipped with special Inlet,
ionization, and computer
systems to maximize their

-------
interpretation
The interpretation of high
resolution mass spectral data
is a complex procedure. A
skillful and experienced
spectroscopist incorporates
several areas of expertise
into a thoughtful reading of
the experimental data. The
analyst uses historical
information about the site and
its contamination, early
results from low resolution
mass spectrometry, knowl-
edge of the probable chemi-
cal reactions, precursors, by-
products, and experience in
recognizing the statistical
significance of a measure-
ment that borders between
two interpretations. Some-
times the particular compo-
nent of interest has been
depleted or altered by
biodegradation,
photodegradation, or anoth^
agent. The mass spectral
analysis must then be
thoughtfully focused upon
chemical precursors or by-
products of the original
compound.
ADVANTAGES AND
LIMITATIONS
The complexity of high
resolution mass spectrometry
interpretation demands
considerable interpretive
expertise. This level of effort
is justified for identification of
unknown toxic contaminants
during site characterization
and remediation. It can also
allow the unambiguous
correlation of off-site contami-
nation to a specific site.
Advantages
Dependable, high sensitiv-
ity detection
Legally defensible
determinations
. Ability to identify previ-
ously unlisted compounds
Site fingerprinting
Limitations
Costly instrumentation
Expert interpretation is
needed
REFERENCES
The Wiley/NBS Registry of Mass Spectral Data, F. W. McLafferty and D. B. Stauffer, eds., 1 qj
Interpretation of Mass Spectra, 3rd Edition, F. W. McLafferty, University Science Books, 19$q
FOR FURTHER INFORMATION
The CRD-LV will support the Regions in the determination of the identity of compounds that
are intractable to routine analysis. This assistance can aid in the identification of the Poten-
tially Responsible Party (PRP).
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For more information about specialized mass
spectrometry sen/ices available at CRD-LV
through the Technology Support Center,
contact:
Dr. Wayne Sovocool
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702)798-2212
For information about the Technology Suppc
Center at CRD-LV, contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2270
(702) 798-3146 (Fax)
The Technology Support Center fact sheet series is developed and written by
Clare L Gerlach, Lockheed Environmental Systems & Technologies Company,
Las Vegas.

-------

INTRODUCTION
instrumentation
SCOPE
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
August 1990
(Revised 1995)
TECHNOLOGY SUPPORT
Open Path FT-IR Use in
Environmental Monitoring
A major environmental
concern is the identification,
location, and extent of volatile
organic compound (VOC)
contamination in the air at
hazardous waste sites. Open
path (or long path) FT-IR was
adapted to environmental use
to address the need for
information about VOC levels
and to improve upon costlier
and more time-consuming
current methods. Open path
FT-IR is useful at many
stages of screening and
remediation because VOC
contamination can result from
many sources, including
underground storage tank
leaks, chemical spills, and off-
gassing at air stripping plants.
A mobile system has been
developed at Kansas State
University through a coopera-
tive agreement with CRD-LV
and Region 7. The mobile
laboratory set-up provides an
on-site, quick turnaround
means of obtaining data that
can guide remediation deci-
sions. The outlook for ex-
panded use of open path
FT-IR is excellent, with re-
search in the area responding
to the needs of field scientists
and Agency personnel.
The FT-IR spectrometer
being used for developmental
work is a Bomem DA02
system equipped with a KBr/
Ge beam splitter, a mercury-
cadmium-telluride detector
that is liquid nitrogen cooled,
an adjustable tripod, and a
collection telescope (10-inch
Cassegrainian). The source
is an air cooled and quartz
shielded Nemst glower
operating at 2,000 Kelvin.
This source is located at the
focal point of a 20-inch
Newtonian telescope in order
to generate a collimated
beam of infrared radiation.
The mobile laboratory is
driven to one side of the site
to be surveyed and the FT-IR
spectrometer with its collec-
tion telescope is set up
adjacent to the station. The
IR source and its collimating
telescope are positioned on
the opposite side of the site
to be surveyed so that the
collimated beam of infrared
radiation may be sent across
to the collection telescope of
the FT-IR spectrometer. A
laboratory calibration Is
usually sufficient for field
sampling.
An alternative arrangement is
to place both the source and
the spectrometer adjacent to
the laboratory station. Then a
reflector is placed on the
opposite side of the site so
the collimated beam of
infrared radiation is sent
across the site to the reflector
and bounced back to the
spectrometer. In either
arrangement, the IR absorp-
tion spectrum of the atmo-
sphere above the site is used
to identify any VOC present in
the path of the beam.
Open path FT-IR is useful for
the qualitative and quantita-
tive measurement of VOC
and low-boiling semivolatile
compounds. To date, the
spectral database contains
35 VOC files, with a total of
70 compounds expected to
be included by the end of
1990. The instruments can
be positioned at varying
heights above the soil by
using tripods. Though this
technology is sensitive to-
meteorological factors such
as wind, particulate matter,
and rain, most of these
affect point sampling by
canister as well. Open path
FT-IR is faster and cheaper
than the canister methods
while providing a greater
likelihood of locating the
pollutant plume and should be
the favored technique when
time and budgetary con-
straints are considerations.
1323EX90

-------
ADVANTAGES AND
LIMITATIONS
Using open path FT-IR to
analyze the atmospheric
concentration of VOC and
solvents is a newly developed
and emerging technology. It
has many advantages and
some limitations that are
presented here as an aid to
methodology decision-making.
It is obvious that the Data
Quality Objectives (DQO) of a
site must drive the decisions
Advantages
Low analysis cost
Computerized operation
Rapid results
Limitations
In development stage
Equipment is customized
Sensitive to meteorological changes
on instrumentation so that the
necessary data are not
compromised. As with any
new method, specialized
equipment and expert advice
is fundamental to the site-
specific applicability of the
technique.
FUTURE PLANS
As open path FT-IR gains
stature as an environmental
screening tool, work will be
underway to refine its capa-
bilities in quantitation. A
growing database that will
include more VOC and some
semivolatile compounds will
increase the usefulness of
this method. The anticipated
demand for instrumentation
will result in the development
of more sensitive, integrated
systems. Better computer-
ized formats may enable
extrapolation from atmo-
spheric to subsurface con-
centration. The first two
limitations listed above are
not intrinsic to the method
and will be solved with the
advent of commercially
available systems. In gene«
the outlook is very positive |
increased need for screeniri
technologies such as FT-|f^|
and the demand is expect©*
to guide researchers to
promising refinements of
these techniques.
REFERENCES
Fateley, W. G., R. M. Hammaker, D. F. Gurka, Field Demonstration for Mobile FT-IR for
Detection of Volatile Organic Chemicals, EPA Report 600/4-90/008, March 1990.
Spartz, M. L., M. R. Witkowski, J. H. Fateley, J. M. Jarvis, J. S. White, J. V. Paukstelis,
R. M. Hammaker, W. G. Fateley, R. E. Carter, M. Thomas, D. D. Lane, G. A. Marotz,
B. J. Fairless, T. Holloway, J. L. Hudson, and D. F. Gurka, Evaluation of a Mobile FT-IR
System for Rapid VOC Determination, Part 1: Preliminary Qualitative and Quantitative Calibn
tion Results, Am. Envir. Laboratory, November 1989, pp 15-30.
FOR FURTHER INFORMATION
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For further information about Open Path FT-IR, contact:
Dr. Don Gurka
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2312
For information about the Technotogy Support Center, contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2270
(702) 798-3146 (Fax)
The Technology Support Center fact sh&t series is developed and written by
Clare L. Gerlach, Lockheed Environmental Systems & Technologies Company, Las Vegas.

-------
SEPA
urmea orates
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
July 1991
(Revised 1995)
Continuous
Monitoring with
Purge-and-Trap
Gas
Chromatography
INTRODUCTION
Preliminary site assessment
and monitoring of remedia-
tion efforts rely upon timely
and accurate information.
Various methods exist for the
continuous monitoring of
water and air samples. Their
value lies in the elimination of
labor-intensive sample
collection, handling, and
analytical procedures. The
generation of real-time data
permits treatment systems to
operate in a true process
control mode. Additionally,
data quality may be better
since samples are never
subjected to the packaging
and transport needed for
conventional laboratory
analysis.
The Characterization Re-
search Division in Las Vegas
(CRD-LV) is interested in the
application of continuous
monitoring technologies that
will reduce the time-in-field
for environmental scientists
working at Superfund and
RCRA sites.
A system developed by
Analytic and Remedial
Technology, Irta was evalu-
ated for the on-line monitoring
of volatile organic compounds
(VOCs) in a ground-water
treatment process. This
monitoring system, Automated
Volatile Organic Analytical
System (AVOAS), consists of
a sampling manifold, a purge-
and-trap unit coupled to a gas
chromatograph (GC)
equipped with an electrolytic
conductivity (or Halt) detector
and a computer system. The
innovative components of this
system are:
(1) the sampling manifold,
which allows for direct,
on-line intake of samples
from different collection
points or treatment
streams.
(2)	the injector, which allows
direct injection of the
sample into the GC
without the handling and
preparation steps often
associated with VOC loss
due to volatilization.
(3)	the computer software
that is customized for the
analysis system.
The AVOAS was tested at a
Superfund site in Region 1
under the Superfund Innova-
tive Technology Evaluation
(SITE) program. Under the
conditions of this study, the
CRD-LV found this system to
be reliable and easy to use.
Comparisons of data from the
AVOAS study with standard
analytical laboratory results
from sample splits indicate a
strong correlation. The
AVOAS results were consis-
tently higher, pertiaps re-
flecting differences due to
sample loss during transport.
DEMONSTRATION
The evaluation was con-
ducted at the Wells G&H Site
inWoburn, MA, U.S. EPA
Region 1. Ground water at
the site is known to be
contaminated with VOCs.
Remedial action required
treatment of the ground water
to remove the VOC contami-
nation. As a result, a pilot-
scale operation of a ground-
water extraction and treat-
ment system was conducted
to evaluate the relative merits
of three treatment processes;
an ultraviolet/chemical
oxidation process, a carbon
adsorption process, and an
experimental dehalogenation
process.
Six sampling points ki the
treatment train were selected
to monitor the efficiency of
the individual methods for
reducing VOC content.
These discrete samples were
sent off-site for standard
analyses using a purge and
trap GOMS method. This
(Continued)
0697EX91

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DEMONSTRATION
(CONTINUED)
ADVANTAGES AND
LIMITATIONS
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treatment study presented an
excellent opportunity to
demonstrate and evaluate
the AVOAS as an application
of the principles of process
analytical chemistry during a
remediation activity. The
AVOAS was programmed to
collect and analyze samples
at six collection points. In
addition to the GC/MS
samples, matching samples
were taken and shipped to
the CRD-LV for analysis by
EPA GC Method 502.2. The
AVOAS GC analysis is
similar to Method 502.2, j
making direct comparison
allowable. A variety of Qfyd
samples were also analyzed
under each protocol, cons)s. |
tent with the requirements Qf j
the study design.
The use of continuous
monitoring devices holds
great promise for enhancing
the characterization and
remediation activities at a
hazardous waste site. The
increasing number of these
devices coming into the
environmental market puts a
burden of evaluation upon
both manufacturer and
consumer. There is no gain
in sacrificing data reliability
for ease of use. The CRD-LV
will continue to evaluate the
performance of demonstrated
technologies, like the
AVOAS, for applications
where a need is indicated.
Advantages
Limitations
Eliminates problems
associated with
standard VOC
sampling and
transport
Allows selection of
sampling point,
frequency, intervals
Reduces labor costs
Provides real-time,
in-situ data
Minimizes exposure
of field personnel
Initial hardware cost
Problems associated
with long-term operation,
need to be identified
Availability of equipment
Application to other
situations must be
explored
REFERENCES j
Volatile Organic Compounds in Water by Purge and Trap Capillary Column Gas ChromatonrJ
phy with Photoionization and Electrdlyttc Conductivity Detectors in Series, Method 502 2 U c
EPA, Cincinnati, 1986. ' '
Methods for the Determination of Organic Compounds in Water, U.S. EPA, Office of Research
and Development, Cincinnati, 1986.
FOR FURTHER INFORMATION
For more information about this study and
how continuous monitoring of ground water
may help you, contact:
Dr. Stephen Billets
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Us Vegas, NV 89193-3478
(702) 798-2232
r
For information about the Technology Support
Center at CRD-L V, contact: j
i
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 69193-3478
(702) 798-2270
(702) 798-3146 (Fax)
The Technology Support Center fact sheet series is developed and written by
Clare L GktMtch, Lockheed Environmental Systems & Technologies Company, Las Vegas.

-------
&EPA
INTRODUCTION
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
November 1991
(Revised 1995)
TECHNOLOGY SUPPORT
uv-
Luminescence in
Field Screening
and Monitoring





nly 100 ppb

ft
A/U.80 ppb

ft
\ 50 ppb

I fWS\30ppb

° ppb
.Ji

350	400	450
Wavelength (nm)
Ultraviolet-visible
photoluminescence tech-
niques (including fluores-
cence and phosphorescence)
are gaining recognition as
useful methods for monitoring
Superfund, RCRA, and other
hazardous waste sites. The
Characterization Research
Division in Las Vegas (CRD-
LV) is active in the research,
development, and application
of these methods. This
document will focus on
fluorescence spectroscopy.
One application of this
method uses a fixed wave-
length excitation and records
the fluorescence emission
spectrum of the sample.
Another application, synchro-
nous fluorescence spectros-
copy scans both excitation
and emission monochroma-
tors to produce a simplified
spectrum, typically with one
peak per compound. This
allows polyaromatic hydro-
carbons (PAHs) to be sepa-
rated roughly into classes
according to the number of
fused rings. Both techniques
hold great promise as field
methods that are suitable to
the screening, characteriza-
tion, and monitoring of
contaminants at hazardous
waste sites. Although mostly
used for PAHs, phenols, and
pesticides, luminescence
techniques are also available
for metal chelates and
uranium.
With the emergence of field-
deployable, field-portable
instruments, and fluores-
cence sensors, luminescence
spectroscopy is joining the
list of easy-to-use, inexpen-
sive methods for evaluation
of contamination at hazard-
ous waste sites.
INSTRUMENTATION
FIELD USE
Luminescence techniques
are mostly used for the
analysis of aqueous samples,
though soil extracts may also
be used. The most fre-
quently used source is a
pulsed or continuous xenon
lamp which disperses light
through a grating. Alternative
light sources include mercury
lamps and lasers with either
fixed or tunable wavelengths.
For scanning spectrofluorom-
eters, the continuous spec-
trum of the light source is
dispersed by an excitation
monochromator, which can
The applicability of lumines-
cence methods to environ-
mental work is increasing
with greater availability of
compact instruments. The
CRDLV has field-deployable
fluorescence instruments. In
addition, a prototype of a
be scanned mechanically to
select a bandpass. Then, the
emitted light at each wave-
length is detected (usually at
right angles to the exciting
light) by an emission mono-
chromator coupled to a
detector. For quantification,
the fluorescence intensity is
compared to the response
from standards at various
levels on a calibration curve.
Identification, classification,
and quantification can be
performed by either fluores-
cence emission or synchro-
portable synchronous spec-
trofluorometer with a fiber
optic probe Is being devel-
oped for the CftD-LV through
an interagency agreement
with the DOE at Oak Ridge
National Laboratory. Using
these instruments, scientists
nous fluorescence spectros-
copy. The generated spectra
are simplified cross-sections
of excitation-emission arrays.
Both emission and synchro-
nous luminescence methods
are useful for characterizing
the source and concentration
of various polyaromatic
compounds. Current work on
PCBs and PAHs demon-
strates the usefulness and
sensitivity of luminescence
methods.
are able to identify and
quantify total PAHs ind
PCBs. These methods are
particularly good for environ-
mental samples requiring
relatively simple sample
preparation. Field use is
simple for this non-destruc-
(Continued)
1185EX91

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FIELD USE
(Continued)
tive technique. A typical field
instrument has two parts - the
spectrofluorometer and the
controlling computer. Each of
these units is portable and
suitcase-sized. The ease of
use and lack of elaborate
preparation steps makes UV-
vis luminescence an excels
lent choice for many hazardi
ous waste sites.
ADVANTAGES AND
LIMITATIONS
FUTURE
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UV-vis luminescence com-
pares very favorably with
many field techniques
because it has high sensitiv-
ity, is non-destructive, and
can analyze thermally labile
samples or heavy com-
pounds like tars and polar
compounds like phenols.
This technology has a proven
track record with the U.S.
Coast Guard where it is used
for oil spill identification.
Extending this application
into various environmental
areas is the next step. The
Advantages
Limitations
•	Very sensitive for aromatic
and polyaromatic analytes
•	Inexpensive
•	Water id not an interferent
•	Non-aromatic analytes
usually do not interfere
•	Little or no pretreatment
required
•	Simple microextraction
procedure
Needs derivatives for mo<*
non-aromatic analytes t
Interpretation may require
special training	f
Fluorescence yields vary I
CRD-LV is committed to the
careful application of existing
technologies to novel use^
environmental monitoring.
Current research should lead
to UV-vis fluorescence
instruments that are smaller,
cheaper, and more sensitive
to a wider range of analytes.
The development of reason-
ably priced small lasers may
eventually replace xenon
lamp sources. Rugged,
tunable lasers in the UV
range are being investigated.
Some monitoring can be
done with a filter fluoromete
saving the cost of the scarW
step. The most versatile
applications remain in the a
of emission and synchron0l
luminescence methods.
REFERENCE
Eastwood, D. and Vo-Dinh, T., Molecular Optical Spectroscopic Techniques for Hazardous
Waste Site Screening, EPA 600/4-91/011, U.S. EPA, Environmental Monitoring Systems
Laboratory - Las Vegas, 1991
FOR FURTHER INFORMA TION
For further information about UV-vis
luminescence methods, contact:
William H. Engelmann
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702)798-2664
For information about the Technology Sui
Cefft&r at CRD-LV, contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3476
(702) 798-2270
(702) 798-3146 (Fax)
«pj
The
Clare
Technology Support Center fact she0 series is developed and written by
9 L. Geriach, Lockheed Environment*! Systems & Technologies Company, Las Vegas.

-------
United States	Office of Research and	August 1992
Environmental	Development	(Revised 1995)
Protection Agency	Washington, DC 20460
TECHNOLOGY SUPPORT
&EPA Robotics Technology
in Environmental
Sample Preparation
INTRODUCTION
HARDWARE
The Characterization Re-
search Division in Las Vegas
(CRD-LV) is supporting the
use of robotics technology for
routine analyses of environ-
mental samples. The CRD-
LV currently uses two robot-
ics systems for inorganic
analyses. Robotics mini-
mizes the incidence of
operator error and provides
legally defensible documen-
tation following chain-of-
custody requirements.
Increasingly sophisticated
robotics technology coupled
with software that is user-
friendly makes robotics
attractive to laboratories that
are concerned about the
number of samples that can
be analyzed with consistently
high precision and improved
accuracy.
The CRD-LV will provide
technical document review
and consultation to EPA
In a sense, robotics hardware
is really analytical laboratory
hardware. When the robot is
used to weigh, dilute, and
prepare samples for chro-
matographic analysis, for
example, the hardware is a
table, a rack of sample jars,
an analytical balance, a
solvent vessel, a shaker, and
various arms and pipets that
allow the work to progress.
When a robotics network is
being designed, it is impor-
tant to consider parallel uses
Regions who are considering
the purchase of a robotics
system. Evaluations of
manufacturers bids and
demonstrations of the CRD-
LV systems are available
through the Technology
Support Center at the CRD-
LV. This technology has
increased the Laboratory's
ability to perform quick-
turnaround analyses that are
backed up by strong docu-
mentation.
that might be added for little
extra expense. This design
stage is critical in the cost
effectiveness of the system.
Scientists at the CRD-LV
worked with manufacturers to
ensure that the instruments
were customized for particu-
lar uses, but were not con-
fined to a single application.
An operator still weighs out
the samples for analysis
because environmental
samples are too complex for
the robot to judiciously
segregate. For a soil sample
containing fines, coarse
gravel, and a few miscella-
neous twigs, human over-
sight is needed. The analyti-
cal balance, however, is tied
UKD the robotics network so
that transcription errors are
eliminated. Therefore,
robotics reduces human error
but does not eliminate human
intervention.
1204EXS2

-------
SOFTWARE
FUTURE RESEARCH
Robotics systems come with
easily modified software
packages. Solvent amounts,
volume of internal standards
and surrogates, and time on
the shaker can be adjusted
easily. Software allows the
robot to recognize bar codes,
and to stop operation if a
sample is dropped or broken.
A strong round robin study
can be done when several
laboratories use the same
f Technology %.
2"PP°rt 0
robotics software. The
elimination of operator bias
gives a better indication of
the true sources of variance
in any investigation. The
correct robotics system
provides chain-of-custody
records, fraud detection,
simpler analytical QA, and
round-the-clock performance.
The robotics system can be
described as a computer -
with arms. As such, it is no
smarter than the designers
and operators of the systen
The robot is not foolproof b
merely fool-resistant. It will
follow orders, add solvents,
and shake samples. It
cannot differentiate betweei
HPLC grade and less pure
methylene chloride, for
example. The responsibility
for good laboratory practice
remains with the analyst.
Robotics usage will be
enhanced with increased
ability for error recovery,
allowing the system to know
when samples have been
switched, for example, and to
correctly match samples with
their weights. Artificial
intelligence and expert
system technology might be
coupled with robotics to give
users systems that are
capable of more intricate
sample handling and decision
making. Microwave digestio
applications and complex
extraction procedures may
soon be programmable at tl
robotics workstation.
REFERENCES
Hillman, D. C., P. Nowinski, M. A. Stapanian, J. E. Teberg, and L. C. Butler, "A Single Labors
tory Evaluation of a Robotic Microwave Digestive System", EMSL-LV, 1992.
FOR FURTHER INFORMATION
For further information on robotics technology, contact:
Dr. Larry C. Butler
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702)798-2114
A copy of a video illustrating the CRD-LV robot in action is available free to Agency users ^
L Butler.
For information about the services available through the Technology Support Center at Cf$
LV, contact:
Mr. Ken Brown, Director
Technology Support Center
U.S, Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2270
(702) 798-3146 (Fax)
?er faC'ShO0t ls developed and written by
Clare L. Gerlach, Lockheed Environmental Systems & Technologies Company,
Las Vega*

-------
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
March 1992
(Revised 1995)
TECHNOLOGY SUPPORT
&EPA
Guidance for
Characterizing
Heterogeneous
Hazardous
Wastes
INTRODUCTION
PLANNING THE
STUDY
QA/QC AND DATA
Quality
assessment
The U.S. EPA and the U.S.
DOE are interested in ad-
dressing the special problems
presented in sampling hetero-
geneous hazardous waste
ranging from physically
diverse samples from landfills
to chemically mixed waste
found at many sites. This
area of sampling and analysis
poses problems to field arid
laboratory personnel engaged
in the identification, classifica-
tion, and quantitation of
potentially hazardous
materials.
A recent workshop cospon-
sored by the DOE Officeof
Technology Development
and the Characterization
Research Division in Las
Vegas (CRD-LV) resulted in
a document that provides
guidance tor scientists
working in this challenging
area. Characterizing Hetero-
geneous Hazardous Wastes:
Methods and Recommenda-
tions (EPA 600/R-92/033) is
available to Agency person-
nel through CERI. This
document contains valuable
information about proven
protocols as well as innova-
tive technologies and recom-
mendations for further
research. It presents a typical
case study and a survey of
the statistics involved in
design and analysis.
This chapter establishes a
rational diagram to follow in
the sampling and analysis
scheme. It is a five-step
process: preliminary plan-
ning, DQO process, sampling
and analysis design, sample
collection and analysis, and
data assessment Sampling
heterogeneous matrices is
complex and presents a
challenge to those planning
the study.
Particular stress is placed on
asking the right questions at
the beginning of a study,
searching for any pertinent
historical data, and establish-
ing DQOs that are realistic.
Examples are provided that
prompt readers to look for
potential pitfalls in a sampling
scheme. Guidance is pro-
vided for the use of non-
traditional statistical sampling
plans and recommendations
are made for the establish-
ment of appropriate confi-
dence intervals.
In this chapter, the focus is
on quality assessment
strategies that can be used in
the sampling of heteroge-
neous matrices and in the
¦ !—t »ka euhiaaauent
neous matrices and in me
analysis of the subsequent
data. The importance of a
priori knowledge is stressed.
An effective quality assess-
ment process will provide
useable data without stipulat-
ing onerous procedures upon
the already overworked
sampling expert. The correct
use of QA/QC samples such
as repBcates, duplicates, and
co-located samples is
discussed. Field evaluation
samples ami field matrix
spikes arerecommended.
Even in unconventional
method*, fheuMOf well-
pianned QA/QC practices
can identify random or biased
error and trace the error to its
source.
The reader is refefeed to the
document A Rationale forthe
Assessment of Ghm in the
Sampling of Soit8(9f>M50Q/
4-004)13) and to th* software
package, ASSESS, available
through CIRlto Agency
users.
1131EX92

-------
SAMPLE
ACQUISITION
ANALYTICAL
LABORATORY
REQUIREMENTS
sg*TI0*.,.
This chapter specifies
sampling procedures that
should be followed when
sampling heterogeneous
hazardous waste - whether
contained or uncontained.
Contained waste is that found
in drums or boxes.
Uncontained waste is landfill
litter and debris piles that
exist at some sites. The
monitoring of regulated land-
fills is required by law.
Sometimes state monitoring
requirements are more
rigorous than federal guide-
lines.
Several questions arise when
sampling heterogeneous
-OGY
waste. Is it possible to obtain
a sample of sufficient repre-
sentativeness that the
resultant data will truly reflect
the type and level of contami-
nation at the site? Is it
correct to physically separate
samples before analysis?
Should this separation be
based on physical character-
istics or on contamination '
type? How can health risks
be fairly evaluated when the
contamination varies in level
from trace to high percent-
ages? Can homogenization
steps be taken without
compromising the quality of
the data?
These questions are ad-
dressed and guidance is
given in technologies rangid
from soil-gas measurement
and open-path FTIR to
geophysical methods and
aerial photography. Particu
lar emphasis is placed on
sample collection procedure
and on handling steps. Fiefc
screening methods are
discussed; X-ray fluores-
cence, vapor analyzers, and
various spectroscopic
techniques. Additional
discussion focuses on
radiography, gamma ray
assay, and neutron assay
methods.
This chapter deals with the
analysis of the samples as
they are received by the
analytical laboratory, if the
sample arrives as a
multiphase liquid or as a
collection of various solids,
decisions must be made
about the analysis. It is
crucial that any segregation
or homogenization of
samples be discussed with
the decision makers. The
DQOs should be consulted
again and, as always, QA/QC
plays a vital role in the
generation of useable data.
A flow chart is provided to
lead the reader through
several phases of the labora-
tory procedure. The consider-
ation of a priori knowledge is
important in the laboratory,
too.
Fusion methods are dis-
cussed for use in the analysis
of inorganic contaminants.
Neutron activation analysis is
suggested for some analyses
of radioactive samples.
Guidance is provided on the
choice of sample size and the
consideration of particle size.
A table compares Various
radiation screening devices.
A section on the special
requirements of mixed waste
samples documents the ne«
for further refinement of
analytical methods and the
need for proper safety
precautions. Waste dispose
at the analytical laboratory )
discussed and the reader is
reminded that help exists in
this area from the America^
Chemical Society's Task
Force on RCRA.
The importance of proper
reporting is stressed becaiti
the need for understanding
reporting requirements in
advance is often critical in f
success of a study.
FOR FURTHER INFORMATION
For further Information about the document, Characterizing Heterogeneous Hazardous
Methods and Recommendations (EPA/600/R-92/003) or to obtain a copy, contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. BwkonmentaJ Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Us Vega*, NV 89193-3478
(702) 798-2270
(702) 798-3146 (Fax)
Mr. (S.P.) John Mathur, EM-551
Office of Technology Development
Office of Environmental Restoration
and Waste Management
U.S. DOE
Washinoton. D.C. 20545
(301)353-7922
SlTrSEK's"r »*»><»	and written by
¦ Lockheed Environmental Systems & Technologies Company, Las Vegtfc

-------
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
February, 1992
(Revised 1995)
TECHNOLOGY SUPPORT
&EPA
INTRODUCTION
TYPES OF ERROR
Correct Sampling
Using the Theories
of Pierre Gy
The Characterization Re-
search Division in Las Vegas
(CRD-LV) is interested in the
optimization of sampling
protocof, sampling tools,
subsampling techniques, and
sample analysis. The
importance of obtaining
representative samples in the
field and retaining their
integrity throughout the
analytical procedures is
fundamental to the genera-
tion of meaningful data.
Because sampling correct-
ness and representativeness
is critical to the collection and
handling of environmental
samples, the CRD-LV has
hosted short courses pre-
sented by M. Francis Pitard
to explain and enforce the
theories of Pierre Gy relating
to sampling practice. The
inherent heterogeneity of
soils presents a particular
challenge to field personnel
who are responsible for
sampling hazardous waste
sites. This heterogeneity is
also a factor that must be
addressed by statisticians,
geostatisticians, and chemo-
metricians as they develop
sampling plans for the
location and frequency of
sampling. It affects the
manner in whictvanalytical
chemists subsamplein the
laboratory. Finally, heteroge-
neity influences the interpre-
tation of data and the deci-
sions made about the actions
taken to remediate contami-
nation at a site. The theories
of Pierre Gy present practical
sampling and subsampling
methods that can be applied
for little or no added expense.
Careful attention to these
techniques can result in
samples that better represent
the site and data that more
truly represent the sample.
True and complete homoge-
neity is impossible to achieve
because many factors,
including gravity, work
against it. But the extent of
heterogeneity and its effect
on environmental sampling
can be minimized. Estab-
lished methods from the
mining industry are appli-
cable to the sampling of soils.
The work of George
Matheron, father of
geostatistics, and Pierre Gy,
sampling expert, can provide
useful insights for environ-
mental scientists who are
faced with sampling a
complex matrix for trace
contaminants.
Pierre Gy's theory addresses
seven types of sampling error
and offers proven techniques
for their minimization. The
seven major categories of
sampling error cover differ-
ences within samples. Other
differences can exist, such as,
within space (covered by
geostatistics) and within time
(covered by chronostatistics.)
The internal sample errors are:
Fundamental Error: This is
loss of precision inherent in
the sample and includes
particle size distribution. It is
circumstantial error. It can be
reduced by decreasing the
diameter of the largest par-
ticles or by increasing the
sample volume.
Grouping and Segregation
Error: Error due to non-
random distribution of
particles, usually by gravity.
It can be minimized by
compositing an analytical
sample from many randomly
selected increments or by
properly homogenizing and
splitting the sample.
Long-range l—	,
Error. This is fluctuating and
non-random. It is spatial and
maybe identic by
variographic experiments and
can be reduced Uy taking
many tncFWTmrtw to Tornrw©
sample.
Periodic Heterogeneity
Error: This fluctuaflon error
is temporal In character and
can be minimized by
compositing samples correctly.
Increment Delimitation
Error: Error tied to inappropri-
ate sampling design and the
wrong choice of equipment.
Increment Extraction Error:
This error occurs when the
sampling procedure fails to
precisely ex&act the inlemied
increment Weil-designed
sampling equipment and good
frTftis error
Is the expression l^ss,
contamination, era) alteration
of a sampteor subeample.
this
problem.

-------
J
SAMPLE INTEGRITY
DEVICES
SUMMARY
To truly represent a lot (or a
hazardous waste site) a
sample must be both accu-
rate and precise. Obviously,
100% accuracy and precision
cannot be obtained.' It is
important to minimize the
error that is introduced in that
sample-taking and in the
subsequent handling,
subsampling, and prepara-
tion. tf large-scale heteroge-
neity is ignored in a sampling
design, data generated from
the preferentially sampled
material will never truly reflect
the character of the site.
Some sampling devices and
protocols preselect fines or
coarses. This error is very
serious in environmental
work where concentration is
fundamental to decision
making. For example, if the
action level for compound X
is 100 micrograms/ kilogram,
a sample containing very fine
particles coated with com-
pound X would exceed action
levels but a large rock of the
same sample weight would
not. But both samples cam*
from the same site, in fact,
from the same cubic meter 0
soil. If samples spanning all
particle sizes are sent to the
analytical laboratory, a very
confusing picture of the site
will emerge. When decision!
are made based on the
ensuing data, they will be
incorrectly made (or made
correctly by accident!)
Correct sampling devices are
essential to good sampling
protocol and to good labora-
tory practice. Pierre Gy
recommends scoops and
spatulas that are flat, not
spoon-shaped, to avoid the
preferential sampling of
coarse particles. Additional
care must be taken at the
analytical laboratory, where
error can be introduced by
poorly designed riffle split-
ters, spatulas, and vibrating
tools. It Is recommended that
the sample be subsampled
using a system of alternate
shovelling wherein a large
sample is "dealt out" into
several smaller piles. One
-------
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
September 1992
(Revised 1995)
*>EPA
Special
Analytical
Services
INTRODUCTION
site* s CREEK NPL
The Characterization Re-
search Division in Las Vegas
(CRD-LV) has an excellent
background in the prepara-
tion and analysis of non-
typical samples that require
special care, in-depth knowl-
edge, and high-tech instru-
mentation. The EPA Regions
are welcome to submit
special samples to the CRD-
LV through the Technology
Support Center.
Representative sampling and
subsampling present chal-
lenges to field and laboratory
personnel. The CRD-LV has
experience and expertise in
the handling of complex and
heterogeneous matrices and
in the interpretation of results
from non-routine samples.
The following examples
illustrate the wide range of
capabilities and analytical
services available through
the CRD-LV.
DOUBLE EAGLE, 4TH
ST. NPL SITES
At the request of Region 6,
the CRD-LV analyzed
complex mixtures of tar,
asphalt, oily soil, sludge, and
water samples from the
Double Eagle and 4th St.
NPL Waste Oil Sites. One
main goal was to use various
organic and inorganic mark-
ers to allow source identifica-
tion between the two sites.
Despite severe sample
heterogeneity problems and
matrix inconsistencies within
each site, numerous organic
and inorganic markers were
identified using ICP-MS and
GC/high resolution MS. This
allowed unambiguous source
identification of samples from
either of the two sites, it was
then possible to correlate off-
site wastes to one of the two
A decision to use complete
sample dissolution in closed
high-pressure digestion
vessels for the inorganic
indicator parameters paid off
because volatile osmium was
detected. This rarely de-
tected analyte would not
have been noticed if conven-
tional methods of sample
preparation had been used.
The expertise gained in
sampling, extraction, diges-
tion, and analyses of these
complex samples adds to the
existing experience at the
CRD-LV.
The CRD-LV received
unusual soil samples from
Region 3's Jack's Creek NPL
Site. The samples contained
"an unknown purple com-
pound". This compound was
highly soluble in ethanol and
other organic solvents but not
in water. Ethanol extracts
were analyzed by /CP-MS
with a focus on compounds
that could impart a purple
color (such as chromium,
nickel, and iodine). Iodine
was detected in significant
quantities and was verified in
several qualitative wet
chemistry tests as complexed
iodine. GC/MS analysis of a
methylene chloride extract of
the compound produced two
identifiable peaks. The most
likely match was leuco crystal
violet, a reduced form of the
aniline dye known as crystal
violet. The presence of
complexed iodine further
confirmed this fetentificatio*
as developed leuco crystal
violet. Through this series of
analytical deductions,
muMdlacipttnary scientists at
the CRD-LV were alto to
dentify the mystery com-
pound from the Jack's Creek
Site.
The Jack's Creek Site also
required analyses tor chlori-
nated dibonzofurans. These
compounds were success-
fully quantified in thepras-
ence of chlorinated
aipnenyiemer nnvffor6nc68
by careful deconvokition of
the QC/high resolution MS
resuiift. Quantification of
theMfurarts has not tradi-
tionally beat* attempted under
such conditions.
1318EX930DC
-------
INDIANA HARBOR
RCRA SITE
NORTH DRIVE NPL
SITE
INNOVATIVE
METHODS
Indiana Harbor is a RCRA
facility in Region 5. The
Region needs to classify the
sediments in the harbor to
decide on the eventual
disposal of dredged material.
Oily sediment samples had
been analyzed previously by
a CLP laboratory but the
results were inconsistent
between the total analyses
and the toxicity characteristic
leaching procedure (TCLP).
By using extra care in
sampling and homogeniza-
tion techniques, as well as
use of excellent laboratory
practices (ELP), CRD-LV
scientists were able to
provide the Region with
consistent results.
^ "Technology ^
o ^PP°rt Q
^ Proiect £
The North Drive NPL Site in
Region 5 features an area
contaminated with Prussian
blue (ferrous and ferric
cyanide compounds). Again,
routine CLP analyses had
yielded unsatisfactory results.
The Prussian blue com-
pounds at the site were found
to be mixed with sulfides
which distill along with
significant quantities of
cyanide. The traditional CLP
cyanide methods are inaccu-
rate in the presence of sulfide
interference.
CRD-LV scientists re-
searched alternate cyanide
methods that are less
affected by sulfide interfer-
ences. The ASTM method
for weak-acid dissociable
(WAD) cyanide gave results
that were consistent when
synthetic iron cyanide
solutions containing sulfide
interferences were analyzed
The North Drive Site sampler
are now being analyzed with
the method which is easier ti
use and holds promise for al
high-sulfide samples requir
ing cyanide analysis.
The CRD-LV is proud to
maintain the instrumentation
and personnel necessary to
perform innovative analysis
of difficult and unusual
samples. Teaming state-of-
the-art equipment with highly
specialized, multidisciplinary
technical staff enables the
Laboratory to provide high
quality service to the EPA
Regions. The staff at CRD*
LV is keeping current with t!
analytical demands of an
increasingly complex enviro
ment.
REFERENCES
Report on the Identification and Analysis of Potential Indicator Parameters for Sourcing Off-
Site Contamination (Double Eagle and 4th Street Refinery NPL Sites), EMSL-LV TSC-17, JuU
1992.
FOR FURTHER INFORMATION
For information about accessing the special analytlcaLservices available through the CRDL.V
Technobgy Support Center contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Us Vegas, NV 89193-3478
(702) 798-2270
(702) 798-3146 (Fax)
Dr. Don Betowski
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-21T8
For further Information on Special Analytical Services contact:
SA^^;f0V0C001 L- R°berte°n Dr. Edward M. Heithmar Tammy L. Jotf
(702)798-2212 (702) 798-2Jf5 (702)798-2626 (702)798-21^
The Technology Support Center fact sheet series is developed and written bv
Clare L. Gerlach, Lockheed Environmental Systems & Technologies Company,
Las Vegas-
-------
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
September 1991
(Revised 1995)
TECHNOLOGY SUPPORT
f/EPA
INTRODUCTION
Performance
Evaluation
Samples
v
II
¦
Quality assurance (QA) and
quality control (QC) are
integral features of the
Agency's programs for the
detection and measurement
of contaminants in the
environment. QA monitors
the planning, implementation
and completion of sample
collection and data-analysis
activities. The Characteriza-
tion Research Division in Las
Vegas (CRD-LV) has consid-
erable experience in the
design of effective QA
programs. The Analytical
Operations Center {AOC) of
the Office of Emergency and
Remedial Response has
been preparing Performance
Evaluation Samples (PES)
with advice from the CRD-LV.
AOC uses a Quality Assur-
ance Technical Support
pgg jnven7ory Complex PESs for a variety
of Superfund needs are
provided by the AOC through
QATS with oversight and
technical direction from the
CRD-LV. These samples are
usually single blind because
the physical appearance
probably alerts the analyst to
the fact that they are PESs
but the identity and concen-
tration of the analytes are not
known.
(QATS) contractor also
located in Las Vegas to
prepare the PES. The
incorporation of PESs of
known concentrations into a
study is useful for evaluating
the accuracy of the analytical
procedures for real samples.
The AOC is responsible for
the production and distribu-
tion of PESs; the Office of
Research and Development
(ORD) provides technical
direction and independent
oversight.
Through the QATS prograrp,
the CRD-LV is assisting in
the development, testing and
distribution of PESs. PESs
are available from QATS for
a wide range of contaminants
in various matrices. The
most frequently requested
The inventory of PESs
available from the QATS
includes low/medium organic
compound# in mm and in
soil, Mfei Inorganic
compounds tn water anew*
soil, chlorinated fitexlns or
dtoJdrwwrans to si# and in
sediments, tow concentration
PESs are water and soil
matrices with contaminants
that are encountered in the
contract laboratory program
(CLP). The CLP is also
managed by AOC.
PESs can be zero blind,
single blind, or double blind.
When the analyst knows that
a sample is a PES and also
knows the identity and
concentration of the analytes
of interest, the sample is zero
blind. Zero-blind PESs are
often called laboratory control
samples (LCS). When the
sample is known to be a PES
but the identity and concen-
tration of the analytes are not
known, the sample is single
blind. When the analyst is
not aware that the sample is
a PES, it is double blind.
and oH/water, and individual
aroclors in toil.
i (Mr HT^vi nv?fy f9 35
new metnoas are developed
for the preparation s

Wfj^wafv —
compounds & water, high
concentration inorganic
compounds in soil, sefl/o#, oil,
I-toss are fllied if the reefuire-
menUs general and is typical
of sewwal site categories.
The development of site-
specific PESs for a single site
is too expensive.
-------
PES BY SITE
CATEGORY
FUTURE PLANS
"Technology ^
§ ^Support §
^'roject ij-
%»~
The National Priority List
(NPL) recognizes more than
20 industrial site categories,
ranging from battery acid
sites to gasoline stations.
The similarity of contami-
nants within these site
categories is sufficient to
warrant PES batches that
address the needs of most
individual sites within a
category. The dissimilarity
between samples within a
category is usually a function
of characteristics of the
sample matrix.
The AOC, QATS, and the
CRD-LV work with the
Regional site managers to
provide PESs for various site
categories in a variety of
matrices. If a PES is not
available for a particular nee
AOC, QATS, and the ORD
investigate the feasibility of
designing a customized PEi
Advantages
Limitations
• Provides information
about accuracy
• Legally defensible
data
• Interlaboratory
comparisons
Difficulty matching
matrices
Visibility of PES
Application to other
situations must be
explored
The QATS is expanding its
PES inventory. The Target
Analyte Profiles (TAP)
currently being developed by
QATS describe sites by
category. This system is
based on the CLP Analytical
Results Database (CARD)
which contains a compilation
of analyte/concentration
information from Superfund
sites in the Regions.
Meeting the existing needs
for PESs and for technical
support in their use and
evaluation is a major goal, as
is responding to growing
Regional demands for quality
PESs within the hazardous
waste programs.
Another effort is the estab-
lishment of Regional reposi-
tories for PES. This inven-
tory will enable the Regions
to evaluate the performand
of contract laboratories by
comparing results obtained
for the same PES.
Working within AOC and
ORD guidelines, QATS is
ready to meet the needs or
the Regions.
FOR FURTHER INFORMATION
For further information on the PES available and hem to order them, contact:
Larry Butter
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702)798-2114
Mr. Mike Wilson, Project Officer (5304G)
U.S. EPA, Analytical Operations Center
Office of Emergency and Remedial RespoT
401 M Street S.W.
Washington, D.C. 20460
(703) 603-9029
For information about the Technology Support Center at CRD-LV, contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. EnvironmenM Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2270
(702) 798-3146 (Fax)
The Tattmotogy Support Center fact sheet series is developed and written by .
Clare L Qenach, Lockheed Environmental Sytstems & Technologies Company, Las
¦i
-------
SEPA
INTRODUCTION
"SKST""
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
November 1991
(Revised 1995)
TECHNOLOGY SUPPORT
Monitoring
Airborne
Microorganisms
The Characterization Re-
search Division in Las Vegas
(CRD-LV) is evaluating
methods for monitoring
airborne microorganisms.
Monitoring indoor air spans
several research areas
including radiochemistfy
(radon, low-level radiation),
analytical chemistry (formal-
dehyde, cleaning solvents),
and microbiology (fungi,
bacteria, and other microor-
ganisms). Through a coop-
erative research and devel-
opment agreement (CRDA)
with Dow-Coming, microbi-
ologists at the CRD-LV are
investigating the use of
various monitoring tech-
niques that assess the type
and extent of microbiological
contamination in indoor air.
It was necessary to create a
laboratory setting which
closely resembleda typical
room but which could be
controlled and monitored by
scientists who wished to
investigate various types of
contamination, air movement
patterns, and the efficacy of
methods for their removal.
This exposurechamber
(known locaHy as "the
plywood palace") is located in
a research laboratory at the
CRD-LV. The room is about
13'X13'X8' and is constructed
of plywood sheets with a 6-
inch insulation between the
outer and inner walls.
Since its construction in
1990, the room has served
as a test facility for various
research efforts. Principal
among these, so far, are
evaluations of methods for
monitoring the quality of
indoor air into which fungal
spores have been introduced.
Future efforts will include the
evaluation of various mitiga-
tion agents and indoor air
purification systems, the
effects of human afnd me-
chanical movement on the
dispersal of microorganisms
in an enclosed area, and
comparisons of testing and
monitorina oroeorfi
- — .-v* II
accurate evaluation of indoor
air quality.
The indoor air facility is a
custom-built room that has &
well-sealed viewing window
and an enclosed anteroom
that serves as a suiting-up
area for scientists donning
respirators and protective
clothing. The room has five
sampling trees made of
stainless steel and equipped
with thermocouples and
humidity sensors. Thus far,
all testing has been done in
an atmosphere at constant
temperature and humidity.
The air flow is 150 dm, which
is the standard recom-
mended circulation for indoor
air. The room is equipped
with a HEPA (high efficiency
particle air) filter that removes
airborne particles greater
than 1 um in diameter. The
room has a wood floor, that is
presently covered with carpet
to check the behavior of
airborne microorganisms in
the presence of absorbing
materials. The simplicity of
the room makes it a perfect
mini-lab, able to adapt to
various research require-
ments.
The equipment «»d to
measure the Mdeitf and,
pathways of indoor air
cortarrtnstton varies from
simple gravimetric methods
to expense n*$ifmical
samplers. The simplest
method for retrieving fungal
spores is the placement in
the room of Petri dishes
containing an agar medium,
The drawback
is that it relies on gravity and
therefore preferentially
samples larger species.
Samplers that use a vacuum
to draw indoor air onto an
agar coaled plate may err on
the side of lighter species. A
laser technique is being
evaluated, too. So far, the
jjn—ilr1- ' *—
9 wr
the detection of $1^ spores
is a six-stage sampler that is
a tieredbank of sieve-like
of this method spores.
Iaraer species at the ipp aM
reduce gradually la the
anroiyi
wSra 119V6
tse&Vrun that indicate this
method is the most precise of
the methods tested for
monitoring studies of fungal
spores.
H88EX9!
-------
ADVANTAGES AND
LIMITATIONS
The obvious advantage to
conducting monitoring
evaluations in a simulated but
typical room is that results
can be assumed to reflect the
performance of testing
equipment in a non-controlled
environment. The room itself
is easily changed to measure
the effect of various param-
eters, such as fluctuating
temperature and humidity,
the presence of carpeting,
the use of biocides, and
changes in the construction
materials of the room.
A limitation of this facility is its
inability to represent certain
indoor environments, such as
an open foyer, an older
edifice constructed of materi-
als that are no longer avail-
able, or an isolated situation
that may set the biological
stage for a new or unnotice<
microorganism.
The facility is a good workin
model that is flexible enough
to provide an excellent
testing ground for various
monitoring devices and
methods that target specific
microorganisms in typical
indoor air.
FUTURE
Questions continue to arise
about the quality of indoor air,
the nature of microorganisms
in an indoor environment,
and the effective use of
various biocides. The CRD-
LV will continue to test
monitoring techniques
designed to address these
concerns. Future work in this
facility will expand the
species list to include bacte-
ria as well as fungi. The
ability to characterize and
enumerate indoor air con-
tamination is the first step if1
solving an environmental
problem of widespread
concern.
REFERENCES
Biological Contaminants in Indoor Environments, P. R. Morey, J. C. Feeley, Sr., J. A. Otten,
eds., STP1071, ASTM, Philadelphia, PA, 1990
FOR FURTHER INFORMATION
For further information about the monitoring of airborne microorganisms, contact:
Mr. Stephen Hem
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2594
^'°A/V
%
echnology ^

For information about the Technology Support Center at CRD-LV, contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(708} 798-2270
(702) 798-3146 (Fax)
JSJfcK2K S,UP£°u cftltBr/act sheet series is developed and written by
Clare L Qmiach, Lockheed Environmental Systems A Technologies Company, Las Veg&4
-------
SEPA
INTRODUCTION
Background
p°tential uses
SjliRB
Development
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
April 1993
(Revised 1995)
Biosensors
For
Environmental
Monitoring
CRD-LV is conducting
research on biosensors for
environmental monitoring
applications. This research is
designed to address a critical
and growing need for
real-time and in situ monitor-
ing devices which can be
used at Superfund sites and
RCRA facilities as wed as for
A biosensor is an analytical
device composed of a
biological sensing element
(enzyme, receptor or anti-
body) in intimate contact with
a physical transducer (optical,
mass or electrochemical)
which together relate the
ground water monitoring.
Because biosensor technol-
ogy lends itself to fast,
economical and continuous
monitoring capabilities,
development of these
systems to complement
classical analytical measure-
ments is expected to result in
a substantial cost benefit,
especially when sample
concentration of an analyte to
a measurable electrical
signal. In theory, and verified
to a certain extent in the
literature, any biological
sensing element may be
paired with any physical
transducer. The majority of
reported biosensor research
The unique characteristics of
biosensors will allow these
devices to complement
current field screening and
monitoring methods such as
immunoassay test kits as
well as fiber-optic and
chemical sensors. For
example, enzyme-based
biosensors show the poten-
tial for continuous monitoring
of compounds such as
phenollcs in process
streams, effluents and
groundwater. Further, since
certain of these devices can
operate in high concentra-
tions of organics such as
methanol and acetonitrlle,
these biosensors show
promise for in situ monitoring
of mixed organic wastes.
Other potential applications
include down-hole or perim-
eter groundwater surveil-
lance as weH at process
stream monitoring for
turnaround time and cost per
analysis are important
issues. Biosensors are
currently being considered
for development for detec-
tion of environmental pollut-
ants such as polychlorinated
biphenyls (PCBs), chlori-
nated hydrocarbons, ben-
zene/toluene/xylene (BTX)
and pesticides.
has been directed toward
development of devices for
GDnicai markets; however,
driven by a need for better
methods for environmental
surveillance, research into
this technology is also
fxpanding to encompass
environmental applications.
remediation procedures.
Antibody-based biosensors
show the potential for
coupling immunochemical
specificity with recent ad-
vances in fiber-optics and
microelectronics. These
biosensors may yield instan-
taneous analysis of a wide
the nee*
£®^red for Immunoassay
A variety of laboratory . environnrc^pHutants.
prototype biosensors have ARhough fftecaic r^uire-
been reported which measure ments must 8®rmifor each
a fairly broad spectrum of fie Id monitoring scenario,
table.
fn
&ti
n the following
107SODcon
-------
FUTURE
DEVELOPMENT
(Continued)
Requirement
Specification Range
FUTURE
RESEARCH
Cost
Portability
Assay time
Personnel training
Format
Matrix
Sensitivity
Dynamic range
Specificity
$1-15 per analysis.
Can be carried by one person; no external power
1-60 minutes
Can be operated after 1-2 hour training period
Reversible, continuous, in situ
Minimal preparation for groundwater, soil extract,
blood and urine
Parts per million to parts per billion
At least two orders of magnitude
Enzymes/receptors:
specific to one or more groups of related compounds
Antibodies:
specific to one compound or closely related group of
compounds
tn addition to the basic and
applied research conducted
through CRD-LV, efforts
are currently underwayjgr
laboratory evaluation and
field testing of commercial
biosensors in preliminary
stages of development as
well as those which are "in
the queue" for introduction
into the commercial market.
REFERENCE
Biosensors for Environmental Monitoring, K. R. Rogers ft J. N. Lin, Biosensors &
Bioeleetronics 7,317-321. 1992.
J: Technology
o A T z
q ^Support q
J
FOR FURTHER INFORMATION
For further information about biosensors for environmental monitoring, contact:
Dr. Kim R. Rogers
Exposure Assessment Research Division
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2299
For information about the Technology Support Center at CRD-LV, contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Rdpearch Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2270, (702) 798-3148 (Fax)
The Technology Smiort Center fact sheet series is developed by Clare L. Qerlach, Lockheed
Environmental Systems & Tochnolaaum Cnmnanu i»
-------
¦SEFft
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
June 1995
TECHNOLOGY SUPPORT
EPA Training Programs
Available Through the
CRD-Las Vegas
'NTRODUCTION
The EPA is committed to providing
training for environmental scientists at
federal, state, and local regulatory agen-
cies. The EPA Characterization
Research Division-Las Vegas (CRD-
LV) of the National Exposure Research
Laboratory (NERL), strives to "transfer
its laboratory discoveries into products
and applications that contribute measur-
ably to environmental preservation and
the National economy." The CRD-LV
is part of the EPA Office of Research
and Development which has consider-
able expertise and experience in various
applications of analytical cbemistiy,
quality assurance procedures, and other
topics related to the monitoring and
characterization of hazardous waste
sites.
The CRD-LV has developed several
training courses that are available to
EPA employees and other federal, state,
and local government employees and
contractors whose work would benefit
from increased knowledge in the subject
areas. Funding arrangements must be
negotiated.
These courses are available to a suitable
class size at the CRD-LV or can be pre-
sented at any EPA Regional Office
upon request, if funding is available.
No more than three courses or demon-
strations cp be given on a specific
topic perfiscal year.
Taiget audiences include scientists and
a^paeers who require specific traini
or continuing education in the latest
yjL wmiuumg cuucauon m the latest
methods, and environmental decision-
makers whose responsibilities require
knowledge of a broad range of tech-
nologies.
<8300095
-------
LABORATORY
HELD
SOFTWARE
The CRD-LV has been a center of ana-
lytical chemistry applications - even
before there was an EPA! The laborato-
ry was established almost forty years
ago as the Public Health Services
Southwestern Radiological Health
Laboratory (SWRHL). SWRHL work
consisted of air monitoring for radionu-
clides and radioactivity whole body
counting for Nevada citizens living
downwind of the Nevada Test Site. In
1970, when EPA was created, SWRHL
became an ORD research laboratory and
was renamed the Western Environmen-
tal Research Laboratory. Since then
effort has been expended on developing,
evaluating, validating, and utilizing
advanced monitoring methods for haz-
ardous, radioactive, and mixed waste.
The Technology Support Center (TSC)
at the CRD-LV bridges the gap that
sometimes exists between research and
end users. Through the TSC, the EPA.
Regions are able to access the expertise
of the CRD-LV for special analytical
services and high-tech instrumental sup,
port during the monitoring and charac- i
terization of hazardous waste sites, j
including those regulated under '
Superfund and RCRA.
Analytical equipment at the CRD-LV j
includes a suite of chromatographic
instruments, high-resolution mass spec-
trometers, capillary electrophoresis
units, a fully equipped immunochemica
laboratory, and geophysical measure-
ment devices.
Training in the use of these instruments
will be arranged if there is sufficient
interest and if resources can be negotial
ed.
The CRD-LV provides the EPA
Regions with access to a growing num-
ber of field analytical instruments and
instruction in their use. When a Region
makes a request for technical support
from the TSC at the CRD-LV, a quality
assurance project plan (QAPP) is writ-
ten, a field crew is deployed, measure-
ments are taken, data are analyzed, and
the Region is supplied with a final
report detailing the findings and results.
Each stage of this process is carefully
researched and implemented according
to the latest technological guidance
available. A carefully written QAPP
can spell the difference between the
success or failure of a field analytical
procedure. By establishing data quality
objectives early in the process, expen-
sive repeat analyses and extra site
visits can be avoided. A field crew with
experience in using and modifying
portable analytical instruments can
reduce the need for expensive and less
immediate analytical procedures done at
a remote laboratory. This experience is
especially critical in the successful
application of innovative technologies.
Data analysis is integral to the success
of any field (or laboratory) effort. The
use of geostatistics, for example, can
provide much-needed information aboa
the spatial distribution of contaminatioj
at a site. The TSC provides the Regioi
with all pertinent documentation and
includes significant results and conclu-
sions in a final report. The technical
support provided by CRD-LV is legal*
defensible.
Training in field quality assurance (Q^|
procedures is important in the overall
education of those involved in samplxq
and analysis at hazardous waste sites
and in a variety of ecological monitor-
ing activities. The CRD-LV training q
field QA shows sampling personnel an
scientists
how to
extract the
most infor-
mation from
field analyti-
cal results.
Scientists involved in various programs
at the CRD-LV have developed comput-
er software packages that aid environ-
mental decision-makers at all stages of
site characterizttion.
The CRD-LV is able to provide trainm
on the use of the following software
programs:
See Software Continued on last
-------
HYDROGEOLOGICAL SITE
CHARACTERIZATION
ICP-MS DATA AUDIT
TRAINING
ON-SITE OA OF FIELD SAMPLING AND
FIELD CHEMICAL ANALYSIS
USE OF PERFORMANCE
EVALUATION MATERIALS
COURSE GOAL:
PREREQUISITES:
DESCRIPTION:
COST:
CONTACT:
UNDERGROUND STORAGE
TANK CHARACTERIZATION
The goal of the Underground Storage Tank Characterization course is to provide
instruction to personnel engaged in the characterization and monitoring of leaking
Underground Storage Tanks (USTs). The course will provide a background in the
methods and procedures used, as well as the regulations that govern
the areas surrounding these facilities.
None.
This 3-day course provides an overview
of the UST regulations, methods for
monitoring leakage from USTs, and a
survey of the current sampling and ana-
lytical methods and instruments used to
assess the level and extent of any leakage. Monitoring approaches include, but are
not limited to, gas chromatography, fiber optic chemical sensors, immunoassays,
and various "sniffer" instruments.
To be negotiated.
For information about scheduling the Leaking Underground Storage Tank
Characterization course, please contact:
Dr. Larry C. Butler, Training Program Director
CRD-LV
(702)798-2114
-------
HYDROGEOLOGICAL SITE
CHARACTERIZATION
ICP-MS DATA AUDIT
TRAINING
ON-SITE OA OF FIELD SAMPLING AND
FIELD CHEMICAL ANALYSIS
USE OF PERFORMANCE
EVALUATION MATERIALS
COURSE GOAL:
PREREQUISITES:
DESCRIPTION:
COST:
CONTACT:
The goal of the Use of Performance Evaluation
Materials course is to instruct personnel in the design
preparation, and use of performance evaluation
materials as part of a comprehensive laboratory
QA/QC program.
None.
This 3-day course will provide personnel with
instruction to enable them to design, prepare, and use
Performance Evaluation Materials (PEMs) for evaluat-
ing the performance of CLP and non-CLP laboratories.
The course targets EPA Regional personnel who design PE
programs, evaluate laboratories, review data packages, and prepare or use PEMs.
The course encourages the use of PEMs and provides an avenue for support of
Regional EPA efforts by CRD-LV. Specific topics covered include: selection of
PEMs; requirements and suitability of PEMs for specific cases or sites; suitability
of PE sample recipes for specific sites and problems; how to make PEMs; advan-
tages and disadvantages of single-blind versus double-blind PEMs; PEM introduc-
tion into the case or sample delivery group; interpretation and use of results; and
coordination of PE research results with CRD-LV.
To be negotiated.
For information about scheduling the Use of Performance Evaluation Materials
course, please contact:
Dr. Larry C. Butler, Training Program Director
CRD-LV
(702)798-2114
-------
HYDROGEOLOGICAL SITE
CHARACTERIZATION
ICP-MS DATA AUDIT
TRAINING
ON-SITE OA OF FIELD SAMPLING AND
FIELD CHEMICAL ANALYSIS
i
COURSE GOAL: The goal of the On-Site Quality Assurance of Field
Sampling and Field Chemical Analysis course is to pro-
vide training in the procedures involved in the preparation
and implementation of on-site field audits, with an /
emphasis on proper field sampling and field chemi- 1
cal protocols and related documentation.
PREREQUISITES: None.
DESCRIPTION: The goal of the course is to provide instruction that enables the students to
perform on-site field QA/QC audits. This 3-day course presents instruc-
tion on all aspects of the preparation necessary for an on-site visit to a field
site. The course emphasizes proper methods of sample collection, chemi-
cal analytical procedures, and related documentation. The course consists
of two sections: classroom discussion of the paperwork component of
field on-site visits, and a classroom exercise that provides a walk through
of a simulated field situation. While the course is specific to Superfund
Quality Assurance guidelines, it is useful to anyone who conducts field on-
site visits.
COST: To be negotiated.
CONTACT: For information about scheduling the On-Site Quality Assurance of Field
Sampling and Field Chemical Analysis course, please contact:
Dr. Larry C. Butler, Training Program Director
CRD-LV
(702)798-2114
-------
HYDROGEOLOGICAL SITE
CHARACTERIZATION
ICP-MS DATA AUDIT
TRAINING
COURSE GOAL: The goal of the ICP-MS Data Audit Training course is to train personnel in
the interpretation and auditing of ICP-MS data.
PREREQUISITES: Prior experience in auditing
inductively coupled plasma-
mass spectrometry (ICP-MS)
data packages is desirable, but
not mandatory.
DESCRIPTION: This 3-day course provides an
overview of the fundamentals
of ICP-MS Method
6020, including the
QA/QC requirements
specific to ICP-MS, and
the differences between ICP-MS and ICP-OES. The course also addresses
the use of the new QA/QC forms for ICP-MS. Since the potential for mol-
ecular interferences exists at many masses, much of the course is devoted
to recognition and correction of these interferences with elemental and
higher-level equations. Discussion will also focus on the use of internal
standards for determining data usability near detection limits, recognition
of matrix effects, and memory effect recognition.
COST:
CONTACT:
To be negotiated.
For information about scheduling the ICP-MS Data Audit Training course,
please contact:
Dr. Lany C. Butler, Training Program Director
CRD-LV
(702)798-2114
-------
HYDROGEOLOGICAL SITE
CHARACTERIZATION
COURSE GOAL:
The goal of the Hydrogeological Site Characterization course is to provide
a background in the various methods and approaches used by field person-
nel to assess the presence, type, and extent of subsurface hydrogeological
contamination at hazardous waste sites.
PREREQUISITES: None.
DESCRIPTION:
This 3-day course is based on the earlier Superfund University Training
Institute course on the same topic. It outlines various instrumental, proce-
dural, and statistical processes that are critical to successful monitoring of
the subsurface environment These methods include, but are not limited to,
geophysical methods, use of the geoprobe, soil-gas measurement technolo-
gies, and the use of geostatistics to obtain information from spatially
diverse data.

mmmmk
\ * A v i < , > A'
Distance (fMt)
COST:
CONTACT:
To be negotiated.
For information about scheduling the Hydrogeological Site
Characterization course, please contact:
Dr. Larry C. Butler, Training Program Director
CRD-LV
(702)798-2114
-------
SPECIALTIES
PROTOCOL
GUIDE TO INSERTS
The CRD-LV special-
izes in the correct
application of tradi-
tional and innova-
tiye monitoring
methods, and
the statistical
' quality
assurance proto-
cols that support these
methods. There are three branches at
the CRD-LV: the Analytical Sciences
Branch (ASB), the Monitoring Sciences
Branch (MSB), and the Radiation
Sciences Branch (RSB).
The ASB programs range from innova-
tive monitoring methods, such as ion
mobility spectrometry, immunochem-
istry, and capillary electrophoresis to
refinements of established analytical
procedures, such as gas chromatogra-
phy/mass spectrometry and inductively
coupled plasma-mass spectrometry.
The MSB features a remote sensing
program, with expertise in aerial pho-
tointerpretation and geographical infor-
mation systems. The EPA's ecological
monitoring effort, the Environmental
Monitoring and Assessment Program
(EMAP), is also a part of MSB.
The RSB supports some of the research
at the Nevada Test Site and is also an
EPA center for radiation monitoring,
such as ambient gamma radiation mon-
itoring and internal dosimetry.
The training program at the CRD-LV
can draw on the expertise of these pro-
grams. Courses can be tailored to meet
the specific requirements of a given
audience. Contact the director of the
training program for further details.
The courses described in this brochure
were developed for environmental sci-
entists and engineers whose work
requires additional knowledge in the
subject areas. Though the courses are
primarily intended for EPA employees,
they are open on an as-available basis
to other federal agencies, state and local
regulators, and government contractors.
To discuss the details of these course
offerings, contact the training program
director, Dr. Larry Butler, CRD-LV, at
(702) 798-2114 or Fax (702) 798-3146.
The inserts at the center of this docu-
ment describe five courses already
available through the training center at
CRD-LV. These courses are:
• Underground Storage Tank
Characterization
• Use of Performance Evaluation
Materials
• ICP-MS Data Audit Training
• Hydrogeological Site
Characterization
The locations and times for the CRD-
LV training courses are flexible. The
CRD-LV will try to meet the require-
ments of the student groups.
On-Site Quality Assurance of Field
Sampling and Field Chemical
Analysis
-------
SOFTWARE
Continued
Assess is an interactive program
designed to assist the user in statistical-
ly determining the quality of data from
soil sample analyses done on-site.
Scout is a user-friendly program devel-
oped by statisticians to identify multi-
variate or univariate outliers, to check
variables for lack of normality,
to graph raw data, and to output
the results of principal compo-
nent analyses.
Geo-EAS is interactive software devel-
oped to meet the needs of environmen-
tal scientists who work with spatially
distributed data, allowing them to bene-
fit from geostatistical tools without
becoming geostatisticians.
CADRE is a program used for data
validation by the Regions that
provides data analysts with
quick and reliable data for use
in decision-making at haz-
ardous waste sites.
THE FUTURE
The five courses described in the
inserts are the flagships of the CRD-LV
training program. New courses may be
developed on tape audit interpretation,
data validation (using the Regional
functional guidelines) or statistics,
health and safety issues in site work, or
hands-on courses in innovative
immunoassay test kit methods.
The CRD-LV is committed to its mis-
sion of technology transfer, technical
support, and high-quality training.
FOR FURTHER INFORMATION
For information about the courses available through the CRD-LV training pro-
gram, contact:
Dr. Larry Butler, Director
Training Program
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P. O. Box 93478
Las Vegas, NV 89193-3478
(702)798-2114
(702)798-3146 (Fax)
For information about the Technical Support Center (TSC), contact:
/
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Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2270
(702) 798-3146 (Fax)
This informational brochure was designed and developed by Clare L. Gerlach
Kit M. Peres, Lockheed Environmental Systems & Technologies Company,
Las Vegas, Nevada.
-------

BACKGROUND
United States
Environmental
Protection Agency
TECHNOLOGY support
Office of Research and
Development
Washington, DC 20460
May 1995
Mercury Preservation
Techniques
+A11CI3
The analysis of environmental
samples and the value of the
observed data are dependent
upon several factors:
» how representative the
sample is,
* how stable the sample is,
and
* how reliable the analytical
procedures are.
Historically, interest has been
focused on the stability of
mercury compounds, especial-
ly in aqueous matrices.
Factors that affect mercury sta-
bility include: the form of
mercury, the container materi-
al, the matrix, and the preser-
vation techniques.
The currently accepted method
in the contract laboratory pro-
gram (CLP) inorganic state-
ment-of-work (SOW) for
preservation of mercury sam-
ples requires a stabilization
with 2% HNOj with an
allowed holding time of 26
days prior to instrumental
analysis. Researchers at the
Characterization Research
Division in Las Vegas (CRD-
LV) have investigated the reli-
ability of 2% HNOj as a pre-
servative by studying the ana-
lytical data from synthetically
prepared Performance Evalua-
tion (PE) w?ter samples.
Aqueous quarterly blind (QB)
samples that were spiked with
inorganic forms of mercury
showed significantly low mer-
cury recoveries when analyzed
using 2% HNOj preservative.
Some researchers believe that
mercury ions bind to the reac-
tive sites on the surface of the
high-density polyethylene
(HDPE) water sample contain-
ers. Mercury ions are thought
to be reduced at these sites.
Then elemental mercury is lost
on or through the walls of the
plastic bottles. Mercury vapor
may also be lost when the bot-
tles are uncapped. Thus, mer-
cury ions are lost to subse-
quent analyses and reenter the
environment. Most low level
(less than 100 ppb) mercury in
synthetic environmental sam-
ples is lost within just a few
days using 2% HNOj preser-
vation.
The research challenge was to
find a method for stabilizing
aqueous mercury samples that
would be simple to use in the
field, effective at retaining the
true mercury concentration,
and could be used with all
major inorganic analytical
instruments without presenting
an interference. Though sev-
eral potential preservatives
were tested, only one was
found that would meet require-
ments.

-------
THE CRD-LV
SOLUTION
Researchers at the CRD-LV
found that a trace amount of
gold chloride (AuCl,) added to
the HNOj solution preserved
all forms of mercury. The
gold acts as a strong oxidizing
agent that converts or main-
tains mercury as mercuric ion
which remains in solution.
Optimization of this technique
revealed that a 1 ppm solution
of AuC13 in HN03 was suffi-
cient and did not affect any
other analytes or analytical
techniques. The AuCl, adds
no toxicity to the process or
waste products.
The price of gold is not a
major factor in the overall cost
of sampling and analysis
because such low quantities of
gold are needed. The cost for
the AuC13 is only about 10%
of the cost of the HNO, — or,
about S3 per 100 samples.
Inorganic samples preserved
with AuCl} can be analyzed by
anodic stripping voltammetry
(ASV), cold vapor atomic
absorption spectrometry
(CVAAS), and even by induc-
tively coupled plasma mass
spectrometry (ICP-MS), with-
out interferences from the gold
in solution. Previously, ICP-
MS was not used for mercury
analysis because the mercury
would deposit in the ICP-MS
sample introduction system
and be released during subse-
quent analyses (carryover).
The gold stabilization methcM
directly prevents deposition I
keeping all mercury in solva-
tion. The ability to use ICP-
MS for mercury analysis add
a valuable multi-element
instrument to the suite of me
cury detection systems.
There are additional benefits
using AuClj. Preservation
with AuCl, doubles the solu-
bility of silver in 2% HN<33
and therefore helps stabilize
silver. Silver is a relative iy
unstable element in water
pies and this added presex-va-
tion is a bonus.
APPLICATION
LIMITATIONS
When water samples are taken
for mercury analysis, field per-
sonnel should add HNO, with
AuCl,, to a final concentration
of 2% HNOj and 1-ppm
AuCl,. The current procedure
only calls for HNO,. The sam-
ples can then be shipped to the
analytical laboratory and ana-
lyzed without concern about
mercury holding times. Early
CRD-LV experiments indicat-
Experiments show that adding
concentrations of several ppm
AuCl, can precipitate Au and,
therefore, may threaten to
coprecipitate other analytes.
ed that mercury concentrations
in samples preserved with
AuCl, did not decrease even
after two years of storage.
Using the AuCl, preservative,
NIST trace mercury in water
standards (SRM 1641B) are
stable for at least 10 years (the
certificate value can still be
met when analyzing 10 year
old 1641B). By extending the
length of time samples can be
But even at 2 ppm (twice the
recommended concentration),
coprecipitation was not
observed in synthetic samples.
If field personnel inadvertently
held before analysis and by
providing a simple methcxi fi
ensuring sample integrity , th
AuCl, spiking procedure cou
save time, money, and et\h^p
data reliability. Costs to tyicM
tor and enforce mercury hold
ing times would no longer be
an issue when AuCl, preas^f^
tion techniques are used.
add twice the amount of
needed, there would be no
negative effect on the anatlyti.
cal results.
Dobb, D. E., R. C. Metcalf, R. W. Gerlach, and L. C. Butler, "Optimizing Reactions for Pres^^j
Mercury with Gold Chloride in Environmental Water Samples." Emerging Technologies in
Hazardous Waste Management VI, Proceedings of the I & EC Special Symposium, Americar*.
Chemical Society, Atlanta, GA, September 1994, pp. 1438-1441.
Dobb, D. E., G. A. Raab, J. T. Rowan, and L. C. Butler, "Preservation of Mercury in Envirom^-, .
Aqueous Performance Evaluation Samples," Emerging Technologies in Hazardous Waste
Management V, Proceedings of the I & EC Special Symposium, American Chemical Society v
Atlanta, GA, September 1993, pp. 426-429.
FOR FURTHER
INFORMATION
,^T,0/V
^ I echnology
o O - 2
o Support Q
%
"roject
^OGV^
Dr. Larry Butler
Research Chemist
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division-Las Vegas
P. O. Box 93478
Las Vegas, NV 89193-3478
(702)798-2114
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division-Las
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2270
The Technology Support Center fact sheet series is developed by Clare L. Gerlach, Lockheed
Environmental Systems & Technologies Company, Las Vegas.
-------
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
June 1993
(Revised 1995)
TECHNOLOGY SUPPORT
vvEPA
The Need:
Field-Portable Scanning
Spectrofluorometer
CRD-LV
Innovative
Technology
Field-portable instru-
ments are available for
the qualitative and
quantitative evaluation
of volatile organic
compounds and non-
volatile inorganic
elements. Compounds
that fall between these
volatility extremes have
received less attention
in recent years. And
yet these compounds
comprise a surprising
number of important
contamination catego-
ries at Superfund and
RCRA sites.
Polyaromatic hydrocar-
bons (PAHs) in com-
plex mixtures such as
oils, creosotes, and tars
are found on numerous
hazardous waste sites
and, because of their
high molecular weight,
present special chal-
lenges to analytical
chemists and instru-
ment developers.
These compounds have
relatively high lumines-
cence yields and,
therefore, can be readily
measured by spectroflu-
orometry.
A recent technology
that is in the production
prototype stage is the
Field-Portable Scanning
Spectrofluorometer
(FPSS). It is a light-
weight battery-operated
instrument that has
shown early promise as
a screening device for
petroleum oils, PAHs
and, especially, creo-
sotes.
Creosote (wood preser-
vation) and coal gasifi-
cation sites are wide-
spread, especially in the
southeastern United
States. These are
complex sites that
usually have various
PAHs in addition to the
creosotes. These
compounds are cur-
rently quantified by gas
chromatography but
their tarlike composition
makes them difficult to
detect and destructive
to columns and detec-
tors. The development
of a field-portable
instrument to rapidly
identify and quantify
PAH mixtures, such as
creosotes, oils, as-
phalts, or coal tars is
an important step in
filling a field analytical
niche.
The FPSS prototype is
ready for field demon-
stration and compara-
tive studies. It is
anticipated that the
FPSS will provide a
more rugged and less
expensive alternative to
traditional methods for
screening PAHs.
2016EX93ODC
-------
The Use:
Scientists working at
the Characterization
Research Division in
Las Vegas (CRD-LV)
have performed labora-
tory evaluations of the
battery-operated FPSS
developed by T. Vo-
Dinh and his co-work-
ers at Oak Ridge
National Laboratory.123
Table 1 shows the
physical characteristics
of the instrument.
The FPSS can perform
emission and synchro-
nous wavelength
scans. In the emission
mode, relatively low
detection limits are
achieved (Table 2).
The emission mode is
useful for the determi-
nation of total PAHs or
in identifying and classi-
fying oils. In the syn-
chronous mode both
the excitation and
emission monochroma-
tors are scanned simul-
taneously with a con-
stant wavelength offset.
The advantage to syn-
chronous mode is that it
separates spectra of
compounds with a
different number of
fused rings, sharpens
spectra, and allows the
relative amount of
various PAH classes to
be quantified.
The FPSS consists of
three parts: a small
Table 1. Physical Characteristics of the Field-
Portable Scanning Spectrofluorometer

SIZE
WEIGHT
Instrument
48 x 40 x 21 cm
11.5 kg

(18.5x11.5x8")

Battery Pack
31 x 18 x 15 cm
11.0 kg

(12x7x6")

suitcase-sized instru-
ment that houses the
optics and electronics,
a battery pack, and a
lap top computer used
for instrument control,
data storage and
analysis. The spectral
coverage of the instru-
ment is 210-650 nm.
The instrument param-
eters are chosen by the
operator who uses the
computer to control the
instrument.
The FPSS can be oper-
ated two ways: using a
standard fluorescence
cuvette cell or a bifur-
cated optical fiber. The
optical fiber attachment
is 2-meter long and
allows direct screening
of water samples. The
cuvette can be used
with liquid samples or
extracts of soils. When
the optical fiber attach-
ment is used, care must:
be taken to avoid inter-
ference from light. This
can be done by cover-
ing the sampling area
with a black cloth.
Table 2. Limit of Detection (S/N = 3)
SYNCHRONOUS
EMISSION SYNCHRONOUS
(cuvette)
(cuvette)
(fiber)
Perkin Elmer LS50 0.17*
0.02
24
(laboratory instrument)

FPSS prototype 3.5
0.55
1
* All concentrations ng/mL of anthracene
The Limits:
Some areas of concern
exist relative to the
successful operation of
the FPSS in a field
situation. The rugged-
ness of the optical
components is crucial
to the in situ applicabil-
ity of the system. The
unit was shipped from
Oak Ridge National
Laboratory to the CRD-
LV without affecting the
optical alignment or
electronics. The instru-
ment has been demon-
strated to withstand
normal handling in the
laboratory. The instru-
ment is ready to be
(continued on next page)
-------
The Limits:
(continued)
demonstrated at a
hazardous waste site.
The FPSS is particu-
larly suited to the
classification or identifi-
cation of oils or PAH
compounds. It can also
be used with site-
specific standards to
quantify total oils or
PAHs. It can be used to
determine relative
amounts of the PAH
classes present. In
rare instances, like
spills of solvents or
PAHs with very high
fluorescent yields and
sharp structures such
as benzo-(a)pyrene, it
can be used to detect
and quantify identified
PAHs. There is greater
spectral separation
capability when the
instrument is operated
in synchronous mode
but lower detection
limits can be achieved
using the emission
mode.
The Status:
Laboratory evaluations
and research efforts
have resulted in a draft
fluorescence method
for the analysis of
PAHs which is in the
final stages of accep-
tance by the American
Society for Testing and
Materials. A compari-
son of the optical fiber
mode and the standard
cuvette mode was per-
formed on samples of
anthracene in metha-
nol. This study showed
the cuvette mode to be
2-3 times more sensi-
tive than the optical
fiber mode.
Synchronous lumines-
cence has been dem-
onstrated to be useful
in characterizing crude
and fuel oils.4 The
technique can be used
to produce spectral
fingerprints for the
identification of oil
contamination types
and sources. The
FPSS proved its ability
in a study comparing
samples from an oil
spill with samples of the
source oil which were
provided by the U.S.
Coast Guard.
The FPSS has shown
considerable promise
for the classification
and quantitation of PAH
compounds and oily
mixtures. The next
step is to take the
portable instrument to a
hazardous waste site
where it can be evalu-
ated against standard
methods in a well-
planned experimental
design. The develop-
ment of the FPSS was
sponsored by the CRD-
LV and commercializa-
tion is being planned.
References: 1 T.Vo-Dinh, "Synchronous Excitation Spectroscopy" in Modern Fluores-
cence Spectroscopy, Vol. 4, Edited E.L. Wehry, Plenum Press, New York,
1981, pp. 167-192.
2 T. Vo-Dinh, "Synchronous Luminescence Spectroscopy: Methodology and
Applicability", Applied Spectroscopy, Vol. 36,576,1982.
3 J.P. Alarie, Vo-Dinh, T., Miller, G., M.N. Ericson, S.R. Maddox, W. Watts,
D. Eastwood, R.L. Lidberg, and M. Dominguez, "Development of a Battery-
Operated Portable Synchronous Luminescence Spectrofluorometer", in
press, (Review of Scientific Instruments).
4 K.J. Siddiqui, Lidberg, R.L., Eastwood, D., and Gibson, G., "Expert Sys-
tems for Classification and Identification of Waterborne Petroleum Oils",
Monitoring Water in the 1990s, Meeting New Challenges, ASTM STP 1102,
J.R. Hall and G.D. Glysson, Editors, American Society for Testing and
Materials, Philadelphia, 1991.
-------
The Contacts
For further information about synchronous luminescence spectroscopy,
contact:
Mr. William H. Engelmann, Manager
Advanced in Situ Monitoring Program
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2664
For information about evaluating the FPSS at a hazardous waste site (Superfund or
RCRA), contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2270
(702) 798-3146 (Fax)
The Technology Support Center fact sheet series is developed by Clare L. Gerlach,
Lockheed Environmental Systems & Technologies Company, Las Vegas
-------
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
January 1994
(Revised 1995)
SEPA
The Need
TECHNOLOGY SUPPORT
Immunochemical Analysis
Of Environmental
Samples
CRD-LV
Innovative
Technology
Field methods used for
detecting compounds of
environmental signifi-
cance traditionally have
been derived from
standard laboratory
methods. When labo-
ratory methods are
adapted to the field,
they are often relatively
slow, insensitive,
expensive, and require
bulky transportable
equipment and skilled
operators. There is a
need for rapid, sensi-
tive, low-cost, portable,
and simple field meth-
ods for analysis of
environmental samples.
Immunochemistry
offers those advan-
tages. The only spe-
cialized equipment
needed is a spectro-
photometer, microtiter
plates or test tubes,
precision pipets, and
immunologic reagents.
Commercial manufac-
turers sell kits for field
screening, and new
equipment and meth-
ods are being devel-
oped for rapid, accurate
field analysis of a wide
variety of analytes,
such as heavy metals,
dioxins, and PCBs, that
are found at Superfund
and RCRA sites. As a
result the regulator and
regulated communities
view immunochemistry
as a powerful technol-
ogy for screening
analysis of environmen-
tal contaminants.
Immunochemistry
includes techniques
such as immunoaffinity
chromatography and
immunoassay. Sample
preparations based on
immunoaffinity take
advantage of the
attraction between an
antibody and a specific
analyte. The procedure
has great potential for
cleanup of complex
samples like soils and
sludges. By rinsing a
sample over an anti-
body-treated surface,
chemists can isolate
particular compounds
that adhere to the
antibody. The isolated
compound is then
eluted from the immobi-
lized antibody and is
ready for analysis by
chromatography or
immunoassay. One
common immunoassay
is the enzyme-linked
immunosorbent assay
(ELISA). In this tech-
nique, the selectivity of
the antibody for the
analyte and the result-
ant antibody-analyte
complex is the basis for
the specificity of immu-
noassays.
1
9311-0146EX93O0C
-------
The Characterization
Research Division in
Las Vegas (CRD-LV) is
pioneering an investiga-
tion into the usefulness
of immunochemical
techniques for monitor-
ing the extent of con-
tamination in environ-
mental and biological
matrices. CRD-LV has
developed and demon-
strated several of these
techniques and be-
lieves that they hold
great promise for the
quantitative analysis of
target analytes for use
in ground-water surveil-
lance, in situ hazardous
waste site monitoring,
and assessment of
human exposure.
Current work involves
the analysis of chemi-
cals like PCBs,
nitroaromatics, and
certain pesticides that
are difficult to analyze
by other analytical
methods. CRD-LV has
sponsored two national
meetings that focused
on regulatory issues
and technological
advances in environ-
mental immunochemis-
try. These meetings
brought together gov-
ernment, industry, and
university scientists to
discuss problems of
mutual interest in the
field.
A 1993 Technology
Support Center project
at a Superfund site in
Region 5 demonstrated
the usefulness of
immunochemical
methods for screening
PCBs in soil and river
sediment. This project
was an example of
cooperation between
EPA, DOE, the state of
Michigan, and various
contractors. Two
immunoassays and a
chloride-ion specific
electrode were used on
site and the real-time
analytical results were
compared with stan-
dard GC results from
EPA method 8081.
Preliminary results
show good agreement
between the immuno-
assays and GC and
even stronger correla-
tion could be achieved
with tighter quality
control measures.
In addition, other EPA
offices have applied
immunochemistry for
screening and analysis
in their programs. The
Office of Water has
used immunoassays to
screen indirect discharges
of specific analytes for
permitting under the
Clean Water Act
(304h). Sample analy-
sis data may soon be
used for comparison
and compliance moni-
toring within selected
industries, such as
commercial laundries.
The Office of Pesticides
is looking at ways to
shorten the pesticide
registration process by
using immunochemistry
as a cost-effective
technology.
Other government
agencies and universi-
ties are studying immu-
nochemical methods.
The Food and Drug
Administration (FDA)
may use immunoas-
says to obtain data for
the calculation of safe
concentrations of
residues. A recent
university project used
immunoassays to track
contamination during
the 1993 Midwestern
flood. In applications
as diverse as organic
geochemistry and
military operations,
immunochemical
methods have been
used for volatile organic^
compound measure-
ment. The U.S. Depart-
ment of Agriculture
(USDA) is integrating
immunoassays into
rapid test procedures
for detection of resi-
dues in meat and
poultry. Results from
these tests will be usee]
in regulatory and
compliance programs
for veterinary drugs,
sanitation, and pest
control. The National
Institute for Occupa-
tional Safety and Healtti
(NIOSH) has applied
immunoassays to
herbicide research,
clinical analysis,
biomarkers, and im-
mune biomonitoring.
They use the methods
to detect morphine
factor, alachlor, atr-
azine, cyanazine,
metalachlor, and 2.4-Q,
State laboratories hav^
analyzed soil samples
and water from private
wells using immuno-
chemical test systems
for triazine (atrazine)
samples.
The results of EPA's
Superfund Innovative
Technology Evaluation
(SITE) studies indicate
-------
The Use
(continued)
The Limits
a strong correlation
between field immuno-
assays, laboratory
immunoassays, and
gas chromatography-
mass spectrometry.
Another field use of
immunochemistry that
is being explored at
CRD-LV, the personal
exposure monitor
(PEM), may revolution-
ize safety and exposure
requirements for work-
ers who deal with
hazardous chemicals.
Immunochemical
dosimeter badges can
be used to detect
pentachlorophenol and
nitroaromatics, and are
being developed for
parathion and
chloropyrifos. These
badges are lightweight,
inexpensive, quick, and
provide a real time
indication of exposure.
The use of immuno-
chemical techniques is
gaining acceptance in
the environmental
sciences. One need
that is being addressed
is that of specificity.
Frequently, immunoas-
says are available for a
class of compounds,
like PCBs. Specific
quantitation for each
component has been
difficult.
The development of
PEMs, for example,
must address the
question of diffusion of
chemicals through a
semipermeable mem-
brane, the optimum
concentration of the
antibody, detection
limits of the PEM and
quantitation by immu-
noassay, the efficiency
of the antibody in
capturing the analyte,
and the capacity of the
device.
Validation studies of
reproducibility, matrix
effects, field trials, false
negatives/positives,
and correlation with
other tests will assist
acceptance of immuno-
chemical methods at
Superfund and RCRA
sites. The legal defensi-
bility of immunochemi-
cal results is yet to be
determined.
Advantages and limita-
tions are summarized
below.
Advantages
Limitations
• Field portable
• User friendly
• Quick and inexpensive
• Potential for wide range of
analytes
• Useful for many matrices
• Low detection limits
• Separate immunoassay needed
for each analyte
• More complex analysis required
for quantitation of specific
analytes
• Long development time for new
antibodies and methods
The Status
One new avenue of
investigation is the use
of antibody-coated,
fiber-optic immuno-
sensors. Another
application is the
integration of robotics
capability for high
sample throughput and
the development of a
tiered analytical ap-
proach, i.e., biological
and environmental
samples, biomarkers,
target analytes, and
degradation products.
This system of analyti-
cal procedures will
enable scientists to
measure contamina-
tion at the source,
follow the fate and
transport of residual
amounts, and assess
(continued on next page)
3
-------
The Status
(Continued)
References
%
"roject yS

human exposure.
Multianalyte immunoas-
says that can identify
several analytes are
expected to expand the
desirability of immuno-
assay technology for
environmental use.
Work in this area is
already underway at
CRD-LV and else-
where. Other applica-
tions of immuno-
chemistry, such as
multianalyte optical
immunobiosensors and
biorefractometry, are
being developed.
Industry recently
formed the Analytical
Environmental Immuno-
chemistry Consortium
(AEIC), which is focus-
sing on performance-
based method guide-
lines, method valida-
tion, and formation of
consensus on regula-
tory and technological
issues. The National
Technology Transfer
Center (NTTC) offers a
vehicle for collaborative
studies. Cooperative
Research and Develop-
ment Agreements
(CRADAs) between
industry and the gov-
ernment can be used to
promote technology
development and
licensing of immuno-
chemical applications.
The CRD-LV has a
Technology Transfer
Office that is able to
coordinate CRADAs for
the development of
immunochemical
methods.
Immunochemical
Methods for Environ-
mental Analysis,
J. M. Van Emon and
Mumma, R. O., eds.
ACS Symposium
Series 442, Washing-
ton, DC, 1990, 229pp.
Immunochemistry
Summit Meeting II,
C. L. Gerlach and
D. A. Fuccillo, report-
ers. September 1 -2,
1993, Las Vegas, NV.
Internal Report to
EMSL-LV.
Immunochemical
Methods for Environ-
mental Analysis,
J. M. Van Emon and
V. Lopez-Avila, Anal.
Chem., Vol. 64, No. 2
1992.
For further Information about the Immunochemistry program at the CRD-LV,
contact:
Dr. Jeanette Van Emon
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702)798-2154
For Information about using Immunochemical methods at a Superfund or
RCRA site through the CRD-LV Technology Support Center, contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2270, (702) 798-3146 (Fax)
^ -r %
^ I echnology *2-
O ^"VPP°ft 0
The Technology Support Center fact sheet series is developed by
Clare L Gerlach, Lockheed Environmental Systems & Technologies Company, Las
4
-------
4>EFft
THE NEED
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
December 1994
(Revised 1995)
TECHNOLOGY SUPPORT
Ion Mobility Spectrometry
for the Analysis of
Soil-Gas Samples
CRD-LV
Innovative
Technology
0731odc94.1
Environmental scientists rec-
ognize the need to quantify
vinyl chloride and related
compounds of environmental
significance in soil gas at lev-
els of 1 ppb or lower. Cur-
rent field-portable methods,
like gas chromatography -
mass spectrometry (GC-MS)
and GC equipped with a vari-
ety of traditional detectors,
lack either the low cost, com-
pound specificity, or rugged-
ness required for successful
measurement techniques for
many of the analytes of
interest.
Ion mobility spectrometry
(IMS) has been used in vari-
ous laboratory applications
since the 1970s. It was adapt-
ed by the U.S. Army for use
in hand-held chemical agent
monitors (CAMs). The EPA
is interested in the application
of IMS to the area of environ-
mental risk assessment analy-
sis. Here, quick results at low
cost are essential to the suc-
cessful characterization and
remediation of hazardous
waste sites.
Vinyl chloride, other chlori-
nated gases, and many chlori-
nated solvents are regulated at
concentrations near the 1 ppb
level in soils and water.
These compounds are fre-
quently trapped in the soil-gas
spaces and are difficult to ana-
lyze because of the physical
problems of obtaining and
preserving the sample as well
O7310dc94
-------
as the challenges inherent in
the subsequent analysis.
The Characterization Research
Division in Las Vegas (CRD-
LV) and its cooperators at
Washington State University
(WSU) have conducted labo-
ratory studies on a field-
portable GC coupled with a
Fourier transform ion mobility
spectrometer (GC-FTIMS).
Results are very encouraging
and the next step is to test this
method in situ at a hazardous
waste site. The CRD-LV has
been investigating the use of
IMS for environmental sam-
ples since a Superfund
Innovative Technology
Evaluation (SITE) study in
1990 indicated that IMS, with
some refinements, could be
useful for the characterization
of environmentally significant
organic compounds at haz-
ardous waste sites.
Building on earlier work,
scientists at WSU and the
CRD-LV have developed this
new hyphenated technique
that enhances the power and
applicability of IMS. The
GC-FTIMS merges the sepa-
ration power of capillary gas
chromatography with the
sensitivity of ion mobility
spectrometry and incorporates
a Fourier transform to achie-v
-------
THE USE (Cont.)
and detected easily. Analytes
with low affinities can be mea-
sured when competing chemi-
cals with higher affinities are
not present. Thus, the com-
pounds in Table 1 are better
suited to analysis by IMS than
are compounds like hexane
and benzene. Varying humidi-
ty can result in the formation
of ion-water clusters that cause
errors in both the identification
and the quantitation of the tar-
get analyte. This obstacle can
be overcome by using GC
prior to high-temperature IMS.
Scientists working at WSU
and the CRD-LV have evalu-
ated the GC-FTIMS system in
the laboratory for various
compounds, especially vinyl
chloride. Table 1 provides a
partial list of analytes that can
be detected by IMS with low
limits of detection.
Experiments have been con-
ducted on improving the sensi-
tivity and selectivity of IMS.
These include experiments
involving the ion source for
IMS, and the refinement of an
electrospray needle (Wittmer
et al., 1994) to be used in
electrospray-ion mobility
spectrometry (ES-IMS).
Table 1. Some common compounds that are
detectable using GC-FTIMS.
• Benzyl chloride
• Halogenated compounds
(various)
• Hydrogen cyanide
• Nitro-compounds (explosives)
• Organophosphorus compounds
• Phenols
¦ Phosphorus trichloride
> Toluene diisocyanate
• Vinyl chloride
THE LIMITATIONS
IMS is sensitive to changes in
humidity, which result in ion-
water clusters that can cause
erroneous identification and
quantitation. This problem
can be addressed by coupling
GC to the IMS. Introduction
by GC is imperative to elimi-
nate interferences from the
other organic compounds in
the air. Though early labora-
tory work is encouraging,
GC-FTIMS is still in the
research stage. Its perfor-
mance at a Superfund or other
hazardous waste site remains
to be seen.
Another complication occurs
when analyte concentration is
too high. The ion chamber
can be saturated easily —
sometimes the instrument is
too sensitive!
Some variability has been
noted between various precon-
centrator tubes that are some-
times used in IMS work.
The multipoint calibration
curves used in some laborato-
ry studies indicate that, for a
Ni-63 ionization source,
linearity decreases as the ana-
lyte concentration increases.
The use of a photoionization
source, in contrast, is linear
over Ave orders of magnitude.
The use of Fourier transform
provides some ruggedness to
the analysis but may introduce
a sense of black-box signal
control. Though the prototype
instrument is not set up for
analyst intervention, that inter-
vention may sometimes be
warranted. The first few
demonstrations of the
GC-FTIMS system may bene-
fit greatly from the technical
input of an expert. The true
value of the instrumentation
will be seen when novice
users can rely on the results
obtained.
THE STATUS
The period of extensive labo-
ratory analysis is now at the
stage where the instrument
and methodology are ready for
field demonstration and vali-
dation. Laboratory research
will continue on the models
(notably, ES-IMS) that are not
at the demonstration stage yet.
Additional research may focus
on the use of IMS to analyze
soil samples, perhaps when
coupled with a headspace
method that would free up
trapped analytes prior to
detection.
-------
Dwarzanski, J., M. G. Kim, A. P. Snyder, N. S. Arnold, and H. L. C. Meuzelaar, "Performance
Advances in Ion Mobility Spectrometry by Combination with High-Speed Vapor Sampling
Preconcentration and Separation Techniques", Anal. Chim. Acta, Vol. 293, No. 3, 1994.
Hill, H. H., Jr., W. F. Siems, R. H. St. Louis, and D. G. McMinn, "Ion Mobility Spectrometry",
Anal. Chem., Vol. 62, No. 23, 1990.
Jones, T. L., H. H. Hill, Jr., G. Simpson, M. Klasmeier, and V. Lopez-Avila, "Determination of
Vinyl Chloride in Soil Gas Samples by Gas Chromatography Coupled with Ion Mobility
Spectrometry", to be presented at U.S. EPA's Field Screening Symposium, February 1995.
Wittmer, D., Y. H. Chen, B. K. Luckenbill, and H. H. Hill, Jr., "Electrospray Ionization Ion
Mobility Spectrometry", AnaL Chem., Vol. 66, No. 14, 1994.
FOR FURTHER INFORMATION
For more information about GC-FTIMS
Ms. Tammy L. Jones
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2144
For information about evaluating the GC-FTIMS system at a hazardous waste site (Superfund or
RCRA), contact:
Mr. Ken Brown, Director
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2270
(702) 798-3146 (Fax)
, contact:
Dr. Herbert H. Hill
Department of Chemistry
Washington State University
Pullman, WA 99164-4630
The Technology Support Center fact sheet series is developed by Clare L. Gerlach, Lockheed
Environmental Systems & Technologies Company, Las Vegas.
-------
v>EPA
THE NEED
United States Office of Research and May 1995
Environmental Development
Protection Agency Washington, DC 20460
TECHNOLOGY SUPPORT
Capillary Electrophoresis
for Environmental
Monitoring
CRD-LV
Innovative
Technology
Capillary
The Analytical Chemistry
Research Program of the
National Exposure Research
Laboratory's Characterization
Research Division-Las Vegas
(CRD-LV) is developing new
methods for determining toxic
and hazardous chemicals in
samples from hazardous waste
sites. This research is guided
by several goals for analytical
methods:
* Shorter analysis time to
reduce costs and improve
quality control procedures.
• Improved separations per-
formance and applicability to
a wide spectrum of analytes,
including nonvolatiles, as
compared with current tech-
niques based on capillary gas
chromatography (GC).
• Field-screening capability
to achieve faster results and
better coordination between
sampling and analytical work-
ers.
• "Green" chemistry tech-
niques that reduce the genera-
tion of laboratory waste (e.g.,
low solvent consumption)
while simultaneously reducing
personnel exposure to toxic
chemicals.
• Simple technology,
exportable to foreign countries
and applicable to a broad
range of analytes in a continu-
ous monitoring format.
These goals are summed up
by the phrase "cheaper, better,
and faster," and are being met
by an innovative separations
technology called capillary
electrophoresis (CE) that is
new to environmental analysis.
Traditional methods for intro-
ducing a sample into an ana-
lytical device have various
drawbacks. Liquid introduc-
tion of samples and liquid
41600C95
-------
THE NEED (Cont.)
chromatographies and elec-
trophoretic separations are the
more universally applicable
techniques since they do not
depend on volatility of ana-
lytes or have molecular
weight limitations. Thermally
labile and polar compounds
often deposit in the injector
systems of gas chro-
matographs (even cold on-
column retention gap sys-
tems) to degrade chromatog-
raphy, precision, and quantita-
tive accuracy. High perfor-
mance liquid chromatography
(HPLC) has attempted to fill
the need for liquid state sepa-
rations, but its application to
ionic organics, neutral
hydrophobic compounds, and
inorganic ions has not been
universal. CE is a separations
technique that can meet the
goals stated above while fill-
ing a central, cross-cutting
role in analytical chemistry
for polar volatiles, most
semivolatiles, nonvolatiles
(e.g., herbicides), inorganic
cations, inorganic anions, and
biomarkers (i.e., indicators of
exposure). Introduced in
1981, CE is now firmly estab-
lished as the technique of
choice for pharmaceutical and
biomedical analysis.
CE is easily interfaced with
optical detection methods
based on Uv-visible absorp-
tion, indirect detection (UV cr
fluorescence), and laser-
induced fluorescence (LIF)
detection.
CE methods that are applica-
ble to routine problems are
emerging, and EPA-approved
CE methods are anticipated
shortly. CE technology is
widely developed commercial-
ly, and EPA staff at CRD-LV
are confident that current CE
methods are sufficiently
robust to provide valuable
contributions to environmenta
assessment at the present time
THE USE
CE instrumentation is simple
(see illustration in the
brochure header). A fused sil-
ica capillary (typically 0.050
or 0.075 mm X 27 to 57 cm)
connects two buffer (elec-
trolyte) reservoirs. A high-
voltage power supply (ca. 30
kV) connects the reservoirs
via the buffer-filled capillary.
The technique has been micro-
miniaturized as "CE on a
chip", and it is capable of
adaptation to continuous mon-
itoring applications based on
fast separations (see below).
CE analyte bands travel with
flat profiles that produce
extremely high resolutions
(see Figure 1). Reported val-
ues usually range from
250,000 to 1,000,000 theoreti-
cal plates, with exceptional
values up to 2.7 million.
Cross-sectional flow profile
due to electroosmotic flow
Cross-sectional flow profile
due to hydrodynamic flow

Figure 1. Flow Profiles
These values exceed those
obtained with other liquid
phase techniques such as
HPLC, and equal or surpass
the best capillary GC tech-
niques. This extremely high
resolution permits separation
of many more analytes on a
given column, eliminating
chromatographic interferences.
Figure 2 illustrates some of
the principles involved in CE
and micellar electrokinetic
chromatography (MEKC)
which involves the addition of
surfactant molecules to the
buffer solutions. MEKC (also
called MECC) was introduced
by Terabe et al. in 1984.
Terabe et al. also introduced
applications of cyclodextrins
and urea in MEKC for
improving separations involv-
ing hydrophobic molecules.
Electrophoresis (i.e., the
migration or mobility of ions
in an electric field) accounts
for the movement of ions of
the appropriate charge toward
the cathode or anode in nar-
row bands. The electrophoret-
ic flow is shown in Figure 2
by a smaller, dark arrow. In
addition, an electroosmotic
(EO) flow exists that trans-
ports bulk liquid with buffer
from one reservoir to the other
depending on conditions.
Usually, for bare silica, an
excess of mobile positive
charge exists in solution
because of the ionization of
silanol groups on the silica
surface. The EO flow is illus-
trated by the large, white
arrow. This flow is character-
ized by a flat, piston-like pro-
file rather than the parabolic
flow characteristic of pres-
sure-driven systems. This
flat-flow profile results in
extremely narrow peaks and
high efficiency in CE. The
separation of neutral analytes
under MEKC is based on their
affinity for micelles (aggre-
gates of surfactant molecules)
that migrate under these con-
ditions. These micelles are
considered to form a pseudo-
stationary phase. Another
capillary format using EO
flow, electrokinetic chro-
matography (EKC), involves
the use of packed capillary
columns with C18 derivatized
silica particles forming the
stationary phase.
The fact that CE is based on
electromigration of ions
means that the technique
be of great value in determin-
ing inorganic ion concentra-
tions. The U.S. EPA Region
VII has approved a method for
determining hexavalent
chromium (Cr(VI)). Ionic
organic applications devel-
oped in the pharmaceutical
and biomedical areas include
separation of proteins and
amino acids. Applications to
-------
-------
THE STATUS
Current developments in
CE/MS at CRD-LV and else-
where focus on electrospray
ionization with quadrupoles,
double focusing instruments,
ion traps, and time-of-flight
mass spectrometers. Currently,
a cooperative agreement
between CRD-LV and an
external institution is awaiting
implementation (Ms. Tammy
Jones, Project Officer).
Laboratory evaluations and
research efforts have resulted
in at least one EPA CE method
for hexavalent chromium that
was approved in Region VII in
March 1994. Dr. W.C.
Brumley, Dr. Wayne Garrison,
ERL-Athens, as well as other
EPA and independent
researchers, have performed
considerable research into the
application of CE to environ-
mentally important analytes.
The results have been suffi-
ciently successful that the next
step is to apply the technology
to real-world samples. Once
the methods have been demon-
strated on these types of sam-
ples, EPA staff are interested
in soliciting requests to per-
form CE analyses in a field
setting. To submit environ-
mental samples for CE analy-
sis or to be considered for a
CE field demonstration, con-
tact Dr. Brumley or Mr. Ken
Brown, listed at the end of thi<
sheet.
REFERENCES
Anon., Introduction to Capillary Electrophoresis, Vol. I, Beckman Instruments, Fullerton, CA,
1991.
Anon., Standard Operating Procedure No. 3124.3B: Determination of Hexavalent Chromium in
Soil Using Capillary Electrophoresis, U.S. EPA, Region VII, Jan. 1994.
Brumley, W.C., "Qualitative analysis of environmental samples for aromatic sulfonic acids by hi
performance capillary electrophoresis," J. Chromatogr., 603, 267, 1992.
Brumley, W.C. and C.M. Brownrigg, "The eletrophoretic behavior of aromatic-containing organic
acids and the determination of selected compounds in water and soil by capillary electrophoresis
J. Chromatogr., 646, 377, 1993.
Brumley, W.C. and C.M. Brownrigg, "Applications of MEKC in the determination of benzidines
following extraction from water, soil, sediment, and chromatographic adsorbents,"/. Chromatogr
ScL, 32, 69, 1994.
Gaitonde, C.D. and P.V. Pathak, "Capillary zone electrophoretic separation of chlorophenols in
industrial waste water with on-column electrochemical detection," J. Chromatogr., 514, 389, 199q
Terabe, S., Micellar Electrokinetic Chromatography, Vol. Ill, Beckman Instruments, Fullerton r* a
1992. '
Yik, Y.F., C.P. Ong, S.B. Khoo, H.K. Lee, and S.F.Y. Li, "Separation of selected PAHs by using
high performance capillary electrophoresis with modifiers," Envir. Mon. Assess., 19, 73,1991.
xcKn°/v
^ I echnology "Z~
O (K Z
O T^upport q
A Project £
FOR FURTHER INFORMATION
For more information about applying CE to
environmental problems, contact:
Dr. William C. Brumley
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division-Las Vegas
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2684
For information about evaluating CE at a ha-^.
ardous waste site (Superfund or RCRA) or For
analysis of samples at a field site, contact:
Mr. Ken Brown, Manager
Technology Support Center
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Characterization Research Division-Las Vej
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2270
The Technology Support Center fact sheet series is developed by Clare L. Gerlach, with technical
contributions in the CE sheet by Nelson R. Herron, Ph.D., Lockheed Environmental Systems &
Technologies Company, Las Vegas.
-------
United States
Environmental
Protection Agency
Office of Research and
Development
Washington, DC 20460
July 1995
&EPA
TECHNOLOGY SUPPORT
Robust Statistical Intervals
for Performance
Evaluations
innovative
Technology
INTRODUCTION
Environmental samples collected at Superfund sites
are routinely analyzed by the various commercial
laboratories participating in quality assurance/quality
control (QA/QC) programs such as the Contract
Laboratory Program (CLP) of the U.S. EPA. The
EPA Superfund CLP periodically evaluates, through
the performance evaluation (PE) quarterly blind
(QB) studies, the competence of participating labora-
tories in the quantitative analysis of prepared materi-
als. Identically prepared PE samples are sent to par-
ticipants. PE samples contain amounts of various
organic or inorganic compounds known only to the
evaluator. Laboratories are expected to report ana-
lytical results that are relatively close to the known
amount However, in practice, the recoveries report-
ed by the participants may differ significantly from
the "true" spiked amount
In a PE study, the objective may be to obtain: (1) an
interval estimate (LCL, UCL) for the overall mean
recovery {where LCL and UCL represent the lower
and upper confidence limits for mean, fi, respect-
ively), (2) an interval estimate (LSL, USL) within
which the majority of the participants are expected
to report their analytical results (where LSL and USL
simultaneous limits, respectively), or (3) an interval
estimate (LPL, UPL) for a delayed result, Xq, report-
ed by a participant (where LPL and UPL represent
the lower and upper prediction limits, respectively).
These intervals are significantly different from each
other and care must be exercised to use them
appropriately. For example, at a polluted site the
objective may be to obtain a threshold value estimat-
ing the background level contamination prior to any
activity that polluted the site. Here, the upper simul-
taneous limit* USL, and not the upper confidence
limit, UCL, for the population mean may be used. It
is inappropriate to compare an individual observa-
tion, Xj, with the UCL for the population mean, fi,
and expect an adequate coverage for all of the values
of x^ as is sometimes mistakenly done in practice.
There are two main issues that need to be consid-
ered. First, an adequate interval estimate should be
used for a typical application. The use of the confi-
dence interval (CI) for the mean, n, or a prediction
interval for a single future observation is inappropri-
ate when the objective is to obtain a statistical inter-
val providing simultaneous coverage for the majority
of the participants. The test-statistics and the associ-
ated critical values change from application to appli-
cation. Secondly, appropriate statistical methods
need to be used to obtain robust and resistant esti-
mates of the population mean, fi, and variance, a2.
It is important that the degrees of freedom (df) be
computed accurately by making the appropriate
adjustment for the outliers. All of these measures,
when considered collectively, result in more accurate
and reliable interval estimates.
Scientists at the National Exposure Research
Laboratory's Characterization Research Division in
484odc95
-------
INTRODUCTION
(Continued)
THE CURRENT
PROCESS
THE PROPOSED
PROCESS
Las Vegas (CRD-LV) have studied the CUP
database extensively and have developed improved
methods for assessing some QA measurements.
Chief among these improvements is a more robust
statistical method, based on simultaneous confidence
intervals, for evaluating the performance of the par-
ticipating laboratories in the QA/QC programs of th-»
U.S. EPA.
Let Xj, Xy..., xn represent the recoveries of a certain
compound reported by the n participants in a typical
PE study. The classical maximum likelihood esti-
mates (MLEs) of population mean, ft, and standard
deviation (sd), a, are the sample mean, x, and sam-
ple sd, s, respectively.
The U.S. EPA evaluates the analytical results report-
ed by the participants using statistical quality control
(SQC) techniques based on the classical MLEs, x
and 5. The classical estimates, x and s2, get distorted
in the presence of outliers and may result in unreli-
able and imprecise estimates of the above-mentioned
intervals. Thus, the outlying observations inherent
in most environmental applications can distort the
entire estimation process, which in turn can result in
incorrect decisions. The robust statistical intervals
should be used when outliers are present.
Horn et al. (1988) used the Biweight influence func-
don to obtain a robust prediction interval and recortj
mended its use to assess the performance of afuture~
(delayed) result reported by a single participant in a
PE study of the U.S. EPA. However, in PE studies
one of die main objectives is to obtain adequate
acceptance regions within which most of the particle
pants are expected to report their analytical results
simultaneously. The prediction interval currently
used is not appropriate to provide simultaneous cov^
erage for the majority of the participants. Moreover
the Biweight function does not perform well in sam J
pies of small sizes (/k 15). In the current Biwejgt,t~
procedure, no adjustment for the outliers is made in
the computation of the df used to obtain the critical
values of the associated test-statistics and, conse-
quently, inflated df are used to obtain these critical
values.
A more statistically rigorous approach to determine
misquantified analytes in PE studies has been dis-
cussed by Singh and Nocerino (1993). Comparisons
are made with the existing techniques. The "pro-
posed" PROP acceptance interval is a simultaneous
confidence interval with a built-in outlier detection
criterion. The PROP simultaneous confidence inter-
vals: (1) use the robust estimates of population
mean;(M, and variance, o2, which are not distorted
by the presence of multiple outliers (Singh, 1993),
(2) use more accurate estimates of df to obtain criti-
cal values of the associated test-statistics, and (3) by
definition, are better suited for such PE studies and
provide adequate simultaneous coverage for the
majority of the participants. Some of these intervals
are given as below. In the following equations, x *,
s*, and wsum refer to the robust estimate of ft, the
robust estimate of o, and the sum of the squared
weights, respectively, and are given by:
• The (l-a)100% confidence interval (LCL, UCL)
for the population mean, ft, is given by:
P(j* a + =
Vwsum Vwsum (2)
where t^ ^ represents the critical value from the
Student's t-distribution.
• The (1-a) 100% simultaneous confidence inter-
val (LSL, USL) for the majority of the participants
is developed as follows. Let d represent the a
(100%) critical values for the distribution of
(d ?). The simultaneous interval with a built-in
outlier identification criterion is given by
P (max(d ?)*d^a) = 1 - a, or equivalently, given
by the probability statement (Singh and Nocerino
1993),
x * = 2 Wj (di)x/2 Wj (dj)
and
s*2 = 2 w2 (djXxj - x *)2/df
(1)
P(**-S*dm,as Xi S
x * + s* d^a; i=l, 2,..., n) = 1 - a
(3)
where the weights are obtained using the
PROP or the Huber (Singh, 1993) influence
functions.
The distances, d 2 are given by d ? = (x; - x)2/s2 and
are identically distributed as a beta distribution:
• The (1-a) 100% prediction interval, (LPL, UPL),
for a future observation, Xq, is given by:
P(**-W2S*V^+1SX0S
n— (4)
**+tdf,a/2S* *wsum + 1) = 1 a
((n-l)2/n) £ (1/2, (n-2)/2)
-------
AN EXAMPLE
The following data set from a QB study illustrates
the differences among the above-mentioned interval
estimates. Using the analytical results reported by
43 laboratories for the semivolatile chemical, 4-
methylphenol, the computations for the various
intervals with a confidence coefficient (CC=l-a) of
0.95 are summarized in Table 1. The estimated df
obtained using the PROP procedure is df=34.39.
This is expected because of the reduced weights
assigned to the outlying observations. Using
Iglewicz's (1983) recommendation, one might use a
substantially smaller number of df, (0.7)(42) - 29.
Notice that the PROP sd is also much smaller, again
due to the negligible contribution of the outliers.
Figures 1 and 2 show the classical and robust simul-
taneous intervals. The classical interval in Figure 1
is distorted by the outlying observations (e.g., num-
ber 28, circled in the figures). The robust interval
estimate of Figure 2 is not influenced by the oudiers
and provides appropriate simultaneous coverage to
the majority of the participants.
It should be emphasized here that the outliers do not
necessarily represent poor performance laboratories
(bad values). In a typical PE study, a high discor-
dant recovery close to the true spiked amount may
indicate extremely good performance by the associ-
ated participant. However, consistent occurrences of
such high values for the same participant in several
PE studies may call for an examination regarding the
appropriate use of the analytical method. In any
case, all of the outliers, low or high, should be
down-weighted appropriately so that the resulting
estimates will correspond to the estimates of the
parameters of the dominant population representing
the majority of the participants.
The procedure described here: (1) identifies multi-
ple outliers, (2) uses appropriate test-statistics, (3)
computes the adjusted df associated with the test-
statistics by assigning reduced weights to the outly-
ing observations, and (4) provides more precise and
accurate estimates of die underlying population
parameters and the associated intervals. The accep-
tance intervals based upon the PROP method result
in higher probabilities of correctly estimating the
performance of a laboratory. Using the PROP
method, EPA data analysts can appropriately assess
the performance of a member laboratory in a PE
study by considering all of the relevant factors that
affect bottom line performance. The computations
and graphs for these intervals were obtained using
the Scottt software package developed by Lockheed
Environmental Systems & Technologies Company
for the U.S. EPA.
Table 1. Sampling Statistics and Intervals Obtained Using the Fonr Estimation Procedures for the PE
Analytical Results Data Set Reported by 43 Laboratories Participating in the CLP (CC=0.95).

df
mean
sd
LCL
UCL
LPL
UPL
LSL
USL
MLE
42.00
27.56
5.38
25.90
29.21
16.57
38.54
11.05
44.06
Huber
40.49
27.83
4.62
26.40
29.26
18.38
37.27
13.72
41.93
PROP
34.39
29.01
2.78
28.08
29.93
23.29
34.73
20.72
37.29
Biwt
42.00
28.38
4.56
26.98
29.78
19.07
37.69
14.40
42.36
47.57"
95% USL. la 44.0627
36.96-
>
>
>
>
V
>
>
>
>
>
>
>>*
>
>
> 2
%
>
>
>
>
26.36
A A A A A
A * A A A

A ^ Avarag* is 27.5581
Std. Skv. is 5-3821
A,
15.75-

95% LSL Is 11.0536
( 28 J
5.14-
>iii
-3.62 9.09 21.79 34.49 47.2
Control Chart (Simultaneous for all observations)
4840odc96F)g 1
Figure 1. Classical simultaneous interval for 4-methylphenol.
-------
40.9
-I 32.13+
5
£
\u
s
4
E
g 23.36
0
1
14.58+-
5.81
95% USL Is 37.2901
iai_
A A
A ^27A
A A
aa A
A AAA A
A
. A
~S A A A
A A
Average Is 29.0061
Std. Dev. Is 2.7781
95% LSL Is 20.7221
^ A>
15
*34
H-
-+-
A
28
-t-
-3.62
9.09 21.79 34.49
Control Chart (Simultaneous for all observations)
47.2
Figure 2. Robust simultaneous interval for 4-methylphenol.
REFERENCES 1- Horn, P. S., Britton, P. W., and Lewis, D. F., "On the Prediction of a Single Future Observation from a
Possibly Noisy Sample," The Statistician, 37,165-172,1988.
2. Iglewicz, B., "Robust Scale Estimators and Confidence Intervals for Location," in Understanding
Robust and Exploratory Data Analysis, Hoaglin, D.C., Mosteller, F., and Tukey, J.W., eds., New York
John Wiley, 1983.
3 Singh, A., "Omnibus Robust Procedures for Assessment of Multivariate Normality and Detection of
Multivariate Outliers," in Multivariate Environmental Statistics, 445-488. Patil, G. P., and Rao, C. R>
eds., North Holland/Elsevier Science Publishers, 1993.
4. Singh, A., and Nocerino, J.M.," Robust QA/QC for Environmental Applications," Proceedings of the
Ninth International Conference on Systems Engineering, Las Vegas, Nevada, 370-374,1993.
FOR FURTHER INFORMATION
^ "Technology "3?:
q upport O
OGV
For information about the Technology
Center at the CRD-LV, contact:
Mr. Ken W. Brown, Director
Technology Support Center
U.S. EPA, CRD-LV
P.O. Box 93478
Las Vegas, NV 89193-3478
(702)798-2270
For more detailed information about the correct use of
robust statistical intervals, contact:
Mr. John Nocerino
U.S. EPA CRD-LV
P.O. Box 93478
Las Vegas, NV 89193-3478
(702)798-2110

-------
United States Office of Office of Solid EPA/540/4-91/005
Environmental Protection Research and Waste Revised August
Agency Development and Emergency 1992
Response
•SEFA Ground-Water Issue
SURVEY OF LABORATORY STUDIES RELATING TO
THE SORPTION/DESORPTION OF CONTAMINANTS
ON SELECTED WELL CASING MATERIALS
Jos6 L. Llopis1
INTRODUCTION
The Regional Superfund Ground Water Fo-
rum is a group of ground-water scientists
representing U.S. Environmental Protection
Agency's (U.S. EPA's2) Regional Offices, or-
ganized to exchange up-to-date information
related to ground-water remediation at haz-
ardous waste sites. Well casing materials
used at hazardous waste sites is an issue
identified by the forum as a concern of
CERCLA decision makers.
To address this issue, this paper was pre-
pared through support from the Environmen-
tal Monitoring Systems Laboratory-Las Vegas
(EMSL-LV), under the direction of J. Lary
Jack, with the support of the Superfund Tech-
nical Support Project. For further information,
contact Ken Brown, EMSL-LV Center Direc-
tor, at FTS (702) 798-2270 or J. Lary Jack at
FTS (702) 798-2270.
All aspects of a ground-water sampling pro-
gram have the potential to affect the composi-
tion of a ground-water sample. The potential
for the introduction of sample error exists from
the time drilling commences and continues to
the time water samples are analyzed in the
laboratory. The high degree of accuracy
(parts perbillion (ppb) range) required of some
chemical analysis dictates that all potential
sources of error of a ground-water sampling
program be identified and sources of error in
such aspects be minimized. One potential
source of error is the interaction of the ground-
water sample with material used in well casings
for monitoring wells. Well casing materials may
introduce error in a sample by interacting with
water while it is still in the well and altering the
water composition. Proper selection of casing
materials used for ground-water monitoring
wells is critical in minimizing errors introduced
by this interaction. This paper is a survey of
scientific studies related to a specific process
which potentially affects materials used to pro-
duce monitoring well casings and screens.
This paper should not be exclusively used to
select the proper well casing/screen material
for a site specific situation. Other factors must
be considered into the selection process, in-
cluding: site specific water chemistry, sub-
strate physical bearing properties, formation
conductivity, design life of monitoring well,
presence of NAPL's, etc.
Selection of the proper casing material for
monitoring wells has been a subject of much
controversy since the publication of the U.S.
EPA's Resource Conservation and Recovery
Act (RCRA) Ground-Water Monitoring Techni-
cal Enforcement Guidance Document (TEGD)
(U.S. EPA 1986). The TEGD suggests the use
of polytetrafluoroethylene (PTFE, Teflon®) or
stainless steel (SS) for sampling volatile organ-
ics in the saturated zone and further states
"National Sanitation Foundation (NSF) or
American Society for Testing and Materials
(ASTM) approved polyvinylchloride (PVC) well
casing and screens may be appropriate if only
1 Geotechnica! Laboratory, Department of the Army Waterways Experiment Station, Corps of Engineers, 3909 Halls Ferry
Road, Vicksburg, MS 39180-6199
2 For a list of abbreviations, see page 15.
^T,0A,
^ "P
^ I Ktmology T~
O A Z
O JjkWort O
'%F~ J
Superfund Technology Support Center for
Monitoring and Site Characterization
Environmental Monitoring Systems Laboratory
Las Vegas, NV
Office of Sdid Waste and Emergency Response,
US. EPA. Washington, D.C.
Walter W. KovaBck, Jr., Ph.D„ Director
Printed on Recycled Paper
-------
trace metals or nonvolatile organics are the contaminants antici-
pated".
SOURCES OF ERROR
Error can be introduced into the ground-water sample by casing
materials with several processes including:
a. Chemical attack of the casing material.
b. Sorption and desorption.
c. Leaching of the casing material.
d. Microbial colonization and attack (Barcelona et al., 1985)
Before proceeding further, it is necessary to define the terminol-
ogy used in this report. The terms "sorbed" or "sorption" are used
many times in the literature to refer to the processes of adsorp-
tion and absorption especially when the exact mechanism is not
known. Adsorption is defined as the adherence of atoms, ions,
or molecules of a gas or liquid called the adsorbate onto the
surface of another substance, called the adsorbent; whereas,
absorption is the penetration of one substance (absorbate) into
the inner structure of another called the absorbent. In this report,
rather than distinguishing between the processes of adsorption
and absorption, the term sorbed will be used synonymously with
both processes, unless otherwise noted. Desorption refers to
the process of removing a sorbed material from the solid on
which it is sorbed. Leaching refers to the removal or extraction
of soluble components of a material (i.e., casing material) by a
solvent (Sax and Lewis, 1987).
Casing material in contact with a liquid has the potential to allow
either leaching and/or sorption. Factors influencing sorption of
organics and metals are discussed by Jones and Miller (1988)
and Massee et al., (1981), respectively. These factors include:
1. The surface area of the casing. The greater the ratio of
casing material surface area to the volume of adsorbate the
greater the sorption potential.
2. Nature of the analyte (chemical form and concentration).
3. Characteristics of the solution. This includes factors such
as pH, dissolved material (e.g., salinity, hardness)
complexing agents, dissolved gasses (especially oxygen'
which may influence the oxidation state), suspended matter
(competitor in the sorption process), and microorganisms
(e.g., trace element take-up by algae).
4. Nature of the casing material (adsorbent). This includes
factors such as the chemical and physical properties of the
casing material.
5. External factors. These factors include temperature, con-
tact time, access of light, and occurrence of agitation.
According to Barcelona et al., (1988) considerations for select-
ing casing material should also include the subsurface aeo-
chemistry and the nature and concentration of the contaminants
of interest. They also state that strength, durability, and inert-
ness of the casing material should be balanced with cost
considerations. Ford (1979) summarized factors related to the
analyte that can affect adsorption (Table 1).
TABLE 1. FACTORS AFFECTING ADSORPTION
1. An increasing solubility of the solute in the liquid carrier decreases its
adsorbability.
2. Branched chains are usually more adsorbable than straight chains. An
increasing length of the chain decreases solubility.
3. Substituent groups affect adsorbability.
Substituent Group
Hydroxyl
Amino
Carbonyl
Double Bonds
Halogens
Sulfonic
Nitro
Aromatic Rings
Nature of Influence
Generally reduces absorbability; extent of decrease
depends on structure of host molecule.
Effect similar to that of hydroxyl but somewhat
greater. Many amino acids are not adsorbed to any
appreciable extent.
Effect varies according to host molecule; glyoxylic
are more adsorbable than acetic but similar increase
does not occur when introduced into higher fatty
acids.
Variable effect as with carbonyl.
Variable effect.
Often increases adsorbability.
Greatly increases adsorbability.
4. Generally, strong ionized solutions are not as adsorbable as weakly
ionized ones; i.e., undissociaJed molecules are in general preferentially
adsorbed.
5. The amount of hydrolytic adsorption depends on the ability of the
hydrolysis to form an adsorbable acid or base.
6. Unless the screening action of the adsorbent pores intervene, large
molecules are more sorbable than small molecules of similar chemical
nature. This is attributed to more solute-adsorbent chemical bonds
being formed, making desorption more difficult,
7. Molecules with low polarity are more sorbable than highly polar ones.
(Source: Ford, 1979)
^ ^0P*en^er9 (1981) conducted an investigation to
«f!kLm'ne a ®orrelat,on between diffusivity and size and shap*
^molecu,es- Their study indicated that as the
"spherical" penetrant molecules increased, the
!Creasec,expo'1emia,|y- Another finding of the study
as mat flattened or elongated penetrant molecules such as fl"
oi^i1es , 9reater diffusivities than spherical molecules
s milar volume or molecular weight. This may indicate the*
eongated molecules can move along their long axis wh®11
diffusing through a polymer.
("1985) used a mathematical model ^
p edict the absorption of organic compounds by the differ0f1
2
-------
polymer materials. Curves based on their model were fit to
experimental data and showed reasonable agreement. This
agreement supports their concept that uptake is the result of
absorption. They also determined that no relationship was
found between the order of absorption and readily available
parameters such as aqueous solubility or octanol/water parti-
tioning coefficient. They concluded that predicting the amount
of absorption for a particular organic compound was not pos-
sible at that time.
Gillham and O'Hannesin (1990) attempted to predict the rate of
uptake of benzene, toluene, ethylbenzene, and p-, m-, and o-
xylene onto samples SS316, PTFE, rigid PVC, flexible PVC,
polyvinylidene fluoride (PVDF), flexible PE, and FRE employing
the same model as that used by Reynolds and Gillham (1985).
Their results showed the diffusion model data fitted their experi-
mental data quite well, suggesting the sorption mechanism was
absorption into the polymer materials agreeing with the results
of Reynolds and Gillham (1985). They also determined, that for
the organic compounds used in this study, the rate of uptake
increased with increasing hydrophobicity of the organic com-
pound and varied with the physical characteristics of the poly-
mer casing material.
types of casing materials
A variety of materials may be used for casing and screening
ground-water monitoring wells. These materials include glass
and metallic and synthetic materials. Rigid glass has the least
potential for affecting a sample and is the material of choice for
sampling organics (Pettyjohn et al., 1981). However, because
the use of glass as a casing material is impractical for field
applications because of its brittleness, it will not be further
considered in this report.. Instead, this report will focus on the
metallic and synthetic materials most commonly used for
monitoring well construction.
Metals
Metals are often chosen as casing materials because of their
strength. Metals used for casing include SS, carbon steel,
Galvanized steel, cast iron, aluminum, and copper. The various
metals used for well casings may react differently to different
compounds. Reynolds et al., (1990) conducted a study using
SS, aluminum, and galvanized steel to determine their potential
to cause problems in samples collected for analysis for haloge-
nated hydrocarbons. The metals were subjected to aqueous
solutions of 1,1,1-trichloroethane (1,1,1-TCA), 1,1,2,2-
tetrachloroethane (1,1,2,2,-TET), hexachloroethane (HCE),
oromoform (BRO), and tetrachloroethylene (PCE) for perils
UP to 5 weeks. The study indicated that, of the metals used, SS
Was the least reactive followed by aluminum and galvanized
steel. Stainless steel caused a 70 percent reduction of BRO and
HCE after 5 weeks. Aluminum caused over a 90 percent
deduction for all but one of the compounds while galvanized steel
showed over a 99 percent reduction for all of the compounds.
Many investigations have shown that errors may be introduced
into the water sample as a result of using metal casings. For
'"stance, Marsh and Lloyd (1980) determined steel-cased wells
modified the chemistry of the formation water. They state that
trace element concentrations of the ground water collected from
the wells were not representative of the aquifer conditions and
did not recommend the use of steel casing for constructing
monitoring wells. They suspected that reactions between the
ground water and the steel casing raise the pH of the water
which causes the release of metal ions into solution. Pettyjohn
et al., (1981) found metals strongly adsorb organic compounds.
For example, they claim that DDT is strongly adsorbed even by
SS. Hunkin et al., (1984) maintain that steel-cased wells are
known to add anomalously high iron and alloy levels as well as
byproducts of bacterial growth and corrosion to a sample.
Houghton and Berger (1984) discovered that samples from
steel-cased wells were enriched in cadmium (Cd), chromium
(Cr), copper (Cu), iron, manganese, and zinc (Zn) relative to
samples obtained from plastic-cased wells.
Stainless steel is one type of metal used for casing and that
appears to have a high resistance to corrosion. In fact, the U.S.
EPA (1987) states that SS is the most chemically resistant of the
ferrous materials. Two types of SS extensively used for ground-
water monitoring are stainless steel 304 (SS304) and stainless
steel 316 (SS316). These are classified as austenitic type SS
and contain approximately 18 percent chromium and 8 percent
nickel. The chemical composition of SS304 and SS316 is
identical with the exception being SS316 which contains 2-3
percent molybdenum. Brainard-Kilman (1990) indicate SS316
has improved resistance to sulfuric and saline conditions and
better resistance to stress-corrosion.
The corrosion resistance of SS is due to a passive oxide layer
which forms on the surface in oxidizing environments. This
protective layer is only a few molecules thick. It recovers quickly
even if removed by abrasion (Fletcher 1990). However, several
investigators note that SS is still susceptible to corrosion. Under
corrosive conditions, SS may release iron, chromium, or nickel
(Barcelona et al., 1988). Hewitt (1989a) found in a laboratory
study that samples of SS316 and SS304 were susceptible to
oxidation at locations near cuts and welds. When these cuts and
welds are immersed in ground water, this surface oxidation
provides active sites for sorption and also releases impurities
and major constituents. SS may be sensitive to the chloride ion,
which can cause pitting corrosion, especially over long term
exposures under acidic conditions (U.S. EPA, 1987).
Parker et al., (1989) evaluated samples of SS304 and SS316 for
their potential to affect aqueous solutions of 10 organic com-
pounds. The 10 organics used in the study were RDX,
trinitrobenzene (TNB), c-1,2-DCE, t-1,2-DCE, m-nitrotoluene
(MNT), TCE, MCB, o-dichlorobenzene (ODCB),
p-dichlorobenzene (PDCB), and m-dichlorobenzene (MDCB) at
concentrations of 2 mg/L Their study indicated the SS well
casings did not affect the concentration of any of the anafytes in
solution.
Synthetic Materials
Synthetic materials used for casing evaluation include PTFE,
PVC, polypropylene (PP), polyethylene (PE), nylon, fiberglass
reinforced epoxy (FRE), and acrylontoile butadiene styrene
(ABS). The two most commonly used synthetic casing materials
are PVC and PTFE. Very little information regarding the
suitability of FRE as a casing material is presently available in
3
-------
the literature; however, a 3-week dweil-time study conducted by
Cowgill (1988) indicated that FTFE revealed no detectable
quantities of the substances used in its manufacture. Hewitt
{1989a and 1989b) determined that PTFE was the material of
choice for sampling inorganic compounds whereas, Barcelona
(1985) recommends PTFE for most ail monitoring applications.
PTFE is a man-made material composed of very long chains of
linked fluorocarbon units. PTFE is considered as athermoplas-
tic with unique properties. It is very inert chemically and no
substance has been found that will dissolve this polymer (The
Merck Co. Inc. 1984). The Merck Co. Inc. (1984) reports that
nothing sticks to this polymer. This antistick property may
prevent grouts from adhering to PTFE casing and prevent the
development of an effective seal around a PTFE casing. PTFE
aiso has a very wide useful temperature range, -100° to
+460° F; however, for most ground-water monitoring applica-
tions these extremes of temperature would rarely be
encountered.
PTFE has a low modulus of elasticity making the screened
portion PTFE casing prone to slot compression under the weight
of the well casing above. PTFE is also very flexible and the
casing sometimes has the tendency to become "crooked" or
"snake" especially in deep boreholes. Special procedures are
then required to install the casing. Morrison (1986) and Dablow
et al., (1988) discuss different techniques used to overcome
installation problems inherent to PTFE wells. PTFE also has the
tendency to stretch thus, making PTFE cased wells susceptible
to leaks around threaded joints.
PVC casing is an attractive alternative to PTFE and SS because
it is inexpensive, durable, lightweight, has better modulus and
strength properties than PTFE, and is easy to install. However,
these characteristics alone do not justify its use as a monitoring
well casing material. The casing material must not react
significantly with the surrounding ground water, leach, sorb, or
desorb any substances that might introduce error into the
sample. Many studies have been conducted comparing PVC to
other casing materials to determine its suitability for use in
monitoring wells.
Various compounds are added to the basic PVC polymer during
the manufacturing process of rigid PVC. These compounds
include thermal stabilizers, lubricants, fungicides, fillers, and
pigments (Boettner et al., 1981; Packham, 1971). It is pre-
sumed that the additional compounds have the potential to leach
into the ground water. Tin, found in some thermal stabilizers, is
one of the compounds suspected of leaching from PVC.
Boettner et al., (1981) found that as much as 35 ppb dimethyltin
could be leached from PVC in a 24-hour period. Other com-
pounds used as thermal stabilizers, and potential sources of
contaminants, are calcium, Zn, and antimony.
Another compound suspected of leaching from PVC casing is
residual vinyl chloride monomer (RVCM). According to Jones
and Miller (1988), 1-inch diameter Schedule 40 PVC pipe
containing 10-ppm RVCM leaches undetectable quantities (at
the 2.0-ppb sensitivity level) of vinyl chloride into stagnant water
retained in the pipe. They also report that 98 percent of the PVC
casing currently manufactured in North America contains less
than 10-ppm RVCM and most casing contains less than 1 ppm
RVCM. This implies that a 1-inch diameter pipe should leach
2.0-ppb or less RVCM. The amount of RVCM leached would
aiso decrease as the casing diameter increased because of the
lower specific surface. Specific surface (R) is defined as the
ratio of the surface area of the casing material in contact with the
solution, to the volume of the solution. Thus, as casing diameter
increases, the specific area decreases.
The NSF (1989) has established maximum permissible levels
(MPL) for many chemical substances used in the manufacturing
of PVC casing (Table 2). These levels are for substances found
in low pH extractant water following extraction procedures
described by the NSF (1989). Sara (1986) recommends the use
of NSF-tested and approved PVC formulations to reduce the
possibility of leaching RVCM, fillers, stabilizers, and plasticizers.
TABLE 2. MAXIMUM PERMISSIBLE LEVELS FOR CHEMICAL
SUBSTANCES
Substances
MPLmg/L
Action levels mg/L
Antimony
0.05

Arsenic
0.050

Cadmium
0.005

Copper
1.3

Lead
0.020

Mercury
0.002

Phenolic Substances

0.05'
Tin
0.05
Total Organic Carbon

5.01
Total Trihalomethanes
0.10
Residual Vinyl Chloride Monomer*
3.2
2.02
* In the finished product ppm (mg/kg).
' This is an action level. If the level is exceeded, further review and/or
focfinn chall ***. -'-J--*'A *'
> initiated to identify the specific substance(s), and
acceptance or rejection shall be based on the level of specific
substances in the water.
inventory and tested to
monitor for conformance to the MPL.
(Source: NSF Standard Number u)
Common practice was to use cleaner-primers and solvent
cements to join PVC casing sections used in monitoring wells-
cements used for joining casing sections dissolve some of th®
polymer and "weld" the casing sections together. Past studies
snowed a correlation between certain organic compounds
round in ground-water samples and the use of PVC solver"
«fT?tQL^eJ?ner et al- 1981: Pettyjohn et al., 1981; Sosebee
etai.,1983; CurranandTomson, 1983). Sosebeeetal., (1983)
'9^ levels of tetrahydrofuran, methylethylketone.
onH jSow^lke*0ne'80(1 cyclohexanone, the major constitu*
PV9 Punier and adhesive, in water surrounding °f'
m qqo\ casing joints months after installation. Sosebee at al-
L_®7 determined that besides contaminating the ground"
water sample these contaminants have the potential to m®8
-------
other compounds found in the ground water during laboratory
analysis. Boettner et al., (1981) found, in an experiment in which
solvent cement was used for joining PVC casing,
methylethylketone, tetrahydrofuran, and cyclohexanone leach-
ing into water supplies after more than 2 weeks of testing.
Houghton and Berger (1984) conducted a study to determine the
effects of well casing composition and sampling method on
water-sample quality. Three wells were drilled on 20-ft centers
to a depth of 60 feet and cased with PVC, ABS, and steel.
Samples collected from the wells indicated ABS-cased wells
were enriched in dissolved organic carbon by 67 percent and in
total organic carbon (TOC) by 44 percent relative to samples from
the steel-cased well. The PVC-cased well was enriched in
dissolved organic carbon and TOC by approximately 10 percent
relative to the steel-cased well. The high TOC concentrations
found in the ABS and PVC casings are suspected to have been
derived from the cement used to connect the casing sections.
Other compounds suspected of leaching from PVC and into
ground water are chloroform (CHCI) and carbon tetrachloride
(CCL). Desrosiers and Dunnigan (1983) determined that PVC
pipe did not leach CHCI3 or CCL, into deionized, demineralized,
organic-free water, ortap water in the absence of solvent cement
even after a 2-week dwell time.
PVC primers and adhesives should not be used for joining PVC
monitoring well casing sections. The recommended means for
joining PVC casing is to use flush-joint threaded pipe casing.
Foster (1989) provides a review of ASTM guideline F480-88A
which describes in detail the standard PVC flush-joint thread.
Junk et al., (1974) passed "organic free" water through PE, PP,
latex, and PVC tubings, and a plastic garden hose. They found
o-creosol, naphthalene, butyloctylfumarate, and butyl-
chloroacetate leaching from the PVC tubing. These contami-
nants are related to plasticizers which are added to PVC during
the manufacturing process to make it more flexible. Rigid PVC
well casing contains a much smaller quantity of plasticizer and
should be less prone to leaching contaminants (Jones and Miller,
1988).
leaching and sorption studies
Many studies have been undertaken to determine the interaction
of different casing materials with volatile organic compounds
(VOCs) and trace metals. Much of the research has been aimed
at determining whether PVC can be used as a substitute for more
expensive materials such as PTFE, FRE, and SS. A review of the
literature investigating the potential effects of assorted well
casing materials on ground-water samples is presented below.
Organic Studies
Lawrence and Tosine (1976) found that PVC was effective for
adsorbing polychlorinated biphenyls (PCB) from aqueous sew-
age solutions. They reported that the low solubility and hydro-
Phobic nature of the PCBs makes them relatively easy to adsorb
from aqueous solution. Parker et al., (1989) suggest the PVC
Appears to be effective only in sorbing PCBs at concentrations
c'ose to their solubility limits.
Pettyjohn et al., (1981) discuss materials used for sampling
organic compounds. They provide a list of preferred materials for
use in sampling organic compounds in water. Their choice in
order of preference is glass, PTFE, SS, PP, polyethylene, other
plastics and metals, and rubber. They do not indicate whether
the materials in the list were sections of rigid or flexible tubing or
what testing procedures were followed. They note that experi-
mental data on the sorption and desorbtion potential of casing
materials using varied organic compounds were not available.
Miller (1982) conducted a laboratory study in which one of the
Objectives was to quantify adsorption of selected organic pollut-
ants on Schedule 40 PVC 1120, low density PE, and PP well
casing materials. These materials were exposed to six organic
pollutants and monitored for adsorption over a 6-week period.
The VOCs used, along with their initial concentrations, were BRO
(4 ppb), PCE (2 ppb), trichloroethylene (TCE) (3 ppb),
trichlorofluoromethane (2 ppb), 1,1,1-TCA (2 ppb), and 1,1,2-
trichloroethane (14 ppb). "Hie results showed that PVC adsorbed
only PCE. The PVC adsorbed approximately 25 to 50 percent of
the PCE present. The PP and PE samples adsorbed all six of the
organics in amounts ranging from 25 to 100 percent of the
amount present.
Curran and Tomson (1983) compared the sorption potential of
PTFE, PE, PP, rigid PVC (glued and unglued), and Tygon
(flexible PVC). The procedures used in this investigation con-
sisted of pumping 20 L of organic-free water with a 0.5-ppb
naphthalene spike through each tubing at a rate of 30 mUmin.
The tests showed that 80 to 100 percent of the naphthalene was
recovered from the water for all materials except Tygon tubing.
Tygon tubing sorbed over 50 percent of the naphthalene. PTFE
showed the least contaminant leaching of the synthetic materials
tested. They concluded that PVC can be used as a substitute for
PTFE in monitoring wells if the casing is properly washed and
rinsed with room temperature water before installation. They
also conclude that PE and PP could suitably be used as well
casings.
Barcelona et al., (1985) presented a ranking of the preferred rigid
materials based on a review of manufacturers' literature and a
poll of the scientific community. The list presented by Barcelona
et al., (19&5) recommended the following casing materials in
order of decreasing preference: PTFE, SS316, SS304, PVC,
galvanized steel, and low carbon steel. Table 3 presents
recommended casing materials tabulated in Barcelona et al.,
(1985) along with specific monitoring situations.
Reynolds and Gillham (1985) conducted a laboratory study to
determine the effects of five halogenated compounds on six
polymer materials. The five compounds used in this study were
1,1,1-TCA, 1,1,2,2-TET, HCE, BRO, and PCE. The polymer
materials studied were PVC rod, PTFE tubing, nylon plate, low
density PP tubing, low density PE tubing, and latex rubbertubing.
The authors evaluated nylon plate because nylon mesh is often
used as a filter material around screened portions of wells. Latex
rubber tubing was evaluated as a material that represented
maximum absorption. The materials were tested under static
conditions to simulate water standing in the borehole. Measure-
ments were made over contact times that ran from 5 minutes to
5 weeks.
5
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TABLE 3. RECOMMENDATIONS FOR RIGID MATERIALS IN
SAMPUNG APPLICATIONS
(In decreasing order of preference)
Material
PTFE (Teflon®)
Recommendations
Recommended for most monitoring situations
with detailed organic analytical needs, particularly
Stainless Steel 316
(flush threaded)
hydrogeologic conditions. Virtually an ideal
material for corrosive situations where inorganic
contaminants are of interest.
Recommended for most monitoring (flush
threaded) situations with detailed organic
analytical needs, particularly for aggressive,
organic leachate impacted by hydrogeologic
conditions.
Stainless Steel 304 May be prone to slow pitting corrosion in contact
PVC (flush threaded)
other noncemented
connections, only NSF-
approved materials
for casing or potable
water applications.
Low Carbon Steel
Galvanized Steel
Carbon Steel
Results of the study are presented in Table 4. The results show
that PVC absorbed four of the five compounds; however, the
rate of absorption was relatively slow (periods of days to weeks).
Given this slow absorption rate, they do not consider there would
be significant absorption by PVC if wells were purged and
sampled the same day. The one organic compound that was not
absorbed significantly by the PVC during the 5-week test period
was 1,1,1-TCA. The loss of BRO to PVC in this study was
approximately 43 percent after 6 weeks; whereas, Miller (1982),
in a similar experiment, indicated no losses from solution over
the same time period.
TABLE 4. TIME AT WHICH ABSORPTION REDUCED THE RELATIVE
CONCENTRATION IN SOLUTION TO 0.9
solutions. Corrosion products limited mainly to
Fe and possibly Cr and Ni.
Recommended for limited monitoring situations
where inorganic contaminants are of interest and
it is known that aggressive organic leachate
mixtures will not be contacted. Cemented
installations have caused documented
interferences. The potential for interaction and
interferences from PVC well casing in contact
with aggressive aqueous organic mixtures is
difficult to predict. PVC is not recommended for
detailed organic analytical schemes.
Recommended for monitoring inorganic
contaminants in corrosive, acidic inorganic
situations. May release Sn or Sb compounds
from the original heat stabilizers in the
formulation after long exposure.
May be superior to PVC for exposures to
aggressive aqueous organic mixtures. These
materials must be very carefully cleaned to
remove oily manufacturing residues. Corrosion is
likely in high dissolved solids acidic environment,
particularly when sulfides are present. Products
of corrosion are mainly Fe and Mn, except for
galvanized steel which may release Zn and Cd.
Weathered steel surfaces present very active
sites for trace organic and inorganic chemical
PVC
1,1,1-TCA
1,1,2,2-TET
BRO
HCE
PCE

>5 weeks
-2 weeks
-3 days
-1 day
-1 day
PTFE
BRO
1,1,2,2-TET
1,1,1-TCA
HCE
PCE

>5 weeks
-2 weeks
-1 day
-1 day
<5 minutes
Nylon
1,1,1-TCA
1,1,2,2-TET
BRO
PCE
HCE

-6 hours
-1 hour
-30 minutes
-30 minutes
<5 minutes
PP
1,1,2,2-TET
BRO
1,1,1-TCA
HCE
PCE

-4 hours
-1 hour
-1 hour
<5 minutes
<5 minutes
PE
1,1,2,2-TET
BRO
1,1,1-TCA
HCE
PCE

-15 minutes
<5 minutes
<5 minutes
<5 minutes
<5 minutes
Latex
1,1,2,2-TET
1,1,1-TCA
BRO
PCE
HCE
Rubber <5 minutes
<5 minutes
<5 minutes
<5 minutes
<5 minutes
(Source: Reynolds and Gillham, 1965)
PTFE showed absorption of four of the five compounds tested.
There was no significant absorption of BRO over the 5-week test
period. It is noted that approximately 50 percent of the original
concentration of PCE was absorbed within an 8-hour period.
The concentration of this compound may be affected even when
the time between purging and sampling is short.
The other casing materials demonstrated significant absorption
losses within minutes to a few hours after exposure to the
organic compounds. The use of nylon, latex rubber, PP, and PE
as a well casing material will cause a significant reduction in the
concentration of the organic compounds even when the time
between purging and sampling is short. They state that agree-
ment between the model study and experimental results support
the concept that absorption of the organic compounds by the
polymers occur by sorption/dissolution of the compounds into
the polymer surface followed by diffusion into the polymer
matrix.
(Source: Barcelona et a/., 1985)
6
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Parker and Jenkins (1986) conducted a laboratory study to
determine if PVC casing was a suitable material for monitoring
low levels of the explosives 2,4,6-trinitrotoluene (TNT),
hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), octahydro-
1,3,5,7-tetranitro 1,3,5,7-tetrzocine (HMX), and 2,4-
dinitrotoluene (DNT). Samples of PVC casing were placed in
glass jars containing an aqueous solution of TNT, RDX, HMX,
and DNT. After 80 days, the solution was tested to determine the
concentration of TNT, RDX, HMX, and DNT left in solution. After
the 80 days, the solutions containing RDX, HMX, and DNT
showed little loss, whereas TNT showed a significant loss. PVC
casing was tested under sterile and nonsterile conditions in a 25-
day experiment to determine whether microbial degradation or
sorption by PVC was the cause for losses of TNT, RDX, HMX,
and DNT. Results indicated that the loss of TNT in the test was
caused by microbial activity rather than to adsorption. The
increased microbial activity may be caused by bacteria initially
present on the unsterilized PVC casing, increased surface area
for colonization provided by the PVC surface, leaching of
nutrients from the casing increasing the growth of bacteria, and
the rate of biodegradation.
Parker and Jenkins (1986) do not consider PVC casing to
significantly affect ground-water samples when monitoring for
TNT, RDX, DNT, and HMX if the time between purging of the well
and sampling is short. They concluded PVC is an acceptable
casing material for ground-water monitoring of TNT, RDX, DNT,
and HMX.
Sykes et al., (1986) performed a laboratory study to determine
if there was a significant difference in the sorption potential
between PVC, PTFE, and SS316 when exposed to methylene
chloride (dichloromethane or DCM), 1,2-dichloroethane (1,2-
DCA), trans-1,2-dichloroethylene (t-1,2-DCE), toluene, and
chlorobenzene (MCB). Samples of the various well casing
materials were placed in jars containing aqueous solutions of
the solvents at concentrations of approximately 100 ppb. The
concentration of each solvent was determined after 24 hours
and again after 7 days. The study concluded that there were no
statistically different chemical changes in the solutions exposed
to PVC, PTFE, and SS316 casing. Thus, it could be presumed
that PVC, PTFE, or SS316 are suitable casing materials for
monitoring DCM, 1,2-DCA, t-1,2-DCE, toluene, and MCB when
the period between well purging and sampling is less than 24
hours.
Barcelona and Helfrich (1986) conducted a field study at two
landfills to determine the effects of different casing materials on
sample quality. Wells were constructed upgradient and
downgradient of each of the two landfill sites. The wells at
Landfill 1 were constructed of PTFE, PVC, and SS304; whereas,
the wells at Landfill 2 were constructed of PVC and SS.
They observed that the downgradient SS and PTFE wells at
Landfill 1 showed higher levels of TOC than did the PVC wells.
The upgradient wells at Landfill 1 showed no significant differ-
ence among casing material type. TOC sampling at Landfill 2
showed similar results; however, no significant differences
among material types were determined either upgradient or
downgradient of the landfill.
Levels of 1,1-dichloroethane (1,1-DCA) and cis-1,2-
dichloroethylene (c-1,2-DCE) were significantly higher for the
downgradient SS wells than for PTFE and PVC cased wells at
Landfill 1. They suspect that PTFE and PVC tend to have a
greater affinity for these organic compounds than does SS.
At Landfill 2 they noted greater levels of 1,1-DCA and total
volatile halocarbons in the PVC wells than in the SS wells. They
hypothesize that the higher levels of the organic compounds
found in the water samples from the PVC cased well may be
caused by the sorptive and leaching properties of PVC which
tend to maintain a higher background level of organic com-
pounds in the ground water relative to SS. They did not suspect
the SS and PVC wells at Landfill 2 are intercepting ground water
of different quality since the wells are approximately 4 feet apart.
The authors conclude that well casing materials exert signifi-
cant, though unpredictable effects on TOC and specific VOC
determinations. Parker et al., (1989) suspect that a larger
statistical base is needed before such conclusions can be
drawn. Parker et al., (1989) also suggest the possibility that
differences in well construction methods may have had an effect
on the quality of these water samples.
Gossett and Hegg (1987) conducted a laboratory test to deter-
mine the effects of using a PVC bailer, a PTFE bailer, and an
ISCO Model 2600 portable pump on the recovery of CHCI,,
benzene, and 1,2-DCA. The effect on recovery of VOCs was
studied by varying the lift height and the casing material. The
casing materials consisted of either PVC or SS. In their
conclusion they state that either PVC or SS would be suitable for
collecting VOC samples.
Parker et al., (1989) performed a laboratory study to compare
the performance of PVC, SS304, SS316, and PTFE subjected
to aqueous solutions of RDX, trinitrobenzene (TNB),
c-1,2-DCE, t-1,2-DCE, m-nitrotoluene (MNT), TCE, MCB,
o-dichlorobenzene (ODCB), p-dichlorobenzene (PDCB), and
m-dichlorobenzene (MDCB) at concentrations of 2 mg/L. A
biocide was added to the samples to eliminate possible losses
due to biodegradation.
Prior to the experiment, they conducted a test to determine if the
casing materials were capable of leaching any compounds into
water. Samples of casing material were placed in vials contain-
ing well water and allowed to stand for 1 week. No evidence of
materials leaching from any of the casing materials was noted.
Casing samples were placed in sample jars containing an
aqueous solution of the organic compounds and sampled ini-
tially and at intervals between 1 hour and 6 weeks. Table 5
presents results after a 1 -hour, 24-hour, and 6-week dwell time.
The test results indicated that after 6 weeks PTFE had sorbed
significant amounts of all the compounds with the exception of
RDX and TNB. In the same time period, PVC showed significant
sorption of TCE, MCB, ODCB, PDCB and MDCB. In each one
of the cases where the PVC and PTFE both sorbed significant
amounts of analytes, PTFE always had the greatest sorption
rate. After 6 weeks, the SS samples exhibited no significant
sorption of the tested compounds.
At the 24-hour mark, PTFE and PVC had experienced signifi-
cant sorption of all the compounds with the exception of RDX,
TNB, and MNT. For the compounds sorbed by PTFE and PVC,
PTFE had the higher rate of uptake with the exception of c-1,2-
DCE. SS showed no significant sorption of any of the com-
7
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TABLE 5. NORMALIZED* CONCENTRATION OF ANALYTES FOR
FOUR WELL CASINGS WITH TIME
Analyte
Treatment
1 hour
24 hours
6 weeks
RDX
PTFE
1.03
1.00
0.99

PVC
1.01
0.98
1.00

SS304
0.99
1.01
0.98

SS316
1.01
1.01
1.00
TNB
PTFE
1.01
1.00
1.01

PVC
1.01
0.98
1.02

SS304
0.99
1.00
1.00

SS316
1.02
1.01
1.02
c-1,2-DCE
PTFE
1.01
0.96t
0.79t
PVC
1.00
0.95f
0.90

SS304
0.97
1.00
0.98

SS316
0.95
1.00
0.99
t-1,2-DCE
PTFE
1.00
0.88t
0.56t
PVC
1.00
0.931*
0.83

SS304
0.95t
1.00
1.00

SS316
1.00
1.00
1.00
MNT
PTFE
1.03
0.99
0.90t

PVC
1.02
0.98
0.94

SS304
1.00
1.01
1.07

SS316
1.02
1.02
0.99
TCE
PTFE
1.00
0.85f
0.40t

PVC
1.01
0.94f
0.88f

SS304
0.96
1.01
0.99

SS316
1.00
1.00
1.00
MCB
PTFE
1.01
0.90t
0.511

PVC
1.01
0.95f
. 0.86f

SS304
0.98
1.00
0.99

SS316
0.99
1.01
0.99
ODCB
PTFE
1.01
0.88f
0.43f

PVC
1.02
0.94f
0.86t

SS304
0.98
1.00
1.00

SS316
1.01
1.01
1.00
PDCB
PTFE
0.92f
0.77t
0.26t

PVC
0.95
0.92t
0.80t

SS304
0.911
1.00
1.02

SS316
0.94
1.00
1.02
MDCB
PTFE
1.00
0.78t
0.26f

PVC
1.02
0.92f
o.eot

SS304
0.99
1.00
1.02

SS316
1.03
1.00
1.01
* The values given here are determined by dividing the mean
concentration of a given analyte at a given time and for a particular well
casing by the mean concentration (for the same analyte) of the control
simples taken at the same time.
f Values significantly different from control values.
(Source: Parker etal., 1989)
pounds tested. It appears that PTFE cased wells will introduce
a greater bias into ground-water samples than those cased witn
PVC if the time between sampling and purging is 24 hours.
They also conducted a desorption experiment on the samples
that had sorbed organics for 6 weeks. After 3 days of testing .the
PVC and PTFE samples showed desorption of analytes sorted
in the previous experiment. The desorption study showed that
PTFE, in general, showed a greater loss of analytes than PVC.
Jones and Miller (1988) conducted laboratory experiments to
evaluate the adsorption and leaching potential of Schedule 40
PVC (PVC-40), Schedule 80 PVC (PVC-80), ABS, SS, Tefion-
PFA, Teflon-FEP, PTFE, and Kynar-PVDF. Organic com-
pounds used in this experiment were 2,4,6-trichlorophenoi
(2,4,6-TCP), 4-nitrophenol, diethyl pthalate, acenaphthene,
naphthalene, MDCB, 1,2,4-trichlorobenzene, a no
hexachlorobenzene. Samples of casing material were placeo
into glass vials each containing an organic compound having an
approximate initial concentration of 250 ppb.
In their first experiment, the organic compounds were mixed with
neutral pH ground water. The batches were sampled immedi-
ately and then at intervals of 1-, 3-, and 6-weeks. The result
showed that there was no appreciable change in adsorption o
the compounds after 1 week except for 2,4,6-TCP, which totally
adsorbed after 3 weeks. The results also indicate that PTr-c
might be less likely to adsorb these compounds. Jones an
Miller (1988) also point outthat at the concentrations used in this
study, PTFE, PVC-40, and PVC-80 exhibited very little differ-
ence in the amounts of adsorption.
In their second experiment, Jones and Miller (1988) attempted
to determine the amount of the adsorbed compounds that woui
be released back into uncontaminated ground water after a
week exposure time. After a 2-week period, very little release
organic contaminants was observed. They state that only ze
to trace amounts of the sorbed contaminants were desorbedin
the noncontaminated ground water. Only PVC-80 and Teflo
PFA desorbed naphthalene.
They repeated their adsorption and leaching experiments usijjfl
polluted ground water with a pH of 3.0. The adsorption ®XP®
ment showed that, with the exception of ABS casing, the casinw
materials showed less adsorption at the contaminated
level than at the noncontaminated neutral pH level.
possible explanation is there could be stronger binding a
more preferential complexing of the experimental pollutants w
other pollutants in the contaminated ground water. Anotn >
more likely explanation, is that there is a relationship bewe
the extent of adsorption, pH, and pK, with a maximum adaoK
tion occurring when the pH is approximately equal to pK.
explain that as the pH decreases, the hydrogen ion
tion increases and the adsorption tends to decrease, sugge®^,
a replacement of the adsorbed compound by the more preterm
tially adsorbed hydrogen ions.
Jones and Miller (1988) concluded there is no clear advanj^
to the use of one particular well casing material over theotn^
for the organics used in the study. Well purging
sampling device selection and composition, and sample s'K>,
are probably o* greater influence to sample integrity and tw^
sentativeness thian well casing material selection. They
8
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the amount of adsorption generally correlates with the solubility
of the chemical independent of the well casing material.
Gillham and O'Hannesin (1990) conducted a laboratory study to
investigate the sorption of six monoaromatic hydrocarbons
onto/into seven casing materials. The six organic compounds
used were benzene, toluene, ethylbenzene, and p-, m-, and o-
xylene. The seven casing materials used in the evaluation were
SS316, PTFE, rigid PVC, flexible PVC, polyvinylidene fluoride
(PVDF), flexible PE, and FRE. The materials were placed in
vials containing an aqueous solution of all six organic materials.
Concentrations of the organics in the solution ranged between
1.0 and 1.4 mg/L. Sodium azide (0.05 percent), a biocide, was
added to the solution to prevent biodegradation of the organics.
The solutions were sampled 14 times from 5 minutes to 8 weeks.
Results of the study are presented in Table 6 and indicate that
SS is the most favorable casing material for sampling organics.
Stainless steel showed no significant uptake after an 8-week
exposure period; whereas, all the polymer materials adsorbed
all the organic compounds to some degree. The order of
magnitude of adsorption for the .various polymer materials
tested was flexible PVC > PE > PTFE > PVDF > FRE > rigid PVC
(from greatest to least sorption). Flexible tubing materials
showed substantial uptake after 5 minutes of exposure. Rigid
PVC showed the lowest rate of uptake of the polymer materials.
TABLE 6. TIME INTERVAL WITHIN WHICH THE CONCENTRATION
PHASE FOR THE COMPOUND AND CASING MATERIAL BECAME
SIGNIFICANTLY DIFFERENT FROM 1.0
Time, hours
Ethyl-
Material Benzene Toluene benzene m-Xylene o-Xylene p-Xylene
SS316 >1344

PVC (rigid) 48-96
24-48
12-24
12-24
12-24
12-24
FRE 24-48
3-6
0.1-1.0
3-6
3-6
3-6
PVDF 24 - 48
3-6
1-3
1 -3
0.1-1.0
1-3
PTFE 24-48
3-6
1 -3
3-6
6-12
1 -3
PE 0-0.1
0-0.1
0-0.1
0-0.1
0-0.1
0-0.1
PVC (flexible) 0-0.1
0-0.1
0-0.1
0-0.1
0-0.1
0-0.1
(Source: Gillham and O'Hannesin, 1990)
Gillham and O'Hannesin (1990) conclude all of the polymer
materials tested, except flexible PVC and PE, are suitable
casing materials in monitoring wells. This is based on selection
of an appropriate casing diameter and an appropriate interval
between purging and sampling. They state rigid PVC is the most
favorable polymer material for casing in monitoring wells.
Reynolds et al., (1990) conducted laboratory tests to evaluate
the effects of five halogenated hydrocarbons on several casing
Materials. The halogenated hydrocarbons and casing materials
used in the experiment were identical to those used by Reynolds
and Gillham (1985) with the addition of glass, SS316, aluminum,
and galvanized sheet metal to the casing materials.
The results indicated borosilicate glass was the least likely of the
10 materials to affect the samples. The results also showed that
all of the metals had the potential to sort compounds from
solution. The order of the compound sorption rate for the metals
was galvanized steel > aluminum > SS (greatest to least
sorption).
Results of the sorption experiments indicated rigid PVC was
preferable to PTFE for sampling low concentrations of haloge-
nated hydrocarbons. The compound sorption rates, from great-
est to least sorption, are latex > low density PE > PP > nylon >
PTFE > rigid PVC. The rates of compound loss, from greatest
to least loss, are PCE >HCE> 1,1,1 -TCA > BRO >1,1,2,2-TET.
It should be noted the inequalities shown above are not neces-
sarily significant. For example, the rates between PTFE and
rigid PVC are not significant and the same is true for nylon and
PP. Their study showed flexible polymer tubing is likely to have
greater sorption rates than rigid polymers which is in agreement
with Barcelona et al., (1985). They also found evidence that
there is acorrelation between compound solubility and sorption,
substantiating earlier studies. Reynolds et al., (1990) found
diffusivity decreased as mean molecular diameter increased
which agrees with a study performed by Berens and Hopfenberg
(1982), based on polymeric diffusivity tests.
They suggest the use of PTFE in monitoring wells in areas where
higher concentrations might be encountered, for instance near
a solvent spill. Their study showed a polymer exposed to high
concentrations of an organic compound that is agood solvent for
the polymer, that the polymer will absorb large quantities of the
solvent and swell. However, it is difficult to predict the swelling
power of various solvents. As an example, rigid PVC can absorb
over 800 percent of its weight in DCM but only 1 percent of CCL4.
Schmidt (1987), however, found no swelling or distortion of rigid
PVC casing or screen when exposed to various gasolines for 6.5
months.
Taylor and Parker (1990) visually examined PVC, PTFE,
SS304, and SS316 with a scanning electron microscope (SEM)
to determine how they were affected by long-term exposures (1
week to 6 months) to organic compounds. Organics used in this
test were PDCB, ODCB, toluene, and PCE at concentrations of
17.3,33.5,138, and 35.0 mg/L, respectively (approximately 25
percent of their solubilities in water).
SEM examinations showed no obvious surface structure
changes for any of the materials exposed to the different
concentrated organic aqueous solutions. They caution, how-
ever, that this study cannot be extended to instances where
casing materials are exposed to pure organic solvents. They did
not report the amount of compound sorbed by the different
casing materials.
Inorganic Studies
Massee et al., (1981) studied the sorption of silver (Ag), arsenic
(As), Cd, selenium (Se), and Zn from distilled water and artificial
sea water by borosilicate glass, high-pressure PE, and PTFE
containers. The effect of specific surface (R in cm1), i.e., the
ratio of the surface area of the material in contact with the
solution, to the volume of the solution, was also studied. Metals
were added to the distilled and artificial sea water. The pH levels
of the aqueous solutions used were 1, 2, 4, and 8.5. Water
9
-------
samples were tested at intervals ranging between 1 minute and
28 days. Losses of As and Se were insignificant for all the
treatments. At pH levels of 1 and 2, no significant sorption from
either distilled water or artificial sea water was observed for any
of the containers or metals used in this study. Test results of the
sorption of Ag, Cd, and Zn from distilled water and sea water are
presented in Tables 7 and 8, respectively.
The results showed PTFE sorbed substantial amounts of Ag,
Cd, Zn, and the amounts sorbed were dependent on the pH and
salinity of the solutions. Specific surface was found to have a
significant effect on the sorption of metals by PTFE. For
example, at the end of 28 days the loss of Ag to PTFE with R =
5.5 cnr' was almost 4 times higher than for R = 1.0 cm4.
Massee et al., (1981) concluded that sorption losses are difficult
to predict because the behavior of trace elements depends on
a variety of factors such as trace element concentration, mate-
rial, pH, and salinity. They noted that a reduction in contact time,
specific surface, and acidification may reduce sorption losses.
Miller (1982) conducted a study to determine the potential of
PVC, PE, and PP to sorb and release Cr(VI) and lead (Pb) when
in a Cr(VI)-Pb solution and in a solution of these two metals
along with the following organics; BRO, PCE, TCE,
tricbioroflurometbane, 1,1,1-TCA, and 1,1,2-trichioroethane.
Tables 9 and 10, respectively, present the results for the Cr(VI)
and Pb adsorption and leaching studies. The results showed
that none of the materials tested adsorbed Cr(VI) to any signifi-
cant extent when in a solution with Pb. When in a solution with
Pb and 6 other organics, 25 percent of Cr(VI) was adsorbed by
the 3 casing materials. No leaching of Cr(Vl) was observed from
any of the materials either in the metals only or metals and
organics solutions. Seventy-five percent of the Pb was
adsorbed by PVC when in a solution with Cr(VI) and also when
in a solution of Cr(VI) and the six organics. PE and PP showed
about 50 percent adsorption of Pb when in a solution with Cr(V I).
The casing materials did not leach any Pb when in a solution with
Cr(VI); however, when in a solution with Cr(Vi) and 6 organics,
the 3 casing materials leached approximately 50 percent of the
Pb initially adsorbed. In his study, Miller found that PVC
TABLE 7. SORPTION BEHAVIOR OF SILVER, CADMIUM, AND ZINC IN TABLE 8. SORPTION BEHAVIOR OF SILVER, CADMIUM, AND ZINC IN
DISTILLED WATER ARTIFICIAL SEA WATER
Material PE
BorosWcate
Glass
PTFE
PH
4
8.5 4

8.5

4
8.5
R(cnr')
1.4 3.4 1.0 3.4 1.0 4.2
1.0 4.2 1.4 53 1.0
Contract
Metal Time
Sorption (%)

Ag 1 hour
10
15 25 36 *
4
9
21
« t
*
1 day
25
66 72 49 32
18
26
48
4 6
5
26 days
96
100 59 100 82
80
72
63
15 55 22
Cd 1 hour

• 7 69 *
•
6
26
* t
7
1 day
•
' * 47 *
' •
10
32
* *
10
28 days

15
Zn 1 tour
*
* • 65 *
*
23
22
* ~
3
1 day
• . ¦
* a 56 *
•
26
22
* *
5
28 days
*
* 12 56 *

6
'Denotes a loss sm
•allei
1

(Source: Massee et el., 1981 j
Material PE
pH 4 8.5 4
R(cnr') U 3.4 1,0 3.4 1.0 4.2
Contact
Metal Time SOfpttoii(%)
Boroaillcate
Glass PTFE
10 Ag
Zn
1 hour
* * 6 5 *
•
3
3 *
» *
1day
* * 24 » 4
4
6
9 *
* 6 «
28 days
Slillit®
71
40
67 *
• 27 ST;
Cd
1 hour *«**•»
1 day
* * * * 14 36
' ' t < ~
1 hour *- - * * * •
t day **,*¦?• * *
28 days * » *> * -20 19
18.5 4- 8.5
1.0 4.2 1.4 5.5 1.0 5.5

'f-yf
9 31
• « *

5 26 4 '
4 9 5
. * «
(Source: Massee etaJ., 1981)
10
-------
TABLE 9. TRENDS OF CHROMIUM (VI) EXPOSED TO SYNTHETIC
WELL CASING (COMPARED TO CONTROLS)
Adsorption
Adsorption/Leaching
Casing
Material
Metais
Only
Metais and
Organics
Metals
Only
Metals and
Organics
PVC
No adsorption
Slight (25%)
adsorption
No leaching
No leaching
PE
No adsorption
Slight (25%)
adsorption
No leaching
No leaching
PP
No adsorption
Sip (25%)
adsorption
No leaching
No leaching
(Source: Miller, 1982)
TABLE 10. TRENDS OF LEAD EXPOSED TO SYNTHETIC WELL
CASING (COMPARED TO CONTROL)
variables (i.e., pH, TOC, and concentration). SS304 and SS316
showed evidence of corrosion near cuts and welds which may
provide active sites for sorption and release of contaminants.
Hewitt (1989a) concludes PTFE is the best material for monitor-
ing the metals used in this study whereas, SSs are not suitable.
He states that although PVC was affected by Cd and Pb it should
still be considered as a useful casing material based on econom-
ics, and that when the time between purging and sampling is less
than 24 hours, the effects of Cd and Pb on PVC may be of less
concern.
Hewitt (1989b) conducted a study to determine the amounts of
barium, Cd, Cr, Pb, Cu, As, Hg, Se, and Ag leached from PTFE,
PVC, SS304, and SS316 in ground water. Table 11 summarizes
the results of the investigation. Results indicate that PTFE was
the only material tested not to leach any metals into the ground-
water solution. PTFE, however, did show a trend to sorb Cu with
time. PVC and SS316 showed a tendency to leach Cd; in
addition, these two materials, along with SS304, sorbed Pb.
PVC was also shown to leach Cr and provide sorption sites for
Cu. SS316 significantly increased the concentration of Ba and
Cu in the ground-water solution. SS304 consistently contrib-
uted Cr with time to the ground-water solution. None of the well
casing materials contributed significant levels of As, Hg, Ag, or
Se to the ground water.
Adsorption
Adsorption/Leaching
TABLE 11. SUMMARY OF RESULTS
Casing
Material
Metals Metais and
Only Organics
Metals
Only
Metais and
Organics
PVC
Mostly (75%) Mostly (75%)
adsorbed absorbed
No leaching
Mostly (75%)
absorbed
PE
Moderate (50%) Moderate (50%)
adsorption adsorption
(delayed)
No leaching
Mostly (75%)
adsorbed
PP
Moderate (50%) Slight (25%)
adsorption adsorption
(delayed)
No leaching
Mostly (75%)
adsorbed
(Source: Miller, 1982)
generally causes fewer monitoring interferences with VOCs
than PE and PP and that PVC adsorbed and released organic
pollutants at a slower rate relative to PE and PP.
Hewitt (1989a) examined the potential of PVC, PTFE, SS304,
and SS316 to sorb and leach As, Cd, Cr, and Pb when exposed
to ground water. The pH, TOC, and metal concentrations of the
solution were varied and samples taken between 0.5 anfl/v
hours. The study showed that PTFE had the least-active
surface and showed an affinity only to Pb (10 percent sorption
after 72 hours). PVC and SS leached and sorbed some of the
metals tested. PVC was a source for Cd and sorbed Pb(ZB
Percent sorption after 72 hours). The SSs were the most active
of the materials tested. SS304 was a source of Cd and sorbed
As and Pb. SS316 was also a source of Cd and sorbed as, ua,
and Pb. The study showed results were affected by the solution

Bi
Cd
Cr
Pb
Cu
Materials that leached
>1% of the EPA
drinking water quality
level in ground-water
solutions
SS316
PVC
SS316
PVC
SS304
SS316
PVC
SS304
PVC
SS316
NA*
Materials that showed
the highest average
overall amount of
analyte leached
SS316
SS316
SS304
SS304
SS316
'Does not apply
(Source: Hewitt, 1989b)
Hewitt (1989b) concludes PTFE is the best casing material
when testing for trace metals while SS should be avoided. He
also states PVC is an appropriate second choice because its
influence on metal analytes appears to be predictable and small.
Casing Material Coat Comparison
A consideration when installing monitoring wells is cost. Costs
to be considered in the installation of monitoring wells are cost
of construction materials, drilling costs, and expected life (re-
placement costs) of the casing material. Table 12 presents a
cost comparison among five casing materials: PVC, SS304,
SS316, PTFE, and FRE. The prices shown were obtained from
Brainard-Kilman (1990) with the exception of the FRE casing,
11
-------
TABLE 12. CASING MATERIAL COST COMPARISON
Prices reflect the cost of ten 10-ft long by 2-in. diameter casing sections, a
5-ft long 0.010-in slotted screen, and a bottom plug.
Casing Material Price
PVC* • $ 179.50
FRE" 966.00
SS304 1,205.00
SS316 1,896.00
PTFE 3,293.50
'Schedule 40 PVC
" Low Sow screen
whose price was provided by ENCO (1989). The cost estimates
are for ten 10-feet sections (100 feet) of 2-inch threaded casing,
5 feet of 0.010-inch slotted screen, and a bottom plug.
The cost of materials for 1 PTFE well is approximately 18 times
greater than 1 constructed on PVC (Table 12). At first glance,
PVC, by far, is the most economical material for constructing
monitoring wells. However, if drilling and material (bentonite,
cement, sand, etc.) costs are considered, the percent difference
in cost between PVC wells and wells constructed of SS, FRE, or
PTFE is reduced.
For example, assume that the cost of installing, materials, and
completing a 100-feet deep monitoring well (exclusive of casing
material costs) in unconsolidated material is $5,000. When the
cost of casing material is added to the drilling and materials
costs, a PVC-cased well costs $5,179.50 and an SS316-cased
well $6,896.00. When drilling and materials costs are consid-
ered, a PVC-cased well costs approximately 25 percent less
than a SS316-cased well. However, when drilling and materials
costs are not taken into account, PVC casing looks especially
attractive since it is approximately 90 percent less expensive
than SS316 casing. In this case, a SS316-cased well may be
considered to be cost effective especially if organ ics are ex-
pected to be sampled. Thus, the significance of the "cost of
casing materials versus ground water-casing interaction" issue
is reduced.
CONCLUSIONS
All aspects of a ground-water sampling program have the
potential to introduce error to a ground-water sample. Interac-
tion between monitoring well, casing materials and ground
water is only one of the ways in which error may be introduced
in a sampling program. Presently, there are a variety of
materials available lor fabricating monitoring wells. The poten-
tial for these casing materials to interact with ground water has
found to be affected by many factors, including pH and compo-
sition of the ground water and the casing-ground water contact
time. The complex and varied nature of ground water makes it
very difficult to predict the sorption and leaching potential of the
various casing materials. Consequently, the selection of the
proper casing material for a particular monitoring application is
difficult. This is evidenced by the lack of agreement among
researchers on which is the "best" material. The problem is
compounded by the inconclusive and incomplete results of
laboratory studies on the effects of rigid well casing materials
with inorganic or organic dissolved species.
Many of the experiments examined the effects of time on the
sorption and leaching potential of the various casing materials.
The experiments were usually run under laboratory conditions
in which distilled or "organic free" water was used and casing
materials were subject to contaminants for periods ranging from
minutes to months. These experiments, in general, indicate a
trend for the materials to be more reactive with the aqueous
solutions with time. Experiments showed if the time between
well purging and sampling is relatively short, some of the more
sorptive materials could be used without significantly affecting
sample quality.
The selection of appropriate materials for monitoring well casing
at a particular site must take into account the site hydrogeology
and several general requirements. Thesegeneral requirements
for the screens and casing of wells that are used for ground-
water monitoring are the following:
1. Depth to zones being monitored and total depth of well must
be considered.
2. The geochemistry of the geologic materials over the entire
interval in which the well is to be cased and screened must
be taken into account.
3. The wells must be chemically resistant to naturally occurring
waters.
4. The well materials must be chemically resistant to any
contaminants that are present in any and all contaminated
zones of the aquifer or aqyifers being monitored.
5. The strength of the materials must be physically strong
enough to withstand all compressive and tensile stresses
that are expected during the construction and operation o*
tiie monitoring well over the expected lifetime.
6. Installation and completion into the borehole during
construction of the monitoring well must be relatively easy-
7. The well materials must be chemically resistant to any
anticipated treatments which are strongly corrosive or
oxidizing.
It may be necessary to conduct site-specific, comparative p®[*
formance studies to justify preference for a particular well casi™
or screening material over another.
12
-------
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13
-------
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14
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ABBREVIATIONS
1,1-DCA 1,1-Dichloroethane
1,1,1-TCA 1,1,1-Trichloroethane
1,1,2,2-TET 1,2,2,2-Tetrachlorethane
1,2-DCA 1,2-Dichloroethane
2,4,6-TCP 2,4,6-Trichlorophenol
ALS Acrylonitrile butadiene styrene
Ag Silver
As Arsenic
ASTM American Society for Testing and Materials
BRO Bromoform
c-1,2-DCE cis-1,2-Dichloroethylene
CC14 Carbon tetrachloride
Cd Cadmium
CHCI3 Chloroform
Cr Chromium
Cu Copper
DCM Methylene chloride (dichloromethane)
DNT 2,4-Dinitrotoluene
EMSL-LV Environmental Monitoring Systems Laboratory-
Las Vegas
FRF Fiberglass reinforced epoxy
HCE Hexachloroethane
Hg Mercury
HMX Octabydro-1,2,5,7-tetranitro 1,3,5,7-tetrazocine
m- Meta
MCB Chlorobenzene
MDCB m-Dichlorobenzene
MNT m-Nitrotoluene
MPL Maximum permissible levels
NSF National Sanitation Foundation
o- Ortho
ODCB
o-Dichlorobenzene
P-
Para
Pb
Lead
PCB
Polychlorinated biphenyl
PCE
Tetrachloroethylene
PDCB
p-Dichlorobenzene
PE
Polyethylene
PH
Hydrogen ion concentration of the solution
pK
Log dissociation constant
PP
Polypropylene
ppb
Parts per billion (by weight)
PPm
Parts per million (by weight)
PTFE
Polytetrafluoroethylene (Teflon®)
PVC
Polyvinylchloride
RCRA
Resource Conservation and Recovery Act
RDX
Hexahydro-1,3,5,7-trinitro-1,3,5-triazine
RVCM
Residual vinyl chloride monomer
Se
Selenium
SEM
Scanning electron microscope
SS
Stainless steel
SS304
Stainless steel 304
SS316
Stainless steel 316
t-1,2-DCE
trans-1,2-Dichloroethylene
TCE
Trichloroethylene
TEGD
Technical Enforcement Guidance Document
TNB
Trinitrobenzene
TNT
2,4,6-Trinitrotoluene
TOC
Total organic carbon
U.S. EPA
U.S. Environmental Protection Agency
VOC
Volatile organic compound
Zn
Zinc
15
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United States Office of Office of Solid EPA/540/S-92/019
Environmental Protection Research and Waste and August 1992
Agency Development Emergency
Response
4>EPA Ground-Water Issue
POTENTIAL SOURCES OF ERROR IN GROUND-
WATER SAMPLING AT HAZARDOUS WASTE SITES
K. F. Pohlmann and A. J. Alduino
INTRODUCTION
The Regional Superfund Ground Water Fo-
rum is a group of ground-water scientists
representing the U.S. EPA's Regional
Superfund Offices that was organized to ex-
change up-to-date information related to
ground-water remediation at Superfund sites.
The introduction of error during ground-water
sampling is an issue identified by the Forum as
a concern of Superfund decision makers.
To address this issue, this paper was pre-
pared under the direction of K. F. Pohlmann of
the Desert Research Institute/Water Re-
sources Center, with the support of the Envi-
ronmental Monitoring Systems Laboratory -
Las Vegas (EMSL-LV) and the Superfund
Technical Support Project For further infor-
mation contact Ken Brown, EMSL-LV Tech-
nology Support Center Director, at 702/798-
2270 or K. F. Pohlmann at 702/895-0485.
Acquisition of ground-water samples that ac-
curately represent in situ physical, chemical,
and biological conditions is critical to all
phases of Superfund site investigations.
Nonrepresentative data collected during the
remedial investigation (Rl) may interfere with
the characterization of site hydrogeoiogy,
contaminant distribution, and the determina-
tion of whether ground water is providing a
pathway for migration of waste constituents
away from the site. The feasibility study (FS)
phase of the investigation depends on repre-
sentative data to adequately define the opti-
mal remediation technologies for the site. Fi-
nally, accurate data are required during the
remediation phase to determine whether re-
medial actions are functioning effectively.
Sample error is defined here as the deviation
from in situ values of hydrochemical param-
eters and constituents caused by the conduct of
ground-water sampling investigations. Errors
in ground-water quality data reduce the ability of
samples to accurately represent in situ ground-
water conditions resulting in increased variabil-
ity of analytical results and weakened confi-
dence in ground-water data. As a conse-
quence, the objectives of the site investigation
may be jeopardized. To ensure representative
data, it is necessary to identify, evaluate, and
reduce potential sources of error for every as-
pect of the sampling program. Errors that are
most difficult to identify may be the most critical
to sampling programs because important con-
clusions may be unknowingly based on errone-
ous or inadequate data.
PURPOSE AND SCOPE
This paper-is intended to familiarize. RPMs,
OSCs, and field personnel with the sources of
error inherent to ground-water sampling, and
the relative impact of these errors on sample
representativeness. Elements of typical sam-
pling protocol will be discussed in relation to
how these sources of error can be identified and
minimized. Where possible, the error associ-
ated with a particular method or material will be
quantified and the elements ranked as to their
potential for adversely impacting sample repre-
sentativeness. Some of the elements of sam-
pling protocol to be addressed include monitor-
ing well drilling, design, construction, and purg-
ing, sample collection methods and devices,
sample filtration, equipment decontamination,
sample transport and storage, and analytical
methods.

S I"~" 1
o aw a
Superfund Technology Support Center for
Monitoring and Sit# Characterization
Environmental Monitoring Systems Laboratory
Las Vegas, NV
Technology Innovation Office
Office of SoKi Waste arid Emergency Response,
U.S. EPA, WariiiigtQn, D.C
Waller W. Kovalck, Jr., Ph.D., Director
Printed on Recycled Paper
-------
Each Suparfund sit* has uniqua gaotogic, hydrologic, biologic
and chamioal conditions that may influanca tha typa and mag-
nituda of potantial sampia arrors. This papar providas an
ovarviaw of sampia arror; typas of error potantially important at
sach sita must ba avaluatad on an individual basis. Furthar-
mora, whila this papar will ramain static, tha conduct of sita
invastigations will ba in a constant stata of flux as naw tachnd-
ogy is davalopad and as tha undarstanding of contaminant
transport and fata and tha sampling procass is improvad. As a
rasult, sourcas of sampling arror dascribad harain may ba
rasolvad through tha application of naw tachnology and math-
ods whila naw sourcas of arror ara likaly to ba idantifiad.
MONITORING WELL DESIGN
Tha dasign of ground-watar monitoring installations must ba
consistant with geologic, hydrologic, and hydrochamical condi-
tions to obtain raprasantativa ground-watar sampias. Important
aspacts of monitoring wall dasign incktda tangth of wall irrtaka
intarval, dasign of tha fikar pack and scraan, dasign and instal-
lation of boranola saais, and wall location.
Tha langth and location of wall intakas hava important affacts on
tha dagraa with which sampias raprasant ground-watar condi-
tions. Long wal intakas (long scraans) ara opan to a larga
vartical intarval and tharafora ara mora likaly to provida sampias
that ara a compoaita of tha ground watar adjacant to tha antira
intaka. Convarsaly, short intakas (short scraans) may ba opan
toas'mgla strata or zona of contamination and ara mora Ikaty to
provida sampias that raprasant spacific dapth intarvaJs. Walls
thai ara scraanad ovar mora than ona dapth intarval (muM-
scraanad walla), ragardlaasof thair acraan langtha, may impact
ground-watar conditions and sampias in much tha sama way as
long-acraanad walls.
Long-scraanad walla hava baan suggaatad as baing mors cost
affactiva in dataction monitoring than savaral thort-scraanad
walls bacausa thay sampia graatar vartical tactions of aquifars
(Giddings. 1986). Howavar, pwnping-inducad vartical flow in
walls with long scraans can impact ground-watar flow and
contaminant oonoantratJona naar tha wad (Kalaris, 1999). In
addition, whan groundwater contamination is vertically strati-
fiad. compoaita sampias ooKactad from a long-scraanad wad
rapraaant soma sort of avaraga of ooneantmkma adjacant to
tha scraan, and provida llttls information about tha concantra-
tions in individual strata, kv particular, in casaa whara contami-
nants may baof low ooncantration and rastrictad to thin zonaa,
bog-acraiwad wads may.laad to dilution of tha contaminants to
tha point whara thay may ba difficult to datact (Cohan and
R^SoW, 199?). Ukawiaa, long-aoraan walls intarsacting con-
taminants of (Wfaring danaltiaa may alow dansity-drivan mixing
within tha wad bora and subsaquant dilution of contaminant
concantrations (Robin and GiMham, 1987). Tha usaof inflatabia
packars to isolata spacific zonas within a long scraan may not ba
an affactiva solution bacauaa ground watar may flow varticafly
through tha filtar pack from othar zonas in rasponsa to tha
raducad hydraulic haad In thapaek*d4ff zona during sampling.
Vartical haad gradiants in aquifars naar long-scraanad walla
may laad to arror in two ways: (1) if contaminants ara moving
through a zona with low hydraulic haad, claanar watar moving
from zonas of highar haad may diluta tha contaminants, laading
to dataction of artificially low concantrations, and, (2) if highar
concantrations of contaminants ara moving through a zona of
high hydraulic haad, cross-contamination batwaan watar-baar-
ing zonas may occur via tha wall bora (Mcltvrida and Ractor,
1986). Thasa workars dascriba a casa history in which two
aquifar zonaa wara idantifiad at a sita, with only tha top zona
contaminatad with VOCs. Walls scraanad only in tha contami-
nate zona rasultad in dataction of VOCs in tha faw hundrad jig/
L ranga whila sampias collactad from long-scraanad walls opan
to both intarvals showad no VOC contamination. A numarical
flow modal of a long-scraanad wall davalopad by Railly at al.
(1989) damonstratad that vary low haad gradiants can laad to
substantial cross-flow within long-scraanad walls. At sitaa
whara dalinaation of vartical hydraulic and concantration gradi-
ants is important, arrors can ba raducad by utilizing a systam of
nastad short-scraanad walls that can mora accurataly charac-
tariza tha oontaminant distribution.
MultHaval sampling davicas provida an altamativa monitoring
tachniqua in situations whara vartical haad gradiants ara impor-
tant or whara contamination is vartieaily stratifiad. Thasa
davicas can ba installad in such a way that individual zonaa can
ba aampiad saparataiy without vaiticai movamant of ground
watar or contaminants batwaan zonas. Using a multttaval
davica, Smith at al. (1987) datactad a zona containing nit rata
concantrations ovar 10 mg/L that had baan praviously undatac*
tad by obaarvation walls with two-foot scraans. Tha sampiat
from tha muMtaval sampiar also datactad larga vartical grad*
ants in aiactrical conductivity (EC) and chtorida that wara not
datactad with tha monitoring walls.
Rasidantial and municipal watar-supply walls that ara oftan
uaad during aarty phasas of Rl programs ara ganarally con*
structad with long scraans, tharafora concantrations of contami*
nants in sampias coiiactad from thasa walls may not rTTr"iflt_
ambiant ground-watar concantrations. Whan dafining human
racaptors this may not ba an iaaua bacausa tha ovarall quality
of ground-watar axtractad from watar-suppiy walla may not
raflact tha quality of watar in individual strata. In thasa caaaa.
dilution may raduca concantrations of contaminants to within
haaith-baaad standards. Howavar, gross arrors may ba Intro-
duoad into tha analysis if thasa concantrations ara uaad for
dataflad dalinaation of tha gaomatry and concantrations of
oontaminant piumaa or dataction cA contaminants at vary tow
concantrations.
To mitigate hazards, wasta managamant options at Suparfund
sitaa may induda ramadiation of contaminatad ground watar by
pumping and traatmant. Long-scraan watts ara oftan tha most
affactiva for attraction of ground watar bacausa thay ara hfe
draulicaHy mora affidant than wails with short scraans. Ho#*
avar, bacausa accurata ground-watar contaminant concantra*
tions cannot ba datarminad from thasa wads K may ba naoaa*
saiy to install saparata walls for monitoring tha prograss flf
ground-watar axtraction and traatmant.
Fllttr Pack m* W§U lntak§
Suspandad solids that originata from drilling activitias or a«|
mobilizad from tha formation during davalopmant, purging,#
sampling may disrupt hydroahamical aquilibrium during sampH
collaction and shipmant. A proparly daaignad combination 9f
2
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filter pack and wall intaka provida* an aff iciant hydraulic connec-
tion to a water-bearing zona and minimizes the suspended
solids content of sampled water. However, to be most effective,
filter pack and well intaka design must be based on the sedi-
ments encountered in each borehole. Inadequate well perfor-
mance resulting from application of a generic well design may
lead to incomplete well development and high suspended solids
content in samples. Descriptions of the methods of filter pack
and intake design can be found in Driscoll (1986) and All or et al.
(1989).
Artificial filter packs should be composed of a chemically-inert
material so as to reduce the potential for chemical alteration of
ground water near the wed. Clean silica (quartz) sand is
generally recommended and widely used because it is
nonreactive under most ground-water conditions. Other types
of materials may induce chemical changes. For example, filter
pack materials containing calcium carbonate, either as a pri-
mary component or as a contaminant, may raise the pH of water
that it contacts and lead to precipitation of dissolved constituents
(Alter et al., 1989).
The use of a tremie pipe to install filter pack materials minimizes
the potential for introducing sample error to this phase of well
construction. Dropping filter pack materials directly into an
uncased borehole may lead to cross-contamination by mobiliz-
ing sediments or ground water between depth intervals. Fur-
thermore, installation of filter pack materials by methods which
Introduce water to the borehole may modify hydrochemistry to
an unknown extant or add contaminants to the sampling zona.
Water-based methods may also lead to cross-contamination
within the borehole.
Bonho* Sm/«
Borehole seals, generally composed of expandable bentonite or
cement grout, are well-known as potential sources of sampling
error. The expandable bentonite clay used in many seals has
high ion exchange capacity which may alter major ion composi-
tion of water(GUIIham et al., 1983) or concentrations of contami-
nants that form complexes with these ions (Herzogetal., 1991).
The effects of these reactions are seldom revealed by measure-
ment of field parameters and normally-conducted analyses, but
in eases of extreme sodium bentonite contamination may be
seen as abnormally high sodium concentrations.
Cement grout can also significantly influence ground water
chemistry, particularly K the grout doesn't set property. Contami-
nation by grout seals, which generally results from its calcium
carbonate content and high akalinity, may be identified by
elevated calcium concentrations, pH (generally over 10 pH
units), EC, and akalinity (Barcelona and Heifrich, 1988). These
workers found that cement contamination of several wefa
persisted for over 18 months after wefl completion and was not
reduced by ten redevelopment efforts. Barcelona etai. (1918a)
indicate that solution chemistry and the dstribution of chemical
species can be impacted by cement contamination although
thee* impacts have not been quantified to dale. Inbw-perme-
abWty sediments, the impacts of grout materials may be much
greater due to insufficient flushing of the installation by moving
groundwater.
Contamination from borehole seals can be minimized by sepa-
rating the seals from sampling zones by fine-grained transition
sand, estimating the volume of seat material required before
installation to more easily detect bridging problems during
emplacement and by allowing sufficient time for the seals to set.
In addition, cement grout can be isolated from sampling zones
by installation of a bentonite seal. Error can also be reduced by
installing boreholes seals with a tremie pipe. Dropping seal
materials directly into an uncased borehole may lead to cross-
contamination by mobilizing sediments or ground water be-
tween depth intervals, or may contaminate sampling zones if the
seal materials are dropped past the sampling zone depth.
Furthermore, installation of seal materials by methods which
introduce water to the borehole may modify hydrochemistry to
an unknown extent or introduce contaminants to the sampling
zone. Water-based methods may also lead to cross-contamina-
tion within the borehole.
WW/ Location
The location of monitoring wells with respect to ground-water
contaminant plumes is important to the accurate depiction of
contaminant movement and concentration distribution, espe-
cially in areas where concentration gradients are large. A
discussion of optimum wel placement is beyond the scope of
this document, but aspects of this topic can be found in the works
of Keith et aL (1983), Meyer and BrW (1988), Scheibe and
Lettenmaier (1989), SpruiH and Candela (1990), and Andricevic
and Fotrfoula-Georgiou (1991). These investigators discuss
various aspects of monitoring wed network design and how
monitoring weH coverage of the area under investigation relates
to accurate quantification of spatial variation in hydrochemical
parameters. Generally implied within network design is the
reduction in error associated with delineating spatial variation.
Sampling from wells whose locations were determined without
adequate consideration of network design and geologic, hy-
draulic, and hydrochemical conditions may lead to significant
errors in data interpretation and conclusions. For example,
resolution of concentration distribution may be reduced in areas
where walla spacing intervals are too large for the scale of the
investigation.
To summarize the topic of monitoring well design, collection of
aocurate ground-water quality data in three dimensions is
strongly dependent on the design of the ground-water monitor-
ing system, including both individual wells and wed networks.
Significant errors can be introduced into sampling data, and the
resultant condueione, if well intakee and filler packs are not
desianed tor ambient conditions, or are plaoad at inappropriate
depths or over excessive vertical intervals, or If borehole seals
are improperly installed. Furthermore, the design of monitoring
weH networks may introduoe error by inadequately repreeenting
spatial variation through Inadequate oeverage of the site. Al-
though the magnitude of theee errors is heavfly dependent on
the geologic, hydraulic, and hydrochemical conditions present
at a particular site, order of magnitude effects are easily within
the realm of poesfcity.
DRILLING MSTHQOS
long-term or permanent dieturbance of hydrooeoiogie and
hydrochemical conditions may result from the drilling method
used for monitoring well installation. possiMy leading to signifi-
cant error during subsequent ground-water sampling. Drilling
methods may disturb sediments, alow vertical movement of
ground water and/or contaminants, introduce materials foreign
3
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to the subsurface, and clog void spaces. Tha axtant to which
conditions ara aftarad depends on tha drilling method utilized
and tha nature of tha gaologic materials (Qillham, at al.. 1983).
in addition, tha properties of tha contaminants at tha sita will
irrfluanca thair sanaitivity to tha impacts of drilling.
introduction of a diffarant watar typa may add contaminants
disrupt hydrochamical equilibrium and causa precipitation of
dissolvad constituents. During sampling, some of these precipt-
tatas may ba radissolvad by ground watar flowing toward th«
watt causing non-representative sampias.
Monitoring walla ara oommoniy constructed by augar, rotary,
drill-through casing, and cable-tool methods. Augar drilling
methods utilize hollow- or solid-stem augar flights and ara
generally restricted to use in unconsolidated materials. Rotary
techniques ara classified based on the composition of the drilling
fluid (water, air, and various additives), the mode of circulation
(direct or reverse), and the type of W(e.g. roller cone, drag, or w».. v.
button) and are adaptable to most geologic conditions. Tha drill- additives can introduce organic carbon into ground water arM
through casing method utilizes rotary or percussion drilling provide a substrata for microbial activity leading to errora £
techniques but uaes a casing driver to advance temporary ¦—' —~«i—-i—-
casing in conjunction with tha advancing borehole. Incable-tool
drilling, the borehole is advanced by alternately raising and
lowering a heavy string of drilling tools suspended from a cable.
Temporary casing can also be advanced as drilling progresses
The bentonite additives used in many drilling fluids have a high
capacity for ion exchange and may alter hydrochemistry Of
ground-water samples if not completely removed from th«
borehole and surrounding formation (Qillham at al., 1983). lori
exchange reactions that alter major ion composition may also
affect the concentrations of contaminants that form complexes
with theae ions (Herzog at al., 1991). Organic polymeric
Some drilling methods may altar the hydrogeologic environment
by smearing cuttings (particularly fine sediments) vertically
atong the borehole wall. This action may form a mudcake that
cm reduce the hydraulic efficiency of the borehole wall and
modify ground-waler flow into the completed well (Mcllvride and
Wsias.1988). Smearing may alsotransportsediments between
zones and alter the vertical distribution of contaminants
adsorbed ontotheeeeedimente. In addition, methods that mix
sedmentshorizontaly near the waN bore may affect the trans-
port of oontaminants near the completed weN (Morin, at al.,
1988).
Vertical movement of ground watar may oocur during drilling,
primarily in situations wharo the borehole remains uncased
during driing operations. Ground water can be transported
vertically by circulating drilling fluid or by hydraulic head differ-
ences between zones, in situations where contaminated
ground wafer is vertically strajWed, vertical ground-water move-
ment may cause cross-contamination within the well-bore and
adjacent formation (Qttham at ei., 1983). Movement of ground
water and contaminants between zones may also disrupt
hydrochamical equilibrium near the wed.
DriMna adMtiee can alter hvdrachsmistrv as a result of contact
wkh introduced matsrials foreign to 0ie sutoeurfaoe environ-
ment ForaM»ipfc,lubricanl>orhydraufcfkiklsmayenterthe
botshole directly by faMngfrom trie driHng rig or may enter
indfeeotyvtadriling fluids. In the latter case, oontaminants may
Oriajaate in mud pumps, air eomprsesors, or down-hole driing
shipment Sale orothermatsrialfrom the driing site may also
ifliii
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TABLE 1. POTENTIAL MPACTS OF DMJJNQMETHOOS ON
GROUND-WATER SAAPLE OUAL/TY
Mstwd Potential Impacts
Aug* DrMng fluids ganaraly not uaad but walar or
othar material* addad if haawing sands ara
ancountarad may afler hydrochamistry
Smearing of finasedbnafits along borstals wal
Vertical movement of ground water andfer
oomammara wivvnoorvnoit
Lateral mixing of aadtaants naar wal bora
Rotary OrMng fluids aieiequirad and may cause croaa-
oontaminalion, vertical smearing of sadbnants.
¦Iteration of hydrochamiHry. and introduction of
contaminants
Smaaring of finasadbnants along borahola wal
venra momrm* ov yrouno wmi ano/or
contaminants wlhin borstals
Drive-Thraugh-Caaing DrMng fluids raquirad but advancing casing
raduoaa potantial tar drHng fluid Iom, craaa-
oontamindlon, and vartical smaaring of
sadbnanti, ground waisr, and oontaminants.
Cable Tool Advancing casing reducas potential lor cross-
contaminaiion, and vartical smaaring of
sadknants, ground wstsr, and contaminants.
in monitoring walls by several methods including surging with a
surge block mechanism, surging and pumping with compressed
air, pumping and overpumplng with a pump, jetting with air or
water, backwashing with water, and bailing. Al of these meth-
ods have the potential (to varying degrees) to influence the
quality of ground water samples; the extent depends on the
nature of their action and the condition of the sampling zone after
drilling.
Development should be considered complete when representa-
tive samples can be collected and can continue to be collected
Indefinitely. Unfortunately, under moat ground-water sampling
dreumstaneea determining when samples are rapreeentative of
in situ oonditions is not possible, so some related criteria are
often chosen. Ideally, these criteria should include (1) the
production of dear water during development, and (2) the
removal of a volume of water at least equal to the amount loet to
the formation during drifling and wed instaflatk>n(Kraemeretal.f
1991). In addition, certain oonditions may require that develop-
ment be oontinued after the wen has been aflowad to recover
from the first round of development efforts. This condition may
exist if the first round of aamplea exhbit turbidity.
Incomplete or ineffective well development may allow drilling
and other introduced fluids to remain in the sampling zone or
may not remove all mudcake or smeared sediments from the
borehole wall. The preaence of these materials may introduce
error by disrupting hydrochemicel equilibrium or by introducing
contaminant! to the wed or aampling zone. In addition, these
materials can reduce the hydraulic conductivity of the filter pack
and formation and modify ground water flow near the well before
and during sampling.
Development methods thet utilize eir pressure can entrap air in
the filter peck end formation, diarupt hydrochemical equilibrium
through oxidation, or introduce contaminants from the air stream
to the formation and filter pack. These effects may be reduced
if precautiona are taken to eliminate air contact with the well
intake. The addition of water during development mey modify
hydrochemistiy to an unknown extent or mey introduce contami-
nants to the sampling zone, even if ad the water is removed
during development In Hght of theae potential probleme, jetting
methods thet inject air or water directly above the well intake are
not reoommended (Keely end Boateng, 1967). Likewise, other
methods that introduce air or water to the well (surging and
pumping with compressed air, and backwashing, for example)
also may not be suiteble for monitoring well development (Aller
etal., 1989).
Development of weda at very high rates may displace fitter pack
and formation materiels and reduce the effectiveness of the filter
pack, particularly if the method involves excessive surging
(Keely and Boateng, 1967). On the other hend, development at
low rates (as is generally attained with sampling pumps) may not
provide enough agitation to meet development objectives
(Kraemeretel., 1991). In many monitoring well situations, using
surge-block methods to loosen material and either pumping or
bailing to remove the materiel hea been found to be en effective
development technique (Aller et al., 1989).
In low-yield weda, surging methods may result in exceesive
mobilization of fine-grained materiels. For example, in a study
conducted in fine-grained glacial tills. Paul et al. (1968) found
that auger-drilled wels developed by surge-block methods
produced samples with up to 100 times greater turbidity than
samples from simflar weds developed by bailer. In addition, the
turbidity of samples from the surged weds did not significantly
decrease after a aecond round of sampling while samples from
the bailed weds showed a four-fold decrease (Paul et al., 1988).
Because these wels were drilled in low permeability sediments
without added fluids, the action of drawing down the water level
within the well by being may have been sufficient to provide
adequate development. On the other hand, baMng or pumping
techniquea alone may not be effectftdn weds constructed by
driing methods that Introduoe fluids or cauee significant distur-
bance of eedknenftbecause the development ferae ie dissi-
pated by the filter pack.
The potential impacts el monitoring wed development on
ground-water sample quadty are outlined in Table 2 which ia
5
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TABLE 2. POTENTIAL MPACTS OF DEVELOPMENT METHOOS ON
GROUND-WATER SAMPLE QUALTTY
potontW Impacts
Surging with surge block
Surging and pumping
wvncomprooMoor
Pumpng md ovwr*
pumping wMi pump
!kJ|L ju
jtung wm m or nwr
Backwashing with wsior
B*ng
Displacement ol filer pack and formation
materials or damage to the wel iniaka (primarily
a problem in poorly dasignad and oonatiudad
wets whan surging is conducted improperly)
Exoeasive mobization o( line-grained mstariais
from tow-parnMbiky formations
Entrapment of air in Star pack and formation
Diaruption of hydrochemicai aquftbrium
HVOQucnMOicoiRvniim
Low-volume pumpa may be incapable o<
sufficient surging action (primariy in high-yield
wMi who mi of no onwwMTi/
Entrapment of air in Mtar pack and formation
Disruption ol hydrochemical aquNxium
Introduction ol contaminants
Exoeesius moblzaNon of fine-grained nuieriali
from lowpermeaMty formaiions
Disruption ol hydwthamfcal squMbrium
Introduction of contaminants
May ba incapafala ol sullciSNl davslopmsnl
¦cnon
baaed on th« work ol Keely and Boateng (1987), Paul at al.
(19W), Allar at al. (1989). wd Kraamar at al. (1991).
MATERIALS
Tranefar of ground water from tha aubaurfaoa sampling zona to
a sample containar at ground surface oftan involves contact of
tha sample with a variety of materials comprising tha wall,
sampling devioe. tubing, and container. Soma of thasa mated-
ala have tha potantiai to bias chemical oonoantratlona in
sampiee as a raault of sorption. leaching. and chemical Hack,
and biological activity (Barcelona at al.. 1983). As a result, tha
matarials aalactad for ground-water sampling must ba appropri-
ate for tha hydrochamical conditions at tha slta and the constitu-
ents baing aampiad. Other factors that may influence the choice
of materials, including costs verses benefits, availability,
strength, and ease of handling, can ba found in Allar at al.
(1989).
Materials commonly used in the ground-water sampling train
can be divided into five general categories (modified from
Nielsen and Schalla. 1991):
1. fluoropolymers, which include polytetrafluoroethylene
(PTFE), tetrafluoroethylene (TFE), andfluorinated ethylene
propylene (FEP);
2. thermoplastics, which include polyvinyl chloride (PVC),
acrylonitrile butadiene styrene (ABS), polypropylene (PP).
and polyethylene (PE);
3. metals, which include stainless steel (SS), carbon steel,
and galvanized steel;
4. silicones; and
5. fiberglass-reinforced, which include fiberglass-reinforced
epoxy (FRE) and fiberglass-reinforced plastic (FRP);
This document will focus on the most commonly used materiala
including tha rigid materials PTFE, PVC, and metals (particularly
SS) and the f lexfcie materials PE, PP, PTFE, PVC, and silicon*.
Clwmlcal and Biological Impact*
Sorption, which includes the processes of adsorption and ab-
sorption, may remove chemical constituents from sampiee
thereby reducing the concentrations of these constituents from
levels present in the ambient ground watar. H compounda
present in the ground watar are removed entirely, falsa negative
analytical results wiN be produced. Additionally, deeerptbn ol
compounda previously sorbed can occur If watar moving past
the material contains lower concentrations of the sorbant than
exists in the material. In this case, contaminants may ba
detected in samples that do not exist in the ground watar,
causing falae positive analytical raeuks. SorptiorVdesorption
processes may be particularly important in situations where
contaminant concentrations are at trace levels and changawM*>
time or where samples contact potentially eorbing materials for
long periode (for example, during water level recovery in low-
yield wells or in inadequately purged weds).
Leaching of chemical constituents from some types of materiala
may occur under the conditions present at many hazardous
waste sites. Constituents of the materials' matrix, or compounds
added during fabrication, storage, and shipment, may hava
aoHjbiWee in watar high enough to be leached under natural
ground-watar conditions (GiHham at al., 1983). Ground water
contaminated by high concentrations of organic solvents may
cause significant degradation of the matrix of some polymeric
materials, resulting in leaching of varioua compounda
(Barcelona et ai., 1983). As a rasult. falsa positive analytical
reaults can ba produced if tha aource of target constkuentrtn
ground-watar sampiee is leaeffing f ram casing materiala NflMr
than tha ambient ground water, in addition, corrosion ol metal
casing may introduce diasoived metals to ground-watar
samples and reduce the integrity of the well.
Under oartaln ground-water conditions, wad-casing materiala
may Impact bidfcglc activity, and vice versa. In the vicinity of the
wel (Barcelona et al., 1988b) and lead to errors that are dilfipwk
to predict. For example, the presence of dissolved iron In
ground-water may favor the growth of iron bacteria near mataie
weds and degrade the casing and screen (Driscoll,1986). In
addition, permeation of contaminants or gases through mated-
-------
al* may be a potential sourca of sample biaa with flexibla tubing
(Barker at al., 1987; Holm, 1988) but is unlikaly with rigid
matariala, as damonstratad by Berens (1985) for organic com-
pounds and rigid PVC pipa ovar tima periods lass than 100
yaars.
Rigid Material*
Rigid matariala that contact ground-watar samplas ara ganarally
usad in wall casings and scraans, sampler componants, and
filtration equipment.
PTFE
PTFE haa baan widaly considered tha bast choica for monitoring
wall matariala bacausa of Its apparent resistance to chemical
attack and low sorption and teaching potential. However,
several recent laboratory studiea have shown that rigid PTFE
materials actually demonstrate a significant ability to sorb hydro-
carbons from solution. Sykes at al. (1986) found that PTFE
matariala sorbed several hydrocarbons from a solution contain-
ing concentrations of approximately 100 |ig/L, but did not report
quantities. Parker et al. (1990) found that rigid PTFE materials
sorbed significant quantities of all tasted chlorinated organics
and a nitroaromatlc; higher, in fact, than PVC matariala. These
workers found that losses of some of these compounds from test
solutions (initial concentrations of each compound were ap-
proximately 2 mg/L) exceeded 10% within eight hours, like-
wise, rigid PTFE materials showed significant sorption of aro-
matic hydrocarbons in 24 hours of exposure for benzene, and
six hours for several other hydrocarbons (Gillham and
O'Hannesin, 1990). After eight weeks of PTFE exposure to
benzene, 75% losses from the test solution were observed.
In contrast, PTFE materials tend to show lower potential for
interaction with trace metals than PVC or SS (Barcelona and
Helfrich, 1986). For example, lead was the only metal of four
tested (arsenic, chromium, cadmium, and lead) in a laboratory
study to be actively sorbed onto PTFE materials although only
5% of tha lead concentration in the tost solution was removed
after 24 hours of exposure (Parker et al., 1990).
PVC
Early studiea of PVC materials found substantial potential for
sample error from sorption and leaching effects. Many of tha
conclusions about sorption were based on flexible PVC, which
has a much higher sorption potential than rigid PVC. Leaching
of high VOC concentrations was found to be a particular problem
from PVC solvents and cements used for casing Joints and bailer
construction. Boettner et aL (1961) found cydohexanone,
methylethytketone, and tetrahydrofuran leached Into water at
concentrations ranging from 10 ng/L to 10 mg/L for more than 14
days after the glue was applied to PVC pipa. In addition to these
compounds, methylisobutyketone was detected in ground-
water samples several months after the installation of cemented
PVC easing (SosebeeetaL (1982). The results of these studies
Indicate that alternative methods of Joining PVC easing, such as
threaded joints, should be utilized to reduce sample error.
Laboratory investigations show that threaded PVC well materi-
als sorb hydrocarbon compounds, but often at lower rates than
other polymers, including PTFE. Miller (1982) found little
absorption of six VOCs over a six-week period, with the excep-
tion of tetrachlorethylene which showed a 50% decline in
concentration in solution. These sorption results were signifi-
cantly lower than those from PE and PP casing materials.
Subsequent leaching from PVC was found to be at insignificant
levels for all six VOCs. Gillham and O'Hannesin (1990) found
that significant sorption ontc rigid PVC from a solution contain-
ing six hydrocarbons did not occur until 12 hours after exposure.
The PVC results were in contrast to three other rigid polymers
(PTFE, FEP, and polyvinylfloride) that showed significant up-
take of at least one of the six compounds within three hours of
exposure. After eight weeks of PVC exposure to benzene, 25%
losses were observed from the original solution concentration of
approximately 1.2 mg/L. Similar results were reported by Parker
et al. (1990) who found that PVC sorption of 10% of initial organic
compound concentrations didnl occur until over 72 hours of
exposure, while PTFE sorption of 10% of three of the 10 tested
organics occurred within eight hours of exposure. Two dichb-
robenzene isomers showed the highest sorption rates on PVC:
significant losses were observed within eight hours. Sykes et al.
(1986) found no significant differences between PVC, PTFE.
and SS materials in their tendency to sorb six organics at
concentrations of approximately 100 }ig/L each.
The results of these research studies indicate that rigid PVC
materials have relatively low potential for sorption and leaching
of organic compounds relative to other polymers when exposed
to dissolved concentrations generally found at hazardous waste
sites. However. Berens (1985) demonstrated that PVC may
soften and allow permeation of organic compounds if exposed
to nearly undiluted solvents or swelling agents for PVC. For this
reason, PVC well casing should be avoided under these
conditions.
PVC materials may also react with some trace metals. Miller
(1982) concluded that in a six-week exposure to test solution,
PVC materials did not affect chromium concentrations but that
lead concentrations declined over 75%. A subsequent experi-
ment showed that over 75% of the initial lead concentrationa
were desorbed from the PVC material. Parker et ai. (1990)
found that rigid PVC showed no measurable sorption or leaching
of arsenic or chromium but that cadmium was leached and lead
sorbed. For example, sorption of lead resulted in a 10% decline
in lead concentration in their test solution in four hours, while
subsequent desorption resulted in a 10% increase in lead
concentration after four hours.
Stainless Steel
SS casing materials are often used when conditions warrant a
strong, durable, corrosion-resistant material. Of the two types
available, Type 316 is somewhat less Ntely than type 304 to be
affected by pitting and corrosion caused by organic acids,
sulfuric add, and sufur-containing species (Barcelona et al..
1983). However, long exposure to very oorrosive conditions
may result In chromium and nickel contamination (Barcelona et
aL, 1963), or iron, manganese, and chromium contamination
(U.3. EPA, 1967) of samples. A field study by Barcelona and
Helfrich (1986) found thai stagnant water samples from SS
installations showed higher levels of ferrous iron and lower
levels of dissolved sulfide than nearby PTFE and PVC wells,
suggesting leaching from the SS and precipitation of sulfide by
the excess iron. However, these workers demonstrated that
7
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proper wall-purging techniques eliminated this stagnant water
from ground-water samples, providing representative ground-
water samples.
Laboratory experiments conducted by Parker et al. (1990)
examined the potential for sorption on type 304 and 316 SS
casing materials. These workers conducted experiments with
aqueous solutions of arsenic, cadmium, chromium, and lead at
concentrations of 50 ^ig/L and 100 jig/L and found that after 10
hours, sorption on both type 304 and type 316 caused a 10%
decline in arsenic concentration in the test solution. Cadmium
concentrations increased 10% in five hours due to leaching from
type 304, before returning to initial concentrations after 72
hours. Cadmium leaching from type 316 caused a maximum
30% increase after 20 hours, with concentrations still 20%
above initial values after 72 hours. No measurable sorption of
chromium occurred for type 304, but 13% losses in 13 hours
were observed for type 316. Sorption of lead on type 304
materials led to 20% losses after only four hours of exposure,
and approximately 10% for type 316. Parker et al. (1990)
concluded from this work that determinations of the concentra-
tions of cadmium, chromium, and lead may be impacted by long-
term contact with stainless steel materials. Unfortunately, these
workers did not address whether well purging would eliminate
these impacts and provide representative ground-water
samples.
In a study with five halogenated hydrocarbons, Reynolds et al.
(1990) found type 316 SS caused losses of bromoform and
hexachtoroethane over a five week period. Losses of these
compounds from the teat solution were insignificant until one
week, after which concentrations dropped up to 70% from initial
concentrations of 20 to 45 ygA.. The losses were attributed to
reactions involving the metal surfaces or metal ions released
from the surfaces and not to sorption (Reynolds et al.. 1990). A
study by Parker et al. (1990) with ten organic compounds at
concentrations of approximately 2 mg/L, found that type304and
type 316 SS casing resulted in no detectable sorption or leach-
ing effects after six week*.
Other Metallic Materials
Steel materials other than stainless steel may be more resistant
to attack from organic solutions than polymers, but corrosion is
a significant problem, particularly in high dissolved-soWs, acidic
enwonments (Barcelona et al., 1985a). Ferrous materials may
adsorb dissolved chemical constituents or leach ions or corro-
sion products such as oxides of iron and manganese (Barcelona
etal., 1988a). In addition, galvanized steel may contribute zinc
and cadmium species to ground-water samples. The weath-
ered steel surfaces, as vm as the sold corrosion products
themselves, increase the surface area for sorption processee
and may therefore act aa a source of bias for both organic and
inorganicconstituents (Barcelona etal., 1988a; Barcelona etal.,
1983). Reynolds at aL (1990) determined thai galvanized steel
showed a 99% reduction in concentrations 61 five halogenated
hydrocarbons in a fiws week sampling parted. Aluminum casing
caused concentration reductions of 90% for four of the com-
pounds. Although many of theee aspects of steel materials have
not been quantified for typical grourtd-water environments, they
may be a significant souros of sample error.
Alternate Materials
Although not as widely tested or used, FRE may represent a rigid
well material with relatively low potential for sample bias. In a 72.
hour laboratory study, none of the 129 priority pollutants wer*
detected to be leached from a powdered sample of the material
(Cowgill, 1988). A three-week dwell-time study of casing
materials by the same investigator resulted in detection of no
base/neutral or acid compounds. Gillham and O'Hannesin
(1990) concluded that sorption of benzene and other aromatic
hydrocarbons onto FRE was slightly greater than onto rigid PVC
but less than onto PTFE.
Borosilicate glass, another little-used well material, revealed no
sorption effects alter a 34-day exposure to five halogenated
hydrocarbons (Reynolds et al.. 1990). Of the ten well materials
tested in that study, only the borosilicate glass showed no
sorption characteristics. The low potential for sample error
indicated by that study suggests that further investigation of
borosilicate glass may be warranted to determine its suitability
for ground-water sampling.
FI§xlbi0 Material*
Semi-rigid and f lexble materials are used for transfer tubing and
other flexible components of the sampling/analysis train. In
general, these materials contain plasticizers for flexibility that
give them a higher potential than rigid materials to sorb or leach
compounds. Latex rubber tubing, flexible PVC, and low density
PE were al found to sorb greater quantities than more rigid
materials (Reynolds et al.. 1990).
In a study of five tubing materials in solutions of four chlorinated
hydrocarbons, Barcelona et al. (1985b) found that most sorption
occurred in the first 20 minutes of exposure. With the exception
of tetrachloroethylene, the materials ranked in order of increas-
ing sorption PTFE. PP, PE. PVC. and siiioone. PE ihnnedlha,.
highest sorption of tetrachloroethylene. Desorption from al
materials occurred rapidly with the same ranking: PTFE dee-
orbed a maximum of 13% of the sorbed concentrations after one
hour while silicone desorbetf?%. From the results of this work,
Barcelona et al. (1985b) estimated sorptive losses of chlori-
nated hydrocarbons from sampling tubing under typical flow
rates. As an example, using 15 m of 1/2-inch tubing, initial
concentrations of 400 tig/L for the four halocarbons, and a
sample delivery rate of 100 mUmin. these workers predicted 21,
29,48.67. and 74% sorptive losses for PTFE, PP, PE. PVC. and
silicone tubing, respectively.
Sorption tests conducted by Barker et al. (1987) found that
flexible PTFE led to 17% sorptive losses of benzene and 58%
losses of p-xylsne after two weeks. For PE, 49% ioeserel
benzene end 91% losses of p-xyiene were obeervad in-MO
weeks. As found in other studiee, initial rapid losses wsra
followed by gradual concentration declines in all compounds.
Desorption of theee compounds folowed a similar pattern,
approximately 40% of the initial benzene mass and 20% of the
initial p-xylene masses desortoed. Laboratory tests conducts*
by Giham an*O'Hannesin (1990) showed PVC and PE tubing
caused sorptive losses of over 10% within five minutes*
exposure to six hydrocarbons in solution. After 24 hours, 98*
losses for the PVC and 80% losses for the PE had occurred.
8
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These studies suggest that flexible PTFE tubing has lower
potential for sorption and leaching than other materials, particu-
larly PVC and silicone. However, even PTFE tubing may have
significant impacts on concentrations of organic compounds in
ground-water samples, depending on duration of contact. It is
dear that the sorption and leaching affects of all materials used
as tubing or other flexble portions of the sampling/analysis train
should be considered when designing the sampling program.
Those materials that demonstrate high potential for sorption
and/or leaching should be avoided if those processes could
impact concentrations of the compounds of interest to the
investigation.
A further source of sample bias with respect to tubing is
transmission of compounds or gases through the tubing mate-
rials. In a study of PE and PTFE, Barker et al. (1987) detected
2 jig/L benzene and 15 ng/L toluene passing through PE tubing
within three days and 15 |ig/L and 100 tig/L, respectively, after
six days. Subsequent flushing of the tubing with three tubing
volumes of clean water reduced the concentrations of both
oompounds detectable inside the tubing but they were still
detectable after twenty volumes were flushed. Under the same
conditions, the compounds did not pass through the PTFE
tubing in detectable concentrations. These workers suggest
that this mechanism may lead to sample bias in other polymeric
materials, although perhaps at rates somewhat less than those
exhibited by the flexble PE tubing, and could influence conclu-
sions about when well purging procedures or remediation activi-
ties are complete. Holm et al. (1988) studied the diffusion of
gases through FEP tubing, and found that the amount of gas
transferred is proportional to the tubing length and inversely
proportional to the flow rate through the tube. Calculations by
the authors suggest that, given initially anoxic ground water,
oxygen diffusion through sampling tubing could lead to detec-
tion of DO and changes in iron speciation within tens of feet. The
results of these studies dearly indicate the potential errors that
transmission through flexible tubing might introduce when sam-
pling for both organic and inorganic compounds. This source of
error can be reduced by using appropriate tubing materials for
the sampling conditions and by minimizing tubing lengths.
S4*ctk>n of MatorlMlM
It is clear from laboratory studies of casing materials that
concentrations of trace metals and hydrocarbons can be im-
pacted by sorption and leaching from PTFE, PVC, and metallic
casing materials. However, laboratory studies do not attempt to
duplicate the complicated, interrelated physical, chemical, and
biologic conditions present in the field that may cause materials
to behave very differently in the hydrogeotogic environment It
is also important to keep In mind that most of these experiments
were conducted under static conditions and may not adequately
represent field conditions where stagnant water is generally
replaced with fresh ground water during well purging. In the
field, sorption of compounds onto casing materials between
sampling events may not affect subsequent ground-water
samples, as long as adsquate purging andsampingprooedures
are conducted. Desorption of previously sorted compounds
after long-term exposure may be of somewhat greater impor-
tance because continuous desorption may impact trace-level
concentrations, which might have important implications to
remedial investigations where concentrations are expeded to
eventually reach non-detectabie levels. But again, proper
selection and implementation of materials and purging and
sampling methods will reduce the impad of these processes.
Given the above discussion and current state of research, some
generalizations may be made about the applicability of casing
materials to various ground-water contamination scenarios,
assuming that reducing sample error is the primary criterion for
selection. When monitoring for low hydrocarbon concentrations
in non-corrosive ground water, SS and PVC casing may be
appropriate choices. Because PTFE has been shown to intro-
duce error into hydrocarbon determinations, it may be most
applicable under conditions where SS and PVC are not. As
examples, SS would not be appropriate in corrosive ground
water or where determination of trace metal concentrations is of
primary concern and PVC wells would be inappropriate in
situations where solvents in moderate to high concentrations
could dissolve the PVC material. A summary d the properties
d rigid PVC, PTFE, and SS materials that may introduce sample
error is shown in Table 3.
Laboratory studies indicate that the potential for error from
flexible tubing is much greater than from rigid materials. For this
reason, efforts should be made to use tubing with low potential
for sorption and leaching and to minimize tubing length and time
d contact It appears that sample error can be significantly
reduced by substituting flexible PTFE for PVC and silicone
where possible.
MONITORING WELL PURGING
Purging stagnant water from monitoring wells prior to sampling
is considered essential to collection d samples representative
d ambient ground water. Stagnant water may result from
biological, chemical and physical processes occurring between
sampling events. These processes may include biological
activity, sorption/desorption reactions with materials of the well,
leaching from the materials d the wed, degassing and volatiliza-
tion, atmospheric contamination, and foreign material entering
the well from ground surface.
An effective purging method must allow for flushing of the well
and sampling device d stagnant water without causing undesir-
able physical and chemical changes in the adjacent water-
bearing zone that may bias subeequent samples. Important
aspects d purging indude purge volume, pumping rate, depth
d the purging device, and purging methods for low-yield wells.
Field experiments have shown that purging has important
impacts on sample chemistry, perhaps greater than other as-
pects d sampling protocol such as sampling device and mate-
rials (Barcelona and HeNrich, 1986).
Purg9 Volume
To ensure oomplete purging d a ground-water monitoring well,
there must be established criteria to determine when the water
in the wel is representative d ambient ground water. Three
criteria commonly advocated to determine appropriate purge
votume have been d n arih sd by Gtos and Imbrigiotta (1990) as:
(1) a specific, predetermined number d weM-bore volumes. (2)
stabilization of the values d field chemical indicator parameters
(such as temperature, pH, and EC), and (3) hydraulic equilib-
rium between water stored in the casing and water entering the
casing.
9
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TABLE 1 PROPERTIES OF COMMONLY-USED WELL CASINO
MATERIALS THAT MAY IMPACT GROUND-WATER SAMPLE QUALITY
Material
PropartlM
Polytetrafluoroethylene Moderate potential for sorption of hydrocarbons.
(PTFE)
Low potential tor leaching of organic constituents.
Some potential for sorption and IsacNng of
metais, but leaa than with thermoplastic and
metaNc materials.
Particularly reeistant to chemical attack, including
aggressive acids and organic solvents.
Not sublet to corrosion.
Resident ^ Tfff*
Stainless Steel (SS) Very low potential for sorption of hydrocarbons.
Not subject to leaching of organic constituents.
Significant potantial lor sorption and leaching of
matals.
Subject to chemical attack by organic acids and
suHur-containina suedes.
Subject to oorroeion.
Subject to biologiatf attack.
Poiyvinytehloride(PVC) Potential for sorption of hydrocarbons, but may
be leas fan with fluoropolymers.
Leaching ol organic constituents may occur
through chemical degradation by organic
advents.
ompouii via menmg ov tomo imiw.
Subject to chemical attack by organic sofcerts.
Not subject to corrosion.
The um of a specific number of well-bore volumM as the sol*
criterion for purge volume hat been applied axtanaively in
ground-water sampling with recommendations in regulations
and the literature ranging from less than one to over 20 (Herzog
et al., 1991). In addition, definitions of well-bore volume have
included the volume contained within the casing, that volume
plus the pore volume of the filter pack, and the volume of the
entire borehole. Despite its widespread use, the well-bore
volume approach does not directly address the issue of obtain-
ing representative ground water because there is no proven
relation between the number of well volumes removed and th«
completion of purging. The combination of details of w&ii
construction, contaminant distribution, and geologic and
hydrochemical conditions result in unique conditions at everC
well such that the volume of water required for purging cannot
be determined a priori. It is impossible to predict the magnitude
of error that might be introduced by arbitrarily choosing ?
number of well volumes that results in incomplete purging.
Determining purge volume by measuring field parameters
also widely used. The assumptions implied in this approach *rZ
that; (1) as these parameters stabilize, stagnant water in the vve.ii
has been replaced by ambient ground water, and (2) this wat«r
contains representative concentrations of the compounds of
interest. However, field experiments conducted by Gibs aiv!
Imbrigiotta (1990) showed that field parameters often stabilize
before the concentrations of VOCs. In almost 90% of th«j,
experiments, field parameter measurements stabilized when
three well casing volumes had been purged while VOC concori
trations stabilized after three well volumes in only about half ni
the cases. Likewise, Pearsall and Eckhardt (1987)observed in
a series of field experiments that trichloioethylene concentra
tions continued to change after three hours of pumping at 1 9 7/
min while field parameters stabilized within 30 minutes. Further-
more, measurements of individual field parameters may m
reach stable values at the same purge volume suggesting th*
some perameters are more sensitive to purging than others. Par
example, Pionke and Urban (1987) found that temperature, dH.
and EC values of purge water from 14 wells studied generajk)
stabilized before dissolved oxygen and nitrate concentration?
Puis et al. (1990) found that while temperature, pH, and EC
values generally stabilized in less than a single well-bore vol-
ume, other Indicators such as dissolved oxygen and turbidity
required up to three well-bore volumes before stabilization.
et al. (1990) considered reduction of turbidity to stable values
using low pumping rates as critical to the collection of repress
tative metals samples. It should be pointed out that in
cases mentioned above, reliance on commonly measured^
rameters (temperature, pH, and EC) alone would apparent
have underestimated the proper purge volume. These results
suggest that the choice of purge indicator parameters should be
made such that the indicators are sensitive to the puig|m
process and relate to the hydrochemicai constituents of inter**!
This can be accomplished by evaluating the patterns of indicator
parameters and ground-water constituents during well puitaim
(a purge-volume test) to determine the appropriate puma
volume.
Another implied assumption of the field parameter approach is
that purging will result in the stabilization of all constituent
concentrations at approximately the same purge volume, in
many hydrogeotogic systems this assumption may not be v^id.
For example, in aquifers corftamiritted by several VOCs, con-
centration trends during pumping may be very different. In
evaluation of a purge-volume test, Smith et al. (1988) found that
concentrations of two compounds started relatively high and
decreased with purging to below detectable levels. Two other
compounds that were undetected at three casing volumes vwoie
detected at tour casing volumes and their concentrations in-
creased until stabilizing at ten casing volumes. A fifth compound
remained at a constant concentration throughout the puna-
volume test. The authors did not report the concentrations
observed orthe volumes pumped, but it is clearthat under those
10
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conditions the choice of purging volume could significantly
impact interpretations of contaminant concentrations.
K is important to keep in mind that the distribution of contami-
nants in limited plumes within a ground-water system is gener-
ally in contrast to the more homogeneous distribution of natural
hydrochemical conditions in space and time. Consequently,
attaining stable concentrations of field parameters, or even
gross chem istry, may not indicate a representative sample of the
targeted aquifer volume around a monitoring well (Keely and
Boateng, 1987). As a result, these workers suggest that the
'inherent variability of the concentration of contaminants in
many plumes far outstrip the additional variability potentially
induced by incomplete purging,' and recommend that spatial
and temporal variations in contaminant concentrations be stud-
ied to determine optimum purge volumes.
Methods of determining purge volume by estimating when
hydraulic equilibrium occurs between water stored in the casing
and water entering the casing may be useful where conserva-
tive, non-varying constituents are being monitored. However,
determining hydraulic equilibrium by estimating the time at
which water levels in the well are no longer affected by casing
storage (the method of Papadopubs and Cooper, 1967) may
lead to erroneous results (Gibe and lmbrigbtta.1990). These
workers compared the calculated hydraulic equilibrium volume
to measurements of field parameters and VOC concentrations
during several well purging experiments and found that the
calculated volume consistently underestimated the volumes
required to reach both stable field measurements and stable
VOC concentrations. The casing storage method might provide
an approximation of purge volume under conditions where
conservative, non-varying constituents are being monitored but
the available evidence suggests that only sampling for the
constituents of interest will provide a direct indication of when
their concentrations stabilize.
Recent research reviewed by Puis et al. (1990) demonstrates
that oontaminants may be transported in ground water by
association with colloidal-sized partides which are generally
described as particles less than 10 nm in diameter. Where
contaminant transport by association with colloids is an impor-
tant mechanism, obtaining representative concentrations of
mobile colloids becomes critical to sample representativeness.
However, the acts of purging, sampling, and even placing the
sampling device in the well have been demonstrated to signifi-
cantly impact colloidal suspension in the sampling zones of
monitoring wells (Puis et al., 1991; Kearie et al., 1992). If a
significant portion of contaminants are transported in associa-
tion with colloids, the results of these investigations and others
suggest minimizing or eliminating purging, minimizing sampling
flow rates (100 to 500 mL/min), and using dedicated sampling
devices placed within the wed intake may all be necessary to
ooflect representative ground water samples. This low-volume
approach to purging and sampling was earlier proposed by
Robin and Gillham (1987) when sampling for conservative, non-
varying parameters in high-yield weds. Using non-reactive
tracers, these workers demonstrated that natural ground water
movement through the well intake was sufficient to prevent the
formation of stagnant water with respect to conservative, non-
varying parameters, making purging large volumes unneces-
sary. Robin and Gillham (1987) pointed out that, under these
hydraulic and hydrochemical conditions, representative
samples can be collected with little or no purging using dedi-
cated devices positioned within the well intake, in order to
resolve the issue of low-volume purging, however, it appears
that more research is necessary to better understand colloid
movement in ground-water environments, their importance to
contaminant transport, and their implications to purging and
sampling techniques.
Purg§ Rata and Dapth
It was suggested previously that the pumping rate at which
purging is conducted may impact sampling results. Although
few detailed studies have been conducted to directly address
this issue, the results of a few specific field studies suggest the
types of impacts that purging rates might have on sampling
results. For example. Imbrigiotta et al. (1988) reported that
purging rates of 40 l/min were found to produce VOC concen-
trations up to 40% higher than concentrations obtained at
purging rates of 1 L/min. Likewise, purging with a high-speed
submerstole pump at a rate of 30 L/min was found to generally
produce higher colloid concentrations and larger particle sizes
than a low-speed pump at rates lower than 4 Umin (Puis et al.,
1990). Despite these colloid differences, however, metals and
cation concentrations did not necessarily correlate to pumping
rate. Both investigators attributed the variability to the effects
that different pumping rates had on the distribution of
hydrochemical conditions near the well. Imbrigiotta et al. (1988)
further concluded that the variability in VOC concentrations
caused by purging rate was of the same magnitude as that
observed in a comparison of seven types of sampling devices,
suggesting that purging rate may be at least as important to the
collection of representative samples as the type of device
utilized. Puis et al. (1990) suggested that the colloid differences
might also have resulted from entrapment of normally non-
mobile suspended particulates in the wells.
Although the issue remains unresolved, it appears that employ-
ing pumping rates that allow sample collection with minimal
disturbance of the sample and the hydrochemical environment
in and nearthe well may aid in minimizing sampling error. To this
end, it has been suggested that the purging rate be chosen such
that the rate of ground water entering the well intake is not
significantly higher than the ambient ground-water flow rate
(Puis and Barcelona, 1989). Undertypical hydraulic conditions,
this may be possible with pumping rates between 100 and 500
mL/min.
The depth at which purging is conducted may also affect sample
representativeness. At high pumping rates or in low- and
medium-yield wells, purging at depths far below the air-water
interface may introduce error because stagnant water from the
well above the pump may be drawn into the pump inlet Under
these conditions, pumping near the air-water interface signifi-
cantly reduces the time required to remove stagnant water by
reducing mixing from above the pump intake (Unwin and
Huis,1983; Robin and Gillham, 1987). Keely and Boateng
(1987) suggest lowering the pump during purging so as to
further reduce the possibility of migration of stagnant water into
the intake during sample collection. On the other hand, under
high-yield conditions, placing the pump at the well intake and
utilizing low pumping rates may serve to isolate the stagnant
water in the well bore above the pump thereby providing
representative samples with minimal purging (Barcelona et al.,
11
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1985; Robin and Gillham. 1967). Unwin and Maltby (1988)
reported that pumping at virtually any depth within a wall,
including tha intaka, may laad to contamination of samples by
stagnant water from abova tha pump inlat although thair labora-
tory invastigation demonstrated that at a pumping rata of 1 \j
min, samples collactad within tha wall intaka containad lass
stagnant watar than samples collactad abova tha wall intaka.
Regard lass of tha dapth of tha pumping davica, if a stagnant
watar zona davalops near tha watar surfaca subsaquant move-
ment of tha pump or placamant of a sampling davica through this
zona may causa contamination of tha davica by stagnant watar.
As suggested abova in tha discussion of purge volume, certain
hydrogeologic conditions and chemical constituents may re-
quire that samplas be collactad with littla or no purging using
dedicated davices positioned within tha wall intaka. Underthese
circumstances, it would also ba necessary to utilize low purging
and sampling rates so as to minimize disturbance of tha sample
and sampling environment and to prevent migration of stagnant
water from the well bore down into the sampler intake.
Purging In Low-Yield Weilt
Purging low-yield wells introduces conditions that by definition
don't occur in medium- to high-yield wells. These conditions,
which tend to have their greatest impact on constituents that are
sensitive to pressure changes and/or exposure to construction
materials or the atmosphere, often result from dewatering the
filter peck and well intake. Dewatering may produce a large
hydraulic gradient between the adjacent water-bearing zone
and the filter pack as a result of the large drawdown in the well
and the low hydrauHc conductivity of the formation. One
consequence of this condition may be the formation of a seep-
age face at the borehole wall causing ground water entering the
borehole to flow down the borehole wall and fill the dewatered
filter pack (rem the bottom up. Formation of a seepage face
increases the surface area of the interface between the liquid
phase (ground water) and vapor phase (headspace in the well)
available for transfer of solutes. Another consequence of the
large hydraulic gradient is the sudden pressure decline from the
pressure head in the water-bearing zone to atmospheric pres-
sure in the pumped well. The sudden release of this pressure
may cause losses from solution (by degassing or volatilization)
of solutes that have combined partial pressures, with that of
water, greater than atmospheric. Finafly.because water levels
recover slowly in low-yield weds, significant changes in the
chemical composition of the ground water may occur through
sorption, leaching, or volatilization before sufficient volume is
available for sample collection.
In a field study of purging and sampling in tow-yield wells,
Herzog at al. (1988) found that some VOC concentrations
increased significantly from pre-purging conditions during the
first two hours of water level recovery, for example, chloroben-
zene concentrations increased from 25 ugA. before purging to
over 125 pg/1. at two hours after purging. Concentrations
generally did not change significantly after two hours, although
some concentrations declined. Although Herzog (1888) pro-
vided no explanation for tha observed concentration trends,
they were fikely caused by more representative ground water
entering the well and replacing the purged stagnant water.
Smith et al. (1988) reported very different results in their field
study of a trichloroethylene plume. Concentrations of trichloro-
ethylane declined from 100 ng/L directly after purging to 10 p.g/
L 24 hours after purging. In a laboratory study, McAlary and
Barker (1987) found that if tha water level in a simulated well was
drawn down balow tha intaka, VOC concentrations during
recovery declined 10% in five minutes and 70% in one hour.
These changes were attributed to volatilization from the water as
it entered and filled the well.
In summary, aspects of well purging important to collection of
representative samples include purging volume, pumping rate,
depth of the purging device, and time of sampling in low-yield
wells. Although error is strictly dependant on individual wall and
site conditions, the available evidence suggests that order-of-
magnitude errors may easily result from improper purging
techniques. In low-yield wells, time of sampling is clearly an
important source of error although there are too few data
available to completely understand concentration trends in
these situations.
Contamination concentrations during purging vary in ways that
are often difficult to predict, and various compounds may even
exhibit opposite trends. To estimate the appropriate purga
volume, it may be necessary to conduct preliminary purge-
volume tests with sampling at regular intervals during purging.
These tests may be useful for determining how indicator param-
eters and constituent concentrations respond to purging rates,
purging volumes, and the distribution of contaminants around
the well. In addition, for certain sensitive constituents such as
trace metals under certain hydrogeologic and hydrochemical
conditions, low-volume purging and sampling should be consid-
ered with dedicated sampling devices installed at the well intake.
SAMPLE COLLECTION
Sample collection involves physical removal and transport of
ground water from depth (generally from a monitoring well) to
ground surface and into a sample container. As such, collection
methods may have great potential for alteration of the samplers,
chemical state. Sampling devices must be chosen and used
carefully to ensure that error is minimized. Important aspects ol
sample collection include sampling device, collection time alter
purging, and sampling depth.
Chemical knpactt
Sampling devices can cause chemical changes in the sample by
contact with materials of the device (sorption, desorptton. or
leaching) or by the physical action of the device. Although the
materials of the device are a potentially significant source of
sample error, that topic was discussed previously and the
following discussion wiH address chemical changes produced
only by the operation of the sampling device.
Because fluid pressure in the saturated zone is greater thwi
atmospheric, ground-water samplee brought to the surface wM
tend to be under higher pressure conditions than the ambient
atmosphere. Exposure of these samples to the tower atmo-
spheric pressure will cause degassing and/or loss of volatle
constituents until the partial pressures of the contained volatile
components roaches equilibrium with atmospheric pressure.
Degassing may cause tosses of oxygen (Ot), methane (CHJ,
nitrogen (Nt), or carbon dioxide (CO J, while volatilization might
affect any solute that exiete as a liquid, solid, or gas under in situ
12
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ground-water temperature and pressure conditions (Gillham et
al.. 1983). Furthermore, loss of CO, may raise the pH which can
lead to precipitation of dissolved constituents, particularly iron
(Gibbet al., 1981). Constrictions in the flow path within a device
may also raise the sample pH by changing the partial pressure
of CO, (Herzog et al., 1991).
Exposure of samples to the atmosphere, or the driving gas used
in some devices, may introduce oxygen causing oxidation of
iron, manganese, cadmium, or other species. Oxidation of
ferrous iron to ferric iron has important implications to th«
speciation and concentrations of many constituents in ground
watersamples(Herzogetal., 1991). Contaminants may also be
added to the sample by exposing it to the atmosphere or driving
gas.
Sampling Dtvlcta
Sampling devices designed for use in conventional monitoring
wells can be divided into four general types: grab, positive
displacement (no gas contact), suction lift, and gas contact
(Pohlmann and Hess, 1988). Grab samplers include open
bailers, point-source bailers, and syringe samplers. Positive
displacement samplers are usually submersible pumps such as
bladder pumps, gear-drive pumps, helical-rotor pumps, and
piston pump*. Suction lift devices include peristaltic pumps and
surface centrifugal pumps while gas contact pumps include
those devices that lift water to the surface by direct gas pressure.
Submersible centrifugal pumps, which operate on the principle
of positive displacement at low flow rates, develop a partial
vacuum at the pump impellers at higher flow rates. For this
reason, high-speed submersible centrifugal pumps without vari-
able motor speed capability should be considered as distinct
from positive displacement pumps. On the other hand, sub-
mersible centrifugal pumps are now available that can be used
in 5.1-cm (2-inch) diameter wells and that allow adjustment of
the motor speed to produce very low flow rates. If used at low
flow rates, these low-speed pump* could conceivably eliminate
the application of a partial vacuum to the sample and thereby
can be considered as positive displacement pumps. Discussion
of the operating principles of many of ground-water sampling
devices, and their potential for sample bias, can be found in
Gillham et al. (1983).
Sampling devices for conventional monitoring wells can be used
either portably or in a dedicated mode. Portable devices are
used to collect samples in more than one well and so may cause
cross-contamination between installations or sampling events if
not properly decontaminated. Dedicated devices are perma-
nently installed in a single well and are generally net removed for
cleaning between sampling events. Dedicated samplers, when
also used for well purging, may not have adequate flow control
for effective purging in large weds (high discharge rate) and
sampling (low discharge rate). Furthermore, parts of dedicated
samplers may sorb contaminants during periods of contact with
ground water between sampling events and then release them
during sample collection. Alternatively, if inappropriate materi-
als are used in the construction of dedicated samplers, contami-
nants may leach from these materials between sampling
events.
To study the effects of sampling devices on sample quality,
investigations have been conducted both in the laboratory and
in the field. Laboratory studies can provide values of absolute
sample error by testing under controlled conditions, particularly
constituent concentration. However, by their very nature, labo-
ratory experiments represent ideal conditions that can never be
duplicated in the field and therefore may not include important
field-related errors. On the other hand, field studies include all
the physical, chemical, biological, and operating conditions
present in field sampling efforts, but the true concentration of the
constituents of interest are unknown. As a result, field compari-
son studies cannot provide values of absolute sample error, only
the relative ability of individual devices to recoverthe constituent
of interest.
Values of field chemical indicator parameters can often be the
first indication of sample errors due to sampling device. Labo-
ratory investigations of a wide range of sampling devices by
Barcelona et al. (1984) revealed that pH and redox potential (Eh)
were the most sensitive to sampling device. The largest errors
were produced by a peristaltic pump (an increase of 0.05 pH
units and a 20 mV decline in Eh). All tested devices had O, and
CH^ losses of 1% to 24%, although positive displacement
devices and an open-top bailer resulted in the lowest losses and
the highest precision in that study. A field study by Schuller et
al. (1981) found that, as a result of CO. stripping, an air-lift pump
and a nitrogen-lift pump produced pH values up to 1.0 pH unit
higher than a peristaltic pump and opentop bailer. Other field
studies concluded that open-top and dual-valve bailers pro-
duced no more error in field parameter values than bladder
pumps (Houghton and Berger, 1984). In that study, which used
bladder pump values as a standard for comparison, a peristaltic
pump and a high-speed submersible centrifugal pump had
increases in pH of about 0.06 pH units and approximately 20%
declines in dissolved oxygen (DO) concentrations. A gas-driven
piston pump had an increase in DO of 8% to 36%. Temperatures
increased up to 5% in samples collected with the peristaltic and
piston pumps and 14% in samples collected with the high-speed
submersible centrifugal pump.
Most major dissolved ions are relatively stable and not greatly
affected by collection method. Schuller etal. (1981) determined
that concentrations orf calcium, chloride, fluoride, potassium,
magnesium, and sodium collected at two field sites were not
significantly affected by the choice of suction, gas-contact, or
bailer device. Dissolved metals, on the other hand, are very
sensitive to sample aeration and degassing during sampling.
Schuller et al. (1981) found that iron and zinc concentrations in
samples collected with two gas contact devices were, at most,
30% of those collected with either a peristaltic pump or a bailer.
Field studies of 18 wells with seven sampling devices by
Houghton and Berger (1984) showed significant declines in
metals concentrations for a gas contact device when compared
to positive displacement pumps, grab samplers, and a peristaltic
pump. Houghton and Berger (1984) also found that
coprecipftation of arsenic and zinc with iron led to significant
losses of these constituents in samples collected with a high-
speed submersible centrifugal pump.
Sampling device impact on VOC concentrations is of particular
importance because of the high sensitivity of these compounds
to sample aeration and degassing and the critical need for
accurate VOC data in many site investigations. Several labora-
tory experiments have shown that positive displacement de-
vices (bladder, piston, and helical-rotor pumps) and conven-
13
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tional grab samplers (op«n-top and dual-valve baiters) provide
the most accurate VOC concentrations (Barcelona et al. 1984;
Unwin, 1984; Schalla et al., 1988; Unwin and Maltby, 1988).
Although the bladder pump and bailers that Barcelona et al.
(1984) tested produced less than 3% losses in VOC concentra-
tions, these same devices produced up to 10% losses in other
studies, even under carefully-controlled conditions. Suction and
gas-contact devices tested in these studies, and a study of
peristaltic pumps by Ho (1983), resulted in 4% to 30% losses in
VOC concentrations. Of those devices that performed well, no
relation was found between sampler accuracy and VOC con-
centration over a range of 80 to 8000 jig/L (Barcelona et al.,
1984; Unwin, 1984). The devices that performed poorty, how-
ever, often revealed significant increases in error as concentra-
tion increased (Barcelona et al., 1984). From these laboratory
studies it appears that certain classes of samplers, specifically
suction and gas-contact, can lead to significant error in VOC
concentrations as a result of volatilization from the sample
during collection.
A positive relation between increased losses of VOCs from
solution with increase in Henry's law constant was predicted by
Pankow (1986) based on theoretical considerations of the
factors leading to bubble formation in water during sampling.
Physical experiments have shown a strong positive correlation
between compound volatility and Henry's law constant for a
peristaltic pump, some correlation for a helical-rotor pump, but
no correlation for a bailer and bladder pump (Unwin and Maltby,
1988). On the other hand, Barker et al. (1987) found no clear
correlation for a peristaltic pump and gas-drive sampler and
Baiker and Dickhout (1988) found no clear correlation for a
peristaltic, bladder, or Inertial-lift pump, although the range of
Henry's law constants was small. These findings suggest that
compound volatility may not be an important source of bias for
some positive displacement and grab samplers but there may
be potential for losses for samplers that impose a suction on the
sample.
et al. (1988) concluded that syringe sampler accuracy was lower
than the pumps but that precision was comparable. Other
samplers field-tested produced significant error; a peristaltic
pump and surface centrifugal pump were found by Pearsall and
Eckhardt (1987) to be less accurate, but not necessarily less
precise than the other samplers tested. Imbrigiotta et al. (1988)
found the same lor a peristaltic pump.
In ground-water environments charged with dissolved gases,
collection of accurate VOC samples can be even more problem*
atic. VOC losses of 9% to 33% were produced by a peristaltic
pump in laboratory and field studiesof water containing high CO
(laboratory study) and CH4 (field study) concentrations (Barker
and Dickhout, 1988). Losses of 13% to 20% were produced by
a bladder pump in the laboratory study, while an inertial-lift pump
produced no losses. No differences between results from these
two pumps were observed in the field. The CO, concentrations
used in the laboratory investigation were higner than under
environmental conditions, but this study nonetheless suggest*
that degassing during sample collection, even with a positive
displacement pump, can lead to significant error in VOC concen-
trations (Barker and Dickhout, 1988).
Several "in situ* devices have been developed to alleviate some
of the problems inherent to conventional monitoring wells and
sampling devices. These devices generally utilize sample
containers under reduced pressure to collect samples directly
from the water-bearing zone, without exposure to the atmo-
sphere or excessive agitation. In a field study, Pohlmann et al.
(1990) found that two types of in situ devices delivered samples
with VOC concentrations that were not significantly different
from those collected by a bladder pump in a conventional .
monitoring well.
Although the field studies outlined above cannot provide values
of absolute sample error, they do provide information on the
effectiveness of various devices under actual operating condi-
tions. The results of the laboratory studies, in conjunctoh wRR
field studies, indicate that suction pumps are very Ikety to
introduce significant error into VOC determinations.
Grabeamplers, especially bailers, are also likely to produce
errors if not operated with great care because their successful
operation is closely related to operator skill. Under oertain
conditions, for certain parameters, and if operated by skilled
personnel, bailers can produce representative samples. How-
ever, much of the research outlined here indicates that positive
displacement pumps consistently provide the lowest potential
for sample error. Appropriate application of most types of
positive displacement pumps can reduce sampling device con-
tribution to error well below the levels of some other aspects of
ground-water sampling protocol.
Many field comparisons of sampler effectiveness verify the
findings of laboratory experiments, despite the increased num-
ber of variables involved in the field studies. Investigations
involving a variety of field conditions by Muska et al. (1986),
Paarsail and Eckhardt (1987), Imbrigiotta etal. (1988), liikaia et
al. (1988), Yeskis et al. (1988), and Pohlmann et al (1990)
concluded that positive displacement devices produced the
highest VOC concentrations, and therefore introduced the least
error into VOC determinations. The accuracy of grab samplers
was more variable: some studies showed little difference
between the VOC recoveries of bailers and positive displace-
ment pumps (Muska et al. (1986); Imbrigiotta et al. (1988);
Ukaia et al. (1988)). but Imbrigiotta et al. (1987), Yeskis et al.
(1988), and Pohlmann at al. (1990) reported that bailer VOC
concentrations were significantly lower than positive displace-
ment pumps; 46% to 84% lower in the work of Yeskis et al.
(1988). Pearsali and Eckhardt (1987) found that a bailer was as
accurate as a positive displacement pump at concentrations in
the range of 76 to 79 (ig/L but recovered 12% to 15% lower
concentrations in the range 23 to 29 |tgl.
Another grab sampler, the syringe sampler, also produced The length of time between well purging and sample collection
mixed results. Muska et al. (1986) concluded that syringe may influence the representativeness of samples by exposing
sampler accuracy and precision were not significantly different ground water to the effects of atmospheric diffusion, interaction
from those of the positive displacement pumps while Imbrigiotta with well materials, and contaminant volatilization. Smith et al.
A summary of the impacts that «>me commonly-used sampling
devices have on ground-water sample quality is shown in
Table 4 which was compiled from the sources referenced in this
section and Nielsen and Yeates (1985).
Collactlon Dapth and Tkna attar Purging
14
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TABLE 4. SOME MIPACTS THAT THE OPERATING PRINCIPLES OF
GROUND-WATER SAMPUNG DEVICES MAY HAVE ON GROUND-
WATER SAMPLE QUALITY (WITH THE EXCEPTION OF GRAB
SAMPLERS, IT IS ASSUIED THAT THESE DEVICES REMAIN N THE
WELL DURING THE SAMPLING PROCESS).
Op«rating Principle Impacts
Gas Contact Contact with drive gas may causa loss of
dissolved gam and increase pH.
Contact with drive gas may volatile sensitive
solutes.
Exposure to driving gas may introduce
contaminants or oxidize sensitive constituants.
Grab Contact wWt atmoaphara during sample recovery
and Iransiar may causa loss of dissolvad gasas
and incrtass pH.
Contact with atmoaphara during sample racovaiy
and transiar may volatMze ssnslive aolutes.
Exposure to atmoaphara during ssmple racovary
and Iransiar may introduca contaminants or
oxidbe sansitiva constituents.
May be contaminilad whan passing through
zone ol stagnant water.
PoaMve Displacement Minimai X discharge r*e is low.
Suction Ut Applcationof suction to sampls may causa loss
of dieeofved gasas and incraaaa pH.
Application of suction to sample may votatize
ssnaifcesolulss.
HKgh-Spaad Suction applsdai pump Mate may causa loss
Submsrsfcle Centrifugal oldbsdvad gasas and incraasapH.
Suction appiad at pump Mate may causa
voMMutionotsansitivasolulss.
Appictfion of sxcaaafcs haad to «w sampia may
cause dsgasslng or vulalBitfon.
Haat preduoad by pump motor may incraasa
sampls tsmpsralure.
(1988) found that trichlofoethane ooncarrtrationa in a well (to-
dined from 170 |ig/L immadiataly after purging to 10 pg/L 24
hour* later. To ansura oonsistancy and to reduce potential
error* when sampling in high-yield weds, it it generally recom-
mended that samples be collected immediately following
completion of well bore purging. In low-yield wells, however, low
water level recovery rates may require that sampling be delayed
until sufficient volume is available. Determination of sample
collection time in low-yield wells is more problematic and may
require site-specific sampling experiments.
To reduce potential errors caused by mixing with stagnant well
water during sampling, research has suggested that the sam-
pler intake be located either within the screened interval
(Giddings, 1983; Btyden et al., 1986; Robin and Gillham, 1987)
or at the top of the screened interval (Unwin, 1982; Barcelona
and Half rich, 1986) so samples can be obtained soon after fresh
ground water enters the well bore. However, in cases where
wells are screened over a long interval, it is important to
determine if contaminants are vertically stratified in the well.
Pearsail and Eckhardt (1987) found that TCE concentrations of
samples collected at the top of a 10-foot screened interval were
30% lower than those collected at the bottom and attributed the
difference to vertical stratification of VOCs within the screened
interval. Errors associated with sampler intake placement have
not been quantified to data but are likely strongly controlled by
conditions at each well.
The use of samplers that must pass through the zone of stagnant
water that invariably remains near the water level, even in a
properly-purged well, may also introduce error. For example,
grab samplers, which often require repeated entry and retrieval
from the well during sampling, may be contaminated by this
zone of stagnant water or may mix stagnant water into the water
column. Ukewise, if the purging device is not used for sampling,
removal of the purging device and installation of the sampling
device may have a similar effect. The use of a dedicated device
for both purging and sampling would significantly reduce this
source of error but may introduce others.
SAMPLE FILTRATION
Ground-water samples collected for analysis of certain constitu-
ents are often filtered in the field prior to transfer to the appropri-
ate container. Reasons for filtration include prevention of
geochemical reactions that might occur with particulates during
sample shipment and storage, removal of suspended sedi-
ments so as to analyze only dissolved constituents, and removal
of fine-grained sediments which might interfere with laboratory
analyses. Because filtration may contribute to sample error by
the method employed or by the choice to filter, it is of the utmost
importance to confirm the objectives of the sampling program
and the implications of filtering when choosing whether to filter
and, if so, the filtration technique.
Puis and Barcelona (1989) point out that if.mabile trace metal
species are of interest to the investigation filtration may remove
metals adsorbed onto some colloidal particles, leading to under-
estimates of dissolved metals concentrations and, therefore,
concentrations of mobile species. Conversely, if the objective of
metals analysis is to quantify total dissolved metals concentra-
tions, colloids with aorbed metals that pass through the filter
material may result in overestimates of dissolved metals con-
centrations (Puis and Barcelona, 1989). These workers indicate
that filtration should not be used as a means of removing from
the sample particulates that result from poor well construction,
purging, or sampling procedures because the misapplication of
filtration may introduce substantial bias to trace metal determi-
nations. If filtration is deemed necessary, it should be conducted
soon after sample collection as temperature changes, CO,
15
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invasion, or the presence of particulates may have adverse
affects on traca metal concentrations or dissolved solids content
(Unwin, 1982). Factors important to proper field filtration include
filter pore size, material, and method, and holding time prior to
filtration.
Filter pore size has very important implications for determina-
tions of metal species and major ions in ground-water samples
as a result of the inclusion of undissolved material. Constituents
showing the greatest sensitivity to filter pore size include iron
and zinc (Gibbet al., 1981), iron and aluminum (Wagemann and
Brunskill, 1975), and iron, aluminum, manganese, and titanium
(Kennedy et al., 1974). In all cases, larger filter pore sizes
produced higher concentrations of these constituents because
the larger pore-size filters allowed more particulates to pass. In
fact, Kennedy et al. (1974) found that concentrations of some
metal species in samples filtered through 0.45 urn filters were up
to five times higher than in samples filtered through 0.10 jim
filters. These results suggest that if field-filtering is deemed
necessary, smaller pore size filters may reduce sample error.
Sorptive losses of trace metals during filtration can also intro-
duce error into metals determinations. Truitt and Weber (1979)
found that both cellulose acetate and polycarbonate 0.4 )im filter
membranes sorted copper and lead from solution. For ex-
ample, losses of copper averaged 8.6% with cellulose acetate
membranes and 1.1% with polycarbonate membranes.
Gardner and Hunt (1981) found that sorption of lead onto
cellulose acetate membranes resulted in losses of 20 to 44%
from a synthetic solution. These losses were reduced to 5 to
24% by pre-rinsing the filter apparatus with the test solution
(Gardner and Hunt, 1981). Studies by Jay (1985) found that
virtually ail filters require pre-rinsing to avoid sample contamina-
tion by leaching of anions from the filter material
Although filter material and pore size have been the subject of
considerable research, less effort has been directed toward
understanding the effects of filtration method on dissolved
constituents. Of the few studies available, Stolzenburg and
Nichois (1985) investigated the effects of sampling and filtration
method on concentrations of iron and arsenic. Their laboratory
study showed that samples that were vacuum-filtered after a 10-
minute holding time delay experienced lion losses of 20% to
90% and arsenic losses of 46% to 100% compared to in-line
filtered samples. The rangesof percentages wereduetothe use
of several types of sampling devices. Later experiments by
Stolzenburg and Nichols (1986) added immediate vacuum
filtering of samples. Both immediate and delayed vacuum-
filtration produced similar iron concentrations but these concen-
trations were 17% to 67% lower than concentrations produced
by in-line filtration. In both the 1985 and 1986 reports, in-line
filtering produced concentrations that were comparable to the
source concentrations of approximately 8 mg/L iron and 0.06
mgfl. arsenic suggesting that in-line filtration methods were the
most effective of those tested. These experiments also sug-
gested that filtration method may cause greater losses of oertain
constituents than the type of aampHng device used. Unfortu-
nately, commonly-used pressure filtration methods were not
compared to in-line and vacuum filtration methods in these
experiments.
Clearly, sample filtration can lead to substantial error in trace
metal determinations even if procedures are carefully followed.
Because of this great potential for error, filtration should not be
used to correct for sedimentation problems that result from
poorly designed or constructed wells or incomplete develoD
ment. If filtration is deemed necessary, pre-deaning the filters
can reduce error. In addition, the limited research into filtration
methods in ground-water investigations suggests that in-|jno
methods may result in the least sample error. However, even
under ideal conditions, sample filtration may lead to significant
error in determinations of metals concentrations, suggestina
that analysis of both filtered and non-filtered samples should b«
considered.
EQUIPMENT DECONTAMINATION
Contaminants on equipment that contacts ground water and
samples, including drilling equipment, well materials, sampling
devices, and sample bottles may be another source of lamnu
error. Error may be introduced by the addition of contaminant*
to ground water or samples (contamination) or by the convey-
ance of ground water and/or contaminants from one sampling
installation or zone to another (croes-contamination). Croaa
contamination is most often a problem when equipment, particu-
larly sampling devices, is used portably but not properly cleaned
between installations. The process of cleaning equipment
before installation or after sampling is generally referred to aa
decontamination.
Drilling equipment can be a source of gasoline, diesel fuel
hydraulic fluid, lubricating oils and greases, and paint, ad of
which can be introduced into the subsurface during drilUna
operations. In addition, contaminated soil, scale, or water from
the site may enter the borehole directly or by adhering to drilUna
pipe or other down-hole equipment. If these contaminante
originate from other sites or boreholes, cross-contamination
may result (Fetter, 1983). Steam cleaning is often recom-
mended as a method of decontaminating the drilling rig ma
equipment before use and between boreholes. In addition
placing down-hole drilling equipment on plastic sheeting or
other appropriate material while not in use may reduce rnrnaini,
nation from soils or other sources of contaminants at ground
surface.
Well casing and screen materials may oontain residues of th*
manufacturing process including cutting oils, cleaning solvents,
lubricants, and waxes (Aller et al., 1989). These residues muat
be removed prior to well installation to prevent contamination or
other chemical impacts on samples. A procedure generally
recommended is to wash the casing in a strong detergent
solution followed by a tap water rinse (Barcelona et al., 1983-
Curran and Tomson, 1963) although steam cleaning or a high-
pressure hot water wash may be required for removal of soma
oils, lubricants, and solvents (Aller et al., 1989).
Equipment used portably can lead to cross-contamination by
transferring water and contaminants from one installation to
another, in a survey of state and federal environmental regula-
tory agencies, Mickham et al. (1989) found that procedures lor
decontamination of sampling equipment generally include a to
water rinse, add or solvent rinse (depending on type of contami-
nation), organic-free water rinse, and air drying. The survey also
showed that shipment that does not directly contact sampla*
is generaty cleaned by detergent washes and steam cleaning.
These workers found little research into the effectivenees of
decontamination procedures.
16
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Korte and Kearl (1985) suggest that high-volume pumping may
sufficiently clean sampling pumps. In contrast, field experi-
ments oonductad by Matteoli and Noonan (1987) determined
that 90 minutes of pumping clean water through 200 feet of
PTFE tubing was required to reduce the concentrations of
several organic and inorganic constituents to below detection
levels. These workers found that the time required for effective
decontamination was generally related to the type of constitu-
ent. Freon was still detectable after 120 minutes of pumping.
The effects of cross-contamination can be reduced or elimi-
nated by utilizing equipment dedicated to individual monitoring
wells. As discussed previously, a potential disadvantage of this
approach may be interactions between the device and ground
water in the well between sampling events.
The use of plastic sample bottles may be another potential
source of contamination through leaching of organic and inor-
ganic conatituenta from the bottle materials (Gillham at al.,
1983). An experiment comparing acid-washed and water-
washed plastic sample containers determined that the risk of
contamination from trace elements in the bottles was greatest
for cadmium, copper, and zinc (Ross, 1986). In some cases
copper concentrations were 50 times higher in samples col-
lected in bottles that were not acid-washed. Moody and
Undstrom (1977) suggested that plastic sample containers are
most effectively cleaned with rinaes in both hydrochloric acid
and nitric acid to leach impurities from the plastics. Their study
further determined that, after acid-washing, PTFE and PE
containers were the least contaminating plastic or polymeric
materials.
Interference of ground-water sample chemistry may result from
direct introduction of foreign materials to ground water and
samples or from crosscontamination. Although it appears that
currently uaed decontamination procedures are adequate in a
general way, little research has been conducted to determine
the effectiveness of specific procedures for individual contami-
nants. Because they are not standardized, the contribution to
sample error of a particular procedure must be evaluated,
perhaps on a case-by-case basis.
To prevent crosscontamination when using sampling devices
portably. rinsate blanks (also referred to as equipment blanks)
should be collected to ensure the effectiveness of decontamina-
tion procedures. This may be accomplished by flushing or filling
the device with Type II reagentgrade water and collecting a
sample of the rinsate water. Analysis of rinsate blanks for the
contaminants being sampled will provide an indication of the
effectiveness of the cleaning method (U.S. EPA, 1986) and
indicate if modifications of the procedures are required.
SAMPLE TRANSPORT AND STORAGE
Ground-water samplea require proper containers, treatment,
transport, and storage to ensure the chemical and physical state
of the sample is preserved until analysis. Factors that could
potentially lead to error include volatilization, adaorption, diffu-
sion, precipitation, photodegradation, biodegradation, and
croaa-oontamination (Parr at al., 1988). Methods developed,
and widely accepted, to minimize these effects are summarized
in U.S. EPA (1986) and Herzog et al. (1991).
To reduce the potential for bias during sample handling, appro-
priate chemical preservation of samples should take place
immediately upon collection. Increases in pH of 0.3 to 0.4 units
and declines in iron and zinc concentrations of several orders of
magnitude have been observed within seven hours of sample
collection (Schuller et al., 1981). These investigators also noted
slight declines in the concentrations of calcium, potassium,
magnesium, manganese, and sodium in unpreserved samples
within 48 hours of collection. To ensure immediate preservation,
it may be advisable in some cases to add chemical preserva-
tives to bottles immediately before sample collection. If this
method is utilized it is important to prevent the bottle from
overflowing which might cause the loss.of some of the preser-
vative.
Plastic bottles are usually used for metals and major ions
samples to avoid the sorption effects that may occur with glass.
Most types of plastic bottles can be cleaned with hydrochloric
acid and nitric acid rinses which effectively leach impurities from
the material. PTFE and PE bottles tend to not leach impurities
to samples (Moody and Lindstrom, 1977) and therefore are the
easiest to clean and have the lowest potential to contaminate
samples. The quantities of impurities leached in these studies
are in the very low ng/cm* range, generally below the levels in
most site investigations. Sorption of metals onto plastic bottles,
although normally not a problem, is reduced by acidifying the
sample and thereby keeping the metals ions in solution (Parr et
al., 1988). Clearly, if adequate cleaning is carried out and pre-
analysis holding times are not exceeded, contamination of
major ion and trace metal samples by sample bottles is unlikely.
Organic samples are usually placed in glass containers to avoid
the chemical interferences that may occur with plastic bottles.
The borosilicate glaas used in bottles for water samples for
organic analyses is easily cleaned and has very little potential for
contamination of samples or sorption from samples.
Cross-contamination of VOC samples during transport and
storage can be minimized if accepted procedures are carefully
followed. The evidence presently available indicates that cross-
contamination of VOC samples at concentrations typical of
hazardous waste sites is negligble under conditions normally
present during sample storage (Levine et al., 1983; Maskarinec
and Moody, 1988). Levine et al. (1983) did note, however, the
thickness of the PTFE lining under the VOC vial septum was
critical to the prevention of cross-contamination and that con-
tamination was evident when samples were stored near vials
containing saturated aqueous solutions of VOCs. Trip blanks
can be utilized to evaluate the potential for contamination of
samples during shipment to the laboratory. These blanks, which
consist of reagent-grade water in bottles of the same type used
for sampling, can be shipped to the site and laboratory in the
same shipping containers used for samples.
The length of time that a sample can be stored without degrada-
tion is related to the potential sources of error covered here. If
adequate measures are taken to reduce these errors, chemical
alteration of the sample during storage can be minimized. Using
commonly-accepted storage methods, concentrations of VOCs
have been shown to be stable after 34 days (Friedman et al.,
1986) and 56 days (Maskarinec and Moody, 1988).
17
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ANALYTICAL TECHNIQUES
To gain perspective into the relative magnitude and importance
of arrors introduced during ground-water sampling, it is useful to
quantify the errors involved in laboratory analysis. Potential
sources of error in the laboratory include glassware, reagents,
laboratory preparation techniques, and analytical equipment
and apparatus (Lewis, 1988). It is beyond the scope of this
document to discuss how each of these aspects of laboratory
operation can impact sample quality except to say that errors
can be detected and controlled by the use of various quality-
control checks. Vitale et al„ (1991) describe the blanks, dupli-
cate samples, and spikes that ensure the identification of
laboratory error. Through the use of these checks, analytical
errors often can be quantified, unlike many aspects of sampling
protocol where comparison to true' concentrations is usually
impossMe.
In a review of the EPA Contract Laboratory Program (CLP)
database for gas chromatograph/mass spectrometer (GC/MS)
analysis of VOCs, Flotard et al. (1986) analyzed the deviations
in reported concentrations from actual concentrations in blind
performance evaluation samples. These deviations can be
considered measures of analytical errors, with underreported
concentrations considered negative error and overreported
concentrations considered positive error. The Flotard et al.
(1986) study found errors in reported concentrations of 22 VOCs
from -46.4% for 1,1-dichloroethane to 4-6.5% for bromoform.
The results for methylene chloride exhibited an apparent error
of +36.6% but this value was attributed to laboratory contamina-
tion of samples and not analysis error. Their review indicated
that 55% of the 22 evaluated VOCs resulted in reported concen-
trations that were more than 20% lower than actual concentra-
tions. Interlaboratory errors from 35 laboratories were found to
be from -3.9% to zero, although datafrom only three compounds
were analyzed.
A similar review of the CLP database for semi-volatile analyses
conducted by Wolff et ai. (1986) concluded that the greatest
analytical errors were associated with phenolic compounds,
whose concentrations were consistently underreported. Other
classes of semi-volatiles showed no general trends. In that
study, analytical errors ranged from -48% for 1,3-dichloroben-
zene and 2,6-dinitrotoluene to +12% for 4-chlorophenyl-
phenylether. The review indicated thai 60% of the 33 com-
pounds evaluated showed analytical errors in excess of -20%,
slightly more than for VOC analyses. Interlaboratory errors for
six compounds ranged from -51% for phenoi-d, to -16% for p-
terphenyl, considerably greater than for the volatile analyses.
The CLP database has also been evaluated for errors intro-
duced by inorganic analytical methods (Aleckson et al., 1986).
These workers found that analytical errors ranged from -26.5%
to +10.0%, with most errors falling in the range -10.0% to zero.
The greatest negative errors were found for selenium, silver,
and ftaWum.
Barcelona et al. (1989) tabulated laboratory errors for inorganic
constituents during an intensive time-series investigation of
ground-water chemistry variation. They found that errors in
determinations of major ions in external performance samples
ranged from -8.1% (potassium) to +12.1% (total iron). An
evaluation of eight analytical laboratories was conducted by
Rice et al. (1988) as part of a uranium mill tailings ground-water
quality investigation. Constituents of interest included total
dissolved solids, major ions, trace metals, and radionuclides.
Analysis of external performance samples during the study
showed that 67% of all analyses were within the acceptable
range but that 60% of the reported values were higher than the
known concentrations. Iron and aluminum were among the
constituents showing the highest analytical errors.
SUMMARY AND CONCLUSIONS
As shown here, many aspects of ground-water investigations
may introduce error into determinations of concentrations of
hydrochemical constituents. The potential errors associated
with many of these aspects are summarized in Table 5.
Errors produced during certain aspects of sampling programs
can be identified, quantified, and controlled through the use of
accepted procedures in conjunction with performance evalua-
tion samples. For example, equipment decontamination and
sample transport and storage have considerable potential for
introducing sample error if not conducted in a careful and
consistent manner. In the case of equipment decontamination,
collection and analysis of rinsate blanks from cleaned equipl
ment can be useful for evaluating the effectiveness of decon-
tamination procedures. Likewise, errors that may occur during
sample transport can be identified by the use of trip blanks that
are transported to the site and laboratory in the same shipping
containers as field samples. An asfMct that may require
particular attention and further research is the effectiveness of
decontamination of flexble tubing used for conveying samples
from the sampler to sample bottle.
The potential errors associated with other aspects of sampling
programs are relatively weH understood and can be minimized
through appropriate choice of equipment and materials. For
instance, advances in sampling device design and construction
have resulted in the development and widespread use of posi-
tive displacement sampling devices whose operation generally
introduces little sample error. For most compounds, including
VOCs, positive displacement devices allow collection of accu-
rate and precise samples, with concentrations of VOCs typically
within 10% of true concentrations. Some grab samplers, par-
ticularly bailers, may also produce representative samples but
their effectiveness is highly dependent on mode of operation
and the constituents of interest. Under unfavorable field condi-
tions or when operated improperly, bailers may produce errors
in VOC concentrations from -10% to -80% or more. Most other
types of samplers produce errors of unpredictable magnitude
but show VOC errors of at least -20% in controlled laboratory
experiments. The unpredictable magnitude of errors associated
with many of these devices also means that they often cannot
provide the precise, or repeatabie, measurements usually asso-
ciated with positive displacement devices. As a result, the use
of positive displacement sampling devices may minimize the
introduction of error into determinations of the concentrations of
sensitive hydrochemical constituents. Use of other types of
devices may introduce error of unpredictable magnitude.
Potential impacts of materials used in weB and sampler con*
struction have been demonstrated, but the implications of these
effects in a field setting remain unclear. Laboratory comparison
studies conducted under static conditions have demonstrated
18
-------
the potential for rigid PTFE, PVC, and metallic materials to
introduce error into concentration* of some trace metals and
hydrocarbon compounds. However, little work has been con-
ducted under conditions simulating dynamic ground- or sample-
water flow or, more importantly, well-purging effects. Despite
these unresolved issues, materials' impacts can be minimized
by choosing well materials compatible with the objectives of the
sampling program and the hydrogeologic and hydrochemical
conditions of the site. The proper choice of materials can reduce
chemical effects on water stored in the well between sampling
events and make removal of stagnant water during well purging
less difficult. When monitoring for low hydrocarbon concentra-
tions in non-corrosive ground water, SS and PVC casing may be
the most appropriate choices. Because PTFE has been shown
to introduce error into hydrocarbon determinations, it may be
most applicable under conditions where SS and PVC are not
considered appropriate. For example, SS would probably not be
considered an appropriate material in corrosive ground water or
where determinations of trace metal concentrations are of
primary concern. Likewise, PVC probably would not be consid-
ered an appropriate material in situations where solvents in
moderate to high concentrations might dissolve the PVC mate-
rial.
Flexible tubing can introduce significant error through sorption
of contaminants onto tubing material, leaching of constituents of
the tubing material into sampled water, and possibly transmis-
sion of organic compounds and gases through tubing wails.
These errors are generally greater than for rigid materials and
may be particularly important during site remediation efforts
when declines in ground-water concentrations may be masked
by desorption of previously sorted compounds. Laboratory
research has demonstrated the potential for errors under static
conditions, but further research is required to understand how
sorption/desorption mechanisms can impact samples during
the dynamic sampling process. These studies suggest, how-
ever, that sample error can be minimized by substituting PTFE
for other types of flexible materials.
Rltratlon of samples for trace metals determinations may intro-
duce sample error either by the equipment and methods utilized
or by the actual decision tof ilter. Due to the presence of colloidal
sized particles in ground water, filtration can have dramatic
impacts on determinations of the concentrations of both mobile
and total dissolved metals. Indiscriminate filtration of metals
samples may lead to gross errors in these concentrations and
result in erroneous conclusions about ground-water transport of
metals. In view of this, the objectives of the sampling program
must be carefully considered before samples are filtered. If it is
decided to filter samples, in-line filtration with pre-deaned, lower
pore-size filters can reduce errors associated with filtration.
In contrast to moat aspect* of the sampling process, errors
introduced during laboratory analysis may be relatively weH
quantified. Analysis of the CLP database has shown errors in
reported concentrations of performance samples of -20% to
-30* for volatile and semivolatile compounds and -10* to zero
for inorganic constituents. Errors in analytical methods, as with
sample transport, sample storage, and equipment decontami-
nation, can be quantified for individual investigations by analyz-
ing standards and blind quality evaluation samples. Although
the magnitude of analytical error may be greater than the error
introduced during some aspects of sample collection, analysis
of quality evaluation samples leads to easier identification and
quantification of analytical error.
Errors associated with other aspects of site investigations,
including well drilling and construction, are more difficult to
identify because true concentrations of hydrochemical constitu-
ents are unknown in field investigations. During the drilling
phase of site investigations, hydrogeologic disturbances can be
minimized by utilizing appropriate drilling methods. Likewise,
drilling-related hydrochemical disturbances can be reduced by
avoiding the use of fluids that might alter ground-water chemis-
try through ion exchange reactions or exposure to organic
polymers. Well construction and development methods appro-
priate to the site hydrogeologic conditions are capable of remov-
ing artifacts from the drilling process and improving the hydraulic
efficiency of the well with minimal impact on subsequent
samples. Proper design, installation, and isolation of cement or
bentonite seals reduces the potential for chemical alterations
from these materials. Any of these aspects of drilling and well
construction can lead to large errors if not carefully controlled,
however, the magnitude of error is directly related to site
conditions and the extent to which methods have been misap-
plied. Careful consideration and application of methods and
materials during well drilling and construction can significantly
reduce sample error.
Well purging method, purging rate, and the volume purged prior
to sample collection all possess great potential for introducing
significant error when sampling for sensitive constituents. For
example, setting the purging device far below the air-water
interface and using a high purge rate may contaminate samples
by allowing stagnant water to mix with sampled water. However,
it is possible to identify these potential sources of error and
modify purging procedures to minimize the errors. Conducting
a preliminary purge test may aid in identification of the depth and
rate that results in the most representative samples, however,
determination of when purging is complete (purge volume) may
be more difficult Although purge volume can be calculated by
several indirect methods, this volume may not directly correlate
with the volume of water required to provide representative
samples. In particular, stabilization of the values of field chemi-
cal indicator parameters such as temperature, pH, and EC may
not coincide with stabilization of other hydrochemicai param-
eters and constituents. Due to the often complex three-dimen-
sional distribution of many contaminants, concentrations of
individual constituents may not stabilize at the same time, or
may never stabilize. Despite these possibilities, the potential for
sample error can be reduced by choosing indicator parameters
that are sensitive to the purging process and relate to the
constituents of interest.
To reduce error when sampling for constituents that may be
associated with colloids, or other very sensitive constituents, it
is particularly important to minimize disturbance of the samples
and the sampling environment during the purging and sampling
process. To this end, reducing or eliminating purging, minimiz-
ing purging and sampling flow rates, and using dedicated
sampling devices plaoed within the weO intake interval should all
be considered. Because this issue remains unresolved, general
recommendations are not possible and it may be necessary to
conduct preliminary purge tests to determine how indicator
19
-------
parameters and concentrations of important constituents vary
with purging rate, volume, method, and distribution of contami-
nants around the well. Inadequate determination of these
factors may lead to order-of-magnitude, or more, errors in
concentration determinations, especially in low-yield wells.
The errors most critical to sampling programs are those that are
difficult or impossible to identify because important conclusions
may be unknowingly based on erroneous or inadequate data.
Well location and design are aspects of sampling that are very
likely to produce undetected errors. Errors produced by well
location are virtually impossible to identify because their magni-
tude is entirely specific to that particular location. The appropri-
ate placement of a well can mean the difference between
detection of a contaminant plume or missing it entirely, so the
potential for error is virtually infinite. Even if a well is located in
the targeted zone of contamination or plume, little can be
deduced about small-scale hydrogeologic properties or con-
taminant distribution without a well-designed monitoring net-
work that accounts tor individual site characteristics and pro-
gram objectives.
Well design, particularly the depth and interval of the well intake,
can also be a large potential source of undetectable errors. To
delineate the vertical distribution of contaminants at a single
location, samples must be collected at specific depths, hence,
wells must be screened over short intervals and adequately
sealed between sampling zones. Dilution and cross-contam ina-
tion resulting from long-screened wells or poor well seals may
produce order-of-magnitude errors in concentrations that far
outweigh errors produced in all other aspects of the sampling
process. For example, dilution of samples collected from long-
screened remediation wells may mask true contaminant con-
centrations, leading to erroneous conclusions about the effec-
tiveness of remedial efforts.
In conclusion, it can be stated that virtually all aspects of ground-
water investigations, from well location to laboratory analysis
have the potential to introduce error into the determinations of
concentrations of hydrochemical constituents. General defini-
tion of the magnitude of potential errors is difficult becaus*
errors will be influenced by the complex interaction of geologic
hydraulic, and hydrochemicat conditions unique to each site, as
well as the design and performance of the sampling program
Potential sources of error related to site conditions must be
identified during early phases of the remedial investigation (Rh
and then minimized by careful design of the sampling program
Modifications to the program design may then be necessary to
address issues that might arise as the Rl proceeds. Methods of
detecting errors that may be introduoed during the performance
of the sampling program must be utilized so that these errors can
be identified and minimized. However, errors that are difficult or
impossfcie to detect may provide the greatest obstacles to the
collection of representative data.
TABLE 1 POTENTIAL SOURCES OF ERROR ASSOCIATED WTTH ELEMENTS OP GROUND-WATER SAMPLING PROGRAMS
AT HAZARDOUS WASTE SITES.
Program Element Type of Error
Afaiity
to Avoid
Error Mtfhods for Error Avoidance
Abilty
to Detect
Error Methods for Error Detection
Wsl Intake Length Long-screened and mufti- Easy to
scmntd wall miy toad to Modarala
crateofltamMion of
coranwMon anaon.
Wsl Intake Daplh Wei Make may miss zone Easy to
n niim
Wsl Intake Design Presence of particulates
in sample.
FtterPack Presence of psrticulatoi in Easy to
samples. Reaction with lltof Modnie
pack iMteriais or introduced
Easy to
L J L -
rrywuunwwpy. viki
connection oinaturaly
isolated anee if fter pack
too lorn, bmaakM oi borehole
smI fiMlnWi If ttaf pack
too short.
identify apecMc zones of interest
Use Make langMi appropriate to
program objectives and hydrogeologic
— — -J
in nymuuwmcB oonouvR*
wnwy yum am w iiiim
Use intake lengti appropriate to
program objectives and hydrogso-
»— -i »- «- —«- -* «*»« . -
lope ino iiywuuiaiMcai ooranrv.
Design in conjunction wMi Mar
pack lor hydrogeologic condWone.
Design in conjunction wthwel
intake far hydrogeologic conditions.
Use dsan, norweadlve materials.
Inetal with tiemie pipe and measure
depths and volumes during MaMion
to ensure ooirecl placement.
Compere with data tan short-
scrwnwelsorlsld-scrooning
DMa*
OMcuk Compare with data tan other
wobortokt-scrooning
Easy to Turt)id samples.
Moderate
Eaayto Turbid samples.
Moderate SoiptionAeachingstudfceof
materials before instaiation.
(Continued)
20
-------
Program Element Type of Error
TABLE 1 CONTINUED.
Ability
to Avoid
Error Methods for Error Avoidance
Ability
to Detect
Error Methods for Error Detection
Borehole Soals
Wei Location
Drilling
WM Development
Material*
If improperly placed, Moderate
-bertonito materials may altar
hydrochamiatry through ion
axchango. N improperly
piaoed, cement may elevate
valuaa of ground-water pH,
KftMratfiillw minium
*wfMmmj, CMCMTi
concentration.
Inadaquaia coverage of
area of investigation.
Depends on mathod.
Contamination by drffng or
othar luids may alar
hydrochamiatry. Smaaring
and mixing of fluids and
sediments at borehole
wal. Craaa-oontamination
within borahoia.
Dapands on mathod. Easy to
Incomplete development may Moderate
laad to turbid samples or poor
hydraulic efficiency. Alteration
of hydrochamistry by develop-
mart action. Introduction of
contaminanls (including air
and water).
Dapands on material, Easy to
contaminants, hydrochemical Modarata
condMona. and time of contact.
SorpfonAJaaorptionof
awmcm oonsmusw.
teaching of constituents from
materials'matrfe. Biologic
activity. Poasfcia transmission
through laxHa materia*.
Dasign for hydrogaologic conditions.
Isoiala aaals from samping zona.
Instal with tramia pipa and maasura
dapths and volumes during instalation
to ensure corract placamant.
Modarata CaraM dasign of monitoring waN
Modarata
CaraM considaralion and application
of mathods that ara appropriate for
program objactivas and hydrogaologic
and hydrochamical conditions.
Minimizo use of water-based driSng
fluids and additives. If constituents
sensitive to atmospheric exposure wl
be sampled, minimize uaa of air-based
drilling fluids. Determine the chemical
quality of drWng fluids used. Use
appropriate development methods to
minimize impacts of drflfng.
Careful consideration and application
of methods that are appropriate for
program objectives and hydrogaologic
and hydrochamical conditions. Avoid
addbig luids to wal. If adding fluids is
necessary, determine the chemical
quality of the luids used.
Select materials that are appropriate
lor program objectives and hydro-
geologic and hydrochemical conditions.
Use appropriate wal purging techniques.
Moderate Bentonite: High sodium con-
to Difficult centrations if sodium bentonite
used and samples are highly
contaminated. Cement:
SarViple pH over 10, and high
EC, alkalinity, and calcium
concentrations.
Difficult Compare with data from
nearby wells or field-
screening methods.
Moderate Drilling fluid contamination:
to Difficult Depends on composition of
fluid. Compare with data Irom
nearby wells and field-
screening methods. Evaluate
chemical quality of fluids used.
Moderate Turbid samples and production
of sedments during pumping
may indicate incomplete
development or inadequate
design of filter pack and wel
intake. If fluids were added,
evaluate chemical quality of
fluids used.
Difficult Sorptkxvleaching studies of
materials before installation.
Detection after installation
depends on material,
contaminants, hydrochemical
conditions, and time of contact.
(Continued)
21
-------
TABLES. CONTMUED.
Program Element Type of Error
Ability
to Avoid
Error Methode for Error Avoidance
AWNty
to Detect
Error Methods for Error Detection
Wel Purging
Sampling Device
Incomplete removal ol
stagnant water (walar
affected by contact with
atmoaphara and we* and
sampling davica malariats).
Disturbance ol ambient
hydrochemical conditions.
Conduct purge-volume test w
datermine when parameter _
constituents of interest
stable values
Depends on operating
princtye of sampling device.
Sorption, desorption, and
leaching tram material.
Degassing or voiatMzation
hom sample. Atmoapheric
Easy to Chooee indicator parameters that are Easy to
Moderate sensitive to purging process and retoe Moderate
(Moderate to the chemical constituents ol interest. (Moderate
to Difficult Conduct purge-volume test to determine to Difficult
under *rtien parameters or constituents ol under
low-yield interest reach stable values. Determine low-yield
conditions) if low low-rale and/or low volume conditions)
purging is appropriate. II not, minimize
volume of stagnant water above device
intake by purging near water surtaoe or
lower dwice during purging or before
sampling. Avoid drawing water level
below top of wel intake.
Easy Select device that ia appropriate for Moderate Depends on sampler typ*
sample type, hydrochemical conditions, to Difficult Compare with data collactM
and program objectives. with other devicee.
Sample CoNection
Time and Depth
Sample RUration
Mbcing wth stagnant walar
inwell. As time after purging
increase, water in wel
becomes mora stagnant.
Type ol flier system used
and length of pre-litmion
halting lime determines
extent of temperature
changes, tfmoapheric
contamination, degassing,
and smptkni onto particulslea.
Fier pore size may afleet
passage of csrtain constituents
and suspended malarial.
Flar malarial and Nor pre-
cleaning may affect reeufts.
Erroneous conclusions about
metals concentrations may
reeull from asaociation of
metals with coloids.
Easy Colect samples from within or im-
mediately ibove wel intake. Use
appropriate sampling nla. Avoid
moving sampler within water column
(wnng sampling. rugn-yMQ wms.
Sample immadialely alter purging.
Low-yield well: Determine
appropriate lime based on responae
of wel and purge-volume teat.
Easy to Determine of Rralion is necessary
Moderate for the objectives of the program.
Minimize pre-Mration holdfog time.
Use pre daaned Inline filters. Some
situations may warrant use of pore
sizee after than 0.45pm.
Moderate Test different scenarios ajyj
to Difficult compare results, although
be very difficult to determin®^
which results are the most
representative.
Moderate Compare analytical result*
fltered and unilterad svnpi^
Compare analytical reauteof
dMerent filtration methods.
(Continual)
22
-------
TABLES. CONTINUED.
Program Element Type of Error
Ability
to Avoid
Error Methods for Error Avoidance
Ability
to Detect
Error Methods for Error Detection
Equipment Croat-contamination Easy
Decontamination between we*s H sampling
aquipmant is uaad port ably.
IncompMe removal ol
residues from manufacture
or contaminants from
storage, transport, or use.
Sample Preservation Changee in hydrochemistry
during sample shipment
and storage.
Sample Transport
and Storage
Croafrcontamination
btfwMn tmptobollliCi
Materials' effects from
sample botUaa. Loeeot
volsileconstkuents.
Easy
Eaay
Use appropriate cleaning and
decontamination prooadurea.
Use appropriate physical and
chemical preeervation procedures.
Use appropriate sample bottle type
and dewing procedure.
Do not exceed sample holding timee.
Easy Coded rinsate blanks alter
deaning.
Moderate Indirectly identified by
to difficult, evaluating how wall
procedures are being
Mowed.
Easy Transport trip blanks with
Laboratory AraJysis Deviation from due Moderate
concantratione.
Use appropriate analytical methods
and laboratory procedures.
Easy to Analyze blind performance
Moderate evaluation samples, blanks,
and standards.
23
-------
REFERENCES
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analytical methods performance and quality control consider-
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Hazardous and Industrial Solid Waste Testing, Fifth Volume,
ASTM STP 925, C. L Perket, ed. American Society for Testing
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Aller, L.. T. W. Bennett, G. Hackett, R. J. Petty. J. H. Lehr, H.
Sedoris, 0. M. Nielsen, and J. E. Denne, 1989. Handbook of
Suggested Practices for the Design and Installation of Ground-
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Andricevic, R. and E. Foufoula-Georgiou, 1991. A transfer
function approach to sampling network design for groundwater
contamination. Water Resources Research. Vol. 27, No. 10.
pp. 2759-2769.
Barcelona, M. J., J. P. Gibb, and R. A. Miller, 1983. A Guide to
the Selection of Materials for Monitoring Well Construction and
Ground-Water Sampling. Illinois State Water Survey Contract
Report No. 327. U.S. Environmental Protection Agency. EPA/
600/52-84/024. 78 p.
Barcelona, M. J., 1984. TOC determinations in ground water.
Ground Water. Vol. 22, No. 1. pp. 18-24.
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February 1991
&EPA Ground-Water Issue
SOIL SAMPLING AND ANALYSIS FOR
VOLATILE ORGANIC COMPOUNDS
T. E. Lewis, A. B. Crockett, R. L. Siegrist, and K. Zarrabi
The Regional Superfund Ground Water Fo-
rum is a group of ground-water scientists that
represents EPA's Regional Superfund Of-
fices. The forum was organized to exchange
up-to-date information related to ground-
water remediation at Superfund sites. Sam-
pling of soils for volatile organic compounds
(VOCs) is an issue identified by the Ground
Water Forum as a concern of Superfund de-
cision makers.
A group of scientists actively engaged in
method development research on soil sam-
pling and analysis for VOCs gathered at the
Environmental Monitoring Systems Labora-
tory in Las Vegas to examine this issue.
Members of the committee were
R. E. Cameron (LESC), A. B. Crockett
(EG&G), C. L. Gerlach (LESC), T. E. Lewis
(LESC), M. P. Maskarinec (ORNL),
B. J. Mason (ERC), C. L. Mayer (LESC),
C. Ramsey (NEIC), S. R. Schroedl (LESC),
R. L. Siegrist (ORNL), C. G. Urchin (Rutgers
University), L. G. Wilson (University of
Arizona), and K. Zarrabi (ERC). This paper
was prepared by The Committee for EMSL-
LV's Monitoring and Site Characterization
Technical Support Center, under the direction
of T. E. Lewis, with the support of the
Superfund Technical Support Project. For
further information contact Ken Brown, Center
Director at EMSL-LV, FTS 545-2270, or T. E.
Lewis at (702) 734-3400.
PURPOSE AND SCOPE
Concerns over data quality have raised many
questions related to sampling soils for VOCs.
This paper was prepared in response to some
of these questions and concerns expressed
by Remedial Project Managers (RPMs) and
On-Scene Coordinators (OSCs). The follow-
ing questions are frequently asked:
1 ¦ Is there a specific device suggested for
sampling soils for VOCs?
2. Are there significant losses of VOCs when
transferring a soil sample from a sampling
device (e.g., split spoon) into the sample
container?
3. What is the best method for getting the
sample from the split spoon (or other
device) into the sample container?
4. Are there smaller devices such as
subcore samplers available for collecting
aliquots from the larger core and effi-
ciently transferring the sample into the
sample container?
5. Are certain containers better than others
for shipping and storing soil samples for
VOC analysis?
6. Are there any reliable preservation proce
dures for reducing VOC losses from soil
samples and for extending holding times?
This paper is intended to familiarize RPMs,
OSCs, and field personnel with the current
state of the science and the current thinking
concerning sampling soils for VOC analysis.
Guidance is provided for selecting the most
effective sampling device for collecting
^ T \
J I ac/irology t-
O <*> z
o O
\f*~ J
Superfund Technology Support Center
for Monitoring and Site Characterization
Environmental Monitoring Systems
Laboratory Las Vegas, NV
Technology Innovation Office
Office of Solid Waste aid Emergency Response,
U.S. EPA, Washington, D.C.
Water W. Kovalick, Jr., Ph.D., Director
Printed on Recycled Paper \
-------
samples from soil matrices. The techniques for sample collec-
tion, sample handling, containerizing, shipment, and storage
described in this paper reduce VOC losses and generally
provide more representative samples for volatile organic analy-
ses (VOA) than techniques in current use. For a discussion on
the proper use of sampling equipment the reader should refer
to other sources (Acker, 1974; U.S. EPA, 1983; U.S. EPA,
1986a).
Soil, as referred to in this report, encompasses the mass
(surface and subsurface) of unconsolidated mantle of weath-
ered rock and loose material lying above solid rock. Further, a
distinction must be made as to what fraction of the unconsoli-
dated material is soil and what fraction is not. The soil compo-
nent here is defined as all mineral and naturally occurring
organic material that is 2 mm or less in size. This is the size
normally used to differentiate between soils (consisting of
sands, silts, and clays) and gravels.
Although numerous sampling situations may be encountered,
this paper focuses on three broad categories of sites that might
be sampled for VOCs:
1. Open test pit or trench
2. Surface soils (< 5 ft in depth)
3. Subsurface soils (> 5 ft in depth)
INTRODUCTION
VOCs are the class of compounds most commonly encoun-
tered at Superfund and other hazardous waste sites (McCoy,
1985; Plumb and Pitchford, 1985; Plumb, 1987; Ameth et al.,
1988). Table 1 ranks the compounds most commonly encoun-
tered at Superfund sites. Many VOCs are considered hazard-
ous because they are mutagenic, carcinogenic, or teratogenic,
and they are commonly the controlling contaminants in site
restoration projects. Decisions regarding the extent of contami-
nation and the degree of cleanup have far-reaching effects;
therefore, it is essential that they be based on accurate mea-
surements of the VOC concentrations present. VOCs, how-
ever, present sampling, sample handling, and analytical diffi-
culties, especially when encountered in soils and other solid
matrices.
Methods used for sampling soils for volatile organic analysis
(VOA) vary widely within and between EPA Regions, and the
recovery of VOCs from soils has been highly variable. The
source of variation in analyte recovery may be associated with
any single step in the process or all steps, including sample
collection, transfer from the sampling device to the sample
container, sample shipment, sample preparation for analysis,
and sample analysis. The strength of the sampling chain is only
as strong as its weakest link; soil sampling and transfer to the
container are often the weakest links.
Sample collection and handling activities have large sources of
random and systematic errors compared to the analysis itself
(Barcelona, 1989). Negative bias (i.e., measured value less
than true value) is perhaps the most significant and most
difficult to delineate and control. This error is caused primarily
by loss through volatilization during soil sample collection,
storage, and handling.
TABLE 1. RANKING OF GROUND WATER CONTAMINANTS BASUix
ON FREQUENCY OF DETECTION AT 358 HAZARDOUS WASTE
DISPOSAL SITES
Contaminant
Detection Frequency
Trichloroetheno (V)
51.3
Tetrachloroethene (V)
36.0
1,2-trans Dichioroethene (V)
29.1
Chloroform (V)
28.4
1.1-Dichloroethene(V)
25.2
Methylene chloride (V)
192
1.1,1 -Trichtoroethane (V)
18.9
U-Dichlofoethane (V)
17.9
1.2-Dichloroethane(V)
14.2
Phenol (A)
13.6
Acetone (V)
12.4
Toluene (V)
11.6
bis-(2-Ethylhexyl) phthalate (B)
11.5
Benzene (V)
11.2
Vinyl chloride
8.7
V'WtaM.A-acttMractabto, B-batrtwutial
Source: Plumb and Pitchford (1985).
There are currently no standard procedures for sampling son*
for VOC analyses. Several types of samplers are available fJl
collecting intact (undisturbed) samples and bulk (disturb*^
samples. The selection of a particular device is site-specific
Samples are usually removed from the sampler and are placM
in glass jars or vials that are then sealed with Teflon-lined capjr
Practical experience and recent field and laboratory research
however, suggest that procedures such as these may lead tr»
significant VOC losses (losses that would affect the utility of th»
data). Hanisch and McDevitt (1984) reported that anv
headspace present in the sample container will lead to desorty.
tion of VOCs from the soil particles into the headspace and vjm
cause loss of VOCs upon opening of the container. Siegrist and
Jennsen (1990) found that 81% of the VOCs were lost from
samples containerized in glass jars sealed with Teflon-iin^n
caps compared to samples immersed in methanol in jars.
FACTORS AFFECTING VOC RETENTION AND
CONCENTRATION IN SOIL SYSTEMS
Volatile organic compounds in soil may coexist in three phas«s-
gaseous, liquid (dissolved), and solid (sorbed). [Note: "Sorbtt^*
is used throughout this paper to encompass physical and
chemical adsorption and phase partitioning.] The sampling
identification, and quantitation of VOCs in soil matrices ar»
complicated because VOC molecules can coexist in the**
2
-------
three phases. The interactions between these phases are
illustrated in Figure 1. The phase distribution is controlled by
VOC physicochemical properties (e.g., solubility, Henry's
constant), soil properties, and environmental variables (e.g.,
soil temperature, water content, organic carbon content).
I VOLATILIZATION
!p,-k„cw
+ (Henry's Law)
Temperature,
wind, humidity,
hydrodynamics,
barometric
pressure,
surface features

EXTERNAL
FACTORS
SORPTION
<1"K,CW
(Linear Isotherm)

Temperature,
hydrodynamics,
surfaoe features
Figure 1. Equilibrium relationships for phase partitioning of
VOCs in soil systems. See Table 2 for definitions
of abbreviations.
The factors that affect the concentration and retention of VOCs
in soils can be divided into five categories: VOC chemical
properties, soil chemical properties, soil physical properties,
environmental factors, and biological factors. A brief summary
ol VOC, soil, and environmental factors is presented in Table 2,
which provides an overview of the factors that interact to control
VOCs in the soil environment at the time a sample is collected.
The cited references provide a more detailed discussion. The
chemical and physical properties of selected VOCs are further
described in Table 3. Note that many of these properties have
been determined in the laboratory under conditions (e.g.,
temperature, pressure) that may differ from those encountered
in the field. Devitt et al. (1987) offers a more exhaustive list.
Many VOCs exhibit extreme mobilities, particularly in the vapor
phase, where their gas diffusion coefficients can be four times
greater than their liquid diffusion coefficients. The vapor phase
migration is influenced by the moisture content of the soil which
alters the air-filled to water-filled pore volume ratio. The reten-
tion of VOCs by soil is largely controlled by reactions with the
solid phase. This retention is especially true for the finer
particles of silts and clays. The fine-grained particles (<2 mm)
have a large surface-to-volume ratio, a large number of reactive
sites, and high sorption capacities (Richardson and Epstein,
1971; Boucher and Lee, 1972; Lotse et al., 1968). Some
investigators attribute the greater sorption of VOCs onto fine-
grained particles to the greater organic carbon content of
smaller particles (Karickhoff et al., 1979).
Soil-moisture content affects the relative contributions of min-
eral and organic soil fractions to the retention of VOCs (Smith
etal., 1990). Mineral clay surfaces largely control sorption when
soil moisture is extremely low (<1%). and organic carbon
(Continued on page 7)
TABLE 2. FACTORS AFFECTING VOC CONCENTRATIONS IN SOILS
Factor
Common
Abbr. Units
Effects on VOC Concentrations In SoH
VOC Chemical Properties
Solubility
Henry's Constant
Vapor pressure
Organic cartxxi part, coeff.
Octanol/water part, coeff.
Boiling point
Soil/water distribution
coefficient
C. mg/L
(atm-ms)/mole
v.p. mm Hg
K, mgVOC/gC
K„ mg VOC/
mgoctanol
b-P-
•C
11]
Affects fate and transport in water, effects
water/air partit., influences organic carbon partit.
Constant of proportionality between the water and gas
phase concentrations; temperature and pressure dependent.
Affects rate of loss from soil.
Adsorption coefficient normalized for sol organic content
EquiKbrium constant for distribution of VOC between water
and an organic (octanol) phase. Gives estimate of VOC
partitioning into organic fraction of sol.
Affects co-evaporation of VOC and water from soil surface.
EquUbrium constant for distribution of contaminant between
solid and liquid phases.
Roy and Griffin (1985)
Shen and SeweH (1982)
Spencer etal. (1988)
Shen and Sewed (1982)
Farmer st al. (1980)
Voice and Weber (1983)
Voice and Weber (1983)
Voice and Weber (1983)
(Continued)
3
-------
TABLE 2. (CONTMUED)
Factor
Common
Abbr.
Unto
Effects on VOCConcentratlona in Sol
Sol ChMRical PraptrtiM
Cation exchange capacity CEC meqflOOg
ion concentration
(activity)
pH -toflCH*)
Total organic carbon content TOC mgC/gsoil
Aa|| RwyiaailM
901 rlljW H^pIW
Parlide size or texture
Specific surface area
Bulk density
Porosity
Percent moisture
mmpommm
Hydraulic conductivity
A %sand,
sit, day
s.a.
P»
n
e
PF
K
mVg
g/cm3
%
%(w/w)
m
rrtd
Estimates the number of negatively chargsd sites on sol
particles where charged VOC may sorb; pH dependent
Influences a number of sol processes that involve
non-neutral organic partitioning; afiects GEC and
solubMty of some VOCs.
An important partitioning medkjm for non-polar, hydrophobic
(high KJ VOCs; sorption ol VOCs in this medwm may be
htyly jrrevsrsMe.
Affects infiltration, penetration, retention, sorption, and
mob#ty of VOCs. Influences hydraulics as wet as surface-
area-to-volume ratio (s.a.<*Kd).
Afiects adsorption of VOCs from vapor phase; affects sol
porosity and other taxtural properties.
Used in estimating mobity and retention of VOCs in sols;
wM influence sol sampling device selection.
Void volume to total volume ratio. Affects volume,
concentration, retention, and migration of VOCe in sol voids.
Afiects hydrauNc conductivity of soil and sorption of VOCs.
Determines the dtesokition and mobity of VOCs in sol.
Relates to the rate, mobity, and concentration of VOCs
in watsr or Kquid chemicals.
Chiouetal. (1988)
Farmer etal. (1980)
Richardson and
Epstein (1971)
Karickhoffetal. (1979)
Spencer etal. (1988)
Farmer etal. (1980)
Shen and Sewell (1982)
Fanner etal. (1980)
Chiou and Shoup (1965)
Affects viecous flow of VOCs in sol water dspendng on
degree of saturation, gradants, and other physical factors.
- hlMllUlhl
nMnw nurnKxy
Temperature
Baramebic pressure
R.H.
T
%
«C
mmHg
Could allect the mowamsnt, dMusion, and concentration of
VOCs; IntsmMed factors' could be site soedfc and
upon sol surface - air inlsriace dWsrertWs.
Chiou and Sho«4)(190S)
» >
vWIO^MQ
Groundcower
RelMant to speed, movement, and concenMion of
VOOsexpooed, removed, or dMusing torn sol surfaoe.
¦WKji nBUfv} VM MHO, W QMnDUNA 01 OOVp
could sAect movement, dMusionnlss, and
concentration of VOCs.
4
-------
TABLE 3. CHEMICAL PROPERTIES OF SELECTED VOLATILE ORGANIC COMPOUNDSf
Compound
Acetone
Benzene
Bromodichloromethane
Bromoform
Bromomethane
2-Butanone
Carbon disulfide
Carbon tetrachloride
Chlorobenzene
Chloroethane
2-Chloroethylvinyl ether
Chloroform
Chloromethane
Dibromochloromethane
1.2-Dichlorobenzene
1.3-Dichlorobenzene
1.4-Dichlorobenzene
1.1-Dichloroethane
1.2-Dichloroethane
1.1-Dichloroethene
trans-1,2-Oichloroethene
1.2-Dichloropropane
cis-1,3-Dichloropropene
trans-1,3,-Dichloropropene
Ethylbenzene
2-Hexanone
Methylene chloride
Methytisobutylketone
Perchloroethyiene
Styrene
1,1,2,2-Tetrachloroethane
Tetrachlcroethene
Toluene
1.1.1-Trichloroethane
1.1.2-Trichloroethane
Trichloroethylene
T richlorofluoromethane
Vinyl acetate
Vinyl chloride
Total xylenes
m.w.
(9/mole)
56
78
164
253
95
72
76
154
113
65
107
Solubilities
(mg/L <§> 20°C)
MisciUe
1760
7500
3190 (@30°)'
900
270000
2300
800
500
5740
toflK
1.91
2.18
1.34
1.56
1.80
2.04
2.18
1.40
-0.22
2.11
2.10
1.19
026
2.64
2.84
1.54
-0.24
0.22
1.50
0.94
0.16
0.61
Vapor Pressure
(mm @ 20°C)
270 (@30°)
76
50
6 (@25°)
1250
76
260
90
9
1000
120
51
8000
1.46
1.97
0.12
160
8348
0.78
0.91
1.62
3800
208
3300
2.45
224

15 (@10.5°)
147
100
2.62
3.38

1
147
123 (@25°)

3.38

147
49 (@ 22°)

3.39

1
99
5500
1.66
1.79
0.18
180
99
8690
1.34
1.48
0.04
61
97
400

500
97
600
1.56
2.06

20Q (@ 14°)
113
2700

1.99

42
110
2700

34 (@25°)
111
2800

43 (@25°)
106
152
2.60
3.15

7
100
3500

1.38

2
85
20000
1.40
1.25

349
100
17000
1.34
1.46
0.002
6
166
150
2.60
2.60
0.85
14
104
300
2.61
2.95

5
168
2900
2.07
2.60

5
166
150
2.78
3.40

18 (@25°)
92
515
2.18
2.69
0.27
22
133
4400
2.19
2.50
1.46
100
133
4500
2.14
2.07

19
132
700
2.09
2.29
0.37
60
137
1100 (@25°)
2.68

687
86
25000
1.59
0.73

115 (0251
63
1100(025°)
2.60
1.38
97.0
2660 (92Sa)
106
198
2.46

9400.0

' From Vwachutftn 1983, Jury 1964.
* urguK ctrDon pt/ivonuiQ ootisotnt
* OdanoMralsrpartNloningoosMcisnL
* HswyfrQis Law constant (limsnslonlsss) fr 20«C.
5
Lt.
-------
TABLE 4. MICROBIOLOGICAL FACTORS AFFECTING VOCs IN SOIL SYSTEMS
Organism(i)
Compound^)
Conditions Remarks/metabolites)
Various soil microbes Pentachlorophenol
Aerobic tetra-, tri-, di-, and m-Chlorophenol (Kobayashi and Rittman, 1 9q2)
1,2,3- and 1,2,4-Trichlorobenzene Aerobic 2,6-; 2,3-Dichlorobenzene; 2,4- and 2,5-dichlorobenzene; CO
(Kobayashi and Rittman, 1982) '
Various soil bacteria
Trichloroethane, trichloromethane, Anaerobic
methytehtoride, chloroethane,
dichloroethane, vinytidiene chloride,
trichloroethene, tetrachloroethene,
methylene chloride,
dibromochloromethane,
bromochloromethane
Reductive dehalogenation under anoxic conditions, (i.e., < 0.35 V)
(Kobayashi and Rittman, 1982)
Various soil microbes Tetrachloroethene
Anaerobic Reductive dehalogenation to trichloroethene,dichloroethene, and
vinyl chloride, and finally CO, (Vogel and McCarty, 1985)
Various soil microbes "C-labeled trichloroethene
Anaerobic Dehalogenation to 1,2-dfehloroethene and not 1,1-dichlofoethene
(Kleopferetal., 1985)
Various soil bacteria Trichloroethene
Aerobic Mineralized to C02 in the presence of a mixture of natural gas
and air
Actinomycetes
chlorinated and non-chlorinated
aromatics
aerobic Various particle breakdown products mineralized by other
microorganisms (Lechevalier and Lechevalier, 1976)
Fungi
DDT
Aerobic Complete mineralization in 10-14 days (Johnsen, 1976)
Pseudomonassp.
Acinetobactersp.
Micrococcus sp.
Aromatics
Aerobic Organisms were capable of sustaining growth in these compounds
with 100% biodegradation (Jamison et at.. 1975)
Acetate-grown biofilm Chlorinated aUphatics
Chlorinated and nonchlorinated
aromatics
Aerobic No biodegration observed (Bouwer, 1984)
Methanogenic Nearly 100% biodegradation observed (Bouwer, 1984)
Aerobic Nearly 100% biodegradation (Bouwer, 1984)
Methanogenic No biodegration observed (Bouwer, 1984)
Blue-green algae
(cyanobacteria)
Oil wastes
Aerobic Biodegradation of automobile oil wastes, crankcase oil, etc.
(Cameron, 1963)
6
-------
partitioning is favored when moisture content is higher (Chiou
and Shoup, 1985).
Biological factors affecting VOC retention in soil systems can be
divided into microbiological and macrobiological factors. On the
microbiological level, the indigenous microbial populations
present in soil systems can alter VOC concentrations. Although
plants and animals metabolize a diversity of chemicals, the
activities of the hinhor— '
, inButDoiize a oiversity of chemicals, the
activities of the higher organisms are often minor compared to
the transformations affected by heterotrophic bacteria and fungi
residing in the same habitat. The interactions between environ-
mental factors, such as dissolved oxygen, oxidation-reduction
potential (Eh), temperature, pH, availability of other compounds,
salinity, particulate matter, and competing organisms, often
control biodegradation. The physical and chemical characteris-
tics of the VOC, such as solubility, volatility, hydrophobicity, and
K„, also influence the ability of the compound to biodegrade.
Table 4 illustrates some examples of the microbiological alter-
ations of some commonly encountered soil VOCs. In general,
the halogenated alkanes and alkenes are metabolized by soil
microbes under anaerobic conditions (Kobayashi and Rittman,
1982; Bouwer, 1984), whereas the halogenated aromatics are
metabolized under aerobic conditions. To avoid biodegradation
and oxidation of VOCs in soils, scientists at the U.S. EPA Robert
S. Kerr Environmental Research Laboratory in Ada, OK, extrude
the sample in a glove box.
On a macro scale, biological factors can influence the migration
of VOCs in the saturated, vadose, and surface zones (Table 5).
Biofilms may accumulate in the saturated zone and may biode-
grade and bioaccumulate VOCs from the ground water. The
biofilm, depending on its thickness, may impede ground-water
flow. Plant roots have a complex microflora associated with
TABLE 5. MACROBIOLOGICAL FACTORS AFFECTING VOCs
IN SOIL SYSTEMS
Factor
Zone
Effects
Biofilms
Saturated
Biodegradation, bioaccumulation,
formation of metabolites that are
more or less toxic than parent
compound, thick biofilm may
retard saturated Dow
Plant roots
Capillary fringe
to vadose
Mycorrihtzal fungi may biodegrade
or bioaccumulate VOC, root
channels may serve as conduits
for VOC migration
Animal burrows
holes
Vadose
May act as entry point for and
downward migration of surface
spills and serve as conduit for
upward VOC migration
Vegetative cover
Soil surface
Serve as barrier to volatilization
from soil surface and retard
infiltration of surface spills
wISU known as roycorrhizae. The mycorrhizae may enhance
VOC retention in the soil by biodegradation or bioaccumulation.
The root channels may act as conduits for increasing the
migration of VOCs through the soil. Similarly, animal burrows
and holes may serve as paths of least resistance for the
movement of VOCs through soil. These holes may range from
capillary-size openings, created by worms and nematodes, to
large-diameter tunnels excavated by burrowing animals. These
openings may increase the depth to which surface spills pen-
etrate the soil. A surface covering consisting of assorted vegeta-
tion is a significant barrier to volatilization of VOCs into the
atmosphere. Some ground-water and vadose-zone models
(e.g., RUSTIC) include subroutines to account for a vegetative
cover (Dean et a!., 1989).
SOIL SAMPLING AND ANALYSIS DESIGN
Prior to any sampling effort, the RPM or OSC must establish the
intended purpose of the remedial investigation/feasibility study
(RI/FS). The goals of collecting samples for VOA may include
source identification, spill delineation, fate and transport, risk
assessment, enforcement, remediation, or post-remediation
confirmation. The intended purpose of the sampling effort drives
the selection of the appropriate sampling approach and the
devices to be used in the investigation.
The phase partitioning of the VOC can also influence which
sampling device should be employed. Computer models gener-
ally are used only at the final stages of a RI/FS. However,
modeling techniques can be used throughout the RI/FS process
to assist in sampling device selection by estimating the phase
partitioning of VOCs. The RPM is the primary data user for a Rl/
FS led by a federal agency. As such, the RPM must select the
sampling methodology to be employed at the site. Figure 2
illustrates the sequence of events used to plan a VOC sampling
and analysis activity.
The domains of interest also must be determined. The target
domains may include surface (two dimensions) or subsurface
(three dimensions) environments, hot spots, a concentration
greater or less than an action limit, or the area above a leaking
underground storage tank. Statistics that may be generated
from the target domain data must be considered before a
sample and analysis design is developed. Possible statistics of
interest may include average analyte concentration and the
variance about the mean (statistics that compare whether the
observed level is significantly above or below an action level) as
well as temporal and spatial trends. Data must be of sufficiently
high quality to meet the goals of the sampling activity. The level
of data quality is defined by the data quality objectives (DQOs).
In RI/FS activities, site* are so different and information on
overall measurement error (sampling plus analytical error) is so
limited that it is not practical to set universal or generic precision,
accuracy, representativeness, completeness, and comparabil-
ity (PARCC) goals. The reader is referred to a user's guide on
quality assurance in soil sampling (Barlh et al., 1989) and a
guidance document for the development of data quality objec-
tives for remedial response activities (U.S. EPA, 1987).
DQOs are qualitative and quantitative statements of the level of
uncertainty a decision maker is willing to accept in making
decisions on the basis of environmental data. It is important to
realize that if the error associated with the sample collection or
7
-------
DEFINE 1
GOAL
1
• Soil population

* Location
I
• Statistics
I
• Trend

• x, Std. dev.

• Comparison

• Purpose

• Enforcement

• Remediation

• Source ID

1
r
CHARACTERIZE

SITE

ANALVTF
• History
• Process
• Soil properties
• Soil conditions
• Existing data
• Environmental
factors
-W
OF INTEREST

SET
DQOs
~ DESIGN
MINIMIZF RESOURCE S
SELECT
TOOLS
Split spoon
Piston samplers
Zero contam.
sampler
Shelby tube
Veihmeyer tube
Shovels
MAXIMIZE INFORMATION MAXIMIZE QUALITY
NO
FEASIBLE
^ YES
Refine draft S&A Plan
to meet goals

ON-SITE
DATA
• Field analysis
• Odors 1
• Visual
• Population I
observations
accesibility 1
CONSTRAINTS
Personnel
Budget
Time
Politics
FIELD
IMPLEMENTATION
DATA EVALUATION
URAET
S& A PLAN
Tools
Analytical methods
Holding times
No. of samples
Sample mass
Decontamination
QA/QC
Field analysis
Handling
Random/
systematic design
OBJECTIV
MET
NO
Figure 2. Flowchart for planning and implementation of a soil sampling and analysis activity.
8
-------
preparation step is large, then the best laboratory quality
assurance program will be inadequate (van Ee et al„ 1990).
The greatest emphasis should be placed on the-phase that
contributes the largest component of error. For the analysis of
soils for VOCs, the greatest sources of error are the sample
collection and handling phases.
The minimum confidence level (CL) required to make a
decision from the data is defined by the DQOs. The minimum
CL depends on the precision and accuracy in sampling and
analysis and on the relative analyte concentration. Relative
error may be reduced by increasing either the number or the
mass of the samples to be analyzed. For instance, although
5-g aliquots collected in the field might exhibit unacceptable
errors, 100-g samples will yield smaller errors and might
therefore meet study or project requirements. Compositing soil
samples in methanol in the field also can reduce variance by
attenuating short-range spatial variability.
Field sampling personnel should coordinate with laboratory
analysts to ensure that samples of a size appropriate to the
analytical method are collected. For example, if the laboratory
procedure for preparing aliquots calls for removing a 5-g
aliquot from a 125-mL wide-mouth jar, as per SW-846, Method
8240 (U.S. EPA 1986b), then collecting a larger sample in the
field will not reduce total measurement error, because addi-
tional errors will be contributed from opening the container in
the laboratory and from subsequent homogenization.
Aliquoting of a 5-g sample in the field into a 40-mL VOA vial that
can be directly attached to the laboratory purge-and-trap unit
significantly reduces loss of VOCs from the sample (U.S. EPA,
1991a). Significant losses of VOCs were observed when
samples were homogenized as per Method 8240 specifica-
tions. Smaller losses were observed for smaller aliquots (1 to
5 g) placed in 40-mL VOA vials that had modified caps that
allowed direct attachment to the purge-and-trap device. The
procedure of collecting an aliquot in the field eliminates the
need for sample preparation and eliminates subsequent VOC
loss in the laboratory.
Field-screening procedures are gaining recognition as an
effective means of locating sampling locations and obtaining
real-time data. The benefits of soil field-screening procedures
are: (1) near real-time data to guide sampling activities, (2)
concentration of Contract Laboratory Program (CLP) sample
collection in critical areas, (3) reduced need for a second visit
to the site, and (4) reduced analytical load on the laboratory.
Limitations of field-screening procedures are: (1) a priori
knowledge of VOCs present at the site is needed to accurately
identify the compounds, (2) methodologies and instruments
are in their infancy and procedures for their use are not well
documented and (3) a more stringent level of quality assur-
ance and quality control (QA/QC) must be employed to ensure
accurate and precise measurements. The potential benefits
and limitations associated with soil-screening procedures
must be carefully weighed and compared to the DQOs.
Certain sampling and analytical methods have inherent limita-
tions on the type of QA/QC that is applicable. For example,
splitting soil samples in the field would not be appropriate for
VOA due to excessive analyte loss. The higher the minimum
CL needed to make a decision, the more rigorous the QA/QC
protocols must be. As VOC concentrations in the soil sample
approach the action or detection limit, the quantity and fre-
quency of QA/QC samples must be increased, or the number of
samples must be increased, to ensure that the data quality
obtained is appropriate to satisfy project objectives.
One critical element in VOC analysis is the appropriate use of trip
blanks. If a sample consists of a silty day loam, a trip blank of
washed sand may not be realistic, for such a blank would not
retain VOC cross contaminants in the same way as the sample.
The trip blank soil matrix should have a sorptive capacity
similar to the actual sample. In addition, high-
concentration and low-concentration samples should be shipped
in separate coolers.
DEVICE SELECTION CRITERIA
The selection of a sampling device and sampling procedures
requires the consideration of many factors including the number
of samples to be collected, available funds, soil characteristics,
site limitations, ability to sample the target domain, whether or not
screening procedures are to be used, the size of sample needed,
and the required precision and accuracy as given in the DQOs.
The number of samples to be collected can greatly affect sam-
pling costs and the time required to complete a site characteriza-
tion. If many subsurface samples are needed, it may be possible
to use soil-gas sampling coupled with on-site analysis as an
integrated screening technique to reduce the area of interest and
thus the number of samples needed. Such a sampling approach
may be applicable for cases of near-surface contamination.
Ultimately, the sampling, sample handling, containerizing, and
transport of the soil sample should minimize losses of volatiles
and should avoid contamination of the sample. Soil sampling
equipment should be readily decontaminated in the field if it is to
be reused on the job site. Decontamination of sampling equip-
ment may require the use of decontamination pads that have
impervious liners, wash and rinse troughs, and careful handling
of large equipment Whenever possible, a liner should be used
inside the sampling device to reduce potential cross contamina-
tion and carryover. Decontamination procedures take time,
require extra equipment, and ultimately increase site character-
ization costs. Ease and cost of decontamination are thus impor-
tant factors to be considered in device selection.
Several soil-screening procedures are in use that include
headspace analysis of soils using organic vapor analyzers: water
(or NaCI-saturated water) extraction of soil, followed by static
headspace analysis using an organic vapor analyzer (OVA) or
gas chromatograph (GC); colorimetric test kits; methanol extrac-
tion followed by headspace analysis or direct injection into a GC;
and soil-gas sampling (U.S. EPA, 1988). Field measurements
may not provide absolute values but often may be a superior
means of obtaining relative values. These procedures are gain-
ing acceptance.
Site Characteristics
The remoteness of a site and the physical setting may restrict
access and, therefore, affect equipment selection. Such factors
as vegetation, steep slopes, rugged or rocky terrain, overhead
power lines or other overhead restrictions, and lack of roads can
contribute to access problems.
The presence of underground utilities, pipes, electrical lines,
tanks and leach fields can also affect selection of sampling
9
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equipment. If the location or absence of these hazards cannot
be established, it is desirable to conduct a nonintrusive survey
of the area and select a sampling approach that minimizes
hazards. For example, hand tools and a backhoe are more
practical under such circumstances than a large, hollow-stem
auger. The selection of a sampling device may be influenced by
other contaminants of interest such as pesticides, metals,
semivolatile organic compounds, radionuclides, and explo-
sives. Where the site history indicates that the matrix is other
than soil, special consideration should be given to device
selection. Concrete, reinforcement bars, scrap metal, and lum-
ber will affect sampling device selection. Under some circum-
stances, it may not be practical to collect deep soil samples. The
presence of ordnance, drums, concrete, voids, pyrophoric ma-
terials, and high-hazard radioactive materials may preclude
some sampling and may require development of alternate
sampling designs, or even reconsideration of project objectives.
Soil Characteristics
The characteristics of the soil material being sampled have a
marked effect upon the selection of a sampling device. An
investigator must evaluate soil characteristics, the type of VOC,
and the depth at which a sample is to be collected before
selection of a proper sampling device. Specific characteristics
that must be considered are:
1. Is the soil compacted, rocky, or rubble filled? If the answer
is yes, then either hollow stem augers or pit sampling must
be used.
2. Is the soil fine grained? If yes, use split spoons, Shelby
tubes, liners, or hollow stem augers.
3. Are there flowing sands or water saturated soils? If yes, us»
samplers such as piston samplers that can retain these
materials.
SOIL-GAS MEASUREMENTS
Soil-gas measurements can serve a variety of screening pUr,
poses in soil sampling and analysis programs, from initial site
reconnaissance to remedial monitoring efforts. Soil-gas mea-
surements should be used for screening purposes only, and not
for definitive determination of soil-bound VOCs. Field analysis
is usually by hand-held detectors, portable GC or GC/Ms
infrared detectors, ion mobility spectrometers (IMS), industrial
hygiene detector tubes, and, recently, fiber optic sensors.
At some sites, soil-gas sampling may be the only means of
acquiring data on the presence or absence of VOCs in the soil
For example, when the size and density of rocks and cobbles
at a site prevent insertion and withdrawal of the coring device
and prevent sampling with shovels and trowels, unacceptable
losses of VOCs would occur. Soil-gas measurements, which
can be made on site or with collected soil samples, can be "tor]
to identify volatile contaminants and to determine relative
magnitudes of concentration. Smith et al. (1990) have shown
a disparity in soil-gas VOC concentrations and the concentra-
tion of VOCs found on the solid phase.
Soil-gas measurements have several applications. These in-
clude in situ soil-gas surveying, measurement of headspace
concentrations above containerized soil samples, and scan-
ning of soil contained in cores collected from different depths'
These applications are summarized in Table 6. Currently, Rq
TABLE 6. APPLICATIONS OF SOIL-GAS MEASUREMENT TECHMQUES IN SOIL SAMPLING FOR VOCa
AppHcrion Uses Methods BemfHs/UmiMions
Soil vapor
surveying
Identify sources and extent
of contamination. Distinguish
between soil and ground water
contamination. Meet VOCs
under asphalt, concrete, etc.
Active sampling from soil probes
into canisters, glass bulbs, gas
sampling bags. Passive sampling
onto buried adsorptive substrates.
Followed by GC or other analysts.
BENEFITS: Rapid, inexpensive screening of
large areas, avoid sampling uncontaminated areas.
LIMITATIONS: False positives and negatives, miss
delecting localized surface spis, disequilibrium
between adsorbed and vapor phase VOC
concentrations.
Soil headspace
measurements
Screen large numbers of soil
samples.
Measure headspace above
containerized soil sample.
Containers range from plastic
sandwich bags to VOA vials.
Use GC, vapor detectors, IMS, etc.
BENEFITS: More representative of adsoibed solid
phase concentration.
LIMITATIONS: Losses of vapor phase component
during sampling and sample transfer.
Screening
soil cores
Soil cores scanned to locate
depth where highest VOC
levels are located.
Collect core sample (e.g., uniined
split spoon) and scan for vapors near
core surface using portable vapor
monitor.
BENEFITS: Locate and collect soil from hot spot
in core for worst case.
LIMITATIONS: False negatives and positives,
environmental conditions can influence readings
(e.g., wind speed and direction, temperature, humidity).
10
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standard protocols exist for soil-gas analysis; many investiga-
tors have devised their own techniques, which have varying
degrees of efficacy. Independently, the American Society for
Testing and Materials (ASTM) and EPA EMSL-LVare preparing
guidance documents for soil-gas measurement. These docu-
ments should be available late in 1991.
The required precision and accuracy of site characterization, as
defined in the DQOs, affect the selection of a sampling device.
Where maximum precision and accuracy are required, sampling
devices that collect an intact core should be used, particularly for
more volatile VOCs in nonretentive matrices. Augers and other
devices that collect highly disturbed samples and expose the
samples to the atmosphere can be used if lower precision and
accuracy can be tolerated. Collection of a larger number of
samples to characterize a given area, however, can compen-
TABLE7.
sate for a less precise sampling approach. The closer the
expected contaminant level is to the action or detection limit, the
more efficient the sampling device should be for obtaining an
accurate measurement.
SOIL SAMPLING DEVICES
Table 7 lists selection criteria for different types of commercially
available soil sampling devices based on soil type, moisture
status, and power requirements. The sampling device needed
to achieve a certain sampling and analysis goal can be located
in Table 7 and the supplier of such a device can be identified in
Table 8. Table 8 is a partial list of commercially available soil
sampling devices that are currently in use for sampling soils for
VOC analysis. The list is by no means exhaustive and inclusion
(Continued on page 14)
°£Mn* J**, Operation Suitable Soil fWatfv* labor Manual
Twn. m cohesive.
11
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TABLE 8. EXAMPLES OF COMMERCIALLY AVAILABLE SOIL SAMPLING DEVICES
Manuteeturers
Sampling Device
Specifications
Length (Inches)
I.D. (inches)
Sampler Material Unart
Features
Associated Design &
Manufacturing Co.
814 North Henry Street
Alexandria, VA 22314
703-549-5999
Purge and Trap
Soil Sampler
3
0.5
Stainless steel
Will rapidly sample soils
for screening by "Low LeveT
Purge and Trap methods.
Acker DriN Co.
P.O. Box 830
Scranton, PA
717-586-2061
Heavy Duty "Lynac*
Split Tube Sampler
Dennison Core Barrel
18&24
1-1/2 to 4-1/2
Steel
24&60
1-7/8 to 6-5/16
Brass,
Brass
Split tube allows for easy
sample removal.
Will remove undisturbed
sample from cohesive soils.
AMS
Harrison at Oregon Trail
American Fads, ID 83211
Core Soil Sampler
Dual Purpose Soil
Recovery Probe
Soil Recovery Auger
2 to 12
1-1/2 to3
Alloy, stainless
12,18&24
3/4 and 1
4130 Alloy,
8 to 12
2&3
Stainless
Stainless, plastic
aluminum, bronze
teflon
Butyrate, Teflon
Plastic, stainless
Teflon, aluminum
Good in aU types of soils.
Adapts to AMS'up & down'
hammer attachment. Use
with or without liners.
Adaptable to AMS extension
and cross-handles.
Concord, Inc.
2800 7th Ave. N.
Fargo, ND 58102
701-280-1260
Speedy Soil Sampler
Zero Contamination Unit
Hand-Held Sampler
48472
3/16 to 3-1/2
Stainless
Acetate
Automated system allows
retrieval of 24 in soil
sample in 12 sec.
CME
Central Mine Equip. Co.
6200 North Broadway
St. Louis, MO 63147
800-325-8827
Continuous Sampler
60
2-1/2 to 5-3/8
Steel, stainless
Bearing Head Continuous 60
Sample Tube System 2-1/2
Steel, stainless
Butyrate
Butyrate
May not be suitable in
stony soils. Adapts to CMS
auger.
Versatile system. Adapts
to all brands of augers.
Diedrich Drilling Equip.
P.O. Box 1670
Laporto, IN 46350
800-348-8809
Heavy Duty Split
Tube Sampler
Continuous Sampler
18&24
2.2-1/2,3
Steel
60
3.3-1/2
Brass, plastic
stainless,Teflon
Brass, plastic
stainless, Teflon
Full line of accessories
a/e available.
Switch-out device easily
done.
12
(Continued)
-------
TABLES. (CONTINUED)
Specifications
Length (inches)
I.D. (Inches)
Manufactures Sampling Device Sampler Material Liners Features
Geoprobe Systems
607 Barney St.
Salina, KS
913-825-1842
Probe Drive
Soil Sampler
11-1/4
0.96
Alloy steel
Remains completely sealed
while pushed to depth in
soil.
Giddings Machine Co.
P.O. Drawer 2024
Fort Collins, CO 80522
303-485-5586
Coring Tubes
48&60
7/8 to 2-3/8
4130 Molychrome
Butyrate
A series of optional 5/8 in
slots permit observation of
the sample.
JMC
Clements and Associates
R.R. 1 Box 186
Newton, IA 50208
800-247-6630
Environmentalist's
Sub-soil Probe
Zero Contamination
Tubes
36&48
Q.9
Nickel plated
12,18 & 24
0.9
Nickel plated
PETG plastic,
stainless
PETG plastic,
Adapts to drop-hammer to
penetrate the hardest of soils.
Adapts to power probe.
Mobile Drilling Co.
3807 Madison Ave.
Indianapolis, IN 46227
800-428-4475
"Lynac" Split
Barrel Sampler
18&24
1-1/2
Brass,
plastic
Adapts to Mobile wireline
sampling system.
Solitest, Inc.
66 Albrecht Drive
Lake Bluff, IL
800-323-1242
Zero Contamination
Sampler
Thin Wall Tube
Sampler (Shelby)
12,18 & 24
0.9
Chrome plated
30
2-1/2,3,3-1/2
Steel
Stainless,
Hand sampler good for
chemical residue studies.
Will take undisturbed samples
in cohesive soils and clays.
Split Tube Sampler
Veihmeyer Soil
Sampling Tube
24
1-1/2 to3
Steel
48&72
3/4
Steel
Forced into soil by jacking,
hydraulic pressure or driving.
Very popular type of sampler.
Adapts to drop hammer for
sampling in ail sorts of soils.
Sprague & Henwood, Inc.
Saanton, PA 18501
800-344-8506
S & H Split Barrel
Sampler
18424
2 to 3-1/2
Brass,
plastic
A general all-purpose
sampling device designed
for driving into material to
be sampled.
Note: This tot is not exhaustive. Inclusion in this 1st should not be consbued as endorsement lor use.
13
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in the list should not be construed as an endorsement for their
use.
Commonly, soil samples are obtained from the near surface
using shovels, scoops, trowels, and spatulas. These devices
can be used to extract soil samples from trenches and pits
excavated by back hoes. A predeaned shovel or scoop can be
used to expose fresh soil from the face of the test pit. A thin-
walled tube or small-diameter, hand-held corer can be used to
collect soil from the exposed face. Bulk samplers such as
shovels and trowels cause considerable disturbance of the soil
and expose the sample to the atmosphere, enhancing loss of
VOCs. Siegrist and Jenssen (1990) have shown that sampling
procedures that cause the least amount of disturbance provide
the greatest VOC recoveries. Therefore, sampling devices that
obtain undisturbed soil samples using either hand-held or me-
chanical devices are recommended. Sampling devices that
collect undisturbed samples include split-spoon samplers, ring
samplers, continuous samplers, zero-contamination samplers,
and Shelby tubes. These sampling devices can be used to
collect surface soil samples or they can be used in conjunction
with hollow-stem augers to collect subsurface samples. The soil
sampling devices discussed above are summarized in Table 9.
Devices where the soil samples can be easily and quickly
removed and containerized with the least amount of disturbance
and exposure to the atmosphere are highly recommended. U.S.
EPA (1986a) gives a more detailed discussion on the proper use
of drill rigs and sampling devices.
Liners are available for many of the devices listed in Table 9.
Liners make soil removal from the coring device much easier
and quicker. Liners reduce cross contamination between
samples and the need for decontamination of the sampling
device. The liner can run the entire length of the core or can be
precut into sections of desired length.
When sampling for VOCs, it is critical to avoid interactions
between the sample and the liner and between the sample and
the sampler. Such interactions may include either adsorption of
VOCs from the sample or release of VOCs to the sample.
Gillman and O'Hannesin (1990) studied the sorption of six
monoaromatic hydrocarbons in ground water samples by seven
materials. The hydrocarbons included benzene, toluene,
ethylbenzene, and o-, m-, and p-xylene. The materials exam-
ined were stainless steel, rigid PVC, flexible PVC, PTFE Teflon,
polyvinylidene fluoride, fiberglass, and polyethylene. Stainless
TABLE 9. SOIL SAMPLERS FOR VOC ANALYSIS
Not Recommended
Split spoon w/liners
Shelby tube (thin wall tubes)
Holow-stem augers
Vejhmtyer or King tubes
w/Bners
Piston samplers'
Zero contamination samplers*
Probe-drive samplers
Solid flight liners
DriNing mud auger
Air driRing auger
Cable tool
Hand augers
Barrel augers
Scoop samplers
Excavating tools, e.g., shovels, backhoes
* May sustain VOC losses if not used with care
steel showed no significant sorption during an 8-week period. All
polymer materials sorbed all compounds to some extent. The
order of sorption was as follows: rigid PVC < fiberglass ^
polyvinylidene fluoride < PTFE < polyethylene < flexible PVc
Stainless steel or brass liners should be used since they exhibit
the least adsorption of VOCs. Other materials such as PVC or
acetate may be used, provided that contact time between the
soil and the liner material is kept to a minimum. Stainless steel
and brass liners have been sealed with plastic caps or paraffjn
before shipment to the laboratory for sectioning and analysis
VOC loss can result from permeation through the plastic or
paraffin and volatilization through leaks in the seal. Acetate
liners are available, but samples should not be held in these
liners for any extended period, due to adsorption onto and
permeation through the material. Alternatively, the soil can be
extruded from the liner, and a portion can be placed into a wide-
mouth glass jar. Smaller aliquots can be taken from the center
of the precut liner using subcoring devices and the soil piuQ
extruded into VOA vials.
TRANSFER OF SOIL SAMPLES FROM DEVICE TO
CONTAINER
The sample transfer step is perhaps the most critical and least
understood step in the sampling and analysis procedure. The
key point in sample transfer, whether in the field or in the
laboratory, is to minimize disturbance and the amount of time the
sample is exposed to the atmosphere. It is more important to
transfer the sample rapidly to the container than to accurately
weigh the aliquot which is transferred, or to spend considerable
time reducing headspace. Therefore, a combination of a device
for obtaining the appropriate mass of sample and placement of
the aliquot into a container that can be directly connected to the
analytical device in the laboratory is recommended. Several
designs are available for obtaining a 5-g aliquot (or other size).
Most subcoring devices consist of a plunger/barrel design with
an open end. The device shown in Figure 3 was constructed by
Associated Design & Manufacturing Company (Alexandria
VA). Other designs include syringes with the tips removed, and
cork borers (Table 8). The device is Inserted into the sample and
an aliquot is withdrawn. The aliquot, which is of a known volume
and approximate weight, can then be extruded into a tared 40-
mL VOA vial. Routinely, the vial is then sealed with a Teflon-lined
septum cap. Teflon, however, may be permeable to VOCs.
Aluminum-lined caps are available to reduce losses due to
permeation. At the laboratory, the vial must be opened and the
contents of the vial must be transferred to a sparger tube. The
transfer procedure will result in significant losses of VOCs from
the headspace in the vial. The modified purge-and-trap cap
shown in Figure 4 eliminates the loss of VOCs due to container
opening and sample transfer. The soil is extruded from the
subcorer into a tared 40-mL VOA vial and the modified cap is
attached in the field. In the laboratory, the vial is attached directly
to a purge-and-trap device without ever being opened to the
ambient air.
Use of subcoring devices should produce analytical results of
increased accuracy. In order to test this hypothesis, an experi-
ment was conducted in which a bulk son sample was spiked with
800 ng/kg of different VOCs (Maskarlnec, 1990). Three aliquots
were withdrawn by scooping, and three aliquots were withdrawn
by using the sub-corer approach. The results are presented in
Table 10. Although neither method produced quantitative recov-
ery, the subcorer approach produced results that were generally
14
-------
Figure 3. Small-diameter hand-held subcoring device made
by Associated Design & Manufacturing Company
(Alexandria, VA).
TABLE 10. LABORATORY COMPARISON OF STANDARD METHOD
AND SUBCORER METHOD

Standard

Method
Subcorer

% of
%of

Standard
Subcorer
Recovery
Recovery
Compound
Method*
Method"
of Spike
of Spike
Chloromethane
50
1225
6
153
Bromomethane
31
536
4
67
Chloroethane
78
946
10
118
1,1-Dichloroethene
82
655
10
82
1,1-Dichloroethane
171
739
21
92
Chloroform
158
534
20
67
Carbon tetrachloride
125
658
16
82
1,2-Dichloropropane
147
766
18
96
Tnchloroethene
120
512
15
64
Benzene
170
636
21
80
1,1,2-Trichloroethane
78
477
10
60
Bromoform
30
170
4
21
1,1,2,2-Trichloroethane
48
271
6
34
Toluene
129
656
16
82
Chlorobenzene
57
298
7
37
Ethylbenzene
68
332
8
42
Styrene
30
191
4
24
five times higher than the standard approach, whereby the
contents of a 125-mL wide-mouth jar are poured into an alumi-
num tray and homogenized with a stainless steel spatula. A 5-
g sample is then placed in the sparger tube (SW-846, Method
8240). Several compounds presented problems with both
approaches: styrene polymerizes, bromoform purges poorly,
and 1,1,2,2-tetrachloroethane degrades quickly.
1/2" Stainless
Steel Body
O-Ring
1/16"
Teflon Ball
Receiving union from
Purge-and-Trap Device
1/2" Stainless
Steel Body
O-Ring
Hole Cap
40 mL Vial
Purge Needle
• n)/kg(n»3)
b M0*g (n-3)
Note. Standard method of sample transfer consists ol scooping and subcorer
method uses device shown in Figure 3. Soil samples were spiked with 800
ng/kg of each VOC.
Figure 4. Modified purge-and-trap 40-mL VOA vial cap for
containerizing samples in the field. Vial is
attached directly to a purge-and-trap system
without exposure of sample to the atmosphere.
15
-------
In another study (U.S. EPA, 1991a), a large quantity of well
characterized soil was spiked with 33 VOCs and was homog-
enized. From the homogenized material, a 5-g aliquot of soil was
placed in a 40-ml VOA vial and sealed with a modified purge-
and-trap cap (Figure 4). The remaining soil was placed in 125-
mL wide-mouth jars. The samples were shipped via air carrier
and were analyzed by GC/MS with heated purge and trap. The
40-mL VOA vials were connected directly to a Tekmar purge-
and-trap unit without exposure to the atmosphere. The wide-
mouth jars were processed as per SW-846 Method 8240 speci-
fications (U.S. EPA, 1986b). Table 11 compares the results of
the GC/MS analyses using the two pretreatment techniques.
The modified method (40-mL VOA vial with a modified cap)
yielded consistently higher VOC concentrations than the tradi-
tional Method 8240 procedure (U.S. EPA, 1986b).
The standard methods for VOC analysis, SW-846, Method 8240
and Test Method 624 (U.S. EPA, 1986b; U.S. EPA, 1982), call
for the containerizing of soil samples in 40-mL VOA vials or 125-
mL wide-mouth jars with minimal headspace. As previously
described, wide-mouth jars may not be the most appropriate
containers due to sample aliquoting requirements. Although
wide-mouth jars may be equally as effective as 40-mL VOA vials
in maintaining the VOC content of soil samples, the sample
preparation procedure that is required with jar-held samples
causes significant (>80%) loss of highly volatile VOCs (Siegrist
and Jennsen, 1990). However, if samples are collected in such
containers, it is important to ensure sample integrity, preferably
by using amber glass jars (for photosensitive compounds) with
solid phenolic resin caps and foam-backed Teflon liners. Alumi-
num-lined caps are not available for the wide-mouth jars. Soil
should be wiped from the threads of the jar to ensure a tight seal.
The methanol-immersion procedure calls for the transfer of the
sample into a glass jar containing a known volume of chromato-
graphic-grade methanol (usually 100 mL) or in a 1:1 weight-to-
volume ratio of soil to methanol. This has the effect of preserving
the volatile components of the sample at the time the sample is
placed in the container. Furthermore, surrogate compounds can
be added at this time in order to identify possible changes in the
sample during transport and storage. The addition of methanol
to the sample raises the detection limits from 5 to 10 iig/kg to 100
to 500 (ig/kg, because of the attendant dilution. However, the
resulting data have been shown to be more representative of the
original VOC content of the soil (Siegrist and Jennsen, 1990;
Siegrist, 1990). In a comparison of transfer techniques, Siegrist
and Jennsen (1990) demonstrated that minimum losses were
obtained by using an undisturbed sample followed by immediate
TABLE 11. COMPARISON OF VOC CONCENTRATIONS IN SPIKED SOIL ANALYZED BY METHOD 8240 AND MODIFIED METHOD 8240
Concentration (pg/kg)-
——Concentration (pg/kg>
VOC
Method
8240f
Method
8240ft
Difference VOC
Method
8240f
8240ft Difference
Bromomethane
9
44
35**
Dibromochloromethane
121
159
38
Vinyl chloride
3
32
29**
1,1,2-Trichloroethane
142
193
51
Chloroelhane
6
36
30"
trans-1,3-DicWoropropene
154
203
49
Methylene chloride
69
100
31**
Bromoform
116
140
24
Carton disulfide
32
82
50"
Tetrachloroethene
62
124
62"
1,1-Oichloroethene
12
35
23"
1,1,2,2-Tetrachloroethane
137
162
25
1,1-Dichloroethane
34
83
49"
Toluene
85
161
76*
1,2-DicNoroethene
36
66
30**
Ctilorobenzene
91
132
41"
Chloroform
56
96
40"
Ethylbenzene
85
135
50"
1,1,1-Trichloroettiane
26
80
54"
Stymie
86
114
28*
Carton tetrachloride
18
61
43"
Total xylenes
57
85
28"
Vinyl acetate
18
26
8

1,2-Dichloroethane
101
159
58"
KETONES

ds-1,3-Dichloropropene
136
189
53*
Acetone
336
497
161*
Trichkxoethene
48
87
39"
2-Butanone
290
365
75
Benzene
56
114
58*
2-Hexanone
200
215
15
BromodfcNoromelhane
111
166
55*
4-Methty-2-pentanone
264
288
24
t Metod 8240 using 125-mL wtdennoufc jar mixing suteamplng in laboratory purgeftap analysis,
ft Method 8240 using 40-mL vial. 5-g sampled in the Md, shipped to laboratory purge/trap analysts.
** Dillerence signifcantly greater than 0, with P-value <0.01.
* Dfflarence stgnifcartfy greater thsn 0, with P-vafcM between 0.01 and 0.05.
Note: Spfcs concentration was 300 nftg.
16
-------
immersion into methanol. The results for six VOCs are shown in
Figure 5. At high VOC spike levels (mg/kg) the investigators
found that headspace within the bottle caused a decrease in the
concentration of VOCs in the sample. At lower spike levels,
however, headspace did not seem to be a major contributor to
VOC losses (Maskarinec, 1990). In another study (U.S. EPA,
1991 a), it was found that a 5-g sample collected from a soil core
and placed in a 40-mL VOA vial provided consistently higher
TREATMENT A
UNDISTURBED SOIL
PLASTIC BAG
LOWHEADSPACE
treatment b
UNDISTURBED SOIL
GLASS JAR
HIGH HEADSPACE
treatment c
disturbed soil
GLASS JAR
LOW HEADSPACE
treatment D
UNDISTURBED SOIL
GLASS JAR
LOW HEADSPACE
TREATMENTE
UNDISTURBED SOIL
GLASS JAR
METHANOL
concentration, ppm
TREATMENT A TREATMENT B TREATMENT C TREATMENT D TREATMENT E
WM METHYLENE CHLORIDE M 1,2-DICHLOROETHANE
2J
concentration, ppm
1J
OJ

TREATMENT A
TREATMENTB
^ 1,1,1 ,-TRICHLOROETHANE
TOLUENE
TREATMENT C TREATMENT D
¦I TRICHLOROETHENE
¦H CHLOROBENZENE
TREATMENT E
Figure 5. VOC recovery as a function of sample treatment.
17
-------
VOC levels than a sample taken from the same core, placed in
a 125-mL wide-mouth jar, and later poured out, homogenized,
and a 5-g aliquot taken from the bulk material as per Method
8240 specifications.
SOIL SAMPLING SCENARIOS
The following recommendations for soil sampling and sample
handling are presented for the three general sampling sce-
narios described earlier.
1. Open Test Pit or Trench
Samples are often collected from exposed test pits or trenches
where remediation efforts are in progress. Sites may also be
encountered where large-diameter coring devices cannot be
employed. In such instances, crude sampling devices, such as
trowels, spoons, shovels, spades, scoops, hand augers, or
bucket augers must be used to excavate the soil.
The exposed face of an excavated test pit is scraped to uncover
fresh material. Samples are collected from the scraped face by
using a small-diameter, hand-held corer (Figure 3). If the
nominal 5-g sample is to be collected, the appropriate volume
(3 to 4 mL) is extruded into a tared 40-mL VOA vial and sealed
with a modified purge-and-trap cap (Figure 4). The vial is chilled
to 0° to 4®C and sent to the laboratory where the entire contents
of the vial are purged without opening the vial (U.S. EPA
1991b). Though this method minimizes losses of VOCs, the
small sample size may exhibit greater short-range spatial
variability than larger samples.
Alternatively, a small-diameter, hand-held soil corer (Figure 3)
can be used to collect a larger volume of soil. The soil is
extruded to fill a 40-mL VOA vial with a Teflon-lined septum cap
(minimal headspace), chilled, and sent to the laboratory. The
mayor weakness with this method is that VOCs are lost in the
laboratory during sample homogenization, preparation of
aliquots from a subsample, and the transfer to the extraction or
sparging device.
If large coarse fragments or highly compacted soils are encoun-
tered, the use of a hand-held corer may not be possible. In this
case crude sampling devices are used to rapidly collect and fill
(minimal headspace) a 125- or 250-mL wide-mouth glass jar.
The threads are wiped clean and the jar is sealed with a foam-
backed Teflon-lined cap. The jar is chilled immediately to 0° to
4°C for shipment to the laboratory. Losses of VOCs are consid-
erably greater with this method due to disruption of the matrix
and losses in the laboratory during sample preparation. Metha-
nol immersion may be more suitable for these matrices.
2. Surface Soils (< 5 ft deep)
The preferred soil sampling procedures reduce VOC losses by
minimizing sample disturbance during collection and transfer to
a container. The collection of soil cores with direct extrusion into
a container accomplishes this goal. A larger-diameter coring
device (e.g., split-spoon sampler, Shelby tube, zero-contami-
nation sampler) is used to collect an intact sample from the
surface soil or from an augered hole. Many of these samplers
can be used with liners, an insert that greatly reduces the time
required to remove the soil and obtain a subsample. For
subsamples collected from split spoons or extruded large-
diameter cores, the section to be subsampled is scraped and
laterally subcored, orthe extruded soil is cut or broken to expose
fresh material at the depth or zone of interest, then longitudinally
subcored. For large-diameter cores that are collected in precut
liners, the liner sections are separated with a stainless steel
spatula, and a small-diameter hand-held corer is used to collect
a subsample from the center of the liner section. The uppermost
portion of the core should not be sampled, because it is more
likely to be cross contaminated. The small diameter corer
(Figure 3) is pushed into the soil, the outside of the corer is wiped
clean, and the required core volume (typically about 3 to 4 mL
or 5 g) is extruded directly into a tared 40-mL glass VOA vial and
sealed with a modified purge-and-trap cap (Figure 4). The vial
threads and lip must be free of soil to ensure an airtight seal.
3. Subsurface soils (> 5 ft deep)
The same sampling principles apply for the collection of deeper
soil samples. Collection of soil cores with direct extrusion into a
container greatly reduces the loss of VOCs. Tube-type samplers
such as spiit-spoon, Shelby tubes, and zero-contamination
samplers are used inside a hollow-stem auger to obtain an intact
sample from greater depths. The coring device is retrieved and
a subsample is obtained in a similar manner as that described
for surface soils.
METHANOL IMMERSION PROCEDURE
Soil collected by protocols outlined above can be placed in a
tared wide-mouth glass jar containing pesticide-grade methanol
(1:1 weight-to-volume ratio of soil to methanol). The immersion
of relatively large soil samples into methanol has the advantage
of extracting a much larger sample that is probably less prone to
short-range spatial variability. This is of particular advantage
with coarse-grained soils, materials from which it is hard to
obtain a 1-g to 5-g subsample for analysis.
Multiple small-diameter corers can be immersed in a single
methanol-filled jar to produce a composite sample.
Compositing becomes practical because VOCs are soluble in
methanol, thus reducing losses. Appropriately collected com-
posite samples can produce more representative data than a
comparable number of individual samples. Short-range spatial
variability is greatly reduced. Another advantage is the ability to
reanalyze samples. The main disadvantages of using methanol
include the requirements for handling and shipping the metha-
nol and the detection limit that is raised by a factor of about 10
to 20. For the methanol-immersion procedure, jars filled with
methanol and shipped to the laboratory are classified as a
hazardous material, flammable liquid and must be labelled as
per Department of Transportation specifications (49 CFR,
1982). If these disadvantages are unacceptable, then the
modified purge-and-trap prooedure may be applicable.
FIELD STORAGE
Material containing VOCs should be kept away from the sample
and the sample container. Hand lotion, labeling tape, adhesives,
and ink from waterproof pens contain VOCs that are often
analytes of interest in the sample. Samples and storage contain-
ers should be kept away from vehicle and generator exhaust and
other sources of VOCs. Any source of VOCs may cause
contamination that may compromise the resulting data.
18
-------
Once samples are removed from the sampling device and
placed in the appropriate storage container, the containers
should be placed in the dark at reduced temperatures (0° to
4°C). Excessively cold temperatures (<-10°C) should be
avoided; studies have shown greater losses of analytes due to
reduced pressures in the container, sublimation of water, and
concomitant release of water-soluble VOCs into the headspace.
Upon opening the container, the vacuum is quickly replaced with
ambient air, thus purging out VOCs from the headspace
(Maskarinecetal., 1988). Extremely cold temperatures can also
loosen the seal on the container cap. Caps should be
retightened after 15 minutes at reduced temperatures. Samples
should be kept in ice chests while in route to the shipment facility
or laboratory. At temperatures above freezing, bacterial action
can have a significant impact on the observed soil VOC con-
centration. Numerous preservation techniques are being
evaluated at the University of Nevada Environmental Research
Center in Las Vegas and at Oak Ridge National Laboratory.
SHIPPING
Given the short holding times required for VOC analysis under
Method 8240 (10 days from sample collection to analysis),
samples are usually shipped via air carrier to the analytical
laboratory. Samples should be well packed and padded to
prevent breakage. Temperatures in cargo holds can increase to
more than 50°C during transit, therefore, the need for adequate
cold storage is critical. Styrofoam coolers are commercially
available to accommodate 40-mL and 125-mL glass containers.
Sufficient quantities of Blue Ice™ or Freeze-Gel™ packs should
be placed in the container to ensure that samples are cooled for
the duration of the shipment. A maximum-minimum thermom-
eter (non-mercury) should be shipped with the samples. If
sample containers are not adequately sealed, VOC losses can
occur. These losses may be exacerbated by the reduced
atmospheric pressures encountered in the cargo holds of air
carriers. Figure 6 illustrates the changes in temperature and
pressure in the cargo hold of various air carrier's aircraft. Three
major air carriers have been monitored and have shown similar
fluctuations in temperature and pressure (Lewis and Parolini,
1991). Lewis et al. (1990) noted decreases in VOC concentra-
tions in soil samples that were shipped compared to samples
that were analyzed in the field. If the container is of questionable
or unknown integrity, it should either be evaluated prior to use or
a previously characterized container should be used.
As discussed previously, samples that are immersed in metha-
nol have special shipping requirements. These samples must
be shipped as "Flammable Liquids" under Department of Trans-
portation (DOT) requirements. A secondary container is re-
quired for shipment of any item classified as a flammable liquid.
PRESERVATION
Improvements in operational factors such as sampling device
efficiency, sample transfer, containerizing, shipping, storage,
laboratory sample preparation, and analysis will reduce VOC
losses from soils. Two principal matrix-specific factors that can
contribute to the loss of VOC in soils are biodegradation and
volatilization. An effective preservation technique should act on
these matrix-specific factors to reduce losses of VOCs.
The required preservation technique for soil samples is storage
at 0° to 4°C in the dark. This technique retards biodegradation
airborne
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40
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10-5 0 5 10 15 20 25 30 * * 45
FEDERAL EXPRESS
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-5 0 5 10
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80
eo
40
20
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Elapsed Time (hr)
Figure 6. Temperature and pressure fluctuations recorded in
the cargo hold of various air carriers. Recording
device was shipped from Las Vegas, NV, to Peart
River, NY, and returned.
19
-------
processes mediated by soil microorganisms. Some microorgan-
isms, however, such as fungi, are biologically active even at
4°C. Wolf et al. (1989) investigated several methods (i.e.,
chemical and irradiation) for sterilizing soil and concluded that
mercuric chloride is one of the most effective preservatives that
causes minimal changes to the chemical and physical proper-
ties of the soil. Stuart et al.(1990) utilized mercuric chloride as an
antimicrobial preservative to stabilize ground-water samples
contaminated with gasoline. Other researchers (U.S. EPA
1991 a) have used mercuric chloride to retard biodegradation of
VOCs in soil samples. The soils were spiked with 150 ng/kg of
Target Compound List (TCL) VOCs and were preserved with 2.5
mg of mercuric chloride per 5 g of soil. The results indicated that
the amount of mercuric chloride needed to reduce biodegrada-
tion was directly related to the soil's organic carbon content. In
addition, the levels of mercuric chloride added to samples did
not interfere with sample handling or analysis. Currently, re-
search is underway to quantitate the required mercuric chloride
concentration as a function of soil organic content.
The loss of VOCs through volatilization is reduced by optimizing
sample handling procedures. When samples require laboratory
pretreatment, severe losses of VOCs (up to 100%) have been
observed. In order to minimize volatilization losses, several
preservatives have been examined (U.S. EPA 1991 a), including
solid adsorbents, anhydrous salts, and water/methanol extrac-
tion mixtures. The most efficient preservatives for reducing
volatilization of VOCs from soils have been two solid
adsorbents, Molecular Sieve - 5A™ (aluminum silicate desic-
cant) and Florasil™ (magnesium silicate desiccant). The addi-
tion of 0.2 mg per 5 g of soil greatly increased the recovery of
VOCs from spiked samples. The mechanism is believed to
involve the displacement of water from adsorption sites on the
soil particle and binding of VOCs to these freed sites. Currently,
research is in progress with soils obtained from actual contami-
nated sites.
LABORATORY PROCEDURES
Sample Storage
Most regulatory procedures specify storage of samples for VOA
at 4°C in the dark. Sample coolers should be opened under
chain-of-custody conditions, and the temperature inside the
cooler should be verified and noted. Samples should be trans-
ferred to controlled-temperature (4°C) refrigerators until analy-
sis. In many cases, insufficient cooling is provided during
transport. In these cases, data quality may be compromised.
Sample Preparation
The two most commonly used methods that satisfy regulatory
requirements forthe analysis of soil samples for VOCs are direct
purge and trap and methanol extraction. Each procedure has
benefits and limitations with respect to sample preparation prior
to VOC analysis of soils.
The modified purge-and-trap procedure has the following char-
acteristics:
• Homogenization of contents of wide-mouth jar will cause
significant VOC losses. The collection of a 5-g aliquot in the
field and placement into a tared vial sealed with a modified
purge-and-trap cap is recommended.
• Surrogate addition should be made to the soil in the field, if
possible.
• May be more susceptible to short-range spatial variability.
• Samples should be brought to ambient temperature before
purging.
• May be more suitable for low-level samples.
The methanol-immersion procedure has the following charac-
teristics:
• The key is to minimize the time samples are exposed to the
atmosphere prior to immersion into methanol.
• Minimum detection limits can be raised by a factor of 10 to 20.
• The best option for sample archival because VOCs are highly
soluble in methanol.
• Large-mass samples can be extracted in the field in a 1:1 ratio
and the methanol extract shipped to the laboratory for
analysis.
• Can collect composite samples.
The analytical methods that can be used for the analysis of soils
for VOCs are summarized in Table 12. An analytical method
should be selected that is compatible with the recommended
sample collection and containerizing procedure discussed ear-
lier.
CONCLUSIONS AND RECOMMENDATIONS
Current research on sampling soils for VOC analyses answers
many of the questions asked by RPMs and OSCs who conduct
site characterization and restoration.
1. There is no specific method or process that can be recom-
mended for sampling soils for VOA. A wide variety of
sampling devices are currently used for collecting soil
samples for VOA. Sampling device selection is site-specific,
and no single device can be recommended for use at ali
sites. Several different samplers, which cover a broad
range of sampling conditions and circumstances, are rec-
ommended for obtaining representative samples for VOC
analysis (Table 7). Procedures may vary for different VOCs.
Experiments have shown that a procedure that collects an
undisturbed, intact sample with a device that allows direct
transfer to a sample container (e.g., split-spoon, Shelby
tube, or zero-contamination sampler) is superior to a more
disruptive procedure that uses a crude bulk sampler (e.g.,
shovel, 'rowel, scoop, or spade) for maintaining the integrity
of VOCs in a soil sample. Large-diameter tube-type sam-
pling devices are recommended for collection of near-
surface samples. The same types of devices can be used
in conjunction with hollow-stem augers for collecting sub-
surface samples.
2. Transfer of the sample from the sampling device to the
container is a critical step in the process. Losses of as much
as 80% have been observed during this step. The faster the
soil can be removed from the sampling device and
20
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TABLE 12. METHODS FOR VOC ANALYSIS OF SOIL
Sample
Method Size
Extraction/analysis (g)
Sample
Preparation
Procedure
Sensitivity
(w/kg)
Data
Quality
Objective
Program
Comments
5030 / 8240
/8010
/ 8015
/8020
/8030
/ 8260
Purge and trap
5-10
Litigation
RCRA'
Sample transfer to
purge and trap is
critical.
5380 / 8240
/ 8010
/ 8015
/ 8020
/8030
/ 8260
5-100 Methanol extraction
500-1000
Litigation
RCRA
Sensitivity loss but
sample transfer
facilitated.
5031/8240
/ 8010
/ 8015
/ 8020
/ 8030
/ 8260
Field purge
5-10
Semi-
quantitative
RCRA
Sample can only be
analyzed once,
transfer and shipping
facilitated.
3810 / 8240
/ 8010
/ 8015
/8020
/ 8030
/ 8260
10
Heatto90°C
in water bath
and analyze
headspace
1000
Screening
forpurgeable
organics
RCRA
Can be performed
in the field.
3820
10
Hexadecane
extraction
followed by
GC/FID
500-1000
Screening
prior to GC
orGC/MS
analysis
RCRA
FID responses vary
with type of VOC.
624
Purge and trap
5-10
Litigation
CLP"
Similar to method
5030/B240 in
RCRA SW-846.
' U.S. EPA, 1986b
b U.S. EPA, 1982
21
-------
transferred into an airtight sample container, the smaller
the VOC loss. Liners make the removal and subsampling
of soil from the collection device more efficient.
3. The best method for transferring a sample from a large-
diameter coring device (or exposed test pit) into a sample
container is by collecting the appropriate size aliquot (for
laboratory analysis) with a small-diameter, hand-held corer
and extruding the subsample into a 40-mL VOA vial, then
sealing the vial with a modified purge-and-trap cap. Alter-
natively, contents of the large-diameter coring device can
be sectioned and immersed in methanol.
4. Small-diameter, hand-held corers can be used for col-
lecting samples from a freshly exposed face of a trench or
test pit, or for obtaining a subsample from a large-diameter
coring device. The use of a small-diameter, hand-held
corer is recommended for obtaining subsamples from
liner-held soil. Collection of a sample of the appropriate
size for a particular analytical procedure is optimal. The
required size of aliquot can be extruded into a 40-mL VOA
vial and sealed with a modified purgerand-trap cap. The
possibility exists of compositing several smali-diameter
core samples by immersing them in a single jar containing
methanol.
5. Sample containers vary in terms of air-tightness. Data are
available to indicate that there is a decrease in pressure
and an increase in temperature in the cargo holds of certain
air carriers. This is the worst possible set of conditions for
maintaining VOCs in containerized soil samples. Intact
seals on storage containers and adequate cooling is thus
critical for maintaining VOCs in soil samples. Shipping and
holding-time studies have shown that vials and jars may be
equally suited for containing VOCs in soil samples, the
laboratory pretreatment step needed to obtain an aliquot
from a jar-held sample causes significant losses of VOCs.
Commercially available shipping packages with built-in
cooling materials (e.g., Freeze Gel Packs® or Blue Ice®)
are available. Whenever possible, an integrated sampling
approach should be employed to obtain the most represen-
tative samples possible. Soil-gas surveying coupled with
on-site soil sampling and analyses followed by the Re-
source Conservation and Recovery Act (RCRA) or CLP
laboratory analyses may provide valuable information on
the partitioning of VOCs at a site.
6. The current preservation technique for soil samples is
storage at 4°C in the dark. Biological activity may continue
at this temperature. The addition of mercuric chloride to the
soil may reduce biodegradation of VOCs. The amount of
mercuric chloride to be added, however, is a function of the
organic carbon content in the soil. The most promising
preservatives for reducing losses of VOCs through volatil-
ization are solid adsorbents such as Molecular Sieve - 5A™
and Florasil™.
22
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Effect of soil moisture on the sorption of trichloroethene vapor to
vadose-zone soil at Picatinny Arsenal, New Jersey. Env. Sci.
Tech. 24:676-683.
Spencer, W. F. and M. M. Cliath. 1970. Soil Sci. Soc. Am. Proc.
34:574-579.
Spencer, W. F., M. M. Cliath, W. A. Jury, and L-Z. Zhang. 1988.
Volatilization of organic chemicals from soil as related to their
Henry's Law constants. J. Env. Qual. 17(3):504-509.
Stuart, J. D„ V. D. Roe, W. M. Nash, and G. A. Robbins. 1990.
Manual headspace method to analyze for gasoline contamina-
tion of ground water by capillary column gas chromatography.
Personal Communication.
U.S. EPA. 1986b. Test Methods for Evaluating Solid Waste
(SW-846), Method 8240, Off. Solid Waste and Emergency
Response (3rd Edition).
U.S. EPA. 1987. Data Quality Objectives for Remedial Re-
sponse Activities: Development Process. EPA/540/G-87/003,
Off. Solid Waste and Emergency Response, Washington, D.c!
U.S. EPA. 1988. Field Screening Method Catalog User's Guide.
EPA/540/2-88/005, Sept. 1988, Office of Emergency and Re-
medial Response, Washington, D.C.
U.S. EPA. 1991a. Investigation of Sample and Sample Handling
Techniques for the Measurement of Volatile Organic Com-
pounds in Soil. University of Nevada, Las Vegas, submitted to
U.S. EPA, Environmental Monitoring Systems Laboratory, Las
Vegas, NV (in preparation).
U.S. EPA. 1991b. Manual for Sampling Soils for Volatile Organic
Compounds. Environmental Monitoring Systems Laboratory,
Las Vegas, NV, 26 pp. (in preparation).
van Ee, J. J., L. J. Blume, and T. H. Starks. 1990. A Rationale
for the Assessment of Errors in the Sampling of Soils, EPA/600/
4-90/013, Office of Research and Development, Environmental
Monitoring Systems Laboratory, Las Vegas, NV, 57 pp.
Verschueren, K. 1983. Handbook of Environmental Data on
Organic Chemicals, Van Nostrand Reinhold Company, New
York, NV (2nd Edition).
Vogel, T. M. and P. L. McCarty. 1985. Biotransformation of
tetrachloroethylene to trichloroethylene, dichloroethylene, vinyl
chloride, and carbon dioxide under methanogenic conditions.
Appl. Environ. Microbiol. 49:1080-1084.
Voice, T. C. and W. J. Weber, Jr. 1983. Sorption of hydrophobic
compounds by sediments, soils, and suspended solids - I.
Theory and background. Wat. Res. 17(10):1433-1441.
Wolf, D. C., T. H. Dao, H. D. Scott, and T. L Lavy. 1989.
Influence of sterilization methods on selected soil microbiologi-
cal, physical, and chemical properties. J. Env. Qual. 18:39-44.
U.S. EPA. 1982. Test Method 624 (Purgeabtes). Methods for
Organic Chemical Analysis of Municipal and Industrial Wastes,
EPA-600/4-82-057, U.S. EPA Environmental Support Labora-
tory, Cincinnati, OH.
24
GOVERNMENT HUNTING OfflCE; MM • SM-MT/1MB
-------
United States
Environmental Protection
Agency
Office of
Research and
Development
Office of Solid
Waste
and Emergency
Response
EPA.5404-91 003
March 1991
&ERA Ground-Water Issue
CHARACTERIZING SOILS FOR
HAZARDOUS WASTE SITE ASSESSMENTS
R. P. Brackanridge', J. R. Williams1, and J. F. Kack'
INTRODUCTION
The Regional Superfund Ground Water
Forum it a group of ground-water scientist*
representing EPA's Regional Offices, orga-
nized to exchange up-to-date information re-
lated to ground-water remediation at hazard-
ous wasta site*. Soil characterization at
hazardous wasta sites la an iaaua identified by
tha forum as a oonoarn of CERCLA dedaion-
makers.
To address this issue, this paper was pre-
pared through support from EMSL-LV and
RSKERL, under the direction of R. P.
Breckenridge, with the support of the
Superfund Technical Support Project. For
further information oontact Ken Brown, EMSL-
LV Center Director, at FTS 545-2270 or R. P.
Breckenridge at FTS 583-0757.
Site investigation and remediation under the
Superfund program is performed using the
CERCLA remedial investigation/feasibility
study (RI/FS) process. The goal of the RI/FS
process is to reach a Record of Decision
(ROO) in a timely manner. Soil characteriza-
tion provides data types required for decision
making in three distinct RI/FS tasks:
1. Determination of the nature and extent of
soil contamination.
2. Risk assessment, and determination of
risk-based soil clean-up levels.
3. Determination of the potential effective-
ness of soil remediation alternatives.
Identification of data types required for the first
taak, determination of the nature and extent of
contamination, is relatively straightforward.
The nature of contamination is related to the
typee of operations conducted at the site.
Existing records, if available, and interviews
with personnel familiar with the site history are
good sources of information to help determine
the types of contaminants potentially present
This information may be used to shorten the
list of target anaiytes from the several hundred
contaminants of concern in the 40 CFR Part
264 list (Date 7-1-89). Numerous guidance
documents are available for planning all
' IdshoNiSoMiEnginasiingLAQmlwy.EmiranmanislSaisnossndTsdimtogyQioup. Idaho Fah. 063411
* Soli Stistiai. U.S. EPA/B. S. Ksw Emrtrownortal Haiti! HwtMoiy, Ada. OK 74820
\T~ J
Superfund Technology Support Center lor Monitoring
and Sits Characterization, Environmental Monitoring
Systems Laboratory Las Vegas, NV
Superfund Technology Support Center for
Ground-Water Fat* and Transport, Robert S. Kerr
Environmental Research Laboratory Ada, OK
U& EM, WnNnglM, Q.C.
WMtarW.K0wfck.Jr.. Phi). Director
Printed on Recycled Paper
-------
aspects of the subsequent sampling effort (US EPA. 1987a.
1988a, 1988b, and Jenkins et al., 1988).
The extent of contamination is also related to the types of
operations conducted at the site. Existing records, if available,
and interviews with personnel familiar with the site history are
also good sources of information to help determine the extent of
contamination potentially present. The extent of contamination
is dependent on the nature of the contaminant source(s) and the
extent of contaminant migration from the source(s). Migration
routes may include air, via volatilization and fugitive dust emis-
sions; overland flow; direct discharge; leachate migration to
ground water and surface runoff and erosion. Preparation of a
preliminary site conceptual model is therefore an important step
in planning and directing the sampling effort The conceptual
model should identify the most likely locations of contaminants
in soil and the pathways through which they move.
The data type requirements for tasks 2 and 3 are frequently leu
well understood. Tasks 2 and 3 require knowledge of both the
nature and extent of contamination, the environmehtal fate and
transport of the contaminants, and an appreciation of the need
for quality data to select a viable remedial treatment technique.
Contaminant fate and transport estimation is usually performed
by computer modeling. Site-specific information about the soils
in which contamination occurs, migrates, and interacts with, is
required as input to a model. The aocuracy of the model output
is no better than the accuracy of the input information.
The purpose of this paper is to provide guidance to Remedial
Project Managers (RPM) and On-Scene Coordinators (OSC)
concerning soil characterization data types required for
decision-making in the CERCLA RI/FS process related to risk
assessment and remedial alternative evaluation for contami-
nated soils. Many of the problems that arise are due to a lack of
understanding the data types required for tasks 2 and 3 above.
This papar describes the soil characterization data types re-
quired to conduct modal based risk assessment for task 2 and
the selection of remedial design for task 3. The Information
presented in this paper is a compilation of current information
from the literature and from experience combined to meet the
purpose of this paper.
EMSL-Las Vegas and RSKERL-Ada convened a technical
committee of experts to examine the issue and provide technical
guidance based on current scientific information. Members of
the committee were Joe R. Williams, RSKERL-Ada; Robert Q.
Baca. Robert P. Breckenridge, Alan B. Crockett, and John F.
Keck from the Idaho National Engineering Laboratory, Idaho
Falls. ID; Gretchen L Rupp, PE, University of Nevada-Las
Vegas; and Kan Brown; EMSL-LV.
This document was compiled by the authors and edited by the
members of the committee and a group of peer reviewers.
Characterization of a hazardous waste site should be done
using an integrated investigative approach to determine quickly
and cost effectively the potential health effects and appropriate
response measures at a site. An integrated approach involves
consideration of the different types and sources of contami-
nants, their fate as they are transported through and are parti-
tioned, and their impact on different parts of the environment.
CONCERNS
This paper addresses two concerns related to soil characterize
tion for CERCLA remedial response. The first concern is th«
applicability of traditional soil classification methods to CERCLa
soil characterization. The second is the identification of soil
characterization data types required for CERCLA risk asses*
merit and analysis of remedial alternatives. These concerns ar»
related, in that the Data Quality Objective (000) process
addresses both. The DQO process was developed, in part, to
assist CERCLA decision-makers in identifying the data type*
data quality, and data quantity required to support decisions that
must be made during the RI/FS process. Data Quality Obier-.
tfves for Remedial Response Activities: Development Procex*
(US EPA, 1987b) is a guidebook on developing DQOs. Thj.
process as it relates to CERCLA soil characterization is di%.
cussed in the Data Quality Objective section of this paper.
Data types required for soil characterization must be determined
earty in the RI/FS process, using the DQO process. Often, th«
first soil data types related to risk assessment and remedial
alternative selection available during a CERCLA site investiga-
tion are soil textural descriptions from the borehole logs pr%-
pared by a geologist during investigations of the nature and
extent of contamination. These boreholes might include instal-
lation of ground-water monitoring wells, or soil boreholes. Typi-
cally. borehole logs contain soil lithology and textural descrip.
tons, based on visual analysis of drill cuttings.
Preliminary site data are potentially valuable, and can provide
modelers and engineers with data to begin preparation of the
conceptual modal and perform scoping calculations. Soil tex-
ture affects movement of air and water in soil, infiltration rata,
porosity, water holding capacity, and other parameters.
Changes in lithology identify heterogeneities in the subsurface
(i.e., low permeability layers, etc.). Soil textural classification is
therefore important to contaminant fate and transport modeling,
and to screening and analysis of remedial alternatives. How-
ever, unless collected properly, soil textural descriptions are of
limited value tor the following reasons:
1. There are several different systems for classification of soil
panicles with respect to size. To address this problem it is
important to identify which system has been or will be used
to classify a soil so that data can be property compared.
Figure 1 can be used to compare the different systems (Gee
and Bauder, 1986). Keys to Soil Taxonomy (Soil Survey
Staff, 1990) provides details to one of the more useful
systems that should be consulted prior to classifying a site's
soils.
2. The accuracy of the field classification is dependent on the
skill of tha obeerver. To overcome this concern RPMs and
OSCs should collect soil textural data that are quantitative
rather than qualitative. Soil texture can be determined from
a soil sample by sieve analysis or hydrometer. These data
types are superior to qualitative description based on visual
analysis and are mora likely to meet DQOs.
3. Evan if the field person accurately classifies a soil (e.g., as
a silty sand or a sandy loam), textural descriptions do not
afford accurate estimations of actual physical properties
required for modeling and remedial alternative evaluation,
2
-------
such as hydraulic conductivity. For example, the hydraulic
conductivity of silty-sand can range from 105 to 101 cm/sec
(four orders of magnitude).
These ranges of values may be used for bounding calculations,
or to assist in preparation of the preliminary conceptual model.
These data may therefore meet DQOs for initial screening of
remedial alternatives, for example, but will likely not meet DQOs
for detailed analysis of alternatives.
DATA QUALITY OBJECTIVES
EPA has developed the Data Quality Objective (DQO) process
to guide CERCLA site characterization. The relationship be-
tween CERCLA RI/FS activities and the DQO process is shown
in Figure 2 (US EPA, 1988c, 1987a). The DQO process occurs
in three stages:
• Stage 1. Identify Decision Types. In this stage the types of
decisions that must be made during the RI/FS are identified.
PARTICLE SIZE UMTT CLASSIFICATION
USOA CSSC ISSS ASTM (unlfM)
0.001
-- 20
-- 10
-- 4
1/2 la
3/4 In.
3 In.
CLAY

COARSE
CLAY
COARSE
CLAY
SILT
FINE
SILT
SILT
FINES
(SILT AND
CLAY)
MEDIUM
SILT
COARSE
SILT
FINE
SAND
VERY PINK
SAND
VERY PINE
SAND
FINE
SAND
FINS
SAND
FINE
SAND
MEDIUM
SAND
MEDIUM
SAND
COARSE
SAND
COARSE
SAND
COARSE
SAND
MEDIUM
SAND
VERY COARSE
SAM)
VERY COARSE
SAND
FINE
GRAVEL
GRAVEL
GRAVEL
COARSE
SAND
PINE
GRAVEL
COARSE
GRAVEL
COARSE
GRAVEL
COMLES
COMLES

COMLES
USDA-US. DEPARTMENT OF AGRICULTURE, (SOIL SURVEY STAFF, 1975)
CCS - CANADA SOIL SURVEY COMMITTEE (McKEAGUE, 1978)
ISSS - INTERNATIONAL SOIL SCI. SOC. (YONG ANO WARKENT1N, 1968)
ASTM - AMERICAN SOCIETY FOR TESTING t MATERIALS (ASTM, D-2487,1965a)
Figure 1. Particle-size limits according to several current
classification schemes (Gee and Bauder, 1986).
The types of decisions vary throughout the RI/FS process, but
in general they become increasingly quantitative as the pro-
cess proceeds. During this stage it is important to identify and
involve the data users (e.g. modelers, engineers, and scien-
tists), evaluate available data, develop a conceptual site
model, and specify objectives and decisions.
Stage 2. Identify Data Uses/Needs. In this stage data uses
are defined. This includes identification of the required data
types, data quality and data quantity required to make deci-
sions on how to:
- Perform risk assessment
- Perform contaminant fate and transport modeling
- Identify and screen remedial alternatives
* Stage 3. Design Data Collection Program. After Stage 1 and
2 activities have been defined and reviewed, a data collection
program addressing the data types, data quantity (number of
samples) and data quality required to make these decisions
needs to be developed as part of a sampling and analysis
plan.
Although this paper focuses on data types required for decision-
making in the CERCLA RI/FS process related to soil contami-
nation, references are provided to address data quantity quality
issues.
Data Typos
The OSC or RPM must determine which soil parameters are
needed to make various RI/FS decisions. The types of deci-
sions to be made therefore drive selection of data types. Data
types required for RI/FS activities including risk assessment,
contaminant fate and transport modeling and remedial alter-
native selection are discussed in Soil characteristics Data Types
Required for Modeling Section, and the Soil Characterization
Data Type Required for Remedial Alternative Selection Section.
Data Quality
The RPM or OSC must decide "How good does the data need
to be in order for me to make a given decision?". EPA has
assigned quality levels to different RI/FS activities as a guide-
line. Data Quality Objectives for Remedial Response Activities
(US EPA, 1987a) offers guidance on this subject and contains
many useful references.
Data Quantity
The RPM or OSC must decide "How many samples do I need to
determine the mean and standard deviation of a given param-
eter at a given rite?", or "How does a given parameter vary
spatially across the site?". Decisions of this type must be
addressed by statistical design of the sampling effort. The Soil
Sampling Quality Assurance Guide (Barth et al., 1989) and Data
Quality Objectives for Remedial Response (US EPA. 1987a)
offer guidance on this subject and contain many useful refer-
ences.
3
-------
Remedial
Investigation
Report
Record
of Decision
Feasibility
Study
Report
Rl
PHASE 1

PHASE!
Rl

PHASED
FS
PHASE II
Figure 2. Phased RI/FS approach and the DQO process (EPA, 1987a).
4
-------
IMPORTANT SOIL CHARACTERISTICS IN SITE
EVALUATION
Tables 1 and 2 identify methods for collecting and determining
data types for soil characteristics either in the field, laboratory,
or by calculation. Soil characteristics in Table 1 are considered
the primary indicators that are needed to complete Phase I of the
RI/FS process. This is a short, but concise list of soil data types
that are needed to make CERCLA decisions and should be
planned for and collected early in the sampling effort. These
primary data types should allow for the initial screening of
remedial treatment alternatives and preliminary modeling of the
site for risk assessment. Many of these characteristics can be
obtained relatively inexpensively during periods of early field
work when the necessary drilling and sampling equipment are
already on site. Investigators should plan to collect data for all
the soil characteristics at the same locations and times soil
boring is done to install monitoring wells. Geophysical logging of
the well should also be considered as a cost effective method for
collecting lithologic information prior to casing the well. Data
quality and quantity must also be considered before beginning
collection of the appropriate data types.
The soil characteristics in Table 2 are considered ancillary only
because they are needed in the later stages and tasks of the
OQO process and the RI/FS process. If the site budget allows,
collection of these data types during early periods of field work
will improve the database available to make decisions on
remedial treatment selection and model-based risk assess-
ments. Advanced planning and knowledge of the need for the
ancillary soil characteristics should be factored into early site
work to reduce overall costs and the time required to reach a
ROD. A small additional investment to collect ancillary data
during early site visits is almost always more cost effective than
having to send crews back to the field to conduct additional soil
sampling.
Further detailed descriptions of the soil characteristics in Tables
1 and 2 can be found in Fundamentals of Soil Physics and Ap-
plications of Soil Physics (Hillel, 1980) and in a series of articles
by Dragun (1988, 1988a, 1988b). These references provide
excellent discussions of these characteristics and their influ-
ence on water movement in soils as well as contaminant fate and
transport.
SOIL CHARACTERISTICS DATA TYPES REQUIRED
FOR MODELING
The information presented here is not intended as a review of all
data types required for all models, instead it presents a sampling
of the more appropriate models used in risk assessment and
remedial design.
in the vadose zone, and of transformation and degradation
processes.
• Effectiveness assessment of remedial alternatives This
task may also require determination of the rates and extents
of contaminant movement in the vadose zone, and of rates
and extents of transformation and degradation processes.
Technology-specific data requirements are cited in the Soil
Characterization Data Type Required for Remedial Alterna-
tive Selection Section.
The types, quantities, and quality of site characterization data
required for modeling should be carefully considered during Rl/
FS scoping. Several currently available vadose zone fate and
transport models are listed in Table 3. Soil characterization data
types required for each model are included in the table. Model
documentation should be consulted for specific questions con-
cerning uses and applications.
The Superfund Exposure Assessment Manual discusses vari-
ous vadose zone models (US EPA, 1988e). This document
should be consulted to select codes that are EPA-approved.
Data Types Required for Modeling
Soil characterization data types required for modeling are in-
cluded in Tables 1 and 2. Most of the models are one- or
two-dimensional solutions to the advection-dispersion equa-
tion, applied to unsaturated flow. Each is different in the extent
to which transformation and degradation processes may be
simulated; various contaminant release scenarios are accom-
modated; heterogeneous soils and other site-specific charac-
teristics are accounted for. Each, therefore, has different data
type input requirements.
All models require physicochemical data for the contaminants of
concern. These data are available in the literature, and from
EPA databases (US EPA, 1988c,d). The amount of physico-
chemical data required is generally related to the complexity of
the model. The models that account for biodegradation of
organics, vapor phase diffusion and other processes require
more input data than the relatively simpler transport models.
Data Quality and Quantity Required for Modeling
DQOs for the modeling task should be defined during RI/FS
scoping. The output of any computer model is only as valid as
the quality of the input data and code itself. Variance may result
from the data collection methodology or analytical process, or as
a result of spatial variability in the soil characteristic being
measured.
Uses of Vadose Zone Models for Cerela Remedial
Response Activities
Models are used in the CERCLA RI/FS process to estimate
contaminant fate and transport. These estimates of contami-
nant behavior in the environment are subsequently used for:
• Risk assessment. Risk assessment includes contaminant
release assessment, exposure assessment, and determining
risk-based clean-up levels. Each of these activities requires
estimation of the rates and extents of contaminant movement
In general, the physical and chemical properties of soils vary
spatially. This variation rarely follows well defined trends; rather
it exhibits a stochastic (i.e., random) character. However, the
stochastic character of many soil properties tends to follow
classic statistical distributions. For example, properties such as
bulk density and effective porosity of soils tend to be normally
distributed (Campbell, 1965). Saturated hydraulic conductivity,
in contrast, is often found to follow a log-normal distribution.
Characterization of a site, therefore, should be performed in
such a manner as to permit the determination of the statistical
characteristics (i.e., mean and variance) and their spatial
correlations.
(Continued on page 8)
5
-------
TABLE 1. MEASUREMENT METHODS FOR PRIMARY SOIL CHARACTERISTICS
NEEDED TO SUPPORT CERCLA DECISION-MAKING PROCESS
Measurement Technique/Method (w/Reference)
Soil Characteristic* FieW Laboratory Calculation or Lookup Mathod
Bulk density
Soil pH
Texture
Depth to
groundwater
Horizons or
stratigraphy
Hydraulic
conductivity
(saturated)
Water retention
(soil water
characteristic
curves)
Air permeability
and water content
Porosity (pore
volume)
Climate
Neutron probe (ASTM, 1985),
Gamma radiation (Blake and Hartage,
1986, Blake. 1965).
Measured in field in same manner as
in laboratory.
Collect composite sample for each soil
type. No field methods are available,
except through considerable
experience of "feeling" the soil for an
estimation of % sand, silt, and ciay.
Ground-water monitoring wells or
piezometers using EPA approved
methods (EPA 1985a).
Soil pits dug with backhoa are best. If
safety and cost are a concern, soil
bores can be collected with either a
thin wall sample driver and veilmayer
tube (Brown et al., 1990).
Auger-hole and piezometer methods
(Amoozeger and Warrick, 1986) and
Gueiph permeameter (Reynolds &
Elrick. 1985; Reynolds & Elrick. 1986).
Field methods require a considerable
amount of time, effort, and equipment
Coring or excavation for lab analysis
(Blake and Hartage, 1986).
Using a glass electrode in an aqueous
slurry (ref. EPRIEN-6637) Analytical
Method - Method 9045, SW-846, EPA.
ASTM D 522-63 Method for Particle
Analysis of Soils. Sieve analysis better at
hazardous waste sites because organics
can effect hydrometer analysis
(Kluate, 1986).
Not applicable.
Not applicable.
Constant head and falling head methods
(Amoozeger and Warrick, 1986).
Obtained through wetting or drainage of
core samples through a series of known
For a good discussion of these methods pressure heads from tow to high or high
refer to Bruce and Luxmoore (1986). to low, respectively (Klute, 1986).
None
Several methods have been used,
however, all use disturbed soil samples.
For field applications the structure of
soils are very important, For more
information refer to Corey (1986).
Gas pyenometer (Danielson and
Sutherland, 1986).
Precipitation measured using either
Sacramento gauge for accumulated value
or weighing gauge or tipping bucket gauge
for continuous measurement (Finkelstein
et al., 1963; Kile, 1979). Soil temperature
measured using thermocouple.
Not applicable.
Not applicable.
Not applicable.
Not applicable.
Not applicable.
May be possible to obtain information
from SCS soil survey for the site.
Although there are tables available that
list the values for the saturated
hydraulic conductivity, it should be
understood that the values are given for
specific soil textures that may not be the
same as those on the site.
Some look-up and estimation methods
are available, however, due to high
spatial variabiltiy in this characteristic
they are not generally recommended
unless their use is justified.
Estimation methods for air permeability
exist that cioseiy resemble the estimation
methods for unsaturated hydraulic
conductivity. Example models those
developed by Brooks and Corey (1964)
and van Genuchten (1980).
Calculated from particle and bulk
densities (Danielson and Sutherland,
Data are provided in the Climatic Atlas of
the United States or are available from
the National Climatic Data Center,
Ashevile, NC Telephone (704) 259-0682.
SoU chsraderiste art dtamed in general except where specific cases relate to dHferant watte type* (i.e„ metals, hydrophobic organics or polar organics).
6
-------
TABLE 2. MEASUREMENT METHODS FOR ANCILLARY SOIL PARAMETERS
NEEDED TO SUPPORT CERCLA DECISION-MAKING PROCESS
Measurement Technique/Method (w/Reference)
Soil Characteristic' Field
Laboratory
Calculation or Lookup Method
Organic carbon Not applicable.
Capacity Exchange See Rhoades for field methods.
Capacity (CEC)
Erodibility
Water erosion
Universal Soil Loss
Equation (USLE)
or Revised USLE
(RUSLE)
Wind erosion
Vegetative cover
Soil structure
Organic carbon
partition
cooefficient (KJ
Redox couple ratios
of waste/soil system
High temperature combustion (either
wet or dry) and oxidation techniques
(Powell et al., 1989) (Powell, 1990).
(Rhoades, 1982).
Not applicable.
Measurement/survey of slope (in ft
rise/ft run or %), length of field,
vegetative cover.
Air monitoring for mass of containment.
Field length along prevailing wind
direction.
Visual observation and documented
using map. USDA can aid in identification
of unknown vegetation.
Classified into 10 standard kinds - see
local SCS office for assistance (Soil
Survey Staff, 1990) or Taylor and
Ashcroft (1972), p. 310.
In situ tracer tests (Freeze aid Cherry,
1979).
Platium electrode used on lysimeter
sample (ASTM, 1987).
Not applicable.
Not applicable.
Not applicable.
Not applicable.
(ASTM E 1195-87,1988)
Same as field.
Estimated using standard equations and
graphs (Israelsen et al.. 1980) field data
for slope, field length, and cover type
required as input. Soils data can be
obtained from the local Soil Conservation
Service (SCS) office.
A modified universal soil loss equation
(USLE) (Williams, 1975) presented in
Mills et al.. (1982) and US EPA (1988d)
source for equations.
The SCS wind loss equation (Israelsen
et al., 1980) must be adjusted (reduced)
to account for suspended particles of
diameter slO^m Cowherd et al., (1985)
for a rapid evaluation (£24 hr) of particle
emission fro a Superfund site.
See local soil survey for the site.
Calculated from K , water solubility
(Mills et al., 1985; Sims et al., 1986).
Can be calculated from concentrations of
redox pairs or 02 (Stumm and Morgan, 1981).
Liner soil/water In situ tracer tests (Freeze and Cherry,
partition coefficient 1979)
Batch experiment (Ash et al., 1973);
column tests (van Genuchten and
Wierenga, 1986).
Soil oxygen 02 by membrane electrode Ot diffusion Same as field,
content (aeration) rate by Pt microelectrode (Phene, 1986).
Os by field GC (Smith, 1983).
Mills etai., 1965.
Calculated from pE (Stumm and Morgan,
1981) or from O, and soil-gas diffusion
rate.
(Continued)
7
-------
TABLE 2. (CONTINUED)
Measurement Technique/Method (w/Reference)
Soil Characteristic' Field
Laboratory
Calculation or Lookup Method
Soil temperature (as Thermotery (Taylor and Jackson, 1986).
it affects volatilization)
Clay mineralogy Parent material analysis.
Unsaturated
hydraulic
conductivity
Moisture content
Same as field.
Soil biota
Brown and Associates (1960).
Unsteady dranage-flux (or instantaneous
profile) method and simplified unsteady
drainage flux method (Green et al.,
1986).The instantaneous profile method
was initially developed as a laboratory
method (Watson, 1966), however it was
adapted to the field (HiM et al., 1972).
Constant-head borehole inflitration
(Amoozegar and Warrick, 1986).
Two types of techniques - indirect and
direct. Direct menthods, (i.e., gravimetric
sampling), considered the most accurate,
with no calforation required. However,
methods are destructive to field systems.
Methods involve collecting samples,
weighing, drying and re-weighing to
determine field moisture. Indirect methods
rely on calibration (Klute, 1986).
No standard method exists (see model or
remedial technology for input or remedial
evaluation procedures).
X-ray diffraction (Whittig and Allardice, 1986).
Not usually done; results very difficult to
obtain.
A number of estimation methods exists,
each with their own set of assumptions
and requiremnts. Reviews have been
presented by Mualem (1986), and
van Gehuchten (in press).
No standard method exists; can use agar
plate count using MOSA method 99-3
p. 1462 (Klute, 1986).
' Soil characteristics are discussed in general except where specific cases relate to different waste types (i.e., metal*, hydrophobic organic* or polar organic*).
Significant advances have been made in understanding and
describing the spatial variability of soil properties (Neilsen and
Bouma, 1985). Geostatistical methods and techniques (Clark,
1982; Davis, 1986) are available for statistically characterizing
soil properties important to contaminant migration. Information
gained from a geostatistical analysis of data can be used for
three major purposes:
• Determining the heterogeneity and complexity of the site;
• Guiding the data collection and interpretation effort and thus
identifying areas where additional sampling may be needed
(to reduce uncertainty by estimating error); and
• Providing data for a stochastic model of fluid flow and con-
taminant migration.
One of the geostatistical tools useful to help in the interpolation
or mapping of a site is referred to as kriging (Davis, 1986).
General kriging computer codes are presently available. Ap-
plication of this type of tool, however, requires an adequate
sample size. As a rule of thumb, 50 or more data points are
needed to construct the semivariogram required for use in
kriging. The benefit of using kriging in site characterization is
that it allows one to take point measurements and estimate soil
characteristics at any point within the domain of interest, such as
grid points, for a computer model. Geostatistical packages are
available from the US EPA, Geo-EAS and GEOPACK (Englund
and Sparks, 1988 and Yates and Yates, 1990).
The use of stochastic models in hydrogeology has increased
significantly in recent years. Two stochastic approaches that
have been widely used are the first order uncertainty method
(Dettinger and Wilson, 1981) and Monte Carlo methods (Clifton
et al., 1985; Sagar et al., 1986; Eslinger and Sagar, 1988).
Andersson and Shapiro (1983) have compared these two ap-
proaches for the case of steady-state unsaturated flow. The
Monte Carlo methods are more general and easier to implement
than the first order uncertainty methods. However, the Monte
Carlo method is more computationally intensive, particularly for
multidimensional problems.
(Continued on page 10)
8
-------
TABLE 3. SOIL CHARACTERISTICS REQUIRED FOR VADOSE ZONE MODELS
Model Name
[Reference^)]
Properties and Parameters
Help
(A,B)
Sesoil
(C,D)
Creams
(E,F)
PRZM
(G,H,I)
Vadoft
(H,j)
Minteq
(J)
Fowl™
(K)
Ritz
(L)
Vip
(M)
Chemflo
(N)
Soil bulk density
o
•
•
•
•
0
•
•
•
•
Soil pH
o
•
o
o
o
•
•
o
o
o
Soil texture
•
o
•
•
•
o
o
•
•
o
Depth to ground water
o
•
o
o
•
o
o
o
o
o
Honzons (soil layering)
•
•
•
•
•
o
o
o
o
o
Saturated hydraulic conductivity
•
•
•
•
•
o
•
•
•
•
Water retention
•
•
•
•
•
o
•
o
o
•
Air permeability
o
•
o
o
o
o
o
o
•
o
Climate (precipitation)
•
•
•
•
o
o
•
•
•
•
Soil porosity
•
•
•
•
•
o
o
•
•
o
Soil organic content
o
•
•
•
•
•
o
•
•
o
Cation Exchange Capacity (CEC)
o
•
o
o
o
•
o
o
o
o
Degradation parameters
•
•
•
•
•
o
o
•
•
•
Soil grain size distribution
o
o
o
o
0
o
o
o
o
o
Soil redox potential
o
o
o
o
0
•
o
o
o
o
Soil/water partition coefficients
o
•
•
•
•
•
•
•
•
•
Soil oxygen content
o
o
o
o
o
o
o
o
•
o
Soil temperature
o
•
o
•
•
•
o
•
•
o
Soil mineralogy
o
•
o
o
o
o
o
o
o
o
Unsaturated hydraulic conductivity
•
•
•
•
•
o
•
o
o
•
Saturated soil moisture content
•
•
•
•
•
o
•
•
•
•
Microorganism population
o
o
o
o
o
o
o
o
o
o
Soil respiration
o
o
o
0
o
o
o
o
o
o
Evaporation
•
•
•
•
o
o
o
•
•
•
Air/water contaminant densities
o
o
o
o
o
o
•
•
•
o
Air/water contaminant viscosities
o
o
o
o
o
o
o
o
o
o
A. Schroeder, etal., 1984. F. Devaurs and Sponger, 1988. K. Hostetter, Enckson, and Rai, 1988 ® Required O Not required OUsedindire y
B. Schroeder, et al., 1984a. G. Carsel etal., 1984. L Notager and Willaims, 1988 • used in ther estimation ol other required
C. Bonazountas and Wagner, 1984. H. Dean et al., 1989. M. Stevens et al.,1989 characteristics or the intrpretation ot the models,
D. Chen. Wollman, and Liu. 1987. I. Dean etal., 1989a N. Notager etal., 1989. but not directly entered as input to models.
E. Leonard and Ferreira, 1984. J, Brown and Allison, 1987.
9
-------
Application of stochastic models to hazardous waste sites has
two main advantages. First, this approach provides a rigorous
way to assess the uncertainty associated with the spatial vari-
ability of soil properties. Second, the approach produces model
predictions in terms of the likelihood of outcomes, i.e., probabil-
ity of exceeding water quality standards. The use of models at
hazardous waste sites leads to a thoughtful and objective
treatment of compliance issues and concerns.
In order to obtain accurate results with models, quality data
types must be used. The issue of quality and confidence in data
can be partially addressed by obtaining as representative data
as possible. Good quality assurance and quality control plans
must be in place for not only the acquisition of samples, but also
for the application of the models (van der Heijde, et al., 1989).
Specific soil characteristics vary both laterally and vertically in
an undisturbed soil profile. Different soil characteristics have
different variances. As an example, the sample size required to
have 95 percent probability of detecting a change of 20 percent
in the mean bulk density at a specific site was 6; however, for
saturated hydraulic conductivity the sample size would need to
be 502 (Jury, 1986). A good understanding of site soil charac-
teristics can help the investigators understand these variations.
This is especially true for most hazardous waste sites because
the soils have often been disturbed, which may cause even
greater variability.
An important aspect of site characterization data and models is
that the modeling process is dynamic, i.e., as an increasing
number of "simplifying" assumptions are needed, the complexity
of the models must increase to adequately simulate the addi-
tional processes that must be included. Such simplifying as-
sumptions might include an isotropic homogeneous medium or
the presence of only one mobile phase (Weaver, et al., 1989).
In order to decrease the number of assumptions required, there
is usually a need to increase the number of site-specific soil
characteristic data types in a model (see Table 2); thus providing
greater confidence in the values produced. For complex sites,
an iterative process of initial data collection and evaluation
leading to more data collection and evaluation until an accept-
able level of confidence in the evaluation can be reached can be
used.
Table 3 identifies selected unsaturated zone models and their
soil characteristic needs. For specific questions regarding use
and application of the model, the reader should refer to the
associated manuals. Some of these models are also reviewed
by Donigan and Rao (1986) and van der Heijde et al. (1988).
SOIL CHARACTERISTICS OATA TYPES REQUIRED
FOR REMEDIAL ALTERNATIVE SELECTION
Remedial Alternative Selection Procedure
The CERCLA process involves the identification, screening and
analysis of remedial alternatives at uncontrolled hazardous
waste sites (US EPA, 1988c). During screening and analysis,
decision values for process-limiting characteristics for a given
remedial alternative are compared to site-specific values of
those characteristics. If site-specific values are outside the
range required for effective use of a particular alternative, that
alternative is less likely to be selected. Site soil conditions are
critical process-limiting characteristics.
10
Process-Limiting Characteristics
Process-limiting characteristics are site- and waste-specific
data types that are critical to the effectiveness and ability to
implement remedial processes. Often, process-limiting charac-
teristics are descriptors of rate-limiting steps in the overall
remedial process. In some cases, limitations imposed by
process-limiting characteristics can be overcome by adjustment
of soil characteristics such as pH, soil moisture content, tem-
perature and others. In other cases, the level of effort required
to overcome these limitations will preclude use of a remedial
process.
Decision values for process limiting characteristics are increas-
ingly available in the literature, and may be calculated for
processes where design equations are known. Process limiting
characteristics are identified and decision values are given for
several vadose zone remedial alternatives in Table 4. For
waste/site characterization, process-limiting characteristics
may be broadly grouped in four categories:
1. Mass transport characteristics
2. Soil reaction characteristics
3. Contaminant properties
4. Engineering characteristics
Thorough soil characterization is required to determine site-
specific values for process-limiting characteristics. Most reme-
dial alternatives will have process-limiting characteristics in
more than one category.
Mass Transport Characteristics
Mass transport is the bulk flow, or advecton of fluids through
soil. Mass transport characteristics are used to calculate
potential rates of movement of liquids or gases through soil and
include:
Soil texture
Unsaturated hydraulic conductivity
Dispersivity
Moisture content vs. soil moisture tension
Bulk density
Porosity
Permeability
Infiltration rate, stratigraphy and others.
Mass transport processes are often process-limiting for both in
situ and extract-and-treat vadose zone remedial alternatives
(Table 4). In situ alternatives frequently use a gas or liquid
mobile phase to move reactants or nutrients through contami-
nated soil. Alternatively, extract-and-treat processes such as
soil vapor extraction (SVE) or soil flushing use a gas or liquid
mobile phase to move contaminants to a surface treatment site.
For either type of process to be effective, mass transport rates
must be large enough to clean up a site within a reasonable time.
Soil Reaction Characteristics
Soil reaction characteristics describe contaminant-soil interac-
tions. Soil reactions include bio- and physicochemical reactions
that occur between the contaminants and the site soil. Rates of
reactions such as biodegradation, hydrolysis, sorption/desorp-
tion, precipitation/dissolution, redox reactions, acid-base
reactions, and others are process-limiting characteristics for
(Continued on page 12)
-------
TABLE 4. SOIL CHARACTERIZATION CHARACTERISTICS REQUIRED FOR REMEDIAL TECHNOLOGY EVALUATION
(US EPA, 1988e.f; 1989»,b; 1990; Slm» et al., 1986; Sinn, 1990; Towers et al., 1989) '
Process Site Data
Technology Limiting Characteristics Required
Process Site Data
Technology Limiting Characteristics Required
Pretreatment/ Large particles interfere Particle size
materials handling Clayey soils or hardpan distnbution
difficult to handle
Wet soils difficult
to handle
Soil vapor
extraction
Applicable only to volatile
organics ^/significant vapor
pressure >1 mm Hg
Low soil permeability inhibits
air movement
Soil hydraulic conductivity
>lE-8 cm/sec required
Depth to ground water
>20 ft recommended
High moisture content
inhibits air movement
High organic matter
content inhibits
contaminant removal
Organic matter content
In situ enhanced Applicable only to
bioremediation specific organics
Hydraulic conductivity
>lE-4 cm/sec preferred
to transport nutrients
Stratification should be
minimal
Lower permeability layers
difficult to remediate
Temperature 15-45°C
required
Moisture content 40-80%
of that at -1/3 bars tension
preferred
pH 4.5-8.5 required
Presence of microbes
required
Minimum 10% air-filled
porosity required for
aeration
Contaminants present
Hydraulic conductivity
Soil stratigraphy
Soil stratigraphy
Soil temperature
Soil moisture
characteristic curves
Soil pH
Plate count
Porosity and soil
moisture content
Thermal treatment Applicable only to organics
Soil moisture content
affects handling and
heating requirements
Contaminants present
Soil moisture content
Soil moisture content
Contaminants
present
Soil permeability
Hydraulic
conductivity
Depth to ground water
Soil moisture content
Thermal treatment Particle size affects Particle size
(continued) feeding and residuals distnbution
pH <5 and >11 causes pH
corrosion
Solidification/
stabilization
Not equally effective for
all contaminants
Fine particles < No. 200
mesh may interfere
Oil and grease >10%
may interfere
Contaminants
present
Particle size
distnbution
Oil and grease
Chemical
extraction
(slurry reactors)
Not equally effective
for all contaminants
Particle size <0.25 in.
pH <10
Contaminants
present
Particle size
distribution
PH
Soil washing
Not equally effective
for all contaminants
Silt and clay difficult
to remove from wash
fluid
Contaminants
present
Particle
size distribution
Soil flushing
Not equally effective
for all contaminants
Required number of
pore volumes
Contaminants
present
Infiltration rate
and porosity
Glycolate
dechlorination
Not equally effective
for all contaminants
Moisture content <20%
Low organic matter
content required
Contaminants
present
Moisture content
Organic carbon
Chemical oxidation/ Not equally effective
reduction (slurry for all contaminants
roflrtnrl
Oxidizable organics
interfere
pH <2 interferes
In situ Maximum moisture
vitrification content of 25% by weight
Particle size <4 inches
Requires soil hydraulic
conductivity <1E-5 cm/sec
Contaminants
present
Organic carbon
pH
Moisture
content
Particle size
distribution
Hydraulic conductivity
11
-------
many remedial alternatives (Table 4). Soil reaction character-
istics include:
Kd, specific to the site soils and contaminants
Cation exchange capacity (CEC)
Eh
pH
Soil biota
Soil nutrient content
Contaminant abiotic/biological degradation rates
Soil mineralogy
Contaminant properties, described below, and others.
Soil reaction characteristics determine the effectiveness of
many remedial alternatives. For example, the ability of a soil to
attenuate metals (typically described by Kd) may determine the
effectiveness of an alternative that relies on capping
and natural attenuation to immobilize contaminants.
Soil Contaminant Properties
Contaminant properties are critical to contaminant-soil interac-
tions, contaminant mobility, and to the ability of treatment
technologies to remove, destroy or immobilize contaminants.
Important contaminant properties include:
Water solubility
Dielectric constant
Diffusion coefficient
k"
Molecular weight
Vapor pressure
Density
Aqueous solution chemistry, and others.
Soil contaminant properties will determine the effectiveness of
many treatment techniques. For example, the aqueous solution
chemistry of metal contaminants often dictates the potential
effectiveness of stabilization/solidification alternatives.
Soil Engineering Characteristics and Properties
Engineering characteristics and properties of the soil relate both
to implementability and effectiveness of the remedial action.
Examples include the ability of the treatment method to remove,
destroy or immobilize contaminants; the costs and difficulties in
installing slurry walls and other containment options at depths
greater than 60 feet; the ability of the site to withstand vehicle
traffic (trafficability); costs and difficulties in deep excavation of
contaminated soil; the ability of soil to be worked for implemen-
tation of in situ treatment technologies (tilth); and others.
Knowledge of site-specific engineering characteristics and
properties is therefore required for analysis of effectiveness and
implementability of remedial alternatives. Engineering charac-
teristics and properties include, but are not limited to;
Trafficability
Erodability
Tilth
Depth to groundwater
Thickness of saturated zone
Depth and total volume of contaminated soil
Bearing capacity, and others.
SUMMARY AND CONCLUSIONS
The goal of the CERCLA RI/FS process is to reach a ROD in a
timely manner. Soil characterization is critical to this goal. Soil
characterization provides data for RI/FS tasks including deter-
mination of the nature and extent of contamination, risk as-
sessment, and selection of remedial techniques.
This paper is intended to inform investigators of the data types
required for RI/FS tasks, so that data may be collected as
quiokly, efficiently, and cost effectively as possible. This
knowledge should improve the consistency of site evaluations,
improve the ability of OSCs and RPMs to communicate data
needs to site contractors, and aid in the overall goal of reaching
a ROD in a timely manner.
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