EPA/540/R-94/506
January 1993
Measuring and Interpreting VOCs in Soils:
State of the Art and Research Needs
A Symposium Summary
Las Vegas, NV
January 12-14,1993
Edited By
Robert L. Siegrist
Oak Ridge National Laboratory
Environmental Sciences Division
Oak Ridge, TN
J. Jeffrey van Ee
U.S. Environmental Protection Agency
Environmental Monitoring Systems Laboratory
Las Vegas, NV
Sponsored by
U.S. Environmental Protection Agency
Organized by
Oak Ridge National Laboratory
University of Wisconsin
U.S. Environmental Protection Agency
U.S. Department of Energy
U.S. Army Environmental Center
American Petroleum Institute
December 1993
Printed on Recycled Paper
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NOTICE
The information in this document has been funded in part by the United States Environmental
Protection Agency. It has been subjected to the Agency's peer review and administrative review,
and it has been approved for publication as an EPA document.
Mention of trade names or commercial products does not constitute endorsement or
recommendation for use.
11
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CONTENTS
Page
PREFACE iv
1. INTRODUCTION 1
2. SUMMARY AND CONCLUSIONS 2
3. THE SOIL VOC PROBLEM 6
4. DECISION-MAKING NEEDS AND INFORMATION ADEQUACY 10
5. SAMPLING DESIGN ...12
6. SAMPLING AND ANALYSIS 14
7. DATA INTERPRETATION 18
8. REGULATORY FRAMEWORK 20
9. REFERENCES 22
APPENDIX A: SYMPOSIUM PROGRAM 27
APPENDIX B: LIST OF ATTENDEES 31
APPENDIX C: DISCUSSION QUESTIONS FOR THE WORKING GROUPS 36
APPENDIX D: DISCUSSIONS IN THE WORKING GROUP SESSIONS 39
APPENDIX E: BIBLIOGRAPHY 44
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PREFACE
This document contains a summary of a national symposium which included platform and poster
presentations, panel discussions, and working group sessions. An attempt has been made to
summarize the information presented and discussed, and to highlight any apparent consensus
among the Symposium participants. The summary was assembled based on information
exchanged at the Symposium. This included information from the following sources: the abstracts
and supporting papers submitted for the working proceedings distributed to the attendees at the
Symposium, the presentations and panel discussions, and the discussions during the working
group sessions. The summary was prepared and reviewed by members of the planning committee
and is believed to represent a factual account of the Symposium proceedings. As far as possible,
controversy and consensus regarding the state-of-the-art and -practice have been described as well
as current research needs. Many details were necessarily omitted, however, and for in-depth
treatment of any particular subject, the reader is directed to appropriate literature cited in the
references or bibliography sections of this document.
Many individuals contributed significantly to the conduct of the Symposium. Gratefully
acknowledged is the diligent work of the following members of the Symposium planning
committee:
Bruce J. Bauman
Ruth Z. Bleyler
David W. Bottrell
Patrick D. Eagan
Joan F. Fisk
Duane A. Geuder
Roger A. Jenkins
Eric Koglin
Martin Stutz
American Petroleum Institute, Washington, D.C.
U.S. Environmental Protection Agency, Washington, D. C.
DOE Office of Technology Development, Washington, D.C.
University of Wisconsin, Madison, Wisconsin
U.S. Environmental Protection Agency, Washington, D. C.
(On an IP A assignment with Los Alamos National Laboratory)
U.S. Environmental Protection Agency, Washington, D. C.
Oak Ridge National Laboratory, Analytical Chemistry Division,
Oak Ridge, Tennessee
U.S. Environmental Protection Agency, Environmental
Monitoring Systems Laboratory, Las Vegas, Nevada
U.S. Army Environmental Center, Aberdeen Proving Ground,
Maryland
These members were not only critical to establishing the content and organization of the
Symposium, but were also active participants in it. Many presented papers, appeared on panels,
led working group sessions, and/or wrote summaries of the Symposium. Their support and
enthusiasm contributed to the success of this meeting. Appreciation is also extended to Dean
Neptune, Neptune & Company, for chairing and summarizing a working group session.-
Several individuals prepared summaries and critiques of the Symposium for consideration in
preparing this Symposium summary and they are acknowledged for their contributions:
Dr. Neil Hutzler Michigan Technological University, Houghton, Michigan
Dr. Thomas Spittler U.S. Environmental Protection Agency, Lexington, Massachusetts
Fred Cornell Environmental Liability Management, Inc., Princeton, New Jersey
David Goldblum Consultant, San Antonio, Texas
The authors acknowledge all of the Symposium participants who contributed by attending and
actively participating not only during the formal presentations, but during the late afternoon and
evening working group sessions. Finally, Pat Eagan of the University of Wisconsin-Madison was
responsible for the logistics. The Symposium ran smoothly and for this, everyone is extremely
grateful.
IV
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1. INTRODUCTION
Volatile organic compounds (VOCs)
encompass a broad class of chemicals that
includes benzene, methylene chloride, and
trichloroethylene, as well as many other
solvents, petrochemicals, and agrochemicals.
As a result of their widespread and intensive
usage over the years, VOCs are the most
prevalent chemicals at contaminated sites
across the United States and abroad. The
adverse effects of VOCs vary widely
depending upon the compound or mixture in
question, source concentrations, transport
pathways, and human and environmental
exposures. In a majority of cases, soil and
ground water contaminated by one or more
VOCs are the primary focus of major
characterization, assessment, and remedial
actions.
Substantial funds are being expended on
VOC sampling and analysis, and significant
site assessment decisions and remedial
actions have occurred and are ongoing. For
VOC contaminated sites, however, the
conventional measurement and interpretation
process may not adequately address sources
of error that can severely hamper the overall
effectiveness of site assessment and remedial
action. Problems result from the unique
properties and behavior of these compounds
and the manner in which they may move in
soil, a complicated system of solids, liquids,
and gases. As a result, the effective
characterization and assessment of
contaminated soil is constrained by spatial
and temporal variability and by sampling and
analysis errors.
A symposium on "Measuring and
Interpreting VOCs in Soil - State of the Art
and Research Needs" was held in Las Vegas,
Nevada on January 12-14, 1993 (Appendix
A). The Symposium was attended by
approximately 300 people, representing a
wide variety of interests, backgrounds, and
disciplines (Appendix B). The geologists,
chemists, engineers, hydrologists, and
environmental scientists that generate data on
VOCs in soil were brought together with the
risk assessors and engineers who need the
data to evaluate risks and to design and
implement cleanup technologies. During three
days of formal presentations and working
group sessions, the participants:
• Explored the foundation of the
conventional VOC measurement and
interpretation process,
• Examined results from research and
practice that have advanced the
understanding of this process,
• Discussed whether data from hazardous
waste sites are adequate for addressing
the multiphase distribution of VOCs in
soil, and
• Attempted to develop a consensus on the
state of the art, recommendations for
current practice, and critical research
needs.
At the beginning of the Symposium, each
participant received a proceedings notebook
that contained extended abstracts and
supporting publications for platform and
poster presentations describing:
• Behavior of soil VOCs and implications
for measurement,
• Validity of conventional VOC
measurements for risk assessment
purposes,
• Soil sample collection and handling
techniques,
• Sample analysis techniques for mobile
and fixed-base laboratories,
• Utility of onsite screening techniques,
• In situ VOC measurement devices and
methods,
• Conventional and alternative quality
control strategies,
• Data analysis and interpretation for risk
assessment and decision making, and
• Innovations in measurement techniques
and assessment approaches.
A list of critical questions was prepared by
the planning committee and provided to the
participants to foster meaningful discussion
during the Symposium (Appendix C). Some
of the questions were addressed during a
series of working group sessions and the
results from those sessions are summarized
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in Appendix D.
The purpose of this document is to.
summarize the key issues discussed and
conclusions reached at the Symposium. The
measurement and interpretation of soil VOCs
are described herein in a comprehensive
manner with due focus on whether the data
being collected and reported are sufficient to
meet the needs of the data user. As far as
possible, controversy and consensus
regarding the state-of-practice and
-knowledge have been highlighted in this
summary. Current research needs are also
outlined. Many details were necessarily
omitted. For in-depth treatment of any
particular subject, the reader is directed to
appropriate literature cited in the references or
bibliography sections of this document.
2. SUMMARY AND CONCLUSIONS
During the Symposium many issues were
raised and discussed related to measuring and
interpreting VOCs in soils (Table 1, Appendix
C and D). There was consensus that current
practices were seriously flawed in many areas
and that results of recent research and practice
provided a sound basis for change.
Based on the presentations and discussions at
the Symposium, the following conclusions
were drawn.
2.1 State-of-the-Art and -Practice
Behavior and Measurement Process ~
• The classification of VOCs is somewhat
arbitrary and includes a variety of organic
compounds that possess widely varying
properties and behaviors in soils.
• VOCs in soil are unique due to their
prevalence, multiphase behavior, and
potential adverse public health and
environmental effects. They often are the
principal contaminants of concern and
determine the need for and nature of
remedial actions at a given site.
• Decision-making needs and adequacy are
incorporated in the data quality objectives
and data assessment process. The
adequacy of data is largely dependent on
the potential for and impact of making an
erroneous decision. Errors in
measurement and interpretation of VOCs
in soils include (1) real spatial and
temporal variations that are not adequately
characterized due to the normally limited
number of sample locations and.
observations, or (2) errors due to soil
VOC sampling and analysis and data
management. A comprehensive and
robust model for allocating error among
various process activities is currently
unavailable.
• Design of sampling and analysis
programs must be based on the
question(s) to be answered and the
potential decisions to be made within the
context of decision support zones (i.e.,
volumes of soil). Naturally large spatial
variability in soils can lead to wide
variation in soil VOCs over short
distances. To define this variability, high
sampling densities and spatially disperse
data are needed.
• Measurements of ancillary soil properties
(e.g., water content, organic carbon
content) can provide valuable
complimentary insight into spatial
variability and soil VOC behavior. This
information can enhance decisions made
regarding characterization, assessment,
and remedial actions for soil VOCs.
Sampling and Analysis —
• Ground surface and in situ diagnostic
tools provide a valuable method for
examining soil regions and defining
decision support zones. Measurements
of VOCs in soil vapor have been widely
used for diagnostic purposes. They are
not as quantitative for total VOCs as bulk
soil matrix measurements if the latter are
properly done.
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Table 1. Examples of relevant problem areas and issues discussed at the Symposium. £
Area
Some issues discussed
Perceived problem *
Decision-making needs •
Sampling designs •
Measurement techniques •
Data interpretation •
Regulatory framework •
Purpose of VOC measurements, overall problem and significance,
technical facets, and institutional facets.
What are the questions to be answered, decision quality versus
data quality, risk analysis requirements and use of field data.
Definition of decision support zones, reconciliation of diverse data
and information sources, requirements and use of ancillary data.
Diagnostic techniques to define regions of interest, sample
acquisition methods, utility and methods of sample compositing,
sample screening and infield analyses, sample containerization for
off-site analyses, accuracy and precision of VOC analyses.
Role of formal data validation, treatment of values near the
detection limit, statistical treatment of spatially and temporally
disparate data, visualization methods.
Requirements versus guidance, how practices can be changed.
3 Refer to Appendix C for discussion questions and Appendix D for working group responses.
Soil samples should be acquired with as
little disruption as possible during
collection and handling. The subsample
for analysis should be removed from the
bulk soil sample in an intact state and
quickly transferred to the analysis vessel
in a single step, either in the field or in the
laboratory. This subsample transfer
should be made as soon after collection as
possible.
The use of direct-push sampling
technology can acquire intact bulk soil
samples at depths of 30 m or more with
less disruption and lower cost than
conventional drilling and split-barrel
Sampling methods.
Far greater emphasis must be placed on
the use of field analytical methods for
providing data for decision-making
purposes. Field methods offer the
potential of providing increased spatial
and temporal information more rapidly
and at reduced cost.
Laboratory analytical results are not
inherently superior to field analytical
results. However, quantitative field
analytical methods must be distinguished
from qualitative field screening methods.
There is need for an effective program
that provides for timely evaluation and
approval of field analytical methods.
Field measurements of some, perhaps
many, soil VOCs can be made with an
accuracy equivalent to a fixed base
laboratory by using available and
affordable field gas chromatographs
(GCs) with water immersion and
headspace methods.
Field analytical data can be used for
significant decision-making, including
quantitative risk assessment, as long as
this intention is clearly incorporated into
the data quality objectives process.
Portable instruments, sensors, and test-
kits are emerging, for on-site and in situ
measurement, that provide adequate
information more rapidly and at lower
cost. In selecting an emerging field
method, it is important to consider data
quality objectives and the method
accuracy, precision, and interferences.
Soil samples collected by conventional
practices (i.e., disrupted soil placed in
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sealed containers and refrigerated at 4°C
with subsequent laboratory subsampling
and analysis) will normally yield VOC
concentrations that are significantly
different than the true in situ
concentrations. Significant losses of
VOCs (up to 90% or more) have been
reported due to volatilization caused by
sample disruption during field or
laboratory subsampling, as well as due to
leakage and/or transformation during pre-
analytical holding. These losses have
been observed for both halocarbons and
petroleum hydrocarbons. These losses
can be mitigated by sample collection and
transfer with coring devices and through
unproved preservation methods.
• Improved preservation of soil VOCs
beyond that afforded by low temperatures
can be achieved by either onsite
immersion of the sample in an organic
solvent (methanol is commonly used) or
containerization in a closed-vial analysis
vessel. The former method is most
appropriate for high concentrations of
VOCs and offers potential for indefinite
holding and high extraction efficiencies.
It does suffer from field handling of a
potentially hazardous material and
dilution of 10- to 100-fold during
analysis. The latter method is most
applicable for low concentrations and
offers low detection limits. Since dilution
is precluded, however, samples with high
VOC concentrations can swamp the
analytical instrument.
• Compositing of soil samples seemingly
can be employed to more cost-effectively
establish, and to some degree,
characterize decision support zones.
Further work is required to assess the
detection limit and matrix interference
questions, however.
• Some VOCs may become physically
entrapped in the microstructure of soils
and be difficult to desorb and remove
during conventional purge-and-trap
extraction. This may result in
underestimation of the concentration of
soil VOCs in the soil matrix. Disruption
of the soil macro- and microstructure may
be required to recover these entrapped
VOCs.
Data Assessment and Interpretation --
• Data assessment must answer questions
regarding data quality, adequacy, and
acceptability. This is normally done
within a regulatory and contractual
framework that focuses on laboratory
analyses. Depending on the type of data
and the depth of assessment, costs for
validation can range from three to ten
times the analytical costs. While
validated laboratory analyses are costly,
they can be of little value if sampling and
handling yield substantial and significant
bias, or if discrete samples do riot
represent the region of interest.
• Interpretation must reconcile and integrate
the various elements of a soil VOC data
set (e.g., field screening, on-site lab
analysis, off-site lab analysis, physical
site conditions, etc.). The emphasis on
the analytical portion of the soil VOC
measurement process has inappropriately
focused on discrete values rather than on
comprehensive data sets and information
packages.
• Uncertainty exists with prediction of
VOC concentrations at un-sampled
locations. Due to normal subsurface
heterogenieties combined with the
complex behavior of VOCs, true soil
concentrations at unobserved locations
may deviate by one or two orders of
magnitude from those predicted based on
measurements at an adjacent but separate
location. This situation further
emphasizes the need for and value of
diagnostic measurements (e.g., in situ
soil gas) and field screening of spatially
disperse samples (e.g., with field
immunoassay tests).
• A serious shortcoming with the current
process of characterizing soil regions for
VOCs may be the limited number of
samples often collected from which
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inferences are made (e.g., one, 5-cm3
sample per 50 m3 of soil). While spatial
correlations and geostatistical techniques
can provide some measure of uncertainty,
no statistical tool will overcome the lack
of spatial information provided in a
limited data set.
• Interpretation of soil VOC data is often
fraught with difficulties due to inherent
problems with the measurement process
coupled with inadequate planning and
communication across all involved
disciplines. For example, a question
often remains as to whether a given
measurement method is appropriate to
answer questions regarding the exposure
pathways of concern.
Improving Past Practices --
• Despite recent advancements, serious
deficiencies remain in practices
commonly used for measurement and
interpretation of soil VOCs. Changes are
warranted and should be made within the
context of total quality management.
There is new knowledge to infuse into an
existing process to improve its efficiency
and effectiveness. In many cases, the
information base is adequate to support
change and there is flexibility in many
regulatory programs to permit change.
• Modifications to conventional practices
are being adopted as standard practices by
standards-setting agencies and being
mandated for use by some state
regulatory agencies. An example is
ASTM method 4547, standard practice
for sampling waste and soils for volatile
organics (includes limited disruption
subsampling by coring and in-field
immersion in methanol).
• Modifications to standard analytical
methods are also being implemented. In
the Third Update to EPA SW-846 a new
procedure will be included for solid
matrices that employs an automated
purge-and-trap system which agitates the
sample within the original collection
vessel during the purge step (new SW-
846 method 5035). This method
enhances VOC preservation and recovery
efficiency.
• There is great concern over the lack of a
clear process for getting approval to use
improved practices. This is of particular
concern for individuals who must
complete sampling and analysis projects,
but are unable to use new methods.
• While erroneous conclusions may have
been reached regarding soil VOC
concentrations at a given site, it is
uncertain what the adverse impacts may
have been on decisions regarding the
nature and extent of contamination, need
for cleanup, and/or verification of cleanup
achieved.
2.2 Research Needs
Despite a considerable body of research and
experience in measuring and interpreting
VOCs in soil systems, further research is
necessary and appropriate in several areas as
outlined below.
• The interactions of VOCs of differing
properties with mineral and organic
materials in soil need to be assessed in
light of current and future methods of
sampling and analysis. The potential for
matrix diffusion and intraparticle
entrapment and their effects on
measurement accuracy need to be
elucidated.
• There is a need to elucidate the spatial
and temporal variability typically
encountered with soil VOCs under
different conditions. This information is
needed to better understand the degree of
accuracy and precision appropriate for
assessing a given soil region.
• Continued research and development are
needed to yield field screening and
analytical methods of known and
predictable performance for measuring
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different VOCs in different soil media.
Controlled laboratory and field
experiments are needed to rigorously
evaluate the stability of VOCs of widely
differing properties as affected by
containerization and preservation
techniques. Methods to increase the
stability of samples to long time frames
would provide more accurate VOC data
and also facilitate sequential analysis of
samples and sample archiving.
To help address spatial variability issues,
technically viable methods of
compositing soil samples for analysis of
VOCs need to be developed. Issues of
matrix interferences and detection limit
constraints need to be resolved.
There is a need for a comprehensive
error model that defines the different
error components for soil VOC
measurements at a single point in space
and time and for multiple measurements
within a soil region of interest.
QA/QC strategies and methods need to
be analyzed to determine the most cost-
effective process. Alternatives include
use of performance evaluation materials
and referee laboratories.
The relative importance of accurate
measurements of discrete samples must
be evaluated in light of the great
uncertainty and error potential within
risk assessment and remedial action
decision-making. This is important
given that the uncertainty associated with
risk assessment can be several orders of
magnitude greater than that of the
characterization process itself.
3. THE SOIL VOC PROBLEM
VOCs are the most prevalent contaminants at
many hazardous waste sites in the U.S. and
abroad (Table 2) (4,31,43,51,63). They are
significant in that they are often mobile and
persistent in soil environments and frequently
contaminate extensive regions of soil and
ground water. They may also contaminate
ambient air and nearby surface waters.
Inherent properties of the compounds vary
widely as do their mobility in various media
and their potential health effects (18,29,32,33,
51, 61, 90).
An understanding of soil and how VOCs
behave within it is important to understanding
the degree and rate at which VOCs can
migrate and lead to potentially harmful
exposures to humans and the environment.
While most investigators focus on measuring
the highest concentration of VOCs that may
be extracted from the soil in virtually any
phase, it is most important in the risk
assessment and remedial action process to
understand the soil system and the phase
distribution of VOCs. This enables better
characterization of transport and fate
processes and exposure pathways, and
enhances evaluation of remediation options.
Soil is normally considered to be the fine-
earth fraction of geologic material (e.g., < 2
mm) (3,6,8,48,61). It is a complex media
comprised of solid, liquid, and gaseous
phases which interact in a dynamic
equilibrium. Soil is a heterogeneous material
with properties varying at different spatial
and temporal scales (Fig. 1-2, Table 3). At
some hazardous waste sites, "soil" may
actually be a poor description of the solid
material being sampled. In the sampling of
soil and soil-like material, particle size is
important as is the composition, both of
which may vary over a range of spatial
scales.
Volatile organic compounds in soils are
typically present in several phases (Fig. 1)
(29,32,51,61). The compounds maty be
adsorbed to or absorbed in the soil, and the
compounds may exist in the interstitial spaces
as liquids or vapors. The degree and rate at
which the compounds partition within and
migrate through soil depends on the
properties of the compound and the soil
system. A detailed discussion of these
factors may be found in several excellent
reviews (e.g., 29, 51, 61).
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C/olatilization to soil
or atmosphere
Fig. 1. Illustration of the partitioning and potential inteiphase transfers of VOCs in soils (after 51).
Soil VOCs pose significant challenges to the
investigator who seeks to assess the risks
they pose to human health and the
environment. The accurate measurements
necessary for assessment purposes are
difficult to achieve since VOC concentrations
in soils vary widely in space and time, and
measurements are subject to considerable
random and systematic error (3,12,15,21,25,
35, 37,43,44, 51,52, 63). The goal of an
investigator of a hazardous waste site is to
obtain measurements of VOCs that are
sufficient to meet the needs of the decision-
makers, including those who must assess the
risk to human health and the environment and
those who select, design, and implement a
remedial action.
Variability in the measurement of VOCs can
be disturbingly large (e.g., 1 to 3 orders of
magnitude) as a result of natural variability
and measurement errors even when standard
measurement techniques are employed (Fig.
2) (43, 51, 52,63). The distribution of VOCs
in soil can be quite variable as a function of
time and space (6, 9, 18, 44, 48, 51, 68, 89).
m...
spatial
100m2
Fig. 2. Illustration of spatial and temporal
variability and measurement error potential
within contaminated soil regions (64).
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Table 2. Some volatile organic compounds included within the Target Compound List (TCL) in
the USA and their occurrence at Superfund Sites (after 63).
Compound
Vinyl Chloride
Methylene Chloride
Acetone
1, 1-Dichloroethene
1 , 1 -Dichloroethane
trans- 1 ,2-Dichloroethene
Chloroform
1 ,2-Dichloroethane
2-Butanone
1 , 1 , 1-Trichloroethane
Carbon Tetrachloride
Trichloroethylene
Benzene
2-Hexanone
Tetrachloroethylene
1 , 1 ,2,2-Tetrachloroethane
Toluene
Chlorobenzene
Ethylbenzene
Styrene
m-Xylene
o-/p-Xylene
Molecular
weight
g/mol
62
85
58
97.0
99.0
97.0
119.4
99.0
72.1
133.4
153.8
131.5
78.1
100.2
165.8
167.9
92.1
112.6
106.2
104.1
106.2
106.2
Boiling
point
°C
-13.9
40
56.2
31.9
57.3
48
62
83.5
79.6
71/81
76.7
86.7
80.1
128
121.4
146.4
110.8
132
136.2
145.2
139
144.4
Properties &
Vapor
pressure
mm
2660 (25°C)
349
270 (30°C)
500
180
200 (14°C)
, 160
61
78
100
90
60
76
2
14
5
22
8.8
7
5
6
5
Occurrence
Aqueous rank and
solubility frequency ^
mg/L
1100(25°C)
20000
Miscible
5500
600
8000
8690
353000 (10°C)
4400
800
1100(25°C)
1780
35000
150 (25°C)
2900
515
500
152
300
175
23 [8%]
18 [10%]
20 [9%]
19 [10%]
17 [12%]
6 [20%]
25 [7%]
8 [17%]
27 [7%]
1 [35%]
5 [23%]
9 [17%]
3 [27%]
26 [7%]
15 [12%]
14 [13%]
it
S Properties are at 20°C unless another temperature is shown in ( ).
k Rank (highest =1) and prevalence [% of sites] based on a total of 466 different substances found at the 888
Superfund sites (as of October 1986).
Table 3. Typical distributions of soil properties important to VOC behavior (68).
Soil property
Distribution Average ^
Std. dev.
Total volumetric porosity (v/v)
Volumetric water content (v/v)
Fractional organic carbon content (wt./wt.)
Normal . 0.373
Log-normal 0.048
Log-normal 0.028
0.09
2.
3.17
& Geometric mean and standard deviation are given for log-normal distributions.
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As a result, closely spaced samples can yield
dramatically different VOC concentrations.
Measurement variability and bias can also be
large. A common problem is negative bias
due to large losses of the VOCs before the
sample is analyzed, and incomplete extraction
of the VOCs from soils at the time of analysis
(43,50,51,63,71). Positive bias may also be
present where compounds are created as a
result of biological and chemical
transformation processes, or where
compounds are mistakenly reported as a
result of interferences or gross errors in the
analytical phase. Negative bias can greatly
influence the risk assessment process by
underestimating the potential risks to human
health and the environment.
Measurements are made to support decisions
and the various sources of variability and
error may or may not adversely affect a given
decision or subsequent action (Fig. 3). An
investigator may take precautions to minimize
the bias and variability in the measurement
process. But typically an accurate
assessment of bias and variability is lacking
because of difficulties in accurately
measuring VOCs in soils. Often, an
investigator is unaware of the bias and
variability that may be tolerated in a risk
assessment process. Consequently, an
investigator may try to obtain what is thought
to be the best available VOC data by
concentrating time and money on the
analytical phase. Frequently, the bias and
variability in the analytical phase of the
measurement process, is only a small part of
the uncertainty and error associated with
characterization of VOCs in soil regions (12,
15, 52, 44, 63).
A benchmark that is used to evaluate
acceptable levels of contaminants in soil is
frequently referred to as an "action level".
Concentrations of VOCs in soil that are
reported above the action level are presumed
to be unacceptable, and a variety of actions
may be triggered. Generic "action levels" for
VOCs in soil have been difficult to establish
because site-specific factors and various soil
types can greatly influence the risks that
might be created from soil that is
contaminated at a particular concentration.
Even if action levels are prescribed* an
equally important parameter often is not.
This is the volume or mass of soil within
which the concentration of contaminant is
sampled, measured, or is of concern. A
reported action level without a corresponding
soil volume, can be virtually meaningless in
characterizing a region of interest.
w 1 • TRUE CONCENTRATIONS ) „,
*" 1 In Domain of interest ^
1
SAMPLING DESIGN ,
• Data Quality Objectives
• Site Conditions
• Implementation
• Constraints
Natural and
Man-Induced
Variation
1
T
SAMPLING COLLECTION '
• Research Sampling Point
• Bulk Sail Removal
• Collect Field Sample (25-150 g)
• Containerize Sample
• Preserve Sample
• Transport and Store Sample
• Field OA/OC Samples
1
SAMPLING ANALYSIS '
Laboratory Sample Storage
Laboratory Subsampllng (1-5 g)
Analysis Preparation
Laboratory QA/QC
Sample Analysis
Data analyysls and Reporting
|
MEASUREMENT INTERPRETATION
Measurement
Crror
Interpretation
Error
i
f * ^
I MEASURED CONCENTRATIONS
1 In Domain of Interest I
Fig. 3. Illustration of a conventional
measurement process for VOCs (after 62 - 64).
-------
The volume of material being sampled is
often referred to as the "support". The
volume of material being analyzed is always
significantly smaller than the volume of
material being sampled. These small sample
volumes are typically used to make inferences
about the characteristics of larger volumes of
material at a site. These larger volumes are
increasingly being described in terms of
units, e.g., "decision unit", "exposure unit",
and/or "distribution unit". Like most
contaminants being sampled and measured in
soils, VOCs must be carefully measured and
reported with significant attention devoted to
the "support" and the "units" of soil being
assessed throughout the measurement
process.
Analytical methods measure the concentration
of a contaminant in a soil sample that may be
as small as 1 to 5 grams. This sample may
come from a soil core that is supposed to
represent the volume of soil in a "decision
unit" or "exposure unit" that may be 100 m3
or more in size. Homogenization and
compositing of samples are means for
increasing the "representativeness" of the
sample, but these processes have so far been
especially difficult to employ in VOC
sampling. Due to analyte losses, they may
lead to samples that are actually less
representative of actual site characteristics.
For example, reducing the particle size of a
soil core sample by grinding so that any
subsample is comparable to another may
dramatically alter the concentration and phase
of the VOC contaminants in that subsample
relative to actual site conditions. Data from
soil samples that are treated in this way may
be input into risk assessment, transport and
fate, or treatabUity models and yield very
misleading results.
For characterizing larger spatial scales,
compositing or statistical "averaging" of
samples may be required due to resource
limitations. However, with soil VOCs,
simple compositing or averaging may
obfuscate the identification of important
small-scale features such as "hot spots."
Reported concentrations for an area may be
significantly less than the concentration of
contaminants in hot spots. Important
features, such as stringers and layers of soil
contaminated with VOCs, may also be
completely missed or misrepresented.
4. DECISION-MAKING NEEDS
AND INFORMATION ADEQUACY
All too often the basic questions to be
answered by a sampling and analysis
program have been poorly stated and defined.
Sampling efforts are frequently developed to
define the extent of contamination at a site
and to determine whether the contamination
exceeds an action level (3,6,12,28,48,68).
Resources are often allocated to the sampling
effort with little thought being given to
acceptable error rates and margins for error in
the site characterization effort. Important
volumes, e.g. support, exposure units, and
decision units, are often not defined.
Tradeoffs between the collection of more data
to better define the nature and extent of
contamination, versus remediating portions
of the site, are often made poorly or not made
at all.
Defining exactly what data is needed and how
good the data must be for various purposes
(e.g., risk assessment, engineering design,
process monitoring and control) is frequently
done too late in the characterization and &
monitoring process. The necessary and
appropriate scientific and technical disciplines
(e.g., analytical chemists, lexicologists,
statisticians, quality assurance specialists,
engineers, lawyers) are frequently not
assembled into a team at the beginning of the
project to help define basic questions.
Instead, they are independently consulted at
various stages of the process and often at
stages where they have little ability to review
the basic questions and determine whether
those questions will be addressed efficiently
and economically.
Increasing attention is being paid to the
development of data quality objectives
(DQOs) at an early stage in a site
characterization effort (28,77,85). All too
often, however, DQOs are narrowly
developed and focused on the analytical
phase of the process. Precision, accuracy,
representativeness, completeness, aind
10
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comparability are addressed with emphasis
on the analytical phase. Little effort is
devoted to an analysis of the number, type
and quality of data that will be required to
meet the needs of the decision-maker in
answering basic questions.
Exposures to contaminants at hazardous
waste sites depend on contaminant sources,
transport pathways, and activity patterns (86).
A person or species may spend part, or all, of
its life at a point where direct exposure to a
contaminant can occur. In other cases, the
contaminant in the soil must be capable of
migrating to a point where it can come into
contact with the person or species. VOCs
can move through the environment in many
ways, including transport as nonaqueous
liquids, aqueous constituents, vapors, or
particle-sorbed compounds.
The exposure pathways of concern contribute
significantly to the decision-making needs
and must be considered in establishing the
measurement process. For example, if the
exposure pathway of concern was the
migration of vapors through the subsurface
because the vapors might enter basements,
manholes, and underground utility corridors,
then sample collection and analytical methods
that assess the amount of VOCs that are
present, or may develop, in the interstitial
spaces of the soil would be most appropriate.
Similarly, if the exposure pathway of concern
was contamination of groundwater used for
drinking water, then methods using a
aqueous extractant to determine the soil
VOCs that would leach into ground water
over time would be appropriate. To assess
the risk from soil ingestion, bulk soil samples
could be collected and extraction done with a
technique designed to mimic the desorption
that occurs during and following ingestion.
In contrast, for some modeling purposes,
total soil VOCs must be quantified using bulk
sample collection and more aggressive
extraction techniques, possibly using an
organic solvent or supercritical fluid. In each
exposure scenario some consideration must
be given to the volatile organics of concern
and the soil morphology and chemistry. The
goal is to select a measurement process that is
most appropriate to answer basic questions
regarding exposure pathways for VOCs.
No measurements of soil VOCs are made
without some prior knowledge of the site.
This knowledge is used formally, or
informally, to determine locations where
samples are collected. Each source of data
carries with it the potential for bias and
variability. The quality of the data influences
in varying degrees the basic decisions that are
made about the site. It is likely that no single
data point and single observation will
determine the degree to which resources are
spent to further investigate a site and to
remediate the contamination. If this were the
case, the quality assurance/quality control
(QA/QC) program for the site investigation
would have to be quite rigorous. It would
not be enough to ensure that the analytical
portion of the study were producing data of
high accuracy and precision, without
ensuring that the samples were properly
collected. In reality, critical decisions on
hazardous waste sites are usually made with a
minimum number of data from different
sources with the goal being to have a
preponderance of information that leads to a
high quality decision.
There are several ways to reduce the risk of
making an incorrect decision in characterizing
soil VOC contamination at a hazardous waste
site. One way is to divide the site up into
smaller areas where a risk of making an
incorrect decision in a given area will not be
catastrophic overall. Another is to obtain
more discrete data. Another is to obtain less,
but more "representative" data. This may
involve compositing of samples if the basic
objective for the study allows this. Another
waiy is to improve the quality of the data.
A major source of bias and variability in VOC
measurements in discrete samples is the loss
of volatiles from sample collection to
analysis. Soil matrix effects can also be a
factor. Field screening methods that can
generate data at relatively low cost and with
minimal delays may be superior to more
conventional laboratory measurements even if
the analytical methods are judged to produce
more representative, more accurate, and more
precise data. Research has shown that large
bias and variability occurs before a sample is
analyzed and this error can overwhelm the
11
-------
error present in many currently prescribed
laboratory methods (35,37,43,47,65,75).
Loss of volatiles begins from the time a
sample is collected to the time it is analyzed.
The losses may be from biological
degradation, chemical transformation, or
outright losses of the sample. A sample that
is analyzed soon and with little disruption is
more likely to be representative of actual site
conditions.
Decision-making needs and information
adequacy must be considered within the
overall perspective of the characterization and
assessment process. It can be argued that
due to a high degree of uncertainty present in
exposure scenarios and health effects (i.e.,
orders of magnitude) coupled with potentially
great spatial variability, striving for accurate
and precise quantitation of VOCs in discrete
soil samples is unfounded and unnecessary
(12,15,44,49,68). If one were to generalize,
the relative uncertainty and error in the
characterization and assessment process
could be ranked from high to low as follows:
exposure/health effects >»
spatial variability > >
sampling and handling > >
analysis.
Depending on the decision to be made, an
investigator should place appropriate
emphasis on the sampling design, soil VOC
measurement methods, or data interpretation
process.
5. SAMPLING DESIGN
A major objective of sampling design is to
yield measurements that satisfy the DQOs
established (20,21,28,77). This normally
involves measuring concentrations of VOCs
in regions of interest that are representative of
the true concentrations present (Fig. 3). To
accomplish this, the design process must
address the phase distribution of soil VOCs,
real spatial and temporal variability, and
measurement variability and error. Many
decisions must be made, including
determining a measurement strategy (e.g., in
situ soil gas survey, collection/analysis of
discrete samples from a 3-dimensional grid),
the number and placement of sample
locations, the frequency of sampling, and the
analyses to be completed. If done properly,
decision-making based on the data generated
will not be flawed by the measurement
process. For example, if VOC
concentrations truly exist that would pose
unreasonable risks to human health and the
environment, they would be measured and a
correct decision made.
Data from individual sample locations are
frequently clustered to make decisions on
areas of a site (e.g., decision support zones).
A "remediation unit" can be described as the
smallest unit of soil to be treated or
remediated if the measured concentration
within the unit exceeds a particular level. An
"exposure unit" is a portion of a site where
present or future exposures of humans or
species would exceed acceptable levels of
risk.
Error (i.e., measured concentrations ^ true
concentrations) is a fundamental part of the
measurement process. The sampling design
should ideally provide for an estimate of the
uncertainty and error in the measurements
made (20,21). A key question is what are the
sources of error and how much error can be
tolerated in the measurement process while
still allowing for reasonably correct
decisions.
The assessment of error in the measurement
of VOCs in soils is complicated. Few soil
standards exist. Standard analytical methods
often do not provide consistent, accurate
results when known concentrations of VOCs
are introduced into soils, and the soils are
subsequently measured. The concentration
and nature of the compound, matrix effects,
and the chosen analytical technique contribute
to the bias and variability. How, then, can a
sampling design enable an assessment of bias
and variability in soil VOCs at a given site?
Methods have been proposed for QA/QC
programs that can provide quantitative
assessments of error at various stages of the
sample collection and measurement process
(42, 89). A comprehensive approach,
12
-------
developed primarily for conservative
contaminants such as metals in soil, may be
adapted to VOCs in soil. In this approach
emphasis is placed on the identification of
batches and the placement of a variety of
QA/QC samples in the batches during an
investigation to assess and track the errors.
QA/QC samples, such as collocated samples
and split samples, can be used to provide
estimates of analytical precision, but
estimates of sampling bias are more
complicated.
The assessment of bias requires soil samples
with known concentrations of contaminants.
Making representative "evaluation samples"
is difficult for metals in soil and even more so
for VOCs in soils. Controlled spiking of soil
with VOCs to yield representative partitioning
within the soil matrix is difficult and highly
variable, as is the subsequent recovery of the
VOCs. Changes in VOC concentrations can
occur at the time the soil is spiked and
continue until the time the sample is analyzed.
The use of surrogate spikes may not provide
a true measure of VOC recovery in the purge
phase because they are only introduced to the
soil with the internal standards immediately
prior to analysis.
Advocates of the use of organic solvents,
such as methanol, to preserve and extract
VOCs in soil, offer a technique that allows
evaluation samples to be readily created.
Double- and single-blind QA/QC samples can
be created by spiking VOCs into the methanol
solution in a sample vial, rather than trying to
spike the soil itself.
There are many considerations in assessing
the impact of errors in the measurement of
VOCs in soil. If the measured concentration
of VOCs is clearly above a concentration of
concern (or action level), then it is unlikely
that good estimates of error will be required,
especially if a negative bias is a common
error. The VOC data will support needed
action. However, if the measured VOC
concentrations are near an action level and the
consequences from making a wrong decision
are great, then the importance increases for a
rigorous QA/QC program to assess the error
and variability in the data. A QA/QC
program that attempts to assess errors
throughout the entire sample collection and
measurement process becomes more
important.
Sampling designs should enable the
integration of VOC analytical results with
general geologic and meteorological
information. This is important to better
understand the VOC occurrence, transport,
and fate and to put the VOC sample data into
proper perspective. Samples corresponding
to those used for VOC analysis should be
analyzed for other important properties (e.g.,
texture, water content, organic carbon
content). This information will help answer
important questions. For example, were the
samples collected in a soil horizon that is
important to characterize for the assessment
of potential exposure pathways? Did the
rain, wind, or temperature affect the sampling
program and the collection of the samples?
Clearly, a number of factors need to be
assessed in conjunction with the assessment
of the data from the VOC analytical phase.
Sampling designs need to include far greater
emphasis on collection of spatially disperse
sample data of "acceptable quality" to
enhance the overall characterization within a
site and its decision support zones. This can
be best accomplished using on-site, real-time
methods taking advantage of new
technologies such as hydraulic probes, in situ
detectors, and field analytical instruments.
While simple screening procedures (e.g.,
hand-held photoionization detectors for
headspace measurements) have been used to
provide qualitative information,
advancements in sample acquisition
equipment and field analytics need to be
incorporated in quantitative decision making.
It must be recognized that meaningful data
can be achieved with improved field
instruments and procedures (e.g., field-
portable gas chromatographs). Continuing
development of chemical and immunpassay
test kits will likely provide attractive
advantages for field analysis of VOCs.
The sampling design must ensure that the
data generated will be useful with respect to
answering the basic questions that were
identified in the early DQO stages of the site
investigation. For example, does the bias
13
-------
and variability in the VOC data significantly
affect the basic assumptions and models that
are being developed to estimate the risk to
human health and the environments? Do the
assumptions made in the risk assessment
process and the evaluation of remediation
measures warrant the collection of more data,
or better data? These questions are best
addressed by a team approach where all
parties involved in the investigation are
willing to accept the fact that uncertainties in
the data may be great. Specific actions then
can be taken to further resolve the basic
questions that were identified early in the site
investigation process.
6. SAMPLING AND ANALYSIS
Measurements of soil VOCs can be made
with varying degrees of quantitation certainty
and specificity (13,26,30,31,42,46,54,58,69,
70,74,79). The VOC measurement process is
illustrated in Fig. 3 while the current soil
VOC sampling and analysis paradigm is
depicted in Fig. 4. The current soil VOC
paradigm emphasizes the character and
quality of discrete data points by employing
bulk soil sampling for laboratory analyses
and data validation. This paradigm is
believed to be flawed by some and in need of
change (e.g., 63,64). Questions can be raised
regarding the reasonableness of the current
practice of collecting a 1 to 5 g subsample
from a discrete location, analyzing it off-site
for a suite of VOCs of widely different
properties, scrutinizing the data point to
determine its "quality", and using only the
"quality" data for making inferences about
large soil regions (e.g., 50 to 100 m3 or
more).
Measurement of soil VOCs often involves
quantitation of a large number of organic
compounds with widely differing properties
(see Table 3). The basis for this is not clear
and quantifying a lengthy list of compounds
can compromise effective measurement of the
most prevalent and important ones. Evidence
is growing that quantification of a selected
number of compounds can yield adequate
information about the risk posed by a site and
the need for action (58).
It may be appropriate to reconsider and refine
the definition and categorization of VOCs.
The current categorization of VOCs was
developed based on analytical considerations.
Contaminant properties and sampling
considerations suggest that multiple
categories of VOCs may be appropriate. This
categorization should be based on the
environmental behavior of each soil VOC as
well as its environmental and public health
significance. For example, trichloroethylene
(TCE) would likely be grouped in a separate
category from ethylbenzene, based on TCE's
higher mobility, persistence, and adverse
health effects. Such a re-categorization
would be conducive to field screening and
onsite analytical methods, since it would
facilitate development and use of methods
targeted at one or a few analytes.
When making soil VOC measurements at a
given site, there is always need to define
boundaries for decision support zones. For
example, boundaries can be used to separate
clearly contaminated areas from clearly clean
areas. The use of diagnostic tools, like in situ
and ground surface soil vapor surveys,
represent a reasonable approach to boundary
definition. These techniques provide for
identification and cursory evaluation of areas
of potential contamination, but are limited for
quantitation of total soil VOCs (4). While
some argue for the quantitative and definitive
use of soil gas surveys in lieu of bulk soil
sampling and analysis, evidence supporting
this application has not been generated.
Sample acquisition from surface and near-
surface soil regions is normally done with
hand-held sampling tools and utensils (e.g.,
shovels and hand-augers, sampling spoons
and spatulas) (43). Sample acquisition at
depth (e.g., > 2 m) is often accomplished
using a backhoe or drilling equipment. Once
the bulk sample is acquired from the
subsurface, it is either containerized in the
sampling device (e.g., sleeve within a split-
barrel sampler) or subsampled and then
containerized in a relatively small vial or jar
(e.g., 40-mL glass vial) (43,76).
14
-------
100m2
Split spoon Field sample Sample analysis
sampler (0.10kg) (0.005kg)
Contaminated
soil zone
(2 x 10s kg)
_J
0.000002%
Fig. 4. Representation of a current paradigm for soil VOC measurement and interpretation (64).
The impact of sample acquisition on the
concentrations and phase distribution of
VOCs is not well understood. A number of
investigators have described the impact of
subsampling on true soil VOC
concentrations. Losses of up to 90% or more
have been recorded (30,43,62 - 65). Given
these observations, there is concern that the
sample acquisition process (e.g., coring) may
alter the distribution of VOCs in a decision
support unit. Minimizing disturbance of the
subsurface should minimize acquisition-
induced changes in VOC concentrations and
distributions.
Hydraulic-powered probes (e.g., cone
penetrometers) are new methods for sampling
the subsurface in a less disruptive manner'(5,
73,74). These commercially available pieces
of equipment are being increasingly utilized
to acquire discrete samples from depths up to
30 m or more. The performance of these
probe techniques is highly dependent on the
nature of the subsurface materials (e.g.,
sand, clay, gravel, boulders). In general,
these sampling techniques facilitate collection
of samples more rapidly, at lower cost, and
with less disruption. The addition of sensors
to the probe devices will enable the collection
of real-time information regarding VOCs in
the subsurface.
Once the bulk sample is acquired, one or
more subsamples are normally collected and
containerized. These samples are then
subjected to on-site analyses by qualitative or
quantitative methods (13, 26, 30, 31,42,46, 54,
58, 69,70,74,79). In many cases, samples are
preserved for holding prior to off-site
analyses which typically don't occur until
near the end of the 40CFR-mandated 14-day
holding time (76).
Questions were raised at the Symposium
regarding the changes in soil VOCs caused
by sample collection and handling. Research
conducted during the past five years has
consistently demonstrated that conventional
15
-------
practices for sample collection, container-
ization, and pre-analytical handling can result
in significant losses of VOCs (i.e., 90% or
more) (Fig. 5-9) (3,30,35,37,43,47, 51,62 -
65,67). The rate and extent of change varies
with VOC and soil matrix properties, with
seemingly higher rates of change with the
more volatile compounds. While the
mechanisms of change are not clearly
understood, a major cause is speculated to be
volatilization losses of analyte as a result of
disruption during sample collection, storage,
and laboratory subsampling.
Recent research and practice have revealed
alternative methods which can improve VOC
measurement accuracy by an order of
magnitude or more for the more volatile/low
solubility compounds (e.g., TCE) (43,51,65,.
73,75). Selected methods are highlighted
below.
VOCs (ug/g)
20-f
Method
U-TG-LH-4M
U-TG-LH-4
D-TG-LH-4
U-TG-HH-4
,__,___,_ D-PB-LH-4
O ' < ' < ' til ' _i ' CQ '
Compound
Fig. 5. VOC concentrations in samples of
sandy soil as affected by sample collection
and handling methods (65). (Note: Method
attributes: D = disturbed soil; U = undisturbed soil;
PB = plastic bag; TG = Teflon-sealed glass; LH =
low container headspace; HH = high container
headspace; 4 = 4°C holding; 4M = methanol
immersion at 4°C)
10*
.10'
iff
1/1
1/10 _
I il.l.l.l /\ , IJ.lJ I ,1,1,1,1 I ,1,1,1.1 I i 1.1,
1Q-3 10~* 10"1 10° 101 102
TCE (ng/g) ({standard protocol)
Fig. 6. TCE concentrations measured by
purge-and-trap GC/MS in collocated field
samples as collected by standard versus
modified methods (30, 31). (Note: Standard =
packing of a vial and lab subsampling; modified =
micro-core subsampling and methanol immersion.
LDE = limited disruption extraction)
One method involves collection of largely
undisturbed soil cores in sleeve-lined, split-
barrel samplers (2). The relatively
undisturbed soil cores are sealed within the
sleeves onsite and then transported to a
laboratory for controlled subsampling and
transfer to an analysis vessel. This method
eliminates one subsampling step (i.e., field
subsampling) and maintains an intact soil
volume until analysis is imminent at which
time a 1 to 5 g subsample is taken. This
approach, however, requires shipment of
larger quantities of material, subsampling by
someone unfamiliar with the site, and a small
subsample (i.e., 1 to 5 g) is still analyzed.
Another method involves onsite subsampling
with a micro-coring device to minimize soil
disturbance, a known cause of VOC loss
(Fig. 5 - 6). The soil from the micro-cores
16
-------
(e.g., 3 to 10 mL) can be extruded directly
into a 40-mL glass vial designed for analysis
without further soil sample transfers.
Analyses can be done by headspace
techniques (30,31,46,74) or by direct
connection to a purge-and-trap instrument
(64). This approach eliminates laboratory
subsampling, maintains low detection limits,
and does not requiring field handling of
chemicals. However, the sample volume
analyzed is quite small (1 to 5 g) and
compositing of soil samples is precluded.
Yet another method involves immediate
onsite immersion of a soil sample in an
organic solvent (e.g. methanol or a methanol
9000
8000
7000
5000
4000
3000
2000
1000
Conv. RFI
Mod. Purge &
Trap
Infield
Immersion in
MeOH
— o — Headspace
GC
80
70
UJ
600
so a
CO
40 §
o>
8
30 &
20 1
co
10
J- CM CO 1- CM
m m m m CD
Boring location - depth (ft)
Fig. 7. VOC concentrations in collocated
field samples from a silt and clay deposit as a
function of sample collection and handling
methods (63). (Note: Principal VOCs = TCE and
methylene chloride. RFI = conventional RCRA
packed vial and lab subsampling; Mod. Purge &
Trap = micro-core subsampling and on-site transfer to
a purge vessel; Infield immersion in methanol =
micro-core subsampling and on-site transfer to a
sample vial containing methanol; and Headspace GC
= micro-core subsampling and on-site transfer to a
sample vial containing distilled water. Analyses by
GC/MS except the Headspace analysis done by GC.)
solution) contained in a Teflon-sealed glass
vial or jar (Fig. 5 -7) (2,65,75). The ,
methanol acts to inhibit volatilization and
biodegradation while enhancing extraction
efficiency. This approach has the advantage
of increasing the sample size analyzed
(thereby attenuating short-range spatial
variability) and also enables sample
compositing. However, the methanol
addition can increase detection limits by a
factor of 10 to 100 and requires field
hamdling and transportation of potentially
hazardous chemicals. An alternative solvent
(e.g., acidified water) could mitigate this
problem.
Minimizing pre-analytical holding time and
variability of conditions is critical to help
reduce measurement error (35, 37,47). Soil
samples must either be analyzed upon
collection (e.g., field laboratory) or more
rigorously preserved than that provided by
simple 4°C refrigeration (e.g., infield solvent
immersion or closed-vial,) (Fig. 8 - 9).
Improved and expanded use of onsite
analytical instruments and techniques has
been demonstrated to provide VOC
quantisation equivalent to standard fixed-base
laboratory methods (Fig. 10) (30,31,46).
Sample analysis techniques are emerging that
focus on robust methodologies that provide
reasonable accuracy and precision for soil
VOCs. These are in contrast to methods that
enable ever lower detection limits.
Simplified, but effective, field instruments
arid procedures are rapidly becoming
available (1, 4, 17, 26, 31, 46, 58, 59, 60, 70).
Continued development and standardization
of field instruments and methods was deemed
necessary to stimulate their widespread and
appropriate use.
Sequential analysis of samples has been
demonstrated as a cost-effective strategy for
measuring contamination in ground water and
drinking water matrices (58). This approach
relies on compositing, a sampling strategy
that has not been commonly employed with
soil VOCs due to concerns over compound
losses and detection limit increases. While
composited samples seemingly could be
collected using methanol solutions, this
method has not been fully developed or tested
yet (63).
17
-------
10 100
Pre-analytical holding time (days)
10 100
Pre-analytical holding time (days)
0
vv
/N
D
+ 4'C
-20'C
-70'C
10 100
Pre-analytical holding time (days)
Fig. 8. Changes in concentrations of TCE in different soil media as affected by storage
temperature and holding time (after 35,47).
Soil VOC data vary widely in space and time;
an accurate measure at one location and time
may provide only limited insight into
concentrations at an adjacent location or time.
Soil VOC data are log-normally distributed
and it may be reasonable to reduce
expectations for measurement accuracy in
discrete samples to account for this fact. It
could be argued that soil VOCs should be
assessed on a log-scale in much the same
way soil bacteria or soil pH are.
7. DATA INTERPRETATION
Data assessment and interpretation must be
done carefully and include review of not only
sample collection, handling, and analysis
procedures, but also information about the
physical conditions at the site, source of
contamination and rate of release, and
exposure pathways. VOC measurements
made years ago are probably more suspect
than recent data due to recent improvements
in practices.
The current emphasis of data validation is
primarily on method adherence and does not
adequately address sample/analyte-specific
variability. For example, quality control
acceptance limits are set to correspond to
generally achievable windows by a
reasonable laboratory under normal operation
(e.g., surrogate, matrix spike, and matrix
spike duplicate recoveries). In addition,
laboratory analysis is the only component of
the whole range of error sources that is
considered. Depending on the type of data
and the depth of the assessment, costs for
validation can range from three to ten times
the analytical costs. These extremely high
costs and the inadequacy of current practices
make the development and implementation of
an effective data interpretation process a high
priority need. Both improving the quality
and changing the perspective of "data
18
-------
200
150 r^
100
CO
4'C
A Dry Ice
o Methanol
0
14
Pre-analytical holding time (daysf
Fig. 9. Average changes in gasoline concentrations in fine-grained sand as a function of
preservation methods (after 37).
validation" were ultimate goals this
Symposium was directed to meeting.
Alternatives to current data validation
practices are being conceived and evaluated.
Examples include the use of performance
evaluation materials (42) and laboratory splits
employing referee laboratories (39).
Interpretation must reconcile and integrate the
various elements of a soil VOC data set (e.g.,
field screening, on-site lab analysis, off-site
lab analysis, meteorological data, etc.). The
emphasis on the analytical portion of the
measurement process has inappropriately
focused on discrete values rather than on
comprehensive data sets and information
packages. The ultimate data collection goal is
an appropriate decision, not the perception of
highly documented laboratory results.
Alternatives to current data validation
practices, and efforts to develop and
implement these processes, are advocated to
provide optimized quality assurance in a more
time and cost efficient manner.
Detection limits and their impact on sample
analysis and interpretation are significant.
There appears to be an implicit assumption
made that lower detection limits are always
better. Drinking water maximum
contaminant levels (MCL's) have dictated
low detection limits in ground water samples
and may have led to a perceived need for
similar low limits in soil. However,
lowering detection limits may have adverse
consequences. For example, field portable
instruments may provide accurate, timely,
and cost-efficient analyses, but their use may
be limited because they are unable to reach a
low enough detection limit. GC's with
appropriate detectors are emerging that can be
used in the field and achieve equal or lower
detection limits than laboratory GC/MS's. In
many applications, however, achieving lower
detection limits may require more
sophisticated off-site laboratory equipment.
Due to the greater time and higher cost of
these off-site analyses, fewer samples may be
collected. As a result, spatial knowledge may
be sacrificed and decision-making impaired.
19
-------
10J =
i-l ' |'I'll I ' I MM' I ' I'I'M I TIT I ' I'CE
^* i i I -
10"3 10~2 • 10"1 10° 101 102
TOE (iig/g) (PT/GC/MS)
lack of spatial information provided in a
limited data set (Fig. 11). A most serious
short-coming within the current process of
characterizing subsurface regions for VOCs
may be the limited number of samples often
collected from which inferences are made
(e.g., one, 5-cm3 sample per 50 m3 of soil
region). While often based on justifiable
constraints, a limited number of samples can
leave great uncertainty in data interpretation,
even if analyses of the discrete samples were
accurate and precise. The unique properties
of VOCs in a soil system may complicate this
problem (e.g., multiphase behavior and
dynamic equilibrium).
A variety of 3-dimensional visualization tools
are becoming available to graphically
communicate information about subsurface
regions. Application to soil VOCs has been
done in several cases (46,52). While these
visualization tools offer great benefit, they
rely on spatial continuity of the dataset and
relatively intense sampling densities.
Fig. 10. Concentrations of TCE in soil as
determined by aqueous extraction
headspace/gas chromatography (HS/GC)
versus purge-and-trap gas chromatography/
mass spectrometry (PT/GC/MS) per EPA
SW-846, Method 8240 (30,31).
Another issue related to detection limits, is'
the treatment of data near or below the
detection limit. This subject was touched on
during the Symposium, but not fully
resolved. There is a growing body of work
on the subject and it is mentioned here only
as an issue to be dealt with.
Spatially and temporally disparate data can be
analyzed using a variety of statistical tools
(21,28,52). Spatial correlations and
geostatistical techniques enable regions of
interest to be characterized with some
measure of uncertainty. While different
statistical tools can provide different results,
most important to the successful application
of the tool is having an adequate spatial
dataset. No statistical, tool will overcome the
8. REGULATORY FRAMEWORK
Several key questions were raised and
discussed regarding institutional and
regulatory issues. There appeared to be some
confusion as to what flexibility is available to
those designing and implementing sampling
and analysis plans with regard to VOC
measurement. For example, there is a
perception that SW-846 methods are
mandatory and only acceptable as written in a
promulgated version. However, in only a
limited set of specific cases is use of SW-846
required by Federal regulation. SW-846 was
developed as a guidance document setting
forth acceptable but not required methods. It
seems that many methods were originally
developed using the best available
information at the time, even though it may
have been somewhat limited (41). Rather than
serving as guidance with provisions for
modification and change, many methods have
been "codified" and mandated, with
modification prohibited. This has evolved
from an interest in using standard methods,
which has in turn resulted in the simple
adoption of guidance methods as standards.
20
-------
1000000
100000 r
D)
10
6
O Measured Value
—-—— Average Predicted
Value
"•— ~ — Upper Bound
~~ ~ — Lower Bound
Soil sample (sorted by increasing predicted value)
a . - .
Fig. 11. Measured VOC concentrations for a sub-region of a contaminated site compared to the
predicted concentrations based on a 3-dimensional kriging model for the entire site (52).
For example, a number of States have
adopted SW-846 methods as mandatory
standard methods.
Sampling and analysis plans are written to
ensure quality control and legal defensibility
of the data. There is a desire to use "standard
methods" rather than best practices which are
based on recent research and experience. As
a result of this situation, there is great inertia
to maintain the status quo and the so-called
standard methods, even when the evidence
dictates change.
Efforts have been made to "standardize"
methods based on the results of recent
research and practice. For example, ASTM
adopted method D 4547, "Standard Practice
for Sampling Waste and Soils for Volatile
Organics" in August 1991 (2,72). This
method incorporates new knowledge
regarding the adverse effects of sample
disruption and holding in small containers
without preservatives. The method
prescribes collection of samples in. metal
rings (e.g., sleeves inserted in the sampling
barrel of a split-spoon sampler, D 3550) or
subsampling in the field using coring
cylinders. For field subsamples,
containerization is described for either ajar
containing methanol, or a dry container with
an adapter for direct connection to an
analytical instrument (72).
States are also promulgating standardized
methods based on new research. For
example, the state of Wisconsin now requires
the use of infield immersion in methanol for
samples contaminated with petroleum
hydrocarbons.
There is also continued work within EPA.
Several modifications to current analytical
methods are planned for the Third update of
SW-846 (41). One of the methods is
specifically written for VOCs in solid
21
-------
matrices. This method prescribes an
automated purge-and -trap system which
agitates the sample within the original
collection vessel during a 40°C purge step
(new SW-846 method 5035). This method
enhances VOC preservation (due to
minimizing sample disruption and handling)
and increases recovery efficiency due to the
agitation.
Widespread use of new methods by
practicing professionals requires their
adoption and approval for use by regulating
agencies. This adoption of methods by state
or Federal agencies often hinges on activities
by other standards-setting groups, like
ASTM or groups within EPA or DOE. While
current methods may.be judged deficient in
some respects, changes usually can be made
only after extensive methods development
and testing. To some extent this is justified,
since adequate information is required so a
deficient method is not replaced by another
method which has different but equally
detrimental deficiencies. An example for soil
VOCs could include a new method of
containerizing and preserving a sample that
provides dramatically improved VOC stability
but causes major problems with accurate and
precise analysis. This example illustrates one
of the difficulties in development and
adoption of new soil VOC methods. That is,
methods are typically for individual
fragments of the measurement process (e.g.,
sample collection or analysis). Yet
improving one fragment of the process may
have little positive, and perhaps a negative
impact on the overall process.
Advancements will continue to occur and
improvements will be made in current
practices on a local and national level.
However, to facilitate more timely changes
on a widespread basis, the requirements and
process for change must be defined. A •
strategy or protocol should be adopted and
widely disseminated that clearly describes the
requirements for deviation from purported
standard methods, either on a site specific or
general application basis.
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January 12-14, 1993. Las Vegas, NV.
Environmental Monitoring Systems
Laboratory, Las Vegas, NV.
89. van Ee, J.J., Blume, L.J. and Starks,
T.H. 1990. A rationale for the
assessment of errors in the sampling of
soils. EPA/600/4-90/013, U.S. EPA
Environmental Monitoring Systems
Laboratory, Las Vegas, NV.
90. Verschueren, K. 1983. Handbook of
Environmental Data on Organic
Chemicals, Van Nostrand Reinhold
Company, New York, NY (2nd
Edition).
26
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APPENDIX A: SYMPOSIUM PROGRAM
Day 1 - Tuesday, January 12, 1993
Session 1: Opening Session
Session Chairs: Bob Siegrist, Oak Ridge National Laboratory
Jeff van Ee, U.S. Environmental Protection Agency
8:30 Welcome and Introduction
Wayne Marchant, Director, U.S. EPA Environmental Monitoring Systems Laboratory, Las Vegas, NV
8:40 Symposium Organization and Purpose
Bob Siegrist, Oak Ridge National Laboratory
Jeff van Ee, U.S. EPA Environmental Monitoring Systems Lab
9:00 Keynote Remarks
Dave Bennett, Chief, Toxics Integration Branch, Hazardous Sites Evaluation Branch, U.S. EPA Office of
Emergency and Remedial Response
Joan Fisk, Chairperson, Interagency Steering Committee for Quality Assurance for Environmental
Measurements, Los Alamos National Laboratory - on Intergovernmental Personnel Act assignment
from U.S. EPA Office of Solid Waste and Emergency Response
Session 2: VOC Measurement Needs, Issues, and Concerns
Session Chairs: Jeff van Ee, U.S. Environmental Protection Agency
Pat Eagan, University of Wisconsin-Madison
9:30 VOC measurement in soils: the nature and validity of the process
Bob Siegrist, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN
10:00 Effect of VOC measurement uncertainty on the risk assessment process
Jeff Wong, Office of the Science Advisor, Toxics Substances Control, California EPA, Sacramento, CA
10:50 Panel Discussion and Open Microphone
Diane Easley, Environmental Scientist, U.S. EPA Region 7, Kansas City, KS
Dan Stralka, Toxics Integration Coordinator, Region 9, U.S. EPA
Barry Lesnik, U.S. EPA Office of Solid Waste, Washington, DC
Charles Van Sciver, Chief, Environmental Measurements Section, Department of Environmental Protection,
Trenton, NJ
Allen W. Verstuyft, Chevron Research and Technology Company, Richmond, CA
David Lincoln, Director of Risk Assessment, CH2M-Hill, Bellevue, WA
Ely Triegel, President, Triegel & Associates, Inc., Pittsburgh, PA
James Bentley, Vice President, Enseco Laboratories, Sacramento, CA
Al Tardiff, Program Manager, DOE Office of Technology Development, Washington, DC
Session 3: Soil VOC Measurements and Decision Making
Session Chairs: RuthBleyler, U.S. Environmental Protection Agency
Duane Geuder, U.S. Environmental Protection Agency
Measurement needs and uncertainty in the risk assessment process
David Lincoln, CH2M-HU1, Bellevue, WA f
Processes controlling the transport and fate ofVOCs in soils
Neil Hutzler, Michigan Technological University, Houghton, MI
Soil sampling strategies and the decision making process
Evan Englund, U.S. EPA Environmental Monitoring Systems Laboratory, Las Vegas, NV
Data quality objectives and statistical treatment of soil VOC data
Alfred Haeberer, Quality Assurance Management Staff, U.S. EPA Office of Research and Development,
Washington, DC
Sampling and analyses for soil VOCs
Michael Barcelona, Western Michigan University, Kalamazoo, MI
Field screening and soil gas measurement techniques for VOCs
Thomas Spittler, Region I Laboratory, U.S. Environmental Protection Agency, Lexington, MA
Special Interest Group Sessions (Concurrent)
1. Facilitator = Ruth Bleyler and Duane Geuder
2. Facilitator = Dave Bottrell and Martin Stutz
3. Facilitator = Dean Neptune and Joan Fisk
5:30 Poster Session
1:00
1:30
2:00
2:30
3:30
4:00
4:30
27
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Day 2 - Wednesday, January 13, 1993
Session 4: Soil VOC Behavior and Measurement Implications
Session Chairs: Bruce Bauman, American Petroleum Institute
Martin Stutz, U.S. Army Environmental Center
8:00 Review of VOC sorption behavior in soils
Marti Minnich, Lockheed Environmental Systems and Technology, Las Vegas, Nevada
8:20 The persistence of several volatile organic compounds in a low organic carbon calcareous soil from southern
Nevada
Spencer Steinberg* and David Kreamer, *Department of Chemistry, University of Nevada, Las Vegas, NV
8:40 Standard model for volatilization of chemicals from soil at Superfund sites
Janine Dinan, U.S. EPA Office of Emergency and Remedial Response, Washington, DC
9:00 VOC contamination in ground water: sources of variability and comparison of soil, well and hydropunch results
Michael Barcelona*, Allan Wehrmann, Jane Denne, and Dannette Shaw, *Western Michigan University,
Kalamazoo, MI
9:20 Statistical simulation and 3-dimensional visualization for analysis and interpretation of soil VOC datasets
Toby Mitchell*, Olivia West, R.L. Siegrist, *Eng. Physics & Math Division, Oak Ridge National
Laboratory, Oak Ridge, TN
9:40 Open microphone
Session 5: Sample Collection and Handling for Soil VOCs
Session Chair: Dave Bottrell, U.S. Department of Energy
10:20 Comparison of collection and handling practices for the analysis of volatile organic compounds in soils
Alan Hewitt, U.S. Army Cold Regions Research Laboratory, Hanover, NH
10:40 Experimental determination of maximum pre-analytical holding times for volatile organics in selected soils
Roger Jenkins, Chuck Bayne, Mike Maskarinec, L.H. Johnson, S.K. Holladay, and B.A. Tomkins, Oak
Ridge National Laboratory, Oak Ridge, TN
11:00 Evaluation of sample holding times and preservation methods for gasoline in fine-grained sand
Paul King, P&D Environmental, Oakland, CA
11:20 Development of an ASTM standard for sampling soils for VOCs
Ely Triegle, Triegle & Associates, Inc., Pittsburgh, PA
11:40 Open Microphone
Session 6: Measurements of Soil VOCs by In Situ & Onsite Techniques
Session Chair: Roger Jenkins, Oak Ridge National Laboratory
1:00 Soils, synthetics, and screening: may the odds be with you
R. Rajagopal, University of Iowa, Iowa City, LA
1:30 Geoprobe soil sampling and field VOC analyses by gas chromatography
Hunt Chapman and Jeff Tuttle, Envirosurv, Inc., Arlington, VA
1:50 An evaluation of four field screening techniques for measurement ofBETX
E.N. Amick and J.E. Pollard, Lockheed Engineering & Sciences Co., Las Vegas, NV
2:10 Application of field VOC data in quantitative risk assessment at CERCLA sites
Ruth Kramel and Anthony Armstrong, Health and Safety Research Division, Oak Ridge National
Laboratory, Oak Ridge, TN
2:30 Site investigations: the role of field screening & analytical tools
Fred Cornell, Environmental Management, Inc., Princeton, NJ
2:50 Advances in on site and in situ VOC measurement techniques
Eric Koglin, U.S. EPA Environmental Monitoring Systems Laboratory, Las Vegas, NV
Session?: Laboratory Sample Analyses for Soil VOCs
Session Chair: Barry Lesnik, U.S. Environmental Protection Agency
3:30 Laboratory analyses and quality assurance for soil VOCs
Jim Bentley, Enseco Labs, Sacramento, CA
3:50 Interlaboratory study of analytical methods for petroleum hydrocarbons
Roger Claff*, Dianna Kocurek, Jeff Lowry and Jerry Parr, *American Petroleum Institute, Washington, DC
4:10 Modifications to EPA procedures for soil VOC analyses
Barry Lesnik, U.S. EPA Office of Solid Waste, Washington, DC
4:30 Open microphone
28
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5:00 Special Interest Group Sessions (Concurrent)
1. Facilitator = Ruth Bleyler and Duane Geuder
2. Facilitator = Dave Bottrell and Martin Stutz
3. Facilitator = Dean Neptune and Joan Fisk , ,
5:30 Poster session , . . .
Day 3 - Thursday, January 14,1993
Session 8: State of the Art and Research Needs ^
Session Chairs: Bob Siegrist, Oak Ridge National Laboratory
Jeff van Ee, U.S. Environmental Protection Agency
8:00 Special Interest Group Session Presentations
1. Facilitator = Ruth Bleyler and Duane Geuder
2. Facilitator = Dave Bottrell and Martin Stutz
3. Facilitator = Dean Neptune and Joan Fisk
10:00 Panel Commentary
Diane Easley, Environmental Scientist, U.S. EPA Region 7, Kansas City, KS
Dan Stralka, Toxics Integration Coordinator, Region 9, U.S. EPA
Barry Lesnik, U.S. EPA Office of Solid Waste, Cincinnati, OH
Charles Van Stiver, Chief, Environmental Measurements Section, New Jersey Department of
Environmental Protection, Trenton, NJ
Allen W. Verstuyft, Chevron Research and Technology Company, Richmond, CA
David Lincoln, Director of Risk Assessment, CH2M-Hill, Bellevue, WA
Ely Triegel, President, Triegel & Associates, Inc., Pittsburgh, PA
James Bentley, Vice President, Enseco Laboratories, Sacramento, CA
Al Tardiff, Program Manager, DOE Office of Technology Development, Washington, DC
11:30 Open Microphone
12:00 Closing Remarks and Symposium Adjournment
Poster Session —
Purge-and-trap GC/MS method modifications
Steve Ward, Harry Reid Center for Environ. Studies, University of Nevada, Las Vegas, NV
Slow desorption dynamics for volatile organic compounds from five ion-exchanged smectites
Jerry Fairly* and Spencer Steinberg, *Department of Geoscience and the Water Resources Management
Program, University of Nevada, Las Vegas, NV
Experimental determination ofnon steady-state diffusion of o-xylene from a sandy soil
B. Lindhardt and T.H. Christiansen, Technical University of Denmark, Department of Environmental
Engineering, Lyngby, Denmark
Performance of a new soil sampling tool for use with methanol preservation of samples containing volatile organic
compounds
David E. Turriff, En Chem, Inc., 1795 Industrial Drive, Green Bay, WI
Preanalytical holding times: advanced data treatment
Chuck Bayne*, Denise Schmoyer, Roger Jenkins, "Computing and Telecommunications Division, Oak Ridge
National Laboratory, Oak Ridge, TN
Active soil gas sampling - collection by air withdrawal
Samuel Johnson and T.V. Prasael, The Advent Group, Inc., Brentwood, TN
Field identification and quantitation of volatile organics in soils utilizing fourier transform infrared (FTIR)
spectroscopy
J. Demirgian*, M. Clapper-Gowdy, G. Robitaille, *Analytical Chemistry Division, Argonne National
Laboratory, Argonne, JJL
The inadequacy of commonly used risk assessment guidance for determining whether solvent-contaminated soils can
affect ground water at arid sites
Nic Korte*, Pete Kearl, T.A. Gleason, and J.S. Beale, *Environmental Sciences Division, Oak Ridge National
Laboratory, Grand Junction, CO
Referee analyses - a better approach than data validation
Nic Korte* and David Brown, Environmental Sciences Division, Oak Ridge National Laboratory, Grand
Junction, CO
29
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Vapor fortification: a method to prepare quality assurance soils for the analysis of volatile organic compounds
Allan Hewitt, U.S. Army Cold Regions Research and Engineering Lab, Hanover, NH
Field observations of variability of soil gas measurements
Jon Fancher, Westinghouse Hanford Co., Richland, WA
Estimation of potential VOC emissions during trial excavation activities via flux chamber andfourier transform
infrared open path transform
Michelle Simon, U.S. EPA Risk Reduction Eng. Lab, Cincinnati, OH
The effect of barometric pumping on the migration of volatile organic compounds from the vadose zone into the
atmosphere
Robert Pirkle*, Douglas Wyatt, Van Price, and Brian Looney, *Microseeps, Pittsburgh, PA
Use of risk assessment ground water model in installation restoration program site decisions
David Goldblum*, John Clegg, John D. Erving, Sverdrup Environmental, San Antonio, TX
A fiber optic chemical sensor for the measurement ofTCE
Marcus Butler, Stanley Klainer*, Kisholov Gosvami and Jonahtan Tussey, *FiberChem, Inc., Las Vegas, NV
Biodegradation of high concentrations ofTCE and effects on aquifer permeability
Martin A. Rowland, New Orleans, LA
Field analysis of VOC's by photoacoustic detection
John McClelland, R.W. Jones, and S. Ochiai, Ames Laboratory, Iowa State University, Ames, IA
Evaluation ofheadspace method for volatile constituents in soils and sediments
Brian Looney, C.A. Eddy, W.R. Sims, Westinghouse Savannah River Company, Aiken, SC
On-site analysis of VOCs in soils by transportable GC/MS
Jeff Christensen and Dave Quinn, Viking Instruments, Reston, VA
Measuring the flux of chlorinated, volatile organic compounds from the soil surface
Paul Daley* and Stan Martins, *Environmental Restoration Division, Lawrence Livermore National
Laboratory, Livermore, CA
30
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APPENDIX B: LIST OF ATTENDEES
Attendee
Affiliation
Location
Bruce Bauman
Ruth Bleyler
David Bqttrell
Patrick Eagan
Joan F. Fisk
Duane Geuder
Roger A. Jenkins
Eric Koglin
Mike Maskarinec
Robert L. Siegrist
Martin H. Stutz
Jeff van Ee
Joseph S. Arena
J.W. Atwater
Jim Barnaby
Susan W. Bass
Charles. K. Bayne
Dan Bergman
Bernie B. Bernard
Charles Bidondo
Peter Biltoft
Gary Bloom
Celeste Bonnecaze
Randy Borne
Ralph Boyajian
Thomas Brennan
Douglas Brune
Tim Buck
ChuckBulik
Thomas J. Buntin
Larry C. Butler
Anton Camarota
Kenyon C. Carlson
Joel Carson
Earl Cassidy
Hunt Chapman
David R. Clark
Fred W. Cornell
Joe D'Lugosz
Doug Davenport
Marcia C. Davies
Edward DeNoyelles
Jane Denne
Paul Deutsch
Roger Dewey
Robert S. Dickerson
Frances Dooley
Jack L. Downie
Jamie Drakey
Bart Draper
Diane Easley
Randy Eatherton
American Petroleum Institute
U.S. Environmental Protection Agency
U.S. Department of Energy
University of Wisconsin
Los Alamos National Laboratory
U.S. Environmental Protection Agency
Oak Ridge National Laboratory
U.S. Environmental Protection Agency
Oak Ridge National Laboratory
Oak Ridge National Laboratory
U.S. Army Environmental Center
U.S. Environmental Protection Agency
U.S. Environmental Protection Agency
University of British Columbia
Analytical Technologies, Inc.
Compu-Chem Laboratories
Oak Ridge National Laboratory
Pyrite Cannon Group
O.I. Analytical
Shoshone Bannock Tribes
Lawrence Livermore National Lab
Martin Marietta Energy Systems
LA. Dept. of Environmental Quality
B.P. Oil
Boyajian and Ross, Inc.
Martin Marietta Energy Systems, Inc.
U.S. Environmental Protection Agency
Lake Superior Labs
Nevada Div. Environmental Protection
U.S. Environmental Protection Agency
U.S. Environmental Protection Agency
S.M. Stoller
Arizona State Lab
Sitex Environmental Inc.
U.S. Geological Survey
Envirosurv, Inc.
Westinghouse Savannah River Co.
Environmental Liability Management
U.S. Environmental Protection Agency
Martin Marietta Energy Systems, Inc.
U.S. Army Corps of Engineers
National Resources and Environ. Affairs
U.S. Environmental Protection Agency
Boyajian and Ross, Inc.
Ryan-Murphy, Inc.
Georgia Power Company
Bechtel Environmental Inc.
U.S. Environmental Protection Agency
U.S. Environmental Protection Agency
Bechtel Environmental Inc.
U.S. Environmental Protection Agency
Weyerhaeuser
Washington, D.C.
Washington, IXC.
Washington, D.C.
Madison, WI
Los Alamos, NM :
Washington, D.C.
Oak Ridge, TN
Las Vegas, NV
Oak Ridge, TN
Oak Ridge, TN
Aberdeen, MD '
Las Vegas, NV
Philadelphia, PA
Vancouver, BC
Fort Collins, CO
Res. Triangle Park, NC
Oak Ridge, TN
Riverside, CA
College Station, TX
Fort Hall, ID
Livermore, CA
Knoxville, TN
Baton Rouge, LA
Belle Chasse, LA
Fresno, CA
Oak Ridge, TN
Kansas City, KS
Duluth, MN
Carson City, NV
Philadelphia, PA
Las Vegas, NV
Boulder, CO
Phoenix, AZ
Salt Lake City, UT
Denver, CO
Fairfax, VA
Aiken, SC
Princeton, NJ
Las Vegas, NV
Piketon, OH
Omaha, NE
Twentynine Palms, CA
Las Vegas, NV
Fresno, CA .
Westminster, CO
Smyrna, GA
San Francisco, CA
Wheeling, WV
Kansas City, KS
San Francisco, CA
Kansas City, KS
Federal Way, WA
31
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Attendee
Affiliation
Location
Larry Eccles
E. L. Ekholm
MarkEklund
Jess S. Eldridge
William Englemann
Jeffrey G. Entin
Mitch Erickson
Jane Faria
Gary L. Fenwick
Mario Fernandez
Joseph Fernando
Richard Flotard
Vance Fong
Chris Frye
EdFuru
Richard Gammage
Steve Gardner
Richard L. Garnas
William E. Gawlik
Donald F. Gilmore
Robert Glowacky
David K. Goldblum
Don Gomsi
Iris Goodman
Chuck Graf
Michael J. Grant
Rod D. Grant
Daniel S. Granz
Russell W. Grimes
BradHahn
Kathleen Hall
Karen Hammertrom
Jon K. Hammock
Stephen Harden
Sara Harmon
Steve Harrar
Burt C. Harrison
Thomas Hauk
Tim Hawe
Robbie Hedeen
Robert Henckel
George K. Hess
Alan D. Hewitt
Judy Hey wood
Michael H. Hiatt
Sibyl Hinnant
Edwin D. Hogle
Judith Hohnholt
Mark Hollenbach
Neil J. Hutzler
Michael lanniello
J. Larry Jack
Kurt J. Jacobsen
Ralph Jennings
Fetter D. Jenssen
U.S. Environmental Protection Agency
Consulting Engineer
Park Environmental
3M
U.S. Environmental Protection Agency
Sadat Associates, Inc.
Argonne National Laboratory
Radian Company
Shoshone-Bannock Tribe
U.S. Geological Survey
Mitre Corporation
U.S. Environmental Protection Agency
U.S. Environmental Protection Agency
XTT Technologies
Park Environmental
Oak Ridge National Laboratory
U.S. Environmental Protection Agency
U.S. Environmental Protection Agency
Anacomp, Inc.
EMPE, Inc
Aqua Tech Environmental Labs
Consultant
San Bernadino Co. E H S
U.S. Environmental Protection Agency
Arizona Department of Environmental Health
Southern Pacific Lines
EG&G Idaho, Inc.
U.S. Environmental Protection Agency
U.S. Bureau of Reclamation
State of Alaska
Lockheed Environmental Systems & Tech.
U.S. Environmental Protection Agency
Consultant
U.S. Geological Survey
Oak Ridge National Laboratory
Aqua Tech Environmental Labs
U.S. Air Force
Martin Marietta Energy Systems, Inc.
U.S. Environmental Protection Agency
U.S. Environmental Protection Agency
Westinghouse Hanford Co.
U.S. Environmental Protection Agency
U.S. Army CRREL
Arizona Dept. of Environmental Quality
U.S. Environmental Protection Agency
U.S. Environmental Protection Agency
U.S. Environmental Protection Agency
U.S. Bureau of Reclamation
Chem-Nuclear Geotech
Michigan Technological University
General Electric
U.S. Environmental Protection Agency
Keil Environmental Engineering
Radian Corporation
Center for Soil and Environmental Research
Las Vegas, NV
Houston, TX
Anaheim, CA
St. Paul, MN
Las Vegas, NV
Princeton, NJ
Argonne, TL
Sacramento, CA
Fort Hall, ID
Tampa, FL
Brooks AFB, TX
Las Vegas, NV
Las Vegas, NV
Costa Mesa, CA
Anaheim, CA
Oak Ridge, TN
Las Vegas, NV
Las Vegas, NV
Sunnyvale, CA
Nashville, TN
Melmore, OH
San Antonio, TX
San Bernadino, CA
Las Vegas, NV
Phoenix, AZ
San Francisco, CA
Idaho Falls, ID
Lexington, MA
Sacramento, CA
Anchorage, AK
Las Vegas, NV
Washington, D.C.
Aiken, SC
Raleigh, NC
Oak Ridge, TN
Melmore, OH
San Antonio, TX
Piketon, OH
Las Vegas, NV
San Francisco, CA
Richland, WA
Kansas City, KS
Hanover, NH
Phoenix, AZ
Las Vegas, NV
Philadelphia, PA
Denver, CO
Denver, CO
Grand Junction, CO
Houghton, MI
Albany, NY
Las Vegas, NV
Waunakee, WI
Austin, TX
Aas, Norway
32
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Attendee
Affiliation
Location
William Jeong
Keith A. Johnson
Roger W. Jones
Greg A. Junk
David Kammerer
Krishan Kapur
Michele Kennard
Fred Kent
James M. Kiefer
Mark L. King
Paul King
Glenn Kistner
Christine Klopp
PatDuttKomor
Nic Korte
Dennis Korycinski
Pamela Kostle
Karen. Kotz ,
Gyula F. Kovach
Anna F. Krasko
Paul D. Kuhlmeier
Mark Kuzila
David C. Lanigan
Rod Larson
George H. Lee
Robert Lee
Chris Leibman
Angela Levert
BoLindhardt
Viorica Lopez-Avila
Lawrence Love, Jr.
Sandy Mapes
James Mason
Wayne Mattsfield
Aldo Mazzelo
Craig R. McCaffrey
Kelly McCarty
Timothy S. McCormick
Thomas Lee McGhee
Gene Meier
Martha Minnich
Dean Mireau
John Moore
Katherine Moore
Chris Morgante
Robert D. Morrison
Mary K. Mueller
Tom Neefe
Bruce Nelson
Dean Neptune
Pat Newby
Barbara Newman
John M. Nocerino
Robert J. Ostrowski
Enseco-CRL
Emcon Associates
Ames Laboratory - U.S. DOE
Ames Laboratory - U.S. DOE
Enseco-CRL
Bechtel Environmental Inc.
Arizona Department of Environmental Quality
Lockheed Environmental Systems & Technologies
U.S. Environmental Protection Agency
Enseco-CRL
P & D Environmental
U.S. Environmental Protection Agency
Wisconsin DNR
University of Wisconsin
Oak Ridge National Laboratory
U.S. Air Force
University of Iowa - -
Geo Engineers
National Institutes of Health
U.S. Environmental Protection Agency
Morrison-Knudsen Corporation
University of Nebraska
Battelle
U.S. Geological Survey
U.S. Air Force, Brooks AFB
Geo West Group, Inc.
Los Alamos National Laboratory
ERM-Southwest
Technical University of Denmark
Midwest Research Institute
FERMCO
ENSR Consulting & Engineering
Aqua Tech Environmental Labs
Barr Engineering Co.
U.S. Environmental Protection Agency
Agri-Diagnostics
U.S. Environmental Protection Agency
CH2M Hill
Texas A and I University
U.S. Environmental Protection Agency
Lockheed Environmental Systems & Technologies
Nevada Division of Environmental Protection
U.S. Environmental Protection Agency
U.S. Environmental Protection Agency
Tektronix, Inc.
R. Morrison and Associates
S.L.V. Analytical Services
Ryan-Murphy, Inc.
Geo Centers, Inc.
Neptune & Company
State of Montana Dept. of Health & Env. Sci.
U.S. Environmental Protection Agency
U.S. Environmental Protection Agency
National Institute of Health
Garden Grove, CA
Burbank, CA
Ames, IA
Ames, LA
Garden Grove, CA
Norwalk, CA
Phoenix, AZ
Las .Vegas, NV
Denver, CO
Garden Grove, CA
San Francisco, CA
San Francisco, CA
Madison, WI
Shoreview, MN
Grand Junction, CO
MacDill AFB, FL
Iowa City, LA
Redmond, WA
Bethesda,MD
Boston, MA
Boise, ID
Lincoln, Np .
Richland, WA
Cheyenne, WY
San Antonio, TX
Scottsdale, AZ
Los Alamos, NM
Houston, TX
Lynby, Denmark
Mountain View, CA
Cincinnati, OH
Anchorage, AK
Melmore, OH
Minneapolis, MN
Las Vegas, NV
Moorestown, NJ
San Francisco, CA
Belleville, WA
Kingsville, TX
Las Vegas, NV
Las Vegas, NV
Carson City, NV
Las Vegas, NV
San Francisco, CA
Beaverton, OR
Carpinteria, CA
Alamosa, CA
Westminster, CO
Newton Center, MA
Los Alamos, NM
Helena, MT
Boston, MA
Las Vegas, NV
Bethesda, MD
33
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Attendee
Affiliation
Location
Jerry L. Pan-
Kent Patrick-Riley
David A. Peterson
J.J. Pignatello
Bob J. Pirkle
Robyn Poole
David W. Poppler
Edward Poziomek
Lynne M. Preslo
Rus Purcell
Peter Quinlan
Dave Quinn
Werner Raab
Michael Ramirez
Karl W. Ratzlaff
William K. Reagen
Ileana Rhodes
Robert J. Rinne
James Rittenburg
Gary L. Robertson
John R. Rohde
Dennis Rolston
Charlita Rosal
Janice Rose
Emily Roth
Terry Roundtree
Marty Rowland
Greg Ruff
Robert Runyon
Nick Saines
Roseanne Sakamoto
Lora Scalise
John Schabrun
Denise Schmoyer
Susan C. Schock
Bill Seay
Kathy Setian
Dannette M. Shaw
Ron Sheeley
Kurt Slentz
James S. Smith
Steven N. Spearman
Thomas Spinier
Spencer Steinberg
Neal Stolpe
Dan Stralka
Lawrence W. Stratton
Chris Stubbs
Robert Sundberg
Thomas Taccone
Chi M. Tan
Jim Tarwater
John Tittefite
Karl Topper
Enseco
State of Alaska
U.S. Geological Survey
Connecticut Agri. Exp. Station
Microseeps
Shell Development Co.
L.A. County Public Works Geology
University of Las Vegas
ICF Kaiser Engineers
Kennedy/Jenks Consultants
Dudek and Associates, Inc.
Viking Instruments
Mitre Corporation
FERMCO
Sverdrup Environmental, Inc.
3M
Shell Development Co.
Trow Consulting Engineers Ltd.
Agri-Diagnostics Associates
U.S. Environmental Protection Agency
University of Nebraska
University of California
U.S. Environmental Protection Agency
U.S. Environmental Protection Agency
U.S. Environmental Protection Agency
U.S. Environmental Protection Agency
Rowland and Associates
Tekmar Company
U.S. Environmental Protection Agency
KMnfelder
U.S. Environmental Protection Agency
U.S. Environmental Protection Agency
Western Research Institute
Oak Ridge National Laboratory
U.S. Environmental Protection Agency
Nittany Geoscience
U.S. Environmental Protection Agency
Western Michigan University
Missouri DNR
Energy Laboratories, Inc.
Trillium, Inc.
National Park Service
U.S. Environmental Protection Agency
University of Nevada - Las Vegas
University of Nebraska
U.S. Environmental Protection Agency
U.S. Environmental Protection Agency
U.S. Environmental Protection Agency
Enseco
U.S. Environmental Protection Agency
U.S. Environmental Protection Agency
Ecology and Environment, Inc.
XTT Technologies
Mesa State College
Arvada, CO
Anchorage, AK
Cheyenne, WY
New Haven, CT
Pittsburgh, PA
Houston, TX
La Crescenta, CA
Las Vegas, NV
Rancho Cordova, CA
Irvine, CA
Encinitas, CA
Reston, CA
McLean, VA
Cincinnati, OH
San Antonio, TX
St. Paul, MN
Houston, TX
Thunder Bay, Ontario
Cinnaminson, NJ
Las Vegas, NV
Lincoln, NE
Davis, CA
Las Vegas, NV
Las Vegas, NV
San Francisco, CA
Chicago, IL
New Orleans, LA
Thousand Oaks, CA
Las Vegas, NV
Las Vegas, NV
San Francisco, CA
Las Vegas, NV
Laramie, WY
Oak Ridge, TN
Cincinnati, OH
State College, PA
San Francisco, CA
Kalamazoo, MI
Jefferson City, MO
Rapid City, SD
Coatesville, PA
Boulder City, NV
Lexington, MA
Las Vegas, NV
Lincoln, NE
San Francisco, CA
Denver, CO
San Francisco, CA
Garden Grove, CA
New York, NY
Richton Park, IL
Overland Park, KS
Costa Mesa, CA
Grand Junction, CO
34
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Attendee
Affiliation
Location
Phillip Toy
Faye Troisi
Bruce R. Tucker
Basil Tupyi
JeffTuttle
Chris Van Der Woerd
Charles Van Sciver
Katrina Varner
Al Verstuyst
Harold A. Vincent
Suzanne Volk
Dorothy Walker
Steve Ward
Randy Wheeler
Ralph White
Curtis Wilbur
Bill Wilder
Susan Willoughby
Matthew Wolfinger
Jeff Wong
John S. Zogorski
John Zwierzycki
Enseco - CRL
Arizona Dept. of Environmental Quality
Quadrel Services, Inc.
Morrison and Knudsen
Envirosurv, Inc.
Anacomp, Inc.
New Jersey Dept. of Envr. Protection
U.S. Environmental Protection Agency
Chevron
U.S. Environmental Protection Agency
Indiana Dept. of Environmental Management
U.S. Geological Survey
H. Reid Center for Environmental Studies
Kleinfelder, Inc.
U.S. Geological Survey
Lockheed
Martin Marietta Energy Systems, Inc.
PRC Environmental Management
Anacomp, Inc.
California Environmental Protection Agency
U.S. Geological Survey
URS Consultants
Garden Grove, CA
Phoenix, AZ
Ijamsville, MD
Boise, ID
Fairfax, VA
Hayward, CA
Trenton, NJ
Las Vegas, NV
Richmond, CA
Las Vegas, NV
Indianapolis, IN
Arvada, CO
Las Vegas, NV
Sacramento, CA
Arvada, CO
Sunnyvale, CA
Oak Ridge, TN
Rancho Cordova, CA
Sunnyvale, CA
Sacramento, CA
Rapid City, SD
San Francisco, CA
35
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APPENDIX C: DISCUSSION QUESTIONS FOR THE WORKING GROUPS
Questions were developed in three areas by the planning committee, including sampling and
analysis planning (denoted as "P"), sample collection, handling, and analysis (denoted as "H"),
and data assessment (denoted as "A"). These questions were provided to the Symposium
participants and used as a framework for discussion during the Symposium and the working group
sessions.
C.I Questions Regarding Sampling and Analysis Planning
Questions regarding sampling and analysis planning (denoted as "P") were framed around the
following: During up front planning for data collection of VOCs in soil, what considerations are
important to obtain the right kind of data for the various uses of that data, including risk
assessment, remedial action design and implementation, clean-up goal achievement, waste
management, and monitoring?
1. What is unique about measuring VOCs in soil that makes this Symposium important? Can we
use this measurement data as an indicator of other problems such as potential aquifer
contamination through use of a model? What exposure pathways are of greatest concern with
VOCs in soil (e.g., for risk assessment)?
2. Are there any situations where VOCs may present more of a problem than other contaminants
(e.g., sites with certain contamination release characteristics, physical conditions, or exposure
scenarios)?
3. What techniques will ensure collecting and measuring representative samples for various data
uses: (1) risk assessment, (2) remedial action design and implementation, (3) clean-up goal
achievement, (4) waste management, (5) monitoring?
4. What effect does spatial and temporal variation in phase distribution across a site have on
obtaining a representative set of samples? What technique can accurately describe and predict
the spatial distribution of VOCs across a site (e.g., kriging)?
5. Can existing fate and transport models accurately describe and predict the behavior of VOCs in
soil to account for all phases (e.g., non-aqueous, aqueous, vapor, sorbed)?
6. How can field analysis or screening be used to optimize the collection of VOC in soil data? Are
there any quantitative field analysis methods available that can be used for risk assessment and
other decision making? [also in "H"]
7. What additional information is needed to maximize the use of VOCs in soil data to allow more
informed decision making (e.g., site meteorology and geology, soil particle size distribution,
water content, pH, organic carbon, etc.)? [also in "H" and "A"]
8. Are performance evaluation materials to quantify sampling and analysis error necessary?
Appropriate? Feasible? Available? How should error be expressed? [also in "H"]
C.2 Questions Regarding Sample Collection, Handling, and Analysis
Questions regarding sample collection, handling, and analysis (denoted "H") were framed around
the following: How can the information necessary to support environmental decisions be most
efficiently produced; i.e., execution of the sampling and analysis plan such that it meets the user
36
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needs as determined by the data review process?
1. How should soil samples for VOC analyses be collected, handled, and prepared? Does sample
acquisition affect the integrity of the sample (e.g., probing versus drilling/tube sampling)? Are
cores encased in sleeves preferred over transfer to a sample container (e.g., 40-mL VGA vial)?
Are special preservation techniques required for soil samples which are to be held prior to
analysis (e.g., solvent immersion)? ......
2. Many alternatives to current technologies have been described and documented in the
presentations at the Symposium. What is preventing their acceptance and use?
3.
How can field analysis/screening be used to optimize collection efforts? Are there any
quantitative field methods appropriate to support environmental decisions (e.g., risk
assessment, waste management)?
4. One mechanism to foster acceptance of advances in technology is by designation of alternatives
to current practices during the planning process (e.g., effective use of field data). Is this
practical and is it done? How can it be encouraged?
5. What fraction of VOCs present in soil are measured by different analytical methods? Do
current analytical methods for VOCs in soil accurately characterize potential problem situations
(e.g., tightly sorbed VOCs, VOCs in soil matrix micropores, non-aqueous phase VOCs)?
6. What additional information is needed to maximize the use of VOC in soil data to allow more
informed decision making (e.g., site meteorology and geology, soil particle size distribution
water content, pH, organic carbon, etc.)? [also in "P" and "A"]
7. Are performance evaluation materials to quantify sampling and analysis error necessary?
Appropriate? Feasible? Available? How should error be expressed? [also in "P"]
8. Can samples for soil VOCs be composited? What are the advantages and limitations for risk
assessment, remedial action design, or waste management? What methods can be used to
create a valid composite?
C.3 Questions Regarding Data Assessment
Questions regarding data assessment (denoted as "A") were developed in the following framework-
How can the data assessment process for soil VOCs (herein, meaning the entire process including
review of the data for technical quality and integrity, assimilation with other needed data, statistical
analysis treatment of the data, and the determination that the data is suitable for the decision to be
made) and the communication of its product be improved to save time and resources, and provide
products for more efficient use by the users (e.g., risk assessors, engineers designing remedial
strategies, waste management personnel, etc.)?
1. How can the data assessment process be streamlined?
2. How can data collection and analyses results be best interpreted and communicated for more
efficient use for the various uses of the VOCs in soil data? What communication is needed for
(1) risk assessment, (2) remedial action design and implementation, (3) clean-up goal
achievement, (4) waste management, (5) monitoring?
3. How are data quality parameters (e.g., precision, accuracy, detection levels) best
defined/determined for VOCs in soil?
37
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4. How can field analytical data be assessed for adequate quality for various intended uses? -
e.g., placing of wells, identifying hot spots, risk assessment, performance verification? - or
when is it necessary to perform data assessment in real time on field analysis of VOCs in soils
[related to question 3 in "H" group]?
5. What additional information is needed to maximize the use of VOC in soil data to allow more
informed decision making (e.g., site meteorology and geology, soil morphology, water
content, pH, organic carbon, etc.)? [also in "P" and "A"]
6. How can performance evaluation materials be used to assess the quality of VOCs in soil data
and the appropriateness of the analytical method used? [related to question 7 in "H" group]?
7. How does a decision maker reconcile data sets comprised of different measurements (e.g., soil
gas results, on-site soil sample analyses, off-site laboratory analyses, etc.)? Should data
quality be viewed less on a discrete sample/analyte basis and more on a region of interest basis?
8. What statistical tools should be used for treatment of VOCs in soil data? Should the data be
analyzed after log transformation? Should the data be reported and decision making done on a
log-scale (likepH)? Other?
38
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APPENDIX D: DISCUSSIONS IN THE WORKING GROUP SESSIONS
Working group discussions were held at the end of the first and second day of the Symposium.
Symposium participants were free to participate in one of three groups, each led by two pre-
assigned facilitators. Participants could move from one group to another and were encouraged to
interact freely and openly regarding all relevant issues. In some cases, the facilitators within a
group set the focus for the group and only some issues were discussed in detail.
During each group session, remarks were recorded as they were made, using marking pens and
flip charts. While the facilitators were responsible for recording the information exchanged, it was
done m a fashion to avoid any censorship or bias in the reporting as given below. The information
presented and so recorded is provided below.
D.I Responses and Remarks of Working Group 1
Remarks made by participants involved in Working Group 1 discussions were recorded by the
facilitators, Ruth Bleyler and Duane Geuder. A summary of the key remarks is given below.
What is Unique About VOCs in Soils?
• They change over time
• "volatility"
• Most complicated medium is soil
• Samples are poorly preserved
• Can be locally homogenous in real world
• Present sampling procedures result in non-reproducible results
• Samples change in situ (e.g ., due to climate)
Additional Comments
• Know geology - use multi-disciplinary approach
• Take extra samples to store for litigation or other contingencies
• Spend money on sampling; we can accept imperfect analysis
• Recognize error level in data; demonstrate how bad present methods are and what their
effect is on risk assessment and risk management decisions with a "white paper"
• Validity of sampling error is unimportant compared to administrative (regulatorv)
problem J
Issues
The discussion did not deal only with VOCs as a unique problem, but became generic at times
The overriding issues seemed to be how to influence the bureaucracy to allow for improvement in
technology to be transferred into full use. The scientists seem to know what to do, but they are
constrained by a system they can't control. There was a definite consensus that VOCs in soil are
being underestimated with our present methodologies and therefore, risks are not being adequately
addressed. ^ J
1. Sample Integrity: Holding times, Handling/Preservation, Containers
• Present practice: 14 days holding, no preservation
• Recommendations/Comments:
o Write into QA plans
o Do instant analysis
39
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o Preserve instantly (e.g., methanol in field)
o Publish, promulgate appropriate methods
o Need EPA acceptance and more research
2. Dealing with Precedents
• Present practice: lawyers insist
• Recommendations:
o Ifputinworkplan, it should be acceptable
3. Acceptability of New Methods
• Present practice: Encounter resistance from contractors, regulators, lawyers, QA people
• Recommendation/Comments:
o Need bench tests, pilot tests, and EPA approval
o Appropriate methodology depends on level of contamination; i.e., purge and trap
may be good for high levels
4. Mechanism for Disseminating New Technologies
• Present practice: DOE has system in place called TIE (Technical Information Exchange),
EPA has Field Methods Compendium
• Recommendations/Comments:
o Need informal exchange mechanism
o "Advertise", "sell" at EPA et al.
o Educate, consolidate
o Need policy memo(s) from EPA encouraging or allowing use of new technologies
5. Adequacy of Sample Design (includes sub-issues such as number of samples taken,
compositing, and filtering)
• Present Practice: should be part of DQO process, but use of DQOs is inadequate
• Recommendation/Comments:
o Identify the questions to be answered; will sample collection and analysis meet the
intended use of the data?
o Generally, need to take more samples to increase representativeness
o Get local regulators to accept Sampling and Analysis Plans (S APs)
o Use field methods to increase sample numbers and representativeness
o Involve data user in scoping/planning (i.e., risk assessor)
6. Limited Resources
• Recommendations/Comments:
o Use field methods to generate more data for same cost
o Need to balance cost with sample collection and analysis
7. Data Collection Usable to User
• Present Practice: Guidance's are available for DQOs and Data Useability (Guidance for
Data Useability in Risk Assessment in final, 1992; Guidance for Data Useability in Site
Assessment, and ...Removal are drafts)
• Recommendations/Comments:
o Know acceptable uncertainty for risk vs. remediation, removal, etc.
o Train field samplers
o Use multi-disciplinary approach in site planning, etc.
o Samplers need familiarity with what data will be used for
o User can assist in sample collection (biologist sometimes used to assist m sample
40
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collection for ecological assessment)
8. Uncertainties
• Recommendations/Comments:
o First step is to have "reliable analysis"
Report bias, conditions, "pedigree"
Use complimentary methods (i.e., field with fixed lab confirmatory)
Increase number of samples
Provide field oversight audits
o
o
o
o
9. Performance Evaluation Samples
• Present Practice: problems with development
• Recommendations/Comments:
o Can contribute to quantification of uncertainty/error
o Not certain what they assure
o Needs research and methodology development
10. Mixed Waste
• Present practice: interaction with radionuclides
• Recommendations
o Need methods development
D.2 Responses and Remarks of Working Group 2
Remarks made by participants involved in Working Group 2 discussions were recorded by the
facilitators, Martin Stutz and Dave Bottrell. A summary of the information exchanged is given in
Table D.I.
1.
D.3 Responses and Remarks of Working Group 3
Remarks made by participants involved in Working Group 3 discussions were recorded by the
facilitators, Joan Fisk and Dean Neptune. The issue that the group chose to focus on was
sampling and analysis planning and data assessment (e.g., modification of discussion question
number 6 (See Appendix Q). A summary of the information exchanged is given below.
"How can field analysis or screening be used to optimize the collection of VOCs in soil data?
How can we gain acceptance of the use of field analyses for VOCs in soil data?"
• What do we want to use the data for?
o Identification of the site problem
o Definition of the magnitude of the problem
o Assurance that risk has been adequately reduced.
• Present Practices
o Only "CLP Quality" data can be used for decision making
o There is a perception that field methods are inferior
o The is a perception that only the "best" quality data may be used in risk assessment
• Comments
o Marketing field methods is necessary
o Field methods performance is not documented
o There must be flexibility built into the data collection process concerning analytical
methods/number of samples
41
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Table D.I. Remarks made and recorded during discussions in Working Group 2.
Issues
Extreme
data
variability
(Vapor phase
transport)
Present practices Comments
A11VOC
treated the same
Presumption of
no loss in
sampling/transport
Recommendations
Little formal DQO
Define problem
No automatic answers
Types of data
-Lab
- Field measurement
- Soil gas
SW-846, 8240
No efficient integration of
historical and current soil
studies
Sample
composting
- Integrity
-Utility
Dissemination
of methods/
alternatives
Guidance as
"Leading Edge"
Current sampling
sampling and
holding times
requirements
are not" Correct"
Mechanism to
implement
change
Don't attempt
without regulator
acceptance
"Miss or
miss"
"Guidance"
taken as
"Law"
Gross under
estimate of VOCs
None / slow
Dependent upon
procedures to
prevent loss
from handling,
e.g., methanol
preservation
Need mechanism
for distribution
Need to
convince
public
Develop guidance
when appropriate
and when not, e.g.,
detection limits
Individual
Responsibility, local
organization
EDUCATE,
EDUCATE
Need to identify and establish procedures
that preserve samples and "Take Better"
(more representative) samples
Need "Driving
Force"
Involvement of
external
organizations, e.g.,
API, CMA, etc
42
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e.g., Any combination of method (A) at $Z/sample with B #'s of samples that equal X
data performance is OK
Recommendations
o Develop a compendium of field methods
There must be flexibility built in by incorporation of performance criteria
Sampling methods must be included with documentation of the procedure and methods
performance
Appropriate QA/QC must be built in to assure adequacy and provide a measure of the
quality (user defined)
An effective tech transfer process must be developed
It must be a multi-agency effort
THIS METHOD COMPENDIUM WITH PERFORMANCE DATA MUST BE A
PRIORITY! (How can we leverage this issue to include support by the various
Agencies?)
2. Data Assessment
The data assessment process must be streamlined and results of assessment transferred to
multiple users for more efficient use of the data.
• Present Practices
o "Functional guidelines: approach - prescriptive
"DQOs" limited to CLP contract requirements
Generic definition of what is "good enough"
Perception that all criteria are absolute
Perception that all samples and analytes must be evaluated
Comments
o Data assessment must be related to DQOs
o There must be a process that starts with input from the DOS and continues with
evaluation of the output against DOS
o Timeliness of data availability to the users is crucial!
Recommendations
There must be a standardized electronic deliverable
Automated review must be implemented to allow streamlining
Consider review of a subset of the data set
Permutations of above
Allow DQOs to drive QC limits
Labs must be more involved with users and informed on DQOs to enable more
flexibility in analytical process to meet clients needs (> communication!)
Must streamline whole decision making process - not just data assessment (e.g., a
process approach)
Concurrent data processing
Statistician finds anomalies and tries to understand them rather than limiting the data
Must define "stopping points"
Must define what we are assessing, e.g.,
- contract compliance
- attainment of DQOs
- meeting of QC limits
integrity
Must identify what information must be collected for adequate assessment
Must define data quality identifiers needed for each analytical batch, e.g.,
- precision
- bias
data "pedigree"
site information
43
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APPENDIX E: BIBLIOGRAPHY
A selected number of references concerning VOCs in soil are contained in this Appendix. This
bibliography has been assembled based on references contained in the abstracts and publications
submitted for the Symposium proceedings notebook and from several other published sources.
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