ASTM D5314-92(2001)
(Guide)Standard Guide for Soil Gas Monitoring in the Vadose Zone
Standard Guide for Soil Gas Monitoring in the Vadose Zone
SCOPE
1.1 This guide covers information pertaining to a broad spectrum of practices and applications of soil atmosphere sampling, including sample recovery and handling, sample analysis, data interpretation, and data reporting. This guide can increase the awareness of soil gas monitoring practitioners concerning important aspects of the behavior of the soil-water-gas-contaminant system in which this monitoring is performed, as well as inform them of the variety of available techniques of each aspect of the practice. Appropriate applications of soil gas monitoring are identified, as are the purposes of the various applications. Emphasis is placed on soil gas contaminant determinations in certain application examples.
1.2 This guide suggests a variety of approaches useful to successfully monitor vadose zone contaminants with instructions that offer direction to those who generate and use soil gas data.
1.3 This guide does not recommend a standard practice to follow in all cases nor does it recommend definite courses of action. The success of any one soil gas monitoring methodology is strongly dependent upon the environment in which it is applied.
1.4 Concerns of practitioner liability or protection from or release from such liability, or both, are not addressed by this guide.
1.5 This guide is organized into the following sections and subsections that address specific segments of the practice of monitoring soil gas:Section4Summary of Practice4.1Basic principles, including partitioning theory, migration and emplacement processes, and contaminant degradation4.7Summary Procedure5Significance and Use6Approach and Procedure6.1Sampling Methodology6.5Sample Handling and Transport6.6Analysis of Soil Gas Samples6.7Data Interpretation7Reporting
1.6 This guide does not purport to set standard levels of acceptable risk. Use of this guide for purposes of risk assessment is wholly the responsibility of the user
1.7 The values stated in either inch-pound or SI units are to be regarded separately as the standard. The values given in parentheses are for information only.
1.8 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
1.9 This guide offers an organized collection of information or a series of options and does not recommend a specific course of action. This document cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this guide may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without consideration of a project's many unique aspects. The word "Standard" in the title of this document means only that the document has been approved through the ASTM consensus process.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D 5314 – 92 (Reapproved 2001)
Standard Guide for
Soil Gas Monitoring in the Vadose Zone
This standard is issued under the fixed designation D5314; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 1.6 This guide does not purport to set standard levels of
acceptable risk. Use of this guide for purposes of risk assess-
1.1 This guide covers information pertaining to a broad
ment is wholly the responsibility of the user.
spectrum of practices and applications of soil atmosphere
1.7 The values stated in either inch-pound or SI units are to
sampling, including sample recovery and handling, sample
be regarded separately as the standard. The values given in
analysis,datainterpretation,anddatareporting.Thisguidecan
parentheses are for information only.
increase the awareness of soil gas monitoring practitioners
1.8 This standard does not purport to address all of the
concerningimportantaspectsofthebehaviorofthesoil-water-
safety problems, if any, associated with its use. It is the
gas-contaminantsysteminwhichthismonitoringisperformed,
responsibility of the user of this standard to establish appro-
aswellasinformthemofthevarietyofavailabletechniquesof
priate safety and health practices and determine the applica-
eachaspectofthepractice.Appropriateapplicationsofsoilgas
bility of regulatory limitations prior to use.
monitoring are identified, as are the purposes of the various
1.9 This guide offers an organized collection of information
applications. Emphasis is placed on soil gas contaminant
or a series of options and does not recommend a specific
determinations in certain application examples.
course of action. This document cannot replace education or
1.2 This guide suggests a variety of approaches useful to
experienceandshouldbeusedinconjunctionwithprofessional
successfully monitor vadose zone contaminants with instruc-
judgment.Notallaspectsofthisguidemaybeapplicableinall
tionsthatofferdirectiontothosewhogenerateandusesoilgas
circumstances. This ASTM standard is not intended to repre-
data.
sent or replace the standard of care by which the adequacy of
1.3 This guide does not recommend a standard practice to
a given professional service must be judged, nor should this
follow in all cases nor does it recommend definite courses of
documentbeappliedwithoutconsiderationofaproject’smany
action. The success of any one soil gas monitoring methodol-
unique aspects. The word “Standard” in the title of this
ogy is strongly dependent upon the environment in which it is
document means only that the document has been approved
applied.
through the ASTM consensus process.
1.4 Concerns of practitioner liability or protection from or
release from such liability, or both, are not addressed by this
2. Referenced Documents
guide.
2.1 ASTM Standards:
1.5 This guide is organized into the following sections and
D653 Terminology Relating to Soil, Rock, and Contained
subsections that address specific segments of the practice of
Fluids
monitoring soil gas:
D1356 Terminology Relating to Atmospheric Sampling
Section
and Analysis
4 Summary of Practice
4.1 Basic principles, including partitioning theory, migration and em-
D1357 Practice for Planning the Sampling of the Ambient
placement processes, and contaminant degradation
Atmosphere
4.7 Summary Procedure
D1452 Practice for Soil Investigation and Sampling by
5 Significance and Use
6 Approach and Procedure
Auger Borings
6.1 Sampling Methodology
D1605 PracticesforSamplingAtmospheresforAnalysisof
6.5 Sample Handling and Transport
Gases and Vapors
6.6 Analysis of Soil Gas Samples
6.7 Data Interpretation
D1914 Practice for Conversion Units and Factors Relating
7 Reporting
to Atmospheric Analysis
D 2652 Terminology Relating to Activated Carbon
ThisguideisunderthejurisdictionofASTMCommitteeD18onSoilandRock
and is the direct responsibility of Subcommittee D18.21 on Ground Water and Annual Book of ASTM Standards, Vol 04.08.
Vadose Zone Investigations. Annual Book of ASTM Standards, Vol 11.03.
Current edition approved Nov. 15, 1992. Published January 1993. Annual Book of ASTM Standards, Vol 15.01.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 5314 – 92 (2001)
D2820 Test Method for C Through C Hydrocarbons in 3.1.5 free vapor phase—a condition of contaminant resi-
1 5
the Atmosphere by Gas Chromatography dence in which volatilized contaminants occur in porosity that
D3249 Practice for General Ambient Air Analyzer Proce- is effective to free and open gaseous flow and exchange, such
dures porosity generally being macroporosity.
D3416 Test Method forTotal Hydrocarbons, Methane, and 3.1.6 liquid phase—contaminant residing as a liquid in
Carbon Monoxide (Gas Chromatographic Method) in the vadose zone pore space, often referred to as “free product.”
Atmosphere 3.1.7 macroporosity—large intergranular porosity with
D3584 Practice for Indexing Papers and Reports on Soil large pore throats, including soil cracks, moldic porosity,
and Rock for Engineering Purposes animal burrows and other significant void space.
D3614 Guide for Laboratories Engaged in Sampling and 3.1.8 microporosity—intragranular porosity and micro-
Analysis of Atmospheres and Emissions scopicintergranularporositywithsubmicroscopicporethroats.
D3670 Guide for Determination of Precision and Bias of 3.1.9 occludedvaporphase—conditionofcontaminantresi-
Methods of Committee D-22 dence in which volatilized contaminants occur in porosity that
D3686 Practice for Sampling Atmospheres to Collect Or- isineffectivetofreeandopengaseousflowandexchange,such
ganic Compound Vapors (Activated Charcoal Tube Ad- porosity generally being microporosity; frequently termed
sorption Method) dead-end pore space.
D3687 Practice forAnalysis of Organic CompoundVapors 3.1.10 partitioning—the act of movement of contaminants
Collected by the Activated Charcoal Tube Adsorption from one soil residence phase to another.
Method 3.1.11 soil gas—vadose zone atmosphere.
D4220 Practices for Preserving and Transporting Soil 3.1.12 solute phase—a condition of contaminant residence
Samples in which contaminants are dissolved in ground water in either
D4490 Practice for Measuring the Concentration of Toxic the saturated or the vadose zone.
Gases or Vapors Using Detector Tubes 3.1.13 sorbed phase—a condition of contaminant residence
D4597 Practice for Sampling Workplace Atmospheres to in which contaminants are adsorbed onto the surface of soil
Collect Organic Gases or Vapors withActivated Charcoal particles or absorbed by soil organic matter.
Diffusional Samplers 3.1.14 vadose zone—the hydrogeological region extending
D4696 Guide for Pore-Liquid Sampling from the Vadose from the soil surface to the top of the principal water table.
Zone
4. Summary of Guide
D4700 Guide for Soil Core Sampling from the Vadose
Zone
4.1 Soilgasmonitoringinthevadosezoneisamethodused
D5088 Practice for the Decontamination of Field Equip- to directly measure characteristics of the soil atmosphere that
ment Used at Non Radioactive Waste Sites
are frequently utilized as an indirect indicator of processes
E177 Practice for Use of the Terms Precision and Bias in occurring in and below a sampling horizon. Soil gas monitor-
ASTM Test Methods
ing is used as a method to suggest the presence, composition,
E260 Practice for Packed Column Gas Chromatography
and origin of contaminants in and below the vadose zone.
E355 PracticeforGasChromatogaphyTermsandRelation-
Among other applications, this method is also employed in the
ships
exploration for natural resources, including petroleum, natural
E594 Practice forTesting Flame Ionization Detectors Used gas and precious metals. Soil gas monitoring is a valuable
in Gas Chromatography
screening method for detection of volatile organic contami-
E697 Practice for Use of Electron-Capture Detectors in nants, the most abundant analytical group of ground-water
7 8
Gas Chromatography
contaminant compounds (1).
4.2 Basic Theoretical Principles—The processes indicated
3. Terminology
by the soil gas monitoring method are partitioning, migration,
3.1 Definitions of Terms Specific to This Standard:
emplacement and degradation. Partitioning represents a group
3.1.1 capillary fringe—the basal region of the vadose zone
of processes that control contaminant movement from one
comprising sediments that are saturated, or nearly saturated,
physicalphasetoanother,thesephasesbeingliquid,freevapor
nearthewatertable,graduallydecreasinginwatercontentwith
(that is, through-flowing air (2)), occluded vapor (that is,
increasing elevation above the water table.Also see Terminol-
locally accessible air and trapped air (2)), solute and sorbed.
ogy D653.
Migration refers to contaminant movement over distance with
3.1.2 contaminant—substances not normally found in an
any vertical, horizontal or temporal component. Emplacement
environment at the observed concentration.
refers to establishment of contaminant residence in any phase
3.1.3 emplacement—the establishment of contaminant resi-
within any residence opportunity. Degradation is the process
dence in the vadose zone in a particular phase.
wherebycontaminantsareattenuatedbyoxidationorreduction
3.1.4 free product—liquid phase contaminants released into
in the vadose zone, either through biogenic or abiogenic
the environment.
processes. Soil gas monitoring measures the result of the
Annual Book of ASTM Standards, Vol 04.09.
6 8
Annual Book of ASTM Standards, Vol 14.02. The boldface numbers given in parentheses refer to a list of references at the
Annual Book of ASTM Standards, Vol 14.01. end of the text.
D 5314 – 92 (2001)
interaction of these processes in a dynamic equilibrium. phase components in water beyond what is indicated by
Measurement of these processes in static equilibrium is unre- partitioning coefficient data generated in the laboratory. This
alistic. can have significant impact on downstream concentrations of
4.3 The following subsections provide detailed information the contaminant(s) in the soil atmosphere.
4.3.2.2 The effects of temperature upon dissolution equilib-
onpartitioning,migration,emplacementanddegradation.Sub-
section 4.4 provides a summary procedure for soil gas sam- rium are generally insignificant for aliphatic hydrocarbons
pling. Users of this guide who do not wish to study details of between 15 and 50°C (4), the temperature range from which
partitioning, migration, emplacement and degradation at this most soil gas samples are recovered. However, temperature
time may skip to 4.4. effectsupondissolutionequilibriumcanbesignificantforother
4.3.1 Partitioning is the initial step by which contaminants common families of contaminant compounds within similar
temperatureranges (5).Theseeffectsmustbeconsideredwhen
begin to move away from their source. Partitioning occurs in
water saturated and unsaturated environments. This group of planning or interpreting the results of a soil gas survey.
4.3.2.3 Dissolution equilibrium is altered by changes in
processes is complex and difficult to quantify when considered
in the vadose zone due to the unique makeup of the vadose water salinity. Modest decreases in the solubility of contami-
nants in water are to be expected with increases in salinity of
matrix, i.e. air-filled porosity (microporous and macroporous),
the solution.
pore water, free product, solid-phase soil organic matter, clay
4.3.2.4 The rate of dissolution is strongly dependent upon
and discrete inorganic soil particles. Important individual
the partitioning coefficient of the particular contaminant of
processes of partitioning are dissolution, volatilization, air-
waterpartitioning,soil-waterpartitioningandsoil-airpartition- interestandtheamountofmixingoftheliquidphaseandwater
(3). For example, partitioning of a particular contaminant into
ing (3).
groundwaterisacceleratedbyfrequentwaterlevelfluctuations
4.3.2 Dissolution is the process whereby volatile contami-
within a contaminated capillary fringe. The downstream im-
nants move between the liquid phase (free product) and the
plications for subsequent partitioning of the contaminant from
solute phase (dissolved in water). At equilibrium, the product
the solute to the vapor phase for eventual soil gas recovery are
of the mole fraction of a particular compound in the liquid
obvious.
phaseandtheactivitycoefficientofthatcompoundintheliquid
4.3.3 Volatilization is the process during which volatile
phase is equal to the product of the mole fraction of that
contaminants move between the liquid phase (free product) or
compound in the solute phase and the activity coefficient of
solute phase and a vapor phase, either the free vapor phase or
thatcompoundinthesolutephase.Thisprocessismoreclearly
the occluded vapor phase or both. Contaminant mixtures can
described by the following expression:
contain compounds with a considerable range of vapor pres-
L L W W
X G 5X G (1)
I I I I
sures that can contribute contaminants to the soil atmosphere
by volatilization. This atmosphere will exhibit a composition
where:
L
similar to that of the parent contaminant but lacking in those
X = the mole fraction of compound ( I) in the liquid (L)
I
constituents with the lowest vapor pressures.The likelihood of
phase (free product),
W
the presence of a particular contaminant introduced into the
X = themolefractionofcompound(I)inthesolute(W)
I
phase (dissolved in water), soil atmosphere by volatilization can be estimated by consid-
L
G = theactivitycoefficientofcompound(I)intheliquid ering the partial pressure of that contaminant in a vapor phase.
I
(L) phase (free product), and
Thispartialpressureisequaltotheproductofthemolefraction
W
G = theactivitycoefficientofcompound(I)inthesolute
concentration of the subject component in the liquid contami-
I
(W) phase (dissolved in water).
nant solution, the activity coefficient of the subject component
Dissolution equilibrium is therefore influenced by concen- and the vapor pressure of the pure component. This concept is
tration of the subject compound in both the free product
more clearly expressed as follows:
contaminant mixture and water. The most common practical
o
P 5X GP (3)
I I
application of expression (Eq 1) in soil gas monitoring is in
hydrocarbon detection. Simplification of (Eq 1) is achieved by
where:
the following:
P = the partial pressure of the subject contaminant com-
assume: pound in the vapor phase,
W
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.