ASTM E3300-21
(Guide)Standard Guide for NAPL Mobility and Migration in Sediment- Evaluating Ebullition and Associated NAPL/Contaminant Transport
Standard Guide for NAPL Mobility and Migration in Sediment- Evaluating Ebullition and Associated NAPL/Contaminant Transport
SIGNIFICANCE AND USE
4.1 Ebullition is ubiquitous in sediment and is primarily a significant concern when there is associated NAPL/contaminant transport, resulting in exposure risk to humans, ecological receptors, or both. Ebullition may also be a concern when capping has been chosen as part of a site remedy.
4.2 Understanding the potential for ebullition-facilitated NAPL/contaminant transport in sediment is an important element of an overall conceptual site model (CSM) that forms a basis for (1) evaluating if (and how) human and ecological receptors may be exposed to NAPL/contaminants, and (2) assessing remedial alternatives. In addition, demonstrating the potential for (and extent of) ebullition-facilitated transport of NAPL/contaminants in sediments to regulators and other stakeholders has been historically hampered by the lack of standardized terminology and characterization protocols. The complexity of ebullition-facilitated NAPL/contaminant transport in sediment, and the lack of agreed upon methods for analysis and interpretation of site data, has led to uncertainty in corrective action decision-making at sediment sites. This has sometimes resulted in misleading expectations about remedial outcomes. The ebullition-facilitated transport mechanisms for NAPL/contaminants in sediments are different from advective transport mechanisms in sediment or in upland environments, due to a variety of physical, geochemical, and biological differences, thus necessitating this guide.
4.3 This guide is intended to serve as a stand-alone document to consider conditions that are unique to ebullition and ebullition-facilitated NAPL/contaminant transport, as well as to complement other guides used for CSM development at contaminated sediment sites (Guides E1689, E1739, E2081, E2531, and E3248). This guide will aid users in understanding the unique and fundamental characteristics of sediment environments that influence the occurrence of ebullition-facilitated NAPL/contaminant transport. Understan...
SCOPE
1.1 This guide addresses the processes that lead to (or influence) ebullition-facilitated nonaqueous phase liquid (NAPL)/contaminant transport, methods for quantifying that transport, considerations for sample timing, sampling procedures, and use of results in extrapolating an annual ebullition-facilitated NAPL/contaminant load to a site, or a portion of a site. This guide is not intended to address remediation of sites where ebullition-facilitated transport of NAPL/contaminants is occurring, fate and transport of contaminants subsequent to the ebullition transport mechanism, the measurement of contaminant concentrations within the gas bubbles, ebullition-associated human health and ecological risk, NAPL advection, or determining the depth of ebullition below the mudline. Additionally, gas transport without NAPL/contaminants is possible in areas with gas generation and limited NAPL contamination of the sediment, which is covered in this guide. Ebullition should be evaluated at sites where sediment capping is anticipated.
1.2 The users of this guide should be aware of the appropriate regulatory requirements that apply to sediment sites where NAPL is present or suspected to occur. The user should consult applicable regulatory agency requirements to identify appropriate technical decision criteria and seek regulatory approvals, as necessary.
1.3 ASTM standard guides are not regulations; they are consensus standard guides that may be followed voluntarily to support applicable regulatory requirements. This guide may be used in conjunction with other ASTM guides developed for sediment programs. The guide supplements characterization and remedial efforts performed under international, federal, state, and local environmental programs, but it does not replace regulatory agency requirements.
1.4 The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard. ...
General Information
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Frequently Asked Questions
ASTM E3300-21 is a guide published by ASTM International. Its full title is "Standard Guide for NAPL Mobility and Migration in Sediment- Evaluating Ebullition and Associated NAPL/Contaminant Transport". This standard covers: SIGNIFICANCE AND USE 4.1 Ebullition is ubiquitous in sediment and is primarily a significant concern when there is associated NAPL/contaminant transport, resulting in exposure risk to humans, ecological receptors, or both. Ebullition may also be a concern when capping has been chosen as part of a site remedy. 4.2 Understanding the potential for ebullition-facilitated NAPL/contaminant transport in sediment is an important element of an overall conceptual site model (CSM) that forms a basis for (1) evaluating if (and how) human and ecological receptors may be exposed to NAPL/contaminants, and (2) assessing remedial alternatives. In addition, demonstrating the potential for (and extent of) ebullition-facilitated transport of NAPL/contaminants in sediments to regulators and other stakeholders has been historically hampered by the lack of standardized terminology and characterization protocols. The complexity of ebullition-facilitated NAPL/contaminant transport in sediment, and the lack of agreed upon methods for analysis and interpretation of site data, has led to uncertainty in corrective action decision-making at sediment sites. This has sometimes resulted in misleading expectations about remedial outcomes. The ebullition-facilitated transport mechanisms for NAPL/contaminants in sediments are different from advective transport mechanisms in sediment or in upland environments, due to a variety of physical, geochemical, and biological differences, thus necessitating this guide. 4.3 This guide is intended to serve as a stand-alone document to consider conditions that are unique to ebullition and ebullition-facilitated NAPL/contaminant transport, as well as to complement other guides used for CSM development at contaminated sediment sites (Guides E1689, E1739, E2081, E2531, and E3248). This guide will aid users in understanding the unique and fundamental characteristics of sediment environments that influence the occurrence of ebullition-facilitated NAPL/contaminant transport. Understan... SCOPE 1.1 This guide addresses the processes that lead to (or influence) ebullition-facilitated nonaqueous phase liquid (NAPL)/contaminant transport, methods for quantifying that transport, considerations for sample timing, sampling procedures, and use of results in extrapolating an annual ebullition-facilitated NAPL/contaminant load to a site, or a portion of a site. This guide is not intended to address remediation of sites where ebullition-facilitated transport of NAPL/contaminants is occurring, fate and transport of contaminants subsequent to the ebullition transport mechanism, the measurement of contaminant concentrations within the gas bubbles, ebullition-associated human health and ecological risk, NAPL advection, or determining the depth of ebullition below the mudline. Additionally, gas transport without NAPL/contaminants is possible in areas with gas generation and limited NAPL contamination of the sediment, which is covered in this guide. Ebullition should be evaluated at sites where sediment capping is anticipated. 1.2 The users of this guide should be aware of the appropriate regulatory requirements that apply to sediment sites where NAPL is present or suspected to occur. The user should consult applicable regulatory agency requirements to identify appropriate technical decision criteria and seek regulatory approvals, as necessary. 1.3 ASTM standard guides are not regulations; they are consensus standard guides that may be followed voluntarily to support applicable regulatory requirements. This guide may be used in conjunction with other ASTM guides developed for sediment programs. The guide supplements characterization and remedial efforts performed under international, federal, state, and local environmental programs, but it does not replace regulatory agency requirements. 1.4 The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard. ...
SIGNIFICANCE AND USE 4.1 Ebullition is ubiquitous in sediment and is primarily a significant concern when there is associated NAPL/contaminant transport, resulting in exposure risk to humans, ecological receptors, or both. Ebullition may also be a concern when capping has been chosen as part of a site remedy. 4.2 Understanding the potential for ebullition-facilitated NAPL/contaminant transport in sediment is an important element of an overall conceptual site model (CSM) that forms a basis for (1) evaluating if (and how) human and ecological receptors may be exposed to NAPL/contaminants, and (2) assessing remedial alternatives. In addition, demonstrating the potential for (and extent of) ebullition-facilitated transport of NAPL/contaminants in sediments to regulators and other stakeholders has been historically hampered by the lack of standardized terminology and characterization protocols. The complexity of ebullition-facilitated NAPL/contaminant transport in sediment, and the lack of agreed upon methods for analysis and interpretation of site data, has led to uncertainty in corrective action decision-making at sediment sites. This has sometimes resulted in misleading expectations about remedial outcomes. The ebullition-facilitated transport mechanisms for NAPL/contaminants in sediments are different from advective transport mechanisms in sediment or in upland environments, due to a variety of physical, geochemical, and biological differences, thus necessitating this guide. 4.3 This guide is intended to serve as a stand-alone document to consider conditions that are unique to ebullition and ebullition-facilitated NAPL/contaminant transport, as well as to complement other guides used for CSM development at contaminated sediment sites (Guides E1689, E1739, E2081, E2531, and E3248). This guide will aid users in understanding the unique and fundamental characteristics of sediment environments that influence the occurrence of ebullition-facilitated NAPL/contaminant transport. Understan... SCOPE 1.1 This guide addresses the processes that lead to (or influence) ebullition-facilitated nonaqueous phase liquid (NAPL)/contaminant transport, methods for quantifying that transport, considerations for sample timing, sampling procedures, and use of results in extrapolating an annual ebullition-facilitated NAPL/contaminant load to a site, or a portion of a site. This guide is not intended to address remediation of sites where ebullition-facilitated transport of NAPL/contaminants is occurring, fate and transport of contaminants subsequent to the ebullition transport mechanism, the measurement of contaminant concentrations within the gas bubbles, ebullition-associated human health and ecological risk, NAPL advection, or determining the depth of ebullition below the mudline. Additionally, gas transport without NAPL/contaminants is possible in areas with gas generation and limited NAPL contamination of the sediment, which is covered in this guide. Ebullition should be evaluated at sites where sediment capping is anticipated. 1.2 The users of this guide should be aware of the appropriate regulatory requirements that apply to sediment sites where NAPL is present or suspected to occur. The user should consult applicable regulatory agency requirements to identify appropriate technical decision criteria and seek regulatory approvals, as necessary. 1.3 ASTM standard guides are not regulations; they are consensus standard guides that may be followed voluntarily to support applicable regulatory requirements. This guide may be used in conjunction with other ASTM guides developed for sediment programs. The guide supplements characterization and remedial efforts performed under international, federal, state, and local environmental programs, but it does not replace regulatory agency requirements. 1.4 The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard. ...
ASTM E3300-21 is classified under the following ICS (International Classification for Standards) categories: 13.080.01 - Soil quality and pedology in general. The ICS classification helps identify the subject area and facilitates finding related standards.
ASTM E3300-21 has the following relationships with other standards: It is inter standard links to ASTM E2993-23, ASTM E3248-20, ASTM E3163-18, ASTM E2993-16, ASTM E1739-95(2015), ASTM E1739-95(2010)e1, ASTM E2081-00(2010)e1, ASTM E1689-95(2008), ASTM E2081-00(2004)e1, ASTM E2081-00, ASTM E1739-95(2002), ASTM E1739-95e1. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
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Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E3300 − 21
Standard Guide for
NAPL Mobility and Migration in Sediment— Evaluating
Ebullition and Associated NAPL/Contaminant Transport
This standard is issued under the fixed designation E3300; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope 1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This guide addresses the processes that lead to (or
responsibility of the user of this standard to establish appro-
influence) ebullition-facilitated nonaqueous phase liquid
priate safety, health, and environmental practices and deter-
(NAPL)/contaminant transport, methods for quantifying that
mine the applicability of regulatory limitations prior to use.
transport, considerations for sample timing, sampling
1.6 This international standard was developed in accor-
procedures, and use of results in extrapolating an annual
dance with internationally recognized principles on standard-
ebullition-facilitated NAPL/contaminant load to a site, or a
ization established in the Decision on Principles for the
portion of a site. This guide is not intended to address
Development of International Standards, Guides and Recom-
remediation of sites where ebullition-facilitated transport of
mendations issued by the World Trade Organization Technical
NAPL/contaminants is occurring, fate and transport of con-
Barriers to Trade (TBT) Committee.
taminants subsequent to the ebullition transport mechanism,
the measurement of contaminant concentrations within the gas
2. Referenced Documents
bubbles, ebullition-associated human health and ecological
risk, NAPL advection, or determining the depth of ebullition
2.1 ASTM Standards:
below the mudline.Additionally, gas transport without NAPL/
E1689Guide for Developing Conceptual Site Models for
contaminants is possible in areas with gas generation and
Contaminated Sites
limitedNAPLcontaminationofthesediment,whichiscovered
E1739Guide for Risk-Based Corrective Action Applied at
in this guide. Ebullition should be evaluated at sites where
Petroleum Release Sites
sediment capping is anticipated.
E2081Guide for Risk-Based Corrective Action
E2531Guide for Development of Conceptual Site Models
1.2 The users of this guide should be aware of the appro-
and Remediation Strategies for Light Nonaqueous-Phase
priate regulatory requirements that apply to sediment sites
Liquids Released to the Subsurface
where NAPLis present or suspected to occur. The user should
E2993Guide for Evaluating Potential Hazard as a Result of
consult applicable regulatory agency requirements to identify
Methane in the Vadose Zone
appropriate technical decision criteria and seek regulatory
E3163Guide for Selection and Application of Analytical
approvals, as necessary.
Methods and Procedures Used during Sediment Correc-
1.3 ASTM standard guides are not regulations; they are
tive Action
consensus standard guides that may be followed voluntarily to
E3248GuideforNAPLMobilityandMigrationinSediment
support applicable regulatory requirements.This guide may be
–Conceptual Models for Emplacement and Advection
used in conjunction with other ASTM guides developed for
sediment programs. The guide supplements characterization
3. Terminology
and remedial efforts performed under international, federal,
3.1 Definitions:
state,andlocalenvironmentalprograms,butitdoesnotreplace
3.1.1 biogenic, adj—resulting from the activity of living
regulatory agency requirements.
organisms (Guide E2993).
1.4 The values stated in SI units are to be regarded as the
3.1.2 contaminant, n—substance not normally found in an
standard. No other units of measurement are included in this
environment at the observed concentration (Guide E2993).
standard.
ThisguideisunderthejurisdictionofASTMCommitteeE50onEnvironmental
Assessment, Risk Management and CorrectiveAction and is the direct responsibil- For referenced ASTM standards, visit the ASTM website, www.astm.org, or
ity of Subcommittee E50.04 on Corrective Action. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Current edition approved Sept. 15, 2021. Published October 2021. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/E3300–21. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E3300 − 21
3.1.3 flux, n—mass crossing a unit area per unit time in any 3.2.8 flux chamber, n—a device with an isolation chamber
phase (for example, LNAPL, dissolved-phase, vapor-phase) that can trap gas bubbles rising through the water column.
(Guide E2531). 3.2.8.1 Discussion—Theisolationchamberisequippedwith
3.1.3.1 Discussion—For ebullition, the unit area of interest vent valve for sampling the headspace and measuring the
volume of accumulated gases.
is the sediment-water interface.
3.2.9 hydrogenotrophic organisms, n—microbial organisms
3.1.4 migrating NAPL, n—NAPL that can move at the
that use molecular hydrogen as a metabolic energy source.
NAPL body scale, such that the NAPL body may advectively
expand in at least one direction under observed or reasonably
3.2.10 labile organic matter, n—carbon-basedmaterialsthat
anticipated field conditions (Guide E3248).
can be consumed and broken down by microorganisms, with
the typical eventual metabolic end products being methane or
3.1.5 mobile NAPL, n—NAPLthat may move by advection
carbon dioxide, or both.
withintheconnectedvoidspacesofthesedimentunderspecific
physical and chemical conditions, as may be demonstrated by
3.2.11 mesophilic organisms, n—microbial organisms that
laboratory testing, or as may be interpreted based on math-
can grow at a moderate temperature range of 20 °C–45 °C
ematical calculations or modeling (Guide E3248).
with an optimum growth temperature in the range of 30
°C–39 °C.
3.1.6 non-aqueous phase liquid, n—chemicals that are in-
soluble or only slightly soluble in water that exist as a separate
3.2.12 methanogenesis, n—the generation of methane by
liquid phase in environmental media (Guide E3248).
microorganisms, typically through the consumption of labile
3.1.6.1 Discussion—NAPL may be less dense than water organic matter (OM).
(light non-aqueous phase liquid [LNAPL]) or more dense than
3.2.13 methanotrophic organisms, n—a group of microbial
water (dense non-aqueous phase liquid [DNAPL]).
organisms that utilize methane as a carbon source.
3.1.7 sediment—a matrix of porewater and particles includ-
3.2.14 nucleation, n—the initial formation of a separate gas
ing gravel, sand, silt, clay, and other natural and anthropogenic
phasebubbleinasurroundingliquidthatissupersaturatedwith
substances that have settled at the bottom of a tidal or nontidal
that gas.
body of water (Guide E3163).
3.2.15 oil-particle aggregate—OPA, n—aparticleformedin
3.2 Definitions of Terms Specific to This Standard:
a surface water body resulting from the adherence to (or
3.2.1 acetoclastic organisms, n—microbial organisms that
penetrationinto)anoildropletbymineralsororganicmaterial.
convert acetic acid to methane.
3.2.16 seep, n—a location that slowly releases small quan-
3.2.2 acetogenesis, n—the biological formation of acetic
tities of NAPL from sediments or other water interfaces
acid from carbon dioxide or organic acids.
3.2.16.1 Discussion—Seeps differ from ebullition because
the release of the NAPLfrom the sediments and the flux of the
3.2.3 cone sampler, n—a sampler that uses an inverted cone
NAPL across the sediment-water interface occur without
or funnel of sufficient size to trap and measure gas released
facilitation from gas bubbles. Seeps and ebullition can be
from the sediment.
coincident but they are fundamentally separate phenomena.
3.2.3.1 Discussion—The cone is typically connected to a
frame for supporting the sampler during field deployment and 3.2.17 sheen, n—asilvery,rainbow,ordarkrainbowfilmon
providesadditionalvolumeforgascollection.Thesamplercan the water surface.
be positioned near the sediment surface or within the water
3.2.18 sheen blossom, n—the emergence of NAPL trans-
column.
ported by a gas bubble at the water surface followed by
3.2.4 corral sampler, n—a sampler that consists of an spreading of NAPL into a sheen at the air-water interface.
inflatableboomtoisolatethegasmeasurementarea,withathin
3.2.19 tent sampler, n—a square or rectangular frame cov-
film placed over the sampling area to trap gas bubbles released
ered by a thin film to trap gas bubbles.
from the sediment.
3.2.19.1 Discussion—The film is equipped with a sampling
port for sample collection and measuring the total volume of
3.2.5 ebullition, n—a process of gas (primarily methane)
gastrappedbythesampler.Therectangularframefloatsonthe
generation in sediments where the quantity of gas generated is
water surface and can move vertically with changes in water
sufficient for gas bubbles to nucleate, grow, fracture the
depth.
sediment, and then escape into the overlying water body.
3.2.5.1 Discussion—Depending on the composition of a
4. Significance and Use
particular sediment, the gas bubbles generated and released by
ebullition may strip constituents out of the sediment and
4.1 Ebullition is ubiquitous in sediment and is primarily a
transport these into the overlying water.
significant concern when there is associated NAPL/
contaminant transport, resulting in exposure risk to humans,
3.2.6 ebullition active area, n—a subarea within a larger
ecological receptors, or both. Ebullition may also be a concern
ebullition study area where gas ebullition occurs consistently
when capping has been chosen as part of a site remedy.
during an ebullition survey.
3.2.7 ebullition rate, n—the rate of volumetric gas produc- 4.2 Understanding the potential for ebullition-facilitated
tionfromthesediment,measuredinmicromolesofgasperunit NAPL/contaminant transport in sediment is an important
surface area of sediment per unit of time. element of an overall conceptual site model (CSM) that forms
E3300 − 21
a basis for (1) evaluating if (and how) human and ecological 4.6 Many materials (for example, chlorinated solvents, pe-
receptors may be exposed to NAPL/contaminants, and (2) troleum products, and creosote) enter the subsurface as an
assessing remedial alternatives. In addition, demonstrating the immiscible liquid, known as NAPL, which may flow as a
potential for (and extent of) ebullition-facilitated transport of separate phase from water. NAPL can contain contaminants,
NAPL/contaminants in sediments to regulators and other such as polycyclic aromatic hydrocarbons (PAHs).
stakeholders has been historically hampered by the lack of 4.6.1 Sheens may be observed on the surface of the water
standardized terminology and characterization protocols. The body from sources other than ebullition, such as natural/
complexity of ebullition-facilitated NAPL/contaminant trans- biogenic sheens, advective NAPL/contaminant transport, out-
port in sediment, and the lack of agreed upon methods for falls (for example, municipal and industrial), or vessel leaks.
analysisandinterpretationofsitedata,hasledtouncertaintyin Identifyingsourcesofsheensotherthanebullitionisnotwithin
corrective action decision-making at sediment sites. This has the scope of this guide.
sometimes resulted in misleading expectations about remedial
4.7 ThisguideassumesthataCSMhasbeendevelopedthat
outcomes. The ebullition-facilitated transport mechanisms for
includes the nature and extent of NAPL/contaminants in
NAPL/contaminants in sediments are different from advective
sediment.ThisCSMwouldincludeanunderstandingof (1)the
transport mechanisms in sediment or in upland environments,
hydrological setting, (2) the physical and chemical character-
due to a variety of physical, geochemical, and biological
istics of the sediment and water body, (3) the physical and
differences, thus necessitating this guide.
chemical characteristics of the NAPL/contaminants, (4)
mechanism(s) of NAPL/contaminant emplacement, (5) the
4.3 This guide is intended to serve as a stand-alone docu-
physical extent of the NAPL/contaminant zone, and (6) the
ment to consider conditions that are unique to ebullition and
potential for human and ecological exposures to NAPL/
ebullition-facilitated NAPL/contaminant transport, as well as
contaminantsinsediment,orviaNAPL/contaminantreleaseto
to complement other guides used for CSM development at
overlyingsurfacewater.Themeansandmethodsforcollecting
contaminated sediment sites (Guides E1689, E1739, E2081,
this information are not addressed in this guide.
E2531, and E3248).This guide will aid users in understanding
the unique and fundamental characteristics of sediment envi-
4.8 This guide assumes that the user has developed a CSM
ronments that influence the occurrence of ebullition-facilitated
that provides a framework for developing a conceptual model
NAPL/contaminant transport. Understanding the site charac-
(CM)thatisacomponentoftheoverallCSM,whichaddresses
teristicsthatinfluenceebullition-facilitatedNAPL/contaminant
ebullition-facilitated NAPL/contaminant transport. This guide
transport within the sediment column will aid in identifying
will help users understand the physical and chemical condi-
specific data requirements necessary to investigate these
tions and emplacement mechanisms that lead to (or influence)
conditions, which will enable further refinement of the CSM
ebullition-facilitated NAPL/contaminant transport, as well as
and provide a sound basis for remedy decisions.
aid in prioritizing and executing methods for gathering field
data and interpreting results to support the development of a
4.4 Ebullition-facilitatedNAPL/contaminanttransportisthe
CSM for the site.
primary transport mechanism that is addressed within this
4.8.1 The elements of the ebullition-facilitated NAPL/
guide.
contaminant transport CM describe the physical and chemical
4.4.1 In addition to ebullition-facilitated NAPL/
properties of the environment, the hydraulic conditions, the
contaminant transport, porewater advection may also facilitate
sourceoftheNAPL/contaminants,andthenatureandextentof
NAPL/contaminant transport; however, this process is beyond
the NAPL/contaminant zone. The CM is a dynamic, evolving
the scope of this guide. Advective transport of NAPL in
model that will change through time as new data are collected
sediments is addressed in Guide E3248.
and evaluated or as physical conditions of the site change due
4.4.2 Processes associated with NAPL/contaminant trans-
to natural or engineered processes. The goal of the CM is to
portduetoerosion(forexample,propellerwash)arenotwithin
describe the nature, distribution, and setting of the NAPL/
the scope of this guide.
contaminants in sufficient detail, so that questions regarding
4.5 This guide identifies the relevant information necessary currentandpotentialfuturerisks,longevity,andamenabilityto
remedial action can be adequately addressed.
foratechnicallyreliableandcomprehensiveCSMinsupportof
the investigation or remediation of ebullition-facilitated 4.8.2 The elements for the ebullition-facilitated NAPL/
contaminant transport CM may include, but are not limited to:
NAPL/contaminant transport in sediments. It describes the
conditions that lead to (or influence) ebullition-facilitated 4.8.2.1 Factors affecting the rate of gas production:
(1)Presence of microbial consortia capable of OM miner-
NAPL/contaminant transport, methods for quantifying the
ebullition-facilitated NAPL/contaminant flux rate, consider- alization
(2)Presence of labile OM
ations for field measurements, and use of field results in
extrapolating the NAPL/contaminant flux rate. A technically (3)Geochemical conditions conducive to methanogenesis
(4)Sediment temperature
reliable and comprehensive CSM will result in a more efficient
and consistent investigation of ebullition-facilitated NAPL/ 4.8.2.2 Factors affecting the nucleation of gas bubbles,
contaminant transport in sediments to support remedy deci- bubble growth and migration through the sediment column:
sions. This guide may also be beneficial for evaluating ebulli- (1)Availability of nucleation sites
tion alone at sites (for example, as input into sediment cap (2)Sediment properties (for example, tensile strength,
design). grain size, porosity, bulk density, cohesion, and heterogeneity)
E3300 − 21
(3)Porewater properties (for example, gas concentrations, 5. Fundamentals and Considerations During
salinity, pH, and geochemistry) Development of a Conceptual Site Model
(4) Environmental setting (for example, hydrostatic
5.1 Biogenic gases are generated in porewater as the result
pressure, atmospheric pressure, and groundwater seepage)
of microbial-facilitated degradation of OM. Ebullition-active
4.8.2.3 PresenceandextentoftheNAPL/contaminantzone,
sediment is typically rich in OM, which can originate from
including identification of where it is collocated with active
naturally occurring vegetation and organisms, as well as
ebullition zones.
anthropogenic sources. The following sections provide an
4.8.2.4 Ebullition-facilitated NAPL/contaminant transport
overview of gas ebullition and ebullition-facilitated transport
rates, including spatial and temporal variability:
of NAPL/contaminant processes, including factors that affect
(1)Screening-level evaluations
gas ebullition rates and NAPL/contaminant fluxes.
(2)Quantitative evaluations
5.2 Biogenic gases are end products from the microbial
4.9 The user of this guide should review the overall struc-
degradation of OM, through various metabolic pathways that
ture and components of this guide before proceeding with use, depend on availability of specific electron acceptors. The
including: primary biogenic gases produced include CH,CO , and to a
4 2
lesser extent N and H S. Sulfate reduction and denitrification
4.9.1 Section 1: Scope;
2 2
are energetically more favorable but produce lesser quantities
4.9.2 Section 2: Referenced Documents;
of N and H S. This is due to the limited availability of the
2 2
4.9.3 Section 3: Terminology;
− 2−
external electron acceptors (NO ,SO ) in sediments and
3 4
4.9.4 Section 4: Significance and Use;
presence of competing electron acceptors, such as oxygen,
4.9.5 Section 5: Fundamentals and Considerations During
manganese, and iron. The energetics of biochemical reactions
Development of a Conceptual Site Model
dictate that methane production can start only after the deple-
4.9.6 Section 6: Initial Screening for Gas Ebullition and
tion of all other more energetically favorable terminal electron
Ebullition Flux Measurement;
acceptors and under strictly anaerobic conditions. Methane
4.9.7 Section 7: Gas Ebullition Measurement;
productionisobservedbeneaththezoneofsulfatereductionin
4.9.8 Section 8: Quantification of Ebullition-Facilitated
sediments.Methaneconcentrationsinbiogenicgasesproduced
Transport of NAPL/Contaminants;
in sediments may range from 11% to 79 %, depending on the
4.9.9 Section9:FieldConsiderationsintheMeasurementof
predominant gas production pathway (1), (2), (3). Additional
NAPL/Contaminant Fluxes;
detailconcerningthegenerationofbiogenicgasesinsediments
4.9.10 Section 10: Keywords; is presented in Appendix X1
4.9.11 Appendix X1: Organic Matter Degradation and Mi-
5.3 Factors affecting the rate of gas production (including
crobiology of Biogenic Gas Production in Sediments;
how rates are affected) are summarized below and provided in
4.9.12 Appendix X2: Carbon Source Identification Using
more detail in Table 1. For methanogenesis to occur, microbial
Radioisotope Analysis;
consortia capable of complete OM mineralization to CH4 and
4.9.13 AppendixX3:BenchScaleTestingforBiogenicGas; CO arerequiredtobepresent.Thesemicrobialconsortianeed
and sufficient labile OM (naturally occurring, anthropogenic, or
both) and favorable geochemical conditions (anoxic redox
4.9.14 References.
conditions, electron acceptors present, favorable pH condi-
4.10 This guide provides an overview of the unique char-
tions). Additionally, sediment temperature influences the rate
acteristicsinfluencingebullition-facilitatedNAPL/contaminant
of microbial activity and gas generation; this changes season-
transport in aquatic sediment environments. This guide is not
ally and can be impacted by sediment depth, water depth, and
intended to provide specific guidance on sediment site
groundwater (4). Relatively high sediment temperature affects
investigation, risk assessment, monitoring, or remedial action.
gas production by stimulating the growth and activity of the
4.10.1 This guide may be used by various parties involved
microorganisms that degrade organic material and are respon-
in a sediment site, including regulatory agencies, project
sible for gas production. Less gas is produced during colder
sponsors, environmental consultants, site remediation
conditions, when microbial activity decreases; whereas more
professionals, environmental contractors, analytical testing
gas is produced during warmer conditions, when microbial
laboratories, data reviewers and users, and other stakeholders.
activity increases. Microorganisms responsible for gas produc-
4.10.2 This guide does not replace the need for engaging
tion are metabolically active between 4 °C and 45 °C, with an
competent persons to evaluate ebullition-facilitated NAPL/
optimal temperature range for methanogenesis between 35 °C
contaminant transport in sediments. Activities necessary to
and 42 °C (5).
develop a CSM should be conducted by persons familiar with
5.4 Ebullition generally originates from shallower
NAPL/contaminant-impacted sediment site characterization
sediments, but methanogenesis occurs anywhere in the sedi-
techniques, physical and chemical properties of NAPL/
ment column where conditions favor this process. The genera-
contaminants in sediments, fate and transport processes, reme-
tionofmethaneindeepersedimentmaynotresultinebullition,
diation technologies, and sediment evaluation protocols. The
users of this guide should consider assembling a team of
experienced project professionals with appropriate expertise to
The boldface numbers in parentheses refer to a list of references at the end of
scope,plan,andexecuteappropriatedataacquisitionactivities. this standard.
E3300 − 21
TABLE 1 Environmental Conditions Affecting Ebullition Processes
Factor Environmental Condition Effect Effect on Ebullition Rate References
Factors Affecting the Rate of Microbial Activity
Microbes (for OM
A
Microbial consortia mineralization to methane Microbial activity This is a baseline requirement for gas production. (11), (12), (13)
and carbon dioxide)
Total organic carbon
(naturally occurring,
Labile OM Microbial activity Greater labile OM content increases rate. (4), (6), (14)
anthropogenic inputs, or
both)
Anoxic redox conditions
A
This is a baseline requirement for gas production.
Presence of electron
Geochemical conditions Microbial activity Affects the stability of microbiologic processes and (1), (2)
acceptors
the composition of gas generated.
Favorable pH
Seasonal changes
Water depth (can be
Greater sediment temperatures (up to 42 °C)
Sediment temperature tidally influenced) Microbial activity (3), (4), (5), (15)
increase rates.
Sediment depth
Groundwater
Factors Affecting the Rate of Gas Bubble Nucleation, Growth, and Migration
Accretion sites (either
Availability of trapped gas on the surface
A
Gas bubble nucleation This is a baseline requirement for gas nucleation (1)
nucleation sites of solid particles or
preformed stable bubbles)
Gas concentrations
Concentrations at saturation increase rate, dilution
(including groundwater Gas bubble nucleation and growth (1), (16), (17)
Porewater conditions decreases rates.
seepage)
Salinity Gas bubble nucleation and growth Elevated salinity increases rate. (18)
Tensile strength Gas bubble growth and migration Lesser tensile strength increases rate. (8)
Grain size Gas bubble growth and migration Larger grain size increases rate. (19), (20)
Porosity Gas bubble growth and migration Greater porosity increases rate. (20)
Sediment conditions
Bulk density Gas bubble growth and migration Lesser bulk density increases rate. (20)
Cohesion Gas bubble growth and migration Lesser cohesion in sediment increases rate. (8), (19), (20)
Heterogeneity Gas bubble growth and migration Greater heterogeneity increases rate. (20)
Water depth (can be
tidally influenced)
Overburden pressure Gas bubble nucleation, growth, and migration Lesser overburden pressure increases rate. (8), (19), (21), (22)
Waterway activity
(propeller wash)
Atmospheric pressure Weather changes Gas bubble nucleation, growth, and migration Lesser atmospheric pressure increases rate. (8)
Factors Affecting the Rate of Gas Ebullition-Facilitated NAPL/Contaminant Flux
Presence of NAPL/
A
This is a baseline requirement for gas ebullition-
NAPL/contaminants contaminants in ebullition Gas ebullition-facilitated NAPL/contaminant flux (1), (23)
facilitated NAPL/contaminant flux.
active zone
A
Presence of OPAs in
This is a baseline requirement for transport of
Oil-particle aggregates Gas ebullition-facilitated NAPL/contaminant flux (9)
OPAs.
ebullition active zone
A
Baseline requirement—a factor that is required for any ebullition process to occur
E3300 − 21
due to factors that inhibit bubble nucleation, growth, or bubble formation increases with water depth and depth below
migration through the sediment into surface water. The condi- the mudline, as overburden pressure increases.
tions present at a specific site can increase or decrease the
5.4.5 Groundwaterdischargeintoawaterbodymayprovide
likelihood for ebullition to be present and include porewater
additional nutrients or contaminants that enhance or limit the
properties, sediment properties, and the overall environmental
potential for ebullition. Gas may nucleate as pressure in the
setting.Theseconditionsaresummarizedbelowandadditional
groundwater decreases as groundwater rises in the sediment
details are provided in Table 1. This table discusses effects for
column. Groundwater discharge may also impact gas compo-
asinglefactor;combinationsoffactorscanresultinsynergistic sition through the advective transport of dissolved gases, as
or antagonistic effects. well as impact ebullition rates due to changes in sediment
temperature (5.3).
5.4.1 Porewater properties including gas concentrations,
salinity, and redox chemistry can impact the rate of gas
5.5 For gas ebullition-facilitated transport (or flux) of
nucleationandgrowth,alongwiththechemicalcompositionof
NAPL/contaminantsfromsedimenttosurfacewatertooccur,it
gas generated, as further detailed in Table 1 (2), (6).
is necessary to have favorable conditions for gas bubble
5.4.2 The ability of bubbles to nucleate, grow, and migrate
formationandgrowth,thenhavethegasbubblesovercomethe
through the sediment bed is impacted by sediment properties
combined tensile strength and pressures to fracture the
including tensile strength, cohesivity, porosity, bulk density,
sediment, and finally have the gas bubbles generated in (or
grain size, and heterogeneity. Ebullition can only occur when below) a zone where the NAPL/contaminants can attach to the
the tensile strength of the sediment is exceeded by the gas
gas bubbles as the gas bubbles migrate upward through the
pressure (7). Elevated tensile strength limits the ability of gas
sediment to the water column. Due to the hydrophobic char-
bubbles to form and move upward in the sediment column. acteristics of NAPL and other organic contaminants, they
Sediment tensile strength increases with depth below the preferentially sorb to the hydrophobic bubble surface and are
transported through the sediment column to the overlying
mudline due to compression by the weight of overlying
sediment and overburden pressure from the water column. Gas surface water. NAPL that is attached to a gas bubble and is
transported to the surface of the water often spreads when the
migration in cohesive sediments is generally a result of elastic
gas bubble breaks at the water surface and forms a sheen
expansion and fracture, while in noncohesive sediments, gas
may migrate via capillary invasion, elastic expansion and blossom. Surface water sheens can subsequently break down
by photodegradation, biodegradation, volatilization, and disso-
fracture, or sediment fluidization. In noncohesive sediments,
lution of sheen constituents into the surface water, with a
preferentialpathways(duetoloweredtensilestrengthforshort
portion of the NAPL potentially resettling onto the sediment
period of time) can be developed through the process of
bed. Sheens may also be transported away from the point of
ebullition. Porosity, bulk density, sediment heterogeneity, and
release by advective and dispersive transport processes.
grain size also influence bubble nucleation, growth, and
migration, as further detailed in Table 1.
5.5.1 Similarly, surface sediments or oil-particle aggregates
(OPAs) previously deposited in the sediment bed can also be
5.4.3 Environmentalconditions,suchaschangesinpressure
transportedthroughthewatercolumnbygasbubbles.Particles
exerted on the sediment bed and the presence of groundwater
from the sediment column can sorb onto gas bubbles during
discharge, can impact the conditions needed for ebullition to
theirmigrationandbetransportedintothewatercolumn.OPAs
occur. The overburden pressure due to water depth and
form due to the aggregation of a suspended oil droplet and
atmospheric pressure directly impacts tensile strength, which
suspended particulate matter. When the solid particles adhere
can limit ebullition rates, as described in 5.4.2. There is a
to the oil droplet, the aggregates become denser than water,
relative increase in resistance to sediment fracturing in tidal
causing them to sink within the water column and deposit,
environments near the time of high tide (as compared to low
becoming part of the sediment bed. Following deposition, the
tide), as well as during flooding or other water depth changes,
OPAs may be resuspended by subsequent gas ebullition that
due to increasing water depth and overburden pressure.
entrains the OPAs (9).
Currents,vesseltraffic,andsurfacewateroutflowscanproduce
changes in pressure and periods of high shear stress during
5.6 The composition of the gas bubbles formed in the
which the cohesive strength of the sediment bed is exceeded,
ebullition process can provide information on the source(s) of
thereby increasing ebullition rates (8). Atmospheric pressure
the material undergoing methanogenesis to create the gas
also impacts tensile strength through weather conditions and
bubbles. In particular, isotopic analysis of carbon-14 ( C) can
storm events, by changing the atmospheric pressure exerted on
provide useful information about the age of the carbon source.
the overlying water and sediment bed.
If the sole carbon source is newer, more labile carbon (for
5.4.4 Additionally, the overburden and atmospheric pres-
example,plantdetritusorsewage),thegasbubbleswillcontain
sure also impact dissolved gas solubility. Increasing water
detectable concentrations of C. If the sole carbon source is
depth and associated pressure increases the solubility of
>50000yearsold(forexample,petroleumorcoaltar),the C
methane and other dissolved gases in sediment porewater,
concentrations in the gas bubbles will be non-detectable (10).
thereby increasing the dissolved concentrations that will be
Inmostsystems,therewillbeamixofnewerandoldercarbon
present at the onset of bubble nucleation. Once the greater sources that will require interpretation. Further details on the
solubility limit is reached and the porewater is saturated with
applicationof Canalysisinebullitionstudiesarepresentedin
gas, bubbles may form. This pressure-dependent limitation on Appendix X2.
E3300 − 21
6. Initial Screening for Gas Ebullition and Ebullition (daylighthours),orduringtimesofpeakboattraffic.Ebullition
Flux Measurement surveys are typically conducted over multiple days; the data
collection frequency can range from daily to weekly and may
6.1 Ebullition is a difficult process to quantify, due to its
extend over multiple seasons or tidal cycles, depending on site
stochastic and episodic nature, as well as the differing scale of
conditions.
spatial and temporal variability in response to the combined
6.3.2.2 Video surveys can be useful to remotely monitor
effects of physical, chemical, and biological factors that influ-
ebullition events and NAPLsheen.Video surveys are typically
ence gas ebullition (see Section 5). The interdependence of
conducted using a stationary camera or an unmanned aerial
these factors and associated spatial and temporal variability
vehicle (UAV). Stationary cameras are used to continuously
make it difficult to develop a predictive gas ebullition model
monitor locations already known to exhibit ebullition or sheen
from field data.
blossoms(orboth).Lowwindconditions,cloudcover,andlow
6.2 Gas ebullition occurs ubiquitously in aquatic, tidal, and
sun angle provide the quiescent conditions and minimum glare
marine environments. However, for a remedial design to
needed to produce the best results using a stationary camera.
address ebullition, it is essential to establish that gas ebullition
UAVaerialsurveysaretypicallyemployedforinitialscreening
occurs with sufficient magnitude and prevalence that it may
of a larger study area, during which the UAV is flown with a
potentially impact remedy performance, or be an important
forward camera angle of 30°–45° for better downward visibil-
contaminant transport pathway (or both of these). The main
ity to observe the water surface and the surrounding areas.
objectives of the assessment are to confirm the occurrence of
AerialflyoversurveysaremorelikelytoobserveNAPLsheens
gas ebullition, assess the intensity of ebullition events, ascer-
on the water surface than ebullition events and are useful in
tain the spatial extent of occurrence, and collect evidence of
identifying larger ebullition active areas for additional moni-
ebullition-facilitated transport of NAPL/contaminants to the
toring. Like stationary cameras, UAVs can also be used for
water column (such as sediment resuspension or visual obser-
monitoringaspecificlocationbyhoveringoverthesurveyarea
vations of sheens or NAPL on the water surface). The initial
for several minutes with the camera pointed downward. Hov-
assessment is typically performed by conducting an ebullition
ering video surveys can be useful to record ebullition events
survey using trained personnel. This may include observation
and sheen blossoms in inaccessible areas.
of gas ebullition at the surface to estimate gas ebullition rates
or underwater observation using cameras or divers. 6.3.2.3 Data collected from an ebullition survey may in-
clude the type of observation, which can be broadly catego-
6.3 Ebullition surveys are useful in establishing the occur-
rized into gas bubble only, sheen blossom (that is, gas bubble
rence of ebullition and delineating the ebullition active area to
with associated NAPL sheen), and NAPL sheen without
further refine the study area. Ebullition surveys are broadly
observable gas bubble. Other supporting data from an ebulli-
classified as surface surveys or diver-based underwater sur-
tion survey may include rate of bubbling, bubble size, surface
veys. Surface surveys include ebullition observations con-
area extent of gas bubbling, quantity of the sheening observed
ducted using trained observers or the use of video cameras to
at the surface, type of sheen, GPS coordinates, water depth,
remotely monitor ebullition events. During initial screening,
water temperature, sediment temperature, weather conditions,
surveys are typically conducted during periods when the
and boat traffic (if any). The GPS coordinates of all observa-
greatest gas ebullition rates are expected to occur, to increase
tions must be recorded. This information is useful in under-
the probability of observing ebullition and ascertain the maxi-
standing the environmental conditions contributing to
mum spatial extent of its occurrence at a site. The timing of
ebullition-facilitated NAPL/contaminant transport at a site.
peak gas ebullition occurrence varies from site to site; influ-
Care should be taken to not disturb the sediment during data
encing factors include seasonal sediment temperature changes,
collection. Multiple passes are recommended to improve the
water level fluctuation, timing of low tides, and peak boat
confidence of the observation.
trafficinnavigationalchannels.Apreliminaryunderstandingof
the site is essential for planning ebullition surveys. 6.3.3 Diver Surveys:
6.3.1 Ebullition surveys are usually conducted in a phased
6.3.3.1 Diver surveys are also performed in multiple stages,
manner, starting with a larger study area that can cover the but adequate underwater visibility is required to perform them.
entire site or a significant portion of the site. Following initial
A broad area survey is usually conducted first to identify
observations, the study area extent is refined to include only
specificareasofinterestthatcanbestudiedmorethoroughlyin
areas with ebullition occurrence.
a detailed survey (second stage). Broad area survey involves
6.3.2 Surface Surveys: establishing a grid with transect line markers and weights set
onthebottomofthewaterbody.Adiverswimsthegridfor2h
6.3.2.1 Surfacesurveyscanbeconductedfromtheshoreline
–3 h to identify the location of gas bubbles. The diver is
for well-defined or isolated gas seeps, or from a boat or kayak
equipped with a camera, and the live footage is transmitted to
inthecaseoflargerwaterbodies.Forlargesites(typically>0.5
a boat where observations are recorded. The diver can be
acres), the survey area is divided into subareas of manageable
equippedwithaGPSunittorecordthelocationofgasreleases.
size. Surveys conducted from a boat generally involve trained
Locations for the detailed survey are chosen based on results
observers traversing the observation area for an extended
durationtorecordthecharacteristicsofanebullitionevent.The from the broad area survey. The selected locations are moni-
tored periodically by a diver equipped with camera to record
duration of observations is subject to site conditions and may
range from1hto2h, before and after low tides, an entire day visual observations of gas release from the sediment.
E3300 − 21
7. Gas Ebullition Measurement (mmol/m /d). Reporting ebullition measurements in molar
units is strongly recommended, because it allows for direct
7.1 After initial screening for ebullition and identifying
comparison of ebullition measurements from different sites.
specific locations where it is occurring, it is essential to
quantify the volumetric gas release to evaluate the potential
7.4 Variability in Ebullition Measurement:
impact on remedies being considered for the site. Gas compo-
7.4.1 Several environmental conditions influence gas pro-
sition should be analyzed to ensure that it is originating from
duction rates (as discussed in Section 5) and contribute to the
the sediment and not an atmospheric source. Field gas ebulli-
uncertainty associated with measuring gas ebullition flux.
tion measurement is performed using one or more of the
These include seasonal variations induced by changes in
methods discussed in this section. This generally involves
sediment temperature, microbial activity, water depth, and
using a trapping device for capturing and measuring the gas
groundwater flow conditions; and short-term variations in-
releasedfromthesediment.Choosingtheappropriatemeasure-
duced by tidal cycle, atmospheric pressure changes, and storm
ment device is dictated by the site condition and the data
events(5.3and5.4.3).Sections7.5and7.6provideinsightson
collection objectives. Gas flux measurements can be combined
temporal and spatial variability of ebullition, as well as
with NAPL/contaminant flux measurements (as discussed in
strategies for obtaining representative gas ebullition data.
Section 8) to increase the efficiency of field investigations.
7.4.2 Field gas ebullition rates collected over a representa-
7.2 Gas measurement methods fall into two broad catego-
tive range of spatial and temporal scales provide a more
ries: direct methods and indirect methods. Direct methods
reliable estimate of the expected magnitude and range of gas
involve using a trap to collect and measure the gas released
ebullition flux at a site.
from the sediment, either at the air-surface water interface or
7.5 Temporal Variability in Ebullition Rates:
within the water column. Within the water column, the trap
may be placed suspended in the water column or close to the 7.5.1 Ingeneral,methanogenicgasproductionandreleaseis
sediment-water interface, based on site conditions and data
predominant from early spring to late fall in regions with
collection objectives. Table 2 presents different types of gas
colder climates, while it occurs throughout the year in warmer
traps, their advantages and limitations, and their application
climates. Minimal methanogenesis is reported at sediment
based on data needs. Indirect methods for gas ebullition
temperatures below 4 °C. Field gas ebullition measurements
measurement mainly involve the use of hydroacoustic surveys
should be performed during periods of expected gas ebullition
to characterize the bubble size, spatial distribution of bubbles,
occurrence,whicharesitespecific.Fieldebullitionsurveyscan
and rise velocity in the water column to estimate gas ebullition
beausefulfirststepinunderstandingtheseasonalvariabilityof
rates.This method allows for rapid scanning of large bodies of
ebullition and choosing the appropriate field measurement
water and provides good spatial and temporal resolution (24).
schedule.
7.5.2 Tounderstandtheseasonalvariability,multiplerounds
7.3 Volumetric gas ebullition measurements are typically
reported in molar units (millimoles; mmol) using the ideal gas of ebullition measurement covering different seasons and time
scales can provide short- and long-term estimates of ebullition
law. The volumetric measurements are normalized against
sampler area and deployment duration to calculate the ebulli- rates. Data collected from different seasons can be used to
tion molar flux rate in millimoles per square meter per day estimate the annual gas ebullition flux at a site.
TABLE 2 Direct Gas Measurement Methods and Application
Sampler Coverage Deployment Application Advantages Limitations
Type Area Duration
Need to be able to identify vents in
Inexpensive; rapid deployment;
sediment; small area sampled, must
Hours Detection sampling; forensic studies; simple design. Sampler can be
Cone sampler <0.2 m be placed directly on vents, and
to days risk assessment; remedial design deployed in water as shallow as
requires many samplers to represent
0.15 m in depth.
an area.
Less durable; stability depends on
surface water conditions (waves and
Sampler can be left in place for wind). Forensic studies can be
Hours Detection sampling; forensic studies;
2 2
Tent sampler 0.5 m –2 m relatively long period; can be complicated by collection of floating
to days risk assessment; remedial design
deployed in shallow water depths. sheen originating from other areas.
Requires multiple samplers to
characterize an area.
Complexity in design and field
Provides better data quality. Sampler installation; unstable on sloping
Hours Detection sampling; forensic studies;
2 2
Flux chamber 0.5 m –2 m can be left in place for relatively long surfaces. Disturbance of sediment
to days risk assessment; remedial design
period. surface. Requires multiple samplers
to characterize an area.
NAPL samples with high volatiles
Collects samples representative of
content maybe biased to high
Corral sampler/ Hours Detection sampling; forensic studies; large areas for remedial design; can
2 2
2m –60 m molecular weight constituents when
frame sampler to days risk assessment; remedial design be deployed in areas of sh
...
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