ASTM E3268-21

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: E3268 − 21
Standard Guide for
NAPL Mobility and Migration in Sediment—Sample
Collection, Field Screening, and Sample Handling
This standard is issued under the fixed designation E3268; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 1.6 This guide discusses considerations to obtain samples
representativeof in situconditions.Thisincludesmethodsused
1.1 This guide provides considerations to inform sample
to evaluate sediment integrity, sample retrieval from the
collection, field screening, and sample handling of sediments
sediment bed, core identification, sample storage onboard the
impacted with non-aqueous phase liquid (NAPL) to assist in
vessel, sample retrieval from the coring device, sufficient
data collection for the evaluation of NAPL movement in
samplerecovery,corecuttingtechniques,sampleremovalfrom
sediment. The conditions affecting NAPL emplacement and
the core, and sample freezing/cooling considerations.
movement in sediments are significantly different than in
1.7 This guide discusses the objectives, approaches, and
upland soils. As such, the framework for the assessment of
materials for the storage and transport of NAPL-impacted
NAPL movement in upland soils has been determined to have
sediment, focusing on samples taken for laboratory NAPL
limited applicability for sediments.
mobility and geotechnical tests. Considerations include sample
1.2 This guide is applicable to sediment sites where the
packaging and handling, storage temperature, and hold times.
presence or suspected presence of NAPL has been identified.
1.8 NAPLs such as fuels, oils, coal tar, and creosote are the
Sediments are the subject media considered in this guide, not
primary focus of this guide.
surface water or groundwater.
1.9 Units—The values stated in SI or CGS units are to be
1.3 The goal of this guide is to provide a technical frame-
regarded as the standard. No other units of measurement are
work for sample collection, field screening, and sample han-
included in this standard.
dling activities used to evaluate NAPLconditions, in particular
1.10 This standard does not purport to address all of the
NAPL movement (that is, mobility at the pore scale and
migration at the NAPLbody scale) in sediments, which can be safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
used to inform the development and selection of remedial
priate safety, health, and environmental practices and deter-
options and post-remedial monitoring activities.
mine the applicability of regulatory limitations prior to use.
1.4 This guide discusses sample collection procedures, in-
1.11 This international standard was developed in accor-
cluding direct methods (that is, core and grab samples) and
dance with internationally recognized principles on standard-
®2
indirect methods (that is, DART , laser-induced florescence,
ization established in the Decision on Principles for the
and porewater samplers) for assessing NAPL presence or
Development of International Standards, Guides and Recom-
absence in sediment.
mendations issued by the World Trade Organization Technical
1.5 This guide discusses field characterization procedures Barriers to Trade (TBT) Committee.
for assessment of NAPL-impacted sediments including visual
2. Referenced Documents
screening, stratification assessment, shake test, ultraviolet
3 4
(UV) light test, NAPL FLUTe™ , and headspace vapor moni- 2.1 ASTM Standards:
toring.
D425 Test Method for Centrifuge Moisture Equivalent of
Soils
D854 Test Methods for Specific Gravity of Soil Solids by
Water Pycnometer
ThisguideisunderthejurisdictionofASTMCommitteeE50onEnvironmental
D1587 Practice for Thin-Walled Tube Sampling of Fine-
Assessment, Risk Management and CorrectiveAction and is the direct responsibil-
ity of Subcommittee E50.04 on Corrective Action.
Grained Soils for Geotechnical Purposes
Current edition approved July 1, 2021. Published August 2021. Originally
published in 2020. Last previous edition approved in 2020 as E3268–20. DOI:
10.1520/E3268–21 For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Trademarked by Dakota Technologies. http://www.dakotatechnologies.com/ contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
products/darts Standards volume information, refer to the standard’s Document Summary page on
Trademarked by Flexible Liner Underground Technologies. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E3268 − 21
D2216 Test Methods for Laboratory Determination of Water E3163 Guide for Selection and Application of Analytical
(Moisture) Content of Soil and Rock by Mass Methods and Procedures Used during Sediment Correc-
tive Action
D2487 Practice for Classification of Soils for Engineering
Purposes (Unified Soil Classification System) E3164 Guide for Sediment Corrective Action – Monitoring
E3248 Guide for NAPLMobility and Migration in Sediment
D2488 Practice for Description and Identification of Soils
– Conceptual Models for Emplacement and Advection
(Visual-Manual Procedures)
D2937 Test Method for Density of Soil in Place by the
3. Terminology
Drive-Cylinder Method
3.1 Definitions:
D3213 Practices for Handling, Storing, and Preparing Soft
3.1.1 immobile NAPL, n—NAPL that does not move by
Intact Marine Soil
advection within the connected void spaces of the sediment
D4044 Test Method for (Field Procedure) for Instantaneous
under specified physical and chemical conditions, as may be
Change in Head (Slug) Tests for Determining Hydraulic
demonstrated by laboratory testing, or may be interpreted
Properties of Aquifers
based on mathematical calculations or modeling. E3248
D4104 Practice for (Analytical Procedures) Determining
Transmissivity of Nonleaky Confined Aquifers by Over- 3.1.2 migrating NAPL, n—NAPL that can move at the
damped Well Response to Instantaneous Change in Head NAPL body scale, such that the NAPL body may advectively
(Slug Tests) expand in at least one direction under observed or reasonably
anticipated field conditions. E3248
D4318 Test Methods for Liquid Limit, Plastic Limit, and
Plasticity Index of Soils
3.1.3 mobile NAPL, n—NAPL that may move by advection
D4464 Test Method for Particle Size Distribution of Cata-
withintheconnectedvoidspacesofthesedimentunderspecific
lytic Materials by Laser Light Scattering
physical and chemical conditions, as may be demonstrated by
D4823 Guide for Core Sampling Submerged, Unconsoli-
laboratory testing, or as may be interpreted based on math-
dated Sediments
ematical calculations or modeling. E3248
D5073 Practice for Depth Measurement of Surface Water
3.1.4 non-aqueous phase liquid, NAPL, n—chemicals that
D5084 Test Methods for Measurement of Hydraulic Con-
are insoluble or only slightly soluble in water that exist as a
ductivity of Saturated Porous Materials Using a Flexible
separate liquid phase in environmental media. E3248
Wall Permeameter
3.1.4.1 Discussion—NAPL may be less dense than water
D5413 Test Methods for Measurement of Water Levels in
(light non-aqueous phase liquid [LNAPL]) or more dense than
Open-Water Bodies
water (dense non-aqueous phase liquid [DNAPL]).
D5906 Guide for Measuring Horizontal Positioning During
3.1.5 sediment, n—a matrix of pore water and particles
Measurements of Surface Water Depths
including gravel, sand, silt, clay, and other natural and anthro-
D6151 Practice for Using Hollow-StemAugers for Geotech-
pogenic substances that have settled at the bottom of a body of
nical Exploration and Soil Sampling
water. E3163
D6169 Guide for Selection of Soil and Rock Sampling
3.2 Definitions of Terms Specific to This Standard:
Devices Used With Drill Rigs for Environmental Investi-
3.2.1 core catcher, n—for the purposes of this guide, a
gations
device that grips and supports the core while the sampler is
D6282/D6282M Guide for Direct Push Soil Sampling for
being pulled from the sediment and hoisted to the water
Environmental Site Characterizations
surface.
D6836 Test Methods for Determination of the Soil Water
3.2.2 recovery ratio, n—for the purposes of this guide, the
Characteristic Curve for Desorption Using Hanging
Column, Pressure Extractor, Chilled Mirror Hygrometer, ratioA/B whereAis the distance from the top of the sediment
core to the bottom of the cutting bit and B is the distance from
or Centrifuge
thesurfaceoftheparentdeposittothebottomofthecuttingbit.
D6913/D6913M Test Methods for Particle-Size Distribution
(Gradation) of Soils Using Sieve Analysis
3.2.3 undisturbed sample, n—for the purposes of this guide,
D6914/D6914M Practice for Sonic Drilling for Site Charac-
sediment particles that have not been rearranged relative to one
terization and the Installation of Subsurface Monitoring
another by anthropogenic activity including the collection,
Devices
transport, and analysis of the sample. In common usage, the
D7203 Practice for Screening Trichloroethylene (TCE)-
term “undisturbed sample” describes particles that have been
Contaminated Media Using a Heated Diode Sensor
rearranged, but only to a slight degree.
D7263 Test Methods for Laboratory Determination of Den-
4. Significance and Use
sity and Unit Weight of Soil Specimens
D7928 Test Method for Particle-Size Distribution (Grada- 4.1 Many contaminants, including chlorinated solvents and
tion) of Fine-Grained Soils Using the Sedimentation
petroleum products, enter the subsurface in the form of an
(Hydrometer) Analysis immiscible liquid, known as a NAPL. Understanding the
E1391 Guide for Collection, Storage, Characterization, and
potential emplacement and transport mechanism for NAPL in
Manipulation of Sediments for Toxicological Testing and sediment is an important element of an overall conceptual site
for Selection of Samplers Used to Collect Benthic Inver- model (CSM) that forms a basis for (1) investigating the nature
tebrates and extent of NAPL, (2) evaluating if (and how) human and
E3268 − 21
ecological receptors may be exposed to NAPL, and (3) advances in scientific knowledge and technical capability,
assessing remedial alternatives. In addition, demonstrating the multiple lines of evidence approach, and unforeseen circum-
potential movement of NAPLin sediments is hampered by the stances.
lack of standardized terminology and characterization
4.4 The use of this guide is consistent with the sediment
protocols, thus necessitating this guide.
risk-based corrective action (RBCA) process that guides the
4.1.1 Understanding the presence and movement of NAPL
user to acquire and evaluate appropriate data and use each
in sediments is complicated by the lack of standardized
piece of data to refine goals, objectives, receptors, exposure
protocols for characterizing NAPL movement in the diverse
pathways, and the CSM. As the sediment RBCA process
range of sediment environments. Literature searches have
proceeds, data and conclusions reached at each tier help focus
indicated that there is a limited body of available, applicable
subsequent tiered evaluations. This integrated process results
research. Current research has focused on site-specific sedi-
in efficient, cost-effective decision-making and timely, appro-
ment NAPL mobility assessment approaches, but application
priate response actions for NAPL-impacted sediments.
of common methods or decision-making processes identified
4.5 This guide is not intended to replace or supersede
across sites were limited.
federal, state, local, or international regulatory requirements.
4.1.2 The movement (or lack of movement) of NAPL in
Users of this guide should confirm the regulatory guidance and
sediments is a key factor in developing protective remedial
requirements for the jurisdiction in which they are working.
options for NAPL-impacted sediments and for the long-term
This guide may be used to complement and support such
management of sediment sites.Typical exposure pathways that
requirements.
are addressed through risk management decisions at upland
4.5.1 This guide may be used by various parties involved at
sites are usually not applicable to sediment sites. Rather,
a sediment site, including regulatory agencies, project
“contaminants in the biologically active layer of the surface
sponsors, environmental consultants, site remediation
sedimentatasiteoftendriveexposure” (1) ,becauseinaquatic
professionals, environmental contractors, analytical testing
environments, benthic organisms live in the surface sediment
laboratories, data reviewers and users, and other stakeholders.
to maintain access to oxygenated overlying water. NAPL that
4.5.2 This guide does not replace the need for engaging
is present in subsurface sediment below the biologically active
competent persons to evaluate NAPL emplacement and move-
layer that is not migrating and has an overlying sediment that
ment in sediments.Activities described in this guide should be
isexpectedtoremaininplace(thatis,isnotdredgedoreroded)
conducted by persons familiar with NAPL-impacted sediment
does not pose a risk to human or ecological receptors, because
site characterization and remediation techniques, as well as
thereisnopathwayforexposure.Therefore,remediationofthe
sediment NAPL movement assessment protocols. The users of
NAPL may not be warranted. Thus, understanding NAPL
this guide should consider assembling a team of experienced
presence, extent and potential movement is a key factor in
project professionals with appropriate expertise to scope, plan,
managing contaminated sediment sites.
and execute sediment NAPL data acquisition activities.
4.2 This guide will aid users in developing the scope and
4.6 The user of this guide should review the overall struc-
method selection for investigating the presence and character-
ture and components of this guide before proceeding with use,
istics of NAPLin a sediment environment.This guide provides
including the following sections:
an overview of the sample collection, field screening and
4.6.1 Section 1: Scope;
sample handling methods for investigating the presence or
4.6.2 Section 2: Referenced Documents;
absence of NAPL, as well as characteristics of NAPL in the
4.6.3 Section 3: Terminology;
sediment environment.
4.6.4 Section 4: Significance and Use;
4.2.1 Use of this guide supports a multiple lines of evidence
4.6.5 Section 5: NAPL Mobility Field Investigation Over-
approach to evaluate NAPL movement in sediments.
view;
4.2.2 This guide should be used to support existing decision
4.6.6 Section 6: Sediment Sample Collection Procedures;
frameworks for field screening and sample collection for
4.6.7 Section 7: Sediment Sample Field Characterization;
NAPL-impacted sediments.
4.2.3 Thisguideisnotintendedtoprovidespecificguidance 4.6.8 Section 8: Sediment Sample Handling, Storage, and
Transport;
on sediment site investigation, risk assessment, monitoring or
remedial action. 4.6.9 Section 9: Field Methods for Determining Hydraulic
Conditions;
4.3 Assessment of NAPL movement in sediments is an
4.6.10 Section 10: Keywords;
evolving science. This guide provides a systematic, yet
4.6.11 Appendix X1: Additional Sediment Sample Collec-
flexible, decision framework to accommodate variations in
tion Considerations; and
approaches by regulatory agencies and users, based on project
4.6.12 Appendix X2: Case Study.
objectives, site complexity, unique site features, programmatic
andregulatoryrequirements,newlydevelopedguidance,newly
5. NAPL Mobility Field Investigation Overview
published scientific research, use of alternative scientifically
based methods and procedures, changes in regulatory criteria,
5.1 Pre-Investigation Planning:
5.1.1 Pre-investigation planning and pre-sampling surveys
should be considered to help guide sediment characterization
The boldface numbers in parentheses refer to the list of references at the end of
this standard. activities. Pre-investigation planning typically includes review
E3268 − 21
of fire insurance maps, manufacturing facility infastructure bodyscalemigrationconditionsarealsotypicallycompletedor
maps, historical aerial photographs, and historical and current refined, as discussed in 5.3.
municipal sewer records to identify areas on which to focus
5.3 NAPL Emplacement Field Investigations:
future investigative efforts. Planning also should consider
5.3.1 Sedimentsamplingwithsubsequentfieldcharacteriza-
researching publicly available information about the water
tion and laboratory analysis is a critical component of devel-
body, including bathymetry, tidal information, and gauging
oping a NAPLConceptual Model and the primary focus of this
stations. If previous sediment investigations have been com-
guide. Guide E3248 describes the importance of supplemental
pleted at the site, useful information regarding historical
field characterization data to evaluate NAPL emplacement. In
contaminant distribution, viable sample collection methods,
additiontosedimentsampling,secondaryfieldcharacterization
and historical releases/source of impacts can also be obtained.
data typically needed to assess NAPL emplacement includes
5.1.2 Pre-sampling survey activities should include docu-
bathymetry/topography, energy of the environment, water
mentation of water column depth (using methods presented in
quality/salinity, groundwater elevation, surface water
Appendix X1); the thickness of soft sediment and presence of
elevation, and tidal conditions. Refer to Guide E3164 for
rocks/debris (for example, by probing sediment with a pole)
guidance on secondary field data collection procedures to
may also be obtained. Additional information regarding the
inform NAPL emplacement evaluations. A case study using
potentialforNAPLpresencemayalsobequalitativelyassessed
field investigation results to draw some preliminary conclu-
by identification of outfall locations, sheens on surface water,
sions about the NAPL emplacement mechanism at a site is
and sheens generated from prodding sediment with a pole.
presented in Appendix X2.
These field observations may be combined with historical
5.4 Field Assessment of Hydraulic Conditions:
records to develop a sampling strategy.
5.4.1 Understanding the hydraulic conditions at a sediment
5.2 NAPL Distribution Investigations and NAPL Movement
site is critical to select pore scale mobility test conditions and
Evaluations:
to inform NAPLbody scale migration evaluations. Developing
5.2.1 Sediment sample collection methodologies will a preliminary understanding of site-wide hydraulic conditions
evolve as the CSM is refined. A summary of typical sediment (includinggroundwaterandsurfacewaterelevations,hydraulic
sample collection methodologies is included in Section 6. conductivity, and hydraulic gradients) is generally recom-
Initial characterization typically focuses on identifying the mended during the initial phase of sediment characterization.
lateral and vertical distribution of NAPL. Accordingly, direct Depending on the scale of the site, additional focused assess-
sediment sample collection methods that allow for logging ment of hydraulic conditions (for example, seepage, ground-
sediment grain size and assessing NAPL presence or absence water exchange, and location/magnitude of upwelling) may be
in the field (using visual observations or shake tests, or both) completed at later phases of characterization, with the goal of
are often used. In addition to direct sampling collection informingNAPLbodyscalemigrationevaluations.Asummary
methods, indirect methods are often useful to characterize the of field methods to assess hydraulic conditions is included in
NAPL extent and distribution during initial investigations. A Section 9.
site-specific evaluation of the viability of indirect methods to
6. Sediment Sample Collection Procedures
improve the accuracy and efficiency of NAPL distribution
investigations should be completed prior to the full-scale
6.1 Direct Sediment Sampling:
implementation of the field program.
6.1.1 Surface Grab Sampling Methods:
5.2.2 Once a preliminary understanding of NAPL distribu- 6.1.1.1 Although employed less frequently than core sam-
tion has been developed, subsequent characterization typically pling methods, surface grab sampling devices, such as ponar
focuses on understanding NAPL body continuity, NAPL
samplers, are occasionally selected to sample NAPL-impacted
emplacement, and the potential for NAPL movement (that is, surface sediment. Identification of surface grab sampling
NAPL pore scale mobility potential and NAPL body scale devices, along with corresponding advantages and limitations,
migration potential). Accordingly, methods to collect undis- is provided in Guide E1391.
turbed sediment samples are generally required. During NAPL 6.1.2 Core Sampling Methods:
movement investigations, collecting multiple samples at the 6.1.2.1 Core sampling is widely used at NAPL-impacted
same interval (that is, samples from the same elevation with sediment sites to support characterization, including strati-
similar stratigraphy), by offsetting multiple collocated cores graphic logging, laboratory testing, and NAPL movement
fromoneanother,maybeadvantageous.Theadvantagesofthis evaluations. Table 1 summarizes typical sediment coring meth-
approach include assessment of NAPL continuity between ods and presents selection criteria to choose the optimal coring
adjacent cores, the ability to complete multiple pore scale method for use at a NAPL-impacted sediment site.
mobility tests on the same interval, and the ability to evaluate 6.1.3 Core Liners:
supplemental NAPLmobility or migration parameters, or both. 6.1.3.1 Incorporating core liners is required if collecting
Prior to collecting samples from multiple cores, thoughtful undisturbed samples for NAPL-impacted sediment investiga-
planning should be completed, with particular focus on sample tions or NAPL movement evaluations, or both. The core
documentation, chain-of-custody management, and applicable methods in Table 1 either rely on a core liner as an integral part
holdtimes,aswellasthelocation,orientation,andtemperature of sample collection or can be modified to incorporate core
of sample storage. As part of NAPL movement evaluations, liners. Typical core liner materials include aluminum, mild
characterization of supplemental parameters to inform NAPL steel, stainless steel, and rigid plastic. When selecting a core
E3268 − 21
TABLE 1 Summary of Coring Methods
Typical Target
Coring/Sampling
Brief Description Depths into Advantages Limitations/ Difficulties Reference Standard
Method
Sediment (meters)
Punch (aka Push) Open-barrel sampler, 0–1 No mechanical equipment; Overcoming friction with Guide D4823
typically advanced with well suited for low manual extraction;
manually operated tooling accessibility areas. penetrating dense deposits
(fence post driver). (cohesive clay and sand/
gravel); water depths
greater than approximately
2m.
Piston Typically, a punch core with 0–1 Similar to punch core; Same as punch core. Guide D4823
a piston seal fixed to the however, a suspension
top of the sample interval. cable is typically attached
Occasionally incorporated to a fixed point on sample
into other methods. vessel; the use of piston
results in a vacuum to en-
hance core recovery.
Vibratory-Driven Open-barrel sampler af- 0–4 Continuous sampling of Water depths greater than Guide D4823
(also known as Vi- fixed to the weighted head. entire length in a single approximately 4 m; vibra-
bracore) High-frequency vibration of push; ability to penetrate tions may cause a realign-
the weighted head ad- soft sediment, sand, small- ment of sediment grains,
vances barrel into the sedi- diameter gravel; compara- particularly in soft sedi-
ment. Method lacks outer tively high production rates. ment; inconsistent success
casing and penetration is in penetrating dense clay.
limited to barrel length.
Sonic Drill-bit and core barrel ad- 0–25+ Capable of continuous or Vibrations may cause a Practice D6914/
vanced into the sediment intermittent sampling; suit- realignment of sediment D6914M
by a drill head that applies able for nearly all subsur- grains, particularly in soft
high-frequency vibration face materials, including sediment.
aided with direct push and rock; comparatively high
rotation. The method in- production rates; most
cludes outer casing to sonic rigs are multi-
maintain borehole integrity. functional (thin-walled
sampler, lined core-barrel
advanced via direct push,
etc.).
Thin-Walled Sampler Hollow metal tube ad- Dependent on equip- Consensus as the most Practice D1587 does not Practice D1587
®A
(Shelby Tube ) vanced into sediment via ment used to deploy. undisturbed sampling recommend use for coarse
steady pressure from drill method; suitable in fine- sand, gravel, or very hard
rig (sonic, direct push, or grained sediment. sediment; thin-walled sam-
hollow-stem). plers are typically 0.6 m
long, limiting production
rate.
Direct Push Cutting shoe and core bar- 0–15 Capable of continuous or Sample diameter typically Guide D6282/D6282M
rel with interior liner ad- intermittent sampling; able less than 7.5 cm, limiting
vanced into sediment via to penetrate most uncon- sample volume; difficulty
static pressure or impact solidated sediment; most penetrating dense deposits
hammer. Experience indi- direct push drill rigs are (cohesive clay and rock).
cates dual-tube systems multi-functional (thin-
are preferred in sediment walled sampler and vibra-
environments to maintain tory options).
borehole integrity.
Hollow-Stem Auger Cylindrical hollow tube with 0–25 Capable of continuous or Comparatively low produc- Practice D6151
with Split-Barrel helical fluting. Coupled with intermittent sampling; abil- tion rate; generally unable
Sampler split-barrel samplers ad- ity to penetrate most un- to penetrate dense clay or
vanced into the sediment consolidated sediment; rig rock; low recovery of non-
by hammering with a con- suitable for thin-walled cohesive sediment.
stant weight. Auger flights sampling.
provide outer casing to
maintain borehole integrity.
A
Trademarked by Shelby Steel Tube Company.
liner, consideration should be given to the compatibility of the obtained from the liner. If pore scale mobility testing is
liner material with suspected contaminants (for example, anticipated, consultation with the testing laboratory is recom-
potential incompatibility of some types of NAPL with poly- mended to ensure that the liner type and diameter used are
carbonate liner) and to the ease with which samples can be compatible with the test apparatus.
E3268 − 21
6.1.4 Thin-Walled Sampling Methods: increase core disturbance. If an undisturbed sample is required,
6.1.4.1 Thin-walled sampling is the industry standard to other recommendations outlined in Appendix X1 should be
collectundisturbedsamplesinuplandsites;however,obtaining attempted prior to using a core catcher.
adequate recovery ratios in soft sediment with a thin-walled
6.2 Indirect Methods:
samplermaybeimpractical.Insituationswhereanundisturbed
6.2.1 Indirect sampling methods for assessing NAPL pres-
sample is necessary, thin-walled sampling should be attempted
ence or absence are typically used during the initial phase of
to assess site-specific viability. If thin-walled sampling proves
NAPLdistribution investigations, because these tools can offer
tobeimpractical,pushmethods(punchcore,pistoncore,direct
advantages in reduced costs and increased efficiency compared
push/sonic with static pressure only) should be considered. If
to traditional sediment coring and logging. During later phases
push-based methods are shown to be impractical, the use of
of investigation, select indirect tools have also been employed
rotary or vibratory methods, or both may be required.
to semi-quantitatively estimate the magnitude (for example,
6.1.5 Non-Thin-Walled Sampling Methods:
saturation, concentration) of NAPL present, based on a well-
6.1.5.1 If non-thin-walled sampling methods are used to
developed, site-specific correlation between the output of the
collect an undisturbed core, the integrity of the core should be
tool and field observations or laboratory testing, or a combi-
evaluated, because most other methods may disturb or mix the
nation thereof. In some cases, sediment core observations and
sample during collection. Once collected, subsampling along
results from indirect methods are well-correlated. Develop-
the top, bottom, and the walls of the core should be avoided.
ment of a correlation between the indirect method and the field
Field methods used to evaluate the potential magnitude of core
observations or laboratory testing, or both may not be useful or
disturbance are outlined in Guide D6169.
practical for all sites. A summary of indirect methods is
6.1.6 Core Catchers:
included in Table 2, along with a summary of the advantages
6.1.6.1 Core catchers may be incorporated into coring
and limitations for each method.
methods to improve recovery ratios for non-thin-walled sam-
6.3 Additional Sample Collection Considerations:
pling methods. Their use is a relevant consideration in non-
cohesive materials (that is, sand and unconsolidated silt). Core 6.3.1 Collecting minimally disturbed sediment cores for the
catchers that are typically used in sediment sampling are integrity of pore scale NAPL mobility testing (performed as
identified in Guide D4823. Although core catchers aid in part of a NAPL movement evaluation) is a primary focus of
improving sample recovery ratios, these devices may also this guide. Other important considerations for NAPL mobility
TABLE 2 Summary of Indirect Methods
Typical Target
Sampling Method Brief Description Typical Constituents Advantages Limitations
Depths (meters)
Solid Phase Rod coated with solid- NAPL containing PAHs. 0–2 Capable of being deployed Rod must equilibrate
Extraction, Laser- phase extraction media, with no mechanical for hours or days
Induced onto which PAHs adsorb equipment; well-suited for before extraction;
Fluorescence for future laser-induced shoreline/marsh. analysis is performed
® A
(DART ) fluorescence (LIF) logging. at lab, delaying real-
time decisions.
Potential for
disturbance of
sediment.
Laser-Induced Logs a vertical profile of Instrument dependent. 0–15 Higher production rate; Unable to penetrate
B
Fluorescence the magnitude of target Variations of LIF are continuous logging not debris or highly dense
constituents (for example, suitable for petroleum- affected by recovery material; naturally
®C
PAHs) fluorescence that based NAPL (UVOST ), considerations; semi- fluorescing materials
coal tar/creosote-based
results from pulses of laser quantitative results allow (that is, calcite-based
®C
NAPL (TarGOST ), and
light. for correlations to other shells) may complicate
chlorinated-solvent-based
®C
parameters. interpretation of
NAPL (DyeLIF ).
results; energy
transfer problems in
fine-grained sediment;
potential for
disturbance of
sediment.
Porewater Samplers Temporary screens, diffu- NAPL composed of soluble 0–1 Elevated laboratory pore- Composite of sample
(Guide E1391) sive samplers, passive factions (for example, vola- water concentrations may interval; requires labo-
samplers, or similar tools, tile organic compounds be used as a potential indi- ratory analysis for in-
used to collect a sample of and lower molecular weight cator of NAPL; may be terpretation; potential
porewater for laboratory PAHs). used to develop a correla- for disturbance of
analysis. tion between NAPL pres- sediment.
ence and porewater con-
centrations.
A
http://www.dakotatechnologies.com/products/darts
B
https://clu-in.org/characterization/technologies/lif.cfm
C
Trademarked by Dakota Technologies.
E3268 − 21
sediment sampling that are shared with traditional sediment does confirm the presence of NAPLin the sample.Ashake test
sampling methods are summarized in Appendix X1. result may form a layer of NAPL on the water surface
(typically LNAPL) or coat the walls of the shake test jar
7. Sediment Sample Field Characterization (typically DNAPL). The density of NAPL should not be
informed by a shake test observation, but rather determined by
7.1 This section describes field characterization methods to
a laboratory measurement.
evaluate the presence of NAPL in sediment cores. These
7.2.3.3 A positive result that is observed from a shake test
methods provide qualitative and quantitative data on the
should not be interpreted as the presence of NAPL that is
presence of NAPL. The data can be used to make field
mobile at the pore scale or migrating at the NAPL body scale.
decisions on which samples to analyze and help develop a
Shake tests provide no information on NAPL mobility or
CSM.
migration (the matrix is totally disrupted and disaggregated in
7.2 Visual Observation Methods:
the testing procedure); these results only give an indication of
7.2.1 This section describes visual observation methods to
the presence or absence of NAPL in the sediment sample.
evaluate the presence of NAPL in sediment cores. The visual
7.2.4 UV Light Observation:
observation results will be used primarily to understand the
7.2.4.1 UV light observation may provide qualitative detec-
spatial distribution of NAPLor to select samples for laboratory
tion of NAPL in the sediment. Polycyclic aromatic hydrocar-
analysis, or both. It is important that all stakeholders under-
bons (PAHs), which are constituents of petroleum hydrocar-
stand that visual observations from the following methods
bons and coal tars, will fluoresce under excitation by UV light.
cannot be used to make a determination about NAPL mobility
The color and intensity of fluorescence provide information on
or migration.
the composition and distribution of NAPLwithin the sediment.
7.2.2 Stratification Observation:
Since NAPL can be difficult to visually identify in darkly
7.2.2.1 Sediment coring, in conjunction with the identifica-
colored sediments, UV light can provide information on the
tion of NAPL stratification, documents NAPL presence. The
presence, distribution, and composition of NAPL within the
location of NAPLand the NAPLcharacteristics can be used in
sediment.ItdoesnotprovideinformationonNAPLmobilityor
updating the CSM and evaluating NAPL mobility. Practice
migration. False positives may occur, because certain minerals
D2488 presents methods for soil (and sediment) descriptions.
and organic material will fluoresce at the same wavelength as
Astandard method for the description of NAPLshould be used
NAPL that contains PAHs.
to ensure consistency among field staff and between sampling
7.2.5 NAPL FLUTe™:
events. A well-defined logging procedure at the beginning of
7.2.5.1 NAPL flexible liner underground technologies
the project will allow for the comparison of observations
(FLUTe™) is a color-reactive hydrophobic fabric. NAPL
between phases of investigations. Based on the NAPL
wicks through the material and dissolves the dye stripes on one
stratification, samples can be selected for analysis.
side of the material.The NAPLcarries the dye to the back side
7.2.3 Shake Tests:
of the material. The stain on the back side of the material
7.2.3.1 Sediments are often dark in color, making it difficult
identifies the presence of NAPL. NAPL FLUTe™ responds to
to observe small amounts of NAPLin the sediment, so a shake
various refined petroleum products and creosote.
test is performed to provide qualitative information about the
7.2.5.2 NAPL FLUTe™ has been pressed against sediment
presence or absence of NAPLin a sediment sample.The shake
cores to evaluate the presence of the NAPL in the core. The
test method is based on USEPA Method 1617 (2) and the
result can be used to select sediment samples for laboratory
Maine Department of Environmental Protection SOP TS004
testing for NAPL mobility at the pore scale and to revise the
(3). An aliquot of sediment is placed in a wide-mouth bottle
CSM. However, standard procedures for the application of
with distilled water. The bottle is shaken to disaggregate the
NAPL FLUTe with sediment cores have not been developed.
sedimentmatrixandmixthesedimentandwater.Thesediment
7.3 Headspace Vapor Monitoring:
is allowed to settle. The surface of the water is observed for a
7.3.1 Headspace monitoring is performed to evaluate the
separate phase. To maintain consistency in the shake tests, a
presence of volatile organic compound vapors in sediment. In
standard set of descriptions should be used for the results (for
conjunction with other methods, the results of vapor monitor-
example, no sheen, trace sheen, heavy sheen, oil blebs, oil
ing may further support the presence of volatile constituents
layer). Each description should document the approximate
within NAPL. Headspace monitoring is described in Practice
percentage of coverage of the surface water with NAPL.
D7203.
7.2.3.2 Shaketestsprovidequalitativeinformationaboutthe
potential presence or absence of NAPL in the sediment. Shake
8. Sediment Sample Handling, Storage, and Transport
tests are typically performed to assist in field decisions on
whichsamplestosubmittothelaboratoryforporescaleNAPL 8.1 This section describes sample handling of NAPL-
mobility testing or chemical analysis, or both, and which impacted sediment cores collected for geotechnical measure-
ment or laboratory testing associated with NAPL movement
samples to archive. The shake test agitates and disaggregates
the sediment, liberating NAPLthat may not be mobile under in evaluations where undisturbed or minimally disturbed sample
cores are necessary for testing.
situconditions.Theshaketestalsomayliberatenaturalorganic
sheen, which is not indicative of NAPL. Thus, observation of 8.1.1 As cited in Guide E3163, three common physical
a sheen is not definitive proof of the presence of NAPL in the property tests require minimally undisturbed samples: bulk
sample. However, the observation of NAPL blebs or layers density (Test Methods D2937 and D7263; (4)), porosity (Test
E3268 − 21
Methods D854; (4)) and hydraulic conductivity (Test Methods uncommon for fluids to drain from core tubes after collection,
D5084; (5)). Laboratory tests for capillary pressure analyses and freezing will mitigate these impacts.
(Test Methods D6836) and NAPL mobility (Test Method
8.3.4 The freezing of NAPLmay produce chemical changes
D425) also require minimally disturbed samples.
within this phase. Although the NAPL phase will not
8.1.2 Physicalpropertytestsnotrequiringundisturbedcores
crystallize, the NAPL will increase in viscosity. For middle
include grain (particle) size distribution (gradation) of materi-
distillate and heavier hydrocarbons, paraffinic waxes may
als using sieve analysis (Test Methods D6913/D6913M and
precipitate upon cooling and freezing (9). This may not only
D4464), grain (particle) size distribution (gradation) of fine-
affect the composition of the remaining NAPL, but may also
grained materials using sedimentation (hydrometer) analysis
affect NAPL entry head pressures and mobility at the pore
(Test Method D7928), water content (Test Method D2216),
scale.
Atterberg Limits (Test Method D4318), and sediment texture
8.3.5 The respective benefits and potential impacts of freez-
classification (Practices D2487 and D2488).
ing NAPL-impacted sediments require consideration by prac-
titioners involved in sediment characterization, risk evaluation,
8.2 Whencollecting,handling,andtransportingundisturbed
and remedial programs. The practitioner must evaluate the
soil cores, it is important to consider how to maintain the pore
advantages and disadvantages of sediment freezing relative to
fluid distribution within the core, preserve the pore structure,
the objectives of the investigation.
and minimize chemical changes within the NAPL.
8.3.5.1 Where the objectives of the study require testing of
8.3 In land-based investigations, the freezing of soil cores
physical properties related to the minimally disturbed sediment
containing NAPL to ensure fluid retention and retain the
pore structure (that is, bulk density, porosity, and hydraulic
general structural integrity of the core during transport and
conductivity) or pore scale mobility of the NAPL, it should be
storage has been a common practice in the industry.
recognized that freezing may bias the results of these tests. If
8.3.1 Although the practice of freezing NAPL-containing
feasible,atrialfreeze-thawcycleshouldbeperformedwithsite
soil cores has been widespread, technical studies to determine
sediments within a core prior to processing all core samples to
the implications of the process have been limited.The majority
estimate the impact of freezing. Sample integrity can be
of investigations regarding the freezing of NAPL-impacted
evaluated visually or through imaging (for example, CT scans)
soils have focused on how these have affected the oil-water-
before and after the freeze-thaw cycle.
ice-soil interaction and how freeze-thaw conditions may be
affected by the presence of NAPL (6, 7, 8).
8.4 Core sample transport and storage methodologies vary,
8.3.2 The results of these studies have documented a broad
depending on the size and type of the cores, as well as if the
range of responses to the NAPL-water-ice-soil distribution,
cores will be frozen prior to shipment and processing. Refer to
ranging from minimal to no effect on the soil characteristics, to
6.1 for a discussion of the different types of core samples and
inducing NAPL redistribution within the pore network. The
liners; refer to 8.3 for considerations regarding freezing of the
variability in these results reflects the complex conditions
core samples.
within the NAPL-water-ice-soil mixture.
8.5 Preparation of Core Samples for Transport:
8.3.2.1 Ice formation associated with freezing is a concern,
8.5.1 Orientation—Efforts should be made to maintain the
because the formation of ice from water induces a volumetric
core in a vertical position until the core is frozen to prevent the
increase in the water phase of approximately 9 %.The increase
movement of sediment or pore fluids within the core. Cores
may disturb the sediment pore structure and influence the
thatarenotfrozenshouldbemaintainedintheverticalposition
distributionofNAPLwithinthesample.Professionaljudgment
for transport and storage.
should be used in the decision to freeze or not to freeze
8.5.1.1 Shipping Containers—Frozen cores may be shipped
sediment samples. It is recommended that a trial freezing be
horizontally in a cooler. Large plastic marine ice chests are
performed on a spare core sample in the field prior to deciding
typically used, which can contain core samples up to about
whether to freeze samples for mobility testing.
0.75 m in length. However, smaller ice chests may be adequate
8.3.3 Compared to soils, fine-grained and organic sediments
andmoreconvenientinsomecases.Unfrozencoresmaybecut
commonly have a higher water content and are more loosely
into small segments and shipped vertically in a cooler, or in
consolidated. As such, the potential effects of freezing of
larger containers designed to ship larger segments of core.
sediment cores are larger than when freezing upland soils or
Geotechnical testing laboratories frequently have recom-
sandysediments.Watercontentoffine-texturedsedimentsmay
mended designs or shipping units that they can supply to the
range from 40 % to 75 % on a wet mass basis, so a volumetric
practitioner.
increase of 9 % may produce a considerable change in the pore
structure of the sediment. For example, a 1.5 m long sediment 8.5.2 Sealing Ends and Core Cutting—Immediately after
core with a water content of 62 % contained within a 7.6 cm
the core is collected, the core must be cut into segments that
diameter core barrel could increase in length by up to 8.1 cm. remove notable void spaces and that can fit in the selected
upon freezing, while a similar core of upland soil with a water
shipping container. The ends of each core segment must be
content of 18 % could increase in length by less than 2.5 cm sealed. This should be performed in a manner that maintains
upon freezing.
the i
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