ASTM E3268-20

Standard Guide for NAPL Mobility and Migration in Sediment-Sample Collection, Field Screening, and Sample Handling

SIGNIFICANCE AND USE
4.1 Many contaminants, including chlorinated solvents and petroleum products, enter the subsurface in the form of an immiscible liquid, known as a NAPL. Understanding the potential emplacement and transport mechanism for NAPL in sediment is an important element of an overall conceptual site model (CSM) that forms a basis for (1) investigating the nature and extent of NAPL, (2) evaluating if (and how) human and ecological receptors may be exposed to NAPL, and (3) assessing remedial alternatives. In addition, demonstrating the potential movement of NAPL in sediments is hampered by the lack of standardized terminology and characterization protocols, thus necessitating this guide.  
4.1.1 Understanding the presence and movement of NAPL in sediments is complicated by the lack of standardized protocols for characterizing NAPL movement in the diverse range of sediment environments. Literature searches have indicated that there is a limited body of available, applicable research. Current research has focused on site-specific sediment NAPL mobility assessment approaches, but application of common methods or decision-making processes identified across sites were limited.  
4.1.2 The movement (or lack of movement) of NAPL in sediments is a key factor in developing protective remedial options for NAPL-impacted sediments and for the long-term management of sediment sites. Typical exposure pathways that are addressed through risk management decisions at upland sites are usually not applicable to sediment sites. Rather, “contaminants in the biologically active layer of the surface sediment at a site often drive exposure” (1)5, because in aquatic environments, benthic organisms live in the surface sediment to maintain access to oxygenated overlying water. NAPL that is present in subsurface sediment below the biologically active layer that is not migrating and has an overlying sediment that is expected to remain in place (that is, is not dredged or eroded) does not pose a risk to ...
SCOPE
1.1 This guide provides considerations to inform sample collection, field screening, and sample handling of sediments impacted with non-aqueous phase liquid (NAPL) to assist in data collection for the evaluation of NAPL movement in sediment. The conditions affecting NAPL emplacement and movement in sediments are significantly different than in upland soils. As such, the framework for the assessment of NAPL movement in upland soils has been determined to have limited applicability for sediments.  
1.2 This guide is applicable to sediment sites where the presence or suspected presence of NAPL has been identified.  
1.3 The goal of this guide is to provide a technical framework for sample collection, field screening, and sample handling activities used to evaluate NAPL conditions, in particular NAPL movement (that is, mobility at the pore scale and migration at the NAPL body scale) in sediments, which can be used to inform the development and selection of remedial options and post-remedial monitoring activities.  
1.4 This guide discusses sample collection procedures, including direct methods (that is, core and grab samples) and indirect methods (that is, DART®2, laser-induced florescence, and porewater samplers) for assessing NAPL presence or absence in sediment.  
1.5 This guide discusses field characterization procedures for assessment of NAPL-impacted sediments including visual screening, stratification assessment, shake test, ultraviolet (UV) light test, NAPL FLUTe™3, and headspace vapor monitoring.  
1.6 This guide discusses considerations to obtain samples representative of in situ conditions. This includes methods used to evaluate sediment integrity, sample retrieval from the sediment bed, core identification, sample storage onboard the vessel, sample retrieval from the coring device, sufficient sample recovery, core cutting techniques, sample removal from the core, and sample freezing/cooling considerations.  ...

General Information

• Status: Historical
• Publication Date: 14-Dec-2020
• ICS: 13.080.01 - Soil quality and pedology in general
• Technical Committee: E50 - Environmental Assessment, Risk Management and Corrective Action
• Drafting Committee: E50.04 - Corrective Action

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: E3268 − 20
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 vessel, sample retrieval from the coring device, sufficient
samplerecovery,corecuttingtechniques,sampleremovalfrom
1.1 This guide provides considerations to inform sample
the core, and sample freezing/cooling considerations.
collection, field screening, and sample handling of sediments
impacted with non-aqueous phase liquid (NAPL) to assist in 1.7 This guide discusses the objectives, approaches, and
data collection for the evaluation of NAPL movement in materials for the storage and transport of NAPL-impacted
sediment. The conditions affecting NAPL emplacement and sediment, focusing on samples taken for laboratory NAPL
movement in sediments are significantly different than in mobility and geotechnical tests. Considerations include sample
upland soils. As such, the framework for the assessment of packaging and handling, storage temperature, and hold times.
NAPL movement in upland soils has been determined to have
1.8 NAPLs such as fuels, oils, coal tar, and creosote are the
limited applicability for sediments.
primary focus of this guide.
1.2 This guide is applicable to sediment sites where the
1.9 Units—The values stated in SI or CGS units are to be
presence or suspected presence of NAPL has been identified.
regarded as the standard. No other units of measurement are
1.3 The goal of this guide is to provide a technical frame- included in this standard.
work for sample collection, field screening, and sample han-
1.10 This standard does not purport to address all of the
dling activities used to evaluate NAPLconditions, in particular
safety concerns, if any, associated with its use. It is the
NAPL movement (that is, mobility at the pore scale and
responsibility of the user of this standard to establish appro-
migration at the NAPLbody scale) in sediments, which can be
priate safety, health, and environmental practices and deter-
used to inform the development and selection of remedial
mine the applicability of regulatory limitations prior to use.
options and post-remedial monitoring activities.
1.11 This international standard was developed in accor-
dance with internationally recognized principles on standard-
1.4 This guide discusses sample collection procedures, in-
ization established in the Decision on Principles for the
cluding direct methods (that is, core and grab samples) and
®2
Development of International Standards, Guides and Recom-
indirect methods (that is, DART , laser-induced florescence,
mendations issued by the World Trade Organization Technical
and porewater samplers) for assessing NAPL presence or
Barriers to Trade (TBT) Committee.
absence in sediment.
1.5 This guide discusses field characterization procedures
2. Referenced Documents
for assessment of NAPL-impacted sediments including visual
2.1 ASTM Standards:
screening, stratification assessment, shake test, ultraviolet
D425 Test Method for Centrifuge Moisture Equivalent of
(UV) light test, NAPL FLUTe™ , and headspace vapor moni-
Soils
toring.
D854 Test Methods for Specific Gravity of Soil Solids by
1.6 This guide discusses considerations to obtain samples
Water Pycnometer
representativeof in situconditions.Thisincludesmethodsused
D1587 Practice for Thin-Walled Tube Sampling of Fine-
to evaluate sediment integrity, sample retrieval from the
Grained Soils for Geotechnical Purposes
sediment bed, core identification, sample storage onboard the
D2216 Test Methods for Laboratory Determination of Water
(Moisture) Content of Soil and Rock by Mass
ThisguideisunderthejurisdictionofASTMCommitteeE50onEnvironmental
D2487 Practice for Classification of Soils for Engineering
Assessment, Risk Management and CorrectiveAction and is the direct responsibil-
ity of Subcommittee E50.04 on Corrective Action.
Current edition approved Dec. 15, 2020. Published March 2021. DOI: 10.1520/
E3268–20 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 [e-mail]. 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 − 20
Purposes (Unified Soil Classification System) E3164 Guide for Sediment Corrective Action – Monitoring
D2488 Practice for Description and Identification of Soils E3248 Guide for NAPLMobility and Migration in Sediment
– Conceptual Models for Emplacement and Advection
(Visual-Manual Procedures)
D2937 Test Method for Density of Soil in Place by the
Drive-Cylinder Method 3. Terminology
D3213 Practices for Handling, Storing, and Preparing Soft
3.1 Definitions:
Intact Marine Soil
3.1.1 immobile NAPL, n—NAPL that does not move by
D4044 Test Method for (Field Procedure) for Instantaneous
advection within the connected void spaces of the sediment
Change in Head (Slug) Tests for Determining Hydraulic
under specified physical and chemical conditions, as may be
Properties of Aquifers
demonstrated by laboratory testing, or may be interpreted
D4104 Practice for (Analytical Procedures) Determining
based on mathematical calculations or modeling. E3248
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
D4318 Test Methods for Liquid Limit, Plastic Limit, and
anticipated field conditions. E3248
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
D5084 Test Methods for Measurement of Hydraulic Con- 3.1.4 non-aqueous phase liquid, NAPL, n—chemicals that
ductivity of Saturated Porous Materials Using a Flexible are insoluble or only slightly soluble in water that exist as a
separate liquid phase in environmental media. E3248
Wall Permeameter
D5413 Test Methods for Measurement of Water Levels in 3.1.4.1 Discussion—NAPL may be less dense than water
Open-Water Bodies (light non-aqueous phase liquid [LNAPL]) or more dense than
water (dense non-aqueous phase liquid [DNAPL]).
D5906 Guide for Measuring Horizontal Positioning During
Measurements of Surface Water Depths
3.2 Definitions of Terms Specific to This Standard:
D6151 Practice for Using Hollow-StemAugers for Geotech-
3.2.1 core catcher, n—for the purposes of this guide, a
nical Exploration and Soil Sampling
device that grips and supports the core while the sampler is
D6169 Guide for Selection of Soil and Rock Sampling
being pulled from the sediment and hoisted to the water
Devices Used With Drill Rigs for Environmental Investi-
surface. D4823
gations
3.2.2 recovery ratio, n—for the purposes of this guide, the
D6282/D6282M Guide for Direct Push Soil Sampling for
ratioA/B whereAis the distance from the top of the sediment
Environmental Site Characterizations
core to the bottom of the cutting bit and B is the distance from
D6836 Test Methods for Determination of the Soil Water
thesurfaceoftheparentdeposittothebottomofthecuttingbit.
Characteristic Curve for Desorption Using Hanging
D4823
Column, Pressure Extractor, Chilled Mirror Hygrometer,
3.2.3 undisturbed sample, n—for the purposes of this guide,
or Centrifuge
sediment particles that have not been rearranged relative to one
D6913/D6913M Test Methods for Particle-Size Distribution
another by anthropogenic activity including the collection,
(Gradation) of Soils Using Sieve Analysis
transport, and analysis of the sample. In common usage, the
D6914/D6914M Practice for Sonic Drilling for Site Charac-
term “undisturbed sample” describes particles that have been
terization and the Installation of Subsurface Monitoring
rearranged, but only to a slight degree. D4823
Devices
D7203 Practice for Screening Trichloroethylene (TCE)-
4. Significance and Use
Contaminated Media Using a Heated Diode Sensor
D7263 Test Methods for Laboratory Determination of Den-
4.1 Many contaminants, including chlorinated solvents and
sity and Unit Weight of Soil Specimens
petroleum products, enter the subsurface in the form of an
D7928 Test Method for Particle-Size Distribution (Grada-
immiscible liquid, known as a NAPL. Understanding the
tion) of Fine-Grained Soils Using the Sedimentation potential emplacement and transport mechanism for NAPL in
(Hydrometer) Analysis
sediment is an important element of an overall conceptual site
E1391 Guide for Collection, Storage, Characterization, and model (CSM) that forms a basis for (1) investigating the nature
Manipulation of Sediments for Toxicological Testing and
and extent of NAPL, (2) evaluating if (and how) human and
for Selection of Samplers Used to Collect Benthic Inver- ecological receptors may be exposed to NAPL, and (3)
tebrates
assessing remedial alternatives. In addition, demonstrating the
E3163 Guide for Selection and Application of Analytical potential movement of NAPLin sediments is hampered by the
Methods and Procedures Used during Sediment Correc- lack of standardized terminology and characterization
tive Action protocols, thus necessitating this guide.
E3268 − 20
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.
4.6.8 Section 8: Sediment Sample Handling, Storage, and
4.2.3 Thisguideisnotintendedtoprovidespecificguidance
Transport;
on sediment site investigation, risk assessment, monitoring or
4.6.9 Section 9: Field Methods for Determining Hydraulic
remedial action.
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
5. NAPL Mobility Field Investigation Overview
andregulatoryrequirements,newlydevelopedguidance,newly
published scientific research, use of alternative scientifically
5.1 Pre-Investigation Planning:
based methods and procedures, changes in regulatory criteria,
5.1.1 Pre-investigation planning and pre-sampling surveys
advances in scientific knowledge and technical capability,
should be considered to help guide sediment characterization
multiple lines of evidence approach, and unforeseen circum-
activities. Pre-investigation planning typically includes review
stances.
of fire insurance maps, manufacturing facility infastructure
maps, historical aerial photographs, and historical and current
4.4 The use of this guide is consistent with the sediment
municipal sewer records to identify areas on which to focus
risk-based corrective action (RBCA) process that guides the
future investigative efforts. Planning also should consider
researching publicly available information about the water
The boldface numbers in parentheses refer to the list of references at the end of
this standard. body, including bathymetry, tidal information, and gauging
E3268 − 20
stations. If previous sediment investigations have been com- 5.3 NAPL Emplacement Field Investigations:
pleted at the site, useful information regarding historical 5.3.1 Sedimentsamplingwithsubsequentfieldcharacteriza-
contaminant distribution, viable sample collection methods, tion and laboratory analysis is a critical component of devel-
and historical releases/source of impacts can also be obtained. oping a NAPLConceptual Model and the primary focus of this
5.1.2 Pre-sampling survey activities should include docu- guide. Guide E3248 describes the importance of supplemental
mentation of water column depth (using methods presented in field characterization data to evaluate NAPL emplacement. In
Appendix X1); the thickness of soft sediment and presence of additiontosedimentsampling,secondaryfieldcharacterization
rocks/debris (for example, by probing sediment with a pole) data typically needed to assess NAPL emplacement includes
may also be obtained. Additional information regarding the bathymetry/topography, energy of the environment, water
potentialforNAPLpresencemayalsobequalitativelyassessed quality/salinity, groundwater elevation, surface water
by identification of outfall locations, sheens on surface water, elevation, and tidal conditions. Refer to Guide E3164 for
and sheens generated from prodding sediment with a pole. guidance on secondary field data collection procedures to
These field observations may be combined with historical inform NAPL emplacement evaluations. A case study using
records to develop a sampling strategy. field investigation results to draw some preliminary conclu-
sions about the NAPL emplacement mechanism at a site is
5.2 NAPL Distribution Investigations and NAPL Movement
presented in Appendix X2.
Evaluations:
5.2.1 Sediment sample collection methodologies will 5.4 Field Assessment of Hydraulic Conditions:
evolve as the CSM is refined. A summary of typical sediment
5.4.1 Understanding the hydraulic conditions at a sediment
sample collection methodologies is included in Section 6. site is critical to select pore scale mobility test conditions and
Initial characterization typically focuses on identifying the
to inform NAPLbody scale migration evaluations. Developing
lateral and vertical distribution of NAPL. Accordingly, direct a preliminary understanding of site-wide hydraulic conditions
sediment sample collection methods that allow for logging
(includinggroundwaterandsurfacewaterelevations,hydraulic
sediment grain size and assessing NAPL presence or absence conductivity, and hydraulic gradients) is generally recom-
in the field (using visual observations or shake tests, or both)
mended during the initial phase of sediment characterization.
are often used. In addition to direct sampling collection Depending on the scale of the site, additional focused assess-
methods, indirect methods are often useful to characterize the ment of hydraulic conditions (for example, seepage, ground-
NAPL extent and distribution during initial investigations. A water exchange, and location/magnitude of upwelling) may be
site-specific evaluation of the viability of indirect methods to completed at later phases of characterization, with the goal of
improve the accuracy and efficiency of NAPL distribution informingNAPLbodyscalemigrationevaluations.Asummary
investigations should be completed prior to the full-scale of field methods to assess hydraulic conditions is included in
implementation of the field program. Section 9.
5.2.2 Once a preliminary understanding of NAPL distribu-
tion has been developed, subsequent characterization typically 6. Sediment Sample Collection Procedures
focuses on understanding NAPL body continuity, NAPL
6.1 Direct Sediment Sampling:
emplacement, and the potential for NAPL movement (that is,
6.1.1 Surface Grab Sampling Methods:
NAPL pore scale mobility potential and NAPL body scale
6.1.1.1 Although employed less frequently than core sam-
migration potential). Accordingly, methods to collect undis-
pling methods, surface grab sampling devices, such as ponar
turbed sediment samples are generally required. During NAPL
samplers, are occasionally selected to sample NAPL-impacted
movement investigations, collecting multiple samples at the
surface sediment. Identification of surface grab sampling
same interval (that is, samples from the same elevation with
devices, along with corresponding advantages and limitations,
similar stratigraphy), by offsetting multiple collocated cores
is provided in Guide E1391.
fromoneanother,maybeadvantageous.Theadvantagesofthis
6.1.2 Core Sampling Methods:
approach include assessment of NAPL continuity between
6.1.2.1 Core sampling is widely used at NAPL-impacted
adjacent cores, the ability to complete multiple pore scale
sediment sites to support characterization, including strati-
mobility tests on the same interval, and the ability to evaluate
graphic logging, laboratory testing, and NAPL movement
supplemental NAPLmobility or migration parameters, or both.
evaluations. Table 1 summarizes typical sediment coring meth-
Prior to collecting samples from multiple cores, thoughtful
ods and presents selection criteria to choose the optimal coring
planning should be completed, with particular focus on sample
method for use at a NAPL-impacted sediment site.
documentation, chain-of-custody management, and applicable
6.1.3 Core Liners:
holdtimes,aswellasthelocation,orientation,andtemperature
6.1.3.1 Incorporating core liners is required if collecting
of sample storage. As part of NAPL movement evaluations,
undisturbed samples for NAPL-impacted sediment investiga-
characterization of supplemental parameters to inform NAPL
tions or NAPL movement evaluations, or both. The core
bodyscalemigrationconditionsarealsotypicallycompletedor
methods in Table 1 either rely on a core liner as an integral part
refined, as discussed in 5.3.
of sample collection or can be modified to incorporate core
liners. Typical core liner materials include aluminum, mild
steel, stainless steel, and rigid plastic. When selecting a core
liner, consideration should be given to the compatibility of the
liner material with suspected contaminants (for example,
E3268 − 20
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 soil. soil; thin-walled samplers
hollow-stem). 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.
potential incompatibility of some types of NAPL with poly- 6.1.4 Thin-Walled Sampling Methods:
carbonate liner) and to the ease with which samples can be 6.1.4.1 Thin-walled sampling is the industry standard to
obtained from the liner. If pore scale mobility testing is collectundisturbedsamplesinuplandsites;however,obtaining
anticipated, consultation with the testing laboratory is recom- adequate recovery ratios in soft sediment with a thin-walled
mended to ensure that the liner type and diameter used are samplermaybeimpractical.Insituationswhereanundisturbed
compatible with the test apparatus. sample is necessary, thin-walled sampling should be attempted
E3268 − 20
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-
6.3.1 Collecting minimally disturbed sediment cores for the
cohesive materials (that is, sand and unconsolidated silt). Core
integrity of pore scale NAPL mobility testing (performed as
catchers that are typically used in sediment sampling are
part of a NAPL movement evaluation) is a primary focus of
identified in Guide D4823. Although core catchers aid in
this guide. Other important considerations for NAPL mobility
improving sample recovery ratios, these devices may also
sediment sampling that are shared with traditional sediment
increase core disturbance. If an undisturbed sample is required,
sampling methods are summarized in Appendix X1.
other recommendations outlined in Appendix X1 should be
attempted prior to using a core catcher. 7. Sediment Sample Field Characterization
6.2 Indirect Methods: 7.1 This section describes field characterization methods to
6.2.1 Indirect sampling methods for assessing NAPL pres- evaluate the presence of NAPL in sediment cores. These
ence or absence are typically used during the initial phase of methods provide qualitative and quantitative data on the
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 lighter PAHs). cator of NAPL; may be terpretation; potential
porewater for laboratory 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 − 20
presence of NAPL. The data can be used to make field 7.2.3.3 A positive result that is observed from a shake test
decisions on which samples to analyze and help develop a should not be interpreted as the presence of NAPL that is
CSM.
mobile at the pore scale or migrating at the NAPL body scale.
Shake tests provide no information on NAPL mobility or
7.2 Visual Observation Methods:
migration (the matrix is totally disrupted and disaggregated in
7.2.1 This section describes visual observation methods to
the testing procedure); these results only give an indication of
evaluate the presence of NAPL in sediment cores. The visual
the presence or absence of NAPL in the sediment sample.
observation results will be used primarily to understand the
7.2.4 UV Light Observation:
spatial distribution of NAPLor to select samples for laboratory
7.2.4.1 UV light observation may provide qualitative detec-
analysis, or both. It is important that all stakeholders under-
tion of NAPL in the sediment. Polycyclic aromatic hydrocar-
stand that visual observations from the following methods
bons (PAHs), which are constituents of petroleum hydrocar-
cannot be used to make a determination about NAPL mobility
bons and coal tars, will fluoresce under excitation by UV light.
or migration.
The color and intensity of fluorescence provide information on
7.2.2 Stratification Observation:
the composition and distribution of NAPLwithin the sediment.
7.2.2.1 Sediment coring, in conjunction with the identifica-
Since NAPL can be difficult to visually identify in darkly
tion of NAPL stratification, documents NAPL presence. The
colored sediments, UV light can provide information on the
location of NAPLand the NAPLcharacteristics can be used in
presence, distribution, and composition of NAPL within the
updating the CSM and evaluating NAPL mobility. Practice
sediment.ItdoesnotprovideinformationonNAPLmobilityor
D2488 presents methods for soil (and sediment) descriptions.
migration. False positives may occur, because certain minerals
Astandard method for the description of NAPLshould be used
and organic material will fluoresce at the same wavelength as
to ensure consistency among field staff and between sampling
NAPL that contains PAHs.
events. A well-defined logging procedure at the beginning of
7.2.5 NAPL FLUTe™:
the project will allow for the comparison of observations
7.2.5.1 NAPL flexible liner underground technologies
between phases of investigations. Based on the NAPL
(FLUTe™) is a color-reactive hydrophobic fabric. NAPL
stratification, samples can be selected for analysis.
wicks through the material and dissolves the dye stripes on one
7.2.3 Shake Tests:
side of the material.The NAPLcarries the dye to the back side
7.2.3.1 Sediments are often dark in color, making it difficult
of the material. The stain on the back side of the material
to observe small amounts of NAPLin the sediment, so a shake
identifies the presence of NAPL. NAPL FLUTe™ responds to
test is performed to provide qualitative information about the
various refined petroleum products and creosote.
presence or absence of NAPLin a sediment sample.The shake
7.2.5.2 NAPL FLUTe™ has been pressed against sediment
test method is based on USEPA Method 1617 (2) and the
cores to evaluate the presence of the NAPL in the core. The
Maine Department of Environmental Protection SOP TS004
result can be used to select sediment samples for laboratory
(3). An aliquot of sediment is placed in a wide-mouth bottle
testing for NAPL mobility at the pore scale and to revise the
with distilled water. The bottle is shaken to disaggregate the
CSM. However, standard procedures for the application of
sedimentmatrixandmixthesedimentandwater.Thesediment
NAPL FLUTe with sediment cores have not been developed.
is allowed to settle. The surface of the water is observed for a
separate phase. To maintain consistency in the shake tests, a
7.3 Headspace Vapor Monitoring:
standard set of descriptions should be used for the results (for
7.3.1 Headspace monitoring is performed to evaluate the
example, no sheen, trace sheen, heavy sheen, oil blebs, oil
presence of volatile organic compound vapors in sediment. In
layer). Each description should document the approximate
conjunction with other methods, the results of vapor monitor-
percentage of coverage of the surface water with NAPL.
ing may further support the presence of volatile constituents
7.2.3.2 Shaketestsprovidequalitativeinformationaboutthe
within NAPL. Headspace monitoring is described in Practice
potential presence or absence of NAPL in the sediment. Shake
D7203.
tests are typically performed to assist in field decisions on
whichsamplestosubmittothelaboratoryforporescaleNAPL
8. Sediment Sample Handling, Storage, and Transport
mobility testing or chemical analysis, or both, and which
8.1 This section describes sample handling of NAPL-
samples to archive. The shake test agitates and disaggregates
impacted sediment cores collected for geotechnical measure-
the sediment, liberating NAPLthat may not be mobile under in
ment or laboratory testing associated with NAPL movement
situconditions.Theshaketestalsomayliberatenaturalorganic
evaluations where undisturbed or minimally disturbed sample
sheen, which is not indicative of NAPL. Thus, observation of
cores are necessary for testing.
a sheen is not definitive proof of the presence of NAPL in the
sample. However, the observation of NAPL blebs or layers 8.1.1 As cited in Guide E3163, three common physical
property tests require minimally undisturbed samples: bulk
does confirm the presence of NAPLin the sample.Ashake test
result may form a layer of NAPL on the water surface density (Test Methods D2937 and D7263; (4)), porosity (Test
Methods D854; (4)) and hydraulic conductivity (Test Methods
(typically LNAPL) or coat the walls of the shake test jar
(typically DNAPL). The density of NAPL should not be D5084; (5)). Laboratory tests for capillary pressure analyses
informed by a shake test observation, but rather determined by (Test Methods D6836) and NAPL mobility (Test Method
a laboratory measurement. D425) also require minimally disturbed samples.
E3268 − 20
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
8.4 Core sample transport and storage methodologies vary,
affected by the presence of NAPL (6, 7, 8).
depending on the size and type of the cores, as well as if the
8.3.2 The results of these studies have documented a broad
cores will be frozen prior to shipment and processing. Refer to
range of responses to the NAPL-water-ice-soil distribution,
6.1 for a discussion of the different types of core samples and
ranging from minimal to no effect on the soil characteristics, to
liners; refer to 8.3 for considerations regarding freezing of the
inducing NAPL redistribution within the pore network. The
core samples.
variability in these results reflects the complex conditions
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. 2.5 ft 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
8.5.2 Sealing Ends and Core Cutting—Immediately after
structure of the sediment. For example, a 5-ft-long sediment the core is collected, the core must be cut into segments that
core with a water content of 62 % contained within a 3-in.-
remove notable void spaces and that can fit in the selected
diameter core barrel could increase in length by up to 3.2 in. shipping container. The ends of each core segment must be
upon freezing, while a similar core of upland soil with a water sealed. This should be performed in a manner that maintains
contentof18 %couldincreaseinlengthbylessthan1 in.upon the integrity of the core structure, and efforts should be made
freezing. to prevent movement of the core sample within the sleeve if
8.3.3.1 The unconsolidated nature of sediments may also momentarily placing the core in a horizontal position for this
pose difficulties for unfrozen samples, particularly in transport step.
and sample preparation, as noted in 8.5 and 8.6.Itisnot 8.5.2.1 Cut cores into lengths that will fit in the selected
uncommon for fluids to drain from core tubes after collection,
shippingcontainer.Dependingonthelinermaterialandsample
and freezing will mitigate these impacts. consistency, a saw, knife, or pipe cutter may be used to cut the
8.3.4 The freezing of NAPLmay produce chemical changes core. Rocks and other debris in the sediment may complic
...