ASTM E3281-21a

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: E3281 − 21a
Standard Guide for
NAPL Mobility and Migration in Sediments – Screening
Process to Categorize Samples for Laboratory NAPL
Mobility Testing
This standard is issued under the fixed designation E3281; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 1.5 Units—The values stated in SI or CGS units are to be
regarded as the standard. No other units of measurement are
1.1 This guide is designed for general application at a wide
included in this standard.
range of sediment sites where non-aqueous phase liquid
1.6 This standard does not purport to address all of the
(NAPL) is present or suspected to be present in the sediment.
safety concerns, if any, associated with its use. It is the
This guide describes a process to use field screening methods,
responsibility of the user of this standard to establish appro-
specifically visual observations, and the results of shake tests,
priate safety, health, and environmental practices and deter-
tocategorizetherelativeamountofNAPLpresentinasample.
mine the applicability of regulatory limitations prior to use.
This categorization can then be utilized to select co-located
1.7 This international standard was developed in accor-
sediment samples for laboratory testing to determine if the
dance with internationally recognized principles on standard-
NAPLin the sample interval is mobile or immobile at the pore
ization established in the Decision on Principles for the
scale, or any other chemical or physical testing.
Development of International Standards, Guides and Recom-
1.1.1 There is no current industry standard methodology to
mendations issued by the World Trade Organization Technical
select sediment samples for laboratory NAPLmobility testing;
Barriers to Trade (TBT) Committee.
the use of different methodologies is possible. This guide
focusesonaselectionprocessthatusesvisualobservationsand
2. Referenced Documents
shake tests. This process has the advantage of being simple to
2.1 ASTM Standards:
use and, if applied in a disciplined manner, has been demon-
D2487Practice for Classification of Soils for Engineering
strated to provide good results in the field.
Purposes (Unified Soil Classification System)
1.2 This guide is intended to inform, complement, and
D2488Practice for Description and Identification of Soils
support characterization and remedial efforts performed under
(Visual-Manual Procedures)
international, federal, state, and local environmental programs
D7203Practice for Screening Trichloroethylene (TCE)-
but not supersede local, state, federal, or international regula-
Contaminated Media Using a Heated Diode Sensor
tions. The users of this guide should review existing informa-
E2531Guide for Development of Conceptual Site Models
tion and data available for a sediment site to determine
and Remediation Strategies for Light Nonaqueous-Phase
applicableregulatoryagencyrequirementsandthemostappro-
Liquids Released to the Subsurface
priate entry point into and use of this guide.
E2856Guide for Estimation of LNAPL Transmissivity
1.3 ASTM International (ASTM) standard guides are not
E3163Guide for Selection and Application of Analytical
regulations; they are consensus standard guides that may be
Methods and Procedures Used during Sediment Correc-
followed voluntarily to support applicable regulatory require-
tive Action
ments. This guide may be used in conjunction with other
E3248GuideforNAPLMobilityandMigrationinSediment
ASTM guides developed for assessing sediment sites.
–Conceptual Models for Emplacement and Advection
E3268 Guide for NAPL Mobility and Migration in
1.4 This guide does not address methods and means of
Sediment—Sample Collection, Field Screening, and
sample collection (Guide E3163).
Sample Handling
E3282Guide for NAPL Mobility and Migration in Sedi-
ments – Evaluation Metrics
ThisguideisunderthejurisdictionofASTMCommitteeE50onEnvironmental
Assessment, Risk Management and CorrectiveAction and is the direct responsibil-
ity of Subcommittee E50.04 on Corrective Action. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Oct. 1, 2021. Published November 2021. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 2021. Last previous edition approved in 2021 as E3281–21. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/E3281–21A the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E3281 − 21a
F2534Guide for Visually Estimating Oil Spill Thickness on agencies, project sponsors, environmental consultants,
Water toxicologists, risk assessors, site remediation professionals,
environmental contractors, and other stakeholders.
3. Terminology
4.5 This guide should be used in conjunction with other
3.1 Definitions:
reference material (refer to Section 2 and References) that
3.1.1 immobile NAPL, n—NAPL that does not move by
direct the user in developing and implementing sediment
advection within the connected void spaces of the sediment
assessment programs.
under specified physical and chemical conditions, as may be
4.6 This guide is related to Guide E3163, concerning
demonstrated by laboratory testing, or may be interpreted
sedimentanalyticaltechniquesusedduringsedimentprograms.
based on mathematical calculations or modeling. E3248
This relates to Guide E3248, which discusses generic models
3.1.2 mobile NAPL, n—NAPLthat may move by advection
fortheemplacementandadvectionofNAPLinsediments.Itis
withintheconnectedvoidspacesofthesedimentunderspecific
related to Guide E3268, which describes sample collection,
physical and chemical conditions, as may be demonstrated by
field screening and sample handling considerations in NAPL
laboratory testing, or as may be interpreted based on math-
movement evaluations. And this is related to Guide E3282,
ematical calculations or modeling. E3248
which describes evaluation metrics and frameworks to deter-
mine if NAPLis immobile or immobile at the pore scale, or if
3.1.3 non-aqueous phase liquid, NAPL, n—chemicals that
are insoluble or only slightly soluble in water that exist as a it is migrating or stable at the NAPL body scale.
separate liquid phase in environmental media. E3248
4.7 This guide does not replace the need for engaging
3.1.3.1 Discussion—NAPL may be less dense than water
competent persons to evaluate NAPLemplacement and move-
(light non-aqueous phase liquid [LNAPL]) or more dense than
ment in sediments. Activities necessary to develop a concep-
water (dense non-aqueous phase liquid [DNAPL]).
tual site model should be conducted by persons familiar with
3.1.4 pore scale, n—the scale of the connected void spaces NAPL-impacted sediment site characterization techniques,
within the sediment. E3248 physical and chemical properties of NAPL in sediments, fate
and transport processes, remediation technologies, and sedi-
3.1.5 sediment(s), n—a matrix of pore water and particles
ment evaluation protocols. The users of this guide should
including gravel, sand, silt, clay, and other natural and anthro-
consider assembling a team of experienced project profession-
pogenic substances that have settled at the bottom of a tidal or
als with appropriate expertise to scope, plan, and execute
nontidal body of water. E3163
sediment NAPL data acquisition activities.
3.1.6 sheen, n—a silvery, rainbow, or dark rainbow film on
4.8 This guide provides a framework based on overarching
the surface of the sediment sample or on a water surface.
features and elements that should be customized by the user,
4. Significance and Use based on site-specific conditions, regulatory context, and
program objectives for a particular sediment site. This guide
4.1 NAPLs (for example, chlorinated solvents, petroleum
should not be used alone as a prescriptive checklist.
products, and creosote) can be emplaced in sediments through
4.9 The user of this guide should review the overall struc-
a variety of mechanisms (Guide E3248). Dense non-aqueous
ture and components of this guide before proceeding with use,
phase liquids (DNAPLs) are more dense than water, whereas
including:
light non-aqueous phase liquids (LNAPLs) are less dense than
water.
Section 1 Scope
Section 2 Referenced Documents
4.2 Standardized guidance and test methods currently exist
Section 3 Terminology
Section 4 Significance and Use
for assessing NAPL mobility at upland sites, from organiza-
Section 5 Summary of the Process for Screening and Selection of
tions such as ASTM (Guides E2531 and E2856), Interstate
Samples for Laboratory NAPL Mobility Testing
Technology & Regulatory Council (1) and the American
Section 6 Methods for Recording Visual Observations of Sheen and
NAPL in Sediment Samples
Petroleum Institute (2, 3).
Section 7 Methods for Performing Shake Testing of Sediment Samples
4.3 Guide E3248 provides guidance regarding when a
Section 8 Categorizing the Relative Presence of NAPL in Sediment
Section 9 Use of NAPL Categorization Results to Select Existing
NAPL movement evaluation is warranted. After confirming
Samples or Identify Locations and Depths for Collecting
that NAPL is present and evaluating nature and extent as
Additional Undisturbed Samples for Laboratory NAPL Mobility
appropriate, the next step in any NAPL movement evaluation Testing
Section 10 Other Methods to Select Samples for Laboratory NAPL Mobility
is to evaluate if NAPL is mobile or immobile at the pore
Testing
scale—this is done using tiered or weight of evidence (WOE)
Section 11 Keywords
approaches. This guide provides a structured process to select
Appendix X1 Recommended Procedure for Visually Characterizing Sediment
for Sheen or NAPL Observations
samples to submit to the laboratory for NAPLmobility testing
Appendix X2 Recommended Procedure for a Sediment-Water Shake Test
that is part of a NAPL movement evaluation.
Appendix X3 Case Study
References
4.4 This guide may be used by various parties involved in
sediment corrective action programs, including regulatory
5. Summary of the Process for Screening and Selection
of Samples for Laboratory NAPL Mobility Testing
5.1 One key factor that typically influences the potential for
Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof
this standard. NAPL mobility of advectively emplaced NAPL is the NAPL
E3281 − 21a
saturation (that is, the percentage of the total pore space that is 5.2.2 In the second method, whose use depends on site-
filled with NAPL); the distribution of NAPL within the pores specific conditions, the approach is to collect multiple co-
also has an effect on the mobility of the NAPL (that is, a located samples at each sample location during a single
relatively small amount in NAPL within the largest pores can sampling event. With this approach, one core is collected to
produce mobility). Generally, the potential for NAPLmobility determine the nature and extent of NAPL. Additional cores
is greater in sediments containing relatively more NAPL and fromthesamesamplinglocationarearchivedandpreservedin
less in sediments containing relatively less NAPL; for deposi- the original core liners to provide co-located samples for
tionally emplaced NAPLs, the mobility is also strongly influ- subsequent laboratory NAPL mobility testing. Once the rela-
enced by the degree of encapsulation of the NAPL. Therefore, tive amount of NAPL in various areas and depths of sediment
this guide offers a process for qualitatively categorizing the has been characterized, using the methods described in this
relative amount of NAPL present in sediments. This informa- guide, NAPL mobility sampling is performed at targeted
tion is then used to select locations and depth intervals for locations and depths in the archived co-located samples.
laboratory NAPL mobility testing.
5.2.2.1 One advantage of this approach is that laboratory
NAPL mobility test results can be obtained more quickly,
5.2 There are two ways in which the categorization process
because sample material is already available. This approach
presentedinthisguidecanbeusedtoselectlocationsanddepth
generally also has the advantage of being performed in only
intervals for laboratory NAPL mobility testing.
one mobilization.
5.2.1 In the first method, often used in sediment
investigations, grab samples of surface sediment and core 5.2.2.2 The disadvantage of this approach is that it requires
samples of subsurface sediment are collected to determine the collecting co-located samples that can be used for laboratory
natureandextentofNAPL.OncetherelativeamountofNAPL NAPL mobility testing at every sampling station during the
in various areas and depths within the sediment has been initialinvestigationofthenatureandextentofNAPL.Because
categorized using the process described in this guide, NAPL many of the co-located samples would not undergo laboratory
mobility sampling is performed at targeted locations during a testing for NAPL mobility, this approach is less efficient and
subsequent sampling event. can add considerable expense to the investigation program.
5.2.1.1 The advantage of this approach is that previously
5.3 The process for screening and selecting locations and
collected data can be used to select targeted locations and
general depths for laboratory NAPL mobility testing as pre-
general depths for laboratory NAPL mobility testing, so the
sented in this guide consists of the four major steps summa-
subsequent NAPL mobility sampling is focused and efficient.
rized in Fig. 1 and discussed in detail in 5.4. This process is
5.2.1.2 A disadvantage to this approach is that multiple
typicallyperformedinthefield,butthereisnothingprecluding
sampling events are necessary, which could extend the time
the process being applied to sediment samples elsewhere (for
required to complete the site investigation. In some cases,
example, the consultant’s office or at a laboratory).
depending on site-specific conditions (for example, difficult
access, small sampling area) and the number of cores to be 5.4 In this process, sediment samples are screened for the
collected, this approach could be more expensive than the presence of NAPL using a standardized methodology consist-
second method.
ing of visual observations (Step 1) and sediment-water shake
FIG. 1 Summary of the Process for Screening and Selection of Samples for Laboratory NAPL Mobility Testing
E3281 − 21a
testing (Step 2); the relative amount of NAPL is then catego- 5.4.4.3 Differences in mudline elevation and percent recov-
rized in Step 3; finally, decisions regarding the selection of ery should be accounted for when trying to obtain samples
from the same interval in co-located cores. Additionally, the
locations and general depths for laboratory NAPL mobility
tests are made in Step 4. Exact depths of NAPL mobility test sediment lithology should be examined to ensure that it is
comparable for the two intervals from the co-located cores.
samples are usually selected based on detailed photography of
cores collected specifically for NAPL mobility testing.
5.5 The screening process to categorize samples for labora-
5.4.1 Step 1—Avisual observation refers to the appearance
tory NAPL mobility testing provided in this guide offers the
of sheen or NAPL, if present, on and within the sediment
following benefits:
sample. Methods and standard terminology for recording
5.5.1 The use of a standard method for screening sediment
visual observations of sheen and NAPL in sediment samples
samples for the presence of NAPL reduces variability in the
are described in Section 6, and a recommended standardized
reporting of NAPL visual observation data and facilitates
visual observation procedure is provided in Appendix X1.
comparingNAPLpresenceandrelativeabundanceinsediment
across the sediment site. The use of a standard method for
5.4.2 Step 2—A sediment-water shake test is a method for
screening sediment samples for NAPL presence becomes
screening sediments for the presence of NAPL. Aliquots of
particularly important when attempting to compare and inter-
sediment and water are placed in a clear container and gently
pret NAPL observation data collected throughout multiple
shaken; the observation of sheen or NAPL is documented.
investigations or by multiple parties.
Methods for performing shake tests to confirm the presence of
5.5.2 The use of a standard shake test method to comple-
sheen or NAPLin sediment samples and standard terminology
ment visual observations increases the validity of the visual
for recording shake test results are described in Section 7,
observation data and provides a less qualitative measure of the
while a recommended standardized shake test procedure is
relativeamountofNAPLineachshake-testsamplethanvisual
provided in Appendix X2.
observations alone.
5.4.3 Step 3—Visual observations (Step 1) and shake test
5.5.3 Categorizing sediment sampling locations based on
results (Step 2) are compiled to categorize the relative amount
the relative amount of NAPL present in the sediment enables
of NAPL present in each sediment core or grab sample, from
easy identification of areas with relatively more NAPL pres-
least to most NAPL. Sediment cores/grabs are assigned NAPL
ence and relatively less NAPL presence when selecting areas
categories, ranging from Category 1 (no sheen or NAPL
forNAPLmobilitysamplingorexistingsamplesforlaboratory
presentinthesample)throughCategory4(thegreatestrelative
NAPLmobility testing. For sites with more than one sediment
NAPL presence). The process of categorizing the relative
lithologicunit,itispreferablethatthecategorizationresultsfor
presence of NAPL in sediment, based on shake test results, is
allunitsbepooled,ifpossible.However,insomecases,itmay
described in Section 8.
be necessary to separately evaluate categorization results for
5.4.4 Step 4—Based on the results of the NAPLcategoriza-
each lithological unit.
tion (Step 3), locations and general depth intervals are selected
forlaboratoryNAPLmobilitytesting.Thistestingisperformed
6. Methods for Recording Visual Observations of Sheen
eitheroncorescollectedduringasubsequenttargetedsampling
and NAPL in Sediment Samples
program (5.2.1) or from co-located cores that were previously
6.1 This section summarizes methods for systematically
collected and archived in the original core liners (5.2.2). The
describing the visible characteristics of sheen and NAPL in
use of NAPL categories to select locations and general depth
sediment and how to document those observations in a
intervals for laboratory NAPL mobility testing is discussed in
consistent manner using defined terminology.
Section 9.
6.1.1 Thebasicproceduresforvisuallycharacterizingsheen
5.4.4.1 The recommended approach is to evaluate NAPL
andNAPLinsedimentcanbeappliedtosedimentcoreorgrab
mobility across a range of NAPL conditions, with sampling
samples. A detailed methodology for visually characterizing
and testing biased towards locations and depths with relatively
and recording sheen and NAPL observations in sediment is
more NAPL(for example, Category 4), while also performing
included in Appendix X1.
some testing at locations and depths with less NAPL (for
6.1.2 These procedures are performed in addition to stan-
example, Category 3) or even sheen only (that is, Category 2).
dard core logging, which includes (but is not limited to) a
For sites with more than one major sediment lithologic unit,
description of sediment lithology, moisture content, density/
ensure that sufficient representative samples are obtained from
consistency of sediment, and color across the entire length of
each unit.
the core or sample (for guidance see Practices D2487 and
5.4.4.2 The screening process described in this guide re-
D2488).
quires disrupting the sediment matrix, so sediment that has
6.2 Visual observations of sheen and NAPL presence or
been used for visual observation of NAPL presence (for
absence, as well as the distribution of the visual observations
example, the sediment core has been split) or undergone a
within the sediment matrix, can be described using the termi-
shaketestcannotbeusedforNAPLmobilitytesting.Typically,
nology defined in Table 1.
a sediment core collected for NAPL mobility testing would
include up to several meters of intact core material for 6.3 Where sheen is observed in the sediment core or grab
submittal to the laboratory for core photography to select the
sample, the start and end depths for each unique observation
specific depth(s) of the NAPL mobility test sample(s). are recorded, and the sheen color and relative amount of sheen
E3281 − 21a
TABLE 1 Sheen and NAPL Observation Terminology
terminology provided in X1.4. When any aspect of a visual
Standard observationofsheenchanges(forexample,therelativeamount
Appearance
Terminology
observed changes), new start and end depths are recorded.
No visual No sheen or NAPL is observed.
6.3.1 Sheen color can be described using the terminology
evidence of NAPL
provided in Table X1.1, which is modified from Guide F2534.
Sheen A sheen is present, but NAPL is not observed.
6.3.2 The relative amount of sheen observed in the sample
isestimatedbycomparingtherelativesamplesurfaceareawith
Blebs Discrete droplets of NAPL are observed, but for
a sheen to standard comparison charts for visual estimates,
the most part, the sediment matrix is not visibly
contaminated or saturated. Typically, this is such as those provided in Fig. 2 (4) and selecting the
immobile NAPL.
appropriate modifier from Table X1.2.
Coated Sediment grains are coated with NAPL. There is
6.4 Where NAPL is observed in the sediment core or grab
not sufficient NAPL present to saturate the pore
sample, the start and end depths for each unique observation
spaces.
are recorded; the NAPL color, viscosity, and relative amount
Saturated The entirety of the pore space for a sample
are documented using the recommended methods and termi-
appears to be saturated with NAPL. Care should
nology provided in X1.5. When any aspect of a NAPL visual
be taken to ensure that water saturating the pore
observation changes (for example, the relative amount ob-
spaces is not misinterpreted as NAPL when using
this term (for example, use a paper towel to see if
served changes), new start and end depths are recorded.
liquid wicks like water). Depending on the NAPL
6.4.1 Relative NAPL viscosity can be described using the
viscosity, NAPL may freely drain from a sediment
sample. terminology provided in Table X1.4.
6.4.2 Similar to sheen observations, the relative amount of
NAPL observed in the sample is estimated by comparing the
observedaredocumentedusingtherecommendedmethodsand relative sample surface area covered with NAPL to standard
FIG. 2 Visual Estimate Guide
E3281 − 21a
comparison charts for visual estimates, such as those provided Section 6 and Appendix X1. Based on the visual observations,
in Fig. 2, and selecting the appropriate modifier from Table the depth at which to shake test is determined by selecting one
X1.2. or more sampling intervals with the most notable visual
presence of sheen or NAPL using the following sequence (in
6.5 After the visual appearance of sediment is described,
increasing order):
coresandgrabsamplesarephotographedforprojectdocumen-
7.2.1 silverysheen tation and later reference. Section X1.3 provides a standard
NAPL blebs < NAPL coated < NAPL saturated
method for photographing a sediment core; photographs of the
core are taken in 0.3-m to 1.0-m increments (typically, the 7.3 If sheen or NAPL is not observed, select one or more
depth intervals for shake tests based on other criteria, such as
shorter increments are used to provide more detail), with a
scale or tape measure placed next to the core/sample and changes in lithology, sediment discoloration, or elevated pho-
toionization detector (PID) readings. Due to the relatively
included in the photograph to indicate core depth. It is
recommended that photographs be taken straight on, with the small amount of sediment used when performing a shake test,
the shake test should be performed at a specific depth and not
core in the horizontal position and with the shallower depth on
the left and the deeper depth on the right. It is recommended over a wider depth interval.
7.3.1 If visual observations in a sediment core or grab
that sediment cores and grabs are photographed in a well-lit
area with natural light. sample consist of more than one visual observation type (that
is, blebs, coated, saturated, or sheen), the recommended
6.6 For quality control purposes, sheen and NAPL visual
practice is to administer one shake test from a representative
observations,aswellasthestartandenddepthsofthesevisual
sample for each visual observation type in the interval where
observations, should be double-checked for accuracy and
the most notable visual presence of sheen or NAPL for that
consistency by a second trained person.
observation type is observed (that is, one shake test in a sheen
interval with the greatest degree of sheen, one shake test in a
7. Methods for Performing Shake Testing of Sediment
NAPL bleb interval with the greatest degree of NAPL blebs,
Samples
one shake test in a NAPL-coated interval with the greatest
7.1 This section provides an overview of sediment-water
degree of NAPL coating, and one shake test in a NAPL-
shake testing, including methods for selecting sample material
saturatedintervalwiththegreatestdegreeofNAPLsaturation).
to shake test, performing the shake test, and consistently
See X2.3 for additional detailed guidance for determining
documenting the shake test results using defined terminology.
which intervals to perform shake tests on.
A sediment-water shake test is a method for screening sedi-
7.4 To perform a shake test, a consistent ratio of sediment
ments for the presence or absence of NAPL. Aliquots of
and water (see X2.4) is added to a clear container, gently
sediment and water are added to a clear container and shaken,
shaken, and allowed to equilibrate before documenting obser-
then the relative amount of sheen or NAPL is observed.
vations.Forshaketestresultstobecomparable,eachshaketest
7.1.1 Shake testing is considered an effective indicator of
must be performed in the same way using the same type of jar
NAPL presence in a sediment sample, because the NAPL that
(for example, size, shape, material, and lid), the same amounts
may be distributed in the sample, but is not observable, can
of sediment and water, the same intensity and time of shaking,
accumulate as sheens, blebs, or layers (as a direct result of the
and the same amount of time for phase separation after
sediment agitation) after the sediment matrix is disrupted.
shaking. A recommended methodology for shake testing is
While uncommon, if the NAPL present is colorless, adding a
described in detail in Appendix X2.
hydrophobic dye to the sample before the shake test may be
7.5 Todeterminetheshaketestresult,observetheshaketest
necessary.
jar sidewalls and water surface for the presence of sheen,
7.1.2 Although a shake test is a useful indicator of NAPL
NAPL blebs, or a NAPL layer. Describe the shake test results
presence and relative amount, a shake test is not a reliable
using the standard terminology in Table 2. Note that non-
indicatorofNAPLdensity;eitherLNAPLorDNAPLtypically
NAPL material (for example, organic material, ash, miscella-
formsalayerbetweentheairandwaterorcoatsthewallsofthe
neousflocculent)canfloatonthewatersurfaceoradheretothe
sample container because of interfacial tension. Shake tests
sidewalls of the shake test container, potentially confounding
also are not a reliable indicator of NAPL mobility; the
the shake test result.
observed presence of NAPL in a shake test does not provide
any evidence of whether NAPL is mobile at the pore scale in
7.6 When sheen is observed, record the sheen color using
situ.
the terminology for sheen color (Table X1.1) and estimate the
7.1.3 It is possible that shake test results may vary on a
relative amount of sheen present by comparing the relative
site-specific basis. One of the contributing factors to this could
surface area of the water surface covered with a sheen to
be the emplacement mechanism of the NAPL (for example,
standard comparison charts for visual estimates (Fig. 2).
advective versus depositional emplacement).
7.7 When shake test blebs are observed, estimate the rela-
7.1.4 A detailed procedure for conducting sediment-water
tive amount of NAPL present (that is, percent bleb coverage)
shake tests is included in Appendix X2 and summarized in 7.2
by comparing the relative surface area of the jar sidewalls and
through 7.10.
water surface covered with NAPL to standard comparison
7.2 Uponretrievalofasedimentcoreorgrabsample,visual charts for visual estimates (Fig. 2). Also, record the NAPL
observationsofsheenorNAPLaredocumentedasdescribedin color.
E3281 − 21a
TABLE 2 Shake Test Result Terminology
7.10 After the shake test result has been described and
Shake Test Result Appearance photographed, compare visual observations from the represen-
Negative No sheen or NAPL is observed. A negative shake tative sheen or NAPL observation interval to the shake test
test result indicates that sheen and NAPL are not
result. If the shake test result does not corroborate the visual
present in the sample tested.
observationsforthesampledepthinterval,checktheshaketest
Shake test sheen A sheen is present on the surface of the water,
result to confirm that the correct result was recorded. Then,
but no NAPL blebs or NAPL layer is observed. A
review the core interval and ensure that the initial visual
sheen is a silvery, rainbow, or dark rainbow film
observation was correct; update if warranted.
on the surface of water.
7.11 Confirmashaketestwasconductedeachtimeachange
Shake test blebs Discrete droplets of NAPL are present on the
sidewalls of the shake test jar, on the water’s invisualcategorization(asdefinedinTable1)wasobservedin
surface, or suspended in the water.
the sediment core or grab.
Shake test layer NAPL appears as a distinct layer within the shake
7.12 After shake test results have been checked and photo-
test jar, on the water surface. NAPL may also be
graphed and the visual observations for the corresponding
present on the sidewalls of the shake test jar.
depth interval in the sediment sample have been corroborated
against the shake test result, the shake test jar and sediment
sample can be properly discarded. New jars should be used for
subsequent shake tests.
7.8 Whenashaketestlayerisobserved,estimatetheNAPL
7.13 For quality control purposes, conduct one shake test
thickness(ifpossible)andrecordthecolor.Duetothepotential
blank per day using only water to ensure that the shake test
volume of NAPL generated in a shake test with a layer result,
container batch is not biasing results. Field duplicate shake
itmaybedifficulttoseetheNAPLlayer,becausetheshaketest
tests should be performed at a frequency of 5% to 10% of the
jar walls may be covered by NAPL.
shake tests. Field documentation of shake tests should be
7.9 After describing the shake test results, shake tests are
double-checked by a second trained person for accuracy and
photographed for project documentation and later reference
completeness.
(including shake test bleb ranking, if performed, as described
in 8.4). Section X2.5.5 provides a standard method for photo-
8. Categorizing the Relative Presence of NAPL in
graphing the shake test container without the lid from two
Sediment
angles: vertically (that is, from the top, looking down into the
shake test jar at the water surface) and horizontally (that is, 8.1 After completing the screening process described in
from the side, looking at the shake test jar in profile). Sections 6 and 7, shake test results are used to assign a NAPL
Photograph shake tests in a well-lit area, preferably with category for each sampling location (Fig. 3), based on the
natural light.To create a clear contrast between the contents of relative amount of NAPL present (Table 3). The purpose of
the shake test jar and the background, photograph the shake assigningNAPLcategoriesistoreadilyidentifyareasofmore,
test jar on a white surface with a white background. less, or no NAPL presence, to aid in the selection of locations
FIG. 3 Assigning NAPL Categories from Shake Test Results
E3281 − 21a
TABLE 3 NAPL Shake Test Categories
coverage of blebs present in the shake tests and includes a
NAPL Category Criteria check across the entire shake test dataset to confirm consis-
Category 1 Sample locations with negative shake test results, tency in the ranking. Category 3 sample locations with rela-
indicating no sheen or NAPL is present
tively more NAPL presence can then be readily distinguished
from Category 3 sample locations with relatively less NAPL
Category 2 Sample locations with shake test sheen results,
indicating the presence of sheen, but no visible
presence. As shown in Fig. 3, shake test bleb ranking is
NAPL
performed after the field investigation is complete and NAPL
categories have been assigned, so the shake test dataset can be
Category 3 Sample locations with shake test bleb results,
indicating the presence of some visible NAPL evaluated as a whole. The need to further evaluate Category 3
sample locations based on the relative amount of NAPL
Category 4 Sample locations with shake test layer results,
present should be determined on a site-specific basis. The
indicating the presence of relatively more NAPL
shake test bleb ranking process is described in 8.4.1 through
8.5.1.
8.4.1 Shake test bleb ranking will be useful if there are
and depth intervals to collect cores for laboratory NAPL
manyCategory3locationsbutnoCategory4locations(thatis,
mobility testing. These laboratory results can then be used in
shaketestingyieldsmanyshaketestblebsresults,butnoshake
frameworks to determine if the NAPL is mobile at the pore
test layer results) or if the amount of NAPL observed in
scale (see Guide E3282).
Category 3 shake tests varies significantly.
8.2 NAPL categories can be assigned on a core or grab 8.4.2 To perform shake test bleb ranking, at least two (but
sample location basis, based on the specific lithology type (for preferablythree)trainedpersonnelshouldreviewtheshaketest
example,recentdepositsvs.glacialtill),toaspecificdepth(for photographs, shake test field logs, and the sediment core or
example, surface sediment vs. subsurface sediment), or based grab sample logs for Category 3 locations to estimate the
on any other site-specific metric.
percent coverage of blebs present on the shake test water
surface and adhered to the jar walls (that is, percent bleb
8.3 In the example described in this section, NAPL catego-
coverage) to the nearest 5%. This is done using standard
ries are assigned based on the shake test result containing the
comparison charts for visual estimates, such as those provided
greatest relative amount of NAPL for a given core or grab
in Fig. 2.
sample location, so that the NAPL category represents the
8.4.2.1 Thepercentblebcoveragerecorded,whentheshake
greatest relative amount of NAPL at any depth at a given
test results were logged (see 7.6), can be used for one of the
location. When assigning a NAPL category, select the shake
three estimates.
test with the greatest relative amount of NAPL using the
8.4.2.2 When reviewing shake test photographs, note that
following sequence (in increasing order):
water in shake tests can range in appearance from clear to
8.3.1 negative shake test < shake test sheen < shake test
darkly colored or opaque, due to the composition of the shake
blebs (all ranks) < shake test layer
tested sediment (for example, organic silt, clay, sand). Organic
8.3.1.1 The NAPL categories, from least to greatest NAPL
and anthropogenic material in sediment can appear as solids
presence, are assigned as summarized in Fig. 3 and described
floating on the water in the shake test jar or adhered to shake
in Table 3.
test jar walls. Therefore, shake test photographs should be
8.3.2 Given that the relative amount of NAPL present in a
interpreted taking into consideration the sediment type, visual
shake test jar with blebs can vary significantly, Category 3
observationsofsheenorNAPLinthesedimentsampleandthe
cores/grabs can be further evaluated based on the degree of
shake test results documented on the shake test field logs.
NAPL accumulation in the shake test jar (that is, shake test
bleb ranking), from least to most NAPL. The shake test bleb 8.4.3 If all the bleb coverage estimates by the trained
ranking process is described in 8.4. personnel are within 20%, use the highest estimate to assign
8.3.3 For example, consider a core with visual observations theblebrank.Iftheblebcoverageestimatesvarybymorethan
ofnone,sheen,andNAPLsaturatedatdifferentdepthintervals, 20%, the reviewers should re-evaluate the shake test photo-
with corresponding shake test results of negative, sheen, and graphs and field information to develop consensus on the bleb
layer, respectively. The visual observation containing the coverage estimate. The consensus bleb coverage estimate is
greatest relative amount of NAPL for this core is NAPL then used to assign the shake test bleb rank.
saturated. The shake test result containing the greatest relative
8.4.4 Beforefinalizingtheshaketestblebranks,thefollow-
amountofNAPLforthiscoreistheshaketestlayer,whichwas
ing quality assurance measures should be taken to establish
associated with the NAPL saturated visual observation. The
consistency in rank estimates across the entire shake test
NAPL category for this core would be assigned based on the
dataset:
shake test layer result, which would result in this core being
8.4.4.1 Compileandcompareshaketestphotographswithin
assigned to Category 4.
each bleb rank for consistency.
8.4.4.2 Compile and compare shake test photographs be-
8.4 Depending on site-specific conditions, shake test bleb
tween bleb ranks to confirm that increasing bleb ranks consis-
rankingisrecommendedtofurtherevaluateCategory3sample
tently reflect increasing quantities of bleb coverage.
locations, based on the relative amount of NAPL present.
Shake test bleb ranking consists of using estimates of the 8.4.5 See the case study (Appendix X3) for an example of
percent bleb coverage in the shake test jar to rank the percent shake test bleb ranking.
E3281 − 21a
8.5 Depending on site-specific conditions or program 9.2.2.1 IfdifferenttypesofNAPL(thatis,differentphysical
objectives, it may be useful to develop a relationship between or chemical characteristics) are observed, sampling locations
visual observations and shake test results, to infer the relative should provide spatial coverage of each.
NAPLquantity in intervals that were not shake tested and had
9.2.3 ThemajorityofNAPLmobilitytestsamplesshouldbe
only visual observations made on them.
collected from locations where cores were collected and
8.5.1 The relationship between visual observations and
processedforbothvisualobservationsandshaketests,because
shaketestresultsshouldbeassessedonasite-specificbasis,by
the results will enable a comparison between the NAPL
reviewing the results of the visual observation and shake test
categories assigned using this guide and NAPL mobility test
screening data to confirm the presence of a consistent relation-
results.
ship.Anexampleofthesite-specificrelationshipbetweenthese
9.2.4 The screening process described in this guide requires
two screening methods is presented in the case study (Appen-
disturbingthesedimentmatrix,sothesedimentsamplethathas
dix X3).
been used for visual observations and shake testing is not
suitable for NAPL mobility testing. Typically, an intact co-
9. Use of NAPL Categorization Results to Select Existing
located sediment core collected for NAPL mobility testing
Samples or Identify Locations and Depths for
would be retained in the original core liner and would include
Collecting Additional Undisturbed Samples for
up to several meters of core material. The core would be cut
Laboratory NAPL Mobility Testing
into increments suitable for shipping and submitted to the
laboratoryforcorephotographytoselectthespecificdepthsfor
9.1 The results of the NAPL categorization discussed in
the NAPL mobility test samples.
Section8canbeusedtoselectlocationsanddepthintervalsfor
collection of undisturbed samples in a subsequent sampling
9.3 Appendix X3 presents a case study illustrating the
program, or to choose existing samples for laboratory NAPL
application of this selection process and a NAPL mobility
mobility testing; this testing will evaluate if NAPL present in
investigation and evaluation designed using the approach
the sediment sample is mobile or immobile at the pore scale.
outlined in this guide.
Objectives for laboratory NAPL mobility testing will vary
based on site-specific conditions and data needs. However, the
10. Other Methods to Select Samples for Laboratory
approach for characterizing the amount of NAPL in a sample
NAPL Mobility Testing
(which provides some indication of the potential for NAPL
10.1 Each of the technologies described in this section can
mobility) in this guide is general, suitable for a range of sites,
be used to identify NAPL presence, and the magnitude of
and adaptable to site-specific conditions and data needs.
response can be used to interpret relative amount of NAPL in
9.2 As noted in Section 5, NAPL saturation (that is, the
sediment. In general, locations and depths with the greatest
percentage of the total pore space that is filled with NAPL)
relative amount of NAPL should be preferentially targeted for
influences the potential for NAPL mobility via advection in
NAPL mobility testing.Additional NAPL mobility testing can
sediment.Generally,thepotentialforNAPLmobilityisgreater
be performed at locations and depths with less NAPLpresence
in sediments with relatively more NAPLand less in sediments
to provide NAPL mobility test results across a range of
withrelativelylessNAPL;indepositionallyemplacedNAPLs,
conditions.
the mobility is also strongly influenced by the degree of
10.2 Ultraviolet (UV) Light Screening:
encapsulation of the NAPL. Therefore, the recommended
10.2.1 Petroleum hydrocarbon, creosote, and coal tar
approach is to collect more samples for laboratory NAPL
mobility testing at locations and depths where screening has NAPLs are partially composed of individual polycyclic aro-
matic hydrocarbons (PAHs) of varying concentrations. PAHs
indicatedahigherpotentialformobileNAPL(thatis,locations
and depths with relatively more NAPL, such as Category 4 will generally fluoresce under excitation by UV light. The
intensityofthefluorescenceresponsemayprovideaqualitative
locations) and fewer samples at locations and depths with
lesser amounts of NAPL (that is, such as Category 3 and indication of the relative magnitude of NAPL in a sample but
can also vary depending upon other factors, including grain
Category 2 locations), where NAPL is more likely immobile.
Recommendations on designing a NAPL mobility sampling sizeandNAPLtype.Thecoloroffluorescencemayprovidean
indication of PAH composition (PAH mixtures principally
program to achieve these objectives are provided in 9.2.1
through 9.2.3. composed of two aromatic rings will generally appear blue
shifted, whereas mixtures principally composed of five aro-
9.2.1 It is recommended that NAPL mobility sampling
locations be biased towards areas or depths with a higher matic rings will generally appear red shifted) (5).
potential for NAPL mobility. 10.2.2 Because NAPLcan be difficult to visually identify in
9.2.2 NAPL mobility sampling locations should also pro- dark-colored sediments, field or laboratory screening of a
vide spatial coverage across areas with a higher potential for sediment core with UV light can provide useful information
mobile NAPL (for example, Category 4 areas, and if bleb regarding the presence, distribution, and primary composition
ranking is
...