ASTM E1706-20

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: E1706 − 20
Standard Test Method for
Measuring the Toxicity of Sediment-Associated
Contaminants with Freshwater Invertebrates
This standard is issued under the fixed designation E1706; 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* 1.4 Relating Sediment Exposure to Toxicity—One of the
challenges with sediment assessment is that the toxicity of
1.1 Relevance of Sediment Contamination—Sediment pro-
sediment contaminants can vary greatly with differences in
vides habitat for many aquatic organisms and is a major
sediment characteristics; a bulk sediment concentration (nor-
repository for many of the more persistent chemicals that are
malized to dry weight) may be sufficient to cause toxicity in
introduced into surface waters. In the aquatic environment,
one sediment, while the same concentration in another sedi-
both organic and inorganic chemicals may accumulate in
ment does not cause toxicity (for example,Adams et al. 1985)
sediment, which can in turn serve as a source of exposure for
(1). Factors such as the amount and characteristics of the
organisms living on or in sediment. Contaminated sediments
organiccarbonpresentinsedimentcanalterthebioavailability
may be directly toxic to aquatic life or can be a source of
of many chemicals (Di Toro et al. 1991 (2); Ghosh 2007 (3)),
contaminants for bioaccumulation in the food chain.
as can other characteristics such as acid volatile sulfide or iron
1.2 Sediment Assessment Tools—Several types of informa-
and manganese oxides (Di Toro et al. 1990 (4), Tessier et al.
tionmaybeusefulinassessingtherisk,orpotentialrisk,posed
1996 (5)). Direct measurement of toxicity in contaminated
by sediment contaminants, including: (1) chemical analysis of
sediments can provide a means to measure the aggregate
sediment contaminants; (2) sediment toxicity tests, (3) bioac-
effects of such factors on the bioavailability of sediment
cumulation tests; and (4) surveys of benthic community
toxicants.
structure.Eachoftheseprovidesadifferenttypeofinformation
1.5 Understanding the Causes of Sediment Toxicity—While
to the assessment, and integrating information from all four
direct testing of sediment toxicity has the advantage of being
lines of evidence may often provide the most robust assess-
able to detect the effects of any toxic chemical present, it has
ments.
the disadvantage of not providing any specific indication of
1.3 Strengths of Toxicity Testing of Contaminated
what chemical or chemicals are causing the observed re-
Sediments—Directly assessing the toxicity of contaminated
sponses. Other techniques, such as spiked-sediment toxicity
sediments provides some of the same advantages to sediment
tests or Toxicity Identification Evaluation (TIE) methods for
assessment that whole effluent toxicity testing provides to
sediments have been developed and are available to help
management of industrial and municipal effluents. As for
evaluate cause/effect relationships (USEPA 2007) (6).
effluent tests, direct testing of sediment toxicity allows the
1.6 Uses of Sediment Toxicity Tests—Toxicity tests con-
assessment of biological effects even if: (1) the identities of
ducted on sediments collected from field locations can be used
toxic chemicals present are not (or not completely) known; (2)
to: (1) conduct surveys of sediment quality as measured by
the influence of site-specific characteristics of sediments on
sediment toxicity; (2) prioritize areas of sediment for more
toxicity (bioavailability) is not understood; and (3) the inter-
detailed investigation of sediment contamination; (3) deter-
activeoraggregateeffectsofmixturesofchemicalspresentare
mine the spatial extent of sediment toxicity; (4) compare the
not known or cannot be adequately predicted. In addition,
sensitivity of different organisms to sediment contamination;
testing the response of benthic or epibenthic organisms ex-
(5) evaluate the relationship between the degree of sediment
posedviasedimentprovidesanassessmentthatisbasedonthe
contamination and biological effects along a contamination
same routes of exposure that would exist in nature, rather than
gradient; (6) evaluate the suitability of sediments for removal
only through water column exposure.
andplacementatotherlocation(forexample,dredgedmaterial
disposal); (7) help establish goals for remedial actions; and (8)
This test method is under the jurisdiction of ASTM Committee E50 on
assess the effectiveness of remedial actions at reducing sedi-
Environmental Assessment, Risk Management and Corrective Action and are the
ment toxicity. These applications are generally targeted at
direct responsibility of Subcommittee E50.47 on Biological Effects and Environ-
mental Fate.
Current edition approved April 1, 2020. Published June 2020. Originally
approved in 1995. Last previous edition approved in 2010 as E1706–05(2010). Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof
DOI: 10.1520/E1706-20. this standard.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1706 − 20
assessing the likely biological effects of bedded sediments at ization established in the Decision on Principles for the
field sites at the time of sampling. However, toxicity testing of Development of International Standards, Guides and Recom-
natural or artificial sediments spiked with known quantities of mendations issued by the World Trade Organization Technical
chemicals can also be used to evaluate additional questions Barriers to Trade (TBT) Committee.
such as: (1) determining the potency of a chemical to organ-
2. Referenced Documents
isms exposed via sediment; (2) evaluating the effect of sedi-
ment composition on chemical bioavailability or toxicity; (3)
2.1 ASTM Standards:
informing chemical-specific risk assessments for chemicals
D1129Terminology Relating to Water
that may accumulate and persist in sediments upon release; (4)
D4387Guide for Selecting Grab Sampling Devices for
establishing regulatory guidance for chemicals in water or
Collecting Benthic Macroinvertebrates (Withdrawn
sediment. Spiked sediment studies have the advantage of
2003)
allowing uni-variate experiments in which exposure gradients
E11Specification forWovenWireTest Sieve Cloth andTest
canbereliablyconstructed;assuchtheylendthemselvestothe
Sieves
derivation of standardized point estimates of effect, such as a
E456Terminology Relating to Quality and Statistics
median lethal concentration (LC50) or concentration reducing
E729Guide for Conducting Acute Toxicity Tests on Test
sublethal performance by a specified amount, such as an effect
Materials with Fishes, Macroinvertebrates, and Amphib-
concentration (for example, EC20 estimated to reduce weight
ians
of test organisms by 20%).
E943Terminology Relating to Biological Effects and Envi-
ronmental Fate
1.7 Limitations—While some safety considerations are in-
E1241GuideforConductingEarlyLife-StageToxicityTests
cluded in this standard, it is beyond the scope of this standard
with Fishes
to encompass all safety requirements necessary to conduct
E1325Terminology Relating to Design of Experiments
sediment toxicity tests.
E1367TestMethodforMeasuringtheToxicityofSediment-
1.8 This standard is arranged as follows:
Associated Contaminants with Estuarine and Marine In-
Section vertebrates
Scope 1
E1383Guide for Conducting Sediment Toxicity Tests with
Referenced Documents 2
Freshwater Invertebrates (Withdrawn 1995)
Terminology 3
Summary of Test Methods 4 E1391Guide for Collection, Storage, Characterization, and
Significance and Use 5
Manipulation of Sediments for Toxicological Testing and
Interferences 6
for Selection of Samplers Used to Collect Benthic Inver-
Water, Formulated Sediments, Reagents 7
Health, Safety, Waste Management, Biosecurity 8 tebrates
Facilities, Equipment, and Supplies 9
E1525GuideforDesigningBiologicalTestswithSediments
Sample Collection, Storage, Characterization, and Spiking 10
E1688Guide for Determination of the Bioaccumulation of
Quality Assurance and Quality Control 11
Collection, Culturing, and Maintaining the Amphipod Hyalella 12
Sediment-Associated Contaminants by Benthic Inverte-
azteca and the Midge Chironomus dilutus
brates
Interpretation of Results and and Reporting 13
E1733Guide for Use of Lighting in Laboratory Testing
Precision and Bias 14
Keywords 15
E1847Practice for Statistical Analysis of Toxicity Tests
Annexes
Conducted Under ASTM Guidelines
Guidance for 10-d Sediment or Water Toxicity Tests with the Annex A1
E1850Guide for Selection of Resident Species as Test
Amphipod Hyalella azteca
Guidance for 42-d Sediment or Water Reproductive Toxicity Annex A2
Organisms for Aquatic and Sediment Toxicity Tests
Tests with the Amphipod Hyalella azteca
E2455GuideforConductingLaboratoryToxicityTestswith
Guidance for 10-d Sediment or Water Toxicity Tests with the Annex A3
Freshwater Mussels
Midge Chironomus dilutus
Guidance for Sediment or Water Life Cycle Toxicity Tests with Annex A4
E3163Guide for Selection and Application of Analytical
the Midge Chironomus dilutus
Methods and Procedures Used during Sediment Correc-
Guidance for Sediment Toxicity Tests with Juvenile Annex A5
tive Action
Freshwater Mussels
Guidance for Sediment Toxicity Tests with the Midge Annex A6
IEEE/ASTM-SI-10 Standard for Use of the International
Chironomus riparius
System of Units (SI): The Modern Metric System
Guidance for Sediment Toxicity Tests with Mayflies Annex A7
(Hexagenia spp).
3. Terminology
Guidance for Sediment Toxicity Tests with the Oligochaete Annex A8
Tubifex tubifex
3.1 Thewords“must”,“should”,“may”,“can”,and“might”
References
haveveryspecificmeaningsinthisstandard.“Must”isusedto
1.9 This standard does not purport to address all of the
express an absolute requirement, that is, to state that a test
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter- 3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
mine the applicability of regulatory limitations prior to use. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
Specific hazard statements are given in Section 8.
the ASTM website.
1.10 This international standard was developed in accor-
The last approved version of this historical standard is referenced on
dance with internationally recognized principles on standard- www.astm.org.
E1706 − 20
ought to be designed to satisfy the specified conditions, unless associated equilibrium sediment concentration in terms of the
the purpose of the test requires a different design. “Must” is principal binding phase that limits contaminant bioavailability
used only in connection with the factors that relate directly to (forexample,totalorganiccarbonfornonionicorganicsoracid
the acceptability of a test. “Should” is used to state that the volatile sulfides for metals).
specified condition is recommended and ought to be met if
3.3.8 formulated sediment, n—mixturesofmaterialsusedto
possible. Although the violation of one “should” is rarely a
mimic the physical components of a natural sediment.
serious matter, violation of several will often render the results
3.3.9 inhibition concentration (IC), n—the toxicant concen-
questionable.Termssuchas“isdesirable,”“isoftendesirable,”
tration that would cause a given percent reduction in a
and “might be desirable” are used in connection with less
non-quantalmeasurementforthetestpopulation.Forexample,
importantfactors.“May”isusedtomean“is(are)allowedto,”
the IC25 is the concentration of toxicant that would cause a
“can”isusedtomean“is(are)ableto,”and“might”isusedto
25% reduction in growth for the test population, and the IC50
mean “could possibly.” Thus, the classic distinction between
is the concentration of toxicant that would cause a 50%
“may” and “can” is preserved, and “might” is never used as a
reduction.
synonym for either “may” or “can.”
3.3.10 interstitial water or pore water, n—water occupying
3.2 Definitions—For definitions of other terms used in this
space between sediment or soil particles.
testmethod,refertoGuidesE729andE1241andTerminology
E943, E456, E1325, and D1129. For an explanation of units
3.3.11 lethal concentration (LC), n—thetoxicantconcentra-
and symbols, refer to IEEE/ASTM-SI-10 .
tion that would cause death in a given percentage of the test
population. Identical to EC when the observable adverse effect
3.3 Definitions of Terms Specific to This Standard:
isdeath.Forexample,theLC50istheconcentrationoftoxicant
3.3.1 clean, n—denotes a sediment or water that does not
that would cause death in 50% of the test population.
contain concentrations of test materials which cause apparent
stress to the test organisms or reduce their survival.
3.3.12 lowest-observable-effect concentration (LOEC),
3.3.2 clean sediment and clean water, n—denotes a sedi- n—in a toxicity test, the lowest tested concentration of a
materialatwhichorganismswereadverselyaffectedcompared
ment or water that does not contain concentrations of test
materials which cause apparent stress to the test organisms or to control organisms as determined by statistical hypothesis
tests—shouldbeaccompaniedbyadescriptionofthestatistical
reduce their survival.
tests and alternative hypotheses, levels of significance, and
3.3.3 concentration, n—theratioofweightorvolumeoftest
measures of performance, for example, survival, growth,
material(s) to the weight or volume of sediment.
reproduction, or development—and must be above any other
3.3.4 contaminated sediment, n—sediment containing
concentration not producing statistically significant adverse
chemical substances at concentrations that pose a known or
effects.
suspected threat to environmental or human health.
3.3.13 no-observable-effect concentration (NOEC), n—in a
3.3.5 control sediment, n—asedimentthatisessentiallyfree
toxicity test, the highest tested concentration of a material at
of contaminants and is used routinely to assess the acceptabil-
which organisms did as well as control organisms as deter-
ity of a test. Any contaminants in control sediment may
mined by statistical hypothesis tests—should be accompanied
originate from the global spread of pollutants and does not
by a description of the statistical tests and alternative
reflect any substantial input from local or non-point sources.
hypotheses, levels of significance, and measures of
Comparing test sediments to control sediments is a measure of
performance, for example, survival, growth, reproduction, or
the toxicity of a test sediment beyond inevitable background
development—and must be below any other concentration
contamination. Control sediment is also called a negative
producing statistically significant adverse effects.
control because no toxic effects are anticipated in this treat-
3.3.14 overlying water, n—the water placed over sediment
ment.
in a test chamber during a test.
3.3.6 effect concentration (EC), n—the toxicant concentra-
3.3.15 reference sediment, n—a whole sediment near an
tionthatwouldcauseaneffectinagivenpercent-ageofthetest
areaofconcernusedtoassesssedimentconditionsexclusiveof
population. Identical to lethal concentration (LC) when the
material(s) of interest. The reference sediment may be used as
observable adverse effect is death. For example, the EC50 is
an indicator of localized sediment conditions exclusive of the
theconcentrationoftoxicantthatwouldcauseaspecifiedeffect
specific pollutant input of concern. Such sediment would be
in 50% of the test population.
collected near the site of concern and would represent the
3.3.7 equilibrium partitioning sediment guidelines (ESGs),
background conditions resulting from any localized pollutant
n—numericalconcentrationsofchemicalcontaminantsinsedi-
inputs as well as global pollutant input. This is the manner in
ment at or below which direct lethal or sublethal toxic effects
which reference sediment is used in dredge material evalua-
on benthic organisms are not expected. ESGs are based on the
tions.
theory that an equilibria exists among contaminant concentra-
tion in sediment pore water, contaminant associated with a 3.3.16 reference-toxicity test, n—a test conducted with
binding phase in sediment, and biota. ESGs are derived by reagent-gradereferencechemicaltoassessthesensitivityofthe
assigning a protective water-only effects concentration to the testorganisms.Deviationsoutsideanestablishednormalrange
pore water (such as a Final ChronicValue), and expressing the may indicate a change in the sensitivity of the test organism
E1706 − 20
population. Reference-toxicity tests are most often performed number of young/surviving female, and survival-normalized
in the absence of sediment. reproduction). Procedures are primarily described for testing
freshwater sediments; however, estuarine sediments (up to 15
3.3.17 sediment, n—particulate material that usually lies
‰ salinity) can also be tested in long-term toxicity tests with
belowwater.Formulatedparticulatematerialthatisintendedto
H. azteca.Thelonger-termmethodwith H. aztecaalsoinclude
lie below water in a test.
options for abbreviated versions of this test (for example, 28-d
3.3.18 spiked sediment, n—a sediment to which a material
exposures measuring survival, dry weight, and biomass).Also
has been added for experimental purposes.
included is guidance on adapting this method for use in testing
3.3.19 whole sediment, n—sediment and associated pore
the toxicity of chemicals introduced via the water column
water which have had minimal manipulation. The term bulk
rather than sediment.
sediment has been used synonymously with whole sediment.
4.4 Short-term Toxicity Testing with the Midge Chironomus
dilutus—Short-term10-dsedimenttoxicitytestingmethodsare
4. Summary of Test Method
outlined the midge Chironomus dilutus in Annex A2. The
4.1 Method Description—Procedures are described for test-
short-term sediment exposures with C. dilutus are started with
ing freshwater organisms in the laboratory to evaluate the
known-age organisms. Toxicity tests are conducted for 10 d in
potential toxicity of chemicals associated with whole sedi-
300-mLchamberscontaining100mLofsedimentand175mL
ments or with water-borne exposures to contamiants. Sedi-
of overlying water. Overlying water is renewed daily and
ments may be collected from the field or spiked with com-
chemistry of the overlying water is monitored. Food is pro-
pounds in the laboratory. This standard is a companion to the
vided daily. The endpoints in the 10-d toxicity test with C.
USEPA(2019) (7) methods manual and both this standard and
dilutus are survival, ash-free dry weight, and biomass. Also
USEPA (2019) (7) were developed as revisions to the second
included is guidance on adapting this method for use in testing
edition of the USEPA (2000) (8) methods manual and a
the toxicity of chemicals introduced via the water column
previousversionofthisstandard(TestMethodE1706-19).This
rather than sediment.
standard and USEPA(2019) (7) have lead to the development
of other methods for assessing sediment toxicity with inverte-
4.5 Long-term Toxicity Testing with the Midge Chironomus
brates by other organizations (that is, Enviroment Canada
dilutus—Methodsaredescribedforconductinglong-termsedi-
1997ab (9, 10), 2007 (11), 2013 (12), 2017 (13); OECD 2004a
ment toxicity tests with C. dilutus in AnnexA4. Midge larvae
and b (14, 15), 2006 (16), 2010 (17); ISO 2013 (18); Test
are exposed to sediments beginning at 3 d old. After 14 d of
Method E1367).
exposure, a subset of replicates are destructively sampled to
4.2 Short-term Toxicity Testing with the Amphipod Hyalella determine larval survival, ash-free-dry weight, and biomass.
azteca—Short-term 10-d sediment toxicity testing methods are
The remaining reproduction replicates are continued through
outlined for the amphipod Hyalella azteca in Annex A1. The emergence and reproduction of adult midges (for up to about
short-term sediment exposures with H. azteca are started with
50 days in exposure started with about 3-d-old larvae), ending
known-age organisms. Toxicity tests are conducted for 10 d in
when no additional adult emergence has been recorded for 7
300-mLchamberscontaining100mLofsedimentand175mL
consecutive days. Overlying water is renewed daily and
of overlying water. Overlying water is renewed daily and
chemistry of the overlying water is monitored. Food is pro-
chemistry of the overlying water is monitored. Food is pro-
vided daily. Endpoints are larval survival, larval weight, larval
vided daily. The endpoints in the 10-d toxicity test with H.
biomass, percent adult emergence, time to adult emergence,
azteca are survival, dry weight, and biomass. Procedures are
number of egg masses per mated female, average eggs per egg
primarily described for testing freshwater sediments; however,
mass, percent of eggs hatching, total young produced, and
estuarine sediments (up to 15 ‰ salinity) can also be tested in
survival-normalized reproduction. The longer-term method
10-dtoxicitytestswith H. azteca.Alsoincludedisguidanceon
with C. dilutusalsoincludeoptionsforabbreviatedversionsof
adaptingthismethodforuseintestingthetoxicityofchemicals
this test (for example, measuring survival, weight, biomass of
introduced via the water column rather than sediment.
larvae and emergence of adults but not measuring reproduc-
tion). Also included is guidance on adapting this method for
4.3 Long-term Toxicity Testing with the Amphipod Hyalella
useintestingthetoxicityofchemicalsintroducedviathewater
azteca—Methods are described for conducting long-term sedi-
column rather than sediment.
ment toxicity tests with H. azteca in AnnexA2. Toxicity tests
are conducted in 300-mL chambers containing 100 mL of
4.6 Additional Species for Sediment Toxicity Testing—
sediment and 175 mL of overlying water. Overlying water is
Guidance is also provided for conducting sediment toxicity
renewed daily and chemistry of the overlying water is moni-
tests with juvenile freshwater mussels (Annex A5), with a
tored. Food is provided daily. The long-term sediment expo-
second species of midge (Chironomus riparius, Annex A6),
sures with H. azteca are started with known-age 7- to 8-d-old
with a mayfly (Hexagenia spp., Annex A7), and with an
amphipods. On Day 28, amphipods are isolated from the
oligochaete (Tubifex tubifex, Annex A8).
sediment and placed in water-only chambers where reproduc-
4.7 Bioaccumulation Testing with Sediment—Guidance for
tion is measured on Day 35 and 42. Endpoints measured in the
long-termamphipodtestincludesurvival(Day28,35,and42), conducting 28-d sediment bioaccumulation tests with the
dry weight and biomass (Day 28 and 42), reproduction oligochaete Lumbriculus variegatus is provided in Guide
(number of young per female produced from Day 28 to 42, E1688 and in USEPA (2019) (7).
E1706 − 20
4.8 The previous version of this standard (Test Method primary criteria used for selecting H. azteca, C. dilutus, C.
E1706-19) described methods for conducting whole-sediment riparius, Hexageniassp., T. tubifex,andfreshwatermusselsfor
toxicity tests with Daphnia magna and Ceriodaphnia dubia sediment toxicity testing (USEPA 2000 (8), Test Method
(cladocerans)andwith Diporeiaspp.(amphipod).Methodsfor E1706-19, Guide E1525, Guide E2455).
conducting sediment toxicity tests with cladocerans and with
Diporeia spp. are not included in the current version of the 5. Significance and Use
standard due to limited use of these methods over the past 25
5.1 Sediment provides habitat for many aquatic organisms
years. A description of the methods for conducting sediment
and is a major repository for many of the more persistent
toxicitytestswith D. magna, C. dubiaand Diporeiaspp.canbe
chemicals that are introduced into surface waters. In the
found in a historic version of the standard (E1706-19) at
aquatic environment, most anthropogenic chemicals and waste
http://www.astm.org.
materials including toxic organic and inorganic chemicals can
4.9 Results of toxicity tests, even those with the same
accumulate in sediment, which can in turn serve as a source of
species,usingproceduresdifferentfromthosedescribedinthis
exposurefororganismslivingonorinsediment.Contaminated
standard may not be comparable and using these different
sediments may be directly toxic to aquatic life or can be a
procedures may alter bioavailability (Guide E1525). Compari-
source of contaminants for bioaccumulation in the food chain.
son of results obtained using modified versions of these
5.2 Theobjectiveofasedimenttestistodeterminewhether
procedures might provide useful information concerning new
chemicalsinsedimentareharmfultoorarebioaccumulatedby
concepts and procedures for conducting sediment tests with
benthicorganisms.Thetestscanbeusedtomeasureinteractive
aquatic organisms. If toxicity tests are conducted with proce-
toxic effects of complex chemical mixtures in sediment.
dures different from those described in this test method,
Furthermore, knowledge of specific pathways of interactions
additional tests are required to determine comparability of
among sediments and test organisms is not necessary to
results.Generalproceduresdescribedinthisstandardmightbe
conduct the tests. Sediment tests can be used to: (1) determine
useful for conducting tests with other aquatic organisms;
the relationship between toxic effects and bioavailability, (2)
however, modifications may be necessary (Guide E1850).
investigate interactions among chemicals, (3) compare the
4.10 Selection of Test Organisms—A previous version of
sensitivities of different organisms, (4) determine spatial and
this standard (Test Method E1706-19), Guide E1525, and
temporal distribution of contamination, (5) evaluate hazards of
USEPA(2000) (8) provide information that was used to select
dredged material, (6) measure toxicity as part of product
the test organisms in Annex A1 to Annex A8 for conducting
licensing or safety testing, (7) rank areas for clean up, and (8)
sediment toxicity testing.
estimate the effectiveness of remediation or management
4.10.1 Thechoiceofasedimenttoxicitytestorganismhasa
practices.
majorinfluenceontherelevance,success,andinterpretationof
5.3 Results of toxicity tests on sediments spiked at different
a test. Test organism selection should be based on both
concentrations of chemicals can be used to establish cause and
environmentalrelevanceandpracticalconcerns(GuideE1525,
effect relationships between chemicals and biological re-
E1850). Ideally, a test organism should: (1) have a toxicologi-
sponses.Resultsoftoxicitytestswithtestmaterialsspikedinto
cal database demonstrating relative sensitivity and discrimina-
sediments at different concentrations may be reported in terms
tion to a range of chemicals of concern in sediment; (2) have
of a LC50 (median lethal concentration), an EC50 (median
a database for inter-laboratory comparisons of procedures (for
effect concentration), an IC50 (inhibition concentration), or as
example, round-robin studies); (3) be in contact with sediment
a NOEC (no observed effect concentration) or LOEC (lowest
(for example, water column vs. benthic organism); (4)be
observedeffectconcentration).However,spikedsedimentmay
readilyavailablethroughcultureorfromfieldcollection;(5)be
not be representative of chemicals associated with sediment in
easily maintained in the laboratory; (6) be easily identified; (7)
the field. Mixing time, aging and the chemical form of the
be ecologically or economically important; (8) have a broad
material can affect responses of test organisms in spiked
geographical distribution, be indigenous (either present or
sediment tests (10.6).
historical)tothesitebeingevaluated,orhaveanichesimilarto
organisms of concern (for example, similar feeding guild or
5.4 Evaluating effect concentrations for chemicals in sedi-
behavior to the indigenous organisms); (9) be tolerant of a ment requires knowledge of factors controlling their bioavail-
broad range of sediment physico-chemical characteristics (for
ability.Similarconcentrationsofachemicalinunitsofmassof
example, grain size); and (10) be compatible with selected chemicalpermassofsedimentdryweightoftenexhibitarange
exposure methods and endpoints (Table 1.3 in USEPA 2000)
in toxicity in different sediments (DiToro et al. 1990 (4), 1991
(8). The method should also be (11) peer reviewed (for (2)). Effect concentrations of chemicals in sediment have been
example, journal articles, USEPAorASTM methods) and (12)
correlated to interstitial water concentrations, and effect con-
confirmed with responses with natural populations of benthic centrations in interstitial water are often similar to effect
organisms.
concentrations in water-only exposures. The bioavailability of
4.10.2 Of these criteria, a database demonstrating relative nonionic organic compounds and metals in sediment is often
sensitivity to chemicals, contact with sediment, ease of culture inversely correlated with the organic carbon concentration;
in the laboratory, inter-laboratory comparisons, tolerance to moreover, the bioavailability of metals in sediment are often
varying sediment physico-chemical characteristics, and confir- inversely correlated with acid volatile sulfide. Whatever the
mation with responses of natural benthic populations were the routeofexposure,thesecorrelationsofeffectconcentrationsto
E1706 − 20
interstitial water concentrations indicate that predicted or sediment toxicity with field-collected sediment tests and with
measured concentrations in interstitial water can be used to sediment-spiking tests, (6) benthic community structure, and
quantifytheexposureconcentrationtoanorganism.Therefore,
(7) sediment quality triad integrating data from sediment
information on partitioning of chemicals between solid and
chemistry, sediment toxicity and benthic community structure
liquid phases of sediment is useful for establishing effect
(Burton1991 (28),Chapmanetal.1997 (29),USEPA2002a,b,
concentrations(DiToroetal.1990 (4),1991 (2);Wenningetal.
and c (20-22)). The sediment assessment approaches listed in
2005 (19)).
Table 1 can be classified as numeric (for example, ESGs),
descriptive (for example, whole-sediment toxicity tests), or a
5.5 Field surveys can be designed to provide either a
qualitative reconnaissance of the distribution of sediment combination of numeric and descriptive approaches (for
contamination or a quantitative statistical comparison of con- example, PECs). Numeric methods can be used to derive
tamination among sites. Surveys of sediment toxicity are
chemical-specific effects-based sediment quality guidelines
usually part of more comprehensive analyses of biological,
(SQGs). Although each approach can be used to make site-
chemical,geological,andhydrographicdata(USEPA2002a,b,
specific decisions, no one single approach can adequately
and c) (20-22). Statistical correlations may be improved and
address sediment quality. Overall, an integration of several
sampling costs may be reduced if subsamples are taken
methods using the weight of evidence is the most desirable
simultaneously for sediment tests, chemical analyses, and
approach for assessing the effects of contaminants associated
benthic community structure.
withsediment(USEPA2002a,b,andc (20-22),Wenningetal.
5.6 Table 1 lists several approaches used to assess of
2005 (19), Guide E1525, Guide E3163). Hazard evaluations
sediment quality. These approaches include: (1) equilibrium
integrating data from laboratory exposures, chemical analyses,
partitioning sediment guidelines (ESGs; USEPA 2003 (23),
and benthic community assessments (the sediment quality
2005 (24); Nowell et al. 2016 (25)), (2) empirical sediment
triad) provide strong complementary evidence of the degree of
qualityguidelines(forexample,probableeffectconcentrations,
pollution-induced degradation in aquatic communities (Burton
PECs; MacDonald et al. 2000 (26), Ingersoll et al. 2001 (27)),
1991 (28), Chapman et al. 1997 (29)). Importantly, the weight
(3) tissue residues, (4) interstitial water toxicity, (5) whole-
TABLE 1 Sediment Quality Assessment Procedures (Modified from USEPA 1992 (30))
Type
Method Approach
Numeric Descriptive Combination
Equilibrium Partitioning Sediment Guidelines * An ESG for a given contaminant is determined by calculating
(ESGs) the sediment concentration of the contaminant that
corresponds to an interstitial water concentration equivalent to
the USEPA water-quality criterion for the contaminant.
Emperical Sediment Quality Guidelines * * * The sediment concentration of contaminants associated with
toxic responses measured in laboratory exposures or field
assessments (that is, Apparent Effects Threshold (AET),
Effect Range Median (ERM), Probable Effect Level (PEL),
Probable Effect Concentration (PEC)).
Tissue Residues * Safe sediment concentrations of specific chemicals are
established by determining the sediment chemical
concentration that results in acceptable tissue residues.
Interstitial-water Toxicity * * * Toxicity of interstitial water isolated from sediment is
quantified and identification evaluation procedures are applied
to identify and quantify chemical components responsible for
sediment toxicity.
Whole-sediment Toxicity with Field-collected * * * Test organisms are exposed to whole sediments that may
Sediments and with Sediment Spiking contain known or unknown quantities of potentially toxic
chemicals. Dose-response relationships can be established
by exposing test organisms to whole sediments that have
been spiked with known amounts of chemicals or mixtures of
chemicals.
Benthic Community Structure * Environmental degradation is measured by evaluating
alterations in resident benthic community structure.
Sediment Quality Triad * * * Sediment chemical contamination, sediment toxicity, and
benthic community structure are measured on the same
sediment sample from the site of interest. Correspondence
between sediment chemistry, toxicity, and field effects is used
to determine sediment concentrations that discriminate
conditions of minimal, uncertain, and major biological effects.
E1706 − 20
oftheevidenceneededtomakeadecision(numberofmethods aquatic toxicity tests (for example, USEPA water quality
used) should be determined based on the weight (cost) of the criteria; Stephan et al. 1985 (31)).
decision.
6.1.3 Scope of Interferences Discussion—Because the defi-
nitionofaninterferenceinasedimenttoxicitytestissomewhat
6. Interferences
contextsensitive,theremainderofthissectiondoesnotattempt
to define issues specifically as to whether these factors should
6.1 General:
be considered interferences. Instead, several factors are dis-
6.1.1 Interferences in the Context of Sediment Toxicity
cussed that are known or suspected to be potential influences
Testing—In narrow terms, the purpose of a sediment toxicity
on the responses (including chemical accumulation) of organ-
test is to determine whether the constituents of a sediment
ismsexposedasdescribedinthisstandard.Theimportanceand
sample reduce performance of the test organism relative to a
implications of these factors for specific studies is left to the
control sediment, reference sediment, or some other sediment
investigator or the authority under which the study is con-
whose characteristics serve as a meaningful point of compari-
ducted.
son. Sediments that reduce relative organism performance are
generally considered to be “toxic”, or at least to have greater
6.2 Issues to Consider in Planning or Evaluating Sediment
toxicity that the sediment serving as a point of reference.
Tests:
Because the methods in this standard are intended to assess
6.2.1 Studies with Spiked Sediments versus Field-collected
sediment-associated contaminants, reduced organism perfor-
Sediments—Typically, spiked sediment tests are structured so
mance is generally attributed to the presence of those contami-
that the same sediment is tested with differing levels of
nants. So an interference in a sediment toxicity test can be
chemicaladded.Thisprovidesmuchgreaterconsistencyintest
thought of as a factor that causes a sediment to be judged
conditions across treatments than may exist in studies of field
non-toxic(forexample,notdifferentfromcontrol)wheninfact
samples collected at multiple sites, which may differ in many
the level of sediment contamination is sufficient that it should
different characteristics (for example, grain size, organic car-
decrease performance (a false negative) or a factor that causes
bon) beyond just contaminant concentration(s).As such, most
a sediment to indicate toxicity (for example, lower perfor-
oftheissuesdiscussedin6.2.2through6.2.6arelikelytobeof
mance relative to control) when in fact the reduced perfor-
greaterconcerninstudiesinvolvingmultiplesamplescollected
manceisnotcausedbysedimentcontaminants.Incaseswhere
from field sites.
a gradient in response is being assessed rather than simply
6.2.2 Sediment Collection and Handling Procedures—The
“toxic”or“nottoxic”,theseeffectscouldbeviewedascausing
processes involved in removing a bedded field sediment from
greater or lesser response than would be expected absent the
its field location site, and transporting, storing, and preparing
influence of the “interfering” factor.
the sediment sample for testing have the potential to alter the
6.1.2 Differences in Responses to Field-collected Sediments
characteristics of the sediment sample relative to conditions
when Tested in the Laboratory—Many applications of sedi-
occurring in the field. Section 10 describes a number of steps
menttoxicitytestsinvolvecollectionofbeddedsedimentsfrom
that can be taken to minimize undesirable changes associated
the field, that are subsequently tested in the laboratory. It is
with these processes. Assessment of sediment chemistry at
possible that differences between the physical or biological
appropriate points in time from collection to completion of
setting of the original field sediment and the conditions of a
testing can provide important information on the degree to
laboratorysedimenttoxicitytestcouldcreatedifferencesinthe
which handling, processing, and testing have affected test
apparentadverseeffectsthatmightresultfromexposure;thisis
sediments.
possible not only because of differences in the conditions
6.2.3 Grain Size—The organisms used in sediment tests
themselves, but also because of changes to the sediment that
describedinthisstandardwereselectedinparttobetolerantof
result from its removal from the field, storage, and manipula-
afairlywiderangeofgrainsize(seeSection1inUSEPA2000
tion as part of the preparation for and conducting laboratory of
(8)). Because the interactions of sediment contaminants with
sediment toxicity testing. Whether this potential is viewed as
sediment particles are generally surface-mediated processes,
an “interference” or simply a consequence of the measurement
largeparticles(forexample,<5mm)withsmallsurfaceareato
depends on the presumption of the investigator. Laboratory
volume ratios may have limited influence on the contaminant-
sediment toxicity tests are often used as tools to assess the
related response of organisms, and coarse sieving to remove
likely effects of sediment contaminants under field conditions,
theselargeparticlesisdiscussedinSection10andinAnnexA1
but this connection is not intrinsic to the test itself. The
to Annex A8. If there is a reason for concern that grain size
extrapolation of responses measured in the laboratory to those
may be an important influence on study results, testing of field
that might exist in the field is an important, but separate
reference samples, or control sediments amended to adjust
evaluation that is the responsibility of those designing and
particle size, may be a useful addition to a study.
implementing the overall sediment assessment program. It is
worth noting that the issue of laboratory to field extrapolation 6.2.4 Organic Carbon—Organic carbon content of sedi-
is by no means unique to contaminated sediment assessment, ments is known to affect the bioavailability of many sediment-
and while the issue is important to consider, the precedent of associated contaminants, both by the relative amount of or-
using laboratory tests to develop assessment guidance for ganic carbon present (DiToro et al 1991 (2), 2005 (32)), or by
pollution in natural systems is extensive, such as in the the nature and source of the particles comprising the organic
development of water quality guidelines from single species carbonfraction(Ghosh2007) (3).Whiletheamountandnature
E1706 − 20
of organic carbon can affect the relationship between contami- sediment-associated contaminants is not clear; while clean
nant concentration and effect, this would not generally be sediments that have high nutritional content could result in
considered an interference. Several studies have evaluated the growthabovethatfoundincontrolorreferencetreatments,itis
effect of different types, concentrations, or sources of organic not clear how much toxicant stress can be offset by the greater
carbon on the survival and growth of H. azteca and C. dilutus nutritional resources, thus potentially interfering with the
ability of the test to detect toxicant stress. In the reverse case,
(also C. riparius), and come to varying conclusions depending
in part on how the effect is assessed (for example, Lacey et al. wheretestsedimentsmighthavelowernutritionalcontentthan
the control or reference, a non-nutritive substrate, such as a
1999 (33), Ristola et al. 1999 (34), Suedel and Rogers 1994
sandcontrol,canbeusedasapointofcomparisonfororganism
(35), Ankley et al. 1994a (36)). Some of these studies did not
include supplemental feeding, and all were conducted before performance when organisms have only the nutrition provided
to all sediments. A sand control provides a reference for the
thedevelopmentofthefeedingregimesincludedinthecurrent
low end of performance that might be expected based on
sediment toxicity test methods described in this standard.This
limited nutritional content, but it is not necessary that a field
is important because in studies with no feeding, or insufficient
sediment perform more poorly than a sand control to be
feeding, responses to varying organic carbon can reflect the
considered potentially toxic.
potential for organic carbon to be a food source, in addition to
any other influence on organism performance. In an inter-
6.2.6 Density Dependent Growth—As discussed in 6.2.5,
laboratory study with H. azteca (Ivey et al. 2016) (37) which
the ration provided to C. dilutus does not support maximum
used the currently recommended feeding regimes described in growth rates. In cases where one or more midge larvae do not
Table A1.1 and Table A2.1, organisms provided with only
survive, there will be proportionately more food available to
silica sand as a substrate generally showed performance at or the survivors, raising the potential for higher growth. This
near that achieved using a field control sediment, demonstrat- potential was supported by a meta-analysis of growth and
ing that there is no minimum organic carbon content for the survival in control replicates from a large number of 10-d
substrate required for H. azteca to meet minimum control sediment tests with C. dilutus, which showed a general
performance requirements (Tables A1.1 and A1.2). Likewise, tendencytowardhigherthanaverageweightsinreplicateswith
C. dilutus fed as specified in AnnexA3 and AnnexA4 readily lower than average survival, and vice versa (Fig. A3.2;
meet the control performance criteria associated with those USEPA-Duluth unpublished data). The effect of density-
tests (USEPA-Duluth, USGS-Columbia, unpublished data). dependent growth can be compensated for, to some degree, by
Ankley et al. (1994a) (36) did not find a relationship between analyzing total biomass in addition
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