Standard Guide for Conducting In-situ Field Bioassays With Caged Bivalves

SIGNIFICANCE AND USE
5.1 The ecological importance of bivalves, their wide geographic distribution, ease of handling in the laboratory and the field, and their ability to filter and ingest large volumes of water and sediment particles make them appropriate species for conducting field bioassays to assess bioaccumulation potential and associated biological effects. The test procedures in this guide are intended to provide guidance for conducting controlled experiments with caged bivalves under “natural,” site-specific conditions. It is important to acknowledge that a number of “natural” factors can affect bivalve growth and the accumulation of chemicals in their tissues (Section 6, Interferences). This field bioassay can also be conducted in conjunction with laboratory bioassays to help answer questions raised in the field exposures. The field exposures can also be used to validate the results of laboratory bioassays.  
5.2 The ultimate resources of concern are communities. However, it is often difficult or impossible to adequately assess the ecological fitness or condition of the community or identify and test the most sensitive species. Bivalves are recommended as a surrogate test species for other species and communities for the following reasons: (1) They readily accumulate many chemicals and show sublethal effects associated with exposure to those chemicals (2); (2) they accumulate many chemicals through multiple pathways of exposure, including water, sediment, and food  (24, 25, 26, 27, 28, 29), and (3) caged bivalves have been shown to represent effects on the benthos more accurately than traditional laboratory tests (30, 31). Although bivalve species might be considered insensitive because of their wide use as indicators of chemical bioavailability, it has been suggested that sensitivity is related to the type of test, end points being measured, and duration of exposure  (2). In relatively short-term toxicity assessments in which survival is typically determined as the measureme...
SCOPE
1.1 This guide describes procedures for conducting controlled experiments with caged bivalves under field conditions. The purpose of this approach is to facilitate the simultaneous collection of field data to help characterize chemical exposure and associated biological effects in the same organism under environmentally realistic conditions. This approach of characterizing exposure and effects is consistent with the US EPA ecological risk assessment paradigm. Bivalves are useful test organisms for in-situ field bioassays because they (1) concentrate and integrate chemicals in their tissues and have a more limited ability to metabolize most chemicals than other species, (2) exhibit measurable sublethal effects associated with exposure to those chemicals, (3) provide paired tissue chemistry and response data which can be extrapolated to other species and trophic levels, (4) provide tissue chemistry data which can be used to estimate chemical exposure from water or sediment, and (5) facilitate controlled experimentation in the field with large sample sizes because they are easy to collect, cage, and measure (1, 2)2. The experimental control afforded by this approach can be used to place a large number of animals of a known size distribution in specific areas of concern to quantify exposure and effects over space and time within a clearly defined exposure period. Chemical exposure can be estimated by measuring the concentration of chemicals in water, sediment, or bivalve tissues, and effects can be estimated with survival, growth, and other sublethal end points (3). Although a number of assessments have been conducted using bivalves to characterize exposure by measuring tissue chemistry or associated biological effects, relatively few assessments have been conducted to characterize both exposure and biological effects simultaneously (2, 4, 5). This guide is specifically designed to help minimize the variability in tissue che...

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31-Mar-2022
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ASTM E2122-22 - Standard Guide for Conducting In-situ Field Bioassays With Caged Bivalves
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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: E2122 − 22
Standard Guide for
1
Conducting In-situ Field Bioassays With Caged Bivalves
This standard is issued under the fixed designation E2122; 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 rangeandcompartmentalizedcagesformultiplemeasurements
on the same individuals.
1.1 This guide describes procedures for conducting con-
1.2 The test is referred to as a field bioassay because it is
trolled experiments with caged bivalves under field conditions.
conducted in the field and because it includes an element of
The purpose of this approach is to facilitate the simultaneous
relative chemical potency to satisfy the bioassay definition.
collection of field data to help characterize chemical exposure
Relative potency is established by comparing tissue concen-
and associated biological effects in the same organism under
trations with effects levels for various chemicals with toxicity
environmentally realistic conditions. This approach of charac-
and bioaccumulation end points (6, 7, 8, 9, 10) even though
terizing exposure and effects is consistent with the US EPA
there may be more uncertainty associated with effects mea-
ecological risk assessment paradigm. Bivalves are useful test
surements in field studies. Various pathways of exposure can
organisms for in-situ field bioassays because they (1) concen-
be evaluated because filter-feeding and deposit-feeding are the
trate and integrate chemicals in their tissues and have a more
primary feeding strategies for bivalves. Filter-feeding bivalves
limitedabilitytometabolizemostchemicalsthanotherspecies,
may be best suited to evaluate the bioavailability and associ-
(2) exhibit measurable sublethal effects associated with expo-
atedeffectsofchemicalsinthewatercolumn(thatis,dissolved
suretothosechemicals,(3)providepairedtissuechemistryand
and suspended particulates); deposit-feeding bivalves may be
response data which can be extrapolated to other species and
best suited to evaluate chemicals associated with sediments
trophic levels, (4) provide tissue chemistry data which can be
(11, 12, 13, 14). It may be difficult to demonstrate pathways of
used to estimate chemical exposure from water or sediment,
exposure under field conditions, particularly since filter-
and (5) facilitate controlled experimentation in the field with
feedingbivalvescaningestsuspendedsedimentandfacultative
large sample sizes because they are easy to collect, cage, and
2
deposit-feeding bivalves can switch between filter- and deposit
measure (1, 2) . The experimental control afforded by this
feeding over relatively small temporal scales. Filter-feeding
approach can be used to place a large number of animals of a
bivalves caged within 1 m of bottom sediment have also been
known size distribution in specific areas of concern to quantify
used effectively in sediment assessments from depths of 10 to
exposure and effects over space and time within a clearly
650 m (5, 15, 16). Caged bivalve studies have also been
defined exposure period. Chemical exposure can be estimated
conducted in the intertidal zone (17). The field testing proce-
by measuring the concentration of chemicals in water,
dures described here are useful for testing most bivalves
sediment, or bivalve tissues, and effects can be estimated with
although modifications may be necessary for a particular
survival, growth, and other sublethal end points (3). Although
species.
a number of assessments have been conducted using bivalves
to characterize exposure by measuring tissue chemistry or
1.3 These field testing procedures with caged bivalves are
associated biological effects, relatively few assessments have
applicable to the environmental evaluation of water and
been conducted to characterize both exposure and biological
sediment in marine, estuarine, and freshwater environments
effects simultaneously (2, 4, 5). This guide is specifically
with almost any combination of chemicals, and methods are
designed to help minimize the variability in tissue chemistry
being developed to help interpret the environmental signifi-
and response measurements by using a practical uniform size
cance of accumulated chemicals (6, 7, 9, 18, 19). These
procedures could be regarded as a guide to an exposure system
to assess chemical bioavailability and toxicity under natural,
1 site- specific conditions, where any clinical measurements are
ThisguideisunderthejurisdictionofASTMCommitteeE50onEnvironmental
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