GUIDELINES FOR DERIVING AMBIENT AQUATIC LIFE
ADVISORY CONCENTRATIONS
Office of Water Regulations and Standards
Criteria and Standards Division
Washington, D.C.
Office of Research and Development
Environmental Research. Lab
Duluth, MN
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I. Introduction
A. Aquatic life advisories will be issued for selected
chemicals for which not enough toxicity, bioaccumulation
and/or field data are available to allow derivation of
ambient water quality criteria for aquatic life using
the procedures described in "Guidelines for Deriving
Numerical National Water Quality Criteria for the
Protection of Aquatic Organisms and Their Uses" (Stephen
et al. 1985), hereinafter referrred to as the "National
Guidelines". Aquatic life advisories will contain
compilations and interpretations of available data
chat ara directly pertinent to the derivation of
aquatic life advisory concentrations.
3. Aquatic life advisory concentrations are intended to
be used mostly for evaluating the aquatic toxicity of
concentrations of pollutants in effluents and ambient
waters, whereas water quality criteria for aquatic
lira provide a stronger basis for regulating concentra-
tions of pollutants in effluents and ambient waters.
Advisory concentrations have the following two intended
uses:
1. Advisory concentrations are intended to be used to
interpret data on concentrations of chemicals in
ambient water. If the concentration of a chemical
in ambient water is equal to or below the aquatic
life advisory concentration for.that chemical,
there is probably no cause for concern about
effects on aquatic organisms and their uses. If,
however, the ambient concentration is above the
advisory concentration, the discharger should
quickly evaluate the available exposure and effect
data to determine whether it is prudent to:
a. obtain additional data concerning the concen-
tration of the chemical in the effluent and/or
ambient water;
b. obtain additional laboratory and/or field data
on the effect of the chemical on aquatic
organisms and their uses so that a more accurate,
and usually higher, aquatic life advisory or a
water quality criterion can be derived;
c. conduct acute and/or chronic toxicity tests on
the effluent; and
d. reduce the ambient concentration of the chemical.
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After a reasonable period of time, the appropriate
regulatory agency should evaluate all available
pertinent data concerning the ambient concentration
and the effects of the pollutant on aquatic life
to determine whether it is appropriate to take any
action such as establishing a permit limit for the
pollutant or requiring toxicity tests on the
effluent. Such agency may choose to regulate
either before or after collecting additional data.
2. Advisory concentrations are intended to be used to
help the U.S. EPA select chemicals for which water
quality criteria for aquatic life should be derived.
Any chemical that is found to be present in a
considerable number of ambient waters at concentrations
similar to or exceeding the advisory concentration
may become a candidate for derivation of water
quality criteria for aquatic life. Thus advisories
-/ill provide dischargers with advance notice of
chemicals for which criteria might be derived so
that they can generate additional data that might
be useful for revising the advisory concentration
or for deriving water quality criteria for aquatic
life.
Additional guidance on appropriate regulatory uses
of advisory concentrations and criteria should be
obtained from the Criteria and Standards Division,
Office of Water Regulations and Standards, U.S. EPA.
C. The procedures described in the National Guidelines
will be used as much as possible in the derivation of
aquatic life advisory concentrations. Whenever a
procedure described in the National Guidelines cannot
be used (usually because some required data are not
available), a procedure that (a) follows as closely as
possible the procedures described in the National
Guidelines and (b) is compatible with the intended
uses of advisory concentrations will be developed for
use in deriving advisory concentrations. Aquatic life
advisory concentrations can be based on fewer data
than can water quality criteria for aquatic life
because advisory concentrations are not intended to
have as much regulatory impact as criteria. However,
to be compatible with the first intended use, advisory
concentrations must be derived so as to ensure that
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they are rarely, if ever, higher than what the Criterion
Continuous Concentration (CCC) would be if enough data
were available to allow derivation of a national aquatic
criterion Łor the chemical. The data requirements and
procedures used for deriving aquatic life advisory
concentration is rarely, if ever, above what the CCC
would be. Thus, whenever a national criterion is
derived for a pollutant for which an advisory
concentration is already available, the CCC will almost
always be higher than the advisory concentration. On
the other hand, an advisory concentration that is too
much lower than the CCC will cause unnecessary concern
about various chemicals, effluents and ambient waters.
To be most useful, the advisory concentration should
never be above what the CCC would be and should rarely
be more than a factor of 10 less than the CCC.
D. In order to obtain acceptable advisory concentrations
for the least cost, the da .a requirements and procedures
used for deriving aquatic life advisory concentrations
will be different for different classes of chemicals.
when possible, classes will be defined so that data
requirements and procedures can be appropriately based
on the biological, chemical, physical and toxicological
properties used to define the class.
II. Low Molecular Weight Non-ionizable Organic Chemicals
A. This class of chemicals is not very well defined yet.
It is expected, however, that all low molecular weight
non-ionizable organic chemicals will be in this class
after an upper limit on molecular weight has been
established. It might be possible to expand this
class to include a wider range of chemicals within
certain limits.
1. This class is intended to be limited to chemicals
for which there is no reason to suspect that the
range of acute or chronic sensitivities of saltwater
species will differ substantially from those of
freshwater species. Therefore, unless there is
substantial evidence to the contrary, the data
available for freshwater and saltwater species
should be considered together in order to derive
an advisory concentration that will apply to both
fresh and salt water. Because of the differing
ionic compositions of the waters, it seems reasonable
to assume that the toxicities and BCFs of organic
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chemicals that ionize and inorganic chemicals are
likely to differ in fresh and salt water.
2. This class is also intended to be limited to
chemicals whose range of toxicities to aquatic
animal species is relatively small, so that the
requirements for acute values do not have to
include very many species and do not have to be
very specific. Thus this class of chemicals should
not include any pesticides that are intended to be
effective against any aquatic or terrestrial
animals or any metals.
3. This class is also intended to be limited to
chemicals that are not especially toxic to plants,
so that tests with aquatic plants do not have to
be 'required. Thus this class of chemicals should
not include any herbicides.
3. An aquatic life advisory concentration should not be
calculated for a chemical unless data are available
from acceptable acute tests with at least three animal
species, such that:
1. at least one species is a fish in the class
Osteichthyes in the phylum Chordata.
2. at least two species are invertebrates such that:
a. at least one species is in the class Crustacea
in the phylum Arthropoda.
b. the other species is either in the phylum
Mollusca (test with embryos and larvae leading
to a 96 hour EC50 or LC50) or in a different
family of the phylum Arthropoda.
3. at least one is a freshwater species.
4. at least one is a saltwater species.
Available data from foreign species should be
included in the advisory, but not utilized to derive
an advisory recommendation unless other required
data is .not sufficient.
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Because =aany of the chemicals in this class are highly
volatile or degradable, acute tests with animals and
tests with plants that are otherwise acceptable (in
terras of acclimation, control mortality, etc. as
described in the National Guidelines) are acceptable
for this class of chemicals only if:
1. For flow-through tests, the concentrations were
measured. If concentrations fluctuated unreasonably,
the test should not be used.
2. For renewal tests, the organisms were exposed to
fresh test solution at least once every 24 hours
and either (a) the properties of the chemical
indicate that its concentration in water should
not decrease by more than 50% in 24 hours or (b)
measurements on tests solutions showed that the
concentration of test material did not decrease by
more than 50% in 24 hours.
3. For static tests, either (a) the properties of the
chemical indicate that its concentration in water
should not decrease by more than 50% in 96 hours:
(b) measurements on test solutions showed that the
concentration of test material did not decrease by
more than 50% from the beginning to the end of the
test or (c) results of a nominal or measured static
test should be multiplied by a factor obtained by
dividing a flow-through 96-hr LC50 by a comparable
static 96-hr LC50. The comparable flow-through
and static tests must be conducted on the chemical
in the same laboratory using the same water and
organisms from the same sources. The results of"
the flow-through tests must be based on the time-
weighted average measured concentrations of test
material and the results of the static test must
be based on the concentrations measured at the
beginning of the test.
D. Although data from tests with aquatic plants are
desirable they are not required because for many chemicals
it appears that aquatic plants are adequately protected
if aquatic animals are adequately protected.
E. For each species for which at least one acceptable
acute value is available, determine a Species Mean
Acute Value (SMAV) using the procedure described in
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the National Guidelines. (If data from tests in both
fresh and salt water are available for a species such
as striped bass, all the data should be used together
when determining the SMAV for that species.) Then
calculate a Genus Mean Acute Value (GMAV) for each
genus for which at least one SMAV is available.
An FAV should be calculated using the procedure
described in the National Guidelines if GMAVs are
available for at: least one animal species in at least
eignt different families, such that either:
1. the acute data requirements specified in the
National Guidelines for either fresh or salt water
are met, or
2. all the following are included:.
a. three families in the phylum Chordata such
that:
(1) at least one species is in the family
Salmonidae.
(2) at least one is a freshwater species.
(3) at least one is a saltwater species.
b. a saltwater penaeid shrimp or mysid.
c. a freshwater cladoceran.
d. a family in a phylum other than Chordata or
Arthropoda.
e. two other families not in the phylum Chordata.
As described in the National Guidelines, in some
situations a calculated FAV should be lowered to protect
an important animal species.
If the requirements for calculating an FAV are not met,
calculate an Advisory Acute Value (AAV) by dividing
the lowest available GMAV by the appropriate factor:
Number of GMAVs Factor
3 11.0
4 10.0
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Number of GMAVs
Factor
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20 or more
9.0
8.0
7.0
6.0
5.0
4.0
3.8
3.6
3.4
3.2
3.0
2.8
2.6
2.4
2.2
2.0
The AAV is intended to be equal to or slightly below
what the FAV would be if one could be calculated.
Since the factors for 8 GMAVs and above are only to be
used when those GMAVs are not acceptable under the
National Guidelines, the lowest factor has been set at
2, to provide a conservative estimate for the advisory
concentration. If there are 8 acceptable GMAVs, then
an FAV can be calculated directly.
H. If three or more experimentally-determined acute-
chronic ratios (ACR) which are acceptable based on the
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National Guidelines are available for the chemical,
determine the Final Acute-Chronic Ratio (FACR) using
the procedure described in the National Guidelines.
If fewer than three acceptable experimentally-determined
ACRs are available, use enough assumed ACRs of 25 so
that the total number of experimentally-determined and
assumed ACRs equals three (over 90% of the ACR reported
by both Kenaga (1982) and Call et al. (1985) were less
than 25 and nearly all the FACRs used to derive water
quality criteria for aquatic life have been less than
25). Calculate the Advisory Acute-Chronic Ratio (AACR)
as the geometric mean of the three ACRs. Thus is no v
experimentally-determined acute-chronic ratios are /'*
available, the AACR is 25.
I. Calculate the advisory concentration by
FAV (or the AAV i f an FAV cannot be determined^by the
FACR (or^the AACR if an FACR cannot be determined).
\*>
J. If necessary, the advisory concentration should be
lowered to one-half of the lowest EC50 for an important
aquatic plant species for which the EC50 is available
from an acceptable test, based on the National
Guidelines, in which the concentrations of test
material were measured and the effect was biologically
important.
K. If a Maximum Permissible Tissue Concentration (either
an FDA or other regulatory action level for seafoods
or from wildlife feeding studies, as described in the
National Guidelines) is available, back-calculate to a
concentration in water using a measured BCF (or a
predicted BCF if a measured BCF is not available). If
necessary, the advisory concentration should be lowered
to be equal to the calculated concentration.
L. The advisory should be stated as:
If the measured or estimated ambient concentration
of (a) exceeds (b) in fresh or salt water, one or
more of the following options must be completed
as quickly as possible:
1. obtain additional data concerning the concen-
tration of (a) in the effluent and/or ambient
water ;
2. obtain additional laboratory and/or field data
on the effect of (a) on aquatic organisms and
their uses so that a new aquatic life advisory
or a water quality criterion can be derived;
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3. conduct acute and/or chronic toxicity tests f
on the effluent;
4. reduce the concentration.
After a reasonable period of time, unless a considera-
tion of all available data concerning the ambient concen-
tration and the.effects of (a) on aquatic life demonstrate
that the ambient concentration is low enough, it must be
reduced.
i
where (a) = insert name of chemical and
(b) = insert advisory concentration
M. Caveats should be added to the advisory statement in some
situations:
1. If data for a commercially or recreationally
important species indicate that the species might
not be adequately protected by the advisory
concentration, but the data do not justify lowering
the advisory concentration (for example, because
the concentration of test material were not
measured), caveat should be added stating that the
species might not be adequately protected.
2. If ECSOs for a variety of species of algae (or
aquatic plants in general) are below the advisory
concentration, a caveat should be added stating
that algae (or aquatic plants) might not be
adequately protected.
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References
Call, D.J., L.T. Brooke, M.L. Knuth, S.H. Poirier and M.D..
Hoglund. 1985. Fish subchronic toxicity prediction
model for industrial organic, chepicals that produce
narcosis. Environ. Toxicol. Chem. 4:335-341.
Kenaga, E.E. 1982. Predicatability of chronic toxicity from
acute toxicity of chemicals in fish and invertebrates.
Environ. Toxicol. Chem. 1:347-358.
Stephan, C.E., D.I. Mount, D.J. Hansen, J.H. Gentile, G.A.
Chapman and W.A. Brungs. 1985. Guidelines for deriving
numerical national water quality criteria for the protection
of aquatic organisms and their uses. PB85-227049. National
Technical Information Service, Soringfield, Va.
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