600R08045
f/EPA
   United States
   Environmental Protection
   Agency
    Toxicology

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                                                           EPA/600/R-08/045
                                                             September 2008
          ENDANGERED AQUATIC VERTEBRATES: COMPARATIVE
                AND PROBABILISTIC-BASED TOXICOLOGY
                                    by

Foster L. Mayer1'5, Denny R. Buckler2, F. James Dwyer3, Mark R. Ellersieck4, Linda C.
            Sappington2, John M. Besser2, and Christine M. Bridges2
                    1U.S. Environmental Protection Agency
                    Office of Research and Development
         National Health and Environmental Effects Research Laboratory
                           Gulf Ecology Division
                          Gulf Breeze, FL 32561

                          2U.S. Geological Survey
                  Columbia Environmental Research Center
                           Columbia, MO 65201

                       3U.S. Fish and Wildlife Service
                           Columbia, MO 65201

                       4University of Missouri-Columbia
              College of Agriculture, Food and Natural Resources
                   Agricultural Experiment Station-Statistics
                           Columbia, MO 65211

                             5Present address:
                           8069 Constitution Rd.
                          Las Cruces, NM 88007

                    U.S. Environmental Protection Agency
                    Office of Research and Development
                       1200  Pennsylvania Avenue, NW
                          Washington, DC 20460

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                           TABLE OF CONTENTS
Notice	 iv
Abstract	 v
Figures	.,	vi
Tables 	vii
Acknowledgements 	viii

1.      Introduction	1
2.     Methods	.-	2

       Toxicity Tests	2
       Statistical Analyses	2
       Acute Toxicity	2
       Chronic Toxicity	3
       Estimating Toxicity	3
       Species Sensitivity Distribution (SSD)	3

3.     Results	4

       Comparative Toxicity Summary	  4
         Acute Toxicity	4
         Chronic Toxicity	5
       Estimating Toxicity 	5
         Acute Toxicity	  5
         Acute Estimate Accuracy and Uncertainty Analyses	5
         Chronic Toxicity	5
       Species Sensitivity Distribution (SSD)	5
         Acute Toxicity SSD 	5
         Chronic Toxicity SSD	6

4.     Discussion  	7
                                       111

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                                            NOTICE
The U.S. Environmental Protection Agency through its Offices of Research and Development, Pesticide
Programs, Pollution Prevention and Toxics, and Water partially funded and cooperated in the research
described herein under EPA project Nos. DW14935155, DW14936559, and DW14939002  (U.S. Geological
Survey, Biological Resources Division, Columbia Environmental Research Center, Columbia, MO) and
No. CR82827901 (University of Missouri, College of Agriculture, Food and Natural Resources, Agricultural
Experiment Station-Statistics, Columbia, MO).  It has been subjected to the Agency's peer and administrative
reviews and has been approved for publication as an EPA document. Mention of trade names or commercial
products does not constitute endorsement or recommendation for use.
                                          IV

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                                           ABSTRACT
Many times, endangered, threatened, and candidate endangered species (collectively known as listed
species) have been thought to be uniquely sensitive to chemicals.  The purpose of this cooperative
research effort (U.S. Environmental Protection Agency, U.S. Geological Survey, U.S. Fish and Wildlife
Service, University of Missouri) was to determine: 1)  if listed aquatic vertebrate species are more sensitive
to chemicals than non-listed species; 2) if common surrogate test species represent listed species
toxicologically; and 3) if predictive acute and chronic  models can be applied to hazard assessments with
listed species where direct toxicity testing is not prudent or impractical. Toxicity tests were conducted with
29 species of fishes and amphibians  (endangered species and a set of surrogates) and five chemicals
(carbaryl, copper, 4-nonylphenol, pentachlorophenol, and permethrin) representing a broad range of toxic
modes of action.  For acute toxicity, rainbow trout (Oncorhynchus mykiss), the most sensitive surrogate
species, was equal to or more sensitive than listed and related aquatic vertebrate species 80% of the
time.  Only 3% of the species were significantly (P< 0.05) more sensitive than rainbow trout, and even
then, the differences were within or very close to a factor of two (normal intra- and interlaboratory variation
= 2-5x). Under similar environmental conditions, chronic toxicity tests with copper and pentachlorophenol
indicated no significant greater sensitivity between rainbow trout and the listed species, spotfin chub
(Cyprinella monacha) and fountain darter (Etheostoma fonticola).  Using Interspecies correlation
estimation (ICE) for estimating acute  toxicity, 100% of the values for listed or related species were within
or very close to a factor of two of the  observed values (n = 70, mean = 1.1, range = 0.49 - 2.2). Acute-to-
chronic (ACE) estimated chronic toxicity values were within a factor of two of observed values 80-90% of
the time and 100% within a factor of three. Species sensitivity distributions (SSD) were also developed to
determine the 5th percentile effect among observed data and different sets of estimated data. The most
accurate estimated acute toxicity SSDs were in using the surrogate species having the best correlation
model in ICE (SSD = 0.95x observed SSD; range = 0.88 - 0.98). SSDs for chronic toxicity were also quite
good with  ACE-estimated chronic data or ICE-estimated acute data/acute-chronic ratio. 5th percentile
estimates  averaged 0.95 times those for observed data (range = 0.46 -1.3).  The results suggest that
listed aquatic vertebrate species are not universally more sensitive to contaminant exposure than other
aquatic vertebrate species on a toxicological basis. Surrogate test species do appear to represent listed
species toxicologically, at least for aquatic vertebrates, and toxicities and hazard assessments (SSD) can
be estimated accurately and precisely, not only for listed species, but other species with little or no toxicity
data as well.

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                                   FIGURES

                                                                                         Page

Figure 1a  Species sensitivity (static acute toxicity) distribution for carbaryl 	9
Figure 1b  Species sensitivity (static acute toxicity) distribution for copper	10
Figure 1c  Species sensitivity (static acute toxicity) distribution for 4-nonyiphenol	10
Figure 1d  Species sensitivity (static acute toxicity) distribution for pentachlorophenol 	11
Figure 1e  Species sensitivity (static acute toxicity) distribution for permethrin	11

Figure 2.   Sensitivity of darters relative to other aquatic species	12

Figure 3a  Species sensitivity distributions for observed acute toxicity data and
           ICE-based estimated data using the surrogate species (fathead minnow
           rainbow trout, or sheepshead minnow)  having the best correlation with
           the respective endangered species	 13

Figure 3b  Species sensitivity distributions for observed acute toxicity data and
           ICE-based estimated data using fathead minnow as the only surrogate
           species	 14

Figure 3c  Species sensitivity distributions for observed acute toxicity data and
           ICE-based estimated data using ECOSAR fish values as the only
           surrogate species	 15

Figure 4   Test species required to include most sensitive species for acute toxicity
            tests	16

Figure 5    Range of effects and geometric mean  of variables on acute toxicity of
            chemicals to aquatic organisms 	16
                                         VI

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                                         TABLES


 Table 1.    Surrogate and endangered species tested with carbaryl, copper, 4-nonylphenol,
           pentachlorophenol, and permethrin	17

 Table 2.    Acute static toxicity of carbaryl to surrogate test species and endangered
            species	18

 Table 3.    Acute static toxicity of copper and 4-nonylphenol to surrogate test
            species and endangered species	19

Table 4.    Acute static toxicity of pentachlorophenol and permethrin to surrogate
            test species and endangered species	20

 Tables.    Acute toxicity sensitivity rankings by 96-h LC50	21

 Table 6.    Chronic toxicity (ug/L) of copper (50 mg/L hardness) and
           pentachlorophenol (6.5 pH) to fathead minnow, spotfin chub,  rainbow
           and fountain  darter.	22

 Table 7.    Interspecies correlations (X2 = a + bX,) for all species with fathead
            minnow as the surrogate species	 23

 Table 8.    Interspecies correlations (X2 = a + bX^ for all species with rainbow trout
           as the surrogate species	24

 Table 9.    Interspecies correlations (X2 = a + bX,) for all species with sheepshead
           minnow as the surrogate species	25

 Table 10.  Correlation coefficients (r) and number of paired tests for all species and
           chemicals analyzed for interspecies correlations	26

 Table 11.  Observed and estimated 96-h LC50s  (ug/L) for five chemicals and 15
            aquatic vertebrates using interspecies correlation analysis (ICE) and
            surrogate species (fathead minnow, rainbow trout, or sheepshead
            minnow) acute toxicity values	27

 Table 12.  Observed and estimated (ACE) chronic toxicities (ug/L) of copper (50
            mg/L hardness)and pentachlorophenol (6.5 pH) for fathead minnow,
            spotfin chub, rainbow trout, and fountain darter.	28

 Table 13.  Calculated 5th percentile values for observed and estimated acute
            toxicity data  (96-h LC50s in ug/L) using three methods	29

 Table 14.  Calculated 5th percentile values (ug/L) for observed and estimated
            chronic toxicity data using three methods	30
                                          vn

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                                   ACKNOWLEDGMENTS
This project was sponsored in part by the U.S. Environmental Protection Agencys Office of Research
and Development, Pesticide Programs, Pollution Prevention and Toxics, and Water under Cooperative
Agreements DW14935155, DW14936559, DW14937809, DW14939002, and CR82827901; New York
Department of Environmental Conservation; and the U.S. Fish and Wildlife Service. We thank the federal,
state,  and private hatcheries that provided the species used in testing, as well as E. Greer for culturing
test organisms. Technical assistance was provided by W. Brumbaugh, E. Brunson, K. Feltz, J. Folse, D.
Hardesty, C. Henke, S. Holbrook, C. Ivey, J. Kunz, T. May, C. Orazio, M. Tanner, N. Wang, D. Whites, and
R. Wiedmeyer; technical suggestions and support by T. Augspurger, K. Hattala, C. Ingersoll,  D.R. Mount,
and G. Neuderfer; data analysis by A. Asfaw, V. Engle, and S.  Raimondo; and graphics by V. Camargo and
S. Embry. We also thank Valerie Coseo for manuscript preparation.  Peer reviews were contributed by T.
Augspurger, T. Bailey, K. Dickson, C. Flaherty, H. Galavotti, T. Henry,  J. Hyland, T.  Linton, D. Randall, M.
Reiley, D. Rodier, T. Steeger, and T. Waller.
                                           Vlll

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                                       1. INTRODUCTION
The widespread use of pesticides and other
commercial chemicals potentially poses a risk to
threatened and endangered species.  Because
by definition, the distribution of each species is
limited, additional adverse stresses on these
populations could lead to extinction. In addressing
the risk of chemicals to endangered species, the
U.S. Environmental Protection Agency (EPA)
is the primary federal agency that regulates
chemical substances in the environment of
the United States. This authority is granted
primarily within three statutes: the Federal
Insecticide, Fungicide, and Rodenticide  Act
(FIFRA; FL80-140), the Toxic Substance Control
Act (TSCA; PL94-469), and the Clean Water Act
(CWA; Section 101 (a) (3)). The FIFRA is used
to regulate pesticides that are manufactured
specifically for their toxicity and are intended for
direct application to the environment.  The TSCA
regulates the production, use, transportation, and
disposal of chemicals of commerce, excluding
pesticides. The CWA prohibits the discharge
of pollutants in toxic amounts to water bodies
of the United States. The Endangered Species
Act of 1973, affords additional environmental
protection through Section 7 consultations,
requiring Federal agencies to ensure that any
action authorized, funded, or carried out by them
is not likely to jeopardize the continued existence
of endangered species or modify their critical
habitat. The chemical registration and regulation
responsibilities of EPA fall under the Endangered
Species Act.

Toxicity testing under FIFRA may require four
categories of data, including acute toxicity tests
with freshwater, estuarine, and marine fish
and invertebrates; embryo-larval and life-cycle
studies with fish and invertebrates; chemical
residue studies; and field testing. In the  absence
of valid test data, TSCA risk assessments are
generally based on quantitative structure activity
relationships (QSAR). An integrated community-
based statistical approach is used to derive
water quality criteria, recommended under the
CWA, with a minimum multispecies data base
(Stephan et al. 1985) to protect aquatic organisms
from unacceptable adverse effects. As part of the
National Pollutant Discharge Elimination System
permit process, protection of aquatic environ-
ments from toxic discharges commonly includes
whole effluent toxicity tests with Ceriodaphnia
dubia, fathead minnow, and the alga, Selenastrum
capricornutum (U.S. EPA 1991).

The selection of surrogate test species used in
aquatic toxicity testing is critical to regulatory
processes  because of the need to be predictive of
a large number of species and their sensitivities,
including endangered species.  The test species
used for toxicity assessments are representative
and generally protective of other species, including
those that are threatened or endangered.  Mayer
and Ellersieck (1986) compiled an acute toxicity
data base for 410 chemicals and 66 species of
freshwater animals and reached three conclusions:
1) for a given chemical, acute toxicity among species
ranged over five orders of magnitude; 2) for a given
species, acute toxicity among chemicals ranged over
nine orders of magnitude; and 3) no single species
was always the most sensitive to all chemicals, but
a group of surrogate species, as used in U.S. EPA
programs, did include the most sensitive species
toxicity value most of the time.

Since the advent of the Endangered Species
Act, endangered species have sometimes been
assumed to be more sensitive to chemicals and
other stressors than non-endangered species.  A
more frequent concern is that sensitivity is unknown,
thus sensitivity estimates should include margins of
safety to avoid consequences of incorrect decisions
for  rare taxa. Under FIFRA, a margin of safety
is added to risk assessment levels of concern
for  endangered species.  With acute toxicity for
example, it is presumed that minimal risk will occur
to endangered aquatic organisms from pesticides
(Urban and Cook 1986) if:

    •    EEC (Estimated environmental
        concentration)/LC10 < 0.1  (when  a
        slope is available).

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   •    EEC/LC50 < 0.05 (when no slope is
        available).
   •    EEC < lowest chronic no-effect
        concentration.

TSCA does not provide the legislative authority to
require extensive testing, a priori, as does FIFRA.
The risk assessment process, many times, depends
upon quantitative structure activity estimates for
toxicity.  With CWA, it is generally assumed that
derived water quality criteria are protective of all
aquatic species. A  reasonable level of protection
(95%) will be provided if a diverse number of genera
are used in development of the criteria. In addition,
a margin of safety is added  by limiting exceedances
of the Criteria Maximum Concentration (CMC, acute
toxicity) or the Criteria Continuous Concentration
(CCC, chronic toxicity) values for 1  hour or 4 days,
respectively, once every 3 years; ammonia criterion
includes a longer averaging period. However,
there is no limit on  the exceedance in terms of
concentration. In order to meet the concentration/
frequency criteria from an engineering perspective,
a treatment plant must be designed with a goal of
keeping concentrations below the criteria, but  actual
discharge monitoring is not set up to capture the
frequency exceedance criteria.

Under current regulations, unnecessary margins of
safety may be applied for endangered species, if
their sensitivity to toxic chemicals is not understood.
Thus, a major question remains as to whether
endangered species may be more sensitive to
chemical  stressors than other species. More
important, however, in the absence of toxicity  data
for endangered species, what is a reasonable
protective estimate of the toxicity? To address these
questions, at least  in part, the objectives of this
effort were to:

    •   Summarize the toxicity data,
    •   Assess whether surrogate aquatic test
        test species are toxicoiogically
        representative of endangered aquatic
        vertebrate  species,
     •   Evaluate the application of acute and
        chronic estimation models for endangered
        aquatic vertebrate species, and
     •   Establish species sensitivity distributions
        (SSDs) for surrogate and endangered
        aquatic vertebrate species, contrasting
        5th percentile values of actual and
        estimated  data.
               2.  METHODS

2,1 Toxicity Tests

Static acute toxicity tests were conducted on
several species (Table 1) in basic accordance with
procedures described in ASTM (2003a).  Methods
for comparative toxicity are provided only briefly
since specific methods have been published
elsewhere (Besser et al. 2001, 2005; Bridges
et al. 2002; Dwyer et al. 1995, 1999a,b, 2000,
2005a,b; and Sappington et al. 2001). Additional
data (unpublished, C.M. Bridges, personal
communication) for larval amphibians and carbaryl
are also presented. Acute exposures for most
species included five chemicals  representing a
broad range of modes of action:

    •  Carbaryl - cholinesterase inhibitor
     •  Copper - osmoregulation
       interference
     •  4-Nonylphenol - narcotic and
       oxidative stressor
    •  Pentachlorophenol - oxidative
       phosphorylation uncoupler
     •  Permethrin - sodium channel blocker

Early life-stage toxicity tests were conducted
in general accordance with ASTM (2003b).
Chronic exposures included only copper and
pentachiorophenol tested with fathead minnow,
spotfin chub, rainbow trout, and  fountain darter.
For both acute and chronic tests, the copper
toxicity values were adjusted to  represent toxicity
at 50 mg/L hardness (U.S. EPA  1985) and
pentachiorophenol values adjusted to pH 6.5
(U.S. EPA 1986) except for Cyprinodontidae. Both
surrogate and endangered fishes and amphibians
were tested (Table 1).

2.2 Statistical Analyses

For the comparative toxicity summary, the data
of Besser et al. 2001, 2005; Bridges et al. 2002;
Dwyer et al.  1995, 1999a,b, 2000, 2005a.,b; and
Sappington et al. 2001 were used, but were
statistically re-analyzed for consistency or further
analyzed.

2.3 Acute Toxicity

LC50 Estimation. All raw data from our previous
publications were re-analyzed; 96-h LCSOs and
95% confidence limits (CL) were derived by  probit

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analysis (Finney 1978; PROC PROBIT-SAS/
STAT, SAS Institute Inc. 2004). In a few tests, the
LC50 was determined by linear interpolation, and
in 14 tests, the 96-h LC50 was derived by probit
analysis, but the respective 95% CL had to be
estimated using Spearman-Karber techniques
(Hamilton et al. 1977a, b). For some tests, CL
could not be estimated.

Comparative Toxicity.  The 96-h LC50 data
were analyzed by one-way analysis of variance
(Snedecor and Cochran 1989) to compare
species sensitivity within a chemical. Log10
transformation of toxicity data was used and
met the assumptions for normally distributed
data in analysis of variance. The design was
not balanced because the numbers of tests per
species for each chemical were unequal (number
of tests per species/chemical combination =
1 -6; replicates per test = 2-3). To determine
mean differences among LCSO's, Fisher's least
significant difference (LSD) was used (PROC
GLM-SAS/STAT, SAS Institute Inc. 2004). In
addition, sum of ranks/n analyses, based on the
Iog10 of the values or means, were also conducted.
2.4  Chronic Toxicity

Log10 chronic values for survival (arcsine
transormed) and growth were determined by
analysis of variance. Log10 chronic values were
then analyzed by an unbalanced n one-way
analysis of variance (Snedecor and Cochran
1989), followed by Fisher's LSD, to compare
species within a chemical by effect (PROC GLM-
SAS/STAT Institute Inc. 2004).

2.5  Estimating Toxicity

Acute toxicity estimation. Interspecies correlation,
Model II least squares methodology, (both
variables are independent and subject to
measurement error (Snedecor and Cochran
1989), was used to develop correlation models
for the surrogate test species (fathead minnow,
rainbow trout, sheepshead minnow) with all
other species tested.  Slopes and intercepts
were derived from the equation Iog10 X2 = a +
b(log10X1), where X2= the estimated 96-h LC50
for the species in question and X1 = the known
96-h LC50 value for one of the three surrogate
test species. When more than one LC50 value
existed for a species/chemical combination, the
geometric mean was used. A data set of correlation
parameters was established for these acute toxicity
data and estimates made with the ICE (Interspecies
Correlation Estimation) software (Asfaw et al. 2003).
Accuracy of 96-h LC50 estimates for endangered
and related species was determined by deriving
a ratio (estimated value/actual value), followed by
univariate analysis of the ratios  (PROC Univariate-
SAS/STAT, SAS Institute Inc. 2004).

Chronic toxicity estimation. Chronic toxicity values
of copper and pentachlorophenol were estimated
for fathead minnow, spotfin chub, rainbow trout,
and fountain darter using raw acute toxicity data
(mortality observations within each exposure
concentration time and at each  observation time
of 24, 48, 72, and 96 h) for the respective species.
Fountain darter and spotfin chub were selected
because of availability and  known culture techniques.
The Accelerated  Life Testing or  Linear Regression
Analysis models, within the Acute-to-chronic
estimation (ACE) v2.0 software  (Ellersieck et al.
2003, Mayer et al. 1999, 2002),  were used for the
estimations. Estimation accuracy was determined
by comparing predicted chronic values to actual
chronic values (geometric mean of no-observed-
effect [NOEC] and lowest-observed-effect [LOEC]
concentrations -r by observed values).

2.6  Species Sensitivity Distribution (SSD)

The assessment of hazard  was accomplished by
comparing toxicity responses of endangered to
surrogate test species (fathead  minnow, rainbow
trout, sheepshead minnow) and by comparing the 5th
percentile of species sensitivity  distributions (SSD)
to listed species toxicity values.  For estimating the
5th percentile of species sensitivity distributions,
three methods were used and compared  (described
below).  In addition, the 5th percentile estimations
were conducted for actual acute and chronic values,
values estimated by ICE (Asfaw et al. 2003) and
QSAR (quantitative structure-activity relationships)
for acute toxicity,  and values estimated by ACE
(Ellersieck et al. 2003) and  acute-chronic ratios
(ACR) for chronic toxicity.

Graphic species sensitivity  distributions were
derived using the methods  of Dyer et al. (2006).
The hazardous concentration protective of 95% of
species (5th percentile value or HC5) for all SSDs
was determined by the methods of Solomon et al.
(1996, 2000), Aldenberg and Jaworska (2000), and
Stephan et al. (1985). The  acute toxicity data sets

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that were used included: 1) observed data, 2)
data derived by ICE (Asfaw et al. 2003) using
the surrogate species (fathead minnow, rainbow
trout, or sheepshead minnow) having the best
correlation statistics, 3) data derived by ICE using
only the surrogate fathead minnow value, 4) data
derived by ICE using the ECOSAR (Ecological
Structure Activity Relationships) fathead minnow
value (U.S. EPA 2001), or 5) data derived by
ICE using the ASTER (Assessment Tools for
the Evaluation of Risk) fathead minnow value
(Russom 1991, 1997). The chronic data sets
used included: 1) observed data from criteria
documents (U.S. EPA 1985, 1986), 2) observed
data from criteria documents plus observed
data for fountain darter and spotfin chub, 3)
observed data from criteria documents plus ACE
(Ellersieck et al. 2003) estimated chronic values
for fountain darter and spotfin chub,  4) observed
data from criteria documents plus ICE (Asfaw
et al., 2003)  estimated acute values  divided by
the final criterion ACR (USEPA 1985, 1986) for
estimated chronic values for fountain darter and
spotfin chub, or 5) observed data for Daphnia
tnagna and fathead minnow with estimated
values for all other species (acute ICE estimates
divided by the ACR).

                 3.  RESULTS

3.1  Comparative Toxicity Summary

3.1.1   Acute Toxicity

Control survival, with and without solvent, was
always greater than 90% for all species except for
Atlantic and shovelnose sturgeons (< 90%).  For
these two species, control survival appeared to
be affected by the acetone carrier and only acute
toxicity results for copper (no solvent) with Atlantic
and shovelnose sturgeon are presented. Control
survival for fountain darter was acceptable, but
mortality (5-15%) occurred consistently among
all chemicals tested.  Ten percent or less is
considered acceptable (ASTM 2003). These
observations indicate that, any conclusions
regarding the acute chemical sensitivity of
sturgeon and fountain darters should be regarded
with caution until testing methodology has been
refined.  See Dwyer et al. (1995; 1999a,b; 2000;
2005a).

Overall, species of the families Acipenseridae,
Salmonidae, and Percidae were more sensitive
to the five chemicals than species in Cyprinidae,
Catostomidae, Cyprinodontidae, Poecillidae,
Bufonidae, and Ranidae (Tables 2-4, Fig. 1a -1e).
Differences between listed species and the suite
of surrogates were generally less than two-fold.
Permethrin was the most toxic compound and
carbaryl was the least toxic. The LC50s for rainbow
trout (Salmonidae) were always lower than the
LC50s for fathead (Cyprinidae) and sheepshead
minnows (Cyprinodontidae).

For carbaryl, 96-h LC50s ranged from 1435
ug/L (Apache trout) to 12,303 ug/L (boreal toad).
Amphibians were the least sensitive to carbaryl
(4592-12,303 ug/L) with all values being in the upper
50th percentile. Copper LC50s ranged from 18 ug/L
(fountain darter) to 1306 ug/L (Leon Springs pupfish).
Toxicity results with 4-nonyphenol ranged from 81
(shortnose sturgeon) to 553 ug/L (Leon  Springs
pupfish). Pentachlorophenol LCSOs ranged from
11 (shortnose sturgeon) to 191 ug/L (sheepshead
minnow).  Permethrin toxicity ranged from 1.7 (spotfin
chub and Lahontan cutthroat trout)  to 39 ug/L
(bonytail chub).

Based on 96-h LC50s, rainbow trout had a summary
sensitivity ranking across the five chemicals of 5.2
(Table 5). Only 5 of 23 species fell below that value,
and of those species lower LCSOs, the average
factor was 0.7 (± 0.2 SD) that for rainbow trout. The
summary ranking for fathead minnow across the
five chemicals was  13.2 (range of species rankings
- 2.0 to >18) and was one of the more tolerant
species tested overall.  The results  indicate that the
acute sensitivities of rainbow trout were equal to or
more sensitive than that for listed and other species
80% of the time. However, rainbow trout acute
toxicity values were equal to or within a factor of 2
of the most sensitive species 97% of the time; the 3
values exceeding a factor of 2 were: 4-nonylphenol
- shovelnose sturgeon  (0.42x) and fountain darter
(0.47x); pentachlorophenol - shortnose sturgeon
(0.44x) - - the only values that were significantly (P<
0.05) more sensitive than those for rainbow trout.
The ranking (Table 5) is in general agreement with
that previously derived by Dwyer et al. (2005).

As mentioned previously, the data for the fountain
darter, as well as sturgeons  should be used with
caution.  Further, the fountain darters in the present
study were very sensitive to copper. Five  other
darter species were 3.8 -7.9 times more tolerant (Fig.
2, U.S. EPA 1985).  Additional research  including
culture techniques used in acute toxicity testing is

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needed to determine if sturgeons and the fountain
darter are truly more sensitive to chemicals than
other species.

3.1.2 Chronic Toxicity

For copper, the fountain darter tended to be the
most sensitive species followed by rainbow trout,
fathead minnow, and spotfin chub. Although no
statistically significant differences (P < 0.05) were
found (Table 6), the sample size is small. Growth
was the slightly more sensitive endpoint overall
for both copper and pentachlorophenol.  Fathead
minnow was the most tolerant species tested with
pentachlorophenol. Fountain darter was the most
sensitive species, but the data for fountain  darter
were not significantly different from that for spotfin
chub and rainbow trout. See Besser et  al (2001,
2005).

3.2  Estimating Toxicity

3.2.1 Acute Toxicity

ICE (Asfaw et al. 2003) models were developed
for all species tested using the fathead minnow,
rainbow trout, or sheepshead minnow as the
surrogate species (Tables 7-9).  Correlations
were quite strong (r) and slopes (b) were close to
1.0 in most cases. Overall, the fathead  minnow
and rainbow trout were the  best surrogate
species representing other species.  Correlation
coefficients (r) were greater than 0.910  using
rainbow trout as the surrogate (Table 8), 0.882
for fathead minnow (Table 7), and  0.875 for
sheepshead minnow (Table 9).  No significant
slopes existed for boreal toad and the three
surrogate fishes.  However, the surrogate species
used should be as close as possible taxonomically
to the species being estimated (Asfaw et al. 2003).
The slope (1.090) is significant (p  =  0.04) when
using southern leopard frog as the surrogate for
boreal toad.  Correlations were also conducted
using each species tested as a  surrogate (Table
10). Most correlations were high (r > 0.90), with
lower r values  usually being associated with the
surrogate and other species not being from the
same taxonomic family.

3.2.2  Acute Estimate Accuracy and
Uncertainty Analyses

Of the 70 estimated acute toxicity  values, 96%
were within a factor of 2.0 (> 0.5 < 2.0) of the
observed values (Table 11). Three ratios, or 4%,
were only marginally greater than a factor of 2.0
(0.49, 2.1, 2.2). Univariate statistics of the ratios
of the estimated acute toxicity value divided by the
observed acute value (> 1.0, estimate higher than
observed; < 1.0, estimate lower than observed)
were:
Parameter
Value
Number of observations
Mean
95% confidence limits
Standard deviation
Standard error
Median
1 st - 99st percentile
5th - 95th percentile
10th-90th percentile
25th - 75th percentile
Range
70
1.06
0.98- 1.14
0.35
0.041
1.00
0.49 - 2.24
0.60-1.61
0.72-1.54
0.79-1.30
0.49 - 2.24
Previous interlaboratory and intralaboratory acute
toxicity test comparisons (DeGraeve et al.1991,
Lemke 1981, Schimmel 1981) demonstrated
that a two-to five-fold difference (i.e., highest/
lowest acute toxicity values) in LC50s existed for
the same species/chemical combinations and
methodology.  Intralaboratory test comparisons
in the same sources, indicated that LCSOs
seldom varied by more than a factor of 2.0.
Thus, the differences between observed and
estimated acute toxicity values with the species
examined are within, or are very close to, normal
intralaboratory variation.

3.3  Chronic Toxicity

Use of ACE (Ellersieck et al. 2003) proved highly
accurate as an estimator of chronic toxicity (Table
12).  Significant differences among ACE-estimated
values were not determined since each estimate
is a single value. Dividing the ACE estimated
value by the lowest Chronic Value, provided an
overall ratio of 0.98 (median, 1.1) or approximately
the same as the actual value. Regardless of the
analyses, 80 percent of the estimates were within
a factor of two of the observed values and two
estimates (0.33, 0.37) were still within  normal
intra- and interlaboratory variation (2-5x).

3.4  Species Sensitivity Distributions (SSD)

3.4.1  Acute Toxicity SSD

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Three frequently used SSD methods (Aldenberg
and Jaworska, 2000; Solomon et al. 1996, 2000;
Stephan et al. 1985) were applied to calculate 5th
percentile values for acute toxicity of the chemicals
to endangered vertebrates. This, by no means,
indicates a rigorous comparison of the methods
because the data sets are small (n = 15-18).
Wheeler et al. (2002) have previously assessed
different SSD statistical models for determining 5th
percentile values and found differences. Various
SSD models have been suggested (log-normal, log-
logistic, log-triangular and bootstrap techniques) as
well as using censored data sets for estimating the
5th percentile, but a consensus does not seem to
exist (Posthuma et al. 2002).  However, we conducted
these analyses to determine potential differences
between observed and estimated values among SSD
methodologies for endangered species. Examples
of SSDs for permethrin, comparing observed data
and three estimated data methods, and the model of
Aldenberg and Jaworska (2000) indicate that use of
estimated data leads to a more
conservative lower portion of  the curve and a less
conservative upper portion (Fig. 3a-c).

For acute data (Table 13), SSDs  were conducted with
three models (Solomon et al.  1996, 2000; Aldenberg
and Jaworska 2000, and Stephan et al. 1985) using
five data sets; 1) observed data,  2) ICE estimated
data for several tested species with observed values
using the  best correlation among three surrogate
species (fathead minnow, rainbow trout, sheepshead
minnow),  3) ICE estimated data using fathead
minnow only as the surrogate, 4) ECOSAR estimated
fathead minnow data, and 5)  ASTER estimated
fathead minnow data. The best estimated data, as
compared to observed data, to determine the 5th
percentile was obtained using the surrogate species
having the best correlation model in ICE.  The 5th
percentile estimates were slightly conservative and
averaged 0.94x (median = 0.92; SD =  0.08; range
= 0.81 - 1.1 x) that of observed data. Using fathead
minnow data only resulted in  a less conservative
mean factor of 1.2x (median = 0.99; SD = 0.54; range
= 0.64 - 2.7x).  Fathead minnow values determined
with QSAR (ECOSAR, ASTER) resulted in even less
conservative 5th percentile estimates, but were all
close to or within an order of  magnitude of observed
values (ECOSAR and ASTER - mean factor of 3.6x
[range = 0.27 - 12x],  ECOSAR -  mean factor of
4.4x [range = 0.43 - 12x], ASTER - mean factor of
2.2x [range = 0.27- 4.1x]). ASTER values resulted
in more accurate and less variable 5th percentile
estimates than ECOSAR; however, the data sets
were too small to make a good comparison
between the two QSAR estimate techniques.

The 96-h LC50 of the most sensitive species
tested (Tables 2-  4) was always greater than or
very close to the 5th percentile values generated
by the methods of Solomon et al. (1996, 2000)
and Stephan et al. (1985) (5th percentile mean
= 0.72x, range = 0.65 - 1.1 the most sensitive
species LC50 tested). The 5th percentile values
generated by the Aldenberg and Jaworska (2000)
method, regardless of observed or estimated data,
were always greater than the 96-h LC50 for the
most sensitive species tested (mean = 2.6x, range
3.4.2  Chronic Toxicity SSD

For chronic data (Table 14), SSDs were conducted
with the same three models as for acute data
and four data sets; 1 ) observed data from the
respective criteria document plus data for spotfin
chub and fountain darter, 2) observed data from
criteria document plus chronic data estimated
by ACE for spotfin chub and fountain darter, 3)
observed data from criteria document plus spotfin
chub and fountain darter data derived by ICE
estimated acute values divided by the ACR, and
4) observed data for Daphnia magna and fathead
minnow from criteria document plus all other
species estimated by ICE divided by the ACR.  All
three data sets containing data estimated by ICE
or ACE were highly accurate when compared
to the 5th percentile of the observed data set,
except for the SSD method of Stephan et al.
(1985).  Using Solomon et al. (1996, 2000) and
Aldenberg and Jaworska (2000), the first two data
sets containing estimated data (ACE and ICE for
the two endangered species) averaged the same
as the 5th percentile for observed  data (ACE -
factor of 1 .Ox, range = 0.83 - 1 . 1 x, ICE - factor of
1.0x, range = 0.94 - 1.1x). The data set having
observed data for Daphnia magna and fathead
minnow with ICE-estimated data for all other
species produced a 5th percentile value that was
also very close to observed data, but was more
conservative (average factor of 0.87x, range = 0.52
- 1 .3x) and more variable.

For observed copper data, the most sensitive
species chronic value (fountain darter, 2.7 ug/L)
was slightly greater than the 5th percentile value
(2.3 (jg/L) using Solomon et al. (1996, 2000) and
Stephan et al. (1985), but was less than half (0.4x)

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the SSD generated by Aldenberg and Jaworska
(2000). The 5th percentile values for data sets
containing estimated data were also less than the
chronic value for fountain darter, ranging from 0.45
to 2.4 ug/L, with the exception of Aldenberg and
Jaworska (2000), which ranged from 3.2 to 6.8
ug/L.  With pentachlorophenol,  all 5th  percentile
values derived with Aldenberg and Jaworska
(2000) were about two times greater than the
chronic value for fountain darter (3.9 ug/L), the
most sensitive species. The Solomon et al. (1996,
2000) technique resulted in somewhat consistent
5th percentile values that were slightly less than
the fountain darter chronic value.  The method of
Stephan et al. (1985) resulted in highly variable
5th percentile values (0.16-1.2  ug/L) well below
the fountain darter chronic value.

Various approaches in estimating chronic toxicity
data were also conducive to estimating 5th
percentile SSDs that corresponded well to SSDs
for observed data. Although small acute and
chronic data sets were  used, the SSD method of
Solomon et al. (1996, 2000) was conservative and
produced the most consistent SSDs for including
the most sensitive species. It may be that the
Solomon methodology  is best when using small
data sets.

               4. DISCUSSION

Overall, endangered fishes and amphibians do
not appear to be significantly more sensitive to
chemicals than non-endangered species, based
on the tests performed  here. This conclusion is
consistent to that reached by Hansen et al. (2002)
and Fairchild et al. (2005) who also indicated
that threatened and  endangered species are
not uniquely sensitive to toxicants. Also, the
surrogate test species evaluated were found to
be toxicologically representative of endangered
species.  Rainbow trout are especially useful when
estimating acute toxicity for sensitive organisms;
rainbow trout LCSOs were < those of sensitive
species 78% of the time but were within a factor
of two, 97% of the time. The three exceptions
had factors of 0.42 - 0.47x those of rainbow trout
and thus were very close to a factor of 2 (or
0.5). Dwyer et al. (2005a) found that a factor of
0.63 could be applied to a rainbow trout LC50
to estimate an endangered or other fish species
LC50. He further derived a conservative factor of
0.46 (0.63-1 SD) and a highly conservative factor
of 0.33 (0.63-2 SD).  It must also be kept in mind that
previous inter- and intralaboratory acute toxicity test
comparisons (DeGraeve et al. 1991, Lemke 1981,
Schirrtmel 1981) demonstrated that a two-to five-fold
difference (i.e., highest/lowest acute toxicity values)
in LC50s existed for the same species/chemical
combinations and methodology.  Intralaboratory test
comparisons indicated that LCSOs seldom vary by
more than a factor of 2.

Muffimert et al. (2003) reported ammonia LC50s
for mussels were 0.6 to 0.9 times LCSOs of rainbow
trout. In another study on effluent toxicity, Dwyer
et al. (2005b) indicated that endangered fishes
were more sensitive than fathead minnows 19%
of the time (0.2 - 0.9x) and more sensitive than
Ceriodaphnia dubia only 4% of the time (0.6 - 0.7x).
Besser et al. (2005) also found that chronic values for
two endangered fishes (fountain darter and spotfin
chub) were  approximately O.Sx that of rainbow trout
or greater. The significance of this is that a factor of
0.5 times the more sensitive surrogate test species
(i.e., rainbow trout or Ceriodaphnia dubia) appears to
encompass LCSOs, chronic values, or effluent IC25s
of the more sensitive endangered species.

The EPA guidance (U.S. EPA 1978, Stephan et
al. 1985) for determining a no- or low-acute-effect
concentration (Continuous Maximum Concentration,
CMC) requires multiplying the Final Acute Value
by 0.5. Dwyer et al. (2005a) determined that
the factor was 0.56 for the endangered fishes
studied. However, in other studies with ammonia
and freshwater mussels, toxicity to mussels was
approximately 0.1-0.6x (Augspurger et al. 2003) and
0.2-1.2x (Wang et al. 2007) that for the common
surrogate fish species tested, rainbow trout and
fathead minnow, respectively. Therefore, derived
safety factors (e.g., 0.5x) within  a taxa (e.g., fishes)
may not be  applicable to other taxa and specific
chemicals (i.e., mussels and ammonia), and thus
may not be  protective.

Surrogate test fishes do appear to represent
endangered fishes, in both toxicity and sensitivity.
Although Mayer and Ellersieck (1986) stated that
"no single species was always the most sensitive
to all chemicals," they further reported that, in a
comparison of 40 chemicals, the most sensitive
species could be identified using a combination
of surrogate test species (i.e., either Daphnia or
rainbow trout were the most sensitive 93% of the
time; in the other 7%,  fathead minnow or bluegill

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were the most sensitive - - all surrogate test
species). A further analysis of random surrogate
species toxicological representation of other
species among all chemicals (data from Mayer
and Ellersieck, 1986) indicated that a suite of
three test surrogates (daphnids,  rainbow trout, and
gammarids) could account for the most sensitive
species 87.5% of the time (Fig. 4); additional test
species contributed only 2.5% each to identifying
the most sensitive species.

The major acute and chronic toxicity testing
programs for aquatic species that existed in
government and industry basically ended in
the mid 1980s, and no major toxicity testing
programs are anticipated in  the near future. Thus,
methods for probability-based toxicology and risk
assessment are a priority, including predictive
toxicology and probability-based risk assessment
for endangered species -- all species cannot
practically be tested with all chemicals. The
greatest range of uncertainty in acute toxicity
tests is due to species within a chemical and
chemicals within a species (Fig.  5). With the data
of Mayer and Ellersieck (1986), it was found that
acute toxicity data for species within a chemical
ranged as high as 5 orders of magnitude and
chemicals within a species,  ranged up to 9 orders
of magnitude. The uncertainty of acute toxicity
estimates for chemicals within a species should
be addressed with quantitative structure activity
relationships (QSAR), although QSAR is generally
limited to three organisms (fathead minnow,
daphnid, and an alga). ICE and ACE were
developed to address the uncertainty of species
within a chemical.

Acute and  chronic estimation models (ICE,
A-sfaw et al. 2003; ACE, Ellersieck et al. 2003)
were shown to be both highly accurate and
precise in estimating acute and chronic toxicity to
endangered species.  Of 70 ICE-estimated acute
toxicity values, 96% were within  a factor of 2.0
(range = 0.49-2.2) of the observed values. The
mean factor was 1.1 (SD - 0.35) with a median
of 1.0 (>1.0, estimate higher than observed; <1.0,
estimate lower than observed).  ACE-estimated
chronic values were also very close to observed
values. The mean factor was 0.9 (range = 0.33 -
1.6), with two of ten factors  being slightly greater
than a factor of 2.0 (0.33 and 0.37). Mayer et al.
(2002) also found a very high degree of accuracy
in predicting  chronic toxicity from acute toxicity
data using time-concentration-effect models
(ACE v1.0, Mayer et al. 1999) with 7 fish species
and 18 chemicals. The significance of the ICE and
ACE estimations is that they are all within normal
intra- and  interlaboratory variation (2-5x), and thus
acute and chronic values for endangered fish and
other aquatic vertebrate species can be accurately
estimated when toxicity values do not exist.  If a
correlation for a specific endangered species does
not exist in ICE, the genus or family value of the
endangered species can be estimated, although
the estimated genus or family values may have
more uncertainty than an estimated species value.
Also, the method of Dwyer et al. (2005a) could be
used; i.e., 0.5x the rainbow trout acute and chronic
values  or Ceriodaphnia dubia effluent values. If an
acute toxicity value does not exist for rainbow trout,
it can be estimated with ICE. Raw acute data are
required to use ACE for chronic value estimations.
If these data are not available for the species in
question, raw data from an acute rainbow trout test
could be used in ACE, applying a factor of 0.5x to
the estimated chronic value to calculate chronic
toxicity to the endangered aquatic vertebrate.

Species sensitivity distributions (SSDs) conducted
on observed and estimated acute toxicity data
indicated that estimated data can be used to
accurately and precisely determine 5th percentile
values that include the most sensitive species
tested, particularly ICE-estimated data using the
best interspecies correlation with appropriate
surrogate species (i.e., in this case, fathead
minnow, rainbow trout, or sheepshead minnow).
Using fathead minnow as the only surrogate for
ICE  estimates or QSAR estimated data, tended
to become less conservative and more variable
in determining 5th percentile values, and thus,
less  likely to include the 96-h LC50 for the most
sensitive species tested.  Dyer et al. (2006) also
found SSDs for ICE-estimated data corresponded
well  to SSDs for observed data, but the results
were more variable as they used only one
surrogate species per SSD determination. Various
approaches in estimating chronic toxicity data
were also conducive to estimating 5th percentile
SSDs that corresponded well to SSDs for
observed data. Although small acute and chronic
data sets were used, the SSD method of Solomon
et al. (1996, 2000) was conservative and produced
the most consistent SSDs for including the most
sensitive species.  It may be that the Solomon
methodology is best when using small  data sets.

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The results of these studies suggest that
threatened and endangered species do not
appear to be universally more sensitive to
contaminant exposure than other species frorri a
toxicological standpoint. However, it is important
to consider the consequences of additional
pressure on species populations that are already
stressed.  By definition, population numbers,
genetic variability, and habitat availability for
endangered species are low.  Toxicant stress
that might be assimilated by a healthy population
could have a much more severe effect on a
fragile and sensitive population. The removal
of a portion of  a robust population via fishing
pressure,  habitat alteration, or even toxicant
stress has been deemed to be legal under
current regulations. The 1985 guidelines
(Stephan et al. 1985) state that because aquatic
ecosystems can tolerate some stress and
           occasional adverse effects, protection of all
           species at all times and places is not deemed
           necessary.; If criteria are developed with that in
           mind, then loss of individuals within threatened
           and endangered species populations may
           become very real. Considering that threatened
           and endangered species, at least vertebrates,
           do not appear to be significantly more sensitive
           to chemicals than other species, the data and
           modelling methodology presented herein can be
           used to develop approaches for identifying critical
           chemical concentrations for those as well as
           other species having little or no data.
          1.0-
          0.8
      -Q
      JS   0.6
      o
      1   0.4
      E
      O
          0.2-
          0.0-
                  Carbaryl

                                       • G, pseudolimnaeu^,
                                     • D. magna   —
                                            Boreal toad
                                         Bullfrog
                                       Pickerel frog
                                     'Plains leopard frog
                                     Oregon spotted frog
                                 / W Green frog
                                   /Spotted salamander
                                   > Southern leopard frog
                                   ' Desert pupfish
                                  1 Bluegill
                                 ' Gray tree frog
                                 i Fathead minnow
                                ' Foothill yellow-legged frog
                                1 Leon Springs pupfish
                                1 Razorback sucker
                                »Cape Fear shiner
                               1 Spotfin chub
                               Bonytail chub
                              1 Colorado pikeminnow
                             'Sheepshead minnow
                             1 Lahontan cutthroat trout
                             1 Greenthroat darter
                            ' Shortnose sturgeon
                          f O Rainbow trout
                           1 Fountain darter
                          • Greenback cutthrout trout
                          * Apache trout
                          0.001
""I
 0.01
11 Mill
   0.1
10
'	I
   100
                                        48-h EC50 or 96-h LC50 (mg/L)
       Figure 1a. Species sensitivity (static acute toxicity) distribution for carbaryl  (o = designated
       surrogate test species for comparison). Dashed line = lower 95% confidence limit. D. magna
       and G. pseudolimnaeaus (Mayer and Ellersieck 1986) were added as reference points.

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o
<£
   1.0 -
   0.8 -
   0.6-
   0.4 -
   0.2 -
   0.0 -
           Copper
                                  •Bluegill
                    Fathead minnow
                 • Colorado pikeminnow
               > Greenthroat darter
        /   / • Razorback sucker
       /  /• Bonytail chub
      / */Gila topminnow
          Southern leopard frog
        Spotfin chub
      •/Cape Fear shiner
      'Apache trout
      Shortnose sturgeon
     Boreal toad
    G. pseudolimnaeus
   Lahontan cutthroat trout
   D. magna
O Rainbow trout
• Fountain darter
           \
          1.0
10                  100
        48-h EC50 or 96-h LC50 (ug/L)
                                 1,000
                                                        10,000
  Figure 1b. Species sensitivity (static acute toxicity) distribution for copper (o = designated
  surrogate test species for comparison).  Dashed line = lower 95% confidence limit. D, magna
  and G. pseudolimnaeus (USEPA 1985) were added as reference points.
    1.0 -
    0.8 -
 I  °-6
 o
    0.4-
    0.2 -
    0.0 -
           4-Nonylphenol
                           Southern leopard frog
                          ' Sheepshead minnow
                          Fathead minnow
                          Bonytail chub
                         Gila topminnow
                         Colorado pikeminnow
                        Cape Fear shiner
                        Bluegill
                       Rainbow trout
                       Razorback sucker
                      Greenthroat darter
                      Lahontan cuttroat trout
                      Apache trout
                     Greenback cutthroat trout
                    Boreal toad
                    Leon Springs pupfish
                   D. magna
                  Spotfin chub
                 Fountain darter
                Shortnose sturgeon
          1.0
10                 100
        48-h EC50 or 96-h LC50 (ug/L)
                                r-r-q	
                                 1,000
                                                                                        10,000
    Figure 1c. Species sensitivity (static acute toxicity) distribution for 4-nonylphenol (o = designated
    surrogate test species for comparison). Dashed line = lower 95% confidence limit. D. magna
   (U.S. EPA 2003) was added as a reference point.
                                              10

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S
CL
   1.0 -
   0.8
   0.6 H
   0.4 -
   0.2 -
   0.0
          Pentachlorophenol
                                                    O Sheepshead minnow
                                                   G. pseudolimnaeus
                                                  Leon Springs pupfish
                                               • Boreal toad
                                               . magna
                                            Bluegill
                                            Gila topminnow
                                           Southern leopard frog
                                          Razorback sucker
                                          Fathead minnow
                                         Spotfin chub
                                        Bonytail chub
                                        Cape Fear shiner
                                       Greenback cutthroat trout
                                      Lahontan cutthroat trout
                                     Greenthroat darter
                                     Rainbow trout
                                  ' Colorado pikeminnow
                                 f Apache trout
                                 Fountain darter
                             'Shortnose sturgeon
                                                                    T~
         1.0
                           10                 100

                                  48-h EC50 or 96-h LC50 (ug/L)
                                                                   1,000
                                                                                      10,000
Figure 1d.  Species sensitivity (static acute toxicity) distribution for pentachlorophenol (o - designated
surrogate test species for comparison).  Dashed line = lower 95% confidence limits.  D. magna and G.
pseudolimnaeus (USEPA 1986) were added as reference points.
     1.0 -
     0,8
I?
15
o

•I
JS
3
E
o
     0.4-
     0.2
     o.o-
            Permethrin
                                Bonytail chub
                            'Colorado pikeminnow
                            Sheepshead minnow
                          >  Leon Springs pupfish
                           Southern leopard frog
                     > Giia topminnow
                   fO Fathead minnow
                  ' Razorback sucker
                  Bluegill
            /• cApe Fear shiner
           I •/Fountain darter
              'Rainbow trout
             'Greenthrout darter
             Greenback cutthroat trout
           ' Apache trout
         [ Lahontan cutthroat trout
         ' Spotfin chub
  •prmagna
 Jolimnaeus
            I—
          0.01
                        0.1
    1.0              10

48-h EC50 or 96-h LC50 (ug/L)
                                                                       100
    Figure 1e. Species sensitivity (static acute toxicity) distribution for permethrin (o = designated
    surrogate test species for comparison). Dashed line = lower 95% confidence limit. D. magna
    and G. pseudolimnaeus (Mayer and Ellersieck 1986) were added as reference points.
                                        11

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   1-0 -j    Copper
   0.8-
I  0.6
o
oi
£
3
O
   0.4-
   0.2 -
    o.o-
                                                              .
                                                             '
                                                            /
                                                             •
                                         X
                                                      • White perch
                                          -_         •American eel
                                          • Bluegill
                                          Banded killfish
                                        • Mozambique tilapia
                                        • Pumpkinseed
                                   ,  Striped shiner
                                 = . Sockeye salmon
                               /(.yOrangetnroat darter
                                •/Atlantic salmon
                              /J^Mosquitofish
                                 Striped bass
                                Johnny darter
                            /  W Common carp
                            '  •Goldfish
                               Chiselmouth
                               Guppy
                              Fathead minnow
                            -. Fantail darter
                         /  9 Brook trout
                           OGreenthrout darter
                        / IrBlacknose dace
                        .  O Rainbow darter
                        /  W Creek chub
                       . f Central stoneroller
                       / g Bluntnose minnow
                           Brown bullhead
                           Coho salmon
                          Cutthroat trout
                        Rainbow trout
                        Chinook salmon
                      'Scud (G. Dulex)
                      Daphnid (D. pulex)
                    'Scud (G, pseudolimnaeus)
                    Daphnid/D. magna)
                   Daphnid (C. reticulate)
                  Fountain darter
                  Northern squawfish
              Daphnid (D. pulicaria)
            I

           0.1
1.0
     10               100


48-h EC50 or 96-h LC50 (ug/L)
1000
10,000
 Figure 2.   Sensitivity of darters (o) relative to other aquatic species (•  ) for copper (data from U.S. EPA
 1985). Dashed line = lower 95% confidence limit.
                                                 12

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o
QL

-------
   1.0 -
   0.8 -
£  0.6 -
o
£
I 0.4-
o
   0,2 -
    0.0 -
            Permethrin B
               Observed Data
                    Bonytail chub/^t0sheepshead minnow
          Colorado pikeminnow/  ^Leon Springs pupfish
        Sheepshead minnow//«OBonytail chub
                     Leon Springs pupfistr •   ©Colorado pikeminnow
                   Southern leopard frog^J     OSouthern leopard frog
                       Gila topminnowT»Gila topminnow
                    Fathead minnow/•Fathead minnow
                Razorback suckerQ/Razorback sucker
            Cape Fear shinerQ  •//Greenback cutthroat trout
             Fountain darterO  »/Greenthroat darter
              Rainbow troutO 9 /Cape Fear shiner
          Greethroat darterQ f /Rainbow trout
   Greenback cutthroat trout 9/ /Fountain darter
          Apache troutQ^ii/Apache trout
Lahontan cutthroat troutO" /•Spotfin chub
   Spotfin chub ,*• " j*3   • Lahontan cutthroat trout
                                              Estimated Data
                                              Surrogate
                                                 • Fathead minnow
           I
           0.1
1.0
                                   10
                            96-h LC50 (ug/L)
                                          100
1 ' i
1000
 Figure 3b.   Species sensitivity distributions for observed acute toxicity data and ICE-based
 estimated data using fathead minnow as the only surrogate species.  Species common names to
 left of curve are observed data (o—) and species names to right of curve are estimated data <• —);
 when only one value exists between two species ( •), the values are approximately the same.
                                                14

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   1.0-
   0.8-
   °-6
2
a.
3
o
   0.4
   0.2-
   0.0
           Permethrin C
               Observed Data
                                 Bonytail chub/'pOSheepshead minnow
                                          Xxf
                       Colorado pikeminnow/^OLeon Springs pupfish

                      Sheepshead minnow^ • QBonytail chub

                     Leon Springs pupfisbMl   OColorado pikeminnow

                  Southern leopard frog/fr   O Gila topminnow

                      Gila topminnowAO Southern leopard frog

                    Fathead minnow I'9Q Fathead minnow

                Razorback sucker 
-------
                    UJ

                    I
                    S
                    ^
                    o
 100

  90 -


  80


3 70

  60 -


  50-
                                                 i
                                                 A
                              i
                              B
                          40
                           Daphnids
                                 Rainbow
                                 Trout
                                     Gammarids
                                             SPECIES

Figure 4. Test species required to include most sensitive species for acute toxicity tests (A-E represents
randomly selected other species).  Cumulative % = species combinations including the most sensitive
species x% of the time,  beginning with daphnids only (e.g., testing only daphnids,rainbow trout and
gammarids can include the most sensitive species 87.5% of the time).
                                            Temperature
                                            pH
                                            Fish size-extreme
                                            Fish size - normal (ASTM)
                                            Life stage • invertebrates
                                            Life stage - fish
                                            Source-fish
                                            Diet-fish
                                            Pesticide formulation
                                            Static vs. flo-thru
                                                              Species within a chemical
                                                           Chemicals within a species
                •10123456          9
                                      Orders of Magnitude

Figure 5.  Range of effects and geometric mean of variables on acute toxicity of chemicals to aquatic
organisms. Range = highest EC/LC50 value + lowest value within a particular variable test and chemical;
geometric mean ( • ) of ranges among all tests for that variable (data from Mayer and Ellersieck 1986).
                                             16

-------
  Table 1. Surrogate, endangered, and related species tested with carbaryl, copper,
           4-nonylphenol, pentachlorophenol, and permethrin (Bridges et al. 2002, Dwyer et al.
           1999a,b, 2000a, Sappington et al. 2001).
   Family
     Species
   Family
      Species
Acipenseridae
  Shovelnose sturgeon**
    Scaphirhynchus platorynchus
  Shortnose sturgeon ***
    Acipenser brevirostrum
  Atlantic sturgeon ***
    Acipenser oxyrhynchus
Cyprinidae
  Fathead minnow*
    Pimephales promelas
  Bonytail chub ***
    Gila elegans
  Cape Fear shiner***
    Notropis mekistocholas
  Colorado pikeminnow ***
    Ptychocheilus lucius
  Spotfin chub ***
    Cyprinella monacha
Castostomidae
  Razorback sucker ***
    Xyrauchen texanus
Salmonidae
  Rainbow trout*
    Oncorhynchus mykiss
  Apache trout ***
    Oncorhynchus apache
  Lahontan cutthroat trout ***
    Oncorhynchus clarki henshawi
  Greenback cutthroat trout ***
    Oncorhynchus clarki stomias
Cyprinodontidae
  Sheepshead minnow*
    Cyprinodon variegatus
  Desert pupfish ***
    Cyprinodon macularius
  Leon Springs pupfish ***
    Cyprinodon bovinus
Poecilidae
  Gila topminnow ***
    Poeciliopsis occidentalis
Percidae
  Fountain darter ***
    Etheostoma fonticola
  Greenthroat darter***
    Etheostoma lepidum
Bufonidae
  Boreal toad ***
    Bufo boreas
Hylidae
  Gray tree frog*
    Hyla versicolor
Ranidae
  Plains leopard frog*
    Rana blairi
  Foothill yellow-legged frog*
    Rana boyli
  Bullfrog*
    Rana catesbeiana
  Green frog*
    Rana clamitans
  Pickerel frog*
    Rana palustris
  Oregon spotted frog,***
    Rana pretiosa
  Southern leopard frog**
    Rana sphenocephala
Ambystomatidae
  Spotted salamander
    Ambystoma maculatum
  * Surrogate test species for studies included.
 ** Species identified as surrogates in U.S. Fish and Wildlife Service Recovery Plans.
*** State and/or federally listed (threatened or endangered species).
   *Non-listed species.
                                            1-7

-------
Table 2.  Acute static toxicity of carbaryl to surrogate test species and endangered species.1 Number
        of tests = 1-6/species; replicates/test'= 2-3.
Family
  Species common name
96-h LC50 (ua/LV
 95% CU
Acipenseridae
   Shortnose sturgeon **
Cyprinidae
   Fathead minnow*
   Bonytail chub **
   Cape Fear shiner **
   Colorado pikeminnow **
   Spotfin chub **
Catostomidae
   Razorback sucker **
Salmonidae
   Rainbow trout*
   Apache trout **
   Greenback cutthroat trout **
   Lahontan cutthroat trout **
Cyprinodontidae4
   Sheepshead minnow*, 2ppt
   Sheepshead minnow*, 15ppt
   Desert pupfish**,15ppt
   Leon Springs pupfish **, 2ppt
   Leon Springs pupfish **, 15ppt
Poecillidae
   Gila topminnow **
Percidae
   Fountain darter **
   Greenthroat darter**
Bufonidae
   Boreal toad**
   Hylidae
   Gray tree frog
Ranidae
   Plains leopard frog
   Foothill yellow-legged frog
   Bullfrog
   Green frog
   Pickerel frog
   Oregon spotted frog **
   Southern leopard frog
Ambystomatidae
   Spotted salamander
 19491 .i.j .k

 5171bcds
 3044° de '9
 3038 e- ' 9 h '• '
 34-jgd.e.f.g.h
 1866hJ--;-k
 1435k
 1553''K
 2221 9 h ' ' K

 4362 cd el
 2511 fg.h.i.j.
 7714abc
 454Qc.de.!
 2017 hi'k

>3000

 1615'ik
12303a

 6214abcd

11477a
 4592 cde.<
11830a
 9523 "•"
11487a
 9632 ab
 7964abc

 8034 abc
1560-2354

4922 - 5437
2723-3413
3551 -5197
2803 - 3296
3123-37373

4087 - 4626

1766- 1972
1292- 1594
1368- 1760
2076 - 2380

3839-5120
2175-2905
6082-12332
4043-5179
1696-2390
1234-2362
1732-2872
5757-6710
10621
3956-
10709
8617-
10710
8794-
6916-
- 12469
5166
- 13110
10553
- 123163
10586
9232
7294 - 8879
  'Surrogate test species.
 "Listed species.
 1 Means with same letter are not significantly different (p > 0.05).
 2 Confidence limits.
 3 Confidence limits estimated by Spearman-Karber techniques (Hamilton et al. 1977 a,b).
 4 Cyprinodontids were tested under two salinity conditions, 2 or 15 parts per thousand salinity (ppt).
                                          18

-------
Table 3. Acute static toxicity of copper and 4-nonylphenol to surrogate test species and endangered species.1
        Number of tests = 1-6/species; replicates/test = 2-3. Copper values adjusted to 50 mg/L hardness
        (US EPA 1985) except for Cyprinodontidae.
Family
Species common name

Acipenseridae
Shovelnose sturgeon
Atlantic sturgeon**
Shortnose sturgeon**
Cyprinidae
Fathead minnow*
Bonytail chub**
Cape Fear shiner**
Colorado pikeminnow**
Spotfin chub**
Catostomidae
Razorback sucker**
Salmonidae
Rainbow trout*
Apache trout**
Greenback cutthroat trout**
Lahontan cutthroat trout**
Cyprinodontidae4
Sheepshead minnow*, 2ppt
Sheepshead minnow*, 15ppt
Leon Springs pupfish**, 2ppt
Leon Springs pupfish **, 15ppt
Poecillidae
Gila topminnow**
Percidae
Fountain darter**
Greenthroat darter**
Bufonidae
Boreal toad**
Ranidae
Southern leopard frog
Cop|
96-h LC50 fua/L


51 c'd'e
198
25 e, f. g

144"
6gb,c,d
35d.e.f.g
132 b
35d,.e,f,g

84 b< c' d

ige.f.g
>9.5
21 f,9
630 a
>204
1306a
>204
4g c. d, e, f

18 9
95 b c-

23 e-'-g


44 c. d, e, f. g
aer
J1 95% CL2


37
16
20

133
65
31
117
31

76

17
21
20
518
1018
42

15
66

21


39


-66
-21
-31

-158
-74
-40
-150
-393

-92

-20
-28
-23
-791
-2384
-56

-21
-226

-25


-49
4-Nonylphenol
96-h LC50 (ua/U1 95% CL2




81 'J

272 b' Ci • e
264 b> Ci di e' *
215c.d,e,f
231 c'd'e-f
98g,h,i,.j

182c,d,e,f,g

1 91 °! ^ e' *• ^
161 d,e,f,g,h
153 e'f'9'hj
•\ 63 c, d, e, f, g
472 a, b
30Qa,b.c,d
553 a
132f.g,h,i
243b.c,d,e,f

89 ^u
1 79 c, d, e, f, g

137f,g,h,i


332a,b,c






260 - 283
241 - 290
176-259
219-2443
93-1033

170- 193

183-200
148- 175
141 -169
149-178
422 - 5283
259 - 344
417- 1230
91 - 167


74-109
133-291

131 - 1443


289 - 392
* Surrogate test species.
**Listed species.
1 Means with same letter are not significantly different (p > 0.05).
2 Confidence limits.
3 Confidence limits estimated by Spearman-Karber techniques (Hamilton et al. 1977 a,b).
4 Cyprinodontids were tested under two salinity conditions — 2 or 15 parts per thousand salinity (ppt).
                                             19

-------
Table 4.  Acute static toxicity of pentachlorophenol and permethrin to surrogate test species
         and endangered species. 1Number of tests = 1 -6/species; replicates/test = 2-3.
         Pentachlorophenol values adjusted to pH 6.5 (U.S EPA 1986) except for Cyprinodontidae.
Family
Species common name
Acipenseridae
Shortnose sturgeon**
Cyprinidae
Fathead minnow*
Bonytail chub**
Cape Fear shiner**
Colorado pikeminnow**
Spotfin chub**
Catostomidae
Razorback sucker**
Salmonidae
Rainbow trout*
Apache trout**
Greenback cutthroat trout**
Lahontan cutthroat trout**
Cyprinodontidae5
Sheepshead minnow*, 2ppt
Sheepshead minnow*. 15ppt
Leon Springs pupfish**,2ppt
Leon Springs pupfish**,15ppt
Poecillidae
Gila topminnow**
Percidae
Fountain darter**
Greenthroat darter**
Bufonidae
Boreal toad**
Ranidae
Southern leopard frog
Pentachlorophenol
96-h LC50 (ua/L)1 95%

11"

40c.d.e
37c.d.e.f
35def
OH s f .g. h
39 c. d e

4Qc.d.e

25 d- e. f. g
17fg.h
33d.e.f..g
28 d e '- s

40 c .d.e
191 a
op b. c
107 ab

56D.C.d

15g.h
26de'9

98 ab

4gt.c.d

9.3-

38-
35-
32-
20-
37-

39-

24-
15-
17-
26-


163-
73-
82-

49-

12-
24-

86-

44-
CL2-

• 14

43
393
383
23
413

413

26
18
181
30


224
92
125

65

18
293

113

56
Permethrin
96-h LC50 (ua/LV1 95%CL2

NC4

9.5 cd
39 a
3.5 e-f
26 b.=
1.7'

6.1 d e

3.3 8f
2.0'
2.8 e-i
1.7'

17abc
23 a b
19 a°c
21 a.b

10b.c.d

3.3ef
2.8 ef

> 10

20 a be



8.9
27
3.2
20
1.5

5.5

3.1
1.8
1.4
1.5

15

16




2.8
2.5



16



-10
-80
-3.73
-42
- 1.9

-6.8

-3.5
-2.2
-4.2
- 1.8

- 193

-22




-4.0
-3.2



-26
* Surrogate test species.
"Listed species.
1 Means with same letter are not significantly different (p > 0.05).
2 Confidence limits.
3 Confidence limits estimated by Spearman-Karber techniques (Hamilton et al. 1977 a,b).
4 Could not be calculated.
5 Cyprinodontids were tested under two salinity conditions, 2 or 15 parts per thousand salinity (ppt).
                                            20

-------
Tables. Acute toxicity sensitivity rankings by 96-h LC50. Rank = sum of
         rankings among chemicals within a species/n for chemicals
         having a 96-h LC50.


      Species common name                       96-h LC50 rank1
      Atlantic sturgeon*                                2.02
      Fountain darter*                                   2.4
      Shortnose sturgeon*                               3.0
      Apache trout*                                     3.6
      Greenback cutthroat trout*                    .      4.8
      Rainbow trout                                     5.2
      Lahontan cutthroat trout*                           5.4
      Spotfin chub*                                     6.6
      Greenthroat darter*                                7.4
      Shovelnose sturgeon                             9.02
      Cape Fear shiner*                                 9.0
      Leon Springs pupfish*,15ppt                        9.8
      Razorback sucker*                               10.6
      Colorado pikeminnow*                            10.8
      Gila topminnow*                                  11.0
      Boreal toad*                                     11.2
      Bonytail chub*                                    12.2
      Fathead minnow                                  13.2
      Southern leopard frog                             13.6
      Sheepshead minnow, 2ppt                         14.0
      Sheepshead minnow, 15ppt                        14.2
      Leon Springs pupfish*, 2ppt                       15.4
      Desert pupfish*                                  18.03
      Other amphibians                               >18.03
     *Listed species.
     10nly three values were significantly (p < 0.05) less than that for rainbow
      trout (4-nonylphenol, shovelnose sturgeon and fountain darter, pentachloro-
      phenol, shortnose sturgeon).
     2 One test with copper.
     3 One test with carbaryl.
                                    21

-------
Table 6.  Chronic toxicity (ug/L) of copper (50 mg/L hardness) and
          pentachlorophenol (6.5 pH) to fathead minnow, spotfin
          chub, rainbow trout, and fountain darter.1 Numbers in
          parentheses are 95% confidence limits.
Species common
name

Fathead minnow
Spotfin chub
Rainbow trout
Fountain darter

Fathead minnow
Spotfin chub
Rainbow trout
Fountain darter
Tests Chronic Value
(n) Survival
Copper
3 9.5
(7.0-13)
1 11
•(8.1-15)
2 5.6
(4.2-7.7)
2 2.7
(2.1-3.5)
Pentachlorophenol
4 27a
(20-38)
1 33a
(24-45)
2 17°
(12-24)
1 8.7b
(6.4-12)
(NOEC-LOEC)2
Growth3

2.8
(2.0-3.9)
5.6
(3.9-8.1)
4.2
(3.0-5.6)
2.7
(2.1-3.5)

27a
(20-38)
8.0°
(5.7-11)
8.3°
(5.9-12)
3.9°
(2.5-6.4)
  1 Means with same letter are not significantly different (p <0.05).
  2 Geometric mean of chronic values (NOEC, No-observed-effect
    concentration; LOEC, lowest observed effect concentration).
   3 Dry weight.
                             22

-------
Table 7, Interspecies correlations (X2 = a + bXJ for all species and five chemicals
        with fathead minnow as the surrogate species.  X1 = log 96-h LC50 for
        fathead minnow and X2 = log 96-h  LC50 for other species in |jg/L
Family
Species common name
Acipenseridae
Shortnose sturgeon
Cyprinidae
Bonytail chub
Cape Fear shiner
Colorado pikeminnow
Spotfin chub
Catostomidae
Razorback sucker
Salmondiae
Apache trout
Greenback cutthroat trout
Lahontan cutthroat trout
Rainbow trout
Cyprinodontidae
Leon Springs pupfish
Sheepshead minnow
Poecillidae
Gila topminnow
Percidae
Fountain darter
Greenthroat darter
Bufonidae
Boreal toad
Ranidae
Southern leopard frog
n
4
5
5
5
5

5

5
4
5
5
4
4

4

5
5

4

5
Intercept (a)
-0.791
0.560
-0.471
0.351
-0.684

-0.175

-0.596
-0.259
-0.676
-0.414
0.724
0.888

0.284

-0.508
-0.349

-0.496

0.091
Slope (b)
1 .092**
0.745**
1.098**
0.823**
1.129**

1.017**

1 .033**
0.959*
1 .096**
0.993**
0.674*
0.684*

0.793

0.979**
1 .026**

1.166

0.973**
r
0.993
0.947
0.980
0.967
0.973

0.996

0.980
0.983
0.968
0.962
0.970
0.968

0.907

0.982
0.989

0.882

0.952
 *Slope significant from zero, p < 0.05.
**Slope significant from zero, p < 0.01.
                                    23

-------
Table 8. Interspecies correlations (X2 = a + bX,) for all species and five chemicals
        with rainbow trout as the surrogate species.  X, = log 96-h LC50 for
        rainbow trout and X2 = log 96-h LC50 for other species in ug/L.
Family
Species common name
Acipenseridae
Shortnose sturgeon
Cyprinidae
Bonytail chub
Cape Fear shiner
Colorado pikeminnow
Fathead minnow
Spotfin chub
Catostomidae
Razorback sucker
Salmondiae
Apache trout
Greenback cutthroat trout
Lahontan cutthroat trout
Cyprinodontidae
Leon Springs pupfish
Sheepshead minnow
Poecillidae
Gila topminnow
Percidae
Fountain darter
Greenthroat darter
Bufonidae
Boreal toad
Ranidae
Southern leopard frog
n
4
5
5
5
5
5

5

5
4
5
4
4

4

5
5

4

5
Intercept (a)
-0.184
0.925
0.033
0.833
0.550
-0.133

0.360

-0.118
0.019
-0.195
0.952
1.092

0.644

-0.049
0.211

-0.054

0.520
Slope (b)
1.022*
0.719*
1.080**
0.750*
0.932**
1.093**

0.962**

1.014**
0.973**
1.090**
0.665*
0.690*

0.778**

0.958**
0.959**

1.192

0.968**
r
0.967
0.944
0.995
0.910
0.962
0.972

0.973

0.993
0.996
0.994
0.956
0.976

0.997

0.991
0.954

0.938

0.976
 *Slope significant from zero, p < 0.05.
 "Slope significant from zero, p < 0.01.
                                       24

-------
Table  9.  Interspecies correlations (X2 = a + bXJ for all species and five chemjcals
          with sheepshead minnow as the surrogate species. X, = log 96-h LC50
          for sheepshead minnow (15ppt salinity) and X2 = log 96-h LC50 for other
          species in |jg/L.
Family
Species common name
Acipenseridae
Shortnose sturgeon
Cyprinidae
Bonytail chub
Cape Fear shiner
Colorado pikeminnow
Fathead minnow
Spotfin chub
Catostomidae
Razorback sucker
Salmondiae
Apache trout
Greenback cutthroat trout
Lahontan cutthroat trout
Rainbow trout
Cyprinodontidae
Leon Springs pupfish
Poecillidae
Gila topminnow
Percidae
Fountain darter
Greenthroat darter
Bufonidae
Boreal toad
Ranidae
Southern leopard frog
n

3

4
4
4
4
4

4

4
4
4
4

4

3

4
4

3

4
. Intercept (a)

-2.911

-0.017
-1.646
-0.360
-1.081
-2.050

-1.304

-1.705
-1.417
-1.906
-1.419

-0.110

-0.539

-1.489
-1.569

-2.563

-0.760
slope(b)

1.838

0.959
1 .537**
1.054
1.371*
1.631**

1.417*

1.439*
1 .366**
1 .559**
1 .380*

0.968**

1.105

1 .345*
1 .442*

1 .950

1.308*
r

0.975

0.887
0.986
0.875
0.968
0.999

0.982

0.973
0.989
0.989
0.976

0.985

0.952

0.973
0.983

0.995

0.948
 *Slope significant from zero, p < 0.05.
**Slope significant from zero, p < 0.01.
                                          25

-------
 Species common mime.                   Species number         1
                                                                                                                                                                                           10            11
                                                                                                                                                                                                                                   13           14           15           Id            17            IS
 Colorado piU: mimi
                                                                    0.97 V1       0.97-1  ''      O.l'-'l
                                                                                                                                                                0,99s1'        l.OOO1'
SlKxpsln.-;nl iniiiiiuu 1 Sppl
l7
                                                                                                                                                                                          •i            •!

-------
    Table 11. Observed and estimated 96-h LCSOs (ug/L) for five chemicals and 15 aquatic vertebrates using
             interspecies correlation analysis (ICE, Asfaw et al. 2003) and surrogate species (fathead minnow,
             rainbow trout, or sheepshead minnow) acute toxicity values. The surrogate species model having
             the highest r value was used for estimations.
Estimated species
Shortnose sturgeon
Bonytail chub
Cape Fear shiner
Colorado pikeminnow
Spotfin chub
Razorback sucker
Apache trout
Greenback cutthroat
trout
Lahontan cutthroat
trout
Leon Springs pupfish
Gila topminnow
Fountain darter
Greenthroat darter
Boreal toad
Southern leopard frog
Surrogate
Species
FHM1
FHM
RBT2
FHM
SHM3
FHM
RBT
RBT
RBT
SHM
RBT
RBT
FHM
SHM
RBT
Carbaryl
19494
(1837)5
3044
(2121)
4264
(3678)
3038
(2554)
3416
(3127)
4325
(3997)
1435
(1580)
1553
(1591)
2221
(2346)
2017
(1517)
>3000
1615
(1215)
2143
(2892)
12303
(11660)
7964
(4856)
Copper
25
(37)
69
(147)
35
(26)
132
(134)
35
(64)6
84
(105)
25
(15)
>9.5
21
(16)
>204
48
(44)
18
(15)
95
(73)
23
(197)
44
(57)
4-Nonylphenol
81
(74)
264
(236)
215
(314)
231
(226)
98
(98)
182
(200)
161
(157)
153
(173)
163
(196)
132
(194)
243
(262)
89
(137)
179
(141)
137
(185)
332
(535)
Pentachloro-
phenol
11
(9.1)
37
(57)
35
(35)
21
(47)
39
(47)
40
(28)
17
(20)
33
(24)
28
(21)
107
(125)
56
(54)
15
(20)
26
(20)
98
(77)
49
(75)
Permethrin
ND8
39
(19)
3.5
(3.9)
26
(14)
1.7
(1.5)
6.1
(6.6)
2.0
(2.6)
2.8
(3.3)
1.7
(2.3)
21
(16)
10
(11)
3.3
(2.8)
2.8
(4.5)
>10
20
(11)
1 FHM = fathead minnow.
2 RBT = rainbow trout.
3 SHM -sheepshead minnow.
4 Observed 96-h LC50.
5 Estimated 96-h LC50 using ICE (Asfaw et al. 2003).
6 Copper value not available for sheepshead minnow, fathead minnow model and copper value were used.
7 Copper value not available for sheepshead minnow, rainbow trout model and copper value were used.

                                            27

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Table 12.  Observed and estimated (ACE, Ellersieck et al. 2003)
          chronic toxicities (ug/L) of copper (50 mg/L hardness) and
          pentachlorophenol (6.5 pH) for fathead minnow, spotfin
          chub, rainbow trout, and fountain darter.  Predicted no-effect
          chronic values were determined using raw acute toxicity
          data and the software ACE (Ellersieck et al. 2003).1
Chronic Value (NOEC-LOEC)2 ACE (95% CU
Species

Fathead minnow
Fathead minnow4
Spotfin chub
Rainbow trout
Rainbow trout5
Fountain darter

Fathead minnow
Spotfin chub
Rainbow trout
Fountain darter
Survival

9.5
(7.0-13)
6.9
(5.4-8.9)
11
(8.1 - 15)
5.6
(4.2 - 7.7)

2.7
(2.1 -3.5)

27a
(20 - 38)
33a
(24 - 45)
17b
(12-24)
8.7b
(6.4- 12)
Growth3
Copper
2.8
(2.0 - 3.9)
6.9
(5.4 - 8.9)
5.6
(3.9-8.1)
4.2
(3.0 - 5.6)

2.7
(2.1 -3.5)
Pentachlorophenol
27a
(20 - 38)
8.0b
(5.7-11)
8.3b
(5.9- 12)
3.9b
(2.5 - 6.4)


3.5
(0.9 - 8.2)
11
(2.8- 19)
6.2
(2.5-9.9)
2.3
(-50 - 55)
1.4
(0.5 - 4.5)
1.6
(0.4 - 2.8)

10
(4.1 -16)
11
(4.9- 18)
13
(3.4 - 22)
4.1
(1.2-6.9)
1  Means with same letter are not significantly different (p < 0.05). ACE
  estimates were not analyzed since each is a single value.
2  Geometric mean of chronic values (NOEC, no-observed effect
  concentration ; LOEC, lowest observed effect concentration).
3  Dry weight.
4  Data from Spehar and Fiandt (1986).
5  Data from Stubblefield (1990).
                              28

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Table 13.  Calculated 5lh percentile values for observed and estimated acute toxicity data (96-h LCSOs
          in ug/L) using three methods (Solomon et al. 1996, 2000; Aldenberg and Jaworska 2000;
          Stephanetal. 1985).
Chemical
Observed
Data
ICE-FHM,
RBT, SHM1
ICE-
FHM2
Solomon etal. (1996,
Carbaryl
Copper
4-Nonylphenol
Pentachlorophenol
Permethrin

Carbaryl
Copper
4-Nonylphenol
Pentachlorophenol
Permethrin
1073
13
90
11
1.1

1809
24
133
22
2.7
993
12
83
12
1.1
Aldenberg
1655
24
134
24
2.4
1252
35
73
8.0
1.5
ECOSAR-
FHM35
2000)
3721
-
39
128
1.4
ASTER-
FHM45

-
-
24
45
-
and Jaworska (2000)
1830
NC7
114
14
3.1
6019
-
NC
189
2.9
-
-
NC
NC
-
Stephanetal. (1985)
Carbaryl
Copper
4-Nonylphenol
Pentachlorophenol
Permethrin
1409
18
81
12
1.6
1250
15
77
11
1.3
1372
37
75
9.4
2.0
4207
-
41
128
1.9
-
-
26
47
-
                                           29

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Table 14.  Calculated 5:ilpercentile values (ug/L) for observed and estimated chronic toxicity data using
          three methods (Solomon et al. 1996, 2000; Aldenberg and Jaworska 2000; Stephan et al.
          1985).
Chemical

Copper
Pentachlorophenol
Observed Observed Data Observed Data Observed Data
Data1 +ACE FD, SFC2 +ICE/ACR FD, FHM, Dm +ICE/
SFC3 AC Pi4
Solomon et al.
2.3 1.9
2.5 2.8
(1996.2000)
2.3
2.8

1.2
3,2
Aldenberg and Jaworska (2000)
Copper
Pentachlorophenol

Copper
Pentachlorophenol
6.8 6.5
6.9 7.7
Stephan et
2.3 1.4
0.16 0.75
6.8
6.5
al. (1985)
2.4
0.59
3.2
7.9

0.45
1.2
1  Chronic data from criteria document (U.S. EPA 1985, 1986) plus chronic data for fountain darter (FD)
 and spotfin chub (SFC).
2 Chronic data from criteria document plus chronic data for fountain darter and spotfin chub estimated
-by ACE (Ellersieck et al. 2003).
3 Chronic data from criteria document plus chronic data for fountain darter and spotfin chub estimated
 by ICE for acute values followed with division by ACR for estimated chronic values.
4 Chronic data for Daphina magna and fathead minnow from criteria document with acute values for all
 other species estimated by ICE followed with division by ACR for estimated chronic values.
                                             30

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                                             33

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